VuoCompiler.cc

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#include <string.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sstream>
#include <CoreFoundation/CoreFoundation.h>
#include "VuoCompiler.hh"
#include "VuoCompilerBitcodeGenerator.hh"
#include "VuoCompilerCodeGenUtilities.hh"
#include "VuoCompilerComposition.hh"
#include "VuoCompilerDiagnosticConsumer.hh"
#include "VuoCompilerException.hh"
#include "VuoCompilerGenericType.hh"
#include "VuoCompilerGraph.hh"
#include "VuoCompilerGraphvizParser.hh"
#include "VuoCompilerIssue.hh"
#include "VuoCompilerNode.hh"
#include "VuoCompilerPort.hh"
#include "VuoCompilerPortClass.hh"
#include "VuoCompilerPublishedInputNodeClass.hh"
#include "VuoCompilerPublishedOutputNodeClass.hh"
#include "VuoCompilerGroup.hh"
#include "VuoCompilerTriggerDescription.hh"
#include "VuoComposition.hh"
#include "VuoException.hh"
#include "VuoGenericType.hh"
#include "VuoModuleCompiler.hh"
#include "VuoModuleCompilationQueue.hh"
#include "VuoNode.hh"
#include "VuoNodeClass.hh"
#include "VuoNodeSet.hh"
#include "VuoPublishedPort.hh"
#include "VuoRunner.hh"
#include "VuoRunningCompositionLibraries.hh"
#include "VuoStringUtilities.hh"
 
#if VUO_PRO
#include "VuoPro.hh"
#endif
 
map<string, VuoFileUtilities::File *> VuoCompiler::Environment::moduleCacheFileForLocking;
dispatch_queue_t VuoCompiler::Environment::moduleCacheBuildingQueue = dispatch_queue_create("org.vuo.compiler.cache", NULL);
const string VuoCompiler::Environment::pidCacheDirPrefix = "pid-";
set<VuoCompiler *> VuoCompiler::allCompilers;
dispatch_queue_t VuoCompiler::environmentQueue = dispatch_queue_create("org.vuo.compiler.environment", NULL);
map<string, vector< vector<VuoCompiler::Environment *> > > VuoCompiler::sharedEnvironments;
map<string, map<string, vector<VuoCompiler::Environment *> > > VuoCompiler::environmentsForCompositionFamily;
dispatch_group_t VuoCompiler::moduleSourceCompilersExistGlobally = dispatch_group_create();
string VuoCompiler::vuoFrameworkInProgressPath;
 
dispatch_queue_t llvmQueue = NULL;  
 
llvm::LLVMContext *VuoCompiler::globalLLVMContext = nullptr;  
 
static void __attribute__((constructor)) VuoCompiler_init(void)
{
    // Increase the open-files limit (macOS defaults to 256).
    struct rlimit rl{OPEN_MAX, OPEN_MAX};
    getrlimit(RLIMIT_NOFILE, &rl);
    rl.rlim_cur = MIN(OPEN_MAX, rl.rlim_max);
    if (setrlimit(RLIMIT_NOFILE, &rl))
        VUserLog("Warning: Couldn't set open-files limit: %s", strerror(errno));
 
 
    llvmQueue = dispatch_queue_create("org.vuo.compiler.llvm", NULL);
 
    dispatch_sync(llvmQueue, ^{
                      // llvm::InitializeNativeTarget();
                      llvm::InitializeAllTargetMCs();
                      llvm::InitializeAllTargets();
                      // TargetRegistry::printRegisteredTargetsForVersion();
 
                      VuoCompiler::globalLLVMContext = new llvm::LLVMContext;
 
                      // Set up a diagnostic handler so that llvm::LLVMContext::diagnose doesn't exit
                      // when a call to llvm::Linker::linkInModule generates an error.
                      VuoCompiler::globalLLVMContext->setDiagnosticHandler([](const DiagnosticInfo &DI, void *context) {
                          string message;
                          raw_string_ostream stream(message);
                          DiagnosticPrinterRawOStream printer(stream);
                          DI.print(printer);
                          stream.flush();
                          if (! message.empty())
                          {
                              const char *severityName;
                              if (DI.getSeverity() == DS_Error)
                                  severityName = "error";
                              else if (DI.getSeverity() == DS_Warning)
                                  severityName = "warning";
                              else
                                  severityName = "note";
 
                              VuoLog(VuoLog_moduleName, __FILE__, __LINE__, "llvmDiagnosticHandler", "%s: %s", severityName, message.c_str());
                          }
                      });
 
                      // If the Vuo compiler/linker...
                      //   1. Loads a node class that uses dispatch_object_t.
                      //   2. Generates code that uses dispatch_object_t.
                      //   3. Links the node class into a composition.
                      //   4. Generates more code that uses dispatch_object_t.
                      // ... then Step 4 ends up with the wrong llvm::Type for dispatch_object_t.
                      //
                      // A workaround is to generate some code that uses dispatch_object_t before doing Step 1.
                      //
                      // https://b33p.net/kosada/node/3845
                      // http://lists.cs.uiuc.edu/pipermail/llvmdev/2012-December/057075.html
                      Module module("", *VuoCompiler::globalLLVMContext);
                      VuoCompilerCodeGenUtilities::getDispatchObjectType(&module);
 
                      // Workaround for a possibly related error where the compiler ends up with the wrong
                      // llvm::Type for dispatch_semaphore_s.  https://b33p.net/kosada/node/10545
                      VuoCompilerCodeGenUtilities::getDispatchSemaphoreType(&module);
 
                      // Load the NodeContext and PortContext struct types preemptively to make sure that
                      // their fields get the right dispatch types. If these struct types were to be loaded
                      // first from a subcomposition module, they'd get the wrong dispatch types.
                      // https://b33p.net/kosada/node/11160
                      VuoCompilerCodeGenUtilities::getNodeContextType(&module);
                      VuoCompilerCodeGenUtilities::getPortContextType(&module);
                  });
}
 
VuoCompiler::ModuleInfo::ModuleInfo(Environment *environment, const string &searchPath, const string &relativePath,
                                    bool isSourceFile, bool isSubcomposition)
{
    VuoFileUtilities::File *file = new VuoFileUtilities::File(searchPath, relativePath);
    initialize(environment, searchPath, file, isSourceFile, isSubcomposition);
}
 
VuoCompiler::ModuleInfo::ModuleInfo(Environment *environment, const string &searchPath, VuoFileUtilities::File *file,
                                    bool isSourceFile, bool isSubcomposition)
{
    initialize(environment, searchPath, file, isSourceFile, isSubcomposition);
}
 
void VuoCompiler::ModuleInfo::initialize(Environment *environment, const string &searchPath, VuoFileUtilities::File *file,
                                         bool isSourceFile, bool isSubcomposition)
{
    this->environment = environment;
    this->searchPath = searchPath;
    this->file = file;
    moduleKey = getModuleKeyForPath(file->getRelativePath());
    sourceCodeOverridden = false;
    lastModified = VuoFileUtilities::getFileLastModifiedInSeconds(file->isInArchive() ? file->getArchivePath() : file->path());
    longestDownstreamPath = 0;
    attempted = false;
    loading = nullptr;
 
#if VUO_PRO
    init_Pro();
#endif
 
    if (isSourceFile)
    {
        loading = dispatch_group_create();
        sourceCode = file->getContentsAsString();
 
        if (isSubcomposition)
        {
            try
            {
                containedNodeClasses = VuoCompilerGraphvizParser::getNodeClassNamesFromCompositionFile(file->path());
            }
            catch (...)
            {
                // Issues parsing the composition will be caught later when compiling it.
            }
        }
    }
}
 
VuoCompiler::ModuleInfo::~ModuleInfo(void)
{
#if VUO_PRO
    fini_Pro();
#endif
 
    delete file;
 
    if (loading)
        dispatch_release(loading);
}
 
VuoCompiler::Environment * VuoCompiler::ModuleInfo::getEnvironment(void) const
{
    return environment;
}
 
string VuoCompiler::ModuleInfo::getSearchPath(void) const
{
    return searchPath;
}
 
string VuoCompiler::ModuleInfo::getModuleKey(void) const
{
    return moduleKey;
}
 
VuoFileUtilities::File * VuoCompiler::ModuleInfo::getFile(void) const
{
    return file;
}
 
string VuoCompiler::ModuleInfo::getSourceCode(void) const
{
    return sourceCode;
}
 
void VuoCompiler::ModuleInfo::setSourceCode(const string &sourceCode)
{
    this->sourceCode = sourceCode;
}
 
void VuoCompiler::ModuleInfo::revertSourceCode(void)
{
    sourceCode = file->getContentsAsString();
}
 
bool VuoCompiler::ModuleInfo::isSourceCodeOverridden(void) const
{
    return sourceCodeOverridden;
}
 
void VuoCompiler::ModuleInfo::setSourceCodeOverridden(bool overridden)
{
    sourceCodeOverridden = overridden;
}
 
bool VuoCompiler::ModuleInfo::isNewerThan(ModuleInfo *other) const
{
    return lastModified > other->lastModified;
}
 
bool VuoCompiler::ModuleInfo::isNewerThan(unsigned long ageInSeconds) const
{
    return lastModified > ageInSeconds;
}
 
bool VuoCompiler::ModuleInfo::isOlderThan(unsigned long ageInSeconds) const
{
    return lastModified < ageInSeconds;
}
 
void VuoCompiler::ModuleInfo::setLastModifiedToNow(void)
{
    struct timeval t;
    gettimeofday(&t, NULL);
    lastModified = t.tv_sec;
}
 
set<string> VuoCompiler::ModuleInfo::getContainedNodeClasses(void) const
{
    return containedNodeClasses;
}
 
int VuoCompiler::ModuleInfo::getLongestDownstreamPath(void) const
{
    return longestDownstreamPath;
}
 
void VuoCompiler::ModuleInfo::setLongestDownstreamPath(int pathLength)
{
    longestDownstreamPath = pathLength;
}
 
bool VuoCompiler::ModuleInfo::getAttempted(void) const
{
    return attempted;
}
 
void VuoCompiler::ModuleInfo::setAttempted(bool attempted)
{
    this->attempted = attempted;
}
 
dispatch_group_t VuoCompiler::ModuleInfo::getLoadingGroup(void) const
{
    return loading;
}
 
void VuoCompiler::ModuleInfo::dump() const
{
    fprintf(stderr, "module %s:\n"
                    "\tloadingGroup=%p\n"
                    "\tsearchPath=%s\n"
                    "\tattempted=%d\n"
                    "\tenvironment=%s\n"
                    "\tfile=%s%s%s\n"
                    "\tsourceCodeOverridden=%d\n"
                    "\tsourceCode=%s\n"
                    "\tcontainedNodeClasses:\n",
            moduleKey.c_str(),
            loading,
            searchPath.c_str(),
            attempted,
            environment->getCompiledModuleCachePath().c_str(),
            file->isInArchive() ? file->getArchivePath().c_str() : "",
            file->isInArchive() ? "::" : "",
            file->isInArchive() ? file->getRelativePath().c_str() : file->path().c_str(),
            sourceCodeOverridden,
            sourceCode.c_str());
    for (auto i: containedNodeClasses)
        fprintf(stderr, "\t\t%s\n", i.c_str());
}
 
VuoCompiler::DependencyGraphVertex * VuoCompiler::DependencyGraphVertex::vertexForDependency(const string &dependency, VuoDirectedAcyclicGraph *graph)
{
    VuoDirectedAcyclicGraph::Vertex *v = graph->findVertex(dependency);
    if (v)
        return dynamic_cast<DependencyGraphVertex *>(v);
 
    DependencyGraphVertex *vv = new DependencyGraphVertex();
    vv->dependency = dependency;
    vv->environment = NULL;
    vv->compatible = true;
    return vv;
}
 
string VuoCompiler::DependencyGraphVertex::getDependency(void)
{
    return dependency;
}
 
VuoCompiler::Environment * VuoCompiler::DependencyGraphVertex::getEnvironment(void)
{
    return environment;
}
 
void VuoCompiler::DependencyGraphVertex::setEnvironment(Environment *environment)
{
    this->environment = environment;
}
 
string VuoCompiler::DependencyGraphVertex::key(void)
{
    return dependency;
}
 
VuoCompiler::ModuleInfoIterator::ModuleInfoIterator(map<string, map<string, ModuleInfo *> > *allModuleInfos,
                                                    const string &overriddenCompiledModuleCachePath)
{
    this->allModuleInfos = allModuleInfos;
    this->overriddenCompiledModuleCachePath = overriddenCompiledModuleCachePath;
    hasSearchModuleKeys = false;
    initialize();
}
 
VuoCompiler::ModuleInfoIterator::ModuleInfoIterator(map<string, map<string, ModuleInfo *> > *allModuleInfos,
                                                    const string &overriddenCompiledModuleCachePath,
                                                    const set<string> &searchModuleKeys)
{
    this->allModuleInfos = allModuleInfos;
    this->overriddenCompiledModuleCachePath = overriddenCompiledModuleCachePath;
    this->searchModuleKeys = searchModuleKeys;
    hasSearchModuleKeys = true;
    initialize();
}
 
void VuoCompiler::ModuleInfoIterator::initialize(void)
{
    currSearchPath = allModuleInfos->begin();
    hasCurrModuleKey = false;
 
    if (! overriddenCompiledModuleCachePath.empty())
    {
        auto i = allModuleInfos->find(overriddenCompiledModuleCachePath);
        if (i != allModuleInfos->end())
        {
            std::transform(i->second.begin(), i->second.end(),
                           std::inserter(overriddenModuleKeys, overriddenModuleKeys.begin()),
                           [](const pair<string, ModuleInfo *> &p) { return p.first; });
        }
    }
}
 
VuoCompiler::ModuleInfo * VuoCompiler::ModuleInfoIterator::next(void)
{
    for ( ; currSearchPath != allModuleInfos->end(); ++currSearchPath)
    {
        if (! hasCurrModuleKey)
        {
            currModuleKey = currSearchPath->second.begin();
            hasCurrModuleKey = true;
        }
 
        bool isOverriddenCompiledModuleCachePath = ! overriddenCompiledModuleCachePath.empty() &&
                                                   VuoFileUtilities::arePathsEqual(currSearchPath->first, overriddenCompiledModuleCachePath);
 
        for ( ; currModuleKey != currSearchPath->second.end(); ++currModuleKey)
        {
            if ((! hasSearchModuleKeys || searchModuleKeys.find(currModuleKey->first) != searchModuleKeys.end()) &&
                    (isOverriddenCompiledModuleCachePath || overriddenModuleKeys.find(currModuleKey->first) == overriddenModuleKeys.end()))
            {
                ModuleInfo *moduleInfo = currModuleKey->second;
                ++currModuleKey;
                return moduleInfo;
            }
        }
 
        hasCurrModuleKey = false;
    }
 
    return NULL;
}
 
VuoCompiler::Environment::Environment(string target, bool builtIn, bool generated)
    : target(target), builtIn(builtIn), generated(generated)
{
    compilersToNotifyQueue = dispatch_queue_create("org.vuo.compiler.notify", 0);
    moduleSearchPathContentsChangedQueue = dispatch_queue_create("org.vuo.compiler.watch", 0);
    lastModuleCacheRebuild = 0;
    isModuleCacheableDataDirty = false;
    isModuleCacheInitialized = false;
    isModuleCacheAvailable = false;
    dependencyGraph = new VuoDirectedAcyclicGraph();
    compositionDependencyGraph = new VuoDirectedAcyclicGraph();
    moduleCompilationQueue = new VuoModuleCompilationQueue();
}
 
VuoCompiler::Environment::~Environment(void)
{
    stopWatchingModuleSearchPaths();
    dispatch_sync(moduleSearchPathContentsChangedQueue, ^{});
 
    dispatch_release(moduleSearchPathContentsChangedQueue);
    dispatch_release(compilersToNotifyQueue);
 
    for (map<string, VuoCompilerNodeClass *>::iterator i = nodeClasses.begin(); i != nodeClasses.end(); ++i)
        destroyModule(i->second);
 
    for (map<string, VuoCompilerType *>::iterator i = types.begin(); i != types.end(); ++i)
        destroyModule(i->second);
 
    for (map<string, VuoCompilerModule *>::iterator i = libraryModules.begin(); i != libraryModules.end(); ++i)
        destroyModule(i->second);
 
    for (set<VuoCompilerGenericType *>::iterator i = genericTypes.begin(); i != genericTypes.end(); ++i)
    {
        VuoType *base = (*i)->getBase();
        delete *i;
        delete base;
    }
 
    for (map<string, VuoNodeSet *>::iterator i = nodeSetForName.begin(); i != nodeSetForName.end(); ++i)
        delete i->second;
 
    for (map<string, map<string, ModuleInfo *> >::iterator i = moduleFilesAtSearchPath.begin(); i != moduleFilesAtSearchPath.end(); ++i)
        for (map<string, ModuleInfo *>::iterator j = i->second.begin(); j != i->second.end(); ++j)
            delete j->second;
 
    for (map<string, map<string, ModuleInfo *> >::iterator i = sourceFilesAtSearchPath.begin(); i != sourceFilesAtSearchPath.end(); ++i)
        for (map<string, ModuleInfo *>::iterator j = i->second.begin(); j != i->second.end(); ++j)
            delete j->second;
 
    delete dependencyGraph;
    delete compositionDependencyGraph;
}
 
string VuoCompiler::Environment::getTarget()
{
    return target;
}
 
void VuoCompiler::Environment::addCompilerToNotify(VuoCompiler *compiler)
{
    dispatch_sync(compilersToNotifyQueue, ^{
                      compilersToNotify.insert(compiler);
                  });
}
 
void VuoCompiler::Environment::removeCompilerToNotify(VuoCompiler *compiler)
{
    dispatch_sync(compilersToNotifyQueue, ^{
                      compilersToNotify.erase(compiler);
                  });
}
 
map<string, VuoCompilerNodeClass *> VuoCompiler::Environment::getNodeClasses(void)
{
    return nodeClasses;
}
 
VuoCompilerNodeClass * VuoCompiler::Environment::getNodeClass(const string &moduleKey)
{
    map<string, VuoCompilerNodeClass *>::iterator nodeClassIter = nodeClasses.find(moduleKey);
    if (nodeClassIter != nodeClasses.end())
        return nodeClassIter->second;
 
    return NULL;
}
 
VuoCompilerNodeClass * VuoCompiler::Environment::takeNodeClass(const string &moduleKey)
{
    VuoCompilerNodeClass *nodeClass = NULL;
 
    map<string, VuoCompilerNodeClass *>::iterator nodeClassIter = nodeClasses.find(moduleKey);
    if (nodeClassIter != nodeClasses.end())
    {
        nodeClass = nodeClassIter->second;
 
        nodeClasses.erase(nodeClassIter);
        removeFromDependencyGraph(nodeClass);
        modulesChanged();
    }
 
    return nodeClass;
}
 
map<string, VuoCompilerType *> VuoCompiler::Environment::getTypes(void)
{
    return types;
}
 
VuoCompilerType * VuoCompiler::Environment::getType(const string &moduleKey)
{
    map<string, VuoCompilerType *>::iterator typeIter = types.find(moduleKey);
    if (typeIter != types.end())
        return typeIter->second;
 
    return NULL;
}
 
map<string, VuoNodeSet *> VuoCompiler::Environment::getNodeSets(void)
{
    return nodeSetForName;
}
 
VuoCompilerModule *VuoCompiler::Environment::getLibraryModule(const string &libraryModuleName)
{
    map<string, VuoCompilerModule *>::iterator libraryIter = libraryModules.find(libraryModuleName);
    if (libraryIter != libraryModules.end())
        return libraryIter->second;
 
    return nullptr;
}
 
map<string, VuoCompilerModule *> VuoCompiler::Environment::getLibraryModules(void)
{
    return libraryModules;
}
 
VuoCompilerModule * VuoCompiler::Environment::findModule(const string &moduleKey)
{
    map<string, VuoCompilerNodeClass *>::iterator nodeClassIter = nodeClasses.find(moduleKey);
    if (nodeClassIter != nodeClasses.end())
        return nodeClassIter->second;
 
    map<string, VuoCompilerType *>::iterator typeIter = types.find(moduleKey);
    if (typeIter != types.end())
        return typeIter->second;
 
    map<string, VuoCompilerModule *>::iterator libraryIter = libraryModules.find(moduleKey);
    if (libraryIter != libraryModules.end())
        return libraryIter->second;
 
    return NULL;
}
 
VuoNodeSet * VuoCompiler::Environment::findNodeSet(const string &name)
{
 
    map<string, VuoNodeSet *>::iterator nodeSetIter = nodeSetForName.find(name);
    if (nodeSetIter != nodeSetForName.end())
        return nodeSetIter->second;
 
    return NULL;
}
 
void VuoCompiler::Environment::addModuleSearchPath(const string &path, bool shouldWatch)
{
    moduleSearchPaths.push_back(path);
 
    updateModulesAtSearchPath(path);
    updateSourceFilesAtSearchPath(path);
 
    if (shouldWatch)
        startWatchingModuleSearchPath(path);
}
 
vector<string> VuoCompiler::Environment::getModuleSearchPaths(void)
{
    return moduleSearchPaths;
}
 
void VuoCompiler::Environment::addHeaderSearchPath(const string &path)
{
    headerSearchPaths.push_back(path);
}
 
vector<string> VuoCompiler::Environment::getHeaderSearchPaths(void)
{
    return headerSearchPaths;
}
 
void VuoCompiler::Environment::addLibrarySearchPath(const string &path)
{
    librarySearchPaths.push_back(path);
}
 
vector<string> VuoCompiler::Environment::getLibrarySearchPaths(void)
{
    return librarySearchPaths;
}
 
void VuoCompiler::Environment::addFrameworkSearchPath(const string &path)
{
    frameworkSearchPaths.push_back(path);
}
 
vector<string> VuoCompiler::Environment::getFrameworkSearchPaths(void)
{
    return frameworkSearchPaths;
}
 
VuoDirectedAcyclicGraph * VuoCompiler::Environment::getDependencyGraph(void)
{
    return dependencyGraph;
}
 
VuoDirectedAcyclicGraph * VuoCompiler::Environment::getCompositionDependencyGraph(void)
{
    return compositionDependencyGraph;
}
 
void VuoCompiler::Environment::setModuleCachePath(const string &path, bool shouldAddModuleSearchPath)
{
    moduleCachePath = path;
 
    if (shouldAddModuleSearchPath)
    {
        addModuleSearchPath(getCompiledModuleCachePath(), false);
        addModuleSearchPath(getOverriddenCompiledModuleCachePath(), false);
    }
}
 
string VuoCompiler::Environment::getCompiledModuleCachePath(void)
{
    return (moduleCachePath.empty() ? "" : moduleCachePath + "/Modules/" + VuoCompiler::getTargetArch(target));
}
 
string VuoCompiler::Environment::getOverriddenCompiledModuleCachePath(void)
{
    if (moduleCachePath.empty())
        return "";
 
    ostringstream pid;
    pid << getpid();
 
    string dir, moduleCacheDirName, ext;
    VuoFileUtilities::splitPath(moduleCachePath, dir, moduleCacheDirName, ext);
 
    return (VuoFileUtilities::getCachePath() + "/" + pidCacheDirPrefix + pid.str() + "/" + moduleCacheDirName + "/Modules/" + VuoCompiler::getTargetArch(target));
}
 
void VuoCompiler::Environment::addExpatriateSourceFile(const string &sourcePath)
{
    expatriateSourceFiles.push_back(sourcePath);
 
    if (find(moduleSearchPaths.begin(), moduleSearchPaths.end(), "") == moduleSearchPaths.end())
        moduleSearchPaths.push_back("");
 
    auto iter = sourceFilesAtSearchPath.find("");
    if (iter != sourceFilesAtSearchPath.end())
        sourceFilesAtSearchPath.erase(iter);
}
 
void VuoCompiler::Environment::removeExpatriateSourceFile(const string &sourcePath)
{
    for (auto i = expatriateSourceFiles.begin(); i != expatriateSourceFiles.end(); ++i)
    {
        if (VuoFileUtilities::arePathsEqual(*i, sourcePath))
        {
            expatriateSourceFiles.erase(i);
 
            auto iter = sourceFilesAtSearchPath.find("");
            if (iter != sourceFilesAtSearchPath.end())
                sourceFilesAtSearchPath.erase(iter);
 
            break;
        }
    }
}
 
void VuoCompiler::Environment::updateModulesAtSearchPath(const string &path)
{
    if (moduleFilesAtSearchPath.find(path) != moduleFilesAtSearchPath.end())
        return;
 
    set<string> moduleExtensions;
    moduleExtensions.insert("vuonode");
    moduleExtensions.insert("vuonode+");
    moduleExtensions.insert("bc");
    moduleExtensions.insert("bc+");
    set<string> archiveExtensions;
    archiveExtensions.insert("vuonode");
    set<VuoFileUtilities::File *> moduleFiles = VuoFileUtilities::findFilesInDirectory(path, moduleExtensions, archiveExtensions);
 
    map<string, ModuleInfo *> fileForModuleKey;
    for (set<VuoFileUtilities::File *>::iterator i = moduleFiles.begin(); i != moduleFiles.end(); ++i)
    {
        VuoFileUtilities::File *moduleFile = *i;
 
        // Ignore macOS extended attribute storage (a.k.a. xattr, resource fork).
        if (VuoStringUtilities::beginsWith(moduleFile->basename(), "._"))
            continue;
 
        ModuleInfo *m = new ModuleInfo(this, path, moduleFile, false, false);
        fileForModuleKey[m->getModuleKey()] = m;
    }
 
    if (path == getCompiledModuleCachePath())
    {
        for (map<string, ModuleInfo *>::iterator i = fileForModuleKey.begin(); i != fileForModuleKey.end(); )
        {
            ModuleInfo *sourceInfo = listSourceFile(i->first);
            if (! sourceInfo || sourceInfo->isNewerThan(i->second))
            {
                ModuleInfo *m = i->second;
                VuoFileUtilities::deleteFile(m->getFile()->path());
                delete m;
                fileForModuleKey.erase(i++);
            }
            else
                ++i;
        }
    }
 
    moduleFilesAtSearchPath[path] = fileForModuleKey;
}
 
void VuoCompiler::Environment::updateModuleAtSearchPath(const string &moduleSearchPath, const string &moduleRelativePath)
{
    string dir, file, ext;
    VuoFileUtilities::splitPath(moduleRelativePath, dir, file, ext);
 
    set<string> moduleExtensions;
    moduleExtensions.insert(ext);
    set<string> archiveExtensions;
    archiveExtensions.insert("vuonode");
 
    set<VuoFileUtilities::File *> moduleFiles = VuoFileUtilities::findFilesInDirectory(moduleSearchPath, moduleExtensions, archiveExtensions);
 
    for (set<VuoFileUtilities::File *>::iterator i = moduleFiles.begin(); i != moduleFiles.end(); ++i)
    {
        VuoFileUtilities::File *moduleFile = *i;
 
        ModuleInfo *m = new ModuleInfo(this, moduleSearchPath, moduleFile, false, false);
        moduleFilesAtSearchPath[moduleSearchPath][m->getModuleKey()] = m;
    }
}
 
void VuoCompiler::Environment::updateSourceFilesAtSearchPath(const string &path)
{
    map<string, map<string, ModuleInfo *> >::iterator sourceFilesIter = sourceFilesAtSearchPath.find(path);
    if (sourceFilesIter != sourceFilesAtSearchPath.end())
        return;
 
    set<VuoFileUtilities::File *> sourceFiles;
    if (! path.empty())
    {
        set<string> sourceExtensions;
        sourceExtensions.insert("vuo");
        sourceExtensions.insert("fs");
        auto cext = VuoFileUtilities::getCSourceExtensions();
        sourceExtensions.insert(cext.begin(), cext.end());
        sourceFiles = VuoFileUtilities::findFilesInDirectory(path, sourceExtensions, set<string>());
    }
    else
    {
        for (const string &sourcePath : expatriateSourceFiles)
        {
            string dir, file, ext;
            VuoFileUtilities::splitPath(sourcePath, dir, file, ext);
            VuoFileUtilities::File *sourceFile = new VuoFileUtilities::File(dir, file + "." + ext);
            sourceFiles.insert(sourceFile);
        }
    }
 
    map<string, ModuleInfo *> fileForModuleKey;
    for (set<VuoFileUtilities::File *>::iterator i = sourceFiles.begin(); i != sourceFiles.end(); ++i)
    {
        VuoFileUtilities::File *sourceFile = *i;
 
        string dir, moduleKey, ext;
        VuoFileUtilities::splitPath(sourceFile->getRelativePath(), dir, moduleKey, ext);
        bool isSubcomposition = (ext == "vuo");
 
        // Ignore missing expatriateSourceFiles — they might have been deleted in the meantime.
        if (path.empty() && !sourceFile->exists())
            continue;
 
        ModuleInfo *m = new ModuleInfo(this, path, sourceFile, true, isSubcomposition);
        if (fileForModuleKey.find(m->getModuleKey()) != fileForModuleKey.end())
            VUserLog("Warning: Conflicting source files for module %s are installed at %s", m->getModuleKey().c_str(), path.c_str());
        fileForModuleKey[m->getModuleKey()] = m;
 
        if (isSubcomposition)
        {
            DependencyGraphVertex *compositionVertex = DependencyGraphVertex::vertexForDependency(moduleKey, compositionDependencyGraph);
            compositionDependencyGraph->addVertex(compositionVertex);
 
            compositionVertex->setEnvironment(this);
 
            set<string> dependencies = m->getContainedNodeClasses();
            for (set<string>::iterator j = dependencies.begin(); j != dependencies.end(); ++j)
            {
                DependencyGraphVertex *dependencyVertex = DependencyGraphVertex::vertexForDependency(*j, compositionDependencyGraph);
                compositionDependencyGraph->addEdge(compositionVertex, dependencyVertex);
            }
        }
    }
 
    sourceFilesAtSearchPath[path] = fileForModuleKey;
}
 
VuoCompiler::ModuleInfo * VuoCompiler::Environment::listModule(const string &moduleKey)
{
    for (const auto &moduleFiles : moduleFilesAtSearchPath)
    {
        map<string, ModuleInfo *>::const_iterator foundIter = moduleFiles.second.find(moduleKey);
        if (foundIter != moduleFiles.second.end())
            return foundIter->second;
    }
 
    return NULL;
}
 
VuoCompiler::ModuleInfoIterator VuoCompiler::Environment::listModules(const set<string> &moduleKeys)
{
    for (const string &path : moduleSearchPaths)
        updateModulesAtSearchPath(path);
 
    return ModuleInfoIterator(&moduleFilesAtSearchPath, getOverriddenCompiledModuleCachePath(), moduleKeys);
}
 
VuoCompiler::ModuleInfoIterator VuoCompiler::Environment::listAllModules(void)
{
    for (const string &path : moduleSearchPaths)
        updateModulesAtSearchPath(path);
 
    return ModuleInfoIterator(&moduleFilesAtSearchPath, getOverriddenCompiledModuleCachePath());
}
 
VuoCompiler::ModuleInfo * VuoCompiler::Environment::listSourceFile(const string &moduleKey)
{
    for (const auto &sourceFiles : sourceFilesAtSearchPath)
    {
        map<string, ModuleInfo *>::const_iterator foundIter = sourceFiles.second.find(moduleKey);
        if (foundIter != sourceFiles.second.end())
            return foundIter->second;
    }
 
    return NULL;
}
 
VuoCompiler::ModuleInfoIterator VuoCompiler::Environment::listSourceFiles(const set<string> &moduleKeys)
{
    for (const string &path : moduleSearchPaths)
        updateSourceFilesAtSearchPath(path);
 
    return ModuleInfoIterator(&sourceFilesAtSearchPath, "", moduleKeys);
}
 
VuoCompiler::ModuleInfoIterator VuoCompiler::Environment::listAllSourceFiles(void)
{
    for (const string &path : moduleSearchPaths)
        updateSourceFilesAtSearchPath(path);
 
    return ModuleInfoIterator(&sourceFilesAtSearchPath, "");
}
 
vector<string> VuoCompiler::Environment::getBuiltInModuleSearchPaths(void)
{
    vector<string> builtInModuleSearchPaths;
 
    string vuoFrameworkPath = getVuoFrameworkPath();
    if (! vuoFrameworkPath.empty())
    {
        builtInModuleSearchPaths.push_back(vuoFrameworkPath + "/Modules");
    }
    else
    {
        builtInModuleSearchPaths.push_back(VUO_BUILD_DIR "/library");
        builtInModuleSearchPaths.push_back(VUO_BUILD_DIR "/node");
        builtInModuleSearchPaths.push_back(VUO_BUILD_DIR "/type");
        builtInModuleSearchPaths.push_back(VUO_BUILD_DIR "/type/list");
    }
 
    return builtInModuleSearchPaths;
}
 
vector<string> VuoCompiler::Environment::getBuiltInHeaderSearchPaths(void)
{
    vector<string> builtInHeaderSearchPaths;
 
    string vuoFrameworkPath = getVuoFrameworkPath();
    if (! vuoFrameworkPath.empty())
    {
        builtInHeaderSearchPaths.push_back(vuoFrameworkPath + "/Frameworks/llvm.framework/Versions/A/Headers/lib/c++/v1");
        builtInHeaderSearchPaths.push_back(vuoFrameworkPath + "/Headers");
        builtInHeaderSearchPaths.push_back(vuoFrameworkPath + "/Headers/macos");          // system headers installed by Xcode Command Line Tools
        builtInHeaderSearchPaths.push_back(vuoFrameworkPath + "/Headers/macos/pthread");  //
    }
    else
    {
        builtInHeaderSearchPaths.push_back(LLVM_ROOT "/include/c++/v1");
        builtInHeaderSearchPaths.push_back(VUO_SOURCE_DIR "/library");
        builtInHeaderSearchPaths.push_back(VUO_SOURCE_DIR "/node");
        builtInHeaderSearchPaths.push_back(VUO_SOURCE_DIR "/type");
        builtInHeaderSearchPaths.push_back(VUO_SOURCE_DIR "/type/list");
        builtInHeaderSearchPaths.push_back(VUO_SOURCE_DIR "/runtime");
        builtInHeaderSearchPaths.push_back(JSONC_ROOT "/include");
    }
 
    return builtInHeaderSearchPaths;
}
 
vector<string> VuoCompiler::Environment::getBuiltInLibrarySearchPaths(void)
{
    vector<string> builtInLibrarySearchPaths;
 
    string vuoFrameworkPath = getVuoFrameworkPath();
    if (! vuoFrameworkPath.empty())
    {
        builtInLibrarySearchPaths.push_back(vuoFrameworkPath + "/Modules");
 
        // Ensure we (statically) link to our OpenSSL build when generating Vuo.framework's built-in module cache.
        builtInLibrarySearchPaths.push_back(OPENSSL_ROOT "/lib");
    }
    else
    {
        builtInLibrarySearchPaths.push_back(VUO_BUILD_DIR "/library");
        builtInLibrarySearchPaths.push_back(VUO_BUILD_DIR "/node");
        builtInLibrarySearchPaths.push_back(VUO_BUILD_DIR "/type");
        builtInLibrarySearchPaths.push_back(VUO_BUILD_DIR "/type/list");
        builtInLibrarySearchPaths.push_back(VUO_BUILD_DIR "/runtime");
 
        vector<string> conanLibDirs = VuoStringUtilities::split(CONAN_LIBRARY_PATHS, ';');
        builtInLibrarySearchPaths.insert(builtInLibrarySearchPaths.end(), conanLibDirs.begin(), conanLibDirs.end());
    }
 
    return builtInLibrarySearchPaths;
}
 
vector<string> VuoCompiler::Environment::getBuiltInFrameworkSearchPaths(void)
{
    vector<string> builtInFrameworkSearchPaths;
 
    string vuoFrameworkPath = getVuoFrameworkPath();
    if (! vuoFrameworkPath.empty())
    {
        builtInFrameworkSearchPaths.push_back(vuoFrameworkPath + "/Modules/");
        builtInFrameworkSearchPaths.push_back(vuoFrameworkPath + "/Frameworks/");
    }
 
    return builtInFrameworkSearchPaths;
}
 
void VuoCompiler::Environment::startWatchingModuleSearchPath(const string &moduleSearchPath)
{
    VuoFileWatcher *watcher = new VuoFileWatcher(this, moduleSearchPath);
    moduleSearchPathWatchers.insert(watcher);
}
 
void VuoCompiler::Environment::stopWatchingModuleSearchPaths(void)
{
    for (set<VuoFileWatcher *>::iterator i = moduleSearchPathWatchers.begin(); i != moduleSearchPathWatchers.end(); ++i)
        delete *i;
 
    moduleSearchPathWatchers.clear();
}
 
void VuoCompiler::Environment::fileChanged(const string &moduleSearchPath)
{
    dispatch_sync(moduleSearchPathContentsChangedQueue, ^{
                      moduleSearchPathContentsChanged(moduleSearchPath);
                  });
}
 
void VuoCompiler::Environment::moduleSearchPathContentsChanged(const string &moduleSearchPath)
{
    //VLog("                 E=%p -- %s", this, moduleSearchPath.c_str());
    VuoCompiler *compilerForLoading = new VuoCompiler(moduleSearchPath + "/unused");
 
    __block set<string> modulesAdded;
    __block set<string> modulesModifed;
    __block set<string> modulesRemoved;
    __block set<string> compositionsAdded;
    __block set<string> compositionsModifed;
    __block set<string> compositionsRemoved;
 
    dispatch_sync(environmentQueue, ^{
 
                      // Remove the old file records from the environment.
 
                      map<string, ModuleInfo *> oldModules;
                      map<string, ModuleInfo *> oldCompositions;
 
                      map<string, map<string, ModuleInfo *> >::iterator mf = moduleFilesAtSearchPath.find(moduleSearchPath);
                      if (mf != moduleFilesAtSearchPath.end())
                      {
                          for (map<string, ModuleInfo *>::iterator j = mf->second.begin(); j != mf->second.end(); ++j)
                          {
                              oldModules[j->first] = j->second;
                          }
 
                          moduleFilesAtSearchPath.erase(mf);
                      }
 
                      map<string, map<string, ModuleInfo *> >::iterator cf = sourceFilesAtSearchPath.find(moduleSearchPath);
                      if (cf != sourceFilesAtSearchPath.end())
                      {
                          for (map<string, ModuleInfo *>::iterator j = cf->second.begin(); j != cf->second.end(); ++j)
                          {
                              oldCompositions[j->first] = j->second;
 
                              VuoDirectedAcyclicGraph::Vertex *vertex = compositionDependencyGraph->findVertex(j->first);
                              compositionDependencyGraph->removeVertex(vertex);
                          }
 
                          sourceFilesAtSearchPath.erase(cf);
                      }
 
                      // Rebuild the file records based on the directory contents.
 
                      updateModulesAtSearchPath(moduleSearchPath);
                      updateSourceFilesAtSearchPath(moduleSearchPath);
 
                      // Remove any overrides for source files that have been modified or removed.
 
                      auto omf = moduleFilesAtSearchPath.find(getOverriddenCompiledModuleCachePath());
                      if (omf != moduleFilesAtSearchPath.end())
                      {
                          for (auto oldComposition : oldCompositions)
                          {
                              for (auto i = omf->second.begin(); i != omf->second.end(); ++i)
                              {
                                  if (i->first == oldComposition.first)
                                  {
                                      VuoFileUtilities::deleteFile(i->second->getFile()->path());
                                      omf->second.erase(i);
                                      break;
                                  }
                              }
                          }
                      }
 
                      // Compare the old and new file records to see what has changed.
 
                      mf = moduleFilesAtSearchPath.find(moduleSearchPath);
                      if (mf != moduleFilesAtSearchPath.end())
                      {
                          for (map<string, ModuleInfo *>::iterator n = mf->second.begin(); n != mf->second.end(); ++n)
                          {
                              string moduleKey = n->first;
 
                              map<string, ModuleInfo *>::iterator o = oldModules.find(moduleKey);
                              if (o != oldModules.end())
                              {
                                  if (n->second->isNewerThan(o->second))
                                  {
                                      modulesModifed.insert(moduleKey);
                                  }
                                  else
                                  {
                                      n->second->setAttempted(o->second->getAttempted());
                                  }
 
                                  delete o->second;
                                  oldModules.erase(o);
                              }
                              else
                              {
                                  modulesAdded.insert(moduleKey);
                              }
                          }
                      }
 
                      cf = sourceFilesAtSearchPath.find(moduleSearchPath);
                      if (cf != sourceFilesAtSearchPath.end())
                      {
                          for (map<string, ModuleInfo *>::iterator n = cf->second.begin(); n != cf->second.end(); ++n)
                          {
                              string moduleKey = n->first;
 
                              map<string, ModuleInfo *>::iterator o = oldCompositions.find(moduleKey);
                              if (o != oldCompositions.end())
                              {
                                  if (n->second->isNewerThan(o->second))
                                  {
                                      compositionsModifed.insert(moduleKey);
                                  }
                                  else
                                  {
                                      n->second->setAttempted(o->second->getAttempted());
                                      n->second->setSourceCode(o->second->getSourceCode());
                                  }
 
                                  delete o->second;
                                  oldCompositions.erase(o);
                              }
                              else
                              {
                                  compositionsAdded.insert(moduleKey);
                              }
                          }
                      }
 
                      for (map<string, ModuleInfo *>::iterator o = oldModules.begin(); o != oldModules.end(); ++o)
                      {
                          delete o->second;
                          modulesRemoved.insert(o->first);
                      }
 
                      for (map<string, ModuleInfo *>::iterator o = oldCompositions.begin(); o != oldCompositions.end(); ++o)
                      {
                          delete o->second;
                          compositionsRemoved.insert(o->first);
                      }
 
                      compilerForLoading->loadModulesAndSources(modulesAdded, modulesModifed, modulesRemoved,
                                                                compositionsAdded, compositionsModifed, compositionsRemoved,
                                                                false, false, this, nullptr, nullptr, "");
                  });
 
    delete compilerForLoading;
}
 
void VuoCompiler::Environment::moduleFileChanged(const string &modulePath, const string &moduleSourceCode,
                                                 std::function<void(void)> moduleLoadedCallback,
                                                 VuoCompiler *compiler, VuoCompilerIssues *issues)
{
    //VLog("                 E=%p -- %s", this, modulePath.c_str());
    dispatch_sync(environmentQueue, ^{
 
                      string moduleDir, moduleKey, ext;
                      VuoFileUtilities::splitPath(modulePath, moduleDir, moduleKey, ext);
                      VuoFileUtilities::canonicalizePath(moduleDir);
 
                      // Remove the old file record from the environment.
 
                      bool foundOldModule = false;
                      auto moduleSearchPathIter = moduleFilesAtSearchPath.find(moduleDir);
                      if (moduleSearchPathIter != moduleFilesAtSearchPath.end())
                      {
                          auto moduleIter = moduleSearchPathIter->second.find(moduleKey);
                          if (moduleIter != moduleSearchPathIter->second.end())
                          {
                              delete moduleIter->second;
                              moduleSearchPathIter->second.erase(moduleIter);
                              foundOldModule = true;
                          }
                      }
 
                      // Update the file record for the module by re-checking the file.
 
                      updateModuleAtSearchPath(moduleDir, moduleKey + "." + ext);
 
                      // Compare the old and new file records to see how the module has changed.
 
                      bool foundNewModule = false;
                      moduleSearchPathIter = moduleFilesAtSearchPath.find(moduleDir);
                      if (moduleSearchPathIter != moduleFilesAtSearchPath.end())
                      {
                          auto moduleIter = moduleSearchPathIter->second.find(moduleKey);
                          if (moduleIter != moduleSearchPathIter->second.end())
                          {
                              foundNewModule = true;
                          }
                      }
 
                      set<string> modulesAdded;
                      set<string> modulesModified;
                      set<string> modulesRemoved;
 
                      if ((foundOldModule || VuoFileUtilities::arePathsEqual(moduleDir, getOverriddenCompiledModuleCachePath())) && foundNewModule)
                      {
                          modulesModified.insert(moduleKey);
                      }
                      else if (! foundOldModule && foundNewModule)
                      {
                          modulesAdded.insert(moduleKey);
                      }
                      else if (foundOldModule && ! foundNewModule)
                      {
                          modulesRemoved.insert(moduleKey);
                      }
 
                      compiler->loadModulesAndSources(modulesAdded, modulesModified, modulesRemoved,
                                                      set<string>(), set<string>(), set<string>(),
                                                      false, false, this, issues, moduleLoadedCallback, moduleSourceCode);
                  });
 
}
 
void VuoCompiler::Environment::notifyCompilers(const set<VuoCompilerModule *> &modulesAdded,
                                               const set< pair<VuoCompilerModule *, VuoCompilerModule *> > &modulesModified,
                                               const set<VuoCompilerModule *> &modulesRemoved, VuoCompilerIssues *issues,
                                               bool oldModulesInvalidated)
{
    if (! (modulesAdded.empty() && modulesModified.empty() && modulesRemoved.empty() && issues->isEmpty()) )
    {
        set< pair<VuoCompilerModule *, VuoCompilerModule *> > invalidatedModulesModified;
        set<VuoCompilerModule *> invalidatedModulesRemoved;
        if (oldModulesInvalidated)
        {
            invalidatedModulesModified = modulesModified;
            invalidatedModulesRemoved = modulesRemoved;
        }
 
        VuoCompilerDelegate::LoadedModulesData *delegateData = new VuoCompilerDelegate::LoadedModulesData(invalidatedModulesModified, invalidatedModulesRemoved, issues);
 
        map<string, VuoCompilerModule *> modulesAddedMap;
        map<string, pair<VuoCompilerModule *, VuoCompilerModule *> > modulesModifiedMap;
        map<string, VuoCompilerModule *> modulesRemovedMap;
        for (VuoCompilerModule *m : modulesAdded)
            modulesAddedMap[m->getPseudoBase()->getModuleKey()] = m;
        for (pair<VuoCompilerModule *, VuoCompilerModule *> m : modulesModified)
            modulesModifiedMap[m.first->getPseudoBase()->getModuleKey()] = m;
        for (VuoCompilerModule *m : modulesRemoved)
            modulesRemovedMap[m->getPseudoBase()->getModuleKey()] = m;
 
        dispatch_sync(compilersToNotifyQueue, ^{
                          for (set<VuoCompiler *>::iterator i = compilersToNotify.begin(); i != compilersToNotify.end(); ++i) {
                              delegateData->retain();
                          }
                          for (set<VuoCompiler *>::iterator i = compilersToNotify.begin(); i != compilersToNotify.end(); ++i) {
                              (*i)->loadedModules(modulesAddedMap, modulesModifiedMap, modulesRemovedMap, issues, delegateData, this);
                          }
                      });
    }
    else
    {
        delete issues;
    }
}
 
set<VuoCompilerModule *> VuoCompiler::Environment::loadCompiledModules(const set<string> &moduleKeys, const map<string, string> &sourceCodeForModule)
{
    ModuleInfoIterator modulesToLoadIter = listModules(moduleKeys);
    set<VuoCompilerModule *> modulesLoaded;
 
    ModuleInfo *moduleInfo;
    while ((moduleInfo = modulesToLoadIter.next()))
    {
        string moduleKey = moduleInfo->getModuleKey();
 
        // Skip the module if its file is not in this environment, if the module has already been loaded,
        // or if the compiler previously tried to load the module and it failed.
        if (moduleInfo->getEnvironment() != this || findModule(moduleKey) || moduleInfo->getAttempted())
            continue;
 
        moduleInfo->setAttempted(true);
 
        // Actually load the module.
        VuoCompilerModule *module = loadModule(moduleInfo);
 
        if (module)
        {
            modulesLoaded.insert(module);
            addToDependencyGraph(module);
            modulesChanged();
 
            // For a compiled subcomposition or other source file, store its source code in the VuoCompilerNodeClass.
            string searchPath = moduleInfo->getSearchPath();
            if (VuoFileUtilities::arePathsEqual(searchPath, getCompiledModuleCachePath()) ||
                    VuoFileUtilities::arePathsEqual(searchPath, getOverriddenCompiledModuleCachePath()))
            {
                VuoCompilerNodeClass *nodeClass = dynamic_cast<VuoCompilerNodeClass *>(module);
                if (nodeClass)
                {
                    ModuleInfo *sourceInfo = listSourceFile(moduleKey);
                    if (sourceInfo)
                        nodeClass->setSourcePath( sourceInfo->getFile()->path() );
 
                    auto sourceCodeIter = sourceCodeForModule.find(moduleKey);
                    if (sourceCodeIter != sourceCodeForModule.end())
                        nodeClass->setSourceCode( sourceCodeIter->second );
                }
            }
        }
    }
 
    return modulesLoaded;
}
 
set<dispatch_group_t> VuoCompiler::Environment::loadSpecializedModules(const set<string> &moduleKeys,
                                                                       VuoCompiler *compiler, dispatch_queue_t llvmQueue)
{
    set<dispatch_group_t > loadingGroups;
 
    for (string moduleKey : moduleKeys)
    {
        // Skip if it's not a node class.
 
        if (moduleKey.find(".") == string::npos ||
                VuoStringUtilities::endsWith(moduleKey, ".framework") ||
                VuoStringUtilities::endsWith(moduleKey, ".dylib"))
            continue;
 
        // Skip the module if it's already been loaded.
 
        if (findModule(moduleKey))
            continue;
 
        // Skip the module if it's in the process of being loaded, but have the caller wait for it to finish loading.
 
        map<string, dispatch_group_t>::iterator iter = specializedModulesLoading.find(moduleKey);
        if (iter != specializedModulesLoading.end())
        {
            loadingGroups.insert(iter->second);
            dispatch_retain(iter->second);
            continue;
        }
 
        dispatch_group_t loadingGroup = dispatch_group_create();
        specializedModulesLoading[moduleKey] = loadingGroup;
        loadingGroups.insert(loadingGroup);
 
        // Generate the module.
        // This is done asynchronously since VuoCompilerSpecializedNodeClass::newNodeClass() needs to use environmentQueue
        // to compile the generated C code.
 
        dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
        dispatch_group_async(loadingGroup, queue, ^{
            VuoNodeClass *baseNodeClass = nullptr;
            try
            {
                baseNodeClass = VuoCompilerSpecializedNodeClass::newNodeClass(moduleKey, compiler, llvmQueue);
            }
            catch (VuoCompilerException &e)
            {
                VUserLog("Error: %s", e.what());
            }
 
            if (baseNodeClass)
            {
                VuoCompilerSpecializedNodeClass *specNodeClass = static_cast<VuoCompilerSpecializedNodeClass *>(baseNodeClass->getCompiler());
                compiler->loadNodeClassGeneratedAtRuntime(specNodeClass, this);
 
                set<string> dependencies = specNodeClass->getDependencies();
                if (!dependencies.empty())
                    compiler->loadModulesIfNeeded(dependencies);
            }
 
            dispatch_sync(environmentQueue, ^{
                specializedModulesLoading.erase(moduleKey);
            });
        });
    }
 
    return loadingGroups;
}
 
set<dispatch_group_t> VuoCompiler::Environment::compileModulesFromSourceCode(const set<string> &moduleKeys, bool shouldRecompileIfUnchanged)
{
    ModuleInfoIterator modulesToLoadIter = listSourceFiles(moduleKeys);
 
    int environmentIndex = sharedEnvironments[target].size();
    for (int i = 0; i < sharedEnvironments[target].size(); ++i)
        if (this == sharedEnvironments[target].at(i).at(0))
            environmentIndex = i;
 
    set<dispatch_group_t> sourcesLoading;
    int sourcesEnqueued = 0;
    ModuleInfo *sourceInfo;
    while ((sourceInfo = modulesToLoadIter.next()))
    {
        string moduleKey = sourceInfo->getModuleKey();
 
        dispatch_group_t loadingGroup = sourceInfo->getLoadingGroup();
        sourcesLoading.insert(loadingGroup);
 
        // Skip compiling if the source file has already been scheduled for compilation.
        // Either its compilation is in progress or it failed to compile.
 
        if (sourceInfo->getAttempted())
            continue;
 
        // Skip compiling if the compiled module is up-to-date.
 
        string sourceCode = sourceInfo->getSourceCode();
 
        if (! shouldRecompileIfUnchanged)
        {
            VuoCompilerNodeClass *existingNodeClass = getNodeClass(moduleKey);
            if (existingNodeClass && existingNodeClass->getSourceCode() == sourceCode)
                continue;
        }
 
        // Enqueue the source file to be compiled.
 
        sourceInfo->setAttempted(true);
 
        dispatch_group_enter(loadingGroup);
        dispatch_group_enter(moduleSourceCompilersExistGlobally);
 
        VuoModuleCompilationQueue::Item *queueItem = new VuoModuleCompilationQueue::Item();
        queueItem->moduleKey = moduleKey;
        queueItem->sourcePath = sourceInfo->getFile()->path();
        queueItem->sourceCode = sourceCode;
        queueItem->sourceFile = sourceInfo->getFile();
        queueItem->cachedModulesPath = sourceInfo->isSourceCodeOverridden() ? getOverriddenCompiledModuleCachePath() : getCompiledModuleCachePath();
        queueItem->compiledModulePath = queueItem->cachedModulesPath + "/" + moduleKey + ".vuonode";
        queueItem->loadingGroup = loadingGroup;
        queueItem->priority = { environmentIndex, sourceInfo->getLongestDownstreamPath() };
        moduleCompilationQueue->enqueue(queueItem);
        ++sourcesEnqueued;
    }
 
    // Compile each enqueued source file. This is done asynchronously for several reasons:
    //   - To avoid environmentQueue calling compiler code calling environmentQueue.
    //   - To compile dependencies that were enqueued later while a compilation that was enqueued earlier waits.
    //   - To be more efficient when compiling multiple source files.
 
    dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
    dispatch_async(queue, ^{
        for (int i = 0; i < sourcesEnqueued; ++i)
        {
            __block VuoModuleCompilationQueue::Item *queueItem = moduleCompilationQueue->next();
            VUserLog("Compiling %s", queueItem->moduleKey.c_str());
 
            dispatch_async(queue, ^{
                try
                {
                    VuoFileUtilities::makeDir(queueItem->cachedModulesPath);
                }
                catch (VuoException &e)
                {
                    VuoCompilerIssue issue(VuoCompilerIssue::Error, "compiling subcomposition", "", "Couldn't create cached modules folder", e.what());
                    VuoCompilerIssues *issues = new VuoCompilerIssues(issue);
                    notifyCompilers(set<VuoCompilerModule *>(), set< pair<VuoCompilerModule *, VuoCompilerModule *> >(), set<VuoCompilerModule *>(), issues, false);
                }
 
                VuoCompiler *compiler = new VuoCompiler(queueItem->sourcePath, target);
                compiler->setLoadAllModules(false);
 
                VuoModuleCompilationQueue::Item *queueItemForCallback = queueItem;
                auto moduleLoadedCallback = [=](){
                    dispatch_group_leave(queueItemForCallback->loadingGroup);
                    moduleCompilationQueue->completed(queueItemForCallback);
                };
 
                string ext = queueItem->sourceFile->extension();
                if (VuoFileUtilities::isIsfSourceExtension(ext))
                {
                    VuoModuleCompiler *moduleCompiler = NULL;
                    try
                    {
                        moduleCompiler = VuoModuleCompiler::newModuleCompiler("isf", queueItem->moduleKey, queueItem->sourceFile);
                    }
                    catch (VuoException &e)
                    {
                        VuoCompilerIssues *issues = new VuoCompilerIssues(VuoCompilerIssue(VuoCompilerIssue::Error, "compiling ISF module", queueItem->sourcePath, "", e.what()));
                        notifyCompilers(set<VuoCompilerModule *>(), set< pair<VuoCompilerModule *, VuoCompilerModule *> >(), set<VuoCompilerModule *>(), issues, false);
                    }
 
                    if (moduleCompiler)
                    {
                        moduleCompiler->overrideSourceCode(queueItem->sourceCode, queueItem->sourceFile);
 
                        auto getType = [&compiler] (const string &moduleKey) { return compiler->getType(moduleKey); };
                        VuoCompilerIssues *issues = new VuoCompilerIssues;
                        Module *module = moduleCompiler->compile(getType, llvmQueue, issues);
 
                        if (module)
                        {
                            dispatch_sync(llvmQueue, ^{
                                setTargetForModule(module, target);
                                writeModuleToBitcode(module, queueItem->compiledModulePath);
                            });
                        }
                        else
                        {
                            issues->setFilePathIfEmpty(queueItem->sourcePath);
                        }
 
                        moduleFileChanged(queueItem->compiledModulePath, queueItem->sourceCode, moduleLoadedCallback, compiler, issues);
                    }
                    else
                        moduleLoadedCallback();
                }
                else if (VuoFileUtilities::isCSourceExtension(ext) && ! queueItem->cachedModulesPath.empty())
                {
                    VuoCompilerIssues *issues = new VuoCompilerIssues;
 
                    try
                    {
                        compiler->compileModule(queueItem->sourcePath, queueItem->compiledModulePath, vector<string>());
                    }
                    catch (VuoCompilerException &e)
                    {
                        if (issues != e.getIssues())
                            issues->append(e.getIssues());
 
                        issues->setFilePathIfEmpty(queueItem->sourcePath);
                    }
 
                    moduleFileChanged(queueItem->compiledModulePath, queueItem->sourceCode, moduleLoadedCallback, compiler, issues);
                }
                else
                {
                    VuoCompilerIssues *issues = new VuoCompilerIssues;
 
                    try
                    {
                        VuoCompilerComposition *composition = VuoCompilerComposition::newCompositionFromGraphvizDeclaration(queueItem->sourceCode, compiler);
 
                        Module *module = compiler->compileCompositionToModule(composition, queueItem->moduleKey, false, issues);
                        if (! module)
                            throw VuoCompilerException(issues, false);
 
                        dispatch_sync(llvmQueue, ^{
                            setTargetForModule(module, target);
                            writeModuleToBitcode(module, queueItem->compiledModulePath);
                        });
 
                        VuoComposition *baseComposition = composition->getBase();
                        delete composition;
                        delete baseComposition;
                    }
                    catch (VuoCompilerException &e)
                    {
                        if (issues != e.getIssues())
                            issues->append(e.getIssues());
 
                        issues->setFilePathIfEmpty(queueItem->sourcePath);
                    }
 
                    moduleFileChanged(queueItem->compiledModulePath, queueItem->sourceCode, moduleLoadedCallback, compiler, issues);
                }
 
                delete compiler;
                dispatch_group_leave(moduleSourceCompilersExistGlobally);
            });
        }
    });
 
    return sourcesLoading;
}
 
set<VuoCompilerModule *> VuoCompiler::Environment::unloadCompiledModules(const set<string> &moduleKeys)
{
    set<VuoCompilerModule *> modulesUnloaded;
 
    for (set<string>::const_iterator i = moduleKeys.begin(); i != moduleKeys.end(); ++i)
    {
        string moduleKey = *i;
        VuoCompilerModule *module = NULL;
 
        map<string, VuoCompilerNodeClass *>::iterator nodeClassIter = nodeClasses.find(moduleKey);
        if (nodeClassIter != nodeClasses.end())
        {
            module = nodeClassIter->second;
            nodeClasses.erase(nodeClassIter);
        }
        else
        {
            map<string, VuoCompilerType *>::iterator typeIter = types.find(moduleKey);
            if (typeIter != types.end())
            {
                module = typeIter->second;
                types.erase(typeIter);
            }
            else
            {
                map<string, VuoCompilerModule *>::iterator libraryModuleIter = libraryModules.find(moduleKey);
                if (libraryModuleIter != libraryModules.end())
                {
                    module = libraryModuleIter->second;
                    libraryModules.erase(libraryModuleIter);
                }
            }
        }
 
        if (module)
        {
            modulesUnloaded.insert(module);
            removeFromDependencyGraph(module);
            modulesChanged();
        }
    }
 
    return modulesUnloaded;
}
 
void VuoCompiler::Environment::deleteModulesCompiledFromSourceCode(const set<string> &moduleKeys)
{
    for (set<string>::const_iterator i = moduleKeys.begin(); i != moduleKeys.end(); ++i)
    {
        string moduleKey = *i;
 
        map<string, ModuleInfo *>::iterator iter = moduleFilesAtSearchPath[getCompiledModuleCachePath()].find(moduleKey);
        if (iter != moduleFilesAtSearchPath[getCompiledModuleCachePath()].end())
            VuoFileUtilities::deleteFile(iter->second->getFile()->path());
    }
}
 
