refactor a bunch of X86 specific stuff out to its own file.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73982 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/llvm-mc/MC-X86Specific.cpp b/tools/llvm-mc/MC-X86Specific.cpp
new file mode 100644
index 0000000..45774cf
--- /dev/null
+++ b/tools/llvm-mc/MC-X86Specific.cpp
@@ -0,0 +1,222 @@
+//===- MC-X86Specific.cpp - X86-Specific code for MC ----------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements X86-specific parsing, encoding and decoding stuff for
+// MC.
+//
+//===----------------------------------------------------------------------===//
+
+#include "AsmParser.h"
+#include "llvm/MC/MCInst.h"
+using namespace llvm;
+
+/// X86Operand - Instances of this class represent one X86 machine instruction.
+struct AsmParser::X86Operand {
+ enum {
+ Register,
+ Immediate,
+ Memory
+ } Kind;
+
+ union {
+ struct {
+ unsigned RegNo;
+ } Reg;
+
+ struct {
+ // FIXME: Should be a general expression.
+ int64_t Val;
+ } Imm;
+
+ struct {
+ unsigned SegReg;
+ int64_t Disp; // FIXME: Should be a general expression.
+ unsigned BaseReg;
+ unsigned Scale;
+ unsigned ScaleReg;
+ } Mem;
+ };
+
+ static X86Operand CreateReg(unsigned RegNo) {
+ X86Operand Res;
+ Res.Kind = Register;
+ Res.Reg.RegNo = RegNo;
+ return Res;
+ }
+ static X86Operand CreateImm(int64_t Val) {
+ X86Operand Res;
+ Res.Kind = Immediate;
+ Res.Imm.Val = Val;
+ return Res;
+ }
+ static X86Operand CreateMem(unsigned SegReg, int64_t Disp, unsigned BaseReg,
+ unsigned Scale, unsigned ScaleReg) {
+ X86Operand Res;
+ Res.Kind = Memory;
+ Res.Mem.SegReg = SegReg;
+ Res.Mem.Disp = Disp;
+ Res.Mem.BaseReg = BaseReg;
+ Res.Mem.Scale = Scale;
+ Res.Mem.ScaleReg = ScaleReg;
+ return Res;
+ }
+
+ void AddToMCInst(MCInst &I) {
+ // FIXME: Add in x86 order here.
+ }
+};
+
+bool AsmParser::ParseX86Operand(X86Operand &Op) {
+ switch (Lexer.getKind()) {
+ default:
+ return ParseX86MemOperand(Op);
+ case asmtok::Register:
+ // FIXME: Decode reg #.
+ // FIXME: if a segment register, this could either be just the seg reg, or
+ // the start of a memory operand.
+ Op = X86Operand::CreateReg(123);
+ Lexer.Lex(); // Eat register.
+ return false;
+ case asmtok::Dollar: {
+ // $42 -> immediate.
+ Lexer.Lex();
+ int64_t Val;
+ if (ParseExpression(Val))
+ return TokError("expected integer constant");
+ Op = X86Operand::CreateReg(Val);
+ return false;
+ case asmtok::Star:
+ Lexer.Lex(); // Eat the star.
+
+ if (Lexer.is(asmtok::Register)) {
+ Op = X86Operand::CreateReg(123);
+ Lexer.Lex(); // Eat register.
+ } else if (ParseX86MemOperand(Op))
+ return true;
+
+ // FIXME: Note that these are 'dereferenced' so that clients know the '*' is
+ // there.
+ return false;
+ }
+ }
+}
+
+/// ParseX86MemOperand: segment: disp(basereg, indexreg, scale)
+bool AsmParser::ParseX86MemOperand(X86Operand &Op) {
+ // FIXME: If SegReg ':' (e.g. %gs:), eat and remember.
+ unsigned SegReg = 0;
+
+ // 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 after
+ // it.
