Import LLVM r73984.

It seems I keep importing sources at very unlucky moments. Let's see
what this revision of LLVM does.

1 files changed, 222 insertions, 0 deletions

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;
+}