1 files changed, 123 insertions, 0 deletions
diff --git a/src/cmd/internal/obj/objfile_test.go b/src/cmd/internal/obj/objfile_test.go
new file mode 100644
index 0000000..146627b
--- /dev/null
+++ b/src/cmd/internal/obj/objfile_test.go
@@ -0,0 +1,123 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package obj
+
+import (
+	"bytes"
+	"cmd/internal/goobj"
+	"cmd/internal/sys"
+	"internal/testenv"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"testing"
+	"unsafe"
+)
+
+var dummyArch = LinkArch{Arch: sys.ArchAMD64}
+
+func TestContentHash64(t *testing.T) {
+	s1 := &LSym{P: []byte("A")}
+	s2 := &LSym{P: []byte("A\x00\x00\x00")}
+	s1.Set(AttrContentAddressable, true)
+	s2.Set(AttrContentAddressable, true)
+	h1 := contentHash64(s1)
+	h2 := contentHash64(s2)
+	if h1 != h2 {
+		t.Errorf("contentHash64(s1)=%x, contentHash64(s2)=%x, expect equal", h1, h2)
+	}
+
+	ctxt := Linknew(&dummyArch) // little endian
+	s3 := ctxt.Int64Sym(int64('A'))
+	h3 := contentHash64(s3)
+	if h1 != h3 {
+		t.Errorf("contentHash64(s1)=%x, contentHash64(s3)=%x, expect equal", h1, h3)
+	}
+}
+
+func TestContentHash(t *testing.T) {
+	syms := []*LSym{
+		&LSym{P: []byte("TestSymbol")},  // 0
+		&LSym{P: []byte("TestSymbol")},  // 1
+		&LSym{P: []byte("TestSymbol2")}, // 2
+		&LSym{P: []byte("")},            // 3
+		&LSym{P: []byte("")},            // 4
+		&LSym{P: []byte("")},            // 5
+		&LSym{P: []byte("")},            // 6
+	}
+	for _, s := range syms {
+		s.Set(AttrContentAddressable, true)
+		s.PkgIdx = goobj.PkgIdxHashed
+	}
+	// s3 references s0
+	r := Addrel(syms[3])
+	r.Sym = syms[0]
+	// s4 references s0
+	r = Addrel(syms[4])
+	r.Sym = syms[0]
+	// s5 references s1
+	r = Addrel(syms[5])
+	r.Sym = syms[1]
+	// s6 references s2
+	r = Addrel(syms[6])
+	r.Sym = syms[2]
+
+	// compute hashes
+	h := make([]goobj.HashType, len(syms))
+	w := &writer{}
+	for i := range h {
+		h[i] = w.contentHash(syms[i])
+	}
+
+	tests := []struct {
+		a, b  int
+		equal bool
+	}{
+		{0, 1, true},  // same contents, no relocs
+		{0, 2, false}, // different contents
+		{3, 4, true},  // same contents, same relocs
+		{3, 5, true},  // recursively same contents
+		{3, 6, false}, // same contents, different relocs
+	}
+	for _, test := range tests {
+		if (h[test.a] == h[test.b]) != test.equal {
+			eq := "equal"
+			if !test.equal {
+				eq = "not equal"
+			}
+			t.Errorf("h%d=%x, h%d=%x, expect %s", test.a, h[test.a], test.b, h[test.b], eq)
+		}
+	}
+}
+
+func TestSymbolTooLarge(t *testing.T) { // Issue 42054
+	testenv.MustHaveGoBuild(t)
+	if unsafe.Sizeof(uintptr(0)) < 8 {
+		t.Skip("skip on 32-bit architectures")
+	}
+
+	tmpdir, err := ioutil.TempDir("", "TestSymbolTooLarge")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(tmpdir)
+
+	src := filepath.Join(tmpdir, "p.go")
+	err = ioutil.WriteFile(src, []byte("package p; var x [1<<32]byte"), 0666)
+	if err != nil {
+		t.Fatalf("failed to write source file: %v\n", err)
+	}
+	obj := filepath.Join(tmpdir, "p.o")
+	cmd := exec.Command(testenv.GoToolPath(t), "tool", "compile", "-o", obj, src)
+	out, err := cmd.CombinedOutput()
+	if err == nil {
+		t.Fatalf("did not fail\noutput: %s", out)
+	}
+	const want = "symbol too large"
+	if !bytes.Contains(out, []byte(want)) {
+		t.Errorf("unexpected error message: want: %q, got: %s", want, out)
+	}
+}