VuoCompilerModule * VuoCompiler::Environment::loadModule(ModuleInfo *moduleInfo)
{
    string moduleKey = moduleInfo->getModuleKey();
 
    // Skip certain LLVM modules that definitely aren't Vuo modules to avoid adding struct types defined in them to the LLVM
    // context, resulting in mismatched struct types in code generation (e.g. %struct.NodeContext and %struct.NodeContext.1).
    if (VuoStringUtilities::beginsWith(moduleKey, "libVuo"))
        return NULL;
 
    // Don't try to load single-target parts
    // (such as those found in `build/test/TestControlAndTelemetry`),
    // since they just fail and pollute the logs.
    if (VuoStringUtilities::endsWith(moduleKey, "-x86_64")
     || VuoStringUtilities::endsWith(moduleKey, "-arm64"))
        return nullptr;
 
    __block size_t inputDataBytes;
    __block char *rawInputData;
    dispatch_sync(llvmQueue, ^{
        try
        {
            rawInputData = moduleInfo->getFile()->getContentsAsRawData(inputDataBytes);
        }
        catch (VuoException &e)
        {
            rawInputData = NULL;
            VUserLog("Warning: Couldn't load module '%s'. Its file may have been deleted. (%s)", moduleKey.c_str(), e.what());
        }
    });
    if (! rawInputData)
        return NULL;
 
    char *processedInputData;
#if VUO_PRO
    processedInputData = loadModule_Pro0(moduleInfo, moduleKey, inputDataBytes, rawInputData);
#else
    processedInputData = rawInputData;
#endif
 
    Module *module = NULL;
    set<string> moduleArchs;
    bool moduleParseError = !processedInputData;
    if (!moduleParseError)
    {
        string moduleReadError;
        string arch = VuoCompiler::getTargetArch(target);
        VuoLog_status("Loading module \"%s\" (%s)", moduleKey.c_str(), arch.c_str());
        module = readModuleFromBitcodeData(processedInputData, inputDataBytes, arch, moduleArchs, moduleReadError);
        VuoLog_status(NULL);
        free(processedInputData);
 
        if (!module)
        {
            moduleParseError = true;
 
            if (VuoFileUtilities::arePathsEqual(moduleInfo->getSearchPath(), getCompiledModuleCachePath()))
                VuoFileUtilities::deleteFile(moduleInfo->getFile()->path());
            else
                VUserLog("Error: Couldn't load module '%s' into %s environment: %s.", moduleKey.c_str(), arch.c_str(), moduleReadError.c_str());
        }
    }
 
    if (!moduleParseError)
    {
        string modulePath;
        if (! moduleInfo->getFile()->isInArchive())
            modulePath = moduleInfo->getFile()->path();
 
        VuoCompilerCompatibility moduleCompatibility = (VuoFileUtilities::arePathsEqual(moduleInfo->getSearchPath(), getCompiledModuleCachePath()) ?
                                                            VuoCompilerCompatibility::compatibilityWithAnySystem() :
                                                            VuoCompilerCompatibility::compatibilityWithArchitectures(moduleArchs));
 
        __block VuoCompilerModule *compilerModule;
        dispatch_sync(llvmQueue, ^{
                          compilerModule = VuoCompilerModule::newModule(moduleKey, module, modulePath, moduleCompatibility);
                      });
 
        if (compilerModule)
        {
            if (dynamic_cast<VuoCompilerNodeClass *>(compilerModule))
                nodeClasses[moduleKey] = static_cast<VuoCompilerNodeClass *>(compilerModule);
            else if (dynamic_cast<VuoCompilerType *>(compilerModule))
                types[moduleKey] = static_cast<VuoCompilerType *>(compilerModule);
            else
                libraryModules[moduleKey] = compilerModule;
 
            VuoNodeSet *nodeSet = VuoNodeSet::createNodeSetForModule(moduleInfo->getFile());
            if (nodeSet)
            {
                map<string, VuoNodeSet *>::iterator nodeSetIter = nodeSetForName.find(nodeSet->getName());
                if (nodeSetIter == nodeSetForName.end())
                {
                    nodeSetForName[nodeSet->getName()] = nodeSet;
                }
                else
                {
                    delete nodeSet;
                    nodeSet = nodeSetIter->second;
                }
                compilerModule->getPseudoBase()->setNodeSet(nodeSet);
            }
 
#if VUO_PRO
            loadModule_Pro1(rawInputData, processedInputData, compilerModule);
#endif
 
            compilerModule->setBuiltIn( isBuiltInOriginal() );
 
            return compilerModule;
        }
        else
        {
            destroyLlvmModule(module);
        }
    }
 
    return NULL;
}
 
void VuoCompiler::Environment::replaceNodeClass(VuoCompilerNodeClass *newNodeClass)
{
    string moduleKey = newNodeClass->getBase()->getModuleKey();
 
    VuoCompilerNodeClass *oldNodeClass = nodeClasses[moduleKey];
    if (oldNodeClass)
    {
        removeFromDependencyGraph(oldNodeClass);
        destroyModule(oldNodeClass);
    }
 
    nodeClasses[moduleKey] = newNodeClass;
    addToDependencyGraph(newNodeClass);
    modulesChanged();
}
 
void VuoCompiler::Environment::addToDependencyGraph(VuoCompilerModule *module)
{
    DependencyGraphVertex *vertex = DependencyGraphVertex::vertexForDependency(module->getPseudoBase()->getModuleKey(), dependencyGraph);
    dependencyGraph->addVertex(vertex);
 
    vertex->setEnvironment(this);
 
    set<string> dependencies = module->getDependencies();
    for (set<string>::iterator i = dependencies.begin(); i != dependencies.end(); ++i)
    {
        DependencyGraphVertex *depVertex = DependencyGraphVertex::vertexForDependency(*i, dependencyGraph);
        dependencyGraph->addEdge(vertex, depVertex);
    }
}
 
void VuoCompiler::Environment::removeFromDependencyGraph(VuoCompilerModule *module)
{
    DependencyGraphVertex *vertex = DependencyGraphVertex::vertexForDependency(module->getPseudoBase()->getModuleKey(), dependencyGraph);
    dependencyGraph->removeVertex(vertex);
}
 
void VuoCompiler::Environment::reifyPortTypes(const map<string, VuoCompilerType *> &inheritedTypes)
{
    map<string, VuoCompilerType *> availableTypes = inheritedTypes;
    availableTypes.insert(types.begin(), types.end());
 
    for (map<string, VuoCompilerNodeClass *>::const_iterator i = nodeClasses.begin(); i != nodeClasses.end(); ++i)
    {
        VuoNodeClass *nodeClass = i->second->getBase();
 
        vector<VuoPortClass *> inputPortClasses = nodeClass->getInputPortClasses();
        vector<VuoPortClass *> outputPortClasses = nodeClass->getOutputPortClasses();
        vector<VuoPortClass *> portClasses;
        portClasses.insert(portClasses.end(), inputPortClasses.begin(), inputPortClasses.end());
        portClasses.insert(portClasses.end(), outputPortClasses.begin(), outputPortClasses.end());
 
        for (vector<VuoPortClass *>::iterator j = portClasses.begin(); j != portClasses.end(); ++j)
        {
            VuoCompilerPortClass *portClass = static_cast<VuoCompilerPortClass *>((*j)->getCompiler());
            VuoType *baseType = portClass->getDataVuoType();
 
            if (baseType && ! baseType->hasCompiler())
            {
                string typeName = baseType->getModuleKey();
                VuoCompilerType *reifiedType = NULL;
 
                VuoGenericType *genericType = dynamic_cast<VuoGenericType *>(baseType);
                if (genericType)
                {
                    reifiedType = VuoCompilerGenericType::newGenericType(genericType, availableTypes);
                    if (reifiedType) {
                        genericTypes.insert( static_cast<VuoCompilerGenericType *>(reifiedType) );
                    }
                }
                else
                {
                    map<string, VuoCompilerType *>::iterator reifiedTypeIter = availableTypes.find(typeName);
                    if (reifiedTypeIter != availableTypes.end())
                    {
                        delete baseType;
                        reifiedType = reifiedTypeIter->second;
                    }
                }
 
                if (reifiedType) {
                    portClass->setDataVuoType(reifiedType->getBase());
                }
            }
        }
 
        vector<VuoCompilerTriggerDescription *> triggers = nodeClass->getCompiler()->getTriggerDescriptions();
        for (vector<VuoCompilerTriggerDescription *>::iterator j = triggers.begin(); j != triggers.end(); ++j)
        {
            VuoCompilerTriggerDescription *trigger = *j;
            VuoType *baseType = trigger->getDataType();
 
            if (baseType && ! baseType->hasCompiler())
            {
                string typeName = baseType->getModuleKey();
                map<string, VuoCompilerType *>::iterator reifiedTypeIter = availableTypes.find(typeName);
                if (reifiedTypeIter != availableTypes.end())
                {
                    delete baseType;
                    VuoCompilerType *reifiedType = reifiedTypeIter->second;
                    trigger->setDataType(reifiedType->getBase());
                }
            }
        }
    }
}
 
void VuoCompiler::Environment::getCacheableModulesAndDependencies(set<string> &cacheableModulesAndDependencies,
                                                                  set<string> &dylibsNeededToLinkToThisCache,
                                                                  set<string> &frameworksNeededToLinkToThisCache)
{
    if (isModuleCacheInitialized && ! isModuleCacheableDataDirty)
    {
        cacheableModulesAndDependencies = moduleCacheContents;
        dylibsNeededToLinkToThisCache = moduleCacheDylibs;
        frameworksNeededToLinkToThisCache = moduleCacheFrameworks;
        return;
    }
 
    VuoCompilerCompatibility compositionTargets = VuoCompilerCompatibility::compatibilityWithTargetTriple(target);
 
    // Include all modules…
    map<string, VuoCompilerModule *> allModules;
    allModules.insert(nodeClasses.begin(), nodeClasses.end());
    allModules.insert(types.begin(), types.end());
    allModules.insert(libraryModules.begin(), libraryModules.end());
 
    set<string> dependencies;
    for (map<string, VuoCompilerModule *>::iterator i = allModules.begin(); i != allModules.end(); ++i)
    {
        string moduleKey = i->first;
        VuoCompilerModule *module = i->second;
 
#if VUO_PRO
        // … except Pro modules and modules that depend on them…
        if (module->requiresPro())
            continue;
#endif
 
        // … and incompatible modules.
        if (! module->getCompatibleTargets().isCompatibleWith(compositionTargets))
            continue;
 
        cacheableModulesAndDependencies.insert(moduleKey);
 
        set<string> moduleDependencies = module->getDependencies();
        dependencies.insert(moduleDependencies.begin(), moduleDependencies.end());
    }
 
    // For the built-in environment, include Vuo's core dependencies.
    if (builtIn && ! generated)
    {
        vector<string> coreDependencies = getCoreVuoDependencies();
        dependencies.insert(coreDependencies.begin(), coreDependencies.end());
    }
 
    // Include all dependencies of the included module that are located in this environment.
    // (All modules are already included, so we only need to handle non-module dependencies.)
    for (set<string>::iterator i = dependencies.begin(); i != dependencies.end(); ++i)
    {
        string dependency = *i;
        if (allModules.find(dependency) == allModules.end())
        {
            if (VuoStringUtilities::endsWith(dependency, ".framework"))
                frameworksNeededToLinkToThisCache.insert(dependency);
            else
            {
                string dependencyPath = VuoCompiler::getLibraryPath(dependency, librarySearchPaths);
                if (! dependencyPath.empty())
                {
                    if (VuoStringUtilities::endsWith(dependencyPath, ".dylib"))
                        dylibsNeededToLinkToThisCache.insert(dependencyPath);
                    else
                        cacheableModulesAndDependencies.insert(dependency);
                }
            }
        }
    }
 
    moduleCacheDylibs = dylibsNeededToLinkToThisCache;
    moduleCacheFrameworks = frameworksNeededToLinkToThisCache;
 
    if (builtIn)
    {
        currentModuleCacheDylib = VuoFileUtilities::buildModuleCacheDylibPath(moduleCachePath, builtIn, generated);
 
        // Give each built-in cache arch a unique name, so they can be built in parallel.
        if (!vuoFrameworkInProgressPath.empty())
            currentModuleCacheDylib += "-" + VuoCompiler::getTargetArch(target);
    }
}
 
void VuoCompiler::Environment::useModuleCache(bool shouldUseExistingCache, VuoCompiler *compiler,
                                              set<string> cacheableModulesAndDependencies,
                                              set<string> dylibsNeededToLinkToCaches, set<string> frameworksNeededToLinkToCaches,
                                              unsigned long lastPrerequisiteModuleCacheRebuild)
{
    // Ignore the cache if the `prelinkCache` preference is false.
 
    static dispatch_once_t checked = 0;
    static bool prelinkCache = true;
    dispatch_once(&checked, ^{
        Boolean valid;
        bool result = CFPreferencesGetAppBooleanValue(CFSTR("prelinkCache"), CFSTR("org.vuo.Editor"), &valid);
        if (valid)
            prelinkCache = result;
    });
    if (! prelinkCache)
    {
        VDebugLog("Ignoring the module cache since the 'prelinkCache' preference is false.");
        return;
    }
 
    // Don't do anything if this environment doesn't have a cache configured.
 
    if (moduleCachePath.empty())
        return;
 
    // Don't bother rechecking the cache if neither the modules in this environment nor the caches that it depends on have changed.
 
    string cacheDescription = VuoFileUtilities::buildModuleCacheDescription(moduleCachePath, generated);
    if (isModuleCacheInitialized && ! isModuleCacheableDataDirty &&
            (builtIn || lastModuleCacheRebuild >= lastPrerequisiteModuleCacheRebuild))
    {
        VDebugLog("No need to recheck %s.", cacheDescription.c_str());
        return;
    }
 
    try
    {
        VDebugLog("Checking if %s is up-to-date…", cacheDescription.c_str());
 
        bool isCacheUpToDate = true;
 
        if (isModuleCacheInitialized && isModuleCacheableDataDirty)
            isCacheUpToDate = false;
 
        isModuleCacheInitialized = true;
        isModuleCacheableDataDirty = false;
 
        string indexPath = VuoFileUtilities::buildModuleCacheIndexPath(moduleCachePath, builtIn, generated);
        if (!vuoFrameworkInProgressPath.empty())
            indexPath += "-" + VuoCompiler::getTargetArch(target);
        string dir, file, ext;
        VuoFileUtilities::splitPath(indexPath, dir, file, ext);
        string indexFileName = file + "." + ext;
 
        // Create the cache directory and index if they don't already exist. (If they do exist, don't affect the last-modified times.)
 
        bool dirExists = VuoFileUtilities::fileExists(moduleCachePath);
        if (! dirExists)
        {
            if (shouldUseExistingCache)
                throw VuoException("Trying to use the existing cache, but the cache directory doesn't exist.", false);
 
            VuoFileUtilities::makeDir(moduleCachePath);
            isCacheUpToDate = false;
        }
 
        bool indexFileExists = VuoFileUtilities::fileExists(indexPath);
        if (! indexFileExists)
        {
            if (shouldUseExistingCache)
                throw VuoException("Trying to use the existing cache, but the cache index doesn't exist.", false);
 
            VuoFileUtilities::createFile(indexPath);
            isCacheUpToDate = false;
        }
 
        // Lock the cache for reading.
 
        VuoFileUtilities::File *fileForLocking;
        {
            fileForLocking = moduleCacheFileForLocking[indexPath];
            if (! fileForLocking)
            {
                fileForLocking = new VuoFileUtilities::File(moduleCachePath, indexFileName);
                moduleCacheFileForLocking[indexPath] = fileForLocking;
            }
 
            if (!fileForLocking->lockForReading())
                VDebugLog("\tWarning: Couldn't lock for reading.");
        }
 
        // If this is the first time this Environment is using its cache, see if there's a dylib on disk.
 
        if (currentModuleCacheDylib.empty())
            currentModuleCacheDylib = VuoFileUtilities::findLatestRevisionOfModuleCacheDylib(moduleCachePath, builtIn, generated, lastModuleCacheRebuild);
 
        if (shouldUseExistingCache && currentModuleCacheDylib.empty())
            throw VuoException("Trying to use the existing cache, but the cache dylib doesn't exist.", false);
 
        // Check if the dylib is newer than the other caches that it depends on.
 
        if (isCacheUpToDate)
            isCacheUpToDate = lastModuleCacheRebuild >= lastPrerequisiteModuleCacheRebuild;
 
        // Check if the dylib looks remotely valid.
 
        if (isCacheUpToDate)
        {
            bool dylibHasData = VuoFileUtilities::fileContainsReadableData(currentModuleCacheDylib);
            if (! dylibHasData)
            {
                if (shouldUseExistingCache)
                    throw VuoException("Trying to use the existing cache, but the cache doesn't contain readable data.", false);
                else
                    isCacheUpToDate = false;
            }
        }
 
        // List the items actually in the cache, according to its index.
 
        const char separator = '\n';
        if (isCacheUpToDate || shouldUseExistingCache)
        {
            VuoFileUtilities::File indexFile(moduleCachePath, indexFileName);
            string index = indexFile.getContentsAsString();
            vector<string> actualIndex = VuoStringUtilities::split(index, separator);
 
            moduleCacheContents.clear();
            moduleCacheContents.insert(actualIndex.begin(), actualIndex.end());
 
            if (shouldUseExistingCache)
            {
                isModuleCacheAvailable = true;
                return;
            }
        }
 
        // Check if the list of actual items matches the list of expected items.
 
        if (isCacheUpToDate)
        {
            if (moduleCacheContents.size() != cacheableModulesAndDependencies.size())
                isCacheUpToDate = false;
            else
            {
                set<string> contentsInBoth;
                std::set_intersection(moduleCacheContents.begin(), moduleCacheContents.end(),
                                      cacheableModulesAndDependencies.begin(), cacheableModulesAndDependencies.end(),
                                      std::inserter(contentsInBoth, contentsInBoth.begin()));
 
                if (contentsInBoth.size() != cacheableModulesAndDependencies.size())
                    isCacheUpToDate = false;
            }
        }
 
        // Check if the cache is newer than all of the modules in it.
 
        if (isCacheUpToDate)
        {
            unsigned long cacheLastModified = VuoFileUtilities::getFileLastModifiedInSeconds(currentModuleCacheDylib);
 
            for (map<string, map<string, ModuleInfo *> >::iterator i = moduleFilesAtSearchPath.begin(); i != moduleFilesAtSearchPath.end(); ++i)
            {
                for (map<string, ModuleInfo *>::iterator j = i->second.begin(); j != i->second.end(); ++j)
                {
                    if (! j->second->isOlderThan(cacheLastModified))
                    {
                        isCacheUpToDate = false;
                        break;
                    }
                }
            }
        }
 
        // If the cache is consistent with this environment, we're done.
 
        if (isCacheUpToDate)
        {
            VDebugLog("Up-to-date.");
 
            isModuleCacheAvailable = true;
            return;
        }
 
        // Otherwise, (re)build the cache.
 
        if (! builtIn)
        {
            currentModuleCacheDylib = VuoFileUtilities::buildModuleCacheDylibPath(moduleCachePath, builtIn, generated);
 
            struct timeval t;
            gettimeofday(&t, NULL);
            lastModuleCacheRebuild = t.tv_sec;
        }
 
        dispatch_async(moduleCacheBuildingQueue, ^{
            VUserLog("Rebuilding %s…", cacheDescription.c_str());
 
            set<Module *> modulesToLink;
            set<string> librariesToLink;
            set<string> frameworksToLink;
            {
                compiler->getLinkerInputs(cacheableModulesAndDependencies, Optimization_SmallBinary, modulesToLink, librariesToLink, frameworksToLink);
 
                librariesToLink.insert(dylibsNeededToLinkToCaches.begin(), dylibsNeededToLinkToCaches.end());
                frameworksToLink.insert(frameworksNeededToLinkToCaches.begin(), frameworksNeededToLinkToCaches.end());
            }
 
            bool gotLockForWriting = false;
            try
            {
                // Try to upgrade the file lock for writing.
                gotLockForWriting = fileForLocking->lockForWriting(true);
                if (! gotLockForWriting)
                    throw VuoException("The cache file is being used by another process. "
                                       "If any composition windows are open from previous Vuo sessions, quit them. "
                                       "If any processes whose names start with \"VuoComposition\" or one of your composition file names appear in Activity Monitor, force-quit them.",
                                       false);
 
                // Link the dependencies to create the cached resources dylib in a temporary file.
                string dir, file, ext;
                VuoFileUtilities::splitPath(currentModuleCacheDylib, dir, file, ext);
                string tmpPath = VuoFileUtilities::makeTmpFile(file, "dylib");
                vector<string> rPaths = compiler->getRunPathSearchPaths(this);
                VuoCompilerIssues *issues = new VuoCompilerIssues;
                compiler->link(tmpPath, modulesToLink, librariesToLink, frameworksToLink, true, rPaths, false, issues);
 
                if (! issues->isEmpty())
                    VUserLog("Warning: May not have fully rebuilt %s for the \"faster build\" optimization:\n%s", cacheDescription.c_str(), issues->getLongDescription(false).c_str());
 
                // Move the temporary file into the cache.
                VuoFileUtilities::moveFile(tmpPath, currentModuleCacheDylib);
 
                // Change the dylib's ID from the temporary path to the path within the cache.
                VuoFileUtilities::executeProcess({
                    getVuoFrameworkPath() + "/Helpers/install_name_tool",
                    "-id",
                    currentModuleCacheDylib,
                    currentModuleCacheDylib,
                });
 
                // Ad-hoc code-sign the runtime-generated System and User caches,
                // but don't ad-hoc code-sign the buildtime-generated Builtin module cache
                // since `framework/CMakeLists.txt` later changes its ID/rpath/loads.
                if (vuoFrameworkInProgressPath.empty())
                    adHocCodeSign(currentModuleCacheDylib);
 
                // Write the list of dependencies to the index file.
                vector<string> expectedContents(cacheableModulesAndDependencies.begin(), cacheableModulesAndDependencies.end());
                string index = VuoStringUtilities::join(expectedContents, separator);
                VuoFileUtilities::writeStringToFile(index, indexPath);
 
                // Delete any older revisions of the dylib.
                VuoFileUtilities::deleteOtherRevisionsOfModuleCacheDylib(currentModuleCacheDylib);
 
                // Downgrade the file lock back to reading.
                if (!fileForLocking->lockForReading())
                    VDebugLog("\tWarning: Couldn't downgrade the lock back to reading.");
 
                dispatch_sync(environmentQueue, ^{
                    moduleCacheContents = cacheableModulesAndDependencies;
                    isModuleCacheAvailable = true;
                });
            }
            catch (VuoException &e)
            {
                // Downgrade the file lock back to reading.
                if (gotLockForWriting)
                    if (!fileForLocking->lockForReading())
                        VDebugLog("\tWarning: Couldn't downgrade the lock back to reading.");
 
                VUserLog("Warning: Couldn't rebuild %s for the \"faster build\" optimization: %s", cacheDescription.c_str(), e.what());
            }
 
            VUserLog("Done.");
        });
    }
    catch (VuoException &e)
    {
        if (vuoFrameworkInProgressPath.empty())
            VUserLog("Warning: Couldn't use %s for the \"faster build\" optimization: %s", cacheDescription.c_str(), e.what());
    }
}
 
void VuoCompiler::Environment::waitForModuleCachesToBuild(void)
{
    dispatch_sync(moduleCacheBuildingQueue, ^{});
}
 
bool VuoCompiler::Environment::findInModuleCache(const string &moduleOrDependency, string &cachePath)
{
    if (isModuleCacheAvailable && moduleCacheContents.find(moduleOrDependency) != moduleCacheContents.end())
    {
        cachePath = currentModuleCacheDylib;
        return true;
    }
 
    return false;
}
 
string VuoCompiler::Environment::getCurrentModuleCacheDylib(void)
{
    return currentModuleCacheDylib;
}
 
unsigned long VuoCompiler::Environment::getLastModuleCacheRebuild(void)
{
    return lastModuleCacheRebuild;
}
 
void VuoCompiler::Environment::modulesChanged(void)
{
    isModuleCacheableDataDirty = true;
    isModuleCacheAvailable = false;
}
 
bool VuoCompiler::Environment::isBuiltInOriginal()
{
    return builtIn && ! generated;
}
 
bool VuoCompiler::Environment::isBuiltIn()
{
    return builtIn;
}
 
bool VuoCompiler::Environment::isGenerated()
{
    return generated;
}
 
string VuoCompiler::Environment::getName()
{
    if (isBuiltInOriginal())
        return "builtin";
    else if (this == sharedEnvironments[target][0][1])
        return "builtin (generated)";
    else if (this == sharedEnvironments[target][1][0])
        return "system";
    else if (this == sharedEnvironments[target][1][1])
        return "system (generated)";
    else if (this == sharedEnvironments[target][2][0])
        return "user";
    else if (this == sharedEnvironments[target][2][1])
        return "user (generated)";
    return "composition-local";
}
 
void VuoCompiler::applyToInstalledEnvironments(void (^doForEnvironment)(Environment *))
{
    dispatch_sync(environmentQueue, ^{
                      for (vector< vector<Environment *> >::iterator i = environments.begin(); i != environments.end(); ++i) {
                          doForEnvironment((*i)[0]);
                      }
                  });
}
 
void VuoCompiler::applyToInstalledEnvironments(void (^doForEnvironment)(Environment *, bool *, string), bool *result, string arg)
{
    dispatch_sync(environmentQueue, ^{
                      for (vector< vector<Environment *> >::iterator i = environments.begin(); i != environments.end(); ++i) {
                          doForEnvironment((*i)[0], result, arg);
                      }
                  });
}
 
void VuoCompiler::applyToAllEnvironments(void (^doForEnvironment)(Environment *environment))
{
    dispatch_sync(environmentQueue, ^{
                      for (vector< vector<Environment *> >::iterator i = environments.begin(); i != environments.end(); ++i) {
                          for (vector<Environment *>::iterator j = i->begin(); j != i->end(); ++j) {
                              doForEnvironment(*j);
                          }
                      }
                  });
}
 
VuoCompiler::VuoCompiler(const string &compositionPath, string target)
{
    if (target.empty())
    {
        this->target = target = getProcessTarget();
        VDebugLog("%p  target=%s (from current process)", this, this->target.c_str());
    }
    else
    {
        this->target = target;
        VDebugLog("%p  target=%s", this, this->target.c_str());
    }
 
#if VUO_PRO
    init_Pro();
#endif
 
    shouldLoadAllModules = true;
    hasLoadedAllModules = false;
    modulesToLoadQueue = dispatch_queue_create("org.vuo.compiler.modules", NULL);
    moduleSourceCompilersExist = dispatch_group_create();
    moduleCacheBuilding = dispatch_group_create();
    dependencyGraph = NULL;
    compositionDependencyGraph = NULL;
    isVerbose = false;
    _shouldShowSplashWindow = false;
    delegate = NULL;
    delegateQueue = dispatch_queue_create("org.vuo.compiler.delegate", NULL);
 
    string vuoFrameworkPath = getVuoFrameworkPath();
    if (! vuoFrameworkPath.empty())
        clangPath = vuoFrameworkPath + "/Helpers/clang";
    else
        clangPath = LLVM_ROOT "/bin/clang";
 
    dispatch_sync(environmentQueue, ^{
                      allCompilers.insert(this);
 
                      if (sharedEnvironments[target].empty())
                      {
                          sharedEnvironments[target] = vector< vector<Environment *> >(3, vector<Environment *>(2, NULL));
                          for (vector< vector<Environment *> >::iterator i = sharedEnvironments[target].begin(); i != sharedEnvironments[target].end(); ++i)
                              for (vector<Environment *>::iterator j = i->begin(); j != i->end(); ++j)
                                  *j = new Environment(this->target, i == sharedEnvironments[target].begin(), j != i->begin());
 
                          vector<string> builtInModuleSearchPaths = Environment::getBuiltInModuleSearchPaths();
                          for (vector<string>::iterator i = builtInModuleSearchPaths.begin(); i != builtInModuleSearchPaths.end(); ++i)
                              sharedEnvironments[target][0][0]->addModuleSearchPath(*i, false);
 
                          vector<string> builtInHeaderSearchPaths = Environment::getBuiltInHeaderSearchPaths();
                          for (vector<string>::iterator i = builtInHeaderSearchPaths.begin(); i != builtInHeaderSearchPaths.end(); ++i)
                              sharedEnvironments[target][0][0]->addHeaderSearchPath(*i);
 
                          vector<string> builtInLibrarySearchPaths = Environment::getBuiltInLibrarySearchPaths();
                          for (vector<string>::iterator i = builtInLibrarySearchPaths.begin(); i != builtInLibrarySearchPaths.end(); ++i)
                              sharedEnvironments[target][0][0]->addLibrarySearchPath(*i);
 
                          vector<string> builtInFrameworkSearchPaths = Environment::getBuiltInFrameworkSearchPaths();
                          for (vector<string>::iterator i = builtInFrameworkSearchPaths.begin(); i != builtInFrameworkSearchPaths.end(); ++i)
                              sharedEnvironments[target][0][0]->addFrameworkSearchPath(*i);
 
                          // Allow system administrator to override Vuo.framework modules
                          sharedEnvironments[target][1][0]->addModuleSearchPath(VuoFileUtilities::getSystemModulesPath());
                          sharedEnvironments[target][1][0]->addLibrarySearchPath(VuoFileUtilities::getSystemModulesPath());
 
                          // Allow user to override Vuo.framework and system-wide modules
                          sharedEnvironments[target][2][0]->addModuleSearchPath(VuoFileUtilities::getUserModulesPath());
                          sharedEnvironments[target][2][0]->addLibrarySearchPath(VuoFileUtilities::getUserModulesPath());
 
                          // Set up module cache paths.
                          // Since the built-in module caches are part of Vuo.framework (put there by `generateBuiltInModuleCaches`),
                          // only attempt to use module caches if Vuo.framework exists.
                          string vuoFrameworkPath = getVuoFrameworkPath();
                          if (! vuoFrameworkPath.empty())
                          {
                              vector<string> moduleCachePaths(3);
                              moduleCachePaths[0] = vuoFrameworkPath + "/Modules/Builtin";
                              moduleCachePaths[1] = VuoFileUtilities::getCachePath() + "/System";
                              moduleCachePaths[2] = VuoFileUtilities::getCachePath() + "/User";
 
                              for (size_t i = 0; i < moduleCachePaths.size(); ++i)
                              {
                                  string moduleCachePath = moduleCachePaths[i];
 
                                  sharedEnvironments[target][i][0]->setModuleCachePath(moduleCachePath, true);
                                  sharedEnvironments[target][i][1]->setModuleCachePath(moduleCachePath, false);
                              }
                          }
                      }
                  });
 
    setCompositionPath(compositionPath);
}
 
VuoCompiler::~VuoCompiler(void)
{
#if VUO_PRO
    fini_Pro();
#endif
 
    dispatch_sync(environmentQueue, ^{
        allCompilers.erase(this);
    });
 
    dispatch_group_wait(moduleCacheBuilding, DISPATCH_TIME_FOREVER);
    dispatch_release(moduleCacheBuilding);
 
    for (vector< vector<Environment *> >::iterator i = environments.begin(); i != environments.end(); ++i)
        (*i)[0]->removeCompilerToNotify(this);
 
    dispatch_sync(delegateQueue, ^{});
 
    dispatch_release(modulesToLoadQueue);
    dispatch_release(delegateQueue);
 
    delete dependencyGraph;
    delete compositionDependencyGraph;
}
 
void VuoCompiler::reset(void)
{
    dispatch_group_wait(moduleSourceCompilersExistGlobally, DISPATCH_TIME_FOREVER);
 
    dispatch_sync(environmentQueue, ^{
 
    for (auto e : sharedEnvironments)
        for (vector< vector<Environment *> >::iterator i = e.second.begin(); i != e.second.end(); ++i)
        {
            (*i)[0]->stopWatchingModuleSearchPaths();
            dispatch_sync((*i)[0]->moduleSearchPathContentsChangedQueue, ^{});
        }
 
    for (auto e : environmentsForCompositionFamily)
        for (map< string, vector<Environment *> >::iterator i = e.second.begin(); i != e.second.end(); ++i)
        {
            (i->second)[0]->stopWatchingModuleSearchPaths();
            dispatch_sync((i->second)[0]->moduleSearchPathContentsChangedQueue, ^{});
        }
 
    for (auto e : sharedEnvironments)
        for (vector< vector<Environment *> >::iterator i = e.second.begin(); i != e.second.end(); ++i)
            for (vector<Environment *>::iterator j = i->begin(); j != i->end(); ++j)
                delete *j;
 
    for (auto e : environmentsForCompositionFamily)
        for (map< string, vector<Environment *> >::iterator i = e.second.begin(); i != e.second.end(); ++i)
            for (vector<Environment *>::iterator j = i->second.begin(); j != i->second.end(); ++j)
                delete *j;
 
    allCompilers.clear();
    sharedEnvironments.clear();
    environmentsForCompositionFamily.clear();
 
    });
}
 
void VuoCompiler::setDelegate(VuoCompilerDelegate *delegate)
{
    dispatch_async(delegateQueue, ^{
                       this->delegate = delegate;
                   });
}
 
void VuoCompiler::setCompositionPath(const string &compositionPath)
{
    string compositionModulesDir;
    string compositionBaseDir;
    lastCompositionIsSubcomposition = false;
    if (! compositionPath.empty())
    {
        compositionModulesDir = VuoFileUtilities::getCompositionLocalModulesPath(compositionPath);
 
        string file, ext;
        VuoFileUtilities::splitPath(compositionModulesDir, compositionBaseDir, file, ext);
        VuoFileUtilities::canonicalizePath(compositionBaseDir);
 
        string compositionDir;
        VuoFileUtilities::splitPath(compositionPath, compositionDir, file, ext);
        VuoFileUtilities::canonicalizePath(compositionDir);
        lastCompositionIsSubcomposition = (compositionDir == compositionModulesDir);
    }
 
    // Set up `environments` to contain all environments available to this compiler, in order from broadest to narrowest.
 
    dispatch_sync(environmentQueue, ^{
                      if (! environments.empty() && compositionBaseDir == lastCompositionBaseDir) {
                          return;
                      }
                      lastCompositionBaseDir = compositionBaseDir;
 
                      // Clear out the existing environments for this compiler.
 
                      Environment *oldCompositionFamilyInstalledEnvironment = nullptr;
                      vector<Environment *> compositionEnvironments;
                      if (! environments.empty())
                      {
                          for (vector< vector<Environment *> >::iterator i = environments.begin(); i != environments.end(); ++i) {
                              (*i)[0]->removeCompilerToNotify(this);
                          }
 
                          if (environments.size() >= 5) {
                              oldCompositionFamilyInstalledEnvironment = environments[3][0];
                          }
 
                          compositionEnvironments = environments.back();
 
                          environments.clear();
                      }
 
                      // If the composition is located in one of the shared environments (built-in, system, user),
                      // add that shared environment and any shared environments at broader scope to the compiler.
                      // If the composition is not in a shared environment, add all of the shared environments to the compiler.
 
                      bool isCompositionInSharedEnvironment = false;
                      for (vector< vector<Environment *> >::iterator i = sharedEnvironments[target].begin(); i != sharedEnvironments[target].end(); ++i)
                      {
                          environments.push_back(*i);
 
                          vector<string> moduleSearchPaths = (*i)[0]->getModuleSearchPaths();
                          for (vector<string>::iterator j = moduleSearchPaths.begin(); j != moduleSearchPaths.end(); ++j)
                          {
                              string moduleSearchPath = *j;
                              VuoFileUtilities::canonicalizePath(moduleSearchPath);
                              if (moduleSearchPath == compositionModulesDir)
                              {
                                  isCompositionInSharedEnvironment = true;
                                  break;
                              }
                          }
 
                          if (isCompositionInSharedEnvironment) {
                              break;
                          }
                      }
 
                      // If the composition is not in a shared environment, add the composition-family environment to the compiler.
 
                      Environment *newCompositionFamilyInstalledEnvironment = nullptr;
                      if (! isCompositionInSharedEnvironment && ! compositionPath.empty())
                      {
                          vector<Environment *> compositionFamilyEnvironments = environmentsForCompositionFamily[target][compositionBaseDir];
                          if (compositionFamilyEnvironments.empty())
                          {
                              compositionFamilyEnvironments = vector<Environment *>(2, NULL);
                              compositionFamilyEnvironments[0] = new Environment(this->target, false, false);
                              compositionFamilyEnvironments[1] = new Environment(this->target, false, true);
                              environmentsForCompositionFamily[target][compositionBaseDir] = compositionFamilyEnvironments;
 
                              // Allow the user to place modules/subcompositions in a Modules folder inside the composition folder.
 
                              compositionFamilyEnvironments[0]->addModuleSearchPath(compositionModulesDir);
 
                              // Locate this environment's cache in a folder whose name is the composition folder path with
                              // slashes replaced with Unicode Modifier Letter Colon.
                              string moduleCachePath = getCachePathForComposition(compositionBaseDir);
 
                              compositionFamilyEnvironments[0]->setModuleCachePath(moduleCachePath, true);
                              compositionFamilyEnvironments[1]->setModuleCachePath(moduleCachePath, false);
                          }
                          environments.push_back(compositionFamilyEnvironments);
 
                          newCompositionFamilyInstalledEnvironment = compositionFamilyEnvironments[0];
                      }
 
                      // Add the composition environment to the compiler (or add it back in if it already existed).
 
                      if (compositionEnvironments.empty())
                      {
                          compositionEnvironments = vector<Environment *>(2, NULL);
                          compositionEnvironments[0] = new Environment(this->target, false, false);
                          compositionEnvironments[1] = new Environment(this->target, false, true);
                      }
                      environments.push_back(compositionEnvironments);
 
                      for (vector< vector<Environment *> >::iterator i = environments.begin(); i != environments.end(); ++i) {
                          (*i)[0]->addCompilerToNotify(this);
                      }
 
                      delete dependencyGraph;
                      delete compositionDependencyGraph;
                      dependencyGraph = makeDependencyNetwork(environments, ^VuoDirectedAcyclicGraph * (Environment *env) { return env->getDependencyGraph(); });
                      compositionDependencyGraph = makeDependencyNetwork(environments, ^VuoDirectedAcyclicGraph * (Environment *env) { return env->getCompositionDependencyGraph(); });
 
                      // If the compiler has a different local Modules directory than before, notify the compiler's delegate
                      // of composition-family modules that are newly available/unavailable.
 
                      if (oldCompositionFamilyInstalledEnvironment != newCompositionFamilyInstalledEnvironment)
                      {
                          auto getModules = [] (Environment *env)
                          {
                              map<string, VuoCompilerModule *> modules;
                              if (env)
                              {
                                  for (auto i : env->getNodeClasses()) {
                                      modules.insert(i);
                                  }
                                  for (auto i : env->getTypes()) {
                                      modules.insert(i);
                                  }
                                  for (auto i : env->getLibraryModules()) {
                                      modules.insert(i);
                                  }
                              }
                              return modules;
                          };
 
                          map<string, VuoCompilerModule *> modulesAdded = getModules(newCompositionFamilyInstalledEnvironment);
                          map<string, VuoCompilerModule *> modulesRemoved = getModules(oldCompositionFamilyInstalledEnvironment);
 
                          map<string, pair<VuoCompilerModule *, VuoCompilerModule *> > modulesModified;
                          for (map<string, VuoCompilerModule *>::iterator add = modulesAdded.begin(); add != modulesAdded.end(); )
                          {
                              map<string, VuoCompilerModule *>::iterator rem = modulesRemoved.find(add->first);
                              if (rem != modulesRemoved.end())
                              {
                                  modulesModified[add->first] = make_pair(rem->second, add->second);
                                  modulesAdded.erase(add++);
                                  modulesRemoved.erase(rem);
                              }
                              else
                              {
                                  ++add;
                              }
                          }
 
                          if (! (modulesAdded.empty() && modulesModified.empty() && modulesRemoved.empty()) )
                          {
                              VuoCompilerIssues *issues = new VuoCompilerIssues();
                              VuoCompilerDelegate::LoadedModulesData *delegateData = new VuoCompilerDelegate::LoadedModulesData(set< pair<VuoCompilerModule *, VuoCompilerModule *> >(), set<VuoCompilerModule *>(), issues);
                              delegateData->retain();
 
                              Environment *scopeEnvironment = newCompositionFamilyInstalledEnvironment;
                              if (! scopeEnvironment) {
                                  scopeEnvironment = compositionEnvironments.at(0);
                              }
 
                              loadedModules(modulesAdded, modulesModified, modulesRemoved, issues, delegateData, scopeEnvironment);
                          }
                      }
                  });
}
 
VuoDirectedAcyclicNetwork * VuoCompiler::makeDependencyNetwork(const vector< vector<Environment *> > &environments,
                                                               VuoDirectedAcyclicGraph * (^graphForEnvironment)(Environment *))
{
    if (!graphForEnvironment)
        return NULL;
 
    VuoDirectedAcyclicNetwork *network = new VuoDirectedAcyclicNetwork();
 
    for (vector< vector<Environment *> >::const_iterator i = environments.begin(); i != environments.end(); ++i)
    {
        // Installed environment depends on generated environment in same scope.
 
        network->addEdge(graphForEnvironment(i->at(0)), graphForEnvironment(i->at(1)));
 
        // Installed and generated environments depend on installed environments in broader scopes.
 
        for (vector< vector<Environment *> >::const_iterator ii = environments.begin(); ii != i; ++ii)
        {
            network->addEdge(graphForEnvironment(i->at(0)), graphForEnvironment(ii->at(0)));
            network->addEdge(graphForEnvironment(i->at(1)), graphForEnvironment(ii->at(0)));
        }
    }
 
    return network;
}
 
void VuoCompiler::loadModulesIfNeeded(const set<string> &moduleKeys)
{
    __block bool willLoadAllModules = false;
    if (moduleKeys.empty())
    {
        dispatch_sync(modulesToLoadQueue, ^{
                          if (shouldLoadAllModules && ! hasLoadedAllModules) {
                              willLoadAllModules = true;
                              hasLoadedAllModules = true;
                          }
                      });
    }
 
    if (! willLoadAllModules && moduleKeys.empty())
        return;
 
    // Load modules and start sources compiling.
 
    dispatch_group_enter(moduleSourceCompilersExist);
    __block set<dispatch_group_t> sourcesLoading;
    dispatch_sync(environmentQueue, ^{
                      sourcesLoading = loadModulesAndSources(moduleKeys, set<string>(), set<string>(),
                                                             moduleKeys, set<string>(), set<string>(),
                                                             willLoadAllModules, false, nullptr, nullptr, nullptr, "");
                  });
 
    // Wait for subcompositions and specialized node classes to finish compiling and their modules to be loaded
    // to ensure that the next call to getNodeClass() will return them.
 
    for (set<dispatch_group_t>::iterator i = sourcesLoading.begin(); i != sourcesLoading.end(); ++i)
    {
        dispatch_group_wait(*i, DISPATCH_TIME_FOREVER);
        dispatch_release(*i);
    }
    dispatch_group_leave(moduleSourceCompilersExist);
}
 
set<dispatch_group_t> VuoCompiler::loadModulesAndSources(const set<string> &modulesAddedKeys, const set<string> &modulesModifiedKeys, const set<string> &modulesRemovedKeys,
                                                         const set<string> &sourcesAddedKeys, const set<string> &sourcesModifiedKeys, const set<string> &sourcesRemovedKeys,
                                                         bool willLoadAllModules, bool shouldRecompileSourcesIfUnchanged,
                                                         Environment *currentEnvironment, VuoCompilerIssues *issuesForCurrentEnvironment,
                                                         std::function<void(void)> moduleLoadedCallback, const string &moduleAddedOrModifiedSourceCode)
{
    //VLog("C=%p E=%p -- %lu %lu %lu  %lu %lu %lu  %i %i", this, currentEnvironment,
         //modulesAddedKeys.size(), modulesModifiedKeys.size(), modulesRemovedKeys.size(),
         //sourcesAddedKeys.size(), sourcesModifiedKeys.size(), sourcesRemovedKeys.size(),
         //willLoadAllModules, shouldRecompileSourcesIfUnchanged);
    //if (modulesAddedKeys.size() == 1) VLog("    %s", modulesAddedKeys.begin()->c_str());
    //if (modulesModifiedKeys.size() == 1) VLog("    %s", modulesModifiedKeys.begin()->c_str());
    //if (modulesRemovedKeys.size() == 1) VLog("    %s", modulesRemovedKeys.begin()->c_str());
 
    // Organize the modules, source files, and issues by environment.
 
    map<Environment *, set<string> > modulesAdded;
    map<Environment *, set<string> > modulesModified;
    map<Environment *, set<string> > modulesRemoved;
    map<Environment *, set<string> > sourcesAdded;
    map<Environment *, set<string> > sourcesModified;
    map<Environment *, set<string> > sourcesRemoved;
    map<Environment *, set<string> > potentialSpecializedModules;
 
    if (currentEnvironment)
    {
        modulesAdded[currentEnvironment] = modulesAddedKeys;
        modulesModified[currentEnvironment] = modulesModifiedKeys;
        modulesRemoved[currentEnvironment] = modulesRemovedKeys;
        sourcesAdded[currentEnvironment] = sourcesAddedKeys;
        sourcesModified[currentEnvironment] = sourcesModifiedKeys;
        sourcesRemoved[currentEnvironment] = sourcesRemovedKeys;
    }
    else
    {
        Environment *genEnv = nullptr;
        if (! willLoadAllModules)
        {
            // If compiling a top-level composition, generated modules that were directly requested (in modulesAddedKeys) are
            // added at the composition scope so they won't be cached. This prevents link errors when running multiple
            // compositions in the current process (https://b33p.net/kosada/node/14317).
 
            int scope = environments.size() - (lastCompositionIsSubcomposition ? 2 : 1);
            genEnv = environments.at(scope).at(1);
            potentialSpecializedModules[genEnv] = modulesAddedKeys;
        }
 
        for (vector< vector<Environment *> >::iterator i = environments.begin(); i != environments.end(); ++i)
        {
            Environment *env = (*i).at(0);
 
            ModuleInfoIterator modulesAddedIter = (willLoadAllModules ? env->listAllModules() : env->listModules(modulesAddedKeys));
            ModuleInfoIterator sourcesAddedIter = (willLoadAllModules ? env->listAllSourceFiles() : env->listSourceFiles(sourcesAddedKeys));
            ModuleInfoIterator sourcesModifiedIter = (willLoadAllModules ? env->listAllSourceFiles() : env->listSourceFiles(sourcesModifiedKeys));
 
            ModuleInfo *moduleInfo;
            while ((moduleInfo = modulesAddedIter.next()))
            {
                string moduleKey = moduleInfo->getModuleKey();
 
                modulesAdded[env].insert(moduleKey);
 
                if (! willLoadAllModules)
                {
                    auto foundIter = potentialSpecializedModules[genEnv].find(moduleKey);
                    if (foundIter != potentialSpecializedModules[genEnv].end())
                        potentialSpecializedModules[genEnv].erase(foundIter);
                }
            }
 
            // If a source file and a compiled file for the same module are in the same folder,
            // the compiled file takes precedence.
            auto isCompiledModuleAtSameSearchPath = [&env] (ModuleInfo *sourceInfo)
            {
                ModuleInfo *compiledModuleInfo = env->listModule(sourceInfo->getModuleKey());
                return (compiledModuleInfo && compiledModuleInfo->getSearchPath() == sourceInfo->getSearchPath());
            };
 
            while ((moduleInfo = sourcesAddedIter.next()))
            {
                if (isCompiledModuleAtSameSearchPath(moduleInfo))
                    continue;
 
                sourcesAdded[env].insert( moduleInfo->getModuleKey() );
            }
 
            while ((moduleInfo = sourcesModifiedIter.next()))
            {
                if (isCompiledModuleAtSameSearchPath(moduleInfo))
                    continue;
 
                sourcesModified[env].insert( moduleInfo->getModuleKey() );
            }
        }
    }
 
    map<Environment *, VuoCompilerIssues *> issues;
    for (vector< vector<Environment *> >::iterator i = environments.begin(); i != environments.end(); ++i)
    {
        Environment *env = (*i).at(0);
        issues[env] = (env == currentEnvironment && issuesForCurrentEnvironment ? issuesForCurrentEnvironment : new VuoCompilerIssues());
    }
 
    // Check for circular dependencies in added/modified sources.
 
    for (vector< vector<Environment *> >::iterator i = environments.begin(); i != environments.end(); ++i)
    {
        Environment *env = (*i).at(0);
 
        // Check for circular dependencies involving sources being loaded within this environment.
        // For circular dependencies involving sources in different environments,
        // an error will be reported elsewhere due to one of them being outside of the other's scope.
        set<VuoDirectedAcyclicGraph::Vertex *> circularDependencies = env->getCompositionDependencyGraph()->getCycleVertices();
 
        set<string> sourcesAddedModified;
        sourcesAddedModified.insert(sourcesAdded[env].begin(), sourcesAdded[env].end());
        sourcesAddedModified.insert(sourcesModified[env].begin(), sourcesModified[env].end());
 
        for (set<string>::iterator j = sourcesAddedModified.begin(); j != sourcesAddedModified.end(); ++j)
        {
            string moduleKey = *j;
 
            bool found = false;
            for (set<VuoDirectedAcyclicGraph::Vertex *>::iterator k = circularDependencies.begin(); k != circularDependencies.end(); ++k)
            {
                DependencyGraphVertex *vertex = static_cast<DependencyGraphVertex *>(*k);
                if (vertex->getDependency() == moduleKey)
                {
                    found = true;
                    break;
                }
            }
 
            if (found)
            {
                sourcesAdded[env].erase(moduleKey);
                sourcesModified[env].erase(moduleKey);
 
                VuoCompilerIssue issue(VuoCompilerIssue::Error, "compiling subcomposition", moduleKey,
                                       "Subcomposition contains itself",
                                       "%moduleKey contains an instance of itself, "
                                       "or contains another subcomposition that contains an instance of %moduleKey.");
                issue.setModuleKey(moduleKey);
 
                ModuleInfo *sourceInfo = env->listSourceFile(moduleKey);
                if (sourceInfo)
                    issue.setFilePath(sourceInfo->getFile()->path());
 
                issues[env]->append(issue);
            }
        }
    }
 
    // Update the longest downstream paths for added/modified sources.
 
    for (const vector<Environment *> &envs : environments)
    {
        Environment *env = envs.at(0);
 
        set<string> sourcesAddedModified;
        sourcesAddedModified.insert(sourcesAdded[env].begin(), sourcesAdded[env].end());
        sourcesAddedModified.insert(sourcesModified[env].begin(), sourcesModified[env].end());
 
        for (const string &moduleKey : sourcesAddedModified)
        {
            VuoDirectedAcyclicGraph::Vertex *vertex = env->getCompositionDependencyGraph()->findVertex(moduleKey);
            int pathLength = env->getCompositionDependencyGraph()->getLongestDownstreamPath(vertex);
 
            ModuleInfo *sourceInfo = env->listSourceFile(moduleKey);
            sourceInfo->setLongestDownstreamPath(pathLength);
        }
    }
 
    // Find all modules and sources that depend on the modules and sources being modified or removed.
    // Those that belong to one of this compiler's environments are used in subsequent stages.
    // Those that belong to some other environment are scheduled to be handled by a separate call to this function.
 
    map<Environment *, set<string> > modulesDepOnModulesModified;
    map<Environment *, set<string> > sourcesDepOnModulesModified;
    map<Environment *, set<string> > modulesDepOnModulesRemoved;
    map<Environment *, set<string> > sourcesDepOnModulesRemoved;
 
    {
        __block map<Environment *, set<string> > modulesDepOnModulesModified_otherCompiler;
        __block map<Environment *, set<string> > sourcesDepOnModulesModified_otherCompiler;
        __block map<Environment *, set<string> > modulesDepOnModulesRemoved_otherCompiler;
        __block map<Environment *, set<string> > sourcesDepOnModulesRemoved_otherCompiler;
 
        vector<VuoDirectedAcyclicNetwork *> searchDependencyGraphs;
        for (VuoCompiler *compiler : allCompilers)
            searchDependencyGraphs.push_back(compiler->dependencyGraph);
 
        VuoDirectedAcyclicGraph *currentEnvironmentDependencyGraph = (currentEnvironment ? currentEnvironment->getDependencyGraph() : nullptr);
 
        findDependentModulesAndSources(modulesModified, searchDependencyGraphs, currentEnvironmentDependencyGraph,
                                       modulesDepOnModulesModified, modulesDepOnModulesModified_otherCompiler,
                                       sourcesDepOnModulesModified, sourcesDepOnModulesModified_otherCompiler);
 
        findDependentModulesAndSources(modulesRemoved, searchDependencyGraphs, currentEnvironmentDependencyGraph,
                                       modulesDepOnModulesRemoved, modulesDepOnModulesRemoved_otherCompiler,
                                       sourcesDepOnModulesRemoved, sourcesDepOnModulesRemoved_otherCompiler);
 
        set<Environment *> otherEnvironments;
        for (map<Environment *, set<string> >::iterator i = modulesDepOnModulesModified_otherCompiler.begin(); i != modulesDepOnModulesModified_otherCompiler.end(); ++i)
            otherEnvironments.insert(i->first);
        for (map<Environment *, set<string> >::iterator i = sourcesDepOnModulesModified_otherCompiler.begin(); i != sourcesDepOnModulesModified_otherCompiler.end(); ++i)
            otherEnvironments.insert(i->first);
        for (map<Environment *, set<string> >::iterator i = modulesDepOnModulesRemoved_otherCompiler.begin(); i != modulesDepOnModulesRemoved_otherCompiler.end(); ++i)
            otherEnvironments.insert(i->first);
        for (map<Environment *, set<string> >::iterator i = sourcesDepOnModulesRemoved_otherCompiler.begin(); i != sourcesDepOnModulesRemoved_otherCompiler.end(); ++i)
            otherEnvironments.insert(i->first);
 
        for (Environment *env : otherEnvironments)
        {
            VuoCompiler *otherCompiler = nullptr;
            for (VuoCompiler *c : allCompilers)
                for (const vector<Environment *> &ee : c->environments)
                    for (Environment *e : ee)
                        if (e == env)
                        {
                            otherCompiler = c;
                            goto foundOtherCompiler;
                        }
            foundOtherCompiler:
 
            dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
                dispatch_sync(environmentQueue, ^{
                    otherCompiler->loadModulesAndSources(set<string>(), modulesDepOnModulesModified_otherCompiler[env], modulesDepOnModulesRemoved_otherCompiler[env],
                                                         set<string>(), sourcesDepOnModulesModified_otherCompiler[env], sourcesDepOnModulesRemoved_otherCompiler[env],
                                                         false, true, env, nullptr, nullptr, "");
                });
            });
        }
    }
 
    // Unload:
    //   - modules that have been removed or modified
    //   - modules that depend on them
 
    map<Environment *, set<VuoCompilerModule *> > actualModulesRemoved;
    for (const vector<Environment *> &envs : environments)
    {
        for (Environment *env : envs)
        {
            set<string> modulesToUnload;
            modulesToUnload.insert(modulesRemoved[env].begin(), modulesRemoved[env].end());
            modulesToUnload.insert(modulesModified[env].begin(), modulesModified[env].end());
            modulesToUnload.insert(modulesDepOnModulesRemoved[env].begin(), modulesDepOnModulesRemoved[env].end());
            modulesToUnload.insert(modulesDepOnModulesModified[env].begin(), modulesDepOnModulesModified[env].end());
 
            actualModulesRemoved[env] = env->unloadCompiledModules(modulesToUnload);
 
            if (!env->isBuiltInOriginal() && !actualModulesRemoved[env].empty())
            {
                set<string> actualModulesRemovedKeys;
                for (auto m : actualModulesRemoved[env])
                    actualModulesRemovedKeys.insert(m->getPseudoBase()->getModuleKey());
                VUserLog("Removed from %s environment: %s", env->getName().c_str(), VuoStringUtilities::join(actualModulesRemovedKeys, ", ").c_str());
            }
        }
    }
 
    // Load:
    //   - modules that have been added or modified
    //   - modules that they depend on
    //   - modules that depend on them that were just unloaded
    // Delete:
    //   - cached module files in `modulesToLoad` whose source files have been removed
 
    map<Environment *, set<string> > modulesToLoad;
    map<Environment *, map<string, string> > modulesToLoadSourceCode;
    for (vector< vector<Environment *> >::iterator i = environments.begin(); i != environments.end(); ++i)
    {
        Environment *env = (*i).at(0);
 
        if (! modulesAdded[env].empty())
            modulesToLoad[env].insert(modulesAdded[env].begin(), modulesAdded[env].end());
        if (! modulesModified[env].empty())
            modulesToLoad[env].insert(modulesModified[env].begin(), modulesModified[env].end());
        if (! modulesDepOnModulesModified[env].empty())
            modulesToLoad[env].insert(modulesDepOnModulesModified[env].begin(), modulesDepOnModulesModified[env].end());
 
        if (env == currentEnvironment && moduleLoadedCallback)
        {
            if (modulesAdded[env].size() == 1)
                modulesToLoadSourceCode[env][*modulesAdded[env].begin()] = moduleAddedOrModifiedSourceCode;
            else if (modulesModified[env].size() == 1)
                modulesToLoadSourceCode[env][*modulesModified[env].begin()] = moduleAddedOrModifiedSourceCode;
        }
    }
 
    map<Environment *, set<VuoCompilerModule *> > actualModulesAdded;
    while (! modulesToLoad.empty())
    {
        set<string> dependenciesToLoad;
        map<Environment *, set<string> > potentialSpecializedDependencies;
        for (vector< vector<Environment *> >::iterator i = environments.begin(); i != environments.end(); ++i)
        {
            Environment *env = (*i).at(0);
            Environment *genEnv = (*i).at(1);
 
            set<VuoCompilerModule *> actualModulesLoaded = env->loadCompiledModules(modulesToLoad[env], modulesToLoadSourceCode[env]);
 
            actualModulesAdded[env].insert(actualModulesLoaded.begin(), actualModulesLoaded.end());
            modulesToLoad.erase(env);
 
            for (set<VuoCompilerModule *>::iterator j = actualModulesLoaded.begin(); j != actualModulesLoaded.end(); ++j)
            {
                set<string> dependencies = (*j)->getDependencies();
                dependenciesToLoad.insert(dependencies.begin(), dependencies.end());
                potentialSpecializedDependencies[genEnv].insert(dependencies.begin(), dependencies.end());
            }
 
            if (!env->isBuiltInOriginal() && !actualModulesLoaded.empty())
            {
                map<string, string> actualFilesAndHashesLoaded;
                for (auto module : actualModulesLoaded)
                {
                    string path, hash;
                    if (module->getPseudoBase()->getNodeSet())
                        path = module->getPseudoBase()->getNodeSet()->getArchivePath();
                    else
                    {
                        auto cnc = dynamic_cast<VuoCompilerNodeClass *>(module);
                        if (cnc && !cnc->getSourcePath().empty())
                        {
                            path = cnc->getSourcePath();
                            if (!cnc->getSourceCode().empty())
                                // Use the latest source code, if it's been modified without saving.
                                hash = VuoStringUtilities::calculateSHA256(cnc->getSourceCode());
                        }
                        else
                            path = module->getModulePath();
                    }
 
                    if (hash.empty())
                        try
                        {
                            hash = VuoFileUtilities::calculateFileSHA256(path);
                        }
                        catch (VuoException &e) {}
 
                    actualFilesAndHashesLoaded[path] = hash;
                }
 
                for (pair<string, string> item : actualFilesAndHashesLoaded)
                    VUserLog("Loaded into %s environment:  [%8.8s] %s", env->getName().c_str(), item.second.c_str(), item.first.c_str());
            }
        }
 
        for (vector< vector<Environment *> >::iterator i = environments.begin(); i != environments.end(); ++i)
        {
            Environment *env = (*i).at(0);
 
