[ms] [llvm-ml] When parsing MASM, "jmp short" instructions are case insensitive

[epastor]

Summary

Handle "short" in a case-insensitive fashion in MASM.

Required to correctly parse z_Windows_NT-586_asm.asm from the OpenMP runtime.

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

bool X86AsmParser::ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
 
   // Hack to skip "short" following Jcc.
   if (isParsingIntelSyntax() &&
       (PatchedName == "jmp" || PatchedName == "jc" || PatchedName == "jnc" ||
        PatchedName == "jcxz" || PatchedName == "jexcz" ||
        (PatchedName.startswith("j") &&
         ParseConditionCode(PatchedName.substr(1)) != X86::COND_INVALID))) {
     StringRef NextTok = Parser.getTok().getString();
-    if (NextTok == "short") {
+    if (Parser.isParsingMasm() ? NextTok.equals_lower("short")
+                               : NextTok == "short") {
       SMLoc NameEndLoc =
           NameLoc.getFromPointer(NameLoc.getPointer() + Name.size());
       // Eat the short keyword.
       Parser.Lex();
       // MS and GAS ignore the short keyword; they both determine the jmp type
       // based on the distance of the label. (NASM does emit different code with
       // and without "short," though.)
       InstInfo->AsmRewrites->emplace_back(AOK_Skip, NameEndLoc,

llvm/test/tools/llvm-ml/jmp_short.asm

+; RUN: llvm-ml -filetype=s %s /Fo - | FileCheck %s
+
+.code
+
+t1:
+  jmp short t1_label
+  jmp SHORT t1_label
+  JmP Short t1_label
+  JMP SHORT t1_label
+  mov eax, eax
+t1_label:
+  ret
+
+; CHECK-LABEL: t1:
+; CHECK-NEXT: jmp t1_label
+; CHECK-NEXT: jmp t1_label
+; CHECK-NEXT: jmp t1_label
+; CHECK-NEXT: jmp t1_label
+; CHECK-NEXT: mov eax, eax
+
+end