[ThinLTO] Refactor ODR resolution and internalization (NFC)
Move the now index-based ODR resolution and internalization routines out
of ThinLTOCodeGenerator.cpp and into either LTO.cpp (index-based
analysis) or FunctionImport.cpp (index-driven optimizations).
This is to enable usage by other linkers.
llvm-svn: 270698
diff --git a/llvm/lib/Transforms/IPO/FunctionImport.cpp b/llvm/lib/Transforms/IPO/FunctionImport.cpp
index a089f3c..3e4cbf5 100644
--- a/llvm/lib/Transforms/IPO/FunctionImport.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionImport.cpp
@@ -16,16 +16,19 @@
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringSet.h"
+#include "llvm/ADT/Triple.h"
#include "llvm/IR/AutoUpgrade.h"
#include "llvm/IR/DiagnosticPrinter.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Module.h"
#include "llvm/IRReader/IRReader.h"
#include "llvm/Linker/Linker.h"
+#include "llvm/Object/IRObjectFile.h"
#include "llvm/Object/ModuleSummaryIndexObjectFile.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/SourceMgr.h"
+#include "llvm/Transforms/IPO/Internalize.h"
#include "llvm/Transforms/Utils/FunctionImportUtils.h"
#define DEBUG_TYPE "function-import"
@@ -460,6 +463,80 @@
return std::error_code();
}
+/// Fixup WeakForLinker linkages in \p TheModule based on summary analysis.
+void llvm::thinLTOResolveWeakForLinkerModule(
+ Module &TheModule, const GVSummaryMapTy &DefinedGlobals) {
+ auto updateLinkage = [&](GlobalValue &GV) {
+ if (!GlobalValue::isWeakForLinker(GV.getLinkage()))
+ return;
+ // See if the global summary analysis computed a new resolved linkage.
+ const auto &GS = DefinedGlobals.find(GV.getGUID());
+ if (GS == DefinedGlobals.end())
+ return;
+ auto NewLinkage = GS->second->linkage();
+ if (NewLinkage == GV.getLinkage())
+ return;
+ DEBUG(dbgs() << "ODR fixing up linkage for `" << GV.getName() << "` from "
+ << GV.getLinkage() << " to " << NewLinkage << "\n");
+ GV.setLinkage(NewLinkage);
+ };
+
+ // Process functions and global now
+ for (auto &GV : TheModule)
+ updateLinkage(GV);
+ for (auto &GV : TheModule.globals())
+ updateLinkage(GV);
+ for (auto &GV : TheModule.aliases())
+ updateLinkage(GV);
+}
+
+/// Run internalization on \p TheModule based on symmary analysis.
+void llvm::thinLTOInternalizeModule(Module &TheModule,
+ const GVSummaryMapTy &DefinedGlobals) {
+ // Parse inline ASM and collect the list of symbols that are not defined in
+ // the current module.
+ StringSet<> AsmUndefinedRefs;
+ object::IRObjectFile::CollectAsmUndefinedRefs(
+ Triple(TheModule.getTargetTriple()), TheModule.getModuleInlineAsm(),
+ [&AsmUndefinedRefs](StringRef Name, object::BasicSymbolRef::Flags Flags) {
+ if (Flags & object::BasicSymbolRef::SF_Undefined)
+ AsmUndefinedRefs.insert(Name);
+ });
+
+ // Declare a callback for the internalize pass that will ask for every
+ // candidate GlobalValue if it can be internalized or not.
+ auto MustPreserveGV = [&](const GlobalValue &GV) -> bool {
+ // Can't be internalized if referenced in inline asm.
+ if (AsmUndefinedRefs.count(GV.getName()))
+ return true;
+
+ // Lookup the linkage recorded in the summaries during global analysis.
+ const auto &GS = DefinedGlobals.find(GV.getGUID());
+ GlobalValue::LinkageTypes Linkage;
+ if (GS == DefinedGlobals.end()) {
+ // Must have been promoted (possibly conservatively). Find original
+ // name so that we can access the correct summary and see if it can
+ // be internalized again.
+ // FIXME: Eventually we should control promotion instead of promoting
+ // and internalizing again.
+ StringRef OrigName =
+ ModuleSummaryIndex::getOriginalNameBeforePromote(GV.getName());
+ std::string OrigId = GlobalValue::getGlobalIdentifier(
+ OrigName, GlobalValue::InternalLinkage,
+ TheModule.getSourceFileName());
+ const auto &GS = DefinedGlobals.find(GlobalValue::getGUID(OrigId));
+ assert(GS != DefinedGlobals.end());
+ Linkage = GS->second->linkage();
+ } else
+ Linkage = GS->second->linkage();
+ return !GlobalValue::isLocalLinkage(Linkage);
+ };
+
+ // FIXME: See if we can just internalize directly here via linkage changes
+ // based on the index, rather than invoking internalizeModule.
+ llvm::internalizeModule(TheModule, MustPreserveGV);
+}
+
// Automatically import functions in Module \p DestModule based on the summaries
// index.
//