link_test.go

     1  // Copyright 2020 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package tls
     6  
     7  import (
     8  	"bytes"
     9  	"internal/testenv"
    10  	"os"
    11  	"path/filepath"
    12  	"testing"
    13  )
    14  
    15  // Tests that the linker is able to remove references to the Client or Server if unused.
    16  func TestLinkerGC(t *testing.T) {
    17  	if testing.Short() {
    18  		t.Skip("skipping in short mode")
    19  	}
    20  	t.Parallel()
    21  
    22  	tests := []struct {
    23  		name    string
    24  		program string
    25  		want    []string
    26  		bad     []string
    27  	}{
    28  		{
    29  			name: "empty_import",
    30  			program: `package main
    31  import _ "crypto/tls"
    32  func main() {}
    33  `,
    34  			bad: []string{
    35  				"tls.(*Conn)",
    36  				"type:crypto/tls.clientHandshakeState",
    37  				"type:crypto/tls.serverHandshakeState",
    38  			},
    39  		},
    40  		{
    41  			name: "client_and_server",
    42  			program: `package main
    43  import "crypto/tls"
    44  func main() {
    45    tls.Dial("", "", nil)
    46    tls.Server(nil, nil)
    47  }
    48  `,
    49  			want: []string{
    50  				"crypto/tls.(*Conn).clientHandshake",
    51  				"crypto/tls.(*Conn).serverHandshake",
    52  			},
    53  		},
    54  		{
    55  			name: "only_client",
    56  			program: `package main
    57  import "crypto/tls"
    58  func main() { tls.Dial("", "", nil) }
    59  `,
    60  			want: []string{
    61  				"crypto/tls.(*Conn).clientHandshake",
    62  			},
    63  			bad: []string{
    64  				"crypto/tls.(*Conn).serverHandshake",
    65  			},
    66  		},
    67  		// TODO: add only_server like func main() { tls.Server(nil, nil) }
    68  		// That currently brings in the client via Conn.handleRenegotiation.
    69  
    70  	}
    71  	tmpDir := t.TempDir()
    72  	goFile := filepath.Join(tmpDir, "x.go")
    73  	exeFile := filepath.Join(tmpDir, "x.exe")
    74  	for _, tt := range tests {
    75  		t.Run(tt.name, func(t *testing.T) {
    76  			if err := os.WriteFile(goFile, []byte(tt.program), 0644); err != nil {
    77  				t.Fatal(err)
    78  			}
    79  			os.Remove(exeFile)
    80  			cmd := testenv.Command(t, testenv.GoToolPath(t), "build", "-o", "x.exe", "x.go")
    81  			cmd.Dir = tmpDir
    82  			if out, err := cmd.CombinedOutput(); err != nil {
    83  				t.Fatalf("compile: %v\n%s", err, out)
    84  			}
    85  
    86  			cmd = testenv.Command(t, testenv.GoToolPath(t), "tool", "nm", "x.exe")
    87  			cmd.Dir = tmpDir
    88  			nm, err := testenv.CleanCmdEnv(cmd).CombinedOutput()
    89  			if err != nil {
    90  				t.Fatalf("nm: %v\n%s", err, nm)
    91  			}
    92  			for _, sym := range tt.want {
    93  				if !bytes.Contains(nm, []byte(sym)) {
    94  					t.Errorf("expected symbol %q not found", sym)
    95  				}
    96  			}
    97  			for _, sym := range tt.bad {
    98  				if bytes.Contains(nm, []byte(sym)) {
    99  					t.Errorf("unexpected symbol %q found", sym)
   100  				}
   101  			}
   102  		})
   103  	}
   104  }
   105
View as plain text