[LTO] Switch Module to std::unique_ptr<>

[davide]

Summary

In preparation for the parallel LTO codegen work (see splitCodeGen in gold-plugin). If it turns out we don't want parallel LTO for the ELF linker, I'll revert this one.

[ruiu]

ELF/LTO.h

43

blah -> ld-temp.o

*Combined.get() can be *Combined?

Does Combined owns the newly created llvm::Module?

[davide]

ELF/LTO.h

43

I think so.

[ruiu]

LGTM

ELF/LTO.h

43

Need a space before {}. (Or run clang-format-diff.)

[ruiu]

ELF/LTO.h

43

Maybe it's because you have an extra ; at end of the line?

ELF/LTO.h

 class BitcodeFile;
 class InputFile;
 
 class BitcodeCompiler {
 public:
   void add(BitcodeFile &F);
   std::unique_ptr<InputFile> compile();
 
+  BitcodeCompiler()
+      : Combined(new llvm::Module("ld-temp.o", Context)), Mover(*Combined){};
+
 private:
   llvm::TargetMachine *getTargetMachine();
 
   llvm::LLVMContext Context;
-  llvm::Module Combined{"ld-temp.o", Context};
-  llvm::IRMover Mover{Combined};
+  std::unique_ptr<llvm::Module> Combined;
+  llvm::IRMover Mover;
   SmallString<0> OwningData;
   std::unique_ptr<MemoryBuffer> MB;
   llvm::StringSet<> InternalizedSyms;
 };
 }
 }
 
 #endif

ELF/LTO.cpp

assert(!GV.hasLocalLinkage() &&
          "Trying to internalize a symbol with local linkage!");
   GV.setLinkage(GlobalValue::InternalLinkage);
 }
 
 // Merge all the bitcode files we have seen, codegen the result
 // and return the resulting ObjectFile.
 std::unique_ptr<InputFile> BitcodeCompiler::compile() {
   for (const auto &Name : InternalizedSyms) {
-    GlobalValue *GV = Combined.getNamedValue(Name.first());
+    GlobalValue *GV = Combined->getNamedValue(Name.first());
     assert(GV);
     internalize(*GV);
   }
 
   if (Config->SaveTemps)
-    saveBCFile(Combined, ".lto.bc");
+    saveBCFile(*Combined, ".lto.bc");
 
   std::unique_ptr<TargetMachine> TM(getTargetMachine());
-  runLTOPasses(Combined, *TM);
+  runLTOPasses(*Combined, *TM);
 
   raw_svector_ostream OS(OwningData);
   legacy::PassManager CodeGenPasses;
   if (TM->addPassesToEmitFile(CodeGenPasses, OS,
                               TargetMachine::CGFT_ObjectFile))
     fatal("failed to setup codegen");
-  CodeGenPasses.run(Combined);
+  CodeGenPasses.run(*Combined);
   MB = MemoryBuffer::getMemBuffer(OwningData,
                                   "LLD-INTERNAL-combined-lto-object", false);
   if (Config->SaveTemps)
     saveLtoObjectFile(MB->getBuffer());
   return createObjectFile(*MB);
 }
 
 TargetMachine *BitcodeCompiler::getTargetMachine() {
-  StringRef TripleStr = Combined.getTargetTriple();
+  StringRef TripleStr = Combined->getTargetTriple();
   std::string Msg;
   const Target *T = TargetRegistry::lookupTarget(TripleStr, Msg);
   if (!T)
     fatal("target not found: " + Msg);
   TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
   Reloc::Model R = Config->Pic ? Reloc::PIC_ : Reloc::Static;
   return T->createTargetMachine(TripleStr, "", "", Options, R);
 }