llvm-project/llvm/lib/LTO/LTO.cpp

644 lines
24 KiB
C++

//===-LTO.cpp - LLVM Link Time Optimizer ----------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements functions and classes used to support LTO.
//
//===----------------------------------------------------------------------===//
#include "llvm/LTO/LTO.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/Bitcode/ReaderWriter.h"
#include "llvm/CodeGen/Analysis.h"
#include "llvm/IR/AutoUpgrade.h"
#include "llvm/IR/DiagnosticPrinter.h"
#include "llvm/IR/LegacyPassManager.h"
#include "llvm/LTO/LTOBackend.h"
#include "llvm/Linker/IRMover.h"
#include "llvm/Object/ModuleSummaryIndexObjectFile.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/ThreadPool.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/IPO/PassManagerBuilder.h"
#include "llvm/Transforms/Utils/SplitModule.h"
#include <set>
using namespace llvm;
using namespace lto;
using namespace object;
// Simple helper to load a module from bitcode
std::unique_ptr<Module>
llvm::loadModuleFromBuffer(const MemoryBufferRef &Buffer, LLVMContext &Context,
bool Lazy) {
SMDiagnostic Err;
ErrorOr<std::unique_ptr<Module>> ModuleOrErr(nullptr);
if (Lazy) {
ModuleOrErr =
getLazyBitcodeModule(MemoryBuffer::getMemBuffer(Buffer, false), Context,
/* ShouldLazyLoadMetadata */ Lazy);
} else {
ModuleOrErr = parseBitcodeFile(Buffer, Context);
}
if (std::error_code EC = ModuleOrErr.getError()) {
Err = SMDiagnostic(Buffer.getBufferIdentifier(), SourceMgr::DK_Error,
EC.message());
Err.print("ThinLTO", errs());
report_fatal_error("Can't load module, abort.");
}
return std::move(ModuleOrErr.get());
}
static void thinLTOResolveWeakForLinkerGUID(
GlobalValueSummaryList &GVSummaryList, GlobalValue::GUID GUID,
DenseSet<GlobalValueSummary *> &GlobalInvolvedWithAlias,
function_ref<bool(GlobalValue::GUID, const GlobalValueSummary *)>
isPrevailing,
function_ref<void(StringRef, GlobalValue::GUID, GlobalValue::LinkageTypes)>
recordNewLinkage) {
for (auto &S : GVSummaryList) {
if (GlobalInvolvedWithAlias.count(S.get()))
continue;
GlobalValue::LinkageTypes OriginalLinkage = S->linkage();
if (!GlobalValue::isWeakForLinker(OriginalLinkage))
continue;
// We need to emit only one of these. The prevailing module will keep it,
// but turned into a weak, while the others will drop it when possible.
if (isPrevailing(GUID, S.get())) {
if (GlobalValue::isLinkOnceLinkage(OriginalLinkage))
S->setLinkage(GlobalValue::getWeakLinkage(
GlobalValue::isLinkOnceODRLinkage(OriginalLinkage)));
}
// Alias can't be turned into available_externally.
else if (!isa<AliasSummary>(S.get()) &&
(GlobalValue::isLinkOnceODRLinkage(OriginalLinkage) ||
GlobalValue::isWeakODRLinkage(OriginalLinkage)))
S->setLinkage(GlobalValue::AvailableExternallyLinkage);
if (S->linkage() != OriginalLinkage)
recordNewLinkage(S->modulePath(), GUID, S->linkage());
}
}
// Resolve Weak and LinkOnce values in the \p Index.
//
// We'd like to drop these functions if they are no longer referenced in the
// current module. However there is a chance that another module is still
// referencing them because of the import. We make sure we always emit at least
// one copy.
void llvm::thinLTOResolveWeakForLinkerInIndex(
ModuleSummaryIndex &Index,
function_ref<bool(GlobalValue::GUID, const GlobalValueSummary *)>
isPrevailing,
function_ref<void(StringRef, GlobalValue::GUID, GlobalValue::LinkageTypes)>
recordNewLinkage) {
// We won't optimize the globals that are referenced by an alias for now
// Ideally we should turn the alias into a global and duplicate the definition
// when needed.
