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[dev.cc] cmd/asm: the assembler proper
Add main.go, the simple driver for the assembler, and the subdirectory internal/asm, which contains the parser and instruction generator. It's likely that much of the implementation is superstition, or at best experimental phenomenology, but it does generate working binaries. Change-Id: I322a9ae8a20174b6693153f30e39217ba68f8032 Reviewed-on: https://go-review.googlesource.com/3196 Reviewed-by: Russ Cox <rsc@golang.org>
This commit is contained in:
Rob Pike
parent
8642639575
commit
fdeee3a538
533
src/cmd/asm/internal/asm/asm.go
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533
src/cmd/asm/internal/asm/asm.go
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@ -0,0 +1,533 @@
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// Copyright 2014 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package asm
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import (
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"fmt"
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"strings"
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"text/scanner"
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"cmd/asm/internal/addr"
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"cmd/asm/internal/arch"
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"cmd/asm/internal/lex"
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"cmd/internal/obj"
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)
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// TODO: This package has many numeric conversions that should be unnecessary.
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// symbolType returns the extern/static etc. type appropriate for the symbol.
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func (p *Parser) symbolType(a *addr.Addr) int {
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switch a.Register {
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case arch.RFP:
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return p.arch.D_PARAM
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case arch.RSP:
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return p.arch.D_AUTO
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case arch.RSB:
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// See comment in addrToAddr.
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if a.IsImmediateAddress {
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return p.arch.D_ADDR
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}
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if a.IsStatic {
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return p.arch.D_STATIC
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}
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return p.arch.D_EXTERN
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}
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p.errorf("invalid register for symbol %s", a.Symbol)
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return 0
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}
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// TODO: configure the architecture
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func (p *Parser) addrToAddr(a *addr.Addr) obj.Addr {
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out := p.arch.NoAddr
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if a.Has(addr.Symbol) {
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// How to encode the symbols:
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// syntax = Typ,Index
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// $a(SB) = ADDR,EXTERN
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// $a<>(SB) = ADDR,STATIC
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// a(SB) = EXTERN,NONE
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// a<>(SB) = STATIC,NONE
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// The call to symbolType does the first column; we need to fix up Index here.
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out.Type = int16(p.symbolType(a))
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out.Sym = obj.Linklookup(p.linkCtxt, a.Symbol, 0)
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if a.IsImmediateAddress {
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// Index field says whether it's a static.
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switch a.Register {
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case arch.RSB:
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if a.IsStatic {
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out.Index = uint8(p.arch.D_STATIC)
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} else {
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out.Index = uint8(p.arch.D_EXTERN)
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}
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default:
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p.errorf("can't handle immediate address of %s not (SB)\n", a.Symbol)
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}
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}
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} else if a.Has(addr.Register) {
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// TODO: SP is tricky, and this isn't good enough.
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// SP = D_SP
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// 4(SP) = 4(D_SP)
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// x+4(SP) = D_AUTO with sym=x TODO
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out.Type = a.Register
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if a.Register == arch.RSP {
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out.Type = int16(p.arch.SP)
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}
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if a.IsIndirect {
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out.Type += p.arch.D_INDIR
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}
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// a.Register2 handled in the instruction method; it's bizarre.
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}
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if a.Has(addr.Index) {
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out.Index = uint8(a.Index) // TODO: out.Index == p.NoArch.Index should be same type as Register.
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}
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if a.Has(addr.Scale) {
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out.Scale = a.Scale
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}
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if a.Has(addr.Offset) {
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out.Offset = a.Offset
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if a.Is(addr.Offset) {
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// RHS of MOVL $0xf1, 0xf1 // crash
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out.Type = p.arch.D_INDIR + int16(p.arch.D_NONE)
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} else if a.IsImmediateConstant && out.Type == int16(p.arch.D_NONE) {
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out.Type = int16(p.arch.D_CONST)
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}
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}
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if a.Has(addr.Float) {
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out.U.Dval = a.Float
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out.Type = int16(p.arch.D_FCONST)
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}
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if a.Has(addr.String) {
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out.U.Sval = a.String
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out.Type = int16(p.arch.D_SCONST)
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}
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// HACK TODO
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if a.IsIndirect && !a.Has(addr.Register) && a.Has(addr.Index) {
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// LHS of LEAQ 0(BX*8), CX
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out.Type = p.arch.D_INDIR + int16(p.arch.D_NONE)
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}
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return out
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}
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func (p *Parser) link(prog *obj.Prog, doLabel bool) {
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if p.firstProg == nil {
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p.firstProg = prog
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} else {
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p.lastProg.Link = prog
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}
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p.lastProg = prog
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if doLabel {
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p.pc++
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for _, label := range p.pendingLabels {
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if p.labels[label] != nil {
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p.errorf("label %q multiply defined", label)
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}
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p.labels[label] = prog
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}
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p.pendingLabels = p.pendingLabels[0:0]
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}
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prog.Pc = int64(p.pc)
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fmt.Println(p.histLineNum, prog)
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}
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// asmText assembles a TEXT pseudo-op.
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// TEXT runtime·sigtramp(SB),4,$0-0
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func (p *Parser) asmText(word string, operands [][]lex.Token) {
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if len(operands) != 3 {
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p.errorf("expect three operands for TEXT")
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}
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// Operand 0 is the symbol name in the form foo(SB).
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// That means symbol plus indirect on SB and no offset.
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nameAddr := p.address(operands[0])
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if !nameAddr.Is(addr.Symbol|addr.Register|addr.Indirect) || nameAddr.Register != arch.RSB {
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p.errorf("TEXT symbol %q must be an offset from SB", nameAddr.Symbol)
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}
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name := strings.Replace(nameAddr.Symbol, "·", ".", 1)
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// Operand 1 is the text flag, a literal integer.