            ModuleInfoIterator dependenciesInEnv = env->listModules(dependenciesToLoad);
            ModuleInfo *moduleInfo;
            while ((moduleInfo = dependenciesInEnv.next()))
            {
                modulesToLoad[env].insert( moduleInfo->getModuleKey() );
 
                for (map<Environment *, set<string> >::iterator j = potentialSpecializedDependencies.begin(); j != potentialSpecializedDependencies.end(); ++j)
                {
                    auto foundIter = j->second.find( moduleInfo->getModuleKey() );
                    if (foundIter != j->second.end())
                        j->second.erase(foundIter);
                }
            }
        }
 
        for (vector< vector<Environment *> >::iterator i = environments.begin(); i != environments.end(); ++i)
        {
            Environment *genEnv = (*i).at(1);
            potentialSpecializedModules[genEnv].insert(potentialSpecializedDependencies[genEnv].begin(), potentialSpecializedDependencies[genEnv].end());
        }
    }
 
    // Load asynchronously:
    //   - specializations of generic modules
 
    set<dispatch_group_t> specializedModulesLoading;
    for (vector< vector<Environment *> >::iterator i = environments.begin(); i != environments.end(); ++i)
    {
        Environment *genEnv = (*i).at(1);
        set<dispatch_group_t> s = genEnv->loadSpecializedModules(potentialSpecializedModules[genEnv], this, llvmQueue);
        specializedModulesLoading.insert(s.begin(), s.end());
    }
 
    // Notify those waiting on a source file to be compiled that its module has now been loaded.
 
    if (moduleLoadedCallback)
        moduleLoadedCallback();
 
    // Move modified modules from `actualModulesAdded` and `actualModulesRemoved` to `actualModulesModified`.
 
    map<Environment *, set< pair<VuoCompilerModule *, VuoCompilerModule *> > > actualModulesModified;
    for (vector< vector<Environment *> >::iterator i = environments.begin(); i != environments.end(); ++i)
    {
        Environment *env = (*i).at(0);
 
        for (set<VuoCompilerModule *>::iterator add = actualModulesAdded[env].begin(); add != actualModulesAdded[env].end(); )
        {
            set<VuoCompilerModule *>::iterator rem;
            for (rem = actualModulesRemoved[env].begin(); rem != actualModulesRemoved[env].end(); ++rem)
                if ((*rem)->getPseudoBase()->getModuleKey() == (*add)->getPseudoBase()->getModuleKey())
                    break;
 
            if (rem != actualModulesRemoved[env].end())
            {
                actualModulesModified[env].insert( make_pair(*rem, *add) );
                actualModulesRemoved[env].erase(rem);
                actualModulesAdded[env].erase(add++);
            }
            else
                ++add;
        }
    }
 
    // Reify port types on node classes (if needed).
 
    bool wereModulesAddedOrModified = false;
    for (vector< vector<Environment *> >::iterator i = environments.begin(); i != environments.end(); ++i)
    {
        Environment *env = (*i).at(0);
        if (! (actualModulesAdded[env].empty() && actualModulesModified[env].empty()) )
        {
            wereModulesAddedOrModified = true;
            break;
        }
    }
 
    if (wereModulesAddedOrModified)
    {
        map<string, VuoCompilerType *> inheritedTypes;
        for (const vector<Environment *> &envs : environments)
        {
            for (Environment *env : envs)
            {
                env->reifyPortTypes(inheritedTypes);
                map<string, VuoCompilerType *> envTypes = env->getTypes();
                inheritedTypes.insert(envTypes.begin(), envTypes.end());
            }
        }
    }
 
    // Delete cached compiled module files and call this function recursively for:
    //   - modules whose source files have been removed
    //   - modules whose source files depend on them
 
    for (vector< vector<Environment *> >::iterator i = environments.begin(); i != environments.end(); ++i)
    {
        Environment *env = (*i).at(0);
 
        set<string> sourcesToUnload;
        sourcesToUnload.insert(sourcesRemoved[env].begin(), sourcesRemoved[env].end());
        sourcesToUnload.insert(sourcesDepOnModulesRemoved[env].begin(), sourcesDepOnModulesRemoved[env].end());
        if (! sourcesToUnload.empty())
        {
            string moduleSearchPath = env->getModuleSearchPaths().front();
 
            dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
                VuoCompiler *otherCompiler = new VuoCompiler(moduleSearchPath + "/unused", target);
 
                dispatch_sync(environmentQueue, ^{
                    otherCompiler->loadModulesAndSources(set<string>(), set<string>(), sourcesToUnload,
                                                         set<string>(), set<string>(), set<string>(),
                                                         false, false, env, nullptr, nullptr, "");
                });
 
                delete otherCompiler;
            });
        }
 
        if (!env->isBuiltInOriginal() && !sourcesToUnload.empty())
            VUserLog("Deleting from %s environment: %s", env->getName().c_str(), VuoStringUtilities::join(sourcesToUnload, ", ").c_str());
 
        env->deleteModulesCompiledFromSourceCode(sourcesToUnload);
    }
 
    // Compile asynchronously:
    //   - source files that have been added or modified
    //   - source files that depend on them
    //   - source files that depend on modules that have been modified
 
    map<Environment *, set<string> > sourcesDepOnModulesAdded;
    {
        map<Environment *, set<string> > modulesDepOnModulesAdded;                        // unused
        __block map<Environment *, set<string> > modulesDepOnModulesAdded_otherCompiler;  //
        __block map<Environment *, set<string> > sourcesDepOnModulesAdded_otherCompiler;
 
        map<Environment *, set<string> > actualModuleKeysAdded;
        for (const vector<Environment *> &envs : environments)
        {
            Environment *env = envs.at(0);
            for (VuoCompilerModule *module : actualModulesAdded[env])
                actualModuleKeysAdded[env].insert( module->getPseudoBase()->getModuleKey() );
        }
 
        vector<VuoDirectedAcyclicNetwork *> searchDependencyGraphs;
        searchDependencyGraphs.push_back(compositionDependencyGraph);
        for (map<string, vector<Environment *> >::iterator ii = environmentsForCompositionFamily[target].begin(); ii != environmentsForCompositionFamily[target].end(); ++ii)
        {
            vector< vector<Environment *> > otherEnvs = sharedEnvironments[target];
            otherEnvs.push_back(ii->second);
            VuoDirectedAcyclicNetwork *other = makeDependencyNetwork(otherEnvs, ^VuoDirectedAcyclicGraph * (Environment *env) { return env->getCompositionDependencyGraph(); });
            searchDependencyGraphs.push_back(other);
        }
 
        VuoDirectedAcyclicGraph *currentEnvironmentDependencyGraph = (currentEnvironment ? currentEnvironment->getCompositionDependencyGraph() : nullptr);
 
        findDependentModulesAndSources(actualModuleKeysAdded, searchDependencyGraphs, currentEnvironmentDependencyGraph,
                                       modulesDepOnModulesAdded, modulesDepOnModulesAdded_otherCompiler,
                                       sourcesDepOnModulesAdded, sourcesDepOnModulesAdded_otherCompiler);
 
        set<Environment *> otherEnvironments;
        for (map<Environment *, set<string> >::iterator i = sourcesDepOnModulesAdded_otherCompiler.begin(); i != sourcesDepOnModulesAdded_otherCompiler.end(); ++i)
            otherEnvironments.insert(i->first);
 
        for (Environment *env : otherEnvironments)
        {
            dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
                string moduleSearchPath = env->getModuleSearchPaths().front();
                VuoCompiler *otherCompiler = new VuoCompiler(moduleSearchPath + "/unused", target);
 
                dispatch_sync(environmentQueue, ^{
                    otherCompiler->loadModulesAndSources(set<string>(), set<string>(), set<string>(),
                                                         sourcesDepOnModulesAdded_otherCompiler[env], set<string>(), set<string>(),
                                                         false, true, env, nullptr, nullptr, "");
                });
 
                delete otherCompiler;
            });
        }
    }
 
    set<dispatch_group_t> sourcesLoading;
    for (vector< vector<Environment *> >::iterator i = environments.begin(); i != environments.end(); ++i)
    {
        Environment *env = (*i).at(0);
 
        set<string> sourcesToCompile;
        sourcesToCompile.insert(sourcesAdded[env].begin(), sourcesAdded[env].end());
        sourcesToCompile.insert(sourcesModified[env].begin(), sourcesModified[env].end());
 
        if (sourcesToCompile.size() == 0)
            continue;
 
        set<dispatch_group_t> s = env->compileModulesFromSourceCode(sourcesToCompile, shouldRecompileSourcesIfUnchanged);
        sourcesLoading.insert(s.begin(), s.end());
    }
 
    for (vector< vector<Environment *> >::iterator i = environments.begin(); i != environments.end(); ++i)
    {
        Environment *env = (*i).at(0);
 
        set<string> sourcesToCompile;
        sourcesToCompile.insert(sourcesDepOnModulesAdded[env].begin(), sourcesDepOnModulesAdded[env].end());
        sourcesToCompile.insert(sourcesDepOnModulesModified[env].begin(), sourcesDepOnModulesModified[env].end());
 
        if (sourcesToCompile.size() == 0)
            continue;
 
        env->compileModulesFromSourceCode(sourcesToCompile, true);
    }
 
    // Notify compiler delegates.
 
    for (vector< vector<Environment *> >::iterator i = environments.begin(); i != environments.end(); ++i)
    {
        Environment *env = (*i).at(0);
        env->notifyCompilers(actualModulesAdded[env], actualModulesModified[env], actualModulesRemoved[env], issues[env]);
    }
 
    // Since the dispatch groups for specialized modules are temporary (caller is responsible for releasing them)
    // but the dispatch groups for module sources should stay alive as long as the ModuleInfo that contains them,
    // retain the dispatch groups for module sources so that all dispatch groups can be safely released by the caller.
 
    for (const dispatch_group_t &group : sourcesLoading)
        dispatch_retain(group);
 
    set<dispatch_group_t> loadingGroups;
    loadingGroups.insert(specializedModulesLoading.begin(), specializedModulesLoading.end());
    loadingGroups.insert(sourcesLoading.begin(), sourcesLoading.end());
    return loadingGroups;
}
 
void VuoCompiler::findDependentModulesAndSources(map<Environment *, set<string> > &changedModules,
                                                 const vector<VuoDirectedAcyclicNetwork *> &searchDependencyGraphs,
                                                 VuoDirectedAcyclicGraph *currentEnvironmentDependencyGraph,
                                                 map<Environment *, set<string> > &modulesDepOnChangedModules_this,
                                                 map<Environment *, set<string> > &modulesDepOnChangedModules_other,
                                                 map<Environment *, set<string> > &sourcesDepOnChangedModules_this,
                                                 map<Environment *, set<string> > &sourcesDepOnChangedModules_other)
{
    for (const vector<Environment *> &envs : environments)
    {
        Environment *env = envs.at(0);
 
        for (const string &module : changedModules[env])
        {
            set<VuoDirectedAcyclicGraph::Vertex *> dependents;
            for (VuoDirectedAcyclicNetwork *searchDependencyGraph : searchDependencyGraphs)
            {
                vector<VuoDirectedAcyclicGraph::Vertex *> moduleVertices;
                if (currentEnvironmentDependencyGraph)
                {
                    // If a module with the same module key is installed in multiple locations,
                    // only consider the one being modified or removed.
                    VuoDirectedAcyclicGraph::Vertex *mv = currentEnvironmentDependencyGraph->findVertex(module);
                    if (mv)
                        moduleVertices.push_back(mv);
                }
                else
                    moduleVertices = searchDependencyGraph->findVertex(module);
 
                for (VuoDirectedAcyclicGraph::Vertex *moduleVertexRaw : moduleVertices)
                {
                    DependencyGraphVertex *moduleVertex = static_cast<DependencyGraphVertex *>(moduleVertexRaw);
                    if (moduleVertex->getEnvironment())
                    {
                        vector<VuoDirectedAcyclicGraph::Vertex *> upstream = searchDependencyGraph->getUpstreamVertices(moduleVertex);
                        dependents.insert(upstream.begin(), upstream.end());
                    }
                }
            }
 
            set< pair<Environment *, string> > dependentsMap;
            for (VuoDirectedAcyclicGraph::Vertex *dependentVertexRaw : dependents)
            {
                DependencyGraphVertex *v = static_cast<DependencyGraphVertex *>(dependentVertexRaw);
                Environment *dependentEnv = v->getEnvironment();
                if (! dependentEnv)
                    continue;
 
                string dependent = v->getDependency();
 
                dependentsMap.insert({dependentEnv, dependent});
            }
 
            // In case `module` is a generic node class, check the generated environment at the same scope for any
            // specializations of the node class, and add them to the list of dependencies.
            // (They aren't in the dependency graph since the graph edge goes from installed to generated.)
            for (auto i : envs.at(1)->getNodeClasses())
            {
                VuoCompilerSpecializedNodeClass *specializedNodeClass = dynamic_cast<VuoCompilerSpecializedNodeClass *>(i.second);
                if (specializedNodeClass->getOriginalGenericNodeClassName() == module)
                    dependentsMap.insert({envs.at(1), i.first});
            }
 
            for (auto i : dependentsMap)
            {
                Environment *dependentEnv = i.first;
                string dependent = i.second;
 
                // Skip if the dependent module is already being modified/removed in its own right
                // (e.g. if the module depends on another in the same node set and the node set is being removed).
                if (changedModules[dependentEnv].find(dependent) != changedModules[dependentEnv].end())
                    continue;
 
                ModuleInfo *foundSourceInfo = dependentEnv->listSourceFile(dependent);
                ModuleInfo *foundModuleInfo = dependentEnv->listModule(dependent);
 
                bool belongsToCurrentCompiler = false;
                for (const vector<Environment *> &envs2 : environments)
                {
                    if (find(envs2.begin(), envs2.end(), dependentEnv) != envs2.end())
                    {
                        belongsToCurrentCompiler = true;
                        break;
                    }
                }
 
                map<Environment *, set<string> > *whicheverDependents = nullptr;
                ModuleInfo *moduleInfo = nullptr;
                if (foundSourceInfo)
                {
                    moduleInfo = foundSourceInfo;
                    whicheverDependents = (belongsToCurrentCompiler ? &sourcesDepOnChangedModules_this : &sourcesDepOnChangedModules_other);
                }
                else if (foundModuleInfo)
                {
                    moduleInfo = foundModuleInfo;
                    whicheverDependents = (belongsToCurrentCompiler ? &modulesDepOnChangedModules_this : &modulesDepOnChangedModules_other);
                }
                else  // Module in generated environment
                {
                    whicheverDependents = (belongsToCurrentCompiler ? &modulesDepOnChangedModules_this : &modulesDepOnChangedModules_other);
                }
 
                (*whicheverDependents)[dependentEnv].insert(dependent);
                if (moduleInfo)
                    moduleInfo->setAttempted(false);
            }
        }
    }
}
 
void VuoCompiler::loadedModules(map<string, VuoCompilerModule *> modulesAdded,
                                map<string, pair<VuoCompilerModule *, VuoCompilerModule *> > modulesModified,
                                map<string, VuoCompilerModule *> modulesRemoved,
                                VuoCompilerIssues *issues, void *delegateDataV, Environment *currentEnvironment)
{
    //VLog("C=%p                   %lu %lu %lu", this, modulesAdded.size(), modulesModified.size(), modulesRemoved.size());
 
    // If a module is added, superseding a version of the same module installed at a broader scope,
    // notify this VuoCompiler that the module has been modified rather than added.
    //
    // If a module is added, but a version of the same module is already installed at a narrower scope,
    // don't notify this VuoCompiler, since it will continue to use the version at the narrower scope.
    //
    // Same idea when a module is modified or removed while another version is installed at a different scope.
 
    auto findVersionsOfModule = [this, currentEnvironment] (const string &moduleKey)
    {
        vector< pair<Environment *, VuoCompilerModule *> > moduleVersions;
        for (const vector<Environment *> &envs : environments)
        {
            Environment *env = envs.at(0);
            VuoCompilerModule *module = env->findModule(moduleKey);
            if (module || env == currentEnvironment)
                moduleVersions.push_back( make_pair(env, module) );
        }
        return moduleVersions;
    };
 
    for (map<string, VuoCompilerModule *>::iterator i = modulesAdded.begin(); i != modulesAdded.end(); )
    {
        string moduleKey = i->first;
        VuoCompilerModule *moduleAdded = i->second;
 
        vector< pair<Environment *, VuoCompilerModule *> > moduleVersions = findVersionsOfModule(moduleKey);
 
        if (moduleVersions.size() > 1)
        {
            modulesAdded.erase(i++);
 
            if (moduleVersions.back().second == moduleAdded)
            {
                VuoCompilerModule *moduleSuperseded = moduleVersions.at(moduleVersions.size()-2).second;
                modulesModified[moduleKey] = make_pair(moduleSuperseded, moduleAdded);
            }
        }
        else
            ++i;
    }
 
    for (map<string, pair<VuoCompilerModule *, VuoCompilerModule *> >::iterator i = modulesModified.begin(); i != modulesModified.end(); )
    {
        string moduleKey = i->first;
        VuoCompilerModule *moduleModified = i->second.second;
 
        vector< pair<Environment *, VuoCompilerModule *> > moduleVersions = findVersionsOfModule(moduleKey);
 
        if (moduleVersions.size() > 1 && moduleVersions.back().second != moduleModified)
            modulesModified.erase(i++);
        else
            ++i;
    }
 
    for (map<string, VuoCompilerModule *>::iterator i = modulesRemoved.begin(); i != modulesRemoved.end(); )
    {
        string moduleKey = i->first;
        VuoCompilerModule *moduleRemoved = i->second;
 
        vector< pair<Environment *, VuoCompilerModule *> > moduleVersions = findVersionsOfModule(moduleKey);
 
        if (moduleVersions.size() > 1)
        {
            modulesRemoved.erase(i++);
 
            if (moduleVersions.back().first == currentEnvironment)
            {
                VuoCompilerModule *moduleUnsuperseded = moduleVersions.at(moduleVersions.size()-2).second;
                modulesModified[moduleKey] = make_pair(moduleRemoved, moduleUnsuperseded);
            }
        }
        else
            ++i;
    }
 
    dispatch_async(delegateQueue, ^{
                       VuoCompilerDelegate::LoadedModulesData *delegateData = static_cast<VuoCompilerDelegate::LoadedModulesData *>(delegateDataV);
 
                       if (delegate && ! (modulesAdded.empty() && modulesModified.empty() && modulesRemoved.empty() && issues->isEmpty()))
                       {
                           delegate->enqueueData(delegateData);
                           delegate->loadedModules(modulesAdded, modulesModified, modulesRemoved, issues);
                       }
                       else
                       {
                           delegateData->release();
                       }
                   });
}
 
void VuoCompiler::loadNodeClassGeneratedAtRuntime(VuoCompilerNodeClass *nodeClass, Environment *env)
{
    Module *module = nodeClass->getModule();
    if (module)
    {
        dispatch_sync(llvmQueue, ^{
            setTargetForModule(nodeClass->getModule(), env->getTarget());
        });
    }
 
    dispatch_sync(environmentQueue, ^{
        env->replaceNodeClass(nodeClass);
    });
 
    __block map<string, VuoCompilerType *> inheritedTypes;
    void (^envReifyPortTypes)(Environment *) = ^void (Environment *env) {
        env->reifyPortTypes(inheritedTypes);
        map<string, VuoCompilerType *> currentTypes = env->getTypes();
        inheritedTypes.insert(currentTypes.begin(), currentTypes.end());
    };
    applyToAllEnvironments(envReifyPortTypes);
}
 
void VuoCompiler::reifyGenericPortTypes(VuoCompilerComposition *composition)
{
    for (VuoCompilerNode *node : composition->getCachedGraph(this)->getNodes())
        reifyGenericPortTypes(node->getBase());
 
    composition->invalidateCachedGraph();
}
 
void VuoCompiler::reifyGenericPortTypes(VuoNode *node)
{
    VuoCompilerSpecializedNodeClass *nodeClass = dynamic_cast<VuoCompilerSpecializedNodeClass *>(node->getNodeClass()->getCompiler());
    if (! nodeClass)
        return;
 
    // Reify any generic types on the node that don't already have a compiler detail.
 
    vector<VuoPort *> inputPorts = node->getInputPorts();
    vector<VuoPort *> outputPorts = node->getOutputPorts();
    vector<VuoPort *> ports;
    ports.insert(ports.end(), inputPorts.begin(), inputPorts.end());
    ports.insert(ports.end(), outputPorts.begin(), outputPorts.end());
 
    for (vector<VuoPort *>::iterator j = ports.begin(); j != ports.end(); ++j)
    {
        VuoCompilerPort *port = static_cast<VuoCompilerPort *>((*j)->getCompiler());
        VuoGenericType *genericType = dynamic_cast<VuoGenericType *>(port->getDataVuoType());
        if (! genericType)
            continue;
 
        if (! genericType->hasCompiler())
        {
            VuoCompilerType * (^compilerGetType)(string) = ^VuoCompilerType * (string moduleKey) {
                return getType(moduleKey);
            };
 
            VuoCompilerGenericType *reifiedType = VuoCompilerGenericType::newGenericType(genericType, compilerGetType);
            if (reifiedType)
                port->setDataVuoType(reifiedType->getBase());
        }
    }
 
    // Update the node class's backing to match the node's backing.
 
    nodeClass->updateBackingNodeClass(node, this);
}
 
void VuoCompiler::compileModule(string inputPath, string outputPath)
{
    compileModule(inputPath, outputPath, vector<string>());
}
 
void VuoCompiler::compileModule(string inputPath, string outputPath, const vector<string> &includePaths)
{
    if (isVerbose)
        print();
 
    vector<string> allIncludePaths = includePaths;
    string preprocessedInputPath = inputPath;
 
    string tmpPreprocessedInputDir;
    string dir, file, ext;
    VuoFileUtilities::splitPath(inputPath, dir, file, ext);
    if (VuoFileUtilities::isCSourceExtension(ext))
    {
        string inputContents = VuoFileUtilities::readFileToString(inputPath);
        string preprocessedInputContents = inputContents;
        VuoCompilerSpecializedNodeClass::replaceGenericTypesWithBacking(preprocessedInputContents);
        if (inputContents != preprocessedInputContents)
        {
            // Unspecialized generic node class
            allIncludePaths.push_back(dir.empty() ? "." : dir);
            tmpPreprocessedInputDir = VuoFileUtilities::makeTmpDir(file);
            preprocessedInputPath = tmpPreprocessedInputDir + "/" + file + "." + ext;
            VuoFileUtilities::preserveOriginalFileName(preprocessedInputContents, file + "." + ext);
            VuoFileUtilities::writeStringToFile(preprocessedInputContents, preprocessedInputPath);
        }
    }
    else if (ext == "fs")
    {
        VuoFileUtilities::File vuf(dir, file + "." + ext);
        VuoModuleCompiler *moduleCompiler = VuoModuleCompiler::newModuleCompiler("isf", getModuleKeyForPath(inputPath), &vuf);
        if (moduleCompiler)
        {
            auto getType = [this] (const string &moduleKey) { return this->getType(moduleKey); };
            VuoCompilerIssues *issues = new VuoCompilerIssues();
            Module *module = moduleCompiler->compile(getType, llvmQueue, issues);
            if (module)
                dispatch_sync(llvmQueue, ^{
                    setTargetForModule(module, target);
                    writeModuleToBitcode(module, outputPath);
#if VUO_PRO
                    string dependencyOutputPath = _dependencyOutput();
                    if (!dependencyOutputPath.empty())
                    {
                        string outputObjectPath = dependencyOutputPath.substr(0, dependencyOutputPath.length() - 2);
                        VuoFileUtilities::writeStringToFile(outputObjectPath + ": " + inputPath, dependencyOutputPath);
                    }
#endif
                });
 
            if (!issues->isEmpty())
                throw VuoCompilerException(issues, true);
            delete issues;
        }
        return;
    }
 
    vector<string> extraArgs;
    for (vector<string>::iterator i = allIncludePaths.begin(); i != allIncludePaths.end(); ++i)
    {
        extraArgs.push_back("-I");
        extraArgs.push_back(*i);
    }
 
 
    // When compiling on a development workstation or Jenkins, use the Conan-packaged macOS SDK, since it includes headers.
    // When compiling on an end-user system, no SDK is needed.
    string buildTimeMacOSSDKFolder = MACOS_SDK_ROOT;
    if (VuoFileUtilities::fileExists(buildTimeMacOSSDKFolder))
    {
        extraArgs.push_back("-isysroot");
        extraArgs.push_back(buildTimeMacOSSDKFolder);
    }
 
 
    __block vector<string> headerSearchPaths;
    void (^envGetHeaderSearchPaths)(Environment *) = ^void (Environment *env) {
        vector<string> result = env->getHeaderSearchPaths();
        headerSearchPaths.insert(headerSearchPaths.end(), result.begin(), result.end());
    };
    applyToInstalledEnvironments(envGetHeaderSearchPaths);
 
    auto issues = new VuoCompilerIssues;
    __block Module *module;
    dispatch_sync(llvmQueue, ^{
                      module = readModuleFromC(preprocessedInputPath, headerSearchPaths, extraArgs, issues);
                  });
    string moduleKey = getModuleKeyForPath(inputPath);
    if (! tmpPreprocessedInputDir.empty())
    {
        remove(tmpPreprocessedInputDir.c_str());
        issues->setFilePath(inputPath);
    }
    if (! module)
        throw VuoCompilerException(issues, true);
    delete issues;
 
    dispatch_sync(llvmQueue, ^{
                      VuoCompilerModule *compilerModule = VuoCompilerModule::newModule(moduleKey, module, "", VuoCompilerCompatibility::compatibilityWithAnySystem());
                      if (! compilerModule)
                      {
                          VUserLog("Error: Didn't recognize '%s' as a node class, type, or library.", inputPath.c_str());
                          return;
                      }
 
                      setTargetForModule(module, target);
                      writeModuleToBitcode(module, outputPath);
 
                      delete module;
                  });
}
 
Module * VuoCompiler::compileCompositionToModule(VuoCompilerComposition *composition, const string &moduleKey, bool isTopLevelComposition,
                                                 VuoCompilerIssues *issues)
{
    composition->check(issues);
 
    reifyGenericPortTypes(composition);
 
    VuoCompilerBitcodeGenerator *generator = VuoCompilerBitcodeGenerator::newBitcodeGeneratorFromComposition(composition,
                                                                                                             isTopLevelComposition,
                                                                                                             moduleKey, this);
 
    __block Module *module = nullptr;
    dispatch_sync(llvmQueue, ^{
        try
        {
            module = generator->generateBitcode();
            setTargetForModule(module, target);
        }
        catch (VuoCompilerException &e)
        {
            if (issues)
                issues->append(e.getIssues());
            else
                VUserLog("%s", e.getIssues()->getLongDescription(false).c_str());
        }
    });
 
    delete generator;
 
    return module;
}
 
void VuoCompiler::compileComposition(VuoCompilerComposition *composition, string outputPath, bool isTopLevelComposition,
                                     VuoCompilerIssues *issues)
{
    string moduleKey = getModuleKeyForPath(outputPath);
    Module *module = compileCompositionToModule(composition, moduleKey, isTopLevelComposition, issues);
    if (!module)
        throw VuoCompilerException(issues, false);
 
    dispatch_sync(llvmQueue, ^{
                      writeModuleToBitcode(module, outputPath);
                  });
}
 
void VuoCompiler::compileComposition(string inputPath, string outputPath, bool isTopLevelComposition,
                                     VuoCompilerIssues *issues)
{
    VUserLog("Compiling '%s' (%s)…", inputPath.c_str(), target.c_str());
    if (isVerbose)
        print();
 
    if (getCompositionLocalPath().empty())
        setCompositionPath(inputPath);
 
    if (!VuoFileUtilities::fileContainsReadableData(inputPath))
    {
        VuoCompilerIssue issue(VuoCompilerIssue::Error, "opening composition", inputPath,
                               "", "The composition file couldn't be read or was empty.");
        throw VuoCompilerException(issue);
    }
 
    try
    {
        string compositionString = VuoFileUtilities::readFileToString(inputPath);
        compileCompositionString(compositionString, outputPath, isTopLevelComposition, issues);
    }
    catch (VuoCompilerException &e)
    {
        if (e.getIssues())
            e.getIssues()->setFilePathIfEmpty(inputPath);
        if (!issues && e.getIssues())
            VUserLog("%s", e.getIssues()->getLongDescription(false).c_str());
        throw;
    }
 