DenseSet<GlobalValueSummary *> GlobalInvolvedWithAlias;
for (auto &I : Index)
for (auto &S : I.second)
if (auto AS = dyn_cast<AliasSummary>(S.get()))
GlobalInvolvedWithAlias.insert(&AS->getAliasee());
for (auto &I : Index)
thinLTOResolveWeakForLinkerGUID(I.second, I.first, GlobalInvolvedWithAlias,
isPrevailing, recordNewLinkage);
}
static void thinLTOInternalizeAndPromoteGUID(
GlobalValueSummaryList &GVSummaryList, GlobalValue::GUID GUID,
function_ref<bool(StringRef, GlobalValue::GUID)> isExported) {
for (auto &S : GVSummaryList) {
if (isExported(S->modulePath(), GUID)) {
if (GlobalValue::isLocalLinkage(S->linkage()))
S->setLinkage(GlobalValue::ExternalLinkage);
} else if (!GlobalValue::isLocalLinkage(S->linkage()))
S->setLinkage(GlobalValue::InternalLinkage);
}
}
// Update the linkages in the given \p Index to mark exported values
// as external and non-exported values as internal.
void llvm::thinLTOInternalizeAndPromoteInIndex(
ModuleSummaryIndex &Index,
function_ref<bool(StringRef, GlobalValue::GUID)> isExported) {
for (auto &I : Index)
thinLTOInternalizeAndPromoteGUID(I.second, I.first, isExported);
}
Expected<std::unique_ptr<InputFile>> InputFile::create(MemoryBufferRef Object) {
std::unique_ptr<InputFile> File(new InputFile);
std::string Msg;
auto DiagHandler = [](const DiagnosticInfo &DI, void *MsgP) {
auto *Msg = reinterpret_cast<std::string *>(MsgP);
raw_string_ostream OS(*Msg);
DiagnosticPrinterRawOStream DP(OS);
DI.print(DP);
};
File->Ctx.setDiagnosticHandler(DiagHandler, static_cast<void *>(&Msg));
ErrorOr<std::unique_ptr<object::IRObjectFile>> IRObj =
IRObjectFile::create(Object, File->Ctx);
if (!Msg.empty())
return make_error<StringError>(Msg, inconvertibleErrorCode());
if (!IRObj)
return errorCodeToError(IRObj.getError());
File->Obj = std::move(*IRObj);
File->Ctx.setDiagnosticHandler(nullptr, nullptr);
return std::move(File);
}
LTO::RegularLTOState::RegularLTOState(unsigned ParallelCodeGenParallelismLevel,
Config &Conf)
: ParallelCodeGenParallelismLevel(ParallelCodeGenParallelismLevel),
Ctx(Conf), CombinedModule(llvm::make_unique<Module>("ld-temp.o", Ctx)),
Mover(*CombinedModule) {}
LTO::ThinLTOState::ThinLTOState(ThinBackend Backend) : Backend(Backend) {
if (!Backend)
this->Backend = createInProcessThinBackend(thread::hardware_concurrency());
}
LTO::LTO(Config Conf, ThinBackend Backend,
unsigned ParallelCodeGenParallelismLevel)
: Conf(std::move(Conf)),
RegularLTO(ParallelCodeGenParallelismLevel, this->Conf),
ThinLTO(std::move(Backend)) {}
// Add the given symbol to the GlobalResolutions map, and resolve its partition.