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flagAddr := p.address(operands[1])
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if !flagAddr.Is(addr.Offset) {
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p.errorf("TEXT flag for %s must be an integer", name)
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}
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flag := int8(flagAddr.Offset)
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// Operand 2 is the frame and arg size.
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// Bizarre syntax: $a-b is two words, not subtraction.
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// We might even see $-b, which means $0-b. Ugly.
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// Assume if it has this syntax that b is a plain constant.
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// Not clear we can do better, but it doesn't matter.
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op := operands[2]
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n := len(op)
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var locals int64
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if n >= 2 && op[n-2].ScanToken == '-' && op[n-1].ScanToken == scanner.Int {
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p.start(op[n-1:])
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locals = int64(p.expr())
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op = op[:n-2]
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}
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args := int64(0)
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if len(op) == 1 && op[0].ScanToken == '$' {
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// Special case for $-8.
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// Done; args is zero.
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} else {
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argsAddr := p.address(op)
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if !argsAddr.Is(addr.ImmediateConstant | addr.Offset) {
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p.errorf("TEXT frame size for %s must be an immediate constant", name)
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}
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args = argsAddr.Offset
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}
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prog := &obj.Prog{
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Ctxt: p.linkCtxt,
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As: int16(p.arch.ATEXT),
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Lineno: int32(p.histLineNum),
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From: obj.Addr{
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Type: int16(p.symbolType(&nameAddr)),
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Index: uint8(p.arch.D_NONE),
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Sym: obj.Linklookup(p.linkCtxt, name, 0),
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Scale: flag,
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},
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To: obj.Addr{
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Index: uint8(p.arch.D_NONE),
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},
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}
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// Encoding of arg and locals depends on architecture.
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switch p.arch.Thechar {
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case '6':
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prog.To.Type = int16(p.arch.D_CONST)
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prog.To.Offset = (locals << 32) | args
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case '8':
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prog.To.Type = p.arch.D_CONST2
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prog.To.Offset = args
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prog.To.Offset2 = int32(locals)
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default:
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p.errorf("internal error: can't encode TEXT arg/frame")
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}
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p.link(prog, true)
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}
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// asmData assembles a DATA pseudo-op.
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// DATA masks<>+0x00(SB)/4, $0x00000000
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func (p *Parser) asmData(word string, operands [][]lex.Token) {
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if len(operands) != 2 {
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p.errorf("expect two operands for DATA")
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}
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// Operand 0 has the general form foo<>+0x04(SB)/4.
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op := operands[0]
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n := len(op)
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if n < 3 || op[n-2].ScanToken != '/' || op[n-1].ScanToken != scanner.Int {
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p.errorf("expect /size for DATA argument")
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}
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scale := p.scale(op[n-1].String())
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op = op[:n-2]
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nameAddr := p.address(op)
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ok := nameAddr.Is(addr.Symbol|addr.Register|addr.Indirect) || nameAddr.Is(addr.Symbol|addr.Register|addr.Indirect|addr.Offset)
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if !ok || nameAddr.Register != arch.RSB {
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p.errorf("DATA symbol %q must be an offset from SB", nameAddr.Symbol)
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}
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name := strings.Replace(nameAddr.Symbol, "·", ".", 1)
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// Operand 1 is an immediate constant or address.
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valueAddr := p.address(operands[1])
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if !valueAddr.IsImmediateConstant && !valueAddr.IsImmediateAddress {
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p.errorf("DATA value must be an immediate constant or address")
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}
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// The addresses must not overlap. Easiest test: require monotonicity.
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if lastAddr, ok := p.dataAddr[name]; ok && nameAddr.Offset < lastAddr {
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p.errorf("overlapping DATA entry for %s", nameAddr.Symbol)
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}
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p.dataAddr[name] = nameAddr.Offset + int64(scale)
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prog := &obj.Prog{
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Ctxt: p.linkCtxt,
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As: int16(p.arch.ADATA),
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Lineno: int32(p.histLineNum),
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From: obj.Addr{
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Type: int16(p.symbolType(&nameAddr)),
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Index: uint8(p.arch.D_NONE),
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Sym: obj.Linklookup(p.linkCtxt, name, 0),
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Offset: nameAddr.Offset,
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Scale: scale,
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},
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To: p.addrToAddr(&valueAddr),
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}
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p.link(prog, false)
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}
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// asmGlobl assembles a GLOBL pseudo-op.
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// GLOBL shifts<>(SB),8,$256
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// GLOBL shifts<>(SB),$256
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func (p *Parser) asmGlobl(word string, operands [][]lex.Token) {
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if len(operands) != 2 && len(operands) != 3 {
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p.errorf("expect two or three operands for GLOBL")
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}
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// Operand 0 has the general form foo<>+0x04(SB).
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nameAddr := p.address(operands[0])
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if !nameAddr.Is(addr.Symbol|addr.Register|addr.Indirect) || nameAddr.Register != arch.RSB {
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p.errorf("GLOBL symbol %q must be an offset from SB", nameAddr.Symbol)
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}
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name := strings.Replace(nameAddr.Symbol, "·", ".", 1)
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// If three operands, middle operand is a scale.
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scale := int8(0)
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op := operands[1]
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if len(operands) == 3 {
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scaleAddr := p.address(op)
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if !scaleAddr.Is(addr.Offset) {
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p.errorf("GLOBL scale must be a constant")
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}
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scale = int8(scaleAddr.Offset)
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op = operands[2]
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}
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// Final operand is an immediate constant.
