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https://github.com/golang/go
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f80b12667c
Fixes #54280. Change-Id: I44a31daaace50bc90c96cd36387bd1a009d6a287 Reviewed-on: https://go-review.googlesource.com/c/go/+/424055 Reviewed-by: Robert Findley <rfindley@google.com> Reviewed-by: Robert Griesemer <gri@google.com> Run-TryBot: Robert Griesemer <gri@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
79 lines
1.9 KiB
Go
79 lines
1.9 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, msg string) {
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var buf bytes.Buffer
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fmt.Fprintf(&buf,
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"package %s; const _ = 0b%s // %d bits",
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name, strings.Repeat("1", 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", "-p=p", filename)
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cmd.Dir = dir
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output, err := cmd.CombinedOutput()
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if msg == "" {
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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(msg)) {
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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 bitLimit = 512
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const charLimit = 10000 // compiler-internal constant length limit
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testProg(dir, "x1", bitLimit, "")
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testProg(dir, "x2", bitLimit+1, "constant overflow")
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testProg(dir, "x3", charLimit-2, "constant overflow") // -2 because literal contains 0b prefix
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testProg(dir, "x4", charLimit-1, "excessively long constant")
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}
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