mirror of
https://github.com/golang/go
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e24977d231
The next CL will remove the -G flag, effectively hard-coding it to its current default (-G=3). Change-Id: Ib4743b529206928f9f1cca9fdb19989728327831 Reviewed-on: https://go-review.googlesource.com/c/go/+/388534 Reviewed-by: Keith Randall <khr@golang.org> Trust: Matthew Dempsky <mdempsky@google.com> Run-TryBot: Matthew Dempsky <mdempsky@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
76 lines
1.7 KiB
Go
76 lines
1.7 KiB
Go
// run
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// Copyright 2021 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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// Check that the compiler refuses excessively long constants.
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package main
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import (
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"bytes"
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"fmt"
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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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"path/filepath"
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"runtime"
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"strings"
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)
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// testProg creates a package called name, with path dir/name.go,
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// which declares an untyped constant of the given length.
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// testProg compiles this package and checks for the absence or
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// presence of a constant literal error.
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func testProg(dir, name string, length int, ok bool) {
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var buf bytes.Buffer
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fmt.Fprintf(&buf,
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"package %s; const _ = %s // %d digits",
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name, strings.Repeat("9", length), length,
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)
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filename := filepath.Join(dir, fmt.Sprintf("%s.go", name))
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if err := os.WriteFile(filename, buf.Bytes(), 0666); err != nil {
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log.Fatal(err)
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}
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cmd := exec.Command("go", "tool", "compile", filename)
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cmd.Dir = dir
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output, err := cmd.CombinedOutput()
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if ok {
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// no error expected
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if err != nil {
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log.Fatalf("%s: compile failed unexpectedly: %v", name, err)
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}
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return
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}
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// error expected
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if err == nil {
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log.Fatalf("%s: compile succeeded unexpectedly", name)
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}
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if !bytes.Contains(output, []byte("excessively long constant")) {
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log.Fatalf("%s: wrong compiler error message:\n%s\n", name, output)
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}
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}
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func main() {
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if runtime.GOOS == "js" || runtime.Compiler != "gc" {
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return
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}
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dir, err := ioutil.TempDir("", "const7_")
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if err != nil {
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log.Fatalf("creating temp dir: %v\n", err)
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}
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defer os.RemoveAll(dir)
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const limit = 10000 // compiler-internal constant length limit
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testProg(dir, "x1", limit, true)
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testProg(dir, "x2", limit+1, false)
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}
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