void LTO::addSymbolToGlobalRes(IRObjectFile *Obj,
SmallPtrSet<GlobalValue *, 8> &Used,
const InputFile::Symbol &Sym,
SymbolResolution Res, unsigned Partition) {
GlobalValue *GV = Obj->getSymbolGV(Sym.I->getRawDataRefImpl());
auto &GlobalRes = GlobalResolutions[Sym.getName()];
if (GV) {
GlobalRes.UnnamedAddr &= GV->hasGlobalUnnamedAddr();
if (Res.Prevailing)
GlobalRes.IRName = GV->getName();
}
if (Res.VisibleToRegularObj || (GV && Used.count(GV)) ||
(GlobalRes.Partition != GlobalResolution::Unknown &&
GlobalRes.Partition != Partition))
GlobalRes.Partition = GlobalResolution::External;
else
GlobalRes.Partition = Partition;
}
void LTO::writeToResolutionFile(InputFile *Input,
ArrayRef<SymbolResolution> Res) {
StringRef Path = Input->Obj->getMemoryBufferRef().getBufferIdentifier();
*Conf.ResolutionFile << Path << '\n';
auto ResI = Res.begin();
for (const InputFile::Symbol &Sym : Input->symbols()) {
assert(ResI != Res.end());
SymbolResolution Res = *ResI++;
*Conf.ResolutionFile << "-r=" << Path << ',' << Sym.getName() << ',';
if (Res.Prevailing)
*Conf.ResolutionFile << 'p';
if (Res.FinalDefinitionInLinkageUnit)
*Conf.ResolutionFile << 'l';
if (Res.VisibleToRegularObj)
*Conf.ResolutionFile << 'x';
*Conf.ResolutionFile << '\n';
}
assert(ResI == Res.end());
}
Error LTO::add(std::unique_ptr<InputFile> Input,
ArrayRef<SymbolResolution> Res) {
assert(!CalledGetMaxTasks);
if (Conf.ResolutionFile)
writeToResolutionFile(Input.get(), Res);
Module &M = Input->Obj->getModule();
SmallPtrSet<GlobalValue *, 8> Used;
collectUsedGlobalVariables(M, Used, /*CompilerUsed*/ false);
if (!Conf.OverrideTriple.empty())
M.setTargetTriple(Conf.OverrideTriple);
else if (M.getTargetTriple().empty())
M.setTargetTriple(Conf.DefaultTriple);
MemoryBufferRef MBRef = Input->Obj->getMemoryBufferRef();
bool HasThinLTOSummary = hasGlobalValueSummary(MBRef, Conf.DiagHandler);
if (HasThinLTOSummary)
return addThinLTO(std::move(Input), Res);
else
return addRegularLTO(std::move(Input), Res);
}
// Add a regular LTO object to the link.
Error LTO::addRegularLTO(std::unique_ptr<InputFile> Input,
ArrayRef<SymbolResolution> Res) {
RegularLTO.HasModule = true;
ErrorOr<std::unique_ptr<object::IRObjectFile>> ObjOrErr =
IRObjectFile::create(Input->Obj->getMemoryBufferRef(), RegularLTO.Ctx);
if (!ObjOrErr)
return errorCodeToError(ObjOrErr.getError());
std::unique_ptr<object::IRObjectFile> Obj = std::move(*ObjOrErr);
Module &M = Obj->getModule();
M.materializeMetadata();
UpgradeDebugInfo(M);
SmallPtrSet<GlobalValue *, 8> Used;
collectUsedGlobalVariables(M, Used, /*CompilerUsed*/ false);
std::vector<GlobalValue *> Keep;
for (GlobalVariable &GV : M.globals())
if (GV.hasAppendingLinkage())
Keep.push_back(&GV);
auto ResI = Res.begin();
for (const InputFile::Symbol &Sym :
make_range(InputFile::symbol_iterator(Obj->symbol_begin()),
InputFile::symbol_iterator(Obj->symbol_end()))) {
assert(ResI != Res.end());
SymbolResolution Res = *ResI++;
addSymbolToGlobalRes(Obj.get(), Used, Sym, Res, 0);
GlobalValue *GV = Obj->getSymbolGV(Sym.I->getRawDataRefImpl());
if (Res.Prevailing && GV) {
Keep.push_back(GV);
switch (GV->getLinkage()) {
default:
break;
case GlobalValue::LinkOnceAnyLinkage:
GV->setLinkage(GlobalValue::WeakAnyLinkage);
break;
case GlobalValue::LinkOnceODRLinkage:
GV->setLinkage(GlobalValue::WeakODRLinkage);
break;
}
}
// FIXME: use proposed local attribute for FinalDefinitionInLinkageUnit.
