[ms-inline asm] Support offsets after segment registers

Summary: MASM let's you do stuff like 'MOV FS:20, EAX' and 'MOV EAX, FS:20'

Reviewers: craig.topper, rnk

Reviewed By: rnk

CC: llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D1470

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189407 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 70 insertions, 40 deletions

diff --git a/lib/Target/X86/AsmParser/X86AsmParser.cpp b/lib/Target/X86/AsmParser/X86AsmParser.cpp
index d5d9c5239a..7eb42c4fa5 100644
--- a/lib/Target/X86/AsmParser/X86AsmParser.cpp
+++ b/lib/Target/X86/AsmParser/X86AsmParser.cpp
@@ -497,8 +497,9 @@ private:
   X86Operand *ParseIntelOffsetOfOperator();
   X86Operand *ParseIntelDotOperator(const MCExpr *Disp, const MCExpr *&NewDisp);
   X86Operand *ParseIntelOperator(unsigned OpKind);
-  X86Operand *ParseIntelMemOperand(unsigned SegReg, int64_t ImmDisp,
-                                   SMLoc StartLoc);
+  X86Operand *ParseIntelSegmentOverride(unsigned SegReg, SMLoc Start, unsigned Size);
+  X86Operand *ParseIntelMemOperand(int64_t ImmDisp, SMLoc StartLoc,
+                                   unsigned Size);
   X86Operand *ParseIntelExpression(IntelExprStateMachine &SM, SMLoc &End);
   X86Operand *ParseIntelBracExpression(unsigned SegReg, SMLoc Start,
                                        int64_t ImmDisp, unsigned Size);
@@ -1405,46 +1406,67 @@ X86Operand *X86AsmParser::ParseIntelIdentifier(const MCExpr *&Val,
   return 0;
 }
 
-/// ParseIntelMemOperand - Parse intel style memory operand.
-X86Operand *X86AsmParser::ParseIntelMemOperand(unsigned SegReg,
-                                               int64_t ImmDisp,
-                                               SMLoc Start) {
-  const AsmToken &Tok = Parser.getTok();
-  SMLoc End;
-
-  unsigned Size = getIntelMemOperandSize(Tok.getString());
-  if (Size) {
-    Parser.Lex(); // Eat operand size (e.g., byte, word).
-    if (Tok.getString() != "PTR" && Tok.getString() != "ptr")
-      return ErrorOperand(Start, "Expected 'PTR' or 'ptr' token!");
-    Parser.Lex(); // Eat ptr.
-  }
-
-  // Parse ImmDisp [ BaseReg + Scale*IndexReg + Disp ].
+/// \brief Parse intel style segment override.
+X86Operand *X86AsmParser::ParseIntelSegmentOverride(unsigned SegReg,
+                                                    SMLoc Start,
+                                                    unsigned Size) {
+  assert(SegReg != 0 && "Tried to parse a segment override without a segment!");
+  const AsmToken &Tok = Parser.getTok(); // Eat colon.
+  if (Tok.isNot(AsmToken::Colon))
+    return ErrorOperand(Tok.getLoc(), "Expected ':' token!");
+  Parser.Lex(); // Eat ':'
+
+  int64_t ImmDisp = 0;
   if (getLexer().is(AsmToken::Integer)) {
+    ImmDisp = Tok.getIntVal();
+    AsmToken ImmDispToken = Parser.Lex(); // Eat the integer.
+
     if (isParsingInlineAsm())
-      InstInfo->AsmRewrites->push_back(AsmRewrite(AOK_ImmPrefix,
-                                                  Tok.getLoc()));
-    int64_t ImmDisp = Tok.getIntVal();
-    Parser.Lex(); // Eat the integer.
-    if (getLexer().isNot(AsmToken::LBrac))
-      return ErrorOperand(Start, "Expected '[' token!");
-    return ParseIntelBracExpression(SegReg, Start, ImmDisp, Size);
+      InstInfo->AsmRewrites->push_back(
+          AsmRewrite(AOK_ImmPrefix, ImmDispToken.getLoc()));
+
+    if (getLexer().isNot(AsmToken::LBrac)) {
+      // An immediate following a 'segment register', 'colon' token sequence can
+      // be followed by a bracketed expression.  If it isn't we know we have our
+      // final segment override.
+      const MCExpr *Disp = MCConstantExpr::Create(ImmDisp, getContext());
+      return X86Operand::CreateMem(SegReg, Disp, /*BaseReg=*/0, /*IndexReg=*/0,
+                                   /*Scale=*/1, Start, ImmDispToken.getEndLoc(),
+                                   Size);
+    }
   }
 
   if (getLexer().is(AsmToken::LBrac))
     return ParseIntelBracExpression(SegReg, Start, ImmDisp, Size);
 
-  if (!ParseRegister(SegReg, Start, End)) {
-    // Handel SegReg : [ ... ]
-    if (getLexer().isNot(AsmToken::Colon))
-      return ErrorOperand(Start, "Expected ':' token!");
-    Parser.Lex(); // Eat :
-    if (getLexer().isNot(AsmToken::LBrac))
-      return ErrorOperand(Start, "Expected '[' token!");
-    return ParseIntelBracExpression(SegReg, Start, ImmDisp, Size);
+  const MCExpr *Val;
+  SMLoc End;
+  if (!isParsingInlineAsm()) {
+    if (getParser().parsePrimaryExpr(Val, End))
+      return ErrorOperand(Tok.getLoc(), "Unexpected token!");
+
+    return X86Operand::CreateMem(Val, Start, End, Size);
   }
 
+  InlineAsmIdentifierInfo Info;
+  StringRef Identifier = Tok.getString();
+  if (X86Operand *Err = ParseIntelIdentifier(Val, Identifier, Info,
+                                             /*Unevaluated*/ false, End))
+    return Err;
+  return CreateMemForInlineAsm(/*SegReg=*/0, Val, /*BaseReg=*/0,/*IndexReg=*/0,
+                               /*Scale=*/1, Start, End, Size, Identifier, Info);
+}
+
+/// ParseIntelMemOperand - Parse intel style memory operand.
+X86Operand *X86AsmParser::ParseIntelMemOperand(int64_t ImmDisp, SMLoc Start,
+                                               unsigned Size) {
+  const AsmToken &Tok = Parser.getTok();
+  SMLoc End;
+
+  // Parse ImmDisp [ BaseReg + Scale*IndexReg + Disp ].
+  if (getLexer().is(AsmToken::LBrac))
+    return ParseIntelBracExpression(/*SegReg=*/0, Start, ImmDisp, Size);
+
   const MCExpr *Val;
   if (!isParsingInlineAsm()) {
     if (getParser().parsePrimaryExpr(Val, End))
@@ -1458,7 +1480,7 @@ X86Operand *X86AsmParser::ParseIntelMemOperand(unsigned SegReg,
   if (X86Operand *Err = ParseIntelIdentifier(Val, Identifier, Info,
                                              /*Unevaluated*/ false, End))
     return Err;
-  return CreateMemForInlineAsm(/*SegReg=*/0, Val, /*BaseReg=*/0,/*IndexReg=*/0,
+  return CreateMemForInlineAsm(/*SegReg=*/0, Val, /*BaseReg=*/0, /*IndexReg=*/0,
                                /*Scale=*/1, Start, End, Size, Identifier, Info);
 }
 
@@ -1574,7 +1596,7 @@ X86Operand *X86AsmParser::ParseIntelOperator(unsigned OpKind) {
 
 X86Operand *X86AsmParser::ParseIntelOperand() {
   const AsmToken &Tok = Parser.getTok();
-  SMLoc Start = Tok.getLoc(), End;
+  SMLoc Start, End;
 
   // Offset, length, type and size operators.
   if (isParsingInlineAsm()) {
@@ -1589,6 +1611,15 @@ X86Operand *X86AsmParser::ParseIntelOperand() {
       return ParseIntelOperator(IOK_TYPE);
   }
 
+  unsigned Size = getIntelMemOperandSize(Tok.getString());
+  if (Size) {
+    Parser.Lex(); // Eat operand size (e.g., byte, word).
+    if (Tok.getString() != "PTR" && Tok.getString() != "ptr")
+      return ErrorOperand(Start, "Expected 'PTR' or 'ptr' token!");
+    Parser.Lex(); // Eat ptr.
+  }
+  Start = Tok.getLoc();
+
   // Immediate.
   if (getLexer().is(AsmToken::Integer) || getLexer().is(AsmToken::Minus) ||
       getLexer().is(AsmToken::LParen)) {    
@@ -1620,23 +1651,22 @@ X86Operand *X86AsmParser::ParseIntelOperand() {
                           "before bracketed expr.");
 
     // Parse ImmDisp [ BaseReg + Scale*IndexReg + Disp ].
-    return ParseIntelMemOperand(/*SegReg=*/0, Imm, Start);
+    return ParseIntelMemOperand(Imm, Start, Size);
   }
 
   // Register.
   unsigned RegNo = 0;
   if (!ParseRegister(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.
+    // of a segment override, otherwise this is a normal register reference.
     if (getLexer().isNot(AsmToken::Colon))
       return X86Operand::CreateReg(RegNo, Start, End);
 
-    getParser().Lex(); // Eat the colon.
-    return ParseIntelMemOperand(/*SegReg=*/RegNo, /*Disp=*/0, Start);
+    return ParseIntelSegmentOverride(/*SegReg=*/RegNo, Start, Size);
   }
 
   // Memory operand.
-  return ParseIntelMemOperand(/*SegReg=*/0, /*Disp=*/0, Start);
+  return ParseIntelMemOperand(/*Disp=*/0, Start, Size);
 }
 
 X86Operand *X86AsmParser::ParseATTOperand() {