+ int64_t Disp = 0;
+ if (Lexer.isNot(asmtok::LParen)) {
+ if (ParseExpression(Disp)) return true;
+
+ // After parsing the base expression we could either have a parenthesized
+ // memory address or not. If not, return now. If so, eat the (.
+ if (Lexer.isNot(asmtok::LParen)) {
+ Op = X86Operand::CreateMem(SegReg, Disp, 0, 0, 0);
+ return false;
+ }
+
+ // Eat the '('.
+ Lexer.Lex();
+ } else {
+ // Okay, we have a '('. We don't know if this is an expression or not, but
+ // so we have to eat the ( to see beyond it.
+ Lexer.Lex(); // Eat the '('.
+
+ if (Lexer.is(asmtok::Register) || Lexer.is(asmtok::Comma)) {
+ // Nothing to do here, fall into the code below with the '(' part of the
+ // memory operand consumed.
+ } else {
+ // It must be an parenthesized expression, parse it now.
+ if (ParseParenExpr(Disp) ||
+ ParseBinOpRHS(1, Disp))
+ return true;
+
+ // After parsing the base expression we could either have a parenthesized
+ // memory address or not. If not, return now. If so, eat the (.
+ if (Lexer.isNot(asmtok::LParen)) {
+ Op = X86Operand::CreateMem(SegReg, Disp, 0, 0, 0);
+ return false;
+ }
+
+ // Eat the '('.
+ Lexer.Lex();
+ }
+ }
+
+ // If we reached here, then we just ate the ( of the memory operand. Process
+ // the rest of the memory operand.
+ unsigned BaseReg = 0, ScaleReg = 0, Scale = 0;
+
+ if (Lexer.is(asmtok::Register)) {
+ BaseReg = 123; // FIXME: decode reg #
+ Lexer.Lex(); // eat the register.
+ }
+
+ if (Lexer.is(asmtok::Comma)) {
+ Lexer.Lex(); // eat the comma.
+
+ if (Lexer.is(asmtok::Register)) {
+ ScaleReg = 123; // FIXME: decode reg #
+ Lexer.Lex(); // eat the register.
+ Scale = 1; // If not specified, the scale defaults to 1.
+ }
+
+ if (Lexer.is(asmtok::Comma)) {
+ Lexer.Lex(); // eat the comma.
+
+ // If present, get and validate scale amount.
+ if (Lexer.is(asmtok::IntVal)) {
+ int64_t ScaleVal = Lexer.getCurIntVal();
+ if (ScaleVal != 1 && ScaleVal != 2 && ScaleVal != 4 && ScaleVal != 8)
+ return TokError("scale factor in address must be 1, 2, 4 or 8");
+ Lexer.Lex(); // eat the scale.
+ Scale = (unsigned)ScaleVal;
+ }
+ }
+ }
+
+ // Ok, we've eaten the memory operand, verify we have a ')' and eat it too.
+ if (Lexer.isNot(asmtok::RParen))
+ return TokError("unexpected token in memory operand");
+ Lexer.Lex(); // Eat the ')'.
+
+ Op = X86Operand::CreateMem(SegReg, Disp, BaseReg, Scale, ScaleReg);
+ return false;
+}
+
+/// ParseX86InstOperands - Parse the operands of an X86 instruction and return
+/// them as the operands of an MCInst.
+bool AsmParser::ParseX86InstOperands(MCInst &Inst) {
+ // If no operands are present, just return.
+ if (Lexer.is(asmtok::EndOfStatement))
+ return false;
+
+ // Read the first operand.
+ X86Operand Op;
+ if (ParseX86Operand(Op))
+ return true;
+ Op.AddToMCInst(Inst);
+
+ while (Lexer.is(asmtok::Comma)) {
+ Lexer.Lex(); // Eat the comma.
+
+ // Parse and remember the operand.
+ Op = X86Operand();
+ if (ParseX86Operand(Op))
+ return true;
+ Op.AddToMCInst(Inst);
+ }
+ return false;
+}