LTO: Simplify merged module ownership.

[pcc]

Summary

This change moves LTOCodeGenerator's ownership of the merged module to a
field of type std::unique_ptr<Module>. This helps simplify parts of the code
and clears the way for the module to be consumed by LLVM CodeGen (see D12132
review comments).

This changes the C API semantics (lto_codegen_set_module now destroys its
argument) so I have incremented the API version.

[pcc]

• Restore and deprecate the old lto_codegen_set_module() behaviour until Apple can fix their linker
• Do not destroy the merged module after code generation
• clang-format

[pcc]

• Restore ownership semantics for lto_codegen_set_module
• Remove all remaining references to module via IRLinker

[pcc]

Rename OwnedModule to MergedModule; split out mechanical changes to r245874

llvm/trunk/include/llvm-c/lto.h

  * lto_module_create_in_codegen_context().
  *
  * \since prior to LTO_API_VERSION=3
  */
 extern lto_bool_t
 lto_codegen_add_module(lto_code_gen_t cg, lto_module_t mod);
 
 /**
- * Sets the object module for code generation. This will transfer the ownship of
- * the module to code generator.
+ * Sets the object module for code generation. This will transfer the ownership
+ * of the module to the code generator.
  *
  * \c cg and \c mod must both be in the same context.
  *
  * \since LTO_API_VERSION=13
  */
 extern void
 lto_codegen_set_module(lto_code_gen_t cg, lto_module_t mod);
 

llvm/trunk/include/llvm/LTO/LTOCodeGenerator.h

struct LTOCodeGenerator {
   LTOCodeGenerator();
   LTOCodeGenerator(std::unique_ptr<LLVMContext> Context);
   ~LTOCodeGenerator();
 
   // Merge given module, return true on success.
   bool addModule(struct LTOModule *);
 
   // Set the destination module.
-  void setModule(struct LTOModule *);
+  void setModule(std::unique_ptr<LTOModule> M);
 
   void setTargetOptions(TargetOptions options);
   void setDebugInfo(lto_debug_model);
   void setCodePICModel(Reloc::Model model) { RelocModel = model; }
 
   void setCpu(const char *mCpu) { MCpu = mCpu; }
   void setAttr(const char *mAttr) { MAttr = mAttr; }
   void setOptLevel(unsigned optLevel);
private:
   bool determineTarget(std::string &errMsg);
 
   static void DiagnosticHandler(const DiagnosticInfo &DI, void *Context);
 
   void DiagnosticHandler2(const DiagnosticInfo &DI);
 
   typedef StringMap<uint8_t> StringSet;
 
-  void destroyMergedModule();
   std::unique_ptr<LLVMContext> OwnedContext;
   LLVMContext &Context;
+  std::unique_ptr<Module> MergedModule;
   Linker IRLinker;
   std::unique_ptr<TargetMachine> TargetMach;
   bool EmitDwarfDebugInfo = false;
   bool ScopeRestrictionsDone = false;
   Reloc::Model RelocModel = Reloc::Default;
   StringSet MustPreserveSymbols;
   StringSet AsmUndefinedRefs;
   std::vector<std::string> CodegenOptions;
   std::string FeatureStr;
   std::string MCpu;
   std::string MAttr;
   std::string NativeObjectPath;
   TargetOptions Options;
   CodeGenOpt::Level CGOptLevel = CodeGenOpt::Default;
   unsigned OptLevel = 2;
   lto_diagnostic_handler_t DiagHandler = nullptr;
   void *DiagContext = nullptr;
-  LTOModule *OwnedModule = nullptr;
   bool ShouldInternalize = true;
   bool ShouldEmbedUselists = false;
 };
 }
 #endif

llvm/trunk/include/llvm/LTO/LTOModule.h

public:
 
   const Module &getModule() const {
     return const_cast<LTOModule*>(this)->getModule();
   }
   Module &getModule() {
     return IRFile->getModule();
   }
 
+  std::unique_ptr<Module> takeModule() { return IRFile->takeModule(); }
+
   /// Return the Module's target triple.
   const std::string &getTargetTriple() {
     return getModule().getTargetTriple();
   }
 
