From: Joel Sing Date: Wed, 14 Nov 2012 15:24:14 +0000 (+1100) Subject: debug/elf: do not skip first symbol in the symbol table X-Git-Tag: go1.1rc2~1871 X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=76689845e331d32c94d77280c34fb92e7dde79ba;p=gostls13.git debug/elf: do not skip first symbol in the symbol table Do not skip the first symbol in the symbol table. Any other indexes into the symbol table (for example, indexes in relocation entries) will now refer to the symbol following the one that was intended. Add an object that contains debug relocations, which debug/dwarf failed to decode correctly. Extend the relocation tests to cover this case. Note that the existing tests passed since the symbol following the symbol that required relocation is also of type STT_SECTION. Fixes #4107. R=golang-dev, mikioh.mikioh, iant, iant CC=golang-dev https://golang.org/cl/6848044 --- diff --git a/doc/go1.1.html b/doc/go1.1.html index 6eacc1f325..3e0bd4f009 100644 --- a/doc/go1.1.html +++ b/doc/go1.1.html @@ -62,4 +62,14 @@ to adjust frame pointer offsets.

Changes to the standard library

+

debug/elf

+

+Previous versions of the debug/elf package intentionally skipped over the first +symbol in the ELF symbol table, since it is always an empty symbol. This symbol +is no longer skipped since indexes into the symbol table returned by debug/elf, +will be different to indexes into the original ELF symbol table. Any code that +calls the debug/elf functions Symbols or ImportedSymbols may need to be +adjusted to account for the additional symbol and the change in symbol offsets. +

+ TODO diff --git a/src/pkg/debug/elf/file.go b/src/pkg/debug/elf/file.go index d38da4bf8e..25b04d7959 100644 --- a/src/pkg/debug/elf/file.go +++ b/src/pkg/debug/elf/file.go @@ -417,10 +417,6 @@ func (f *File) getSymbols32(typ SectionType) ([]Symbol, []byte, error) { return nil, nil, errors.New("cannot load string table section") } - // The first entry is all zeros. - var skip [Sym32Size]byte - symtab.Read(skip[0:]) - symbols := make([]Symbol, symtab.Len()/Sym32Size) i := 0 @@ -460,10 +456,6 @@ func (f *File) getSymbols64(typ SectionType) ([]Symbol, []byte, error) { return nil, nil, errors.New("cannot load string table section") } - // The first entry is all zeros. - var skip [Sym64Size]byte - symtab.Read(skip[0:]) - symbols := make([]Symbol, symtab.Len()/Sym64Size) i := 0 diff --git a/src/pkg/debug/elf/file_test.go b/src/pkg/debug/elf/file_test.go index 12036e816b..810a2f9b9a 100644 --- a/src/pkg/debug/elf/file_test.go +++ b/src/pkg/debug/elf/file_test.go @@ -175,23 +175,41 @@ func TestOpen(t *testing.T) { } } +type relocationTestEntry struct { + entryNumber int + entry *dwarf.Entry +} + type relocationTest struct { - file string - firstEntry *dwarf.Entry + file string + entries []relocationTestEntry } var relocationTests = []relocationTest{ { "testdata/go-relocation-test-gcc441-x86-64.obj", - &dwarf.Entry{Offset: 0xb, Tag: dwarf.TagCompileUnit, Children: true, Field: []dwarf.Field{{Attr: dwarf.AttrProducer, Val: "GNU C 4.4.1"}, {Attr: dwarf.AttrLanguage, Val: int64(1)}, {Attr: dwarf.AttrName, Val: "go-relocation-test.c"}, {Attr: dwarf.AttrCompDir, Val: "/tmp"}, {Attr: dwarf.AttrLowpc, Val: uint64(0x0)}, {Attr: dwarf.AttrHighpc, Val: uint64(0x6)}, {Attr: dwarf.AttrStmtList, Val: int64(0)}}}, + []relocationTestEntry{ + {0, &dwarf.Entry{Offset: 0xb, Tag: dwarf.TagCompileUnit, Children: true, Field: []dwarf.Field{{Attr: dwarf.AttrProducer, Val: "GNU C 4.4.1"}, {Attr: dwarf.AttrLanguage, Val: int64(1)}, {Attr: dwarf.AttrName, Val: "go-relocation-test.c"}, {Attr: dwarf.AttrCompDir, Val: "/tmp"}, {Attr: dwarf.AttrLowpc, Val: uint64(0x0)}, {Attr: dwarf.AttrHighpc, Val: uint64(0x6)}, {Attr: dwarf.AttrStmtList, Val: int64(0)}}}}, + }, }, { "testdata/go-relocation-test-gcc441-x86.obj", - &dwarf.Entry{Offset: 0xb, Tag: dwarf.TagCompileUnit, Children: true, Field: []dwarf.Field{{Attr: dwarf.AttrProducer, Val: "GNU C 4.4.1"}, {Attr: dwarf.AttrLanguage, Val: int64(1)}, {Attr: dwarf.AttrName, Val: "t.c"}, {Attr: dwarf.AttrCompDir, Val: "/tmp"}, {Attr: dwarf.AttrLowpc, Val: uint64(0x0)}, {Attr: dwarf.AttrHighpc, Val: uint64(0x5)}, {Attr: dwarf.AttrStmtList, Val: int64(0)}}}, + []relocationTestEntry{ + {0, &dwarf.Entry{Offset: 0xb, Tag: dwarf.TagCompileUnit, Children: true, Field: []dwarf.Field{{Attr: dwarf.AttrProducer, Val: "GNU C 4.4.1"}, {Attr: dwarf.AttrLanguage, Val: int64(1)}, {Attr: dwarf.AttrName, