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3f2cb493e5
Reuse the same mechanisms for handling universal builtins like len to handle unsafe.Sizeof, etc. Allows us to drop package unsafe's export data, and simplifies some code. Updates #17508. Change-Id: I620e0617c24e57e8a2d7cccd0e2de34608779656 Reviewed-on: https://go-review.googlesource.com/31433 Run-TryBot: Matthew Dempsky <mdempsky@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Robert Griesemer <gri@golang.org>
93 lines
2 KiB
Go
93 lines
2 KiB
Go
// Copyright 2009 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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// +build ignore
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// Generate builtin.go from builtin/runtime.go.
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// Run this after changing builtin/runtime.go
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// or after changing the export metadata format in the compiler.
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// Either way, you need to have a working compiler binary first.
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// See bexport.go for how to make an export metadata format change.
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package main
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import (
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"bytes"
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"flag"
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"fmt"
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"io"
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"io/ioutil"
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"log"
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"os"
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"os/exec"
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)
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var stdout = flag.Bool("stdout", false, "write to stdout instead of builtin.go")
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func main() {
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flag.Parse()
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var b bytes.Buffer
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fmt.Fprintln(&b, "// AUTO-GENERATED by mkbuiltin.go; DO NOT EDIT")
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fmt.Fprintln(&b, "")
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fmt.Fprintln(&b, "package gc")
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mkbuiltin(&b, "runtime")
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var err error
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if *stdout {
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_, err = os.Stdout.Write(b.Bytes())
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} else {
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err = ioutil.WriteFile("builtin.go", b.Bytes(), 0666)
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}
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if err != nil {
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log.Fatal(err)
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}
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}
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// Compile .go file, import data from .o file, and write Go string version.
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func mkbuiltin(w io.Writer, name string) {
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args := []string{"tool", "compile", "-A"}
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if name == "runtime" {
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args = append(args, "-u")
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}
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args = append(args, "builtin/"+name+".go")
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if err := exec.Command("go", args...).Run(); err != nil {
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log.Fatal(err)
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}
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obj := name + ".o"
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defer os.Remove(obj)
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b, err := ioutil.ReadFile(obj)
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if err != nil {
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log.Fatal(err)
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}
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// Look for $$B that introduces binary export data.
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i := bytes.Index(b, []byte("\n$$B\n"))
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if i < 0 {
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log.Fatal("did not find beginning of export data")
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}
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b = b[i+5:]
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// Look for $$ that closes export data.
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i = bytes.Index(b, []byte("\n$$\n"))
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if i < 0 {
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log.Fatal("did not find end of export data")
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}
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b = b[:i+4]
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// Process and reformat export data.
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const n = 40 // number of bytes per line
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fmt.Fprintf(w, "\nconst %simport = \"\"", name)
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for len(b) > 0 {
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i := len(b)
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if i > n {
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i = n
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}
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fmt.Fprintf(w, " +\n\t%q", b[:i])
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b = b[i:]
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}
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fmt.Fprintf(w, "\n")
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}
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