}
assert(ResI == Res.end());
return RegularLTO.Mover.move(Obj->takeModule(), Keep,
[](GlobalValue &, IRMover::ValueAdder) {});
}
// Add a ThinLTO object to the link.
Error LTO::addThinLTO(std::unique_ptr<InputFile> Input,
ArrayRef<SymbolResolution> Res) {
Module &M = Input->Obj->getModule();
SmallPtrSet<GlobalValue *, 8> Used;
collectUsedGlobalVariables(M, Used, /*CompilerUsed*/ false);
// We need to initialize the target info for the combined regular LTO module
// in case we have no regular LTO objects. In that case we still need to build
// it as usual because the client may want to add symbol definitions to it.
if (RegularLTO.CombinedModule->getTargetTriple().empty()) {
RegularLTO.CombinedModule->setTargetTriple(M.getTargetTriple());
RegularLTO.CombinedModule->setDataLayout(M.getDataLayout());
}
MemoryBufferRef MBRef = Input->Obj->getMemoryBufferRef();
ErrorOr<std::unique_ptr<object::ModuleSummaryIndexObjectFile>>
SummaryObjOrErr =
object::ModuleSummaryIndexObjectFile::create(MBRef, Conf.DiagHandler);
if (!SummaryObjOrErr)
return errorCodeToError(SummaryObjOrErr.getError());
ThinLTO.CombinedIndex.mergeFrom((*SummaryObjOrErr)->takeIndex(),
ThinLTO.ModuleMap.size());
auto ResI = Res.begin();
for (const InputFile::Symbol &Sym : Input->symbols()) {
assert(ResI != Res.end());
SymbolResolution Res = *ResI++;
addSymbolToGlobalRes(Input->Obj.get(), Used, Sym, Res,
ThinLTO.ModuleMap.size() + 1);
GlobalValue *GV = Input->Obj->getSymbolGV(Sym.I->getRawDataRefImpl());
if (Res.Prevailing && GV)
ThinLTO.PrevailingModuleForGUID[GV->getGUID()] =
MBRef.getBufferIdentifier();
}
assert(ResI == Res.end());
ThinLTO.ModuleMap[MBRef.getBufferIdentifier()] = MBRef;
return Error();
}
unsigned LTO::getMaxTasks() const {
CalledGetMaxTasks = true;
return RegularLTO.ParallelCodeGenParallelismLevel + ThinLTO.ModuleMap.size();
}
Error LTO::run(AddOutputFn AddOutput) {
// Invoke regular LTO if there was a regular LTO module to start with,
// or if there are any hooks that the linker may have used to add
// its own resolved symbols to the combined module.
if (RegularLTO.HasModule || Conf.PreOptModuleHook ||
Conf.PostInternalizeModuleHook || Conf.PostOptModuleHook ||
Conf.PreCodeGenModuleHook)
if (auto E = runRegularLTO(AddOutput))
return E;
return runThinLTO(AddOutput);
}
Error LTO::runRegularLTO(AddOutputFn AddOutput) {
if (Conf.PreOptModuleHook &&
!Conf.PreOptModuleHook(0, *RegularLTO.CombinedModule))
return Error();
for (const auto &R : GlobalResolutions) {
if (R.second.IRName.empty())
continue;
if (R.second.Partition != 0 &&
R.second.Partition != GlobalResolution::External)
continue;
GlobalValue *GV = RegularLTO.CombinedModule->getNamedValue(R.second.IRName);
// Ignore symbols defined in other partitions.
if (!GV || GV->hasLocalLinkage())
continue;
GV->setUnnamedAddr(R.second.UnnamedAddr ? GlobalValue::UnnamedAddr::Global
: GlobalValue::UnnamedAddr::None);
if (R.second.Partition == 0)
GV->setLinkage(GlobalValue::InternalLinkage);
}
if (Conf.PostInternalizeModuleHook &&
!Conf.PostInternalizeModuleHook(0, *RegularLTO.CombinedModule))
return Error();
return backend(Conf, AddOutput, RegularLTO.ParallelCodeGenParallelismLevel,
std::move(RegularLTO.CombinedModule));
}
/// This class defines the interface to the ThinLTO backend.
class lto::ThinBackendProc {
protected:
Config &Conf;
ModuleSummaryIndex &CombinedIndex;
StringMap<GVSummaryMapTy> &ModuleToDefinedGVSummaries;
public:
ThinBackendProc(Config &Conf, ModuleSummaryIndex &CombinedIndex,
StringMap<GVSummaryMapTy> &ModuleToDefinedGVSummaries)
: Conf(Conf), CombinedIndex(CombinedIndex),
ModuleToDefinedGVSummaries(ModuleToDefinedGVSummaries) {}
virtual ~ThinBackendProc() {}
virtual Error start(unsigned Task, MemoryBufferRef MBRef,
const FunctionImporter::ImportMapTy &ImportList,
MapVector<StringRef, MemoryBufferRef> &ModuleMap) = 0;
virtual Error wait() = 0;
};
class InProcessThinBackend : public ThinBackendProc {
ThreadPool BackendThreadPool;
AddOutputFn AddOutput;
Optional<Error> Err;
std::mutex ErrMu;
public:
InProcessThinBackend(Config &Conf, ModuleSummaryIndex &CombinedIndex,
unsigned ThinLTOParallelismLevel,
StringMap<GVSummaryMapTy> &ModuleToDefinedGVSummaries,
AddOutputFn AddOutput)
: ThinBackendProc(Conf, CombinedIndex, ModuleToDefinedGVSummaries),
BackendThreadPool(ThinLTOParallelismLevel),
AddOutput(std::move(AddOutput)) {}
Error
runThinLTOBackendThread(AddOutputFn AddOutput, unsigned Task,
MemoryBufferRef MBRef,
ModuleSummaryIndex &CombinedIndex,
const FunctionImporter::ImportMapTy &ImportList,
const GVSummaryMapTy &DefinedGlobals,
MapVector<StringRef, MemoryBufferRef> &ModuleMap) {
LLVMContext BackendContext;
ErrorOr<std::unique_ptr<Module>> MOrErr =
parseBitcodeFile(MBRef, BackendContext);
assert(MOrErr && "Unable to load module in thread?");
return thinBackend(Conf, Task, AddOutput, **MOrErr, CombinedIndex,
ImportList, DefinedGlobals, ModuleMap);
}
Error start(unsigned Task, MemoryBufferRef MBRef,
const FunctionImporter::ImportMapTy &ImportList,
MapVector<StringRef, MemoryBufferRef> &ModuleMap) override {
StringRef ModulePath = MBRef.getBufferIdentifier();
BackendThreadPool.async(
[=](MemoryBufferRef MBRef, ModuleSummaryIndex &CombinedIndex,
const FunctionImporter::ImportMapTy &ImportList,
GVSummaryMapTy &DefinedGlobals,
MapVector<StringRef, MemoryBufferRef> &ModuleMap) {
Error E =
runThinLTOBackendThread(AddOutput, Task, MBRef, CombinedIndex,
ImportList, DefinedGlobals, ModuleMap);
if (E) {
std::unique_lock<std::mutex> L(ErrMu);
if (Err)
Err = joinErrors(std::move(*Err), std::move(E));
else
Err = std::move(E);
}
},
MBRef, std::ref(CombinedIndex), std::ref(ImportList),
std::ref(ModuleToDefinedGVSummaries[ModulePath]), std::ref(ModuleMap));