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sizeAddr := p.address(op)
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if !sizeAddr.Is(addr.ImmediateConstant | addr.Offset) {
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p.errorf("GLOBL size must be an immediate constant")
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}
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size := sizeAddr.Offset
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// log.Printf("GLOBL %s %d, $%d", name, scale, size)
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prog := &obj.Prog{
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Ctxt: p.linkCtxt,
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As: int16(p.arch.AGLOBL),
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Lineno: int32(p.histLineNum),
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From: obj.Addr{
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Type: int16(p.symbolType(&nameAddr)),
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Index: uint8(p.arch.D_NONE),
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Sym: obj.Linklookup(p.linkCtxt, name, 0),
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Offset: nameAddr.Offset,
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Scale: scale,
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},
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To: obj.Addr{
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Type: int16(p.arch.D_CONST),
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Index: uint8(p.arch.D_NONE),
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Offset: size,
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},
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}
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p.link(prog, false)
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}
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// asmPCData assembles a PCDATA pseudo-op.
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// PCDATA $2, $705
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func (p *Parser) asmPCData(word string, operands [][]lex.Token) {
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if len(operands) != 2 {
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p.errorf("expect two operands for PCDATA")
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}
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// Operand 0 must be an immediate constant.
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addr0 := p.address(operands[0])
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if !addr0.Is(addr.ImmediateConstant | addr.Offset) {
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p.errorf("PCDATA value must be an immediate constant")
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}
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value0 := addr0.Offset
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// Operand 1 must be an immediate constant.
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addr1 := p.address(operands[1])
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if !addr1.Is(addr.ImmediateConstant | addr.Offset) {
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p.errorf("PCDATA value must be an immediate constant")
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}
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value1 := addr1.Offset
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// log.Printf("PCDATA $%d, $%d", value0, value1)
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prog := &obj.Prog{
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Ctxt: p.linkCtxt,
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As: int16(p.arch.APCDATA),
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Lineno: int32(p.histLineNum),
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From: obj.Addr{
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Type: int16(p.arch.D_CONST),
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Index: uint8(p.arch.D_NONE),
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Offset: value0,
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},
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To: obj.Addr{
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Type: int16(p.arch.D_CONST),
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Index: uint8(p.arch.D_NONE),
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Offset: value1,
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},
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}
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p.link(prog, true)
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}
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// asmFuncData assembles a FUNCDATA pseudo-op.
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// FUNCDATA $1, funcdata<>+4(SB)
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func (p *Parser) asmFuncData(word string, operands [][]lex.Token) {
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if len(operands) != 2 {
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p.errorf("expect two operands for FUNCDATA")
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}
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// Operand 0 must be an immediate constant.
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valueAddr := p.address(operands[0])
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if !valueAddr.Is(addr.ImmediateConstant | addr.Offset) {
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p.errorf("FUNCDATA value must be an immediate constant")
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}
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value := valueAddr.Offset
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// Operand 1 is a symbol name in the form foo(SB).
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// That means symbol plus indirect on SB and no offset.
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nameAddr := p.address(operands[1])
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if !nameAddr.Is(addr.Symbol|addr.Register|addr.Indirect) || nameAddr.Register != arch.RSB {
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p.errorf("FUNCDATA symbol %q must be an offset from SB", nameAddr.Symbol)
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}
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name := strings.Replace(nameAddr.Symbol, "·", ".", 1)
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// log.Printf("FUNCDATA %s, $%d", name, value)
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prog := &obj.Prog{
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Ctxt: p.linkCtxt,
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As: int16(p.arch.AFUNCDATA),
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Lineno: int32(p.histLineNum),
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From: obj.Addr{
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Type: int16(p.arch.D_CONST),
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Index: uint8(p.arch.D_NONE),
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Offset: value,
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},
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To: obj.Addr{
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Type: int16(p.symbolType(&nameAddr)),
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Index: uint8(p.arch.D_NONE),
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Sym: obj.Linklookup(p.linkCtxt, name, 0),
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},
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}
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p.link(prog, true)
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}
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// asmJump assembles a jump instruction.
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// JMP R1
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// JMP exit
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// JMP 3(PC)
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func (p *Parser) asmJump(op int, a []addr.Addr) {
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var target *addr.Addr
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switch len(a) {
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default:
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p.errorf("jump must have one or two addresses")
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case 1:
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target = &a[0]
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case 2:
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if !a[0].Is(0) {
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p.errorf("two-address jump must have empty first address")
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}
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target = &a[1]
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}
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prog := &obj.Prog{
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Ctxt: p.linkCtxt,
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Lineno: int32(p.histLineNum),
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As: int16(op),
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From: p.arch.NoAddr,
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}
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switch {
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case target.Is(addr.Register):
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// JMP R1
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prog.To = p.addrToAddr(target)
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case target.Is(addr.Symbol):
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// JMP exit
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targetProg := p.labels[target.Symbol]
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if targetProg == nil {
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p.toPatch = append(p.toPatch, Patch{prog, target.Symbol})
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} else {
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p.branch(prog, targetProg)
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}
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case target.Is(addr.Register | addr.Indirect), target.Is(addr.Register | addr.Indirect | addr.Offset):
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// JMP 4(AX)
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if target.Register == arch.RPC {
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prog.To = obj.Addr{
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Type: int16(p.arch.D_BRANCH),
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Index: uint8(p.arch.D_NONE),
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Offset: p.pc + 1 + target.Offset, // +1 because p.pc is incremented in link, below.