   /// Set the Module's target triple.
   void setTargetTriple(StringRef Triple) {
     getModule().setTargetTriple(Triple);

llvm/trunk/lib/LTO/LTOCodeGenerator.cpp

 #ifdef LLVM_VERSION_INFO
   return PACKAGE_NAME " version " PACKAGE_VERSION ", " LLVM_VERSION_INFO;
 #else
   return PACKAGE_NAME " version " PACKAGE_VERSION;
 #endif
 }
 
 LTOCodeGenerator::LTOCodeGenerator()
-    : Context(getGlobalContext()), IRLinker(new Module("ld-temp.o", Context)) {
+    : Context(getGlobalContext()),
+      MergedModule(new Module("ld-temp.o", Context)),
+      IRLinker(MergedModule.get()) {
   initializeLTOPasses();
 }
 
 LTOCodeGenerator::LTOCodeGenerator(std::unique_ptr<LLVMContext> Context)
     : OwnedContext(std::move(Context)), Context(*OwnedContext),
-      IRLinker(new Module("ld-temp.o", *OwnedContext)) {
+      MergedModule(new Module("ld-temp.o", *OwnedContext)),
+      IRLinker(MergedModule.get()) {
   initializeLTOPasses();
 }
 
-void LTOCodeGenerator::destroyMergedModule() {
-  if (OwnedModule) {
-    assert(IRLinker.getModule() == &OwnedModule->getModule() &&
-           "The linker's module should be the same as the owned module");
-    delete OwnedModule;
-    OwnedModule = nullptr;
-  } else if (IRLinker.getModule())
-    IRLinker.deleteModule();
-}
-
-LTOCodeGenerator::~LTOCodeGenerator() {
-  destroyMergedModule();
-}
+LTOCodeGenerator::~LTOCodeGenerator() {}
 
 // Initialize LTO passes. Please keep this funciton in sync with
 // PassManagerBuilder::populateLTOPassManager(), and make sure all LTO
 // passes are initialized.
 void LTOCodeGenerator::initializeLTOPasses() {
   PassRegistry &R = *PassRegistry::getPassRegistry();
 
   initializeInternalizePassPass(R);
bool LTOCodeGenerator::addModule(LTOModule *mod) {
 
   const std::vector<const char*> &undefs = mod->getAsmUndefinedRefs();
   for (int i = 0, e = undefs.size(); i != e; ++i)
     AsmUndefinedRefs[undefs[i]] = 1;
 
   return !ret;
 }
 
-void LTOCodeGenerator::setModule(LTOModule *Mod) {
+void LTOCodeGenerator::setModule(std::unique_ptr<LTOModule> Mod) {
   assert(&Mod->getModule().getContext() == &Context &&
          "Expected module in same context");
 
-  // Delete the old merged module.
-  destroyMergedModule();
   AsmUndefinedRefs.clear();
 
-  OwnedModule = Mod;
-  IRLinker.setModule(&Mod->getModule());
+  MergedModule = Mod->takeModule();
+  IRLinker.setModule(MergedModule.get());
 
   const std::vector<const char*> &Undefs = Mod->getAsmUndefinedRefs();
   for (int I = 0, E = Undefs.size(); I != E; ++I)
     AsmUndefinedRefs[Undefs[I]] = 1;
 }
 
 void LTOCodeGenerator::setTargetOptions(TargetOptions options) {
   Options = options;
bool LTOCodeGenerator::writeMergedModules(const char *path,
   tool_output_file Out(path, EC, sys::fs::F_None);
   if (EC) {
     errMsg = "could not open bitcode file for writing: ";
     errMsg += path;
     return false;
   }
 
   // write bitcode to it
-  WriteBitcodeToFile(IRLinker.getModule(), Out.os(), ShouldEmbedUselists);
+  WriteBitcodeToFile(MergedModule.get(), Out.os(), ShouldEmbedUselists);
   Out.os().close();
 
   if (Out.os().has_error()) {
     errMsg = "could not write bitcode file: ";
     errMsg += path;
     Out.os().clear_error();
     return false;
   }
LTOCodeGenerator::compile(bool disableInline, bool disableGVNLoadPRE,
 
   return compileOptimized(errMsg);
 }
 
 bool LTOCodeGenerator::determineTarget(std::string &errMsg) {
   if (TargetMach)
     return true;
 