return Error();
}
Error wait() override {
BackendThreadPool.wait();
if (Err)
return std::move(*Err);
else
return Error();
}
};
ThinBackend lto::createInProcessThinBackend(unsigned ParallelismLevel) {
return [=](Config &Conf, ModuleSummaryIndex &CombinedIndex,
StringMap<GVSummaryMapTy> &ModuleToDefinedGVSummaries,
AddOutputFn AddOutput) {
return llvm::make_unique<InProcessThinBackend>(
Conf, CombinedIndex, ParallelismLevel, ModuleToDefinedGVSummaries,
AddOutput);
};
}
class WriteIndexesThinBackend : public ThinBackendProc {
std::string OldPrefix, NewPrefix;
bool ShouldEmitImportsFiles;
std::string LinkedObjectsFileName;
std::unique_ptr<llvm::raw_fd_ostream> LinkedObjectsFile;
public:
WriteIndexesThinBackend(Config &Conf, ModuleSummaryIndex &CombinedIndex,
StringMap<GVSummaryMapTy> &ModuleToDefinedGVSummaries,
std::string OldPrefix, std::string NewPrefix,
bool ShouldEmitImportsFiles,
std::string LinkedObjectsFileName)
: ThinBackendProc(Conf, CombinedIndex, ModuleToDefinedGVSummaries),
OldPrefix(OldPrefix), NewPrefix(NewPrefix),
ShouldEmitImportsFiles(ShouldEmitImportsFiles),
LinkedObjectsFileName(LinkedObjectsFileName) {}
/// Given the original \p Path to an output file, replace any path
/// prefix matching \p OldPrefix with \p NewPrefix. Also, create the
/// resulting directory if it does not yet exist.
std::string getThinLTOOutputFile(const std::string &Path,
const std::string &OldPrefix,
const std::string &NewPrefix) {
if (OldPrefix.empty() && NewPrefix.empty())
return Path;
SmallString<128> NewPath(Path);
llvm::sys::path::replace_path_prefix(NewPath, OldPrefix, NewPrefix);
StringRef ParentPath = llvm::sys::path::parent_path(NewPath.str());
if (!ParentPath.empty()) {
// Make sure the new directory exists, creating it if necessary.
if (std::error_code EC = llvm::sys::fs::create_directories(ParentPath))
llvm::errs() << "warning: could not create directory '" << ParentPath
<< "': " << EC.message() << '\n';
}
return NewPath.str();
}
Error start(unsigned Task, MemoryBufferRef MBRef,
const FunctionImporter::ImportMapTy &ImportList,
MapVector<StringRef, MemoryBufferRef> &ModuleMap) override {
StringRef ModulePath = MBRef.getBufferIdentifier();
std::string NewModulePath =
getThinLTOOutputFile(ModulePath, OldPrefix, NewPrefix);
std::error_code EC;
if (!LinkedObjectsFileName.empty()) {
if (!LinkedObjectsFile) {
LinkedObjectsFile = llvm::make_unique<raw_fd_ostream>(
LinkedObjectsFileName, EC, sys::fs::OpenFlags::F_None);
if (EC)
return errorCodeToError(EC);
}
*LinkedObjectsFile << NewModulePath << '\n';
}
std::map<std::string, GVSummaryMapTy> ModuleToSummariesForIndex;
gatherImportedSummariesForModule(ModulePath, ModuleToDefinedGVSummaries,
ImportList, ModuleToSummariesForIndex);
raw_fd_ostream OS(NewModulePath + ".thinlto.bc", EC,
sys::fs::OpenFlags::F_None);
if (EC)
return errorCodeToError(EC);
WriteIndexToFile(CombinedIndex, OS, &ModuleToSummariesForIndex);