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}
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} else {
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prog.To = p.addrToAddr(target)
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}
|
||||
case target.Is(addr.Symbol | addr.Indirect | addr.Register):
|
||||
// JMP main·morestack(SB)
|
||||
if target.Register != arch.RSB {
|
||||
p.errorf("jmp to symbol must be SB-relative")
|
||||
}
|
||||
prog.To = obj.Addr{
|
||||
Type: int16(p.arch.D_BRANCH),
|
||||
Sym: obj.Linklookup(p.linkCtxt, target.Symbol, 0),
|
||||
Index: uint8(p.arch.D_NONE),
|
||||
Offset: target.Offset,
|
||||
}
|
||||
default:
|
||||
p.errorf("cannot assemble jump %+v", target)
|
||||
}
|
||||
p.link(prog, true)
|
||||
}
|
||||
|
||||
func (p *Parser) patch() {
|
||||
for _, patch := range p.toPatch {
|
||||
targetProg := p.labels[patch.label]
|
||||
if targetProg == nil {
|
||||
p.errorf("undefined label %s", patch.label)
|
||||
} else {
|
||||
p.branch(patch.prog, targetProg)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
func (p *Parser) branch(jmp, target *obj.Prog) {
|
||||
jmp.To = obj.Addr{
|
||||
Type: int16(p.arch.D_BRANCH),
|
||||
Index: uint8(p.arch.D_NONE),
|
||||
}
|
||||
jmp.To.U.Branch = target
|
||||
}
|
||||
|
||||
// asmInstruction assembles an instruction.
|
||||
// MOVW R9, (R10)
|
||||
func (p *Parser) asmInstruction(op int, a []addr.Addr) {
|
||||
prog := &obj.Prog{
|
||||
Ctxt: p.linkCtxt,
|
||||
Lineno: int32(p.histLineNum),
|
||||
As: int16(op),
|
||||
}
|
||||
switch len(a) {
|
||||
case 0:
|
||||
prog.From = p.arch.NoAddr
|
||||
prog.To = p.arch.NoAddr
|
||||
case 1:
|
||||
if p.arch.UnaryDestination[op] {
|
||||
prog.From = p.arch.NoAddr
|
||||
prog.To = p.addrToAddr(&a[0])
|
||||
} else {
|
||||
prog.From = p.addrToAddr(&a[0])
|
||||
prog.To = p.arch.NoAddr
|
||||
}
|
||||
case 2:
|
||||
prog.From = p.addrToAddr(&a[0])
|
||||
prog.To = p.addrToAddr(&a[1])
|
||||
// DX:AX as a register pair can only appear on the RHS.
|
||||
// Bizarrely, to obj it's specified by setting index on the LHS.
|
||||
// TODO: can we fix this?
|
||||
if a[1].Has(addr.Register2) {
|
||||
if int(prog.From.Index) != p.arch.D_NONE {
|
||||
p.errorf("register pair operand on RHS must have register on LHS")
|
||||
}
|
||||
prog.From.Index = uint8(a[1].Register2)
|
||||
}
|
||||
case 3:
|
||||
// CMPSD etc.; third operand is imm8, stored in offset, or a register.
|
||||
prog.From = p.addrToAddr(&a[0])
|
||||
prog.To = p.addrToAddr(&a[1])
|
||||
switch {
|
||||
case a[2].Is(addr.Offset):
|
||||
prog.To.Offset = a[2].Offset
|
||||
case a[2].Is(addr.Register):
|
||||
// Strange reodering.
|
||||
prog.To = p.addrToAddr(&a[2])
|
||||
prog.From = p.addrToAddr(&a[1])
|
||||
if !a[0].IsImmediateConstant {
|
||||
p.errorf("expected $value for 1st operand")
|
||||
}
|
||||
prog.To.Offset = a[0].Offset
|
||||
default:
|
||||
p.errorf("expected offset or register for 3rd operand")
|
||||
}
|
||||
default:
|
||||
p.errorf("can't handle instruction with %d operands", len(a))
|
||||
}
|
||||
p.link(prog, true)
|
||||
}
|
||||
94
src/cmd/asm/internal/asm/overflow.go
Normal file
94
src/cmd/asm/internal/asm/overflow.go
Normal file
@ -0,0 +1,94 @@
|
||||
// Copyright 2015 The Go Authors. All rights reserved.
|
||||
// Use of this source code is governed by a BSD-style
|
||||
// license that can be found in the LICENSE file.
|
||||
|
||||
package asm
|
||||
|
||||
/*
|
||||
Tested with uint8s like this:
|
||||
|
||||
for a := 0; a <= 255; a++ {
|
||||
for b := 0; b <= 127; b++ {
|
||||
ovfl := a+b != int(uint8(a)+uint8(b))
|
||||
if addOverflows(uint8(a), uint8(b)) != ovfl {
|
||||
fmt.Printf("%d+%d fails\n", a, b)
|
||||
break
|
||||
}
|
||||
}
|
||||
}
|
||||
for a := 0; a <= 255; a++ {
|
||||
for b := 0; b <= 127; b++ {
|
||||
ovfl := a-b != int(uint8(a)-uint8(b))
|
||||
if subOverflows(uint8(a), uint8(b)) != ovfl {
|
||||
fmt.Printf("%d-%d fails\n", a, b)
|
||||
break
|
||||
}
|
||||
}
|
||||
}
|
||||
for a := 0; a <= 255; a++ {
|
||||
for b := 0; b <= 255; b++ {
|
||||
ovfl := a*b != int(uint8(a)*uint8(b))
|
||||
if mulOverflows(uint8(a), uint8(b)) != ovfl {
|
||||
fmt.Printf("%d*%d fails\n", a, b)
|
||||
}
|
||||
}
|
||||
}
|
||||
*/
|
||||
|
||||
func addOverflows(a, b uint64) bool {
|
||||
return a+b < a
|
||||
}
|
||||
|
||||
func subOverflows(a, b uint64) bool {
|
||||
return a-b > a
|
||||
}
|
||||
|
||||
func mulOverflows(a, b uint64) bool {
|
||||
if a <= 1 || b <= 1 {
|
||||
return false
|
||||
}
|
||||
c := a * b
|
||||
return c/b != a
|
||||
}
|
||||
|
||||
/*
|
||||
For the record, signed overflow:
|
||||
|
||||
const mostNegative = -(mostPositive + 1)
|
||||
const mostPositive = 1<<63 - 1
|
||||
|
||||
func signedAddOverflows(a, b int64) bool {
|
||||
if (a >= 0) != (b >= 0) {
|
||||
// Different signs cannot overflow.
