For the 'C' disassembler API, add a new ReferenceType for the

SymbolLookUp() call back to return a demangled C++ name to
be used as a comment.

For example darwin's otool(1) program the uses the llvm
disassembler now can produce disassembly like:

callq   __ZNK4llvm6Target20createMCDisassemblerERKNS_15MCSubtargetInfoE ## llvm::Target::createMCDisassembler(llvm::MCSubtargetInfo const&) const

Also fix a bug in LLVMDisasmInstruction() that was not flushing
the raw_svector_ostream for the disassembled instruction string
before copying it to the output buffer that was causing truncation
of the output.

rdar://10173828


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198637 91177308-0d34-0410-b5e6-96231b3b80d8

lib/MC/MCDisassembler/Disassembler.cpp

@@ -298,6 +298,7 @@ size_t LLVMDisasmInstruction(LLVMDisasmContextRef DCR, uint8_t *Bytes,
       emitLatency(DC, Inst);
 
     emitComments(DC, FormattedOS);
+    OS.flush();
 
     assert(OutStringSize != 0 && "Output buffer cannot be zero size");
     size_t OutputSize = std::min(OutStringSize-1, InsnStr.size());