outbuf_test.go

Documentation: cmd/link/internal/ld

     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 ld
     6  
     7  import (
     8  	"path/filepath"
     9  	"runtime"
    10  	"testing"
    11  )
    12  
    13  // TestMMap ensures that we can actually mmap on every supported platform.
    14  func TestMMap(t *testing.T) {
    15  	switch runtime.GOOS {
    16  	default:
    17  		t.Skip("unsupported OS")
    18  	case "aix", "darwin", "ios", "dragonfly", "freebsd", "linux", "netbsd", "openbsd", "windows":
    19  	}
    20  	dir := t.TempDir()
    21  	filename := filepath.Join(dir, "foo.out")
    22  	ob := NewOutBuf(nil)
    23  	if err := ob.Open(filename); err != nil {
    24  		t.Fatalf("error opening file: %v", err)
    25  	}
    26  	defer ob.Close()
    27  	if err := ob.Mmap(1 << 20); err != nil {
    28  		t.Errorf("error mmapping file %v", err)
    29  	}
    30  	if !ob.isMmapped() {
    31  		t.Errorf("should be mmapped")
    32  	}
    33  }
    34  
    35  // TestWriteLoc ensures that the math surrounding writeLoc is correct.
    36  func TestWriteLoc(t *testing.T) {
    37  	tests := []struct {
    38  		bufLen          int
    39  		off             int64
    40  		heapLen         int
    41  		lenToWrite      int64
    42  		expectedHeapLen int
    43  		writePos        int64
    44  		addressInHeap   bool
    45  	}{
    46  		{100, 0, 0, 100, 0, 0, false},
    47  		{100, 100, 0, 100, 100, 0, true},
    48  		{10, 10, 0, 100, 100, 0, true},
    49  		{10, 20, 10, 100, 110, 10, true},
    50  		{0, 0, 0, 100, 100, 0, true},
    51  	}
    52  
    53  	for i, test := range tests {
    54  		ob := &OutBuf{
    55  			buf:  make([]byte, test.bufLen),
    56  			off:  test.off,
    57  			heap: make([]byte, test.heapLen),
    58  		}
    59  		pos, buf := ob.writeLoc(test.lenToWrite)
    60  		if pos != test.writePos {
    61  			t.Errorf("[%d] position = %d, expected %d", i, pos, test.writePos)
    62  		}
    63  		message := "mmapped area"
    64  		expected := ob.buf
    65  		if test.addressInHeap {
    66  			message = "heap"
    67  			expected = ob.heap
    68  		}
    69  		if &buf[0] != &expected[0] {
    70  			t.Errorf("[%d] expected position to be %q", i, message)
    71  		}
    72  		if len(ob.heap) != test.expectedHeapLen {
    73  			t.Errorf("[%d] expected len(ob.heap) == %d, got %d", i, test.expectedHeapLen, len(ob.heap))
    74  		}
    75  	}
    76  }
    77  
    78  func TestIsMmapped(t *testing.T) {
    79  	tests := []struct {
    80  		length   int
    81  		expected bool
    82  	}{
    83  		{0, false},
    84  		{1, true},
    85  	}
    86  	for i, test := range tests {
    87  		ob := &OutBuf{buf: make([]byte, test.length)}
    88  		if v := ob.isMmapped(); v != test.expected {
    89  
    90  			t.Errorf("[%d] isMmapped == %t, expected %t", i, v, test.expected)
    91  		}
    92  	}
    93  }
    94
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