|
||||
return false
|
||||
}
|
||||
if a >= 0 {
|
||||
// Both are positive.
|
||||
return a+b < 0
|
||||
}
|
||||
return a+b >= 0
|
||||
}
|
||||
|
||||
func signedSubOverflows(a, b int64) bool {
|
||||
if (a >= 0) == (b >= 0) {
|
||||
// Same signs cannot overflow.
|
||||
return false
|
||||
}
|
||||
if a >= 0 {
|
||||
// a positive, b negative.
|
||||
return a-b < 0
|
||||
}
|
||||
return a-b >= 0
|
||||
}
|
||||
|
||||
func signedMulOverflows(a, b int64) bool {
|
||||
if a == 0 || b == 0 || a == 1 || b == 1 {
|
||||
return false
|
||||
}
|
||||
if a == mostNegative || b == mostNegative {
|
||||
return true
|
||||
}
|
||||
c := a * b
|
||||
return c/b != a
|
||||
}
|
||||
*/
|
||||
527
src/cmd/asm/internal/asm/parse.go
Normal file
527
src/cmd/asm/internal/asm/parse.go
Normal file
@ -0,0 +1,527 @@
|
||||
// Copyright 2015 The Go Authors. All rights reserved.
|
||||
// Use of this source code is governed by a BSD-style
|
||||
// license that can be found in the LICENSE file.
|
||||
|
||||
// Package asm implements the parser and instruction generator for the assembler.
|
||||
// TODO: Split apart?
|
||||
package asm
|
||||
|
||||
import (
|
||||
"fmt"
|
||||
"log"
|
||||
"os"
|
||||
"strconv"
|
||||
"text/scanner"
|
||||
|
||||
"cmd/asm/internal/addr"
|
||||
"cmd/asm/internal/arch"
|
||||
"cmd/asm/internal/lex"
|
||||
"cmd/internal/obj"
|
||||
)
|
||||
|
||||
type Parser struct {
|
||||
lex lex.TokenReader
|
||||
lineNum int // Line number in source file.
|
||||
histLineNum int // Cumulative line number across source files.
|
||||
errorLine int // (Cumulative) line number of last error.
|
||||
errorCount int // Number of errors.
|
||||
pc int64 // virtual PC; count of Progs; doesn't advance for GLOBL or DATA.
|
||||
input []lex.Token
|
||||
inputPos int
|
||||
pendingLabels []string // Labels to attach to next instruction.
|
||||
labels map[string]*obj.Prog
|
||||
toPatch []Patch
|
||||
addr []addr.Addr
|
||||
arch *arch.Arch
|
||||
linkCtxt *obj.Link
|
||||
firstProg *obj.Prog
|
||||
lastProg *obj.Prog
|
||||
dataAddr map[string]int64 // Most recent address for DATA for this symbol.
|
||||
}
|
||||
|
||||
type Patch struct {
|
||||
prog *obj.Prog
|
||||
label string
|
||||
}
|
||||
|
||||
func NewParser(ctxt *obj.Link, ar *arch.Arch, lexer lex.TokenReader) *Parser {
|
||||
return &Parser{
|
||||
linkCtxt: ctxt,
|
||||
arch: ar,
|
||||
lex: lexer,
|
||||
labels: make(map[string]*obj.Prog),
|
||||
dataAddr: make(map[string]int64),
|
||||
}
|
||||
}
|
||||
|
||||
func (p *Parser) errorf(format string, args ...interface{}) {
|
||||
if p.histLineNum == p.errorLine {
|
||||
// Only one error per line.
|
||||
return
|
||||
}
|
||||
p.errorLine = p.histLineNum
|
||||
// Put file and line information on head of message.
|
||||
format = "%s:%d: " + format + "\n"
|
||||
args = append([]interface{}{p.lex.File(), p.lineNum}, args...)
|
||||
fmt.Fprintf(os.Stderr, format, args...)
|
||||
p.errorCount++
|
||||
if p.errorCount > 10 {
|
||||
log.Fatal("too many errors")
|
||||
}
|
||||
}
|
||||
|
||||
func (p *Parser) Parse() (*obj.Prog, bool) {
|
||||
for p.line() {
|
||||
}
|
||||
if p.errorCount > 0 {
|
||||
return nil, false
|
||||
}
|
||||
p.patch()
|
||||
return p.firstProg, true
|
||||
}
|
||||
|
||||
// WORD op {, op} '\n'
|
||||
func (p *Parser) line() bool {
|
||||
// Skip newlines.
|
||||
var tok lex.ScanToken
|
||||
for {
|
||||
tok = p.lex.Next()
|
||||
// We save the line number here so error messages from this instruction
|
||||
// are labeled with this line. Otherwise we complain after we've absorbed
|
||||
// the terminating newline and the line numbers are off by one in errors.
|
||||
p.lineNum = p.lex.Line()
|
||||
p.histLineNum = lex.HistLine()
|
||||
switch tok {
|
||||
case '\n':
|
||||
continue
|
||||
case scanner.EOF:
|
||||
return false
|
||||
}
|
||||
break
|
||||
}
|
||||
// First item must be an identifier.
|
||||
if tok != scanner.Ident {
|
||||
p.errorf("expected identifier, found %q", p.lex.Text())
|
||||
return false // Might as well stop now.
|
||||
}
|
||||
word := p.lex.Text()
|
||||
operands := make([][]lex.Token, 0, 3)
|
||||
// Zero or more comma-separated operands, one per loop.
|
||||
first := true // Permit ':' to define this as a label.
|
||||
for tok != '\n' && tok != ';' {
|
||||
// Process one operand.