    VUserLog("Done.");
}
 
void VuoCompiler::compileCompositionString(const string &compositionString, string outputPath, bool isTopLevelComposition,
                                           VuoCompilerIssues *issues)
{
    VuoCompilerComposition *composition = VuoCompilerComposition::newCompositionFromGraphvizDeclaration(compositionString, this);
    compileComposition(composition, outputPath, isTopLevelComposition, issues);
 
    VuoComposition *baseComposition = composition->getBase();
    delete composition;
    delete baseComposition;
}
 
void VuoCompiler::linkCompositionToCreateExecutable(string inputPath, string outputPath, Optimization optimization, string rPath, bool shouldAdHocCodeSign)
{
    vector<string> rPaths = ! rPath.empty() ? vector<string>(1, rPath) : getRunPathSearchPaths(environments.back().front());
    linkCompositionToCreateExecutableOrDynamicLibrary(inputPath, outputPath, optimization, false, rPaths, shouldAdHocCodeSign);
}
 
void VuoCompiler::linkCompositionToCreateDynamicLibrary(string inputPath, string outputPath, Optimization optimization, bool shouldAdHocCodeSign)
{
    vector<string> rPaths = getRunPathSearchPaths(environments.back().front());
    linkCompositionToCreateExecutableOrDynamicLibrary(inputPath, outputPath, optimization, true, rPaths, shouldAdHocCodeSign);
}
 
void VuoCompiler::linkCompositionToCreateExecutableOrDynamicLibrary(string compiledCompositionPath, string linkedCompositionPath,
                                                                    Optimization optimization, bool isDylib, const vector<string> &rPaths,
                                                                    bool shouldAdHocCodeSign)
{
    if (isVerbose)
        print();
 
    if (optimization == Optimization_FastBuildExistingCache)
        shouldLoadAllModules = false;
 
    set<string> dependencies = getDependenciesForComposition(compiledCompositionPath);
    dependencies.insert(getRuntimeDependency());
    if (! isDylib)
        dependencies.insert(getRuntimeMainDependency());
 
    set<Module *> modules;
    set<string> libraries;
    set<string> frameworks;
    getLinkerInputs(dependencies, optimization, modules, libraries, frameworks);
 
    libraries.insert(compiledCompositionPath);
 
    link(linkedCompositionPath, modules, libraries, frameworks, isDylib, rPaths, shouldAdHocCodeSign);
}
 
void VuoCompiler::linkCompositionToCreateDynamicLibraries(string compiledCompositionPath, string linkedCompositionPath,
                                                          VuoRunningCompositionLibraries *runningCompositionLibraries)
{
    if (isVerbose)
        print();
 
    bool shouldAdHocCodeSign = false;
#if __arm64__
    shouldAdHocCodeSign = true;
#endif
 
    // Get the dependencies used by the new resources and not the previous resources.
 
    set<string> carriedOverDependencies = runningCompositionLibraries->getDependenciesLoaded();
    set<string> allDependencies = getDependenciesForComposition(compiledCompositionPath);
    set<string> addedDependencies;
    std::set_difference(allDependencies.begin(), allDependencies.end(),
                        carriedOverDependencies.begin(), carriedOverDependencies.end(),
                        std::inserter(addedDependencies, addedDependencies.end()));
 
    // Get the libraries and frameworks used by the previous resources.
 
    vector<string> carriedOverNonUnloadableLibraries = runningCompositionLibraries->getNonUnloadableLibrariesLoaded();
    vector<string> carriedOverUnloadableLibraries = runningCompositionLibraries->getUnloadableLibrariesLoaded();
    set<string> carriedOverExternalLibraries = runningCompositionLibraries->getExternalLibraries();
    set<string> carriedOverFrameworks = runningCompositionLibraries->getExternalFrameworks();
 
    // Link the new resource dylibs, if needed.
 
    string nonUnloadableResourcePath;
    string unloadableResourcePath;
    set<string> nonUnloadableDependencies;
    set<string> unloadableDependencies;
    map<string, set<string> > builtInCacheDependencies;
    map<string, set<string> > userCacheDependencies;
    set<string> builtInLibraries;
    set<string> userLibraries;
    set<string> addedExternalLibraries;
    set<string> addedFrameworks;
    set<string> allFrameworks;
    if (! addedDependencies.empty())
    {
        // Get the modules, libraries, and frameworks that will provide the composition's dependencies.
 
        set<string> builtInModuleAndLibraryDependencies;
        set<string> userModuleAndLibraryDependencies;
        set<Module *> builtInModules;
        set<Module *> userModules;
 
        getLinkerInputs(addedDependencies, Optimization_FastBuild,
                        builtInModuleAndLibraryDependencies, userModuleAndLibraryDependencies, builtInCacheDependencies, userCacheDependencies,
                        builtInModules, userModules, builtInLibraries, userLibraries, addedExternalLibraries, addedFrameworks);
 
        allFrameworks.insert(carriedOverFrameworks.begin(), carriedOverFrameworks.end());
        allFrameworks.insert(addedFrameworks.begin(), addedFrameworks.end());
 
        string dir, linkedCompositionFile, ext;
        VuoFileUtilities::splitPath(linkedCompositionPath, dir, linkedCompositionFile, ext);
 
        // For any module caches that were rebuilt, remove the previous revision from the lists of libraries to link to and load.
 
        vector<string> carriedOverUserCacheLibraries = runningCompositionLibraries->getUnloadableCacheLibrariesLoaded();
 
        __block vector<string> currentCacheLibraries;
        applyToAllEnvironments(^void (Environment *env) {
            currentCacheLibraries.push_back( env->getCurrentModuleCacheDylib() );
        });
 
        for (string cachePath : carriedOverUserCacheLibraries)
        {
            for (string currentCachePath : currentCacheLibraries)
            {
                if (VuoFileUtilities::areDifferentRevisionsOfSameModuleCacheDylib(cachePath, currentCachePath))
                {
                    set<string> dependenciesInCache = runningCompositionLibraries->enqueueCacheLibraryToUnload(cachePath);
 
                    userCacheDependencies[currentCachePath].insert(dependenciesInCache.begin(), dependenciesInCache.end());
 
                    auto cacheDependenciesIter = userCacheDependencies.find(cachePath);
                    if (cacheDependenciesIter != userCacheDependencies.end())
                    {
                        userCacheDependencies[currentCachePath].insert(cacheDependenciesIter->second.begin(), cacheDependenciesIter->second.end());
                        userCacheDependencies.erase(cacheDependenciesIter);
                    }
 
                    auto carriedOverIter = find(carriedOverUnloadableLibraries.begin(), carriedOverUnloadableLibraries.end(), cachePath);
                    if (carriedOverIter != carriedOverUnloadableLibraries.end())
                        *carriedOverIter = currentCachePath;
                }
            }
        }
 
        // If any module caches were rebuilt, prepare to replace the existing user resource dylibs with the new resource dylib created below.
 
        bool wasModuleCacheRebuilt = runningCompositionLibraries->hasCacheLibraryEnqueuedToUnload();
        if (wasModuleCacheRebuilt)
        {
            vector<string> carriedOverResourceLibraries = runningCompositionLibraries->getUnloadableResourceLibrariesLoaded();
 
            vector<string> carriedOverUnloadableMinusResourceLibraries;
            std::set_difference(carriedOverUnloadableLibraries.begin(), carriedOverUnloadableLibraries.end(),
                                carriedOverResourceLibraries.begin(), carriedOverResourceLibraries.end(),
                                std::back_inserter(carriedOverUnloadableMinusResourceLibraries));
 
            carriedOverUnloadableLibraries = carriedOverUnloadableMinusResourceLibraries;
 
            set<string> dependenciesInResourceLibraries = runningCompositionLibraries->enqueueAllUnloadableResourceLibrariesToUnload();
            userModuleAndLibraryDependencies.insert(dependenciesInResourceLibraries.begin(), dependenciesInResourceLibraries.end());
 
            set<string> builtInModuleAndLibraryDependencies_tmp;
            set<string> userModuleAndLibraryDependencies_tmp;
            map<string, set<string> > builtInCacheDependencies_tmp;
            set<Module *> builtInModules_tmp;
            set<string> builtInLibraries_tmp;
            set<string> externalLibraries_tmp;
            set<string> externalFrameworks_tmp;
 
            getLinkerInputs(userModuleAndLibraryDependencies, Optimization_FastBuild,
                            builtInModuleAndLibraryDependencies_tmp, userModuleAndLibraryDependencies_tmp, builtInCacheDependencies_tmp, userCacheDependencies,
                            builtInModules_tmp, userModules, builtInLibraries_tmp, userLibraries, externalLibraries_tmp, externalFrameworks_tmp);
        }
 
        // If built-in dependencies were added, create an additional resource dylib.
 
        if (! builtInModules.empty() || builtInLibraries.size() > builtInCacheDependencies.size())
        {
            nonUnloadableResourcePath = VuoFileUtilities::makeTmpFile(linkedCompositionFile + "-resource-nonunloadable", "dylib");
            nonUnloadableDependencies = builtInModuleAndLibraryDependencies;
 
            set<string> librariesForNonUnloadableResource = builtInLibraries;
            librariesForNonUnloadableResource.insert(carriedOverNonUnloadableLibraries.begin(), carriedOverNonUnloadableLibraries.end());
            librariesForNonUnloadableResource.insert(carriedOverExternalLibraries.begin(), carriedOverExternalLibraries.end());
            librariesForNonUnloadableResource.insert(addedExternalLibraries.begin(), addedExternalLibraries.end());
 
            vector<string> rPaths = getRunPathSearchPaths(environments.front().front());
 
            link(nonUnloadableResourcePath, builtInModules, librariesForNonUnloadableResource, allFrameworks, true, rPaths, shouldAdHocCodeSign);
 
            for (set<string>::iterator i = builtInLibraries.begin(); i != builtInLibraries.end(); )
            {
                if (! VuoStringUtilities::endsWith(*i, ".dylib"))
                    builtInLibraries.erase(i++);
                else
                    i++;
            }
 
            for (set<string>::iterator i = addedExternalLibraries.begin(); i != addedExternalLibraries.end(); )
            {
                if (! VuoStringUtilities::endsWith(*i, ".dylib"))
                    addedExternalLibraries.erase(i++);
                else
                    i++;
            }
        }
 
        // If user dependencies were added or module caches were rebuilt, create an additional resource dylib.
 
        if (! userModules.empty() || userLibraries.size() > userCacheDependencies.size() || wasModuleCacheRebuilt)
        {
            unloadableResourcePath = VuoFileUtilities::makeTmpFile(linkedCompositionFile + "-resource-unloadable", "dylib");
            unloadableDependencies = userModuleAndLibraryDependencies;
 
            set<string> librariesForUnloadableResource = userLibraries;
            librariesForUnloadableResource.insert(builtInLibraries.begin(), builtInLibraries.end());
            librariesForUnloadableResource.insert(carriedOverUnloadableLibraries.begin(), carriedOverUnloadableLibraries.end());
            librariesForUnloadableResource.insert(carriedOverNonUnloadableLibraries.begin(), carriedOverNonUnloadableLibraries.end());
            librariesForUnloadableResource.insert(carriedOverExternalLibraries.begin(), carriedOverExternalLibraries.end());
            librariesForUnloadableResource.insert(addedExternalLibraries.begin(), addedExternalLibraries.end());
            if (! nonUnloadableResourcePath.empty())
                librariesForUnloadableResource.insert(nonUnloadableResourcePath);
 
            // This is usually correct, but may fail in the case where there are two identically-named dylibs at different
            // levels of scope. However, it's the best we can do as long as modules at the system, user, and composition
            // levels of scope are all combined into one resource dylib. (https://b33p.net/kosada/vuo/vuo/-/merge_requests/196#note_2148884)
            vector<string> rPaths = getRunPathSearchPaths(environments.back().front());
 
            link(unloadableResourcePath, userModules, librariesForUnloadableResource, allFrameworks, true, rPaths, shouldAdHocCodeSign);
 
            for (set<string>::iterator i = userLibraries.begin(); i != userLibraries.end(); )
            {
                if (! VuoStringUtilities::endsWith(*i, ".dylib"))
                    userLibraries.erase(i++);
                else
                    i++;
            }
        }
    }
 
    // Get the Vuo runtime dependency.
 
    set<string> vuoRuntimePaths;
    {
        set<Module *> modules;
        set<string> libraries;
        set<string> frameworks;
 
        set<string> dependencies;
        dependencies.insert(getRuntimeDependency());
        getLinkerInputs(dependencies, Optimization_FastBuild, modules, libraries, frameworks);
        vuoRuntimePaths = libraries;
    }
 
    // Link the composition.
 
    {
        set<Module *> modules;
        set<string> libraries;
 
        libraries.insert(compiledCompositionPath);
        libraries.insert(carriedOverExternalLibraries.begin(), carriedOverExternalLibraries.end());
        libraries.insert(addedExternalLibraries.begin(), addedExternalLibraries.end());
        libraries.insert(carriedOverNonUnloadableLibraries.begin(), carriedOverNonUnloadableLibraries.end());
        libraries.insert(carriedOverUnloadableLibraries.begin(), carriedOverUnloadableLibraries.end());
        libraries.insert(builtInLibraries.begin(), builtInLibraries.end());
        libraries.insert(userLibraries.begin(), userLibraries.end());
        if (! nonUnloadableResourcePath.empty())
            libraries.insert(nonUnloadableResourcePath);
        if (! unloadableResourcePath.empty())
            libraries.insert(unloadableResourcePath);
        libraries.insert(vuoRuntimePaths.begin(), vuoRuntimePaths.end());
        vector<string> rPaths = getRunPathSearchPaths(environments.front().front());
        link(linkedCompositionPath, modules, libraries, allFrameworks, true, rPaths, shouldAdHocCodeSign);
    }
 
    // Now that we're past the point where an exception can be thrown, update the RunningCompositionLibraries.
 
    if (! nonUnloadableResourcePath.empty())
        runningCompositionLibraries->enqueueResourceLibraryToLoad(nonUnloadableResourcePath, nonUnloadableDependencies, false);
 
    if (! unloadableResourcePath.empty())
        runningCompositionLibraries->enqueueResourceLibraryToLoad(unloadableResourcePath, unloadableDependencies, true);
 
    for (map<string, set<string> >::iterator i = builtInCacheDependencies.begin(); i != builtInCacheDependencies.end(); ++i)
        runningCompositionLibraries->enqueueCacheLibraryToLoad(i->first, i->second, false);
 
    for (map<string, set<string> >::iterator i = userCacheDependencies.begin(); i != userCacheDependencies.end(); ++i)
        runningCompositionLibraries->enqueueCacheLibraryToLoad(i->first, i->second, true);
 
    runningCompositionLibraries->addExternalFrameworks(addedFrameworks);
    runningCompositionLibraries->addExternalLibraries(addedExternalLibraries);
}
 
set<string> VuoCompiler::getDependenciesForComposition(const string &compiledCompositionPath)
{
    double t0 = VuoLogGetTime();
 
    // Add the node classes in the top-level composition and their dependencies.
    __block set<string> directDependencies;
    string moduleKey = getModuleKeyForPath(compiledCompositionPath);
    Module *module = readModuleFromBitcode(compiledCompositionPath, getTargetArch(target));
    dispatch_sync(llvmQueue, ^{
                      VuoCompilerModule *compilerModule = VuoCompilerModule::newModule(moduleKey, module, "", VuoCompilerCompatibility::compatibilityWithAnySystem());
                      directDependencies = compilerModule->getDependencies();
                      delete compilerModule;
                      delete module;
                  });
 
    try
    {
        auto deps = getDependenciesForComposition(directDependencies, true);
        VUserLog("Gathering dependencies for '%s' took %5.2fs", compiledCompositionPath.c_str(), VuoLogGetTime() - t0);
        return deps;
    }
    catch (VuoCompilerException &e)
    {
        e.getIssues()->setFilePathIfEmpty(compiledCompositionPath);
        throw;
    }
}
 
set<string> VuoCompiler::getDirectDependenciesForComposition(VuoCompilerComposition *composition)
{
    set<string> directDependencies;
 
    set<VuoCompilerNode *> nodes = composition->getCachedGraph(this)->getNodes();
    for (VuoCompilerNode *node : nodes)
        if (node->getBase()->getNodeClass()->hasCompiler())
            directDependencies.insert( node->getBase()->getNodeClass()->getCompiler()->getDependencyName() );
 
    vector<VuoPublishedPort *> publishedInputPorts = composition->getBase()->getPublishedInputPorts();
    vector<VuoPublishedPort *> publishedOutputPorts = composition->getBase()->getPublishedOutputPorts();
    vector<VuoPublishedPort *> publishedPorts;
    publishedPorts.insert(publishedPorts.end(), publishedInputPorts.begin(), publishedInputPorts.end());
    publishedPorts.insert(publishedPorts.end(), publishedOutputPorts.begin(), publishedOutputPorts.end());
    for (VuoPublishedPort *publishedPort : publishedPorts)
    {
        if (publishedPort->getClass()->hasCompiler())
        {
            VuoType *portType = static_cast<VuoCompilerPortClass *>( publishedPort->getClass()->getCompiler() )->getDataVuoType();
            if (portType)
            {
                string dependency;
                VuoGenericType *genericType = dynamic_cast<VuoGenericType *>(portType);
                if (genericType)
                {
                    VuoGenericType::Compatibility compatibility;
                    vector<string> compatibleTypeNames = genericType->getCompatibleSpecializedTypes(compatibility);
                    dependency = VuoCompilerGenericType::chooseBackingTypeName(portType->getModuleKey(), compatibleTypeNames);
                }
                else
                    dependency = portType->getModuleKey();
 
                directDependencies.insert(dependency);
            }
        }
    }
 
    return directDependencies;
}
 
set<string> VuoCompiler::getDependenciesForComposition(VuoCompilerComposition *composition)
{
    set<string> directDependencies = getDirectDependenciesForComposition(composition);
    return getDependenciesForComposition(directDependencies, false);
}
 
set<string> VuoCompiler::getDylibDependencyPathsForComposition(VuoCompilerComposition *composition)
{
    __block vector<string> librarySearchPaths;
    applyToInstalledEnvironments(^void (Environment *env) {
        vector<string> result = env->getLibrarySearchPaths();
        librarySearchPaths.insert(librarySearchPaths.end(), result.begin(), result.end());
    });
 
    set<string> dylibDeps;
    for (string dep : getDependenciesForComposition(composition))
    {
        string path = getLibraryPath(dep, librarySearchPaths);
        if (VuoStringUtilities::endsWith(path, ".dylib"))
            dylibDeps.insert(path);
    }
 
    return dylibDeps;
}
 
set<string> VuoCompiler::getDependenciesForComposition(const set<string> &directDependencies, bool checkCompatibility)
{
    // Make sure that any compiler-generated node classes have been generated and added to the dependency graph.
    for (set<string>::const_iterator i = directDependencies.begin(); i != directDependencies.end(); ++i)
        getNodeClass(*i);
 
    set<string> dependencies;
    for (set<string>::iterator i = directDependencies.begin(); i != directDependencies.end(); ++i)
    {
        string moduleKey = *i;
 
        dependencies.insert(moduleKey);
 
        // First pass: Find all dependencies of the direct dependency that have been loaded so far.
        vector<VuoDirectedAcyclicGraph::Vertex *> firstPassVertices = dependencyGraph->findVertex(moduleKey);
        set<VuoDirectedAcyclicGraph::Vertex *> firstPassDependencies(firstPassVertices.begin(), firstPassVertices.end());
        for (vector<VuoDirectedAcyclicGraph::Vertex *>::iterator j = firstPassVertices.begin(); j != firstPassVertices.end(); ++j)
        {
            vector<VuoDirectedAcyclicGraph::Vertex *> downstream = dependencyGraph->getDownstreamVertices(*j);
            firstPassDependencies.insert(downstream.begin(), downstream.end());
        }
 
        // Make sure that any compiler-generated node classes in subcompositions have been generated and added to the dependency graph.
        for (set<VuoDirectedAcyclicGraph::Vertex *>::iterator j = firstPassDependencies.begin(); j != firstPassDependencies.end(); ++j)
        {
            DependencyGraphVertex *v = static_cast<DependencyGraphVertex *>(*j);
            getNodeClass(v->getDependency());
        }
 
        // Second pass: Find all dependencies of the direct dependency, this time including dependencies of the node classes just generated.
        vector<VuoDirectedAcyclicGraph::Vertex *> moduleVertices = dependencyGraph->findVertex(moduleKey);
        for (vector<VuoDirectedAcyclicGraph::Vertex *>::iterator j = moduleVertices.begin(); j != moduleVertices.end(); ++j)
        {
            vector<VuoDirectedAcyclicGraph::Vertex *> downstream = dependencyGraph->getDownstreamVertices(*j);
            for (VuoDirectedAcyclicGraph::Vertex *v : downstream)
                dependencies.insert( static_cast<DependencyGraphVertex *>(v)->getDependency() );
        }
    }
 
    // Check that the dependencies are compatible with the compiler's target.
    if (checkCompatibility)
    {
        VuoCompilerCompatibility neededCompatibility = VuoCompilerCompatibility::compatibilityWithTargetTriple(target);
        VuoCompilerCompatibility actualCompatibility = getCompatibilityOfDependencies(dependencies);
 
        if (! actualCompatibility.isCompatibleWith(neededCompatibility))
        {
            VuoCompilerIssues *issues = new VuoCompilerIssues;
            set<VuoCompilerNodeClass *> nodeClassesReported;
 
            for (string moduleKey : dependencies)
            {
                VuoCompilerModule *module = getModule(moduleKey);
                if (module && ! module->getCompatibleTargets().isCompatibleWith(neededCompatibility))
                {
                    vector<VuoCompilerNodeClass *> incompatibleNodeClasses;
 
                    VuoCompilerNodeClass *moduleAsNodeClass = dynamic_cast<VuoCompilerNodeClass *>(module);
                    if (moduleAsNodeClass)
                        incompatibleNodeClasses.push_back(moduleAsNodeClass);
                    else
                    {
                        vector<VuoDirectedAcyclicGraph::Vertex *> moduleVertices = dependencyGraph->findVertex(moduleKey);
                        for (VuoDirectedAcyclicGraph::Vertex *v : moduleVertices)
                        {
                            vector<VuoDirectedAcyclicGraph::Vertex *> upstream = dependencyGraph->getUpstreamVertices(v);
 
                            vector<string> upstreamModuleKeys;
                            std::transform(upstream.begin(), upstream.end(),
                                           std::back_inserter(upstreamModuleKeys),
                                           [](VuoDirectedAcyclicGraph::Vertex *u){ return static_cast<DependencyGraphVertex *>(u)->getDependency(); });
 
                            vector<string> potentialNodeClassNames;
                            std::set_intersection(directDependencies.begin(), directDependencies.end(),
                                                  upstreamModuleKeys.begin(), upstreamModuleKeys.end(),
                                                  std::back_inserter(potentialNodeClassNames));
 
                            for (string nodeClassName : potentialNodeClassNames)
                            {
                                VuoCompilerNodeClass *upstreamNodeClass = getNodeClass(nodeClassName);
                                if (upstreamNodeClass)
                                    incompatibleNodeClasses.push_back(upstreamNodeClass);
                            }
                        }
                    }
 
                    if (incompatibleNodeClasses.empty())
                    {
                        VuoCompilerIssue issue(VuoCompilerIssue::Error, "linking composition", "",
                                               "Dependencies incompatible with system",
                                               "%module is only compatible with " + module->getCompatibleTargets().toString() +
                                               ", so this composition can't run on " + neededCompatibility.toString() + ".");
                        issue.setModule(module->getPseudoBase());
                        issues->append(issue);
                    }
                    else
                    {
                        for (VuoCompilerNodeClass *nodeClass : incompatibleNodeClasses)
                        {
                            if (nodeClassesReported.find(nodeClass) != nodeClassesReported.end())
                                continue;
 
                            nodeClassesReported.insert(nodeClass);
 
                            VuoCompilerIssue issue(VuoCompilerIssue::Error, "linking composition", "",
                                                   "Nodes incompatible with system",
                                                   "%module is only compatible with " + module->getCompatibleTargets().toString() +
                                                   ", so this composition can't run on " + neededCompatibility.toString() + ".");
                            issue.setModule(nodeClass->getPseudoBase());
                            issues->append(issue);
                        }
                    }
                }
            }
 
            if (issues->isEmpty())
            {
                VuoCompilerIssue issue(VuoCompilerIssue::Error, "linking composition", "",
                                       "Dependencies incompatible with system",
                                       "Some dependencies of this composition are only compatible with " + actualCompatibility.toString() +
                                       ", so this composition can't run on " + neededCompatibility.toString() + ".");
                issues->append(issue);
            }
 
            throw VuoCompilerException(issues, true);
        }
    }
 
    // Add the libraries needed by every linked composition.
    vector<string> coreDependencies = getCoreVuoDependencies();
    dependencies.insert(coreDependencies.begin(), coreDependencies.end());
 
    return dependencies;
}
 
VuoCompilerCompatibility VuoCompiler::getCompatibilityOfDependencies(const set<string> &dependencies)
{
    VuoCompilerCompatibility compatibility(nullptr);
 
    for (string dependency : dependencies)
    {
        VuoCompilerModule *module = getModule(dependency);
        if (module)
            compatibility = compatibility.intersection(module->getCompatibleTargets());
    }
 
    return compatibility;
}
 
void VuoCompiler::getLinkerInputs(const set<string> &dependencies, Optimization optimization,
                                  set<Module *> &modules, set<string> &libraries, set<string> &frameworks)
{
    set<string> builtInModuleAndLibraryDependencies;
    set<string> userModuleAndLibraryDependencies;
    map<string, set<string> > builtInCacheDependencies;
    map<string, set<string> > userCacheDependencies;
    set<Module *> builtInModules;
    set<Module *> userModules;
    set<string> builtInLibraries;
    set<string> userLibraries;
    set<string> externalLibraries;
 
    getLinkerInputs(dependencies, optimization,
                    builtInModuleAndLibraryDependencies, userModuleAndLibraryDependencies, builtInCacheDependencies, userCacheDependencies,
                    builtInModules, userModules, builtInLibraries, userLibraries, externalLibraries, frameworks);
 
    modules.insert(builtInModules.begin(), builtInModules.end());
    modules.insert(userModules.begin(), userModules.end());
    libraries.insert(builtInLibraries.begin(), builtInLibraries.end());
    libraries.insert(userLibraries.begin(), userLibraries.end());
    libraries.insert(externalLibraries.begin(), externalLibraries.end());
}
 
void VuoCompiler::getLinkerInputs(const set<string> &dependencies, Optimization optimization,
                                  set<string> &builtInModuleAndLibraryDependencies, set<string> &userModuleAndLibraryDependencies,
                                  map<string, set<string> > &builtInCacheDependencies, map<string, set<string> > &userCacheDependencies,
                                  set<Module *> &builtInModules, set<Module *> &userModules,
                                  set<string> &builtInLibraries, set<string> &userLibraries,
                                  set<string> &externalLibraries, set<string> &externalFrameworks)
{
    bool shouldUseModuleCache = (optimization == Optimization_FastBuild || optimization == Optimization_FastBuildExistingCache);
    if (shouldUseModuleCache)
        useModuleCache(true, optimization == Optimization_FastBuildExistingCache);
 
    __block vector<string> librarySearchPaths;
    void (^envGetLibrarySearchPaths)(Environment *) = ^void (Environment *env) {
        vector<string> result = env->getLibrarySearchPaths();
        librarySearchPaths.insert(librarySearchPaths.end(), result.begin(), result.end());
    };
    applyToInstalledEnvironments(envGetLibrarySearchPaths);
 
    for (set<string>::iterator i = dependencies.begin(); i != dependencies.end(); ++i)
    {
        string dependency = *i;
 
        bool foundInCache = false;
        string moduleCachePath;
        bool isInBuiltInModuleCache = false;
        if (shouldUseModuleCache)
            foundInCache = findInModuleCache(dependency, moduleCachePath, isInBuiltInModuleCache);
 
        if (foundInCache)
        {
            if (isInBuiltInModuleCache)
            {
                builtInLibraries.insert(moduleCachePath);
                builtInCacheDependencies[moduleCachePath].insert(dependency);
            }
            else
            {
                userLibraries.insert(moduleCachePath);
                userCacheDependencies[moduleCachePath].insert(dependency);
            }
        }
        else
        {
            __block VuoCompilerModule *module = NULL;
            void (^envFindModule)(Environment *) = ^void (Environment *env) {
                VuoCompilerModule *result = env->findModule(dependency);
                if (result)
                    module = result;
            };
            applyToAllEnvironments(envFindModule);
 
            if (module)
            {
                VuoCompilerNodeClass *nodeClass = dynamic_cast<VuoCompilerNodeClass *>(module);
                if (! (nodeClass && VuoCompilerSpecializedNodeClass::hasGenericPortTypes(nodeClass)) )  // Skip not-fully-specialized generic modules
                {
                    string modulePath = module->getModulePath();
                    if (! modulePath.empty() && dynamic_cast<VuoCompilerType *>(module))
                    {
                        if (module->isBuiltIn())
                            builtInLibraries.insert(modulePath);
                        else
                            userLibraries.insert(modulePath);
                    }
                    else
                    {
                        if (module->isBuiltIn())
                            builtInModules.insert(module->getModule());
                        else
                            userModules.insert(module->getModule());
                    }
 
                    if (module->isBuiltIn())
                        builtInModuleAndLibraryDependencies.insert(dependency);
                    else
                        userModuleAndLibraryDependencies.insert(dependency);
                }
            }
            else
            {
                if (VuoStringUtilities::endsWith(dependency, ".framework"))
                    externalFrameworks.insert(dependency);
                else
                {
                    string dependencyPath = getLibraryPath(dependency, librarySearchPaths);
                    if (! dependencyPath.empty())
                        externalLibraries.insert(dependencyPath);
 
                    // On macOS 11, libc.dylib and libobjc.dylib are not present,
                    // but we can still link since Vuo.framework includes the TBDs.
                    else if (dependency != "c"
                          && dependency != "objc")
                        VUserLog("Warning: Could not locate dependency '%s'.", dependency.c_str());
                }
            }
        }
    }
}
 
string VuoCompiler::getLibraryPath(const string &dependency, vector<string> librarySearchPaths)
{
    if (dependency[0] == '/' && VuoFileUtilities::fileExists(dependency))
        return dependency;
 
    // Put the system library folder last in the list — prefer to use the libraries bundled in Vuo.framework.
    // Don't attempt to use OpenSSL from the system library folder, since macOS 10.15 prevents linking to it.
    if (dependency != "crypto"
     && dependency != "ssl")
         librarySearchPaths.push_back("/usr/lib");
 
    for (auto &path : librarySearchPaths)
    {
        vector<string> variations;
        variations.push_back(path + "/"    + dependency);
        variations.push_back(path + "/lib" + dependency);
        variations.push_back(path + "/lib" + dependency + ".dylib");
        variations.push_back(path + "/lib" + dependency + ".a");
        for (auto &variation : variations)
            if (VuoFileUtilities::fileExists(variation))
                return variation;
    }
 
    return "";
}
 
void VuoCompiler::useModuleCache(bool shouldUseExistingBuiltInCaches, bool shouldUseExistingOtherCaches)
{
    loadModulesIfNeeded();
    dispatch_group_wait(moduleSourceCompilersExist, DISPATCH_TIME_FOREVER);  // Wait for any previous loadModulesIfNeeded() calls to complete.
 
