Always support masm syntax when intel dialect is active

[serge-sans-paille]

Summary

Instead of activating masm syntax by hand, better couple this activation to the syntax dialect choice.
This also fixes https://bugzilla.redhat.com/show_bug.cgi?id=1692486.

[serge-sans-paille]

@rnk, @mcrosier : up :-)

[rnk]

Thanks for the reminder, sorry I missed this.

This seems like it's explicitly undoing the effect of D53535 / rL345189. The whole point of that was to *disable* masm-style integer literals in standalone assembly files with .intel_syntax, so I think this is working as intended. GNU as does not accept these types of integer literals:

$ cat t.s
	.intel_syntax noprefix
	mov eax, 0dbeefh
$ as t.s -o t.o && llvm-objdump -d t.o
t.s: Assembler messages:
t.s:2: Error: junk `beefh' after expression

By default, the standalone assembly parser aims for GNU as compatibility, so I don't think we want to change this behavior. I think if we want to support using -h suffixed hex literals, we'll need some new flag to control "masm" integer literals, or maybe just hex literals ending in 'h'.

I think there is a desire to add some kind of ml64-compatible assembler to LLVM, so there is a long term desire to have a new masm mode.

[serge-sans-paille]

GNU as compatibility totally makes sense, dropping the patch, and thanks for the detailed answer!

lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp

void AsmPrinter::EmitInlineAsm(StringRef Str, const MCSubtargetInfo &STI,
   std::unique_ptr<MCInstrInfo> MII(TM.getTarget().createMCInstrInfo());
   std::unique_ptr<MCTargetAsmParser> TAP(TM.getTarget().createMCAsmParser(
       STI, *Parser, *MII, MCOptions));
   if (!TAP)
     report_fatal_error("Inline asm not supported by this streamer because"
                        " we don't have an asm parser for this target\n");
   Parser->setAssemblerDialect(Dialect);
   Parser->setTargetParser(*TAP.get());
-  // Enable lexing Masm binary and hex integer literals in intel inline
-  // assembly.
-  if (Dialect == InlineAsm::AD_Intel)
-    Parser->getLexer().setLexMasmIntegers(true);
 
   emitInlineAsmStart();
   // Don't implicitly switch to the text section before the asm.
   int Res = Parser->Run(/*NoInitialTextSection*/ true,
                         /*NoFinalize*/ true);
   emitInlineAsmEnd(STI, &TAP->getSTI());
 
   if (Res && !DiagInfo->DiagHandler)

lib/MC/MCParser/AsmParser.cpp

 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/BinaryFormat/Dwarf.h"
+#include "llvm/IR/InlineAsm.h"
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/MCCodeView.h"
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCDirectives.h"
 #include "llvm/MC/MCDwarf.h"
 #include "llvm/MC/MCExpr.h"
 #include "llvm/MC/MCInstPrinter.h"
 #include "llvm/MC/MCInstrDesc.h"
public:
   unsigned getAssemblerDialect() override {
     if (AssemblerDialect == ~0U)
       return MAI.getAssemblerDialect();
     else
       return AssemblerDialect;
   }
   void setAssemblerDialect(unsigned i) override {
     AssemblerDialect = i;
+    // Enable lexing Masm binary and hex integer literals in intel inline
+    // assembly.
+    getLexer().setLexMasmIntegers(i == InlineAsm::AD_Intel);
   }
 
   void Note(SMLoc L, const Twine &Msg, SMRange Range = None) override;
   bool Warning(SMLoc L, const Twine &Msg, SMRange Range = None) override;
   bool printError(SMLoc L, const Twine &Msg, SMRange Range = None) override;
 
   const AsmToken &Lex() override;
 

test/MC/X86/intel-syntax-2.s

 fsub
 // CHECK: fsubp %st, %st(1)
 fsubr
 // CHECK: fsubrp %st, %st(1)
 fdiv
 // CHECK: fdivp %st, %st(1)
 fdivr
 // CHECK: fdivrp %st, %st(1)
+
+_test4:
+.intel_syntax
+// CHECK: movl $26, -4(%rsp)
+  mov  DWORD PTR [RSP - 4], 1ah