if (ShouldEmitImportsFiles)
return errorCodeToError(
EmitImportsFiles(ModulePath, NewModulePath + ".imports", ImportList));
return Error();
}
Error wait() override { return Error(); }
};
ThinBackend lto::createWriteIndexesThinBackend(std::string OldPrefix,
std::string NewPrefix,
bool ShouldEmitImportsFiles,
std::string LinkedObjectsFile) {
return [=](Config &Conf, ModuleSummaryIndex &CombinedIndex,
StringMap<GVSummaryMapTy> &ModuleToDefinedGVSummaries,
AddOutputFn AddOutput) {
return llvm::make_unique<WriteIndexesThinBackend>(
Conf, CombinedIndex, ModuleToDefinedGVSummaries, OldPrefix, NewPrefix,
ShouldEmitImportsFiles, LinkedObjectsFile);
};
}
Error LTO::runThinLTO(AddOutputFn AddOutput) {
if (ThinLTO.ModuleMap.empty())
return Error();
if (Conf.CombinedIndexHook && !Conf.CombinedIndexHook(ThinLTO.CombinedIndex))
return Error();
// Collect for each module the list of function it defines (GUID ->
// Summary).
StringMap<std::map<GlobalValue::GUID, GlobalValueSummary *>>
ModuleToDefinedGVSummaries(ThinLTO.ModuleMap.size());
ThinLTO.CombinedIndex.collectDefinedGVSummariesPerModule(
ModuleToDefinedGVSummaries);
StringMap<FunctionImporter::ImportMapTy> ImportLists(
ThinLTO.ModuleMap.size());
StringMap<FunctionImporter::ExportSetTy> ExportLists(
ThinLTO.ModuleMap.size());
ComputeCrossModuleImport(ThinLTO.CombinedIndex, ModuleToDefinedGVSummaries,
ImportLists, ExportLists);
std::set<GlobalValue::GUID> ExportedGUIDs;
for (auto &Res : GlobalResolutions) {
if (!Res.second.IRName.empty() &&
Res.second.Partition == GlobalResolution::External)
ExportedGUIDs.insert(GlobalValue::getGUID(Res.second.IRName));
}
auto isPrevailing = [&](GlobalValue::GUID GUID, const GlobalValueSummary *S) {
return ThinLTO.PrevailingModuleForGUID[GUID] == S->modulePath();
};
auto isExported = [&](StringRef ModuleIdentifier, GlobalValue::GUID GUID) {
const auto &ExportList = ExportLists.find(ModuleIdentifier);
return (ExportList != ExportLists.end() &&
ExportList->second.count(GUID)) ||
ExportedGUIDs.count(GUID);
};
thinLTOInternalizeAndPromoteInIndex(ThinLTO.CombinedIndex, isExported);
thinLTOResolveWeakForLinkerInIndex(
ThinLTO.CombinedIndex, isPrevailing,
[](StringRef, GlobalValue::GUID, GlobalValue::LinkageTypes) {});
std::unique_ptr<ThinBackendProc> BackendProc = ThinLTO.Backend(
Conf, ThinLTO.CombinedIndex, ModuleToDefinedGVSummaries, AddOutput);
// Partition numbers for ThinLTO jobs start at 1 (see comments for
// GlobalResolution in LTO.h). Task numbers, however, start at
// ParallelCodeGenParallelismLevel, as tasks 0 through
// ParallelCodeGenParallelismLevel-1 are reserved for parallel code generation
// partitions.
unsigned Task = RegularLTO.ParallelCodeGenParallelismLevel;
unsigned Partition = 1;
for (auto &Mod : ThinLTO.ModuleMap) {
if (Error E = BackendProc->start(Task, Mod.second, ImportLists[Mod.first],
ThinLTO.ModuleMap))
return E;
++Task;
++Partition;
}
return BackendProc->wait();
}