    // Iterate through the environments in the order that the caches need to be built.
 
    dispatch_sync(environmentQueue, ^{
                      set<string> dylibsForCachesOfInstalledModules;
                      set<string> frameworksForCachesOfInstalledModules;
                      unsigned long lastPrerequisiteModuleCacheRebuild = 0;
                      for (vector< vector<Environment *> >::iterator i = environments.begin(); i != environments.end(); ++i)
                      {
                          set<string> dylibsForCacheOfGeneratedModules;
                          set<string> frameworksForCacheOfGeneratedModules;
 
                          for (int j = i->size() - 1; j >= 0; --j)
                          {
                              Environment *env = i->at(j);
                              bool installed = (j == 0);
 
                              set<string> cacheableModulesAndDependencies;
                              set<string> dylibsNeededToLinkToThisCache;
                              set<string> frameworksNeededToLinkToThisCache;
                              env->getCacheableModulesAndDependencies(cacheableModulesAndDependencies,
                                                                      dylibsNeededToLinkToThisCache, frameworksNeededToLinkToThisCache);
 
                              set<string> accumulatedDylibs;
                              accumulatedDylibs.insert(dylibsNeededToLinkToThisCache.begin(), dylibsNeededToLinkToThisCache.end());
                              accumulatedDylibs.insert(dylibsForCachesOfInstalledModules.begin(), dylibsForCachesOfInstalledModules.end());
                              accumulatedDylibs.insert(dylibsForCacheOfGeneratedModules.begin(), dylibsForCacheOfGeneratedModules.end());
 
                              set<string> accumulatedFrameworks;
                              accumulatedFrameworks.insert(frameworksNeededToLinkToThisCache.begin(), frameworksNeededToLinkToThisCache.end());
                              accumulatedFrameworks.insert(frameworksForCachesOfInstalledModules.begin(), frameworksForCachesOfInstalledModules.end());
                              accumulatedFrameworks.insert(frameworksForCacheOfGeneratedModules.begin(), frameworksForCacheOfGeneratedModules.end());
 
                              bool shouldUseExistingCache = (env->isBuiltIn() ? shouldUseExistingBuiltInCaches : shouldUseExistingOtherCaches);
                              env->useModuleCache(shouldUseExistingCache, this, cacheableModulesAndDependencies,
                                                  accumulatedDylibs, accumulatedFrameworks, lastPrerequisiteModuleCacheRebuild);
 
                              string cacheDylib = env->getCurrentModuleCacheDylib();
                              accumulatedDylibs.insert(cacheDylib);
                              dylibsForCachesOfInstalledModules.insert(cacheDylib);
 
                              lastPrerequisiteModuleCacheRebuild = max(lastPrerequisiteModuleCacheRebuild, env->getLastModuleCacheRebuild());
 
                              if (installed)
                              {
                                  dylibsForCachesOfInstalledModules.insert(dylibsNeededToLinkToThisCache.begin(), dylibsNeededToLinkToThisCache.end());
                                  frameworksForCachesOfInstalledModules.insert(frameworksNeededToLinkToThisCache.begin(), frameworksNeededToLinkToThisCache.end());
                              }
                              else
                              {
                                  dylibsForCacheOfGeneratedModules.insert(dylibsNeededToLinkToThisCache.begin(), dylibsNeededToLinkToThisCache.end());
                                  frameworksForCacheOfGeneratedModules.insert(frameworksNeededToLinkToThisCache.begin(), frameworksNeededToLinkToThisCache.end());
                              }
                          }
                      }
                  });
 
    Environment::waitForModuleCachesToBuild();
}
 
bool VuoCompiler::findInModuleCache(const string &moduleOrDependency, string &cachePath, bool &isBuiltinCache)
{
    __block bool found = false;
    __block string outPath;
    __block bool outBuiltin;
    dispatch_sync(environmentQueue, ^{
                      for (vector< vector<Environment *> >::iterator i = environments.begin(); i != environments.end(); ++i)
                      {
                          bool builtin = (i == environments.begin());
 
                          for (int j = i->size() - 1; j >= 0; --j)
                          {
                              Environment *env = i->at(j);
 
                              string resultPath;
                              bool resultFound = env->findInModuleCache(moduleOrDependency, resultPath);
                              if (resultFound)
                              {
                                  found = true;
                                  outPath = resultPath;
                                  outBuiltin = builtin;
                              }
                          }
                      }
                  });
 
    cachePath = outPath;
    isBuiltinCache = outBuiltin;
    return found;
}
 
void VuoCompiler::prepareForFastBuild(void)
{
    dispatch_group_async(moduleCacheBuilding, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
                             useModuleCache(true, false);
                         });
}
 
string VuoCompiler::getTarget(void)
{
    return target;
}
 
string VuoCompiler::getArch(void)
{
    return getTargetArch(target);
}
 
void VuoCompiler::generateBuiltInModuleCaches(string vuoFrameworkPath, string target)
{
    vuoFrameworkInProgressPath = vuoFrameworkPath;
 
    VuoCompiler compiler("", target);
    compiler.useModuleCache(false, true);
}
 
void VuoCompiler::deleteOldModuleCaches(void)
{
    unsigned long maxSeconds = 30 * 24 * 60 * 60;  // 30 days
 
    set<VuoFileUtilities::File *> cacheDirs = VuoFileUtilities::findAllFilesInDirectory(VuoFileUtilities::getCachePath());
    for (set<VuoFileUtilities::File *>::iterator i = cacheDirs.begin(); i != cacheDirs.end(); ++i)
    {
        string path = (*i)->path();
 
        string file = (*i)->basename();
        if (file != "Builtin" && file != "System" && file != "User")
        {
            unsigned long fileSeconds = VuoFileUtilities::getSecondsSinceFileLastAccessed(path);
            if (fileSeconds > maxSeconds)
                VuoFileUtilities::deleteDir(path);
        }
 
        if (VuoStringUtilities::beginsWith(file, Environment::pidCacheDirPrefix))
        {
            string pidAsString = file.substr(Environment::pidCacheDirPrefix.length());
            int pid = atoi(pidAsString.c_str());
            if (kill(pid, 0) != 0)  // no running process has this pid
                VuoFileUtilities::deleteDir(path);
        }
 
        delete *i;
    }
}
 
void VuoCompiler::setLoadAllModules(bool shouldLoadAllModules)
{
    dispatch_sync(modulesToLoadQueue, ^{
                      this->shouldLoadAllModules = shouldLoadAllModules;
                  });
}
 
void VuoCompiler::link(string outputPath, const set<Module *> &modules, const set<string> &libraries, const set<string> &frameworks, bool isDylib, const vector<string> &rPaths, bool shouldAdHocCodeSign, VuoCompilerIssues *issues)
{
    VUserLog("Linking '%s' (%s)…", outputPath.c_str(), getTargetArch(target).c_str());
    // https://stackoverflow.com/questions/11657529/how-to-generate-an-executable-from-an-llvmmodule
 
    bool ownsIssues = false;
    if (! issues)
    {
        issues = new VuoCompilerIssues;
        ownsIssues = true;
    }
 
    // Write all the modules with renamed symbols to a composite module file (since the linker can't operate on in-memory modules).
    string compositeModulePath = VuoFileUtilities::makeTmpFile("composite", "bc");
    dispatch_sync(llvmQueue, ^{
                      double t0 = VuoLogGetTime();
 
                      unique_ptr<Module> compositeModule(new Module("composite", *globalLLVMContext));
                      Linker linker(*compositeModule);
                      setTargetForModule(compositeModule.get(), target);
 
                      for (auto i : modules)
                      {
                          unique_ptr<Module> upi = llvm::CloneModule(i);
                          if (linker.linkInModule(std::move(upi)))
                          {
                              VuoCompilerIssue issue(VuoCompilerIssue::IssueType::Error, "linking composite module", "",
                                                     "", "Failed to link in the module with ID '" + i->getModuleIdentifier() + "'");
                              issues->append(issue);
                          }
                      }
 
                      writeModuleToBitcode(compositeModule.get(), compositeModulePath);
 
                      VUserLog("\tLinkModules took %5.2fs", VuoLogGetTime() - t0);
                  });
 
 
    // llvm-3.1/llvm/tools/clang/tools/driver/driver.cpp
 
    // Invoke clang as `clang++` so it includes the C++ standard libraries.
    string clangPath(getClangPath() + "++");
 
    vector<const char *> args;
    vector<char *> argsToFree;
    args.push_back(clangPath.c_str());
 
    {
        char *outputPathZ = strdup(("-o" + outputPath).c_str());
        args.push_back(outputPathZ);
        argsToFree.push_back(outputPathZ);
    }
 
    args.push_back(compositeModulePath.c_str());
 
    vector<string> coreDependencies = getCoreVuoDependencies();
    for (set<string>::const_iterator i = libraries.begin(); i != libraries.end(); ++i)
    {
        string library = *i;
 
        for (vector<string>::iterator j = coreDependencies.begin(); j != coreDependencies.end(); ++j)
        {
            string coreDependency = *j;
            if (VuoStringUtilities::endsWith(library, "lib" + coreDependency + ".a"))
                args.push_back("-force_load");  // Load all symbols of static core dependencies, not just those used in the objects.
        }
 
        // Use the pre-built native object file if it exists (faster than converting .bc to .o every build).
        if (VuoStringUtilities::endsWith(library, ".bc"))
        {
            string libraryObject = VuoStringUtilities::substrBefore(library, ".bc") + ".o";
            if (VuoFileUtilities::fileExists(libraryObject))
                library = libraryObject;
        }
 
        char *libraryZ = strdup(library.c_str());
        args.push_back(libraryZ);
        argsToFree.push_back(libraryZ);
    }
 
    // Add framework search paths
    vector<string> frameworkArguments;
 
    __block vector<string> frameworkSearchPaths;
    void (^envGetFrameworkSearchPaths)(Environment *) = ^void (Environment *env) {
        vector<string> result = env->getFrameworkSearchPaths();
        frameworkSearchPaths.insert(frameworkSearchPaths.end(), result.begin(), result.end());
    };
    applyToInstalledEnvironments(envGetFrameworkSearchPaths);
 
    for (vector<string>::const_iterator i = frameworkSearchPaths.begin(); i != frameworkSearchPaths.end(); ++i)
    {
        string a = "-F"+*i;
        // Keep these std::strings around until after args is done being used, since the std::string::c_str() is freed when the std::string is deleted.
        frameworkArguments.push_back(a);
        char *frameworkArgument = strdup(a.c_str());
        args.push_back(frameworkArgument);
        argsToFree.push_back(frameworkArgument);
    }
 
    for (set<string>::const_iterator i = frameworks.begin(); i != frameworks.end(); ++i)
    {
        args.push_back("-framework");
 
        string frameworkName = *i;
        frameworkName = frameworkName.substr(0, frameworkName.length() - string(".framework").length());
        char *frameworkNameZ = strdup(frameworkName.c_str());
        args.push_back(frameworkNameZ);
        argsToFree.push_back(frameworkNameZ);
    }
 
    // When linking on a development workstation or Jenkins or an end-user system,
    // use the partial macOS SDK bundled in Vuo.framework, since it includes all the TBDs we need.
    string vuoFrameworkPath = getVuoFrameworkPath();
    string frameworkMacOSSDKFolder = vuoFrameworkPath + "/SDKs/MacOSX.sdk";
    if (!VuoFileUtilities::fileExists(frameworkMacOSSDKFolder))
        throw VuoException("Couldn't find the macOS SDK.");
 
    args.push_back("-Xlinker");
    args.push_back("-syslibroot");
    args.push_back("-Xlinker");
    char *frameworkMacOSSDKFolderZ = strdup(frameworkMacOSSDKFolder.c_str());
    args.push_back(frameworkMacOSSDKFolderZ);
    argsToFree.push_back(frameworkMacOSSDKFolderZ);
 
    args.push_back("-Xlinker");
    args.push_back("-platform_version");
    args.push_back("-Xlinker");
    args.push_back("macos");
    args.push_back("-Xlinker");
    char *deploymentTargetZ = strdup(MACOS_DEPLOYMENT_TARGET);
    args.push_back(deploymentTargetZ);
    argsToFree.push_back(deploymentTargetZ);
    args.push_back("-Xlinker");
    char *sdkVersionZ = strdup(MACOS_SDK_VERSION);
    args.push_back(sdkVersionZ);
    argsToFree.push_back(sdkVersionZ);
 
    // Linker option necessary for compatibility with our bundled version of ld64:
    args.push_back("-Xlinker");
    args.push_back("--no-demangle");
 
    if (isVerbose)
        args.push_back("-v");
 
    if (isDylib)
        args.push_back("-dynamiclib");
 
    args.push_back("-Xlinker");
    args.push_back("-headerpad_max_install_names");
 
    // Tell the built dylib/executable where to find dylibs that it depends on
    for (const string &rPath : rPaths)
    {
        args.push_back("-rpath");
        args.push_back(rPath.c_str());
    }
 
#ifdef COVERAGE
    args.push_back("-rpath");
    args.push_back(LLVM_ROOT "/lib");
#endif
 
    args.push_back("-target");
    args.push_back(target.c_str());
 
    args.push_back("-std=c++14");
    args.push_back("-stdlib=libc++");
    args.push_back("-mmacosx-version-min=10.10");
 
    // Allow clang to print meaningful error messages.
    auto diagnosticConsumer = new VuoCompilerDiagnosticConsumer(issues);
    clang::DiagnosticOptions *diagOptions = new clang::DiagnosticOptions();
    IntrusiveRefCntPtr<clang::DiagnosticIDs> DiagID(new clang::DiagnosticIDs());
    clang::DiagnosticsEngine Diags(DiagID, diagOptions, diagnosticConsumer);
 
    if (isVerbose)
    {
        ostringstream s;
        for (vector<const char *>::iterator i = args.begin(); i != args.end(); ++i)
            s << *i << " ";
        VUserLog("\t%s", s.str().c_str());
    }
 
    // Redirect linker output to a file, so we can feed it through VuoLog.
    string stdoutFile = VuoFileUtilities::makeTmpFile("vuo-linker-output", "txt");
    const StringRef stdoutPath(stdoutFile);
    const StringRef *redirects[] = {
        nullptr,      // stdin
        &stdoutPath,  // stdout
        &stdoutPath,  // stderr
    };
 
    // ExecuteAndWait's args needs to be null-terminated.
    const char **argsz = (const char **)malloc(sizeof(char *) * args.size() + 1);
    for (int i = 0; i < args.size(); ++i)
        argsz[i] = args[i];
    argsz[args.size()] = nullptr;
 
    string errMsg;
    bool executionFailed;
    double t0 = VuoLogGetTime();
    int ret = llvm::sys::ExecuteAndWait(args[0], argsz, nullptr, redirects, 0, 0, &errMsg, &executionFailed);
 
    for (auto i : argsToFree)
        free(i);
 
    // Clean up composite module file.
    remove(compositeModulePath.c_str());
 
    if (!isDylib)
        // Ensure the linked binary has the execute permission set
        // (ld64-242 doesn't reliably set it, whereas ld64-133.3 did).
        // https://b33p.net/kosada/node/14152
        chmod(outputPath.c_str(), 0755);
 
    if (ret != 0)
    {
        string details;
        if (!errMsg.empty())
        {
            VUserLog("%s", errMsg.c_str());
            details += "\n" + errMsg + "\n";
        }
        string stdoutFileContents = VuoFileUtilities::readFileToString(stdoutFile);
        if (!stdoutFileContents.empty())
        {
            VUserLog("%s", stdoutFileContents.c_str());
            details += "\n" + stdoutFileContents + "\n";
        }
        VuoFileUtilities::deleteFile(stdoutFile);
 
        VuoCompilerIssue issue(VuoCompilerIssue::Error, "linking composition", outputPath, "", details);
        issues->append(issue);
        throw VuoCompilerException(issues, ownsIssues);
    }
 
    VuoFileUtilities::deleteFile(stdoutFile);
    VUserLog("\tLinking     took %5.2fs", VuoLogGetTime() - t0);
 
    if (shouldAdHocCodeSign)
        adHocCodeSign(outputPath);
}
 
void VuoCompiler::adHocCodeSign(string path)
{
    VuoFileUtilities::adHocCodeSign(path, {
#if VUO_PRO
        "CODESIGN_ALLOCATE=" + getCodesignAllocatePath(),
#endif
    });
}
 
Module *VuoCompiler::readModuleFromC(string inputPath, const vector<string> &headerSearchPaths, const vector<string> &extraArgs, VuoCompilerIssues *issues)
{
    // llvm-3.1/llvm/tools/clang/examples/clang-interpreter/main.cpp
 
    vector<const char *> args;
    vector<char *> argsToFree;
 
    args.push_back(inputPath.c_str());
    args.push_back("-DVUO_COMPILER");
    args.push_back("-fblocks");
 
    // Provide full backtraces, for easier debugging using Instruments and `VuoLog_backtrace()`.
    // The Clang driver translates `-fno-omit-frame-pointer` to `clang -cc1`'s `-mdisable-fp-elim`.
    // In Clang 10, this was renamed to `-mframe-pointer=all`.
    // https://b33p.net/kosada/vuo/vuo/-/issues/19064
    args.push_back("-mdisable-fp-elim");
 
    // Sync with /CMakeLists.txt's `commonFlags`.
    args.push_back("-Wall");
    args.push_back("-Wextra");
    args.push_back("-Wimplicit-fallthrough");
    args.push_back("-Wno-unused-parameter");
    args.push_back("-Wno-sign-compare");
    args.push_back("-Werror=implicit");
 
    if (VuoStringUtilities::endsWith(inputPath, ".cc"))
    {
        args.push_back("-std=c++14");
        args.push_back("-stdlib=libc++");
        args.push_back("-fexceptions");
        args.push_back("-fcxx-exceptions");
    }
 
    for (vector<string>::const_iterator i = headerSearchPaths.begin(); i != headerSearchPaths.end(); ++i)
    {
        args.push_back("-I");
        args.push_back(i->c_str());
    }
 
#if VUO_PRO
    string dependencyOutputPath = _dependencyOutput();
    if (!dependencyOutputPath.empty())
    {
        char *outputObjectPath = strdup(dependencyOutputPath.substr(0, dependencyOutputPath.length() - 2).c_str());
        argsToFree.push_back(outputObjectPath);
 
        // https://bugzilla.mozilla.org/show_bug.cgi?id=1340588#c4
        // https://lists.llvm.org/pipermail/cfe-users/2018-March/001268.html
        args.push_back("-MT");
        args.push_back(outputObjectPath);
        args.push_back("-dependency-file");
        args.push_back(dependencyOutputPath.c_str());
    }
#endif
 
    if (isVerbose)
        args.push_back("-v");
 
    for (vector<string>::const_iterator i = extraArgs.begin(); i != extraArgs.end(); ++i)
        args.push_back(i->c_str());
 
    auto diagnosticConsumer = new VuoCompilerDiagnosticConsumer(issues);
    clang::DiagnosticOptions * diagOptions = new clang::DiagnosticOptions();
    IntrusiveRefCntPtr<clang::DiagnosticIDs> DiagID(new clang::DiagnosticIDs());
    clang::DiagnosticsEngine *diags = new clang::DiagnosticsEngine(DiagID, diagOptions, diagnosticConsumer);
 
    // This invokes `clang -cc1`.  See `clang -cc1 --help` for available options.
    shared_ptr<clang::CompilerInvocation> compilerInvocation(new clang::CompilerInvocation);
    clang::CompilerInvocation::CreateFromArgs(*compilerInvocation, &args[0], &args[0] + args.size(), *diags);
    compilerInvocation->TargetOpts->Triple = target;
 
    clang::CompilerInstance Clang;
    Clang.setInvocation(compilerInvocation);
 
    Clang.setDiagnostics(diags);
    if (!Clang.hasDiagnostics())
        return NULL;
 
    // See CompilerInvocation::GetResourcesPath -- though we're not calling it because we don't have MainAddr.
    string builtinHeaderSearchPath;
    string vuoFrameworkPath = getVuoFrameworkPath();
    if (vuoFrameworkPath.empty())
    {
        builtinHeaderSearchPath = getClangPath();
        if (VuoStringUtilities::endsWith(builtinHeaderSearchPath, "Helpers/clang"))
            builtinHeaderSearchPath = VuoStringUtilities::substrBefore(builtinHeaderSearchPath, "Helpers/clang");
        else if (VuoStringUtilities::endsWith(builtinHeaderSearchPath, "bin/clang"))
            builtinHeaderSearchPath = VuoStringUtilities::substrBefore(builtinHeaderSearchPath, "bin/clang");
        builtinHeaderSearchPath += "lib/clang/" CLANG_VERSION_STRING;
    }
    else
        builtinHeaderSearchPath = vuoFrameworkPath + "/Frameworks/llvm.framework/Versions/A/lib/clang/" CLANG_VERSION_STRING;
    Clang.getHeaderSearchOpts().ResourceDir = builtinHeaderSearchPath;
 
//  OwningPtr<clang::CodeGenAction> Act(new clang::EmitLLVMOnlyAction());  // @@@ return value of takeModule() is destroyed at the end of this function
    clang::CodeGenAction *Act = new clang::EmitLLVMOnlyAction();
    if (!Clang.ExecuteAction(*Act))
        return NULL;
 
    for (auto i : argsToFree)
        free(i);
 
    unique_ptr<Module> module = Act->takeModule();
    if (!module)
        VUserLog("Error compiling %s: module is null.", inputPath.c_str());
    return module.release();
}
 
Module *VuoCompiler::readModuleFromBitcode(string inputPath, string arch)
{
    string dir, file, ext;
    VuoFileUtilities::splitPath(inputPath, dir, file, ext);
    VuoFileUtilities::File inputFile(dir, file + "." + ext);
    return readModuleFromBitcode(&inputFile, arch);
}
 
Module *VuoCompiler::readModuleFromBitcode(VuoFileUtilities::File *inputFile, string arch)
{
    size_t inputDataBytes;
    char *inputData = inputFile->getContentsAsRawData(inputDataBytes);
 
    string error;
    set<string> availableArchs;
    VuoLog_status("Loading module \"%s\" (%s)", inputFile->getRelativePath().c_str(), arch.c_str());
    Module *module = readModuleFromBitcodeData(inputData, inputDataBytes, arch, availableArchs, error);
    VuoLog_status(NULL);
    if (! module)
        VUserLog("Error: Couldn't parse module '%s' (%s): %s.", inputFile->getRelativePath().c_str(), arch.c_str(), error.c_str());
 
    free(inputData);
 
    return module;
}
 
Module *VuoCompiler::readModuleFromBitcodeData(char *inputData, size_t inputDataBytes, string arch,
                                               set<string> &availableArchs, string &error)
{
    if (inputDataBytes < sizeof(unsigned int))
        return nullptr;
 
    __block Module *module = nullptr;
    dispatch_sync(llvmQueue, ^{
        StringRef inputDataAsStringRef(inputData, inputDataBytes);
        auto mb = MemoryBuffer::getMemBuffer(inputDataAsStringRef, "", false);
        if (!mb)
        {
            error = "Couldn't create MemoryBuffer";
            return;
        }
 
        MemoryBufferRef bitcodeBuffer;
        string moduleArch;
        unsigned int fileID = *(unsigned int *)inputData;
        if (fileID == 0x0b17c0de)
            // This is a single-architecture LLVM bitcode `.bc` file, so read the entire file.
            bitcodeBuffer = mb.get()->getMemBufferRef();
 
        else if (fileID == 0xdec04342)
        {
            // This is a single-architecture raw bitcode file, presumably generated by Vuo 2.2.1 or earlier.
            bitcodeBuffer = mb.get()->getMemBufferRef();
            moduleArch = "x86_64";
            availableArchs.insert(moduleArch);
        }
 
        else if (fileID == 0xbebafeca)
        {
            if (arch.empty())
            {
                error = "It's a Mach-O universal binary, but this compiler instance's LLVM target isn't set";
                return;
            }
 
            // This is a Mach-O wrapper around multiple LLVM bitcode files;
            // parse the Mach-O header to extract just a single architecture.
            auto binary = llvm::object::MachOUniversalBinary::create(mb.get()->getMemBufferRef());
            if (!binary)
            {
                error = "Couldn't read Mach-O universal binary:";
                handleAllErrors(binary.takeError(), [&error](const ErrorInfoBase &ei) {
                    error += " " + ei.message();
                });
                return;
            }
 
            for (auto &o : binary.get()->objects())
            {
                if (o.getArchFlagName() == arch)
                    bitcodeBuffer = MemoryBufferRef(mb.get()->getMemBufferRef().getBuffer().slice(o.getOffset(), o.getOffset() + o.getSize()), "");
 
                availableArchs.insert(o.getArchFlagName());
            }
 
            if (!bitcodeBuffer.getBufferSize())
            {
                error = "The Mach-O universal binary doesn't have an \"" + arch + "\" slice";
                return;
            }
        }
 
        auto wrappedModule = llvm::parseBitcodeFile(bitcodeBuffer, *globalLLVMContext);
        if (!wrappedModule)
        {
            error = "Couldn't parse bitcode file:";
            handleAllErrors(wrappedModule.takeError(), [&error](const ErrorInfoBase &ei) {
                error += " " + ei.message();
            });
            return;
        }
 
        module = wrappedModule.get().release();
 
        if (moduleArch.empty())
            moduleArch = getTargetArch(module->getTargetTriple());
 
        if (availableArchs.empty())
            availableArchs.insert(moduleArch);
 
        if (moduleArch != arch)
        {
            error = "The module's CPU architecture \"" + moduleArch + "\" doesn't match the compiler's CPU architecture \"" + arch + "\"";
            delete module;
            module = nullptr;
            return;
        }
    });
    return module;
}
 
bool VuoCompiler::writeModuleToBitcode(Module *module, string outputPath)
{
    string str;
    raw_string_ostream verifyOut(str);
    if (llvm::verifyModule(*module, &verifyOut))
    {
        VUserLog("Error: Module verification failed:\n%s", verifyOut.str().c_str());
        return true;
    }
 
    // Ensure the module gets output in the bitcode wrapper format instead of raw bitcode.
    if (module->getTargetTriple().empty())
        setTargetForModule(module, getProcessTarget());
 
    std::error_code err;
    raw_fd_ostream out(outputPath.c_str(), err, sys::fs::F_None);
    if (err)
    {
        VUserLog("Error: Couldn't open file '%s' for writing: %s", outputPath.c_str(), err.message().c_str());
        return true;
    }
    llvm::WriteBitcodeToFile(module, out);
 
    return false;
}
 
void VuoCompiler::setTargetForModule(Module *module, string targetTriple)
{
    // Replace the OS version in targetTriple to avoid warnings about linking modules of different target triples.
    llvm::Triple triple(targetTriple);
    if (triple.isMacOSX())
        triple.setOSName("macosx10.10.0");
 
    module->setTargetTriple(triple.str());
 
    string error;
    auto target = TargetRegistry::lookupTarget(module->getTargetTriple(), error);
    if (!target)
    {
        VUserLog("Error: Couldn't look up target: %s", error.c_str());
        return;
    }
 
    auto targetMachine = target->createTargetMachine(module->getTargetTriple(), "", "", TargetOptions(), Optional<Reloc::Model>());
    if (!targetMachine)
    {
        VUserLog("Error: Couldn't create targetMachine.");
        return;
    }
 
    module->setDataLayout(targetMachine->createDataLayout());
 
    delete targetMachine;
}
 
string VuoCompiler::getTargetArch(string target)
{
    auto hyphen = target.find('-');
    if (hyphen == string::npos)
        return "";
 
    return target.substr(0, hyphen);
}
 
string VuoCompiler::getProcessTarget(void)
{
    // llvm::sys::getProcessTriple() returns `LLVM_HOST_TRIPLE`,
    // which is always `x86_64-*` since we built LLVM on x86_64.
    // Instead, use llvm::sys::getDefaultTargetTriple()
    // which _actually_ returns the current process's target.
    llvm::Triple triple(llvm::sys::getDefaultTargetTriple());
 
    // Replace darwin with macosx, e.g. x86_64-apple-darwin18.7.0 -> x86_64-apple-macosx10.14.6
    if (triple.isMacOSX())
    {
        unsigned int major, minor, micro;
        if (triple.getMacOSXVersion(major, minor, micro))
        {
            ostringstream osVersion;
            osVersion << "macosx" << major << "." << minor << "." << micro;
            triple.setOSName(osVersion.str());
        }
    }
 
    return triple.str();
}
 
void VuoCompiler::destroyModule(VuoCompilerModule *module)
{
    Module *llvmModule = module->getModule();
 
    // In C++ the return value of a cast may not be the same pointer as the cast arg.
    // Because of this, VuoModule::getPseudoBase() returns a different value than VuoNodeClass::getBase().
    // Calling delete on VuoModule::getPseudoBase() gives a malloc error: "pointer being freed was not allocated".
    // So call it on VuoNodeClass::getBase(). Same idea for VuoType.
 
    VuoNodeClass *baseNodeClass = NULL;
    VuoType *baseType = NULL;
    VuoModule *baseModule = NULL;
    VuoCompilerNodeClass *nodeClass = dynamic_cast<VuoCompilerNodeClass *>(module);
    if (nodeClass)
    {
        baseNodeClass = dynamic_cast<VuoNodeClass *>(nodeClass->getBase());
 
        if (dynamic_cast<VuoCompilerSpecializedNodeClass *>(module))
            module = NULL;
    }
    else
    {
        VuoCompilerType *type = dynamic_cast<VuoCompilerType *>(module);
        if (type)
            baseType = dynamic_cast<VuoType *>(type->getBase());
        else
            baseModule = module->getPseudoBase();
    }
 
    delete module;
    delete baseNodeClass;
    delete baseType;
    delete baseModule;
    destroyLlvmModule(llvmModule);
}
 
void VuoCompiler::destroyLlvmModule(Module *module)
{
    dispatch_sync(llvmQueue, ^{
                      delete module;
                  });
}
 
VuoNode * VuoCompiler::createNode(VuoCompilerNodeClass *nodeClass, string title, double x, double y)
{
    VuoCompilerNodeClass *nodeClassForNode = VuoCompilerSpecializedNodeClass::getNodeClassForNode(nodeClass, this);
    if (nodeClassForNode)
        return nodeClassForNode->newNode(title, x, y);
 
    return nullptr;
}
 
VuoNode * VuoCompiler::createNode(VuoCompilerNodeClass *nodeClass, VuoNode *nodeToCopyMetadataFrom)
{
    VuoCompilerNodeClass *nodeClassForNode = VuoCompilerSpecializedNodeClass::getNodeClassForNode(nodeClass, this);
    if (nodeClassForNode)
        return nodeClassForNode->newNode(nodeToCopyMetadataFrom);
 
    return nullptr;
}
 
VuoNode * VuoCompiler::createPublishedInputNode(vector<VuoPublishedPort *> publishedInputPorts)
{
    string nodeClassName = VuoCompilerPublishedInputNodeClass::buildNodeClassName(publishedInputPorts);
    return createPublishedNode(nodeClassName, publishedInputPorts);
}
 
VuoNode * VuoCompiler::createPublishedOutputNode(vector<VuoPublishedPort *> publishedOutputPorts)
{
    string nodeClassName = VuoCompilerPublishedOutputNodeClass::buildNodeClassName(publishedOutputPorts);
    return createPublishedNode(nodeClassName, publishedOutputPorts);
}
 
VuoNode * VuoCompiler::createPublishedNode(const string &nodeClassName, const vector<VuoPublishedPort *> &publishedPorts)
{
    VuoCompilerNodeClass *nodeClass = getNodeClass(nodeClassName);
    VuoNode *node = createNode(nodeClass);
 
    // Set the generic port types on the node to match those on the published ports set by VuoCompilerComposition::updateGenericPortTypes().
    VuoCompilerPublishedInputNodeClass *inputNodeClass = dynamic_cast<VuoCompilerPublishedInputNodeClass *>(nodeClass);
    VuoCompilerPublishedOutputNodeClass *outputNodeClass = dynamic_cast<VuoCompilerPublishedOutputNodeClass *>(nodeClass);
    for (size_t i = 0; i < publishedPorts.size(); ++i)
    {
        VuoType *publishedPortType = static_cast<VuoCompilerPort *>(publishedPorts[i]->getCompiler())->getDataVuoType();
        if (! dynamic_cast<VuoGenericType *>(publishedPortType))
            continue;
 
        set<VuoPort *> nodePorts;
        if (inputNodeClass)
        {
            VuoPort *inputPort = node->getInputPorts().at( inputNodeClass->getInputPortIndexForPublishedInputPort(i) );
            nodePorts.insert(inputPort);
 
            VuoPort *outputPort = node->getOutputPorts().at( inputNodeClass->getOutputPortIndexForPublishedInputPort(i) );
            nodePorts.insert(outputPort);
        }
        else
        {
            VuoPort *inputPort = node->getInputPorts().at( outputNodeClass->getInputPortIndexForPublishedOutputPort(i) );
            nodePorts.insert(inputPort);
        }
 
        for (VuoPort *port : nodePorts)
        {
            VuoCompilerPort *compilerPort = static_cast<VuoCompilerPort *>(port->getCompiler());
            compilerPort->setDataVuoType(publishedPortType);
        }
    }
 
    reifyGenericPortTypes(node);
 
    return node;
}
 
void VuoCompiler::installNodeClassAtCompositionLocalScope(const string &sourcePath)
{
    dispatch_sync(environmentQueue, ^{
        if (environments.size() >= 5)
            environments.at(3).at(0)->addExpatriateSourceFile(sourcePath);
    });
}
 
void VuoCompiler::uninstallNodeClassAtCompositionLocalScope(const string &sourcePath)
{
    dispatch_sync(environmentQueue, ^{
        if (environments.size() >= 5)
        {
            environments.at(3).at(0)->removeExpatriateSourceFile(sourcePath);
 
            set<string> sourcesRemoved;
            sourcesRemoved.insert(getModuleKeyForPath(sourcePath));
            loadModulesAndSources(set<string>(), set<string>(), set<string>(), set<string>(), set<string>(), sourcesRemoved,
                                  false, false, environments.at(3).at(0), nullptr, nullptr, "");
        }
    });
}
 
void VuoCompiler::overrideInstalledNodeClass(const string &sourcePath, const string &sourceCode)
{
    string sourcePathCopy = sourcePath;
    string sourceCodeCopy = sourceCode;
 
    dispatch_async(environmentQueue, ^{
        string nodeClassName = getModuleKeyForPath(sourcePathCopy);
        ModuleInfo *sourceInfo = NULL;
 
        for (const vector<Environment *> &envs : environments)
        {
            for (Environment *env : envs)
            {
                ModuleInfo *potentialSourceInfo = env->listSourceFile(nodeClassName);
                if (potentialSourceInfo && VuoFileUtilities::arePathsEqual(potentialSourceInfo->getFile()->path(), sourcePathCopy))
                {
                    sourceInfo = potentialSourceInfo;
                    break;
                }
            }
        }
 
        if (! sourceInfo)
            return;
 
        bool shouldRecompileSourcesIfUnchanged;
        if (! sourceCodeCopy.empty())
        {
            sourceInfo->setSourceCode(sourceCodeCopy);
            sourceInfo->setSourceCodeOverridden(true);
 
            shouldRecompileSourcesIfUnchanged = false;
        }
        else
        {
            sourceInfo->revertSourceCode();
            sourceInfo->setSourceCodeOverridden(false);
 
            shouldRecompileSourcesIfUnchanged = true;
        }
        sourceInfo->setAttempted(false);
        sourceInfo->setLastModifiedToNow();
 
        set<string> sourcesModified;
        sourcesModified.insert(nodeClassName);
 
        loadModulesAndSources(set<string>(), set<string>(), set<string>(), set<string>(), sourcesModified, set<string>(),
                              false, shouldRecompileSourcesIfUnchanged, nullptr, nullptr, nullptr, "");
    });
}
 
void VuoCompiler::revertOverriddenNodeClass(const string &sourcePath)
{
    overrideInstalledNodeClass(sourcePath, "");
}
 
VuoCompilerNodeClass * VuoCompiler::getNodeClass(const string &nodeClassName)
{
    // For performance, don't bother searching if it's obviously not a node class.
 
    if (VuoStringUtilities::endsWith(nodeClassName, ".framework"))
        return NULL;
 
    // Attempt to load the node class (if it hasn't already been loaded).
 
    set<string> nodeClassNameSet;
    nodeClassNameSet.insert(nodeClassName);
    loadModulesIfNeeded(nodeClassNameSet);
 
    // If the node class has been loaded, return it.
 
    __block VuoCompilerNodeClass *nodeClass = NULL;
    void (^envGetNodeClass)(Environment *) = ^void (Environment *env) {
        VuoCompilerNodeClass *result = env->getNodeClass(nodeClassName);
        if (result)
            nodeClass = result;
    };
    applyToAllEnvironments(envGetNodeClass);
    return nodeClass;
}
 
map<string, VuoCompilerNodeClass *> VuoCompiler::getNodeClasses()
{
    loadModulesIfNeeded();
 
    __block map<string, VuoCompilerNodeClass *> nodeClasses;
    void (^envGetNodeClasses)(Environment *) = ^void (Environment *env) {
        map<string, VuoCompilerNodeClass *> result = env->getNodeClasses();
        nodeClasses.insert(result.begin(), result.end());
    };
    applyToInstalledEnvironments(envGetNodeClasses);
    return nodeClasses;
}
 
VuoCompilerType * VuoCompiler::getType(const string &typeName)
{
    set<string> typeNameSet;
    typeNameSet.insert(typeName);
    loadModulesIfNeeded(typeNameSet);
 
    __block VuoCompilerType *type = NULL;
    void (^envGetType)(Environment *) = ^void (Environment *env) {
        VuoCompilerType *result = env->getType(typeName);
        if (result)
            type = result;
    };
    applyToInstalledEnvironments(envGetType);
 
    if (! type && VuoGenericType::isGenericTypeName(typeName))
    {
        VuoCompilerType * (^compilerGetType)(string) = ^VuoCompilerType * (string moduleKey) {
            return getType(moduleKey);
        };
 
        VuoGenericType *genericType = new VuoGenericType(typeName, vector<string>());
        type = VuoCompilerGenericType::newGenericType(genericType, compilerGetType);
    }
 
    return type;
}
 
map<string, VuoCompilerType *> VuoCompiler::getTypes()
{
    loadModulesIfNeeded();
 
    __block map<string, VuoCompilerType *> types;
    void (^envGetTypes)(Environment *) = ^void (Environment *env) {
        map<string, VuoCompilerType *> result = env->getTypes();
        types.insert(result.begin(), result.end());
    };
    applyToInstalledEnvironments(envGetTypes);
    return types;
}
 
VuoCompilerModule *VuoCompiler::getLibraryModule(const string &libraryModuleName)
{
    set<string> libraryNameSet;
    libraryNameSet.insert(libraryModuleName);
    loadModulesIfNeeded(libraryNameSet);
 
    __block VuoCompilerModule *module = nullptr;
    void (^envGetLibraryModule)(Environment *) = ^void (Environment *env) {
        VuoCompilerModule *result = env->getLibraryModule(libraryModuleName);
        if (result)
            module = result;
    };
    applyToInstalledEnvironments(envGetLibraryModule);
 
    return module;
}
 
map<string, VuoCompilerModule *> VuoCompiler::getLibraryModules()
{
    loadModulesIfNeeded();
 
    __block map<string, VuoCompilerModule *> libraryModules;
    void (^envGetLibraryModules)(Environment *) = ^void (Environment *env) {
        map<string, VuoCompilerModule *> result = env->getLibraryModules();
        libraryModules.insert(result.begin(), result.end());
    };
    applyToInstalledEnvironments(envGetLibraryModules);
    return libraryModules;
}
 
map<string, VuoNodeSet *> VuoCompiler::getNodeSets()
{
    loadModulesIfNeeded();
 
    __block map<string, VuoNodeSet *> nodeSets;
    void (^envGetNodeSets)(Environment *) = ^void (Environment *env) {
        map<string, VuoNodeSet *> result = env->getNodeSets();
        nodeSets.insert(result.begin(), result.end());
    };
    applyToInstalledEnvironments(envGetNodeSets);
    return nodeSets;
}
 
VuoNodeSet * VuoCompiler::getNodeSetForName(const string &name)
{
    loadModulesIfNeeded();
 
    __block VuoNodeSet *nodeSet = NULL;
    void (^envFindNodeSet)(Environment *) = ^void (Environment *env) {
        VuoNodeSet *result = env->findNodeSet(name);
        if (result)
            nodeSet = result;
    };
    applyToInstalledEnvironments(envFindNodeSet);
    return nodeSet;
}
 
VuoCompilerModule * VuoCompiler::getModule(const string &moduleKey)
{
    __block VuoCompilerModule *module = NULL;
    void (^envFindModule)(Environment *) = ^void (Environment *env) {
        VuoCompilerModule *result = env->findModule(moduleKey);
        if (result)
            module = result;
    };
    applyToAllEnvironments(envFindModule);
    return module;
}
 
void VuoCompiler::listNodeClasses(const string &format)
{
    map<string, VuoCompilerNodeClass *> nodeClasses = getNodeClasses();
    for (map<string, VuoCompilerNodeClass *>::const_iterator i = nodeClasses.begin(); i != nodeClasses.end(); ++i)
    {
        VuoCompilerNodeClass *nodeClass = i->second;
        if (format == "")
        {
            printf("%s\n", nodeClass->getBase()->getClassName().c_str());
        }
        else if (format == "path")
        {
            // TODO: If "path", prints the absolute path of each node class, one per line.
        }
        else if (format == "dot")
        {
            VuoCompilerNode *node = nodeClass->newNode()->getCompiler();
 
            printf("%s\n", nodeClass->getDoxygenDocumentation().c_str());
            printf("%s\n\n", node->getGraphvizDeclaration().c_str());
 
            delete node;
        }
    }
}
 
vector<string> VuoCompiler::getRunPathSearchPaths(Environment *narrowestScope)
{
    vector<string> rPaths;
    for (size_t i = 0; i < environments.size(); ++i)
    {
        if (i == 0)
        {
            string vuoFrameworkPath = getVuoFrameworkPath();
            if (! vuoFrameworkPath.empty())
                rPaths.push_back(vuoFrameworkPath + "/..");
        }
        else if (i == 1)
            rPaths.push_back(VuoFileUtilities::getSystemModulesPath());
        else if (i == 2)
            rPaths.push_back(VuoFileUtilities::getUserModulesPath());
        else if (i == 3)
        {
            string localModulesPath = getCompositionLocalModulesPath();
            if (! localModulesPath.empty())
                rPaths.push_back(localModulesPath);
        }
 
        if (std::find(environments[i].begin(), environments[i].end(), narrowestScope) != environments[i].end())
            break;
    }
 
    std::reverse(rPaths.begin(), rPaths.end());
    return rPaths;
}
 
vector<string> VuoCompiler::getCoreVuoDependencies(void)
{
    vector<string> dependencies;
 
    dependencies.push_back("VuoHeap");
    dependencies.push_back("VuoApp");
 
    dependencies.push_back("zmq");
    dependencies.push_back("json-c");
    dependencies.push_back("objc");
    dependencies.push_back("c");
    dependencies.push_back("AppKit.framework");
 
#ifdef COVERAGE
    dependencies.push_back(LLVM_ROOT "/lib/libprofile_rt.dylib");
#endif
    return dependencies;
}
 
string VuoCompiler::getRuntimeMainDependency(void)
{
    return "VuoRuntimeMain.o";
}
 
string VuoCompiler::getRuntimeDependency(void)
{
    return "VuoRuntime.o";
}
 
string VuoCompiler::getVuoFrameworkPath(void)
{
    if (! vuoFrameworkInProgressPath.empty())
        return vuoFrameworkInProgressPath;
 
    return VuoFileUtilities::getVuoFrameworkPath();
}
 
string VuoCompiler::getClangPath(void)
{
    return clangPath;
}
 
string VuoCompiler::getModuleKeyForPath(string path)
{
    // Start with the file name without extension.
    string dir, moduleKey, ext;
    VuoFileUtilities::splitPath(path, dir, moduleKey, ext);
 
    if (VuoFileUtilities::isIsfSourceExtension(ext))
    {
        vector<string> nodeClassNameParts = VuoStringUtilities::split(moduleKey, '.');
 
        // Remove repeated file extensions.
        while (nodeClassNameParts.size() > 1 && nodeClassNameParts.back() == ext)
            nodeClassNameParts.pop_back();
 
        // Convert each part to lowerCamelCase.
        for (string &part : nodeClassNameParts)
            part = VuoStringUtilities::convertToCamelCase(part, false, true, false);
 
        // If the node class name has only one part, add a prefix.
        if (nodeClassNameParts.size() == 1)
            nodeClassNameParts.insert(nodeClassNameParts.begin(), "isf");
 
        moduleKey = VuoStringUtilities::join(nodeClassNameParts, '.');
    }
 
    return moduleKey;
}
 
bool VuoCompiler::isCompositionLocalModule(string moduleKey)
{
    __block bool isLocal = false;
 
    dispatch_sync(environmentQueue, ^{
        if (environments.size() >= 5)
            isLocal = environments.at(3).at(0)->findModule(moduleKey);
    });
 
    return isLocal;
}
 
string VuoCompiler::getCompositionLocalModulesPath(void)
{
    return lastCompositionBaseDir.empty() ? "" : lastCompositionBaseDir + "/Modules";
}
 
string VuoCompiler::getCompositionLocalPath(void)
{
    return lastCompositionBaseDir;
}
 
void VuoCompiler::addModuleSearchPath(string path)
{
    dispatch_sync(environmentQueue, ^{
        environments.back().at(0)->addModuleSearchPath(path);
        environments.back().at(0)->addLibrarySearchPath(path);
    });
}
 
void VuoCompiler::addHeaderSearchPath(const string &path)
{
    dispatch_sync(environmentQueue, ^{
        environments.back().at(0)->addHeaderSearchPath(path);
    });
}
 
void VuoCompiler::addLibrarySearchPath(const string &path)
{
    dispatch_sync(environmentQueue, ^{
        environments.back().at(0)->addLibrarySearchPath(path);
    });
}
 
void VuoCompiler::addFrameworkSearchPath(const string &path)
{
    dispatch_sync(environmentQueue, ^{
        environments.back().at(0)->addFrameworkSearchPath(path);
    });
}
 
void VuoCompiler::setVerbose(bool isVerbose)
{
    this->isVerbose = isVerbose;
}
 
void VuoCompiler::setShouldPotentiallyShowSplashWindow(bool potentiallyShow)
{
#if VUO_PRO
    if (VuoPro::getProAccess())
    {
        _shouldShowSplashWindow = false;
        return;
    }
#endif
 
    _shouldShowSplashWindow = potentiallyShow;
}
 
void VuoCompiler::setDependencyOutput(const string &path)
{
#if VUO_PRO
    _setDependencyOutput(path);
#endif
}
 
bool VuoCompiler::shouldShowSplashWindow()
{
    return _shouldShowSplashWindow;
}
 
void VuoCompiler::setClangPath(const string &clangPath)
{
    this->clangPath = clangPath;
}
 
string VuoCompiler::getCompositionLoaderPath(void)
{
    string vuoFrameworkPath = getVuoFrameworkPath();
    return (vuoFrameworkPath.empty() ?
                VUO_BUILD_DIR "/bin/VuoCompositionLoader.app/Contents/MacOS/VuoCompositionLoader" :
                vuoFrameworkPath + "/Helpers/VuoCompositionLoader.app/Contents/MacOS/VuoCompositionLoader");
}
 
string VuoCompiler::getCompositionStubPath(void)
{
    string vuoFrameworkPath = getVuoFrameworkPath();
    return (vuoFrameworkPath.empty() ?
                VUO_BUILD_DIR "/lib/libVuoCompositionStub.dylib" :
                vuoFrameworkPath + "/Modules/libVuoCompositionStub.dylib");
}
 
string VuoCompiler::getCachePathForComposition(const string compositionDir)
{
    string modifierLetterColon("꞉");
    string cachedModulesName = compositionDir;
    VuoStringUtilities::replaceAll(cachedModulesName, "/", modifierLetterColon);
    return VuoFileUtilities::getCachePath() + "/" + cachedModulesName;
}
 
void VuoCompiler::print(void)
{
    __block vector<string> moduleSearchPaths;
    void (^envGetModuleSearchPaths)(Environment *) = ^void (Environment *env) {
        vector<string> result = env->getModuleSearchPaths();
        moduleSearchPaths.insert(moduleSearchPaths.end(), result.begin(), result.end());
    };
    applyToInstalledEnvironments(envGetModuleSearchPaths);
 
    __block vector<string> headerSearchPaths;
    void (^envGetHeaderSearchPaths)(Environment *) = ^void (Environment *env) {
        vector<string> result = env->getHeaderSearchPaths();
        headerSearchPaths.insert(headerSearchPaths.end(), result.begin(), result.end());
    };
    applyToInstalledEnvironments(envGetHeaderSearchPaths);
 
    __block vector<string> librarySearchPaths;
    void (^envGetLibrarySearchPaths)(Environment *) = ^void (Environment *env) {
        vector<string> result = env->getLibrarySearchPaths();
        librarySearchPaths.insert(librarySearchPaths.end(), result.begin(), result.end());
    };
    applyToInstalledEnvironments(envGetLibrarySearchPaths);
 
    __block vector<string> frameworkSearchPaths;
    void (^envGetFrameworkSearchPaths)(Environment *) = ^void (Environment *env) {
        vector<string> result = env->getFrameworkSearchPaths();
        frameworkSearchPaths.insert(frameworkSearchPaths.end(), result.begin(), result.end());
    };
    applyToInstalledEnvironments(envGetFrameworkSearchPaths);
 
    fprintf(stderr, "Module (node class, type, library) search paths:\n");
    for (vector<string>::iterator i = moduleSearchPaths.begin(); i != moduleSearchPaths.end(); ++i)
        fprintf(stderr, " %s\n", (*i).c_str());
    fprintf(stderr, "Header search paths:\n");
    for (vector<string>::iterator i = headerSearchPaths.begin(); i != headerSearchPaths.end(); ++i)
        fprintf(stderr, " %s\n", (*i).c_str());
    fprintf(stderr, "Other library search paths:\n");
    for (vector<string>::iterator i = librarySearchPaths.begin(); i != librarySearchPaths.end(); ++i)
        fprintf(stderr, " %s\n", (*i).c_str());
    fprintf(stderr, "Other framework search paths:\n");
    for (vector<string>::iterator i = frameworkSearchPaths.begin(); i != frameworkSearchPaths.end(); ++i)
        fprintf(stderr, " %s\n", (*i).c_str());
    fprintf(stderr, "Framework path:\n");
    if (! getVuoFrameworkPath().empty())
        fprintf(stderr, " %s\n", getVuoFrameworkPath().c_str());
    fprintf(stderr, "Clang path:\n");
    if (! getClangPath().empty())
        fprintf(stderr, " %s\n", getClangPath().c_str());
}
 
VuoRunner * VuoCompiler::newSeparateProcessRunnerFromCompositionFile(string compositionFilePath, VuoCompilerIssues *issues)
{
    try
    {
        VuoCompiler compiler(compositionFilePath);
        string directory, file, extension;
        VuoFileUtilities::splitPath(compositionFilePath, directory, file, extension);
        string compiledCompositionPath = VuoFileUtilities::makeTmpFile(file, "bc");
        string linkedCompositionPath = VuoFileUtilities::makeTmpFile(file + "-linked", "");
        compiler.compileComposition(compositionFilePath, compiledCompositionPath, true, issues);
        compiler.linkCompositionToCreateExecutable(compiledCompositionPath, linkedCompositionPath, Optimization_FastBuild);
        remove(compiledCompositionPath.c_str());
        return VuoRunner::newSeparateProcessRunnerFromExecutable(linkedCompositionPath, directory, false, true);
    }
    catch (VuoCompilerException &e)
    {
        if (issues != e.getIssues())
            issues->append(e.getIssues());
        return NULL;
    }
}
 
VuoRunner * VuoCompiler::newSeparateProcessRunnerFromCompositionString(string composition, string processName, string workingDirectory, VuoCompilerIssues *issues)
{
    try
    {
        string compositionPath = (workingDirectory.empty() ? "." : workingDirectory) + "/" + processName + ".vuo";
        VuoCompiler compiler(compositionPath);
        string compiledCompositionPath = VuoFileUtilities::makeTmpFile(processName, "bc");
        string linkedCompositionPath = VuoFileUtilities::makeTmpFile(processName, "");
        compiler.compileCompositionString(composition, compiledCompositionPath, true, issues);
        compiler.linkCompositionToCreateExecutable(compiledCompositionPath, linkedCompositionPath, Optimization_FastBuild);
        remove(compiledCompositionPath.c_str());
        return VuoRunner::newSeparateProcessRunnerFromExecutable(linkedCompositionPath, workingDirectory, false, true);
    }
    catch (VuoCompilerException &e)
    {
        if (issues != e.getIssues())
            issues->append(e.getIssues());
        return NULL;
    }
}
 
VuoRunner * VuoCompiler::newCurrentProcessRunnerFromCompositionFile(string compositionFilePath, VuoCompilerIssues *issues)
{
    try
    {
        VuoCompiler compiler(compositionFilePath);
        string directory, file, extension;
        VuoFileUtilities::splitPath(compositionFilePath, directory, file, extension);
        string compiledCompositionPath = VuoFileUtilities::makeTmpFile(file, "bc");
        compiler.compileComposition(compositionFilePath, compiledCompositionPath, true, issues);
        string linkedCompositionPath = VuoFileUtilities::makeTmpFile(file, "dylib");
        compiler.linkCompositionToCreateDynamicLibrary(compiledCompositionPath, linkedCompositionPath, Optimization_FastBuild);
        remove(compiledCompositionPath.c_str());
        return VuoRunner::newCurrentProcessRunnerFromDynamicLibrary(linkedCompositionPath, directory, true);
    }
    catch (VuoCompilerException &e)
    {
        if (issues != e.getIssues())
            issues->append(e.getIssues());
        return NULL;
    }
}
 
VuoRunner * VuoCompiler::newCurrentProcessRunnerFromCompositionString(string composition, string workingDirectory, VuoCompilerIssues *issues)
{
    try
    {
        string compositionPath = (workingDirectory.empty() ? "." : workingDirectory) + "/UntitledComposition.vuo";
        VuoCompiler compiler(compositionPath);
        string compiledCompositionPath = VuoFileUtilities::makeTmpFile("VuoRunnerComposition", "bc");
        compiler.compileCompositionString(composition, compiledCompositionPath, true, issues);
        string linkedCompositionPath = VuoFileUtilities::makeTmpFile("VuoRunnerComposition", "dylib");
        compiler.linkCompositionToCreateDynamicLibrary(compiledCompositionPath, linkedCompositionPath, Optimization_FastBuild);
        remove(compiledCompositionPath.c_str());
        return VuoRunner::newCurrentProcessRunnerFromDynamicLibrary(linkedCompositionPath, workingDirectory, true);
    }
    catch (VuoCompilerException &e)
    {
        if (issues != e.getIssues())
            issues->append(e.getIssues());
        return NULL;
    }
}
 
VuoCompilerDelegate::VuoCompilerDelegate(void)
{
    pendingDataQueue = dispatch_queue_create("org.vuo.compiler.delegate.pending", 0);
}
 
void VuoCompilerDelegate::loadedModulesCompleted(void)
{
    LoadedModulesData *data = dequeueData();
    data->release();
}
 
void VuoCompilerDelegate::enqueueData(LoadedModulesData *data)
{
    dispatch_sync(pendingDataQueue, ^{
                      pendingData.push_back(data);
                  });
}
 
VuoCompilerDelegate::LoadedModulesData * VuoCompilerDelegate::dequeueData(void)
{
    __block LoadedModulesData *ret;
    dispatch_sync(pendingDataQueue, ^{
                      ret = pendingData.front();
                      pendingData.pop_front();
                  });
    return ret;
}
 
VuoCompilerDelegate::LoadedModulesData::LoadedModulesData(const set< pair<VuoCompilerModule *, VuoCompilerModule *> > &modulesModified,
                                                          const set<VuoCompilerModule *> &modulesRemoved, VuoCompilerIssues *issues)
{
    referenceCountQueue = dispatch_queue_create("org.vuo.compiler.delegate.reference", 0);
    referenceCount = 0;
 
    this->modulesModified = modulesModified;
    this->modulesRemoved = modulesRemoved;
    this->issues = issues;
}
 
VuoCompilerDelegate::LoadedModulesData::~LoadedModulesData(void)
{
    delete issues;
 
    for (set< pair<VuoCompilerModule *, VuoCompilerModule *> >::iterator i = modulesModified.begin(); i != modulesModified.end(); ++i)
        VuoCompiler::destroyModule((*i).first);
 
    for (set<VuoCompilerModule *>::iterator i = modulesRemoved.begin(); i != modulesRemoved.end(); ++i)
        VuoCompiler::destroyModule(*i);
}
 
void VuoCompilerDelegate::LoadedModulesData::retain(void)
{
    dispatch_sync(referenceCountQueue, ^{
                      ++referenceCount;
                  });
}
 
void VuoCompilerDelegate::LoadedModulesData::release(void)
{
    dispatch_sync(referenceCountQueue, ^{
                      --referenceCount;
                      if (referenceCount == 0) {
                          delete this;
                      }
                  });
}