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[Dependency Scanner] Use Clang scanner's module name query API instead of creating a dummy file #60807

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Sep 12, 2022
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[Dependency Scanner] Use Clang scanner's module name query API instead of creating a dummy file #60807

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75 changes: 10 additions & 65 deletions lib/ClangImporter/ClangModuleDependencyScanner.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -29,12 +29,6 @@ using namespace clang::tooling;
using namespace clang::tooling::dependencies;

class swift::ClangModuleDependenciesCacheImpl {
/// Cache the names of the files used for the "import hack" to compute module
/// dependencies.
/// FIXME: This should go away once Clang's dependency scanning library
/// can scan by module name.
llvm::StringMap<std::string> importHackFileCache;

public:
/// Set containing all of the Clang modules that have already been seen.
llvm::StringSet<> alreadySeen;
Expand All @@ -44,44 +38,11 @@ class swift::ClangModuleDependenciesCacheImpl {
DependencyScanningTool tool;

ClangModuleDependenciesCacheImpl()
: importHackFileCache(), service(ScanningMode::DependencyDirectivesScan,
ScanningOutputFormat::Full,
clang::CASOptions(), nullptr, nullptr),
: service(ScanningMode::DependencyDirectivesScan,
ScanningOutputFormat::Full, clang::CASOptions(), nullptr, nullptr),
tool(service) {}
~ClangModuleDependenciesCacheImpl();

/// Retrieve the name of the file used for the "import hack" that is
/// used to scan the dependencies of a Clang module.
llvm::ErrorOr<StringRef> getImportHackFile(StringRef moduleName);
};

ClangModuleDependenciesCacheImpl::~ClangModuleDependenciesCacheImpl() {
if (!importHackFileCache.empty()) {
for (auto& it: importHackFileCache) {
llvm::sys::fs::remove(it.second);
}
}
}

llvm::ErrorOr<StringRef> ClangModuleDependenciesCacheImpl::getImportHackFile(StringRef moduleName) {
auto cacheIt = importHackFileCache.find(moduleName.str());
if (cacheIt != importHackFileCache.end())
return cacheIt->second;

// Create a temporary file.
int resultFD;
SmallString<128> resultPath;
if (auto error = llvm::sys::fs::createTemporaryFile(
"import-hack-" + moduleName.str(), "c", resultFD, resultPath))
return error;

llvm::raw_fd_ostream out(resultFD, /*shouldClose=*/true);
out << "#pragma clang module import " << moduleName.str() << ";\n";
llvm::sys::RemoveFileOnSignal(resultPath);
importHackFileCache.insert(std::make_pair(moduleName, resultPath.str().str()));
return importHackFileCache[moduleName];
}

// Add search paths.
// Note: This is handled differently for the Clang importer itself, which
// adds search paths to Clang's data structures rather than to its
Expand All @@ -103,7 +64,7 @@ static void addSearchPathInvocationArguments(
/// Create the command line for Clang dependency scanning.
static std::vector<std::string> getClangDepScanningInvocationArguments(
ASTContext &ctx,
StringRef sourceFileName) {
Optional<StringRef> sourceFileName = None) {
std::vector<std::string> commandLineArgs;

// Form the basic command line.
Expand All @@ -116,7 +77,10 @@ static std::vector<std::string> getClangDepScanningInvocationArguments(
commandLineArgs.begin(), commandLineArgs.end(),
"<swift-imported-modules>");
assert(sourceFilePos != commandLineArgs.end());
*sourceFilePos = sourceFileName.str();
if (sourceFileName.hasValue())
*sourceFilePos = sourceFileName->str();
else
commandLineArgs.erase(sourceFilePos);

// HACK! Drop the -fmodule-format= argument and the one that
// precedes it.
Expand All @@ -140,18 +104,6 @@ static std::vector<std::string> getClangDepScanningInvocationArguments(
*syntaxOnlyPos = "-c";
}

// HACK: Stolen from ClangScanDeps.cpp
commandLineArgs.push_back("-o");
commandLineArgs.push_back("/dev/null");
commandLineArgs.push_back("-M");
commandLineArgs.push_back("-MT");
commandLineArgs.push_back("import-hack.o");
commandLineArgs.push_back("-Xclang");
commandLineArgs.push_back("-Eonly");
commandLineArgs.push_back("-Xclang");
commandLineArgs.push_back("-sys-header-deps");
commandLineArgs.push_back("-Wno-error");

return commandLineArgs;
}

Expand Down Expand Up @@ -323,16 +275,9 @@ Optional<ModuleDependencies> ClangImporter::getModuleDependencies(
// Retrieve or create the shared state.
auto clangImpl = getOrCreateClangImpl(cache);

// HACK! Replace the module import buffer name with the source file hack.
auto importHackFile = clangImpl->getImportHackFile(moduleName);
if (!importHackFile) {
// FIXME: Emit a diagnostic here.
return None;
}

// Determine the command-line arguments for dependency scanning.
std::vector<std::string> commandLineArgs =
getClangDepScanningInvocationArguments(ctx, *importHackFile);
getClangDepScanningInvocationArguments(ctx);
// The Swift compiler does not have a concept of a working directory.
// It is instead handled by the Swift driver by resolving relative paths
// according to the driver's notion of a working directory. On the other hand,
Expand All @@ -354,7 +299,7 @@ Optional<ModuleDependencies> ClangImporter::getModuleDependencies(
}

auto clangDependencies = clangImpl->tool.getFullDependencies(
commandLineArgs, workingDir, clangImpl->alreadySeen);
commandLineArgs, workingDir, clangImpl->alreadySeen, moduleName);
if (!clangDependencies) {
auto errorStr = toString(clangDependencies.takeError());
// We ignore the "module 'foo' not found" error, the Swift dependency
Expand Down Expand Up @@ -407,7 +352,7 @@ bool ClangImporter::addBridgingHeaderDependencies(

// Determine the command-line arguments for dependency scanning.
std::vector<std::string> commandLineArgs =
getClangDepScanningInvocationArguments(ctx, bridgingHeader);
getClangDepScanningInvocationArguments(ctx, StringRef(bridgingHeader));
std::string workingDir =
ctx.SourceMgr.getFileSystem()->getCurrentWorkingDirectory().get();

Expand Down