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// Copyright 2020 Google, Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package asm
import (
"flag"
"go/types"
"log"
"os"
"github.com/mmcloughlin/avo/build"
"github.com/mmcloughlin/avo/buildtags"
"github.com/mmcloughlin/avo/gotypes"
"github.com/mmcloughlin/avo/ir"
)
// CLI utilities for ASM generator
// AvoContext is an extended context for Avo that conveys information about
// the target architecture. In particular this allows some level of
// abstraction over registers.
type AvoContext struct {
*build.Context
Arch string
}
// Missing instructions from avo.
// INL is the INL instruction.
func (ctx *AvoContext) INL() {
ctx.Instruction(&ir.Instruction{Opcode: "INL"})
}
// INSB is the INSB instruction.
func (ctx *AvoContext) INSB() {
ctx.Instruction(&ir.Instruction{Opcode: "INSB"})
}
// OUTSB is the OUTSB instruction.
func (ctx *AvoContext) OUTSB() {
ctx.Instruction(&ir.Instruction{Opcode: "OUTSB"})
}
// REP is the REP instruction.
func (ctx *AvoContext) REP() {
ctx.Instruction(&ir.Instruction{Opcode: "REP"})
}
// AvoMainFunc is the type of functions that can be used with GenAsm.
type AvoMainFunc func(ctx *AvoContext) error
// GenAsm is our main entry point for ASM code generation.
// It augments avo flags with a "-arch", the content of which is
// exposed in AvoContext. That value also drives the alignments in
// the generated code.
func GenAsm(f AvoMainFunc) {
var arch string
// reset the flagset to allow NewFlags to work.
flag.CommandLine = flag.NewFlagSet(os.Args[0], flag.ExitOnError)
var flags = build.NewFlags(flag.CommandLine)
flag.CommandLine.StringVar(&arch, "arch", "amd64", "arch to use")
flag.Parse()
// This is needed to get proper alignment of the return values.
// amd64 is the global default in avo, but not modifying it might
// result in misalignment of the stack.
gotypes.Sizes = types.SizesFor("gc", arch)
cfg := flags.Config()
ctx := &AvoContext{
Context: build.NewContext(),
Arch: arch,
}
ctx.Constraint(buildtags.Opt("gc"))
if err := f(ctx); err != nil {
log.Fatal(err)
}
os.Exit(build.Main(cfg, ctx.Context))
}
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