Change debug-info-for-profiling from a TargetOption to a function attribute.

[danielcdh]

Summary

cfe change for https://reviews.llvm.org/D29203

[danielcdh]

change to use module flag.

[mehdi_amini]

lib/CodeGen/CodeGenModule.cpp

452

Why should we warn on mismatch?

[danielcdh]

lib/CodeGen/CodeGenModule.cpp

452

In theory, we expect this to be the same across all modules. Otherwise when we use this binary for profiling, we may get inaccurate profiles.

[mehdi_amini]

lib/CodeGen/CodeGenModule.cpp

452

Oh I thought about the "unset" case but we wouldn't warn in this case.

Indeed we never even should have this flag with a zero value.

[mehdi_amini]

lib/CodeGen/CodeGenModule.cpp

452

Unless you really intend to get a warning on mismatch, in which case you should always emit the flag, but with a zero value when not enabled.
I'd need more thought to really grasp all the consequences :)

[danielcdh]

update

[dblaikie]

Oops, forgot to write stuff so the approval appears on-list.

Anyway - looks good/approved.

lib/CodeGen/BackendUtil.cpp

case CodeGenOptions::FPC_Fast:
     Options.AllowFPOpFusion = llvm::FPOpFusion::Fast;
     break;
   }
 
   Options.UseInitArray = CodeGenOpts.UseInitArray;
   Options.DisableIntegratedAS = CodeGenOpts.DisableIntegratedAS;
   Options.CompressDebugSections = CodeGenOpts.CompressDebugSections;
   Options.RelaxELFRelocations = CodeGenOpts.RelaxELFRelocations;
-  Options.DebugInfoForProfiling = CodeGenOpts.DebugInfoForProfiling;
 
   // Set EABI version.
   Options.EABIVersion = llvm::StringSwitch<llvm::EABI>(TargetOpts.EABIVersion)
                             .Case("4", llvm::EABI::EABI4)
                             .Case("5", llvm::EABI::EABI5)
                             .Case("gnu", llvm::EABI::GNU)
                             .Default(llvm::EABI::Default);
 

lib/CodeGen/CodeGenModule.cpp

getModule().addModuleFlag(llvm::Module::Require,
                               llvm::MDNode::get(VMContext, Ops));
   }
   if (DebugInfo)
     // We support a single version in the linked module. The LLVM
     // parser will drop debug info with a different version number
     // (and warn about it, too).
     getModule().addModuleFlag(llvm::Module::Warning, "Debug Info Version",
                               llvm::DEBUG_METADATA_VERSION);
+  if (CodeGenOpts.DebugInfoForProfiling)
+    getModule().addModuleFlag(llvm::Module::Warning, "DebugInfoForProfiling", 1);
 
   // We need to record the widths of enums and wchar_t, so that we can generate
   // the correct build attributes in the ARM backend.
   llvm::Triple::ArchType Arch = Context.getTargetInfo().getTriple().getArch();
   if (   Arch == llvm::Triple::arm
       || Arch == llvm::Triple::armeb
       || Arch == llvm::Triple::thumb
       || Arch == llvm::Triple::thumbeb) {