[MsgPack] Attempt to fix failure on windows expensive checks bot

[tpr]

Summary

My theory is that the failure was caused by me forgetting to flush a
raw_string_ostream.

Change-Id: I9c6208325503b3ee0786b4b688e13fc24a15babf

[gkistanova]

This makes things better, but did not resolve the problem completely.
The following 2 tests are still failing:

********************
Failing Tests (2):
    LLVM :: CodeGen/MIR/AMDGPU/machine-function-info-no-ir.mir
    LLVM :: CodeGen/MIR/AMDGPU/machine-function-info.ll

Both failures has the same reason behind:

>c:\ps4-buildslave2\llvm-clang-x86_64-expensive-checks-win\build\bin\llc.exe -run-pass=none -verify-machineinstrs C:\ps4-buildslave2\llvm-clang-x86_64-expensive-checks-win\build\test\CodeGen\MIR\AMDGPU\Output\machine-function-info.ll.tmp.mir -o -
error: C:\ps4-buildslave2\llvm-clang-x86_64-expensive-checks-win\build\test\CodeGen\MIR\AMDGPU\Output\machine-function-info.ll.tmp.mir:114:21: expected a named register
  scratchRSrcReg:  ''
                    ^

I'll send you the build\test\CodeGen\MIR\AMDGPU\Output\machine-function-info.ll.tmp.mir by e-mail, so you could reproduce the problem locally and play with that.

[tpr]

V2: Also fix the same bug in Matt's AMDGPU MIR roundtrip commit.

[arsenm]

lib/BinaryFormat/MsgPackDocumentYAML.cpp

64 ↗

(On Diff #190794)

Why is this necessary?

lib/Target/AMDGPU/SIMachineFunctionInfo.cpp

326–327 ↗

(On Diff #190794)

Maybe this should be scoped instead of the explicit flush?

[tpr]

lib/BinaryFormat/MsgPackDocumentYAML.cpp

64 ↗

(On Diff #190794)

str() flushes the raw_string_ostream before returning the string.

[tpr]

V3: Adjusted the MIR roundtrip fix to use scoping instead of explicit flush.

[arsenm]

LGTM

[gkistanova]

This version would keep the llvm-clang-x86_64-expensive-checks-win bot happy.
Thanks, Tim!

llvm/trunk/lib/BinaryFormat/MsgPackDocumentYAML.cpp

case msgpack::Type::UInt:
     break;
   case msgpack::Type::Float:
     OS << Float;
     break;
   default:
     llvm_unreachable("not scalar");
     break;
   }
-  return S;
+  return OS.str();
 }
 
 /// Convert the StringRef and use it to set this DocNode (assuming scalar). If
 /// it is a string, copy the string into the Document's strings list so we do
 /// not rely on S having a lifetime beyond this call. Tag is "" or a YAML tag.
 StringRef DocNode::fromString(StringRef S, StringRef Tag) {
   if (Tag == "tag:yaml.org,2002:str")
     Tag = "";

llvm/trunk/lib/Target/AMDGPU/SIMachineFunctionInfo.cpp

 
 MCPhysReg SIMachineFunctionInfo::getNextSystemSGPR() const {
   return AMDGPU::SGPR0 + NumUserSGPRs + NumSystemSGPRs;
 }
 
 static yaml::StringValue regToString(unsigned Reg,
                                      const TargetRegisterInfo &TRI) {
   yaml::StringValue Dest;
+  {
     raw_string_ostream OS(Dest.Value);
     OS << printReg(Reg, &TRI);
+  }
   return Dest;
 }
 
 yaml::SIMachineFunctionInfo::SIMachineFunctionInfo(
   const llvm::SIMachineFunctionInfo& MFI,
   const TargetRegisterInfo &TRI)
   : ExplicitKernArgSize(MFI.getExplicitKernArgSize()),
     MaxKernArgAlign(MFI.getMaxKernArgAlign()),