issue33555.go

     1  // run
     2  
     3  //go:build !nacl && !js && !wasip1 && !gccgo
     4  
     5  // Copyright 2019 The Go Authors. All rights reserved.
     6  // Use of this source code is governed by a BSD-style
     7  // license that can be found in the LICENSE file.
     8  
     9  // Test that the linker permits long call sequences.
    10  package main
    11  
    12  import (
    13  	"bytes"
    14  	"fmt"
    15  	"io/ioutil"
    16  	"os"
    17  	"os/exec"
    18  	"path/filepath"
    19  	"strconv"
    20  )
    21  
    22  const start = `
    23  package main
    24  
    25  func main() {
    26  	println(f0() + 1)
    27  }
    28  `
    29  
    30  const fn = `
    31  //go:noinline
    32  func f%d() int {
    33  	return f%d() + 1
    34  }`
    35  
    36  const fnlast = `
    37  //go:noinline
    38  func f%d() int {
    39  	return 0
    40  }
    41  `
    42  
    43  const count = 400
    44  
    45  func main() {
    46  	if err := test(); err != nil {
    47  		fmt.Fprintln(os.Stderr, err)
    48  		os.Exit(1)
    49  	}
    50  }
    51  
    52  func test() error {
    53  	var buf bytes.Buffer
    54  	buf.WriteString(start)
    55  	for i := 0; i < count; i++ {
    56  		fmt.Fprintf(&buf, fn, i, i + 1)
    57  	}
    58  	fmt.Fprintf(&buf, fnlast, count)
    59  
    60  	dir, err := ioutil.TempDir("", "issue33555")
    61  	if err != nil {
    62  		return err
    63  	}
    64  	defer os.RemoveAll(dir)
    65  
    66  	fn := filepath.Join(dir, "x.go")
    67  	if err := ioutil.WriteFile(fn, buf.Bytes(), 0644); err != nil {
    68  		return err
    69  	}
    70  
    71  	out, err := exec.Command("go", "run", fn).CombinedOutput()
    72  	if err != nil {
    73  		return err
    74  	}
    75  
    76  	want := strconv.Itoa(count + 1)
    77  	if got := string(bytes.TrimSpace(out)); got != want {
    78  		return fmt.Errorf("got %q want %q", got, want)
    79  	}
    80  
    81  	return nil
    82  }
    83
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