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[clangd] [Modules] Support Reusable Modules Builder #106683

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Nov 12, 2024
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[clangd] [Modules] Support Reusable Modules Builder #106683

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15aa6af
[clangd] [Modules] Support Reusable Modules Builder
ChuanqiXu9 Aug 30, 2024
4ed7bf5
Remove unique builder
ChuanqiXu9 Oct 31, 2024
dcdd18a
Update
ChuanqiXu9 Nov 4, 2024
370b01f
Address comments
ChuanqiXu9 Nov 6, 2024
4e0f1e3
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ChuanqiXu9 Nov 12, 2024
821dc8d
address comments
ChuanqiXu9 Nov 12, 2024
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fmt
ChuanqiXu9 Nov 12, 2024
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242 changes: 170 additions & 72 deletions clang-tools-extra/clangd/ModulesBuilder.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,7 @@
#include "clang/Frontend/FrontendActions.h"
#include "clang/Serialization/ASTReader.h"
#include "clang/Serialization/InMemoryModuleCache.h"
#include "llvm/ADT/ScopeExit.h"

namespace clang {
namespace clangd {
Expand Down Expand Up @@ -192,33 +193,27 @@ bool IsModuleFilesUpToDate(
});
}

// StandalonePrerequisiteModules - stands for PrerequisiteModules for which all
// ReusablePrerequisiteModules - stands for PrerequisiteModules for which all
// the required modules are built successfully. All the module files
// are owned by the StandalonePrerequisiteModules class.
//
// Any of the built module files won't be shared with other instances of the
// class. So that we can avoid worrying thread safety.
//
// We don't need to worry about duplicated module names here since the standard
// guarantees the module names should be unique to a program.
class StandalonePrerequisiteModules : public PrerequisiteModules {
// are owned by the modules builder.
class ReusablePrerequisiteModules : public PrerequisiteModules {
public:
StandalonePrerequisiteModules() = default;
ReusablePrerequisiteModules() = default;

StandalonePrerequisiteModules(const StandalonePrerequisiteModules &) = delete;
StandalonePrerequisiteModules
operator=(const StandalonePrerequisiteModules &) = delete;
StandalonePrerequisiteModules(StandalonePrerequisiteModules &&) = delete;
StandalonePrerequisiteModules
operator=(StandalonePrerequisiteModules &&) = delete;
ReusablePrerequisiteModules(const ReusablePrerequisiteModules &) = delete;
ReusablePrerequisiteModules
operator=(const ReusablePrerequisiteModules &) = delete;
ReusablePrerequisiteModules(ReusablePrerequisiteModules &&) = delete;
ReusablePrerequisiteModules
operator=(ReusablePrerequisiteModules &&) = delete;

~StandalonePrerequisiteModules() override = default;
~ReusablePrerequisiteModules() override = default;

void adjustHeaderSearchOptions(HeaderSearchOptions &Options) const override {
// Appending all built module files.
for (auto &RequiredModule : RequiredModules)
Options.PrebuiltModuleFiles.insert_or_assign(
RequiredModule.ModuleName, RequiredModule.ModuleFilePath);
RequiredModule->ModuleName, RequiredModule->ModuleFilePath);
}

bool canReuse(const CompilerInvocation &CI,
Expand All @@ -228,54 +223,30 @@ class StandalonePrerequisiteModules : public PrerequisiteModules {
return BuiltModuleNames.contains(ModuleName);
}

void addModuleFile(llvm::StringRef ModuleName,
llvm::StringRef ModuleFilePath) {
RequiredModules.emplace_back(ModuleName, ModuleFilePath);
BuiltModuleNames.insert(ModuleName);
void addModuleFile(std::shared_ptr<ModuleFile> BMI) {
BuiltModuleNames.insert(BMI->ModuleName);
RequiredModules.emplace_back(std::move(BMI));
}

private:
llvm::SmallVector<ModuleFile, 8> RequiredModules;
mutable llvm::SmallVector<std::shared_ptr<ModuleFile>, 8> RequiredModules;
// A helper class to speedup the query if a module is built.
llvm::StringSet<> BuiltModuleNames;
};

// Build a module file for module with `ModuleName`. The information of built
// module file are stored in \param BuiltModuleFiles.
llvm::Error buildModuleFile(llvm::StringRef ModuleName,
const GlobalCompilationDatabase &CDB,
const ThreadsafeFS &TFS, ProjectModules &MDB,
PathRef ModuleFilesPrefix,
StandalonePrerequisiteModules &BuiltModuleFiles) {
if (BuiltModuleFiles.isModuleUnitBuilt(ModuleName))
return llvm::Error::success();

