mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-08-30 05:29:47 +00:00
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73875 91177308-0d34-0410-b5e6-96231b3b80d8
301 lines
8.1 KiB
C++
301 lines
8.1 KiB
C++
//===- AsmParser.cpp - Parser for Assembly Files --------------------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This class implements the parser for assembly files.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "AsmParser.h"
|
|
#include "llvm/Support/SourceMgr.h"
|
|
#include "llvm/Support/raw_ostream.h"
|
|
using namespace llvm;
|
|
|
|
bool AsmParser::Error(SMLoc L, const char *Msg) {
|
|
Lexer.PrintMessage(L, Msg);
|
|
return true;
|
|
}
|
|
|
|
bool AsmParser::TokError(const char *Msg) {
|
|
Lexer.PrintMessage(Lexer.getLoc(), Msg);
|
|
return true;
|
|
}
|
|
|
|
bool AsmParser::Run() {
|
|
// Prime the lexer.
|
|
Lexer.Lex();
|
|
|
|
while (Lexer.isNot(asmtok::Eof))
|
|
if (ParseStatement())
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
/// EatToEndOfStatement - Throw away the rest of the line for testing purposes.
|
|
void AsmParser::EatToEndOfStatement() {
|
|
while (Lexer.isNot(asmtok::EndOfStatement) &&
|
|
Lexer.isNot(asmtok::Eof))
|
|
Lexer.Lex();
|
|
|
|
// Eat EOL.
|
|
if (Lexer.is(asmtok::EndOfStatement))
|
|
Lexer.Lex();
|
|
}
|
|
|
|
|
|
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;
|
|
}
|
|
};
|
|
|
|
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(0);
|
|
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:
|
|
// * %eax
|
|
// * <memaddress>
|
|
// Note that these are both "dereferenced".
|
|
}
|
|
}
|
|
|
|
/// 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 {
|
|
// FIXME: Call ParseParenExpression with the leading ( consumed.
|
|
return TokError("FIXME: Paren expr not implemented yet!");
|
|
}
|
|
}
|
|
|
|
// 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;
|
|
}
|
|
|
|
|
|
/// ParseExpression - Parse an expression and return it.
|
|
/// FIXME: This should handle real expressions, we do something trivial for now.
|
|
bool AsmParser::ParseExpression(int64_t &Res) {
|
|
switch (Lexer.getKind()) {
|
|
default:
|
|
return TokError("unknown token in expression");
|
|
case asmtok::Identifier:
|
|
// This is a label, this should be parsed as part of an expression, to
|
|
// handle things like LFOO+4
|
|
Res = 0; // FIXME.
|
|
Lexer.Lex(); // Eat identifier.
|
|
return false;
|
|
case asmtok::IntVal:
|
|
Res = Lexer.getCurIntVal();
|
|
Lexer.Lex(); // Eat identifier.
|
|
return false;
|
|
}
|
|
}
|
|
|
|
|
|
|
|
|
|
/// ParseStatement:
|
|
/// ::= EndOfStatement
|
|
/// ::= Label* Directive ...Operands... EndOfStatement
|
|
/// ::= Label* Identifier OperandList* EndOfStatement
|
|
bool AsmParser::ParseStatement() {
|
|
switch (Lexer.getKind()) {
|
|
default:
|
|
return TokError("unexpected token at start of statement");
|
|
case asmtok::EndOfStatement:
|
|
Lexer.Lex();
|
|
return false;
|
|
case asmtok::Identifier:
|
|
break;
|
|
// TODO: Recurse on local labels etc.
|
|
}
|
|
|
|
// If we have an identifier, handle it as the key symbol.
|
|
SMLoc IDLoc = Lexer.getLoc();
|
|
std::string IDVal = Lexer.getCurStrVal();
|
|
|
|
// Consume the identifier, see what is after it.
|
|
if (Lexer.Lex() == asmtok::Colon) {
|
|
// identifier ':' -> Label.
|
|
Lexer.Lex();
|
|
return ParseStatement();
|
|
}
|
|
|
|
// Otherwise, we have a normal instruction or directive.
|
|
if (IDVal[0] == '.') {
|
|
Lexer.PrintMessage(IDLoc, "warning: ignoring directive for now");
|
|
EatToEndOfStatement();
|
|
return false;
|
|
}
|
|
|
|
// If it's an instruction, parse an operand list.
|
|
std::vector<X86Operand> Operands;
|
|
|
|
// Read the first operand, if present. Note that we require a newline at the
|
|
// end of file, so we don't have to worry about Eof here.
|
|
if (Lexer.isNot(asmtok::EndOfStatement)) {
|
|
X86Operand Op;
|
|
if (ParseX86Operand(Op))
|
|
return true;
|
|
Operands.push_back(Op);
|
|
}
|
|
|
|
while (Lexer.is(asmtok::Comma)) {
|
|
Lexer.Lex(); // Eat the comma.
|
|
|
|
// Parse and remember the operand.
|
|
X86Operand Op;
|
|
if (ParseX86Operand(Op))
|
|
return true;
|
|
Operands.push_back(Op);
|
|
}
|
|
|
|
if (Lexer.isNot(asmtok::EndOfStatement))
|
|
return TokError("unexpected token in operand list");
|
|
|
|
// Eat the end of statement marker.
|
|
Lexer.Lex();
|
|
|
|
// Instruction is good, process it.
|
|
outs() << "Found instruction: " << IDVal << " with " << Operands.size()
|
|
<< " operands.\n";
|
|
|
|
// Skip to end of line for now.
|
|
return false;
|
|
}
|