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https://github.com/c64scene-ar/llvm-6502.git
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73867 91177308-0d34-0410-b5e6-96231b3b80d8
185 lines
4.6 KiB
C++
185 lines
4.6 KiB
C++
//===- AsmParser.cpp - Parser for Assembly Files --------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This class implements the parser for assembly files.
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//
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//===----------------------------------------------------------------------===//
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#include "AsmParser.h"
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#include "llvm/Support/SourceMgr.h"
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#include "llvm/Support/raw_ostream.h"
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using namespace llvm;
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bool AsmParser::Error(SMLoc L, const char *Msg) {
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Lexer.PrintMessage(L, Msg);
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return true;
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}
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bool AsmParser::TokError(const char *Msg) {
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Lexer.PrintMessage(Lexer.getLoc(), Msg);
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return true;
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}
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bool AsmParser::Run() {
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// Prime the lexer.
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Lexer.Lex();
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while (Lexer.isNot(asmtok::Eof))
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if (ParseStatement())
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return true;
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return false;
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}
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/// EatToEndOfStatement - Throw away the rest of the line for testing purposes.
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void AsmParser::EatToEndOfStatement() {
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while (Lexer.isNot(asmtok::EndOfStatement) &&
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Lexer.isNot(asmtok::Eof))
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Lexer.Lex();
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// Eat EOL.
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if (Lexer.is(asmtok::EndOfStatement))
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Lexer.Lex();
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}
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struct AsmParser::X86Operand {
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enum {
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Register,
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Immediate
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} Kind;
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union {
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struct {
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unsigned RegNo;
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} Reg;
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struct {
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// FIXME: Should be a general expression.
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int64_t Val;
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} Imm;
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};
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static X86Operand CreateReg(unsigned RegNo) {
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X86Operand Res;
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Res.Kind = Register;
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Res.Reg.RegNo = RegNo;
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return Res;
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}
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static X86Operand CreateImm(int64_t Val) {
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X86Operand Res;
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Res.Kind = Immediate;
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Res.Imm.Val = Val;
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return Res;
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}
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};
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bool AsmParser::ParseX86Operand(X86Operand &Op) {
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switch (Lexer.getKind()) {
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default:
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return TokError("unknown token at start of instruction operand");
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case asmtok::Register:
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// FIXME: Decode reg #.
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Op = X86Operand::CreateReg(0);
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Lexer.Lex(); // Eat register.
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return false;
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case asmtok::Dollar:
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// $42 -> immediate.
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Lexer.Lex();
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// FIXME: Parse an arbitrary expression here, like $(4+5)
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if (Lexer.isNot(asmtok::IntVal))
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return TokError("expected integer constant");
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Op = X86Operand::CreateReg(Lexer.getCurIntVal());
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Lexer.Lex(); // Eat register.
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return false;
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case asmtok::Identifier:
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// This is a label, this should be parsed as part of an expression, to
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// handle things like LFOO+4
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Op = X86Operand::CreateImm(0); // FIXME.
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Lexer.Lex(); // Eat identifier.
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return false;
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//case asmtok::Star:
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// * %eax
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// * <memaddress>
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// Note that these are both "dereferenced".
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}
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}
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/// ParseStatement:
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/// ::= EndOfStatement
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/// ::= Label* Directive ...Operands... EndOfStatement
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/// ::= Label* Identifier OperandList* EndOfStatement
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bool AsmParser::ParseStatement() {
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switch (Lexer.getKind()) {
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default:
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return TokError("unexpected token at start of statement");
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case asmtok::EndOfStatement:
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Lexer.Lex();
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return false;
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case asmtok::Identifier:
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break;
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// TODO: Recurse on local labels etc.
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}
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// If we have an identifier, handle it as the key symbol.
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SMLoc IDLoc = Lexer.getLoc();
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std::string IDVal = Lexer.getCurStrVal();
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// Consume the identifier, see what is after it.
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if (Lexer.Lex() == asmtok::Colon) {
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// identifier ':' -> Label.
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Lexer.Lex();
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return ParseStatement();
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}
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// Otherwise, we have a normal instruction or directive.
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if (IDVal[0] == '.') {
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Lexer.PrintMessage(IDLoc, "warning: ignoring directive for now");
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EatToEndOfStatement();
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return false;
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}
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// If it's an instruction, parse an operand list.
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std::vector<X86Operand> Operands;
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// Read the first operand, if present. Note that we require a newline at the
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// end of file, so we don't have to worry about Eof here.
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if (Lexer.isNot(asmtok::EndOfStatement)) {
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X86Operand Op;
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if (ParseX86Operand(Op))
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return true;
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Operands.push_back(Op);
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}
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while (Lexer.is(asmtok::Comma)) {
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Lexer.Lex(); // Eat the comma.
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// Parse and remember the operand.
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X86Operand Op;
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if (ParseX86Operand(Op))
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return true;
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Operands.push_back(Op);
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}
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if (Lexer.isNot(asmtok::EndOfStatement))
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return TokError("unexpected token in operand list");
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// Eat the end of statement marker.
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Lexer.Lex();
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// Instruction is good, process it.
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outs() << "Found instruction: " << IDVal << " with " << Operands.size()
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<< " operands.\n";
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// Skip to end of line for now.
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return false;
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}
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