teach the x86 asm parser how to handle segment prefixes
in memory operands. rdar://7874844
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101661 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/AsmParser/X86AsmParser.cpp b/lib/Target/X86/AsmParser/X86AsmParser.cpp
index 47873d1..da01350 100644
--- a/lib/Target/X86/AsmParser/X86AsmParser.cpp
+++ b/lib/Target/X86/AsmParser/X86AsmParser.cpp
@@ -44,7 +44,7 @@
bool ParseRegister(unsigned &RegNo, SMLoc &StartLoc, SMLoc &EndLoc);
X86Operand *ParseOperand();
- X86Operand *ParseMemOperand();
+ X86Operand *ParseMemOperand(unsigned SegReg, SMLoc StartLoc);
bool ParseDirectiveWord(unsigned Size, SMLoc L);
@@ -368,14 +368,22 @@
X86Operand *X86ATTAsmParser::ParseOperand() {
switch (getLexer().getKind()) {
default:
- return ParseMemOperand();
+ // Parse a memory operand with no segment register.
+ return ParseMemOperand(0, Parser.getTok().getLoc());
case AsmToken::Percent: {
- // FIXME: if a segment register, this could either be just the seg reg, or
- // the start of a memory operand.
+ // Read the register.
unsigned RegNo;
SMLoc Start, End;
if (ParseRegister(RegNo, Start, End)) return 0;
- return X86Operand::CreateReg(RegNo, Start, End);
+
+ // If this is a segment register followed by a ':', then this is the start
+ // of a memory reference, otherwise this is a normal register reference.
+ if (getLexer().isNot(AsmToken::Colon))
+ return X86Operand::CreateReg(RegNo, Start, End);
+
+
+ getParser().Lex(); // Eat the colon.
+ return ParseMemOperand(RegNo, Start);
}
case AsmToken::Dollar: {
// $42 -> immediate.
@@ -389,13 +397,10 @@
}
}
-/// ParseMemOperand: segment: disp(basereg, indexreg, scale)
-X86Operand *X86ATTAsmParser::ParseMemOperand() {
- SMLoc MemStart = Parser.getTok().getLoc();
-
- // FIXME: If SegReg ':' (e.g. %gs:), eat and remember.
- unsigned SegReg = 0;
-
+/// ParseMemOperand: segment: disp(basereg, indexreg, scale). The '%ds:' prefix
+/// has already been parsed if present.
+X86Operand *X86ATTAsmParser::ParseMemOperand(unsigned SegReg, SMLoc MemStart) {
+
// We have to disambiguate a parenthesized expression "(4+5)" from the start
// of a memory operand with a missing displacement "(%ebx)" or "(,%eax)". The
// only way to do this without lookahead is to eat the '(' and see what is