PathRef ModuleUnitFileName = MDB.getSourceForModuleName(ModuleName);
// It is possible that we're meeting third party modules (modules whose
// source are not in the project. e.g, the std module may be a third-party
// module for most projects) or something wrong with the implementation of
// ProjectModules.
// FIXME: How should we treat third party modules here? If we want to ignore
// third party modules, we should return true instead of false here.
// Currently we simply bail out.
if (ModuleUnitFileName.empty())
return llvm::createStringError("Failed to get the primary source");

/// Build a module file for module with `ModuleName`. The information of built
/// module file are stored in \param BuiltModuleFiles.
llvm::Expected<ModuleFile>
buildModuleFile(llvm::StringRef ModuleName, PathRef ModuleUnitFileName,
const GlobalCompilationDatabase &CDB, const ThreadsafeFS &TFS,
PathRef ModuleFilesPrefix,
const ReusablePrerequisiteModules &BuiltModuleFiles) {
// Try cheap operation earlier to boil-out cheaply if there are problems.
auto Cmd = CDB.getCompileCommand(ModuleUnitFileName);
if (!Cmd)
return llvm::createStringError(
llvm::formatv("No compile command for {0}", ModuleUnitFileName));

for (auto &RequiredModuleName : MDB.getRequiredModules(ModuleUnitFileName)) {
// Return early if there are errors building the module file.
if (llvm::Error Err = buildModuleFile(RequiredModuleName, CDB, TFS, MDB,
ModuleFilesPrefix, BuiltModuleFiles))
return llvm::createStringError(
llvm::formatv("Failed to build dependency {0}: {1}",
RequiredModuleName, llvm::toString(std::move(Err))));
}

Cmd->Output = getModuleFilePath(ModuleName, ModuleFilesPrefix);

ParseInputs Inputs;
Expand Down Expand Up @@ -316,36 +287,169 @@ llvm::Error buildModuleFile(llvm::StringRef ModuleName,
if (Clang->getDiagnostics().hasErrorOccurred())
return llvm::createStringError("Compilation failed");

BuiltModuleFiles.addModuleFile(ModuleName, Inputs.CompileCommand.Output);
return llvm::Error::success();
return ModuleFile{ModuleName, Inputs.CompileCommand.Output};
}

bool ReusablePrerequisiteModules::canReuse(
const CompilerInvocation &CI,
llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS) const {
if (RequiredModules.empty())
return true;

SmallVector<StringRef> BMIPaths;
for (auto &MF : RequiredModules)
BMIPaths.push_back(MF->ModuleFilePath);
return IsModuleFilesUpToDate(BMIPaths, *this, VFS);
}
} // namespace

class ModulesBuilder::ModuleFileCache {
public:
ModuleFileCache(const GlobalCompilationDatabase &CDB) : CDB(CDB) {}

llvm::Error
getOrBuildModuleFile(StringRef ModuleName, const ThreadsafeFS &TFS,
ProjectModules &MDB,
ReusablePrerequisiteModules &RequiredModules);
const GlobalCompilationDatabase &getCDB() const { return CDB; }

private:
std::shared_ptr<ModuleFile>
getValidModuleFile(StringRef ModuleName, ProjectModules &MDB,
const ThreadsafeFS &TFS,
PrerequisiteModules &BuiltModuleFiles);

/// This should only be called by getValidModuleFile. This is unlocked version
/// of getValidModuleFile. The function is extracted to avoid dead locks when
/// recursing.
std::shared_ptr<ModuleFile>
isValidModuleFileUnlocked(StringRef ModuleName, ProjectModules &MDB,
const ThreadsafeFS &TFS,
PrerequisiteModules &BuiltModuleFiles);

const GlobalCompilationDatabase &CDB;

llvm::StringMap<std::shared_ptr<ModuleFile>> ModuleFiles;
// Mutex to guard accesses to ModuleFiles.
std::mutex ModuleFilesMutex;
};

std::shared_ptr<ModuleFile>
ModulesBuilder::ModuleFileCache::isValidModuleFileUnlocked(
StringRef ModuleName, ProjectModules &MDB, const ThreadsafeFS &TFS,
PrerequisiteModules &BuiltModuleFiles) {
auto Iter = ModuleFiles.find(ModuleName);
if (Iter != ModuleFiles.end()) {
if (!IsModuleFileUpToDate(Iter->second->ModuleFilePath, BuiltModuleFiles,
TFS.view(std::nullopt))) {
log("Found not-up-date module file {0} for module {1} in cache",
Iter->second->ModuleFilePath, ModuleName);
ModuleFiles.erase(Iter);
return nullptr;
}