|
||||
items := make([]lex.Token, 0, 3)
|
||||
for {
|
||||
tok = p.lex.Next()
|
||||
if first {
|
||||
if tok == ':' {
|
||||
p.pendingLabels = append(p.pendingLabels, word)
|
||||
return true
|
||||
}
|
||||
first = false
|
||||
}
|
||||
if tok == scanner.EOF {
|
||||
p.errorf("unexpected EOF")
|
||||
return false
|
||||
}
|
||||
if tok == '\n' || tok == ';' || tok == ',' {
|
||||
break
|
||||
}
|
||||
items = append(items, lex.Make(tok, p.lex.Text()))
|
||||
}
|
||||
if len(items) > 0 {
|
||||
operands = append(operands, items)
|
||||
} else if len(operands) > 0 {
|
||||
// Had a comma but nothing after.
|
||||
p.errorf("missing operand")
|
||||
}
|
||||
}
|
||||
i := p.arch.Pseudos[word]
|
||||
if i != 0 {
|
||||
p.pseudo(i, word, operands)
|
||||
return true
|
||||
}
|
||||
i = p.arch.Instructions[word]
|
||||
if i != 0 {
|
||||
p.instruction(i, word, operands)
|
||||
return true
|
||||
}
|
||||
p.errorf("unrecognized instruction %s", word)
|
||||
return true
|
||||
}
|
||||
|
||||
func (p *Parser) instruction(op int, word string, operands [][]lex.Token) {
|
||||
p.addr = p.addr[0:0]
|
||||
for _, op := range operands {
|
||||
p.addr = append(p.addr, p.address(op))
|
||||
}
|
||||
// Is it a jump? TODO
|
||||
if word[0] == 'J' || word == "CALL" {
|
||||
p.asmJump(op, p.addr)
|
||||
return
|
||||
}
|
||||
p.asmInstruction(op, p.addr)
|
||||
}
|
||||
|
||||
func (p *Parser) pseudo(op int, word string, operands [][]lex.Token) {
|
||||
switch op {
|
||||
case p.arch.ATEXT:
|
||||
p.asmText(word, operands)
|
||||
case p.arch.ADATA:
|
||||
p.asmData(word, operands)
|
||||
case p.arch.AGLOBL:
|
||||
p.asmGlobl(word, operands)
|
||||
case p.arch.APCDATA:
|
||||
p.asmPCData(word, operands)
|
||||
case p.arch.AFUNCDATA:
|
||||
p.asmFuncData(word, operands)
|
||||
default:
|
||||
p.errorf("unimplemented: %s", word)
|
||||
}
|
||||
}
|
||||
|
||||
func (p *Parser) start(operand []lex.Token) {
|
||||
p.input = operand
|
||||
p.inputPos = 0
|
||||
}
|
||||
|
||||
// address parses the operand into a link address structure.
|
||||
func (p *Parser) address(operand []lex.Token) addr.Addr {
|
||||
p.start(operand)
|
||||
addr := addr.Addr{}
|
||||
p.operand(&addr)
|
||||
return addr
|
||||
}
|
||||
|
||||
// parse (R). The opening paren is known to be there.
|
||||
// The return value states whether it was a scaled mode.
|
||||
func (p *Parser) parenRegister(a *addr.Addr) bool {
|
||||
p.next()
|
||||
tok := p.next()
|
||||
if tok.ScanToken != scanner.Ident {
|
||||
p.errorf("expected register, got %s", tok)
|
||||
}
|
||||
r, present := p.arch.Registers[tok.String()]
|
||||
if !present {
|
||||
p.errorf("expected register, found %s", tok.String())
|
||||
}
|
||||
a.IsIndirect = true
|
||||
scaled := p.peek() == '*'
|
||||
if scaled {
|
||||
// (R*2)
|
||||
p.next()
|
||||
tok := p.get(scanner.Int)
|
||||
a.Scale = p.scale(tok.String())
|
||||
a.Index = int16(r) // TODO: r should have type int16 but is uint8.
|
||||
} else {
|
||||
if a.HasRegister {
|
||||
p.errorf("multiple indirections")
|
||||
}
|
||||
a.HasRegister = true
|
||||
a.Register = int16(r)
|
||||
}
|
||||
p.expect(')')
|
||||
p.next()
|
||||
return scaled
|
||||
}
|
||||
|
||||
// scale converts a decimal string into a valid scale factor.
|
||||
func (p *Parser) scale(s string) int8 {
|
||||
switch s {
|
||||
case "1", "2", "4", "8":
|
||||
return int8(s[0] - '0')
|
||||
}
|
||||
p.errorf("bad scale: %s", s)
|
||||
return 0
|
||||
}
|
||||
|
||||
// parse (R) or (R)(R*scale). The opening paren is known to be there.
|
||||
func (p *Parser) addressMode(a *addr.Addr) {
|
||||
scaled := p.parenRegister(a)
|
||||
if !scaled && p.peek() == '(' {
|
||||
p.parenRegister(a)
|
||||
}
|
||||
}
|
||||
|
||||
// operand parses a general operand and stores the result in *a.
