MC intel asm parser: Allow @ at the start of function names.

[thakis]

Summary

Ports parts of r193000 to the intel parser. Fixes part of PR36676.

[hans]

Looks good to me.

[thakis]

r327262, thanks!

lib/Target/X86/AsmParser/X86AsmParser.cpp

case AsmToken::EndOfStatement:
       Done = true;
       break;
     case AsmToken::Real:
       // DotOperator: [ebx].0
       UpdateLocLex = false;
       if (ParseIntelDotOperator(SM, End))
         return true;
       break;
+    case AsmToken::At:
     case AsmToken::String:
     case AsmToken::Identifier: {
       SMLoc IdentLoc = Tok.getLoc();
       StringRef Identifier = Tok.getString();
       UpdateLocLex = false;
       // Register
       unsigned Reg;
-      if (Tok.isNot(AsmToken::String) && !ParseRegister(Reg, IdentLoc, End)) {
+      if (Tok.is(AsmToken::Identifier) && !ParseRegister(Reg, IdentLoc, End)) {
         if (SM.onRegister(Reg, ErrMsg))
           return Error(Tok.getLoc(), ErrMsg);
         break;
       }
       // Operator synonymous ("not", "or" etc.)
       if ((UpdateLocLex = ParseIntelNamedOperator(Identifier, SM)))
         break;
       // Symbol reference, when parsing assembly content
case AsmToken::Identifier: {
       }
       // MS Dot Operator expression
       if (Identifier.count('.') && PrevTK == AsmToken::RBrac) {
         if (ParseIntelDotOperator(SM, End))
           return true;
         break;
       }
       // MS InlineAsm identifier
+      // Call parseIdentifier() to combine @ with the identifier behind it.
+      if (TK == AsmToken::At && Parser.parseIdentifier(Identifier))
+        return Error(IdentLoc, "expected identifier");
       if (ParseIntelInlineAsmIdentifier(Val, Identifier, Info, false, End))
         return true;
       else if (SM.onIdentifierExpr(Val, Identifier, Info, true, ErrMsg))
         return Error(IdentLoc, ErrMsg);
       break;
     }
     case AsmToken::Integer: {
       // Look for 'b' or 'f' following an Integer as a directional label

test/MC/COFF/tricky-names.ll

 ; Check how tricky symbols are printed in the asm output.
 ; RUN: llc -mtriple=i686-pc-win32 %s -o - | FileCheck %s --check-prefix=ASM
+; RUN: llc -mtriple=i686-pc-win32 %s -x86-asm-syntax=intel -o - | FileCheck %s --check-prefix=ASM
 
-; Check that we can roundtrip these names through our assembler.
+; Check that we can roundtrip these names through our assembler,
+; in both at&t and intel syntax.
 ; RUN: llc -mtriple=i686-pc-win32 %s -o - | llvm-mc -triple i686-pc-win32 -filetype=obj | llvm-readobj -t | FileCheck %s --check-prefix=READOBJ
+; RUN: llc -mtriple=i686-pc-win32 -x86-asm-syntax=intel %s -o - | llvm-mc -triple i686-pc-win32 -filetype=obj | llvm-readobj -t | FileCheck %s --check-prefix=READOBJ
 
 
 @"\01??__E_Generic_object@?$_Error_objects@H@std@@YAXXZ" = global i32 0
 @"\01__ZL16ExceptionHandlerP19_EXCEPTION_POINTERS@4" = global i32 0
 @"\[e-mail]" = global i32 0
 
 define weak i32 @"\01??_B?$num_put@_WV?$back_insert_iterator@V?$basic_string@_WU?$char_traits@_W@std@@V?$allocator@_W@2@@std@@@std@@@std@@51"() section ".text" {
   %a = load i32, i32* @"\01??__E_Generic_object@?$_Error_objects@H@std@@YAXXZ"