if (llvm::any_of(
MDB.getRequiredModules(MDB.getSourceForModuleName(ModuleName)),
[&MDB, &TFS, &BuiltModuleFiles, this](auto &&RequiredModuleName) {
return !isValidModuleFileUnlocked(RequiredModuleName, MDB, TFS,
BuiltModuleFiles);
})) {
ModuleFiles.erase(Iter);
return nullptr;
}

return Iter->second;
}

log("Don't find {0} in cache", ModuleName);

return nullptr;
}

std::shared_ptr<ModuleFile> ModulesBuilder::ModuleFileCache::getValidModuleFile(
StringRef ModuleName, ProjectModules &MDB, const ThreadsafeFS &TFS,
PrerequisiteModules &BuiltModuleFiles) {
std::lock_guard<std::mutex> _(ModuleFilesMutex);

return isValidModuleFileUnlocked(ModuleName, MDB, TFS, BuiltModuleFiles);
}

llvm::Error ModulesBuilder::ModuleFileCache::getOrBuildModuleFile(
StringRef ModuleName, const ThreadsafeFS &TFS, ProjectModules &MDB,
ReusablePrerequisiteModules &BuiltModuleFiles) {
if (BuiltModuleFiles.isModuleUnitBuilt(ModuleName))
return llvm::Error::success();

PathRef ModuleUnitFileName = MDB.getSourceForModuleName(ModuleName);
/// It is possible that we're meeting third party modules (modules whose
/// source are not in the project. e.g, the std module may be a third-party
/// module for most project) or something wrong with the implementation of
/// ProjectModules.
/// FIXME: How should we treat third party modules here? If we want to ignore
/// third party modules, we should return true instead of false here.
/// Currently we simply bail out.
if (ModuleUnitFileName.empty())
return llvm::createStringError(
llvm::formatv("Don't get the module unit for module {0}", ModuleName));

for (auto &RequiredModuleName : MDB.getRequiredModules(ModuleUnitFileName))
// Return early if there are errors building the module file.
if (!getOrBuildModuleFile(RequiredModuleName, TFS, MDB, BuiltModuleFiles))
return llvm::createStringError(
llvm::formatv("Failed to build module {0}", RequiredModuleName));

if (std::shared_ptr<ModuleFile> Cached =
getValidModuleFile(ModuleName, MDB, TFS, BuiltModuleFiles)) {
log("Reusing module {0} from {1}", ModuleName, Cached->ModuleFilePath);
BuiltModuleFiles.addModuleFile(Cached);
return llvm::Error::success();
}

log("Building module {0}", ModuleName);

llvm::SmallString<256> ModuleFilesPrefix =
getUniqueModuleFilesPath(ModuleUnitFileName);

llvm::Expected<ModuleFile> MF =
buildModuleFile(ModuleName, ModuleUnitFileName, CDB, TFS,
ModuleFilesPrefix, BuiltModuleFiles);
if (llvm::Error Err = MF.takeError())
return Err;

log("Built module {0} to {1}", ModuleName, MF->ModuleFilePath);

std::lock_guard<std::mutex> __(ModuleFilesMutex);
auto BuiltModuleFile = std::make_shared<ModuleFile>(std::move(*MF));
ModuleFiles.insert_or_assign(ModuleName, BuiltModuleFile);
BuiltModuleFiles.addModuleFile(std::move(BuiltModuleFile));

return llvm::Error::success();
}
std::unique_ptr<PrerequisiteModules>
ModulesBuilder::buildPrerequisiteModulesFor(PathRef File,
const ThreadsafeFS &TFS) const {
std::unique_ptr<ProjectModules> MDB = CDB.getProjectModules(File);
const ThreadsafeFS &TFS) {
std::unique_ptr<ProjectModules> MDB =
MFCache->getCDB().getProjectModules(File);
if (!MDB) {
elog("Failed to get Project Modules information for {0}", File);
return std::make_unique<FailedPrerequisiteModules>();
}

std::vector<std::string> RequiredModuleNames = MDB->getRequiredModules(File);
if (RequiredModuleNames.empty())
return std::make_unique<StandalonePrerequisiteModules>();
return std::make_unique<ReusablePrerequisiteModules>();

llvm::SmallString<256> ModuleFilesPrefix = getUniqueModuleFilesPath(File);

log("Trying to build required modules for {0} in {1}", File,
ModuleFilesPrefix);
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this is no longer the case, you can drop this (and the following log after the build)

