[ms-inline asm] Add support for parsing variables with namespace alias

qualifiers.

This patch only adds support for parsing these identifiers in the
X86AsmParser.  The front-end interface isn't capable of looking up
these identifiers at this point in time.  The end result is the
compiler now errors during object file emission, rather than at
parse time.  Test case coming shortly.
Part of rdar://13499009 and PR13340

llvm-svn: 178566

llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp

@@ -13,6 +13,7 @@
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/ADT/Twine.h"
+#include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCExpr.h"
 #include "llvm/MC/MCInst.h"
 #include "llvm/MC/MCParser/MCAsmLexer.h"
@@ -62,6 +63,8 @@ private:
                                    SMLoc StartLoc);
   X86Operand *ParseIntelBracExpression(unsigned SegReg, uint64_t ImmDisp,
                                        unsigned Size);
+  X86Operand *ParseIntelVarWithQualifier(const MCExpr *&Disp,
+                                         SMLoc &IdentStart);
   X86Operand *ParseMemOperand(unsigned SegReg, SMLoc StartLoc);
 
   X86Operand *CreateMemForInlineAsm(const MCExpr *Disp, SMLoc Start, SMLoc End,
@@ -935,9 +938,13 @@ X86Operand *X86AsmParser::ParseIntelBracExpression(unsigned SegReg,
   if (getLexer().is(AsmToken::Identifier)) {
     if (ParseRegister(TmpReg, Start, End)) {
       const MCExpr *Disp;
+      SMLoc IdentStart = Tok.getLoc();
       if (getParser().parseExpression(Disp, End))
         return 0;
 
+      if (X86Operand *Err = ParseIntelVarWithQualifier(Disp, IdentStart))
+        return Err;
+
       if (getLexer().isNot(AsmToken::RBrac))
         return ErrorOperand(Parser.getTok().getLoc(), "Expected ']' token!");
 
@@ -1046,6 +1053,48 @@ X86Operand *X86AsmParser::ParseIntelBracExpression(unsigned SegReg,
                                Start, End, Size);
 }
 
+// Inline assembly may use variable names with namespace alias qualifiers.
+X86Operand *X86AsmParser::ParseIntelVarWithQualifier(const MCExpr *&Disp,
+                                                     SMLoc &IdentStart) {
+  // We should only see Foo::Bar if we're parsing inline assembly.
+  if (!isParsingInlineAsm())
+    return 0;
+
+  // If we don't see a ':' then there can't be a qualifier.
+  if (getLexer().isNot(AsmToken::Colon))
+    return 0;
+
+
+  bool Done = false;
+  const AsmToken &Tok = Parser.getTok();
+  SMLoc IdentEnd = Tok.getEndLoc();
+  while (!Done) {
+    switch (getLexer().getKind()) {
+    default:
+      Done = true; 
+      break;
+    case AsmToken::Colon:
+      getLexer().Lex(); // Consume ':'.
+      if (getLexer().isNot(AsmToken::Colon))
+        return ErrorOperand(Tok.getLoc(), "Expected ':' token!");
+      getLexer().Lex(); // Consume second ':'.
+      if (getLexer().isNot(AsmToken::Identifier))
+        return ErrorOperand(Tok.getLoc(), "Expected an identifier token!");
+      break;
+    case AsmToken::Identifier:
+      IdentEnd = Tok.getEndLoc();
+      getLexer().Lex(); // Consume the identifier.
+      break;
+    }
+  }
+  size_t Len = IdentEnd.getPointer() - IdentStart.getPointer();
+  StringRef Identifier(IdentStart.getPointer(), Len);
+  MCSymbol *Sym = getContext().GetOrCreateSymbol(Identifier);
+  MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
+  Disp = MCSymbolRefExpr::Create(Sym, Variant, getParser().getContext());
+  return 0;
+}
+
 /// ParseIntelMemOperand - Parse intel style memory operand.
 X86Operand *X86AsmParser::ParseIntelMemOperand(unsigned SegReg,
                                                uint64_t ImmDisp,
@@ -1088,11 +1137,16 @@ X86Operand *X86AsmParser::ParseIntelMemOperand(unsigned SegReg,
   }
 
   const MCExpr *Disp = MCConstantExpr::Create(0, getParser().getContext());
+  SMLoc IdentStart = Tok.getLoc();
   if (getParser().parseExpression(Disp, End))
     return 0;
 
   if (!isParsingInlineAsm())
     return X86Operand::CreateMem(Disp, Start, End, Size);
+
+  if (X86Operand *Err = ParseIntelVarWithQualifier(Disp, IdentStart))
+    return Err;
+
   return CreateMemForInlineAsm(Disp, Start, End, Start, Size);
 }