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[ThinLTO] Do metadata linking during batch function importing 

Summary:
Since we are currently not doing incremental importing there is
no need to link metadata as a postpass. The module linker will
only link in the imported subroutines due to the functionality
added by r256003.

(Note that the metadata postpass linking functionalitiy is still
used by llvm-link, and may be needed here in the future if a more
incremental strategy is adopted.)

Reviewers: joker.eph

Subscribers: joker.eph, llvm-commits

Differential Revision: http://reviews.llvm.org/D16424

llvm-svn: 258458
This commit is contained in:
Teresa Johnson 2016-01-22 00:15:53 +00:00
parent 68b6d5ac42
commit 6cba37ce75
2 changed files with 7 additions and 29 deletions
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2
llvm/lib/Linker/LinkModules.cpp
View File

@ -137,8 +137,6 @@ public:
// may be exported to another backend compilation.
if (ImportIndex && !FunctionsToImport)
HasExportedFunctions = ImportIndex->hasExportedFunctions(SrcM);
assert((ValIDToTempMDMap || !FunctionsToImport) &&
"Function importing must provide a ValIDToTempMDMap");
}
bool run();

34
llvm/lib/Transforms/IPO/FunctionImport.cpp
View File

@ -41,8 +41,8 @@ static std::unique_ptr<Module> loadFile(const std::string &FileName,
LLVMContext &Context) {
SMDiagnostic Err;
DEBUG(dbgs() << "Loading '" << FileName << "'\n");
// Metadata isn't loaded or linked until after all functions are
// imported, after which it will be materialized and linked.
// Metadata isn't loaded until functions are imported, to minimize
// the memory overhead.
std::unique_ptr<Module> Result =
getLazyIRFileModule(FileName, Err, Context,
/* ShouldLazyLoadMetadata = */ true);
@ -295,9 +295,6 @@ bool FunctionImporter::importFunctions(Module &DestModule) {
ModuleToFunctionsToImportMap, Index, ModuleLoaderCache);
assert(Worklist.empty() && "Worklist hasn't been flushed in GetImportList");
StringMap<std::unique_ptr<DenseMap<unsigned, MDNode *>>>
ModuleToTempMDValsMap;
// Do the actual import of functions now, one Module at a time
for (auto &FunctionsToImportPerModule : ModuleToFunctionsToImportMap) {
// Get the module for the import
@ -307,36 +304,19 @@ bool FunctionImporter::importFunctions(Module &DestModule) {
assert(&DestModule.getContext() == &SrcModule->getContext() &&
"Context mismatch");
// Save the mapping of value ids to temporary metadata created when
// importing this function. If we have already imported from this module,
// add new temporary metadata to the existing mapping.
auto &TempMDVals = ModuleToTempMDValsMap[SrcModule->getModuleIdentifier()];
if (!TempMDVals)
TempMDVals = llvm::make_unique<DenseMap<unsigned, MDNode *>>();
// If modules were created with lazy metadata loading, materialize it
// now, before linking it (otherwise this will be a noop).
SrcModule->materializeMetadata();
UpgradeDebugInfo(*SrcModule);
// Link in the specified functions.
if (TheLinker.linkInModule(std::move(SrcModule), Linker::Flags::None,
&Index, &FunctionsToImport, TempMDVals.get()))
&Index, &FunctionsToImport))
report_fatal_error("Function Import: link error");
ImportedCount += FunctionsToImport.size();
}
// Now link in metadata for all modules from which we imported functions.
for (StringMapEntry<std::unique_ptr<DenseMap<unsigned, MDNode *>>> &SME :
ModuleToTempMDValsMap) {
// Load the specified source module.
auto &SrcModule = ModuleLoaderCache(SME.getKey());
// The modules were created with lazy metadata loading. Materialize it
// now, before linking it.
SrcModule.materializeMetadata();
UpgradeDebugInfo(SrcModule);
// Link in all necessary metadata from this module.
if (TheLinker.linkInMetadata(SrcModule, SME.getValue().get()))
return false;
}
DEBUG(dbgs() << "Imported " << ImportedCount << " functions for Module "
<< DestModule.getModuleIdentifier() << "\n");
return ImportedCount;