|
||||
func (p *Parser) operand(a *addr.Addr) bool {
|
||||
if len(p.input) == 0 {
|
||||
p.errorf("empty operand: cannot happen")
|
||||
return false
|
||||
}
|
||||
switch p.peek() {
|
||||
case '$':
|
||||
p.next()
|
||||
switch p.peek() {
|
||||
case scanner.Ident:
|
||||
a.IsImmediateAddress = true
|
||||
p.operand(a) // TODO
|
||||
case scanner.String:
|
||||
a.IsImmediateConstant = true
|
||||
a.HasString = true
|
||||
a.String = p.atos(p.next().String())
|
||||
case scanner.Int, scanner.Float, '+', '-', '~', '(':
|
||||
a.IsImmediateConstant = true
|
||||
if p.have(scanner.Float) {
|
||||
a.HasFloat = true
|
||||
a.Float = p.floatExpr()
|
||||
} else {
|
||||
a.HasOffset = true
|
||||
a.Offset = int64(p.expr())
|
||||
}
|
||||
default:
|
||||
p.errorf("illegal %s in immediate operand", p.next().String())
|
||||
}
|
||||
case '*':
|
||||
p.next()
|
||||
tok := p.next()
|
||||
r, present := p.arch.Registers[tok.String()]
|
||||
if !present {
|
||||
p.errorf("expected register; got %s", tok.String())
|
||||
}
|
||||
a.HasRegister = true
|
||||
a.Register = int16(r)
|
||||
case '(':
|
||||
p.next()
|
||||
if p.peek() == scanner.Ident {
|
||||
p.back()
|
||||
p.addressMode(a)
|
||||
break
|
||||
}
|
||||
p.back()
|
||||
fallthrough
|
||||
case '+', '-', '~', scanner.Int, scanner.Float:
|
||||
if p.have(scanner.Float) {
|
||||
a.HasFloat = true
|
||||
a.Float = p.floatExpr()
|
||||
} else {
|
||||
a.HasOffset = true
|
||||
a.Offset = int64(p.expr())
|
||||
}
|
||||
if p.peek() != scanner.EOF {
|
||||
p.expect('(')
|
||||
p.addressMode(a)
|
||||
}
|
||||
case scanner.Ident:
|
||||
tok := p.next()
|
||||
// Either R or (most general) ident<>+4(SB)(R*scale).
|
||||
if r, present := p.arch.Registers[tok.String()]; present {
|
||||
a.HasRegister = true
|
||||
a.Register = int16(r)
|
||||
// Possibly register pair: DX:AX.
|
||||
if p.peek() == ':' {
|
||||
p.next()
|
||||
tok = p.get(scanner.Ident)
|
||||
a.HasRegister2 = true
|
||||
a.Register2 = int16(p.arch.Registers[tok.String()])
|
||||
}
|
||||
break
|
||||
}
|
||||
// Weirdness with statics: Might now have "<>".
|
||||
if p.peek() == '<' {
|
||||
p.next()
|
||||
p.get('>')
|
||||
a.IsStatic = true
|
||||
}
|
||||
if p.peek() == '+' || p.peek() == '-' {
|
||||
a.HasOffset = true
|
||||
a.Offset = int64(p.expr())
|
||||
}
|
||||
a.Symbol = tok.String()
|
||||
if p.peek() == scanner.EOF {
|
||||
break
|
||||
}
|
||||
// Expect (SB) or (FP)
|
||||
p.expect('(')
|
||||
p.parenRegister(a)
|
||||
if a.Register != arch.RSB && a.Register != arch.RFP && a.Register != arch.RSP {
|
||||
p.errorf("expected SB, FP, or SP offset for %s", tok)
|
||||
}
|
||||
// Possibly have scaled register (CX*8).
|
||||
if p.peek() != scanner.EOF {
|
||||
p.expect('(')
|
||||
p.addressMode(a)
|
||||
}
|
||||
default:
|
||||
p.errorf("unexpected %s in operand", p.next())
|
||||
}
|
||||
p.expect(scanner.EOF)
|
||||
return true
|
||||
}
|
||||
|
||||
// expr = term | term '+' term
|
||||
func (p *Parser) expr() uint64 {
|
||||
value := p.term()
|
||||
for {
|
||||
switch p.peek() {
|
||||
case '+':
|
||||
p.next()
|
||||
x := p.term()
|
||||
if addOverflows(x, value) {
|
||||
p.errorf("overflow in %d+%d", value, x)
|
||||
}
|
||||
value += x
|
||||
case '-':
|
||||
p.next()
|
||||
value -= p.term()
|
||||
case '|':
|
||||
p.next()
|
||||
value |= p.term()
|
||||
case '^':
|
||||
p.next()
|
||||
value ^= p.term()
|
||||
default:
|
||||
return value
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// floatExpr = fconst | '-' floatExpr | '+' floatExpr | '(' floatExpr ')'
|
||||
func (p *Parser) floatExpr() float64 {
|
||||
tok := p.next()
|
||||
switch tok.ScanToken {
|
||||
case '(':
|
||||
v := p.floatExpr()
|
||||
if p.next().ScanToken != ')' {
|
||||
p.errorf("missing closing paren")
|
||||
}
|
||||
return v
|
||||
case '+':
|
||||
return +p.floatExpr()
|
||||
case '-':
|
||||
return -p.floatExpr()
|
||||
case scanner.Float:
|
||||
return p.atof(tok.String())
|
||||
}
|
||||
p.errorf("unexpected %s evaluating float expression", tok)
|
||||
return 0
|
||||
}
|
||||
|
||||
// term = const | term '*' term | '(' expr ')'
|
||||
func (p *Parser) term() uint64 {
|
||||
tok := p.next()
|
||||
switch tok.ScanToken {
|
||||
case '(':
|
||||
v := p.expr()
|
||||
if p.next().ScanToken != ')' {
|
||||
p.errorf("missing closing paren")
|
||||
}
|
||||
return v
|
||||
case '+':
|
||||
return +p.term()
|
||||
case '-':
|
||||
return -p.term()
|
||||
case '~':
|
||||
return ^p.term()
|
||||
case scanner.Int:
|
||||
value := p.atoi(tok.String())
|
||||
for {
|
||||
switch p.peek() {
|
||||
case '*':
|
||||
p.next()
|
||||
value *= p.term() // OVERFLOW?
