From 20819440fc65d28fabe8f7410ea8fe193cdc53c6 Mon Sep 17 00:00:00 2001 From: Cherry Zhang Date: Thu, 15 Oct 2020 18:04:08 -0400 Subject: [PATCH] cmd/internal/objfile: correct file table reading for Go object file Apparently I never actually understood the new file table in Go object files. The PC value stream actually encodes the file index in the per-CU table. I thought it was indexing into a per-function table, which then contains index to the per-CU table. Remove the extra indirection. Change-Id: I0aea5629f7b3888ebe3a04fea437aa15ce89519e Reviewed-on: https://go-review.googlesource.com/c/go/+/262779 Trust: Cherry Zhang Run-TryBot: Cherry Zhang TryBot-Result: Go Bot Reviewed-by: Than McIntosh Reviewed-by: Jeremy Faller --- src/cmd/internal/objfile/goobj.go | 4 +-- src/cmd/objdump/objdump_test.go | 38 +++++++++++++++++++++ src/cmd/objdump/testdata/testfilenum/a.go | 7 ++++ src/cmd/objdump/testdata/testfilenum/b.go | 7 ++++ src/cmd/objdump/testdata/testfilenum/c.go | 7 ++++ src/cmd/objdump/testdata/testfilenum/go.mod | 3 ++ 6 files changed, 63 insertions(+), 3 deletions(-) create mode 100644 src/cmd/objdump/testdata/testfilenum/a.go create mode 100644 src/cmd/objdump/testdata/testfilenum/b.go create mode 100644 src/cmd/objdump/testdata/testfilenum/c.go create mode 100644 src/cmd/objdump/testdata/testfilenum/go.mod diff --git a/src/cmd/internal/objfile/goobj.go b/src/cmd/internal/objfile/goobj.go index 7f74a8256c..f19bec5dcb 100644 --- a/src/cmd/internal/objfile/goobj.go +++ b/src/cmd/internal/objfile/goobj.go @@ -267,13 +267,11 @@ func (f *goobjFile) PCToLine(pc uint64) (string, int, *gosym.Func) { } b := r.BytesAt(r.DataOff(isym), r.DataSize(isym)) var info *goobj.FuncInfo - lengths := info.ReadFuncInfoLengths(b) pcline := getSymData(info.ReadPcline(b)) line := int(pcValue(pcline, pc-addr, f.arch)) pcfile := getSymData(info.ReadPcfile(b)) fileID := pcValue(pcfile, pc-addr, f.arch) - globalFileID := info.ReadFile(b, lengths.FileOff, uint32(fileID)) - fileName := r.File(int(globalFileID)) + fileName := r.File(int(fileID)) // Note: we provide only the name in the Func structure. // We could provide more if needed. return fileName, line, &gosym.Func{Sym: &gosym.Sym{Name: osym.Name(r)}} diff --git a/src/cmd/objdump/objdump_test.go b/src/cmd/objdump/objdump_test.go index 85d1a2efb0..d136e2e6c3 100644 --- a/src/cmd/objdump/objdump_test.go +++ b/src/cmd/objdump/objdump_test.go @@ -333,3 +333,41 @@ func TestDisasmGoobj(t *testing.T) { t.Logf("full disassembly:\n%s", text) } } + +func TestGoobjFileNumber(t *testing.T) { + // Test that file table in Go object file is parsed correctly. + testenv.MustHaveGoBuild(t) + + t.Parallel() + + tmpdir, err := ioutil.TempDir("", "TestGoobjFileNumber") + if err != nil { + t.Fatal(err) + } + defer os.RemoveAll(tmpdir) + + obj := filepath.Join(tmpdir, "p.a") + cmd := exec.Command(testenv.GoToolPath(t), "build", "-o", obj) + cmd.Dir = filepath.Join("testdata/testfilenum") + out, err := cmd.CombinedOutput() + if err != nil { + t.Fatalf("build failed: %v\n%s", err, out) + } + + cmd = exec.Command(exe, obj) + out, err = cmd.CombinedOutput() + if err != nil { + t.Fatalf("objdump failed: %v\n%s", err, out) + } + + text := string(out) + for _, s := range []string{"a.go", "b.go", "c.go"} { + if !strings.Contains(text, s) { + t.Errorf("output missing '%s'", s) + } + } + + if t.Failed() { + t.Logf("output:\n%s", text) + } +} diff --git a/src/cmd/objdump/testdata/testfilenum/a.go b/src/cmd/objdump/testdata/testfilenum/a.go new file mode 100644 index 0000000000..2729ae0abf --- /dev/null +++ b/src/cmd/objdump/testdata/testfilenum/a.go @@ -0,0 +1,7 @@ +// 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 p + +func A() {} diff --git a/src/cmd/objdump/testdata/testfilenum/b.go b/src/cmd/objdump/testdata/testfilenum/b.go new file mode 100644 index 0000000000..a632aafe7b --- /dev/null +++ b/src/cmd/objdump/testdata/testfilenum/b.go @@ -0,0 +1,7 @@ +// 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 p + +func B() {} diff --git a/src/cmd/objdump/testdata/testfilenum/c.go b/src/cmd/objdump/testdata/testfilenum/c.go new file mode 100644 index 0000000000..d73efa7315 --- /dev/null +++ b/src/cmd/objdump/testdata/testfilenum/c.go @@ -0,0 +1,7 @@ +// 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 p + +func C() {} diff --git a/src/cmd/objdump/testdata/testfilenum/go.mod b/src/cmd/objdump/testdata/testfilenum/go.mod new file mode 100644 index 0000000000..db432883a9 --- /dev/null +++ b/src/cmd/objdump/testdata/testfilenum/go.mod @@ -0,0 +1,3 @@ +module objdumptest + +go 1.16 -- 2.48.1