C++ -gmodules .pcm files don't have the same DW_AT_language dialect

[rastogishubham]

Summary

Because of commit: https://reviews.llvm.org/D104291 the -gmodules .pcm files do not have the same DW_AT_language dialect as the .o file. This was a simple matter of passing the DebugStrictDwarf flag to the PCHContainerGenerator object's CodeGenOpts from the CompilerInstance passed in to it.

Before this change if you ran dwarfdump on the gmodule cache folder you would get DW_AT_language (DW_LANG_C_plus_plus) even when using -std=c++14 with clang

[aprantl]

Thanks! This will need some kind of test.

[rastogishubham]

This change broke the test in ModuleDebugInfo.cpp, I have fixed that issue, and this also will act as a test for this change

clang/lib/CodeGen/ObjectFilePCHContainerOperations.cpp

PCHContainerGenerator(CompilerInstance &CI, const std::string &MainFileName,
     CodeGenOpts.DebugTypeExtRefs = true;
     // When building a module MainFileName is the name of the modulemap file.
     CodeGenOpts.MainFileName =
         LangOpts.CurrentModule.empty() ? MainFileName : LangOpts.CurrentModule;
     CodeGenOpts.setDebugInfo(codegenoptions::FullDebugInfo);
     CodeGenOpts.setDebuggerTuning(CI.getCodeGenOpts().getDebuggerTuning());
     CodeGenOpts.DebugPrefixMap =
         CI.getInvocation().getCodeGenOpts().DebugPrefixMap;
+    CodeGenOpts.DebugStrictDwarf = CI.getCodeGenOpts().DebugStrictDwarf;
   }
 
   ~PCHContainerGenerator() override = default;
 
   void Initialize(ASTContext &Context) override {
     assert(!Ctx && "initialized multiple times");
 
     Ctx = &Context;

clang/test/Modules/ModuleDebugInfo.cpp

 #ifdef MODULES
 @import DebugCXX;
 #endif
 
 // CHECK-MOD: distinct !DICompileUnit(language: DW_LANG_{{.*}}C_plus_plus,
 // CHECK-MOD: distinct !DICompileUnit(language: DW_LANG_{{.*}}C_plus_plus,
 
 // CHECK: distinct !DICompileUnit(language: DW_LANG_{{.*}}C_plus_plus,
-// CHECK-CXX: distinct !DICompileUnit(language: DW_LANG_C_plus_plus,
+// CHECK-CXX: distinct !DICompileUnit(language: DW_LANG_C_plus_plus_11,
 // CHECK-SAME:                    isOptimized: false,
 // CHECK-NOT:                     splitDebugFilename:
 // CHECK-SAME:                    dwoId:
 
 // CHECK: !DICompositeType(tag: DW_TAG_enumeration_type, name: "Enum"
 // CHECK-SAME:             identifier: "_ZTSN8DebugCXX4EnumE")
 // CHECK: !DINamespace(name: "DebugCXX"