-  std::string TripleStr = IRLinker.getModule()->getTargetTriple();
+  std::string TripleStr = MergedModule->getTargetTriple();
   if (TripleStr.empty()) {
     TripleStr = sys::getDefaultTargetTriple();
-    IRLinker.getModule()->setTargetTriple(TripleStr);
+    MergedModule->setTargetTriple(TripleStr);
   }
   llvm::Triple Triple(TripleStr);
 
   // create target machine from info for merged modules
   const Target *march = TargetRegistry::lookupTarget(TripleStr, errMsg);
   if (!march)
     return false;
 
static void accumulateAndSortLibcalls(std::vector<StringRef> &Libcalls,
   array_pod_sort(Libcalls.begin(), Libcalls.end());
   Libcalls.erase(std::unique(Libcalls.begin(), Libcalls.end()),
                  Libcalls.end());
 }
 
 void LTOCodeGenerator::applyScopeRestrictions() {
   if (ScopeRestrictionsDone || !ShouldInternalize)
     return;
-  Module *MergedModule = IRLinker.getModule();
 
   // Start off with a verification pass.
   legacy::PassManager passes;
   passes.add(createVerifierPass());
 
   // mark which symbols can not be internalized
   Mangler Mangler;
   std::vector<const char*> MustPreserveList;

 /// Optimize merged modules using various IPO passes
 bool LTOCodeGenerator::optimize(bool DisableInline,
                                 bool DisableGVNLoadPRE,
                                 bool DisableVectorization,
                                 std::string &errMsg) {
   if (!this->determineTarget(errMsg))
     return false;
 
-  Module *MergedModule = IRLinker.getModule();
-
   // Mark which symbols can not be internalized
   this->applyScopeRestrictions();
 
   // Instantiate the pass manager to organize the passes.
   legacy::PassManager passes;
 
   // Add an appropriate DataLayout instance for this module...
   MergedModule->setDataLayout(TargetMach->createDataLayout());
bool LTOCodeGenerator::optimize(bool DisableInline,
   return true;
 }
 
 bool LTOCodeGenerator::compileOptimized(raw_pwrite_stream &out,
                                         std::string &errMsg) {
   if (!this->determineTarget(errMsg))
     return false;
 
-  Module *MergedModule = IRLinker.getModule();
-
   legacy::PassManager codeGenPasses;
 
   // If the bitcode files contain ARC code and were compiled with optimization,
   // the ObjCARCContractPass must be run, so do it unconditionally here.
   codeGenPasses.add(createObjCARCContractPass());
 
   if (TargetMach->addPassesToEmitFile(codeGenPasses, out,
                                       TargetMachine::CGFT_ObjectFile)) {

llvm/trunk/tools/llvm-lto/llvm-lto.cpp

for (unsigned I = 0; I < NumSyms; ++I) {
       if (Scope != LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN)
         KeptDSOSyms.push_back(Name);
     }
 
     // We use the first input module as the destination module when
     // SetMergedModule is true.
     if (SetMergedModule && i == BaseArg) {
       // Transfer ownership to the code generator.
-      CodeGen.setModule(Module.release());
+      CodeGen.setModule(std::move(Module));
     } else if (!CodeGen.addModule(Module.get()))
       return 1;
   }
 
   // Add all the exported symbols to the table of symbols to preserve.
   for (unsigned i = 0; i < ExportedSymbols.size(); ++i)
     CodeGen.addMustPreserveSymbol(ExportedSymbols[i].c_str());
 

llvm/trunk/tools/lto/lto.cpp

 
 void lto_codegen_dispose(lto_code_gen_t cg) { delete unwrap(cg); }
 
 bool lto_codegen_add_module(lto_code_gen_t cg, lto_module_t mod) {
   return !unwrap(cg)->addModule(unwrap(mod));
 }
 
 void lto_codegen_set_module(lto_code_gen_t cg, lto_module_t mod) {
-  unwrap(cg)->setModule(unwrap(mod));
+  unwrap(cg)->setModule(std::unique_ptr<LTOModule>(unwrap(mod)));
 }
 
 bool lto_codegen_set_debug_model(lto_code_gen_t cg, lto_debug_model debug) {
   unwrap(cg)->setDebugInfo(debug);
   return false;
 }
 
 bool lto_codegen_set_pic_model(lto_code_gen_t cg, lto_codegen_model model) {