|
||||
case '/':
|
||||
p.next()
|
||||
value /= p.term()
|
||||
case '%':
|
||||
p.next()
|
||||
value %= p.term()
|
||||
case lex.LSH:
|
||||
p.next()
|
||||
shift := p.term()
|
||||
if shift < 0 {
|
||||
p.errorf("negative left shift %d", shift)
|
||||
}
|
||||
value <<= uint(shift)
|
||||
case lex.RSH:
|
||||
p.next()
|
||||
shift := p.term()
|
||||
if shift < 0 {
|
||||
p.errorf("negative right shift %d", shift)
|
||||
}
|
||||
value >>= uint(shift)
|
||||
case '&':
|
||||
p.next()
|
||||
value &= p.term()
|
||||
default:
|
||||
return value
|
||||
}
|
||||
}
|
||||
}
|
||||
p.errorf("unexpected %s evaluating expression", tok)
|
||||
return 0
|
||||
}
|
||||
|
||||
func (p *Parser) atoi(str string) uint64 {
|
||||
value, err := strconv.ParseUint(str, 0, 64)
|
||||
if err != nil {
|
||||
p.errorf("%s", err)
|
||||
}
|
||||
return value
|
||||
}
|
||||
|
||||
func (p *Parser) atof(str string) float64 {
|
||||
value, err := strconv.ParseFloat(str, 64)
|
||||
if err != nil {
|
||||
p.errorf("%s", err)
|
||||
}
|
||||
return value
|
||||
}
|
||||
|
||||
func (p *Parser) atos(str string) string {
|
||||
value, err := strconv.Unquote(str)
|
||||
if err != nil {
|
||||
p.errorf("%s", err)
|
||||
}
|
||||
return value
|
||||
}
|
||||
|
||||
// EOF represents the end of input.
|
||||
var EOF = lex.Make(scanner.EOF, "EOF")
|
||||
|
||||
func (p *Parser) next() lex.Token {
|
||||
if !p.more() {
|
||||
return EOF
|
||||
}
|
||||
tok := p.input[p.inputPos]
|
||||
p.inputPos++
|
||||
return tok
|
||||
}
|
||||
|
||||
func (p *Parser) back() {
|
||||
p.inputPos--
|
||||
}
|
||||
|
||||
func (p *Parser) peek() lex.ScanToken {
|
||||
if p.more() {
|
||||
return p.input[p.inputPos].ScanToken
|
||||
}
|
||||
return scanner.EOF
|
||||
}
|
||||
|
||||
func (p *Parser) more() bool {
|
||||
return p.inputPos < len(p.input)
|
||||
}
|
||||
|
||||
// get verifies that the next item has the expected type and returns it.
|
||||
func (p *Parser) get(expected lex.ScanToken) lex.Token {
|
||||
p.expect(expected)
|
||||
return p.next()
|
||||
}
|
||||
|
||||
// expect verifies that the next item has the expected type. It does not consume it.
|
||||
func (p *Parser) expect(expected lex.ScanToken) {
|
||||
if p.peek() != expected {
|
||||
p.errorf("expected %s, found %s", expected, p.next())
|
||||
}
|
||||
}
|
||||
|
||||
// have reports whether the remaining tokens contain the specified token.
|
||||
func (p *Parser) have(token lex.ScanToken) bool {
|
||||
for i := p.inputPos; i < len(p.input); i++ {
|
||||
if p.input[i].ScanToken == token {
|
||||
return true
|
||||
}
|
||||
}
|
||||
return false
|
||||
}
|
||||
63
src/cmd/asm/main.go
Normal file
63
src/cmd/asm/main.go
Normal file
@ -0,0 +1,63 @@
|
||||
// Copyright 2014 The Go Authors. All rights reserved.
|
||||
// Use of this source code is governed by a BSD-style
|
||||
// license that can be found in the LICENSE file.
|
||||
|
||||
package main
|
||||
|
||||
import (
|
||||
"flag"
|
||||
"fmt"
|
||||
"go/build"
|
||||
"log"
|
||||
"os"
|
||||
|
||||
"cmd/asm/internal/arch"
|
||||
"cmd/asm/internal/asm"
|
||||
"cmd/asm/internal/flags"
|
||||
"cmd/asm/internal/lex"
|
||||
|
||||
"cmd/internal/obj"
|
||||
)
|
||||
|
||||
func main() {
|
||||
log.SetFlags(0)
|
||||
log.SetPrefix("asm: ")
|
||||
|
||||
GOARCH := build.Default.GOARCH
|
||||
|
||||
architecture := arch.Set(GOARCH)
|
||||
if architecture == nil {
|
||||
log.Fatalf("asm: unrecognized architecture %s", GOARCH)
|
||||
}
|
||||
|
||||
// Is this right?
|
||||
flags.Parse(build.Default.GOROOT, build.Default.GOOS, GOARCH, architecture.Thechar)
|
||||
|
||||
// Create object file, write header.
|
||||
fd, err := os.Create(*flags.OutputFile)
|
||||
if err != nil {
|
||||
log.Fatal(err)
|
||||
}
|
||||
ctxt := obj.Linknew(architecture.LinkArch)
|
||||
if *flags.PrintOut {
|
||||
ctxt.Debugasm = 1
|
||||
}
|
||||
ctxt.Bso = obj.Binitw(os.Stdout)
|
||||
defer obj.Bflush(ctxt.Bso)
|
||||
ctxt.Diag = log.Fatalf
|
||||
output := obj.Binitw(fd)
|
||||
fmt.Fprintf(output, "go object %s %s %s\n", obj.Getgoos(), obj.Getgoarch(), obj.Getgoversion())
|
||||
fmt.Fprintf(output, "!\n")
|
||||
|
||||
lexer := lex.NewLexer(flag.Arg(0), ctxt)
|
||||
parser := asm.NewParser(ctxt, architecture, lexer)
|
||||
pList := obj.Linknewplist(ctxt)
|
||||
var ok bool
|
||||
pList.Firstpc, ok = parser.Parse()
|
||||
if !ok {
|
||||
log.Print("FAIL TODO")
|
||||
os.Exit(1)
|
||||
}
|
||||
obj.Writeobjdirect(ctxt, output)
|
||||
obj.Bflush(output)
|
||||
}
|
||||
Loading…
Reference in New Issue
Block a user