[llvm] r276859 - [ARM] Set a non-conflicting comment character for assembly in MSVC mode

[Renato Golin via llvm-commits]

Author: rengolin
Date: Wed Jul 27 07:31:58 2016
New Revision: 276859

URL: http://llvm.org/viewvc/llvm-project?rev=276859&view=rev
Log:
[ARM] Set a non-conflicting comment character for assembly in MSVC mode

Currently, for ARMCOFFMCAsmInfoMicrosoft, no comment character is set, thus the
idefault, '#', is used.

The hash character doesn't work as comment character in ARM assembly, since '#'
is used for immediate values.

The comment character is set to ';', which is the comment character used by MS
armasm.exe. (The microsoft armasm.exe uses a different directive syntax than
what LLVM currently supports though, similar to ARM's armasm.)

This allows inline assembly with immediate constants to be built (and brings the
assembly output from clang -S closer to being possible to assemble).

A test is added that verifies that ';' is correctly interpreted as comments in
this mode, and verifies that assembling code that includes literal constants
with a '#' works.

Patch by Martin Storsjö.

Added:
    llvm/trunk/test/MC/ARM/Windows/literals-comments.s
Modified:
    llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMMCAsmInfo.cpp

Modified: llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMMCAsmInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMMCAsmInfo.cpp?rev=276859&r1=276858&r2=276859&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMMCAsmInfo.cpp (original)
+++ llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMMCAsmInfo.cpp Wed Jul 27 07:31:58 2016
@@ -90,6 +90,7 @@ ARMCOFFMCAsmInfoMicrosoft::ARMCOFFMCAsmI
 
   PrivateGlobalPrefix = "$M";
   PrivateLabelPrefix = "$M";
+  CommentString = ";";
 }
 
 void ARMCOFFMCAsmInfoGNU::anchor() { }

Added: llvm/trunk/test/MC/ARM/Windows/literals-comments.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/ARM/Windows/literals-comments.s?rev=276859&view=auto
==============================================================================
--- llvm/trunk/test/MC/ARM/Windows/literals-comments.s (added)
+++ llvm/trunk/test/MC/ARM/Windows/literals-comments.s Wed Jul 27 07:31:58 2016
@@ -0,0 +1,13 @@
+; RUN: llvm-mc -triple armv7-windows-msvc -filetype obj -o - %s
+
+  .syntax unified
+  .thumb
+
+  .text
+
+  .global function
+  .thumb_func
+function:
+  ; this is a comment
+  mov r0, #42 ; this # was not
+  bx lr