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Done


auto RequiredModules = std::make_unique<StandalonePrerequisiteModules>();
auto RequiredModules = std::make_unique<ReusablePrerequisiteModules>();

for (llvm::StringRef RequiredModuleName : RequiredModuleNames) {
// Return early if there is any error.
if (llvm::Error Err =
buildModuleFile(RequiredModuleName, CDB, TFS, *MDB.get(),
ModuleFilesPrefix, *RequiredModules.get())) {
if (llvm::Error Err = MFCache->getOrBuildModuleFile(
RequiredModuleName, TFS, *MDB.get(), *RequiredModules.get())) {
elog("Failed to build module {0}; due to {1}", RequiredModuleName,
toString(std::move(Err)));
return std::make_unique<FailedPrerequisiteModules>();
Expand All @@ -357,17 +461,11 @@ ModulesBuilder::buildPrerequisiteModulesFor(PathRef File,
return std::move(RequiredModules);
}

bool StandalonePrerequisiteModules::canReuse(
const CompilerInvocation &CI,
llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS) const {
if (RequiredModules.empty())
return true;

SmallVector<StringRef> BMIPaths;
for (auto &MF : RequiredModules)
BMIPaths.push_back(MF.ModuleFilePath);
return IsModuleFilesUpToDate(BMIPaths, *this, VFS);
ModulesBuilder::ModulesBuilder(const GlobalCompilationDatabase &CDB) {
MFCache = std::make_unique<ModuleFileCache>(CDB);
}

ModulesBuilder::~ModulesBuilder() {}

} // namespace clangd
} // namespace clang
8 changes: 5 additions & 3 deletions clang-tools-extra/clangd/ModulesBuilder.h
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Original file line number Diff line number Diff line change
Expand Up @@ -85,7 +85,8 @@ class PrerequisiteModules {
/// different versions and different source files.
class ModulesBuilder {
public:
ModulesBuilder(const GlobalCompilationDatabase &CDB) : CDB(CDB) {}
ModulesBuilder(const GlobalCompilationDatabase &CDB);
~ModulesBuilder();

ModulesBuilder(const ModulesBuilder &) = delete;
ModulesBuilder(ModulesBuilder &&) = delete;
Expand All @@ -94,10 +95,11 @@ class ModulesBuilder {
ModulesBuilder &operator=(ModulesBuilder &&) = delete;

std::unique_ptr<PrerequisiteModules>
buildPrerequisiteModulesFor(PathRef File, const ThreadsafeFS &TFS) const;
buildPrerequisiteModulesFor(PathRef File, const ThreadsafeFS &TFS);

private:
const GlobalCompilationDatabase &CDB;
class ModuleFileCache;
std::unique_ptr<ModuleFileCache> MFCache;
};

} // namespace clangd
Expand Down
36 changes: 36 additions & 0 deletions clang-tools-extra/clangd/unittests/PrerequisiteModulesTest.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -482,6 +482,42 @@ void func() {
EXPECT_EQ(Result.signatures[0].parameters[0].labelString, "int a");
}

TEST_F(PrerequisiteModulesTests, ReusablePrerequisiteModulesTest) {
MockDirectoryCompilationDatabase CDB(TestDir, FS);

CDB.addFile("M.cppm", R"cpp(
export module M;
export int M = 43;
)cpp");
CDB.addFile("A.cppm", R"cpp(
export module A;
import M;
export int A = 43 + M;
)cpp");
CDB.addFile("B.cppm", R"cpp(
export module B;
import M;
export int B = 44 + M;
)cpp");

ModulesBuilder Builder(CDB);

auto AInfo = Builder.buildPrerequisiteModulesFor(getFullPath("A.cppm"), FS);
EXPECT_TRUE(AInfo);
auto BInfo = Builder.buildPrerequisiteModulesFor(getFullPath("B.cppm"), FS);
EXPECT_TRUE(BInfo);
HeaderSearchOptions HSOptsA(TestDir);
HeaderSearchOptions HSOptsB(TestDir);
AInfo->adjustHeaderSearchOptions(HSOptsA);
BInfo->adjustHeaderSearchOptions(HSOptsB);

EXPECT_FALSE(HSOptsA.PrebuiltModuleFiles.empty());
EXPECT_FALSE(HSOptsB.PrebuiltModuleFiles.empty());

// Check that we're reusing the module files.
EXPECT_EQ(HSOptsA.PrebuiltModuleFiles, HSOptsB.PrebuiltModuleFiles);
}

} // namespace
} // namespace clang::clangd

Expand Down
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