[X86][Experiment] Mangle global variable for inline assembly

[pengfei]

Summary

This is an experiment inspired by @efriedma 's suggestion on D120887.
It seems a more concise way to solve Xiang's problem.

There're some lit failures which I didn't care for now. I can fix them
if we think this is a good approch.

[pengfei]

clang/lib/CodeGen/CGStmt.cpp

2555–2556

I'll use regex to match precisely and replace all.

clang/lib/CodeGen/CGStmt.cpp

 #include "clang/Basic/TargetInfo.h"
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/IR/Assumptions.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/InlineAsm.h"
 #include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/MDBuilder.h"
+#include "llvm/IR/Mangler.h"
 #include "llvm/Support/SaveAndRestore.h"
 
 using namespace clang;
 using namespace CodeGen;
 
 //===----------------------------------------------------------------------===//
 //                              Statement Emission
 //===----------------------------------------------------------------------===//
if (auto *VT = dyn_cast<llvm::VectorType>(Arg->getType()))
                    VT->getPrimitiveSizeInBits().getKnownMinSize());
 
     ArgTypes.push_back(Arg->getType());
     ArgElemTypes.push_back(ArgElemType);
     Args.push_back(Arg);
     Constraints += InputConstraint;
   }
 
+  // Replace global value to its name.
+  if (isa<MSAsmStmt>(&S)) {
+    for (int I = 0, E = Args.size(); I != E; ++I) {
+      if (auto *GV = dyn_cast<llvm::GlobalValue>(Args[I])) {
+        llvm::Mangler M;
+        SmallString<256> MangleName;
+        M.getNameWithPrefix(MangleName, GV, /*CannotUsePrivateLabel=*/true);
+        AsmString.replace(AsmString.find("$" + std::to_string(I)), 2,
+                          MangleName.c_str());
+      }
+    }
+  }
+
   // Append the "input" part of inout constraints.
   for (unsigned i = 0, e = InOutArgs.size(); i != e; i++) {
     ArgTypes.push_back(InOutArgTypes[i]);
     ArgElemTypes.push_back(InOutArgElemTypes[i]);
     Args.push_back(InOutArgs[i]);
   }
   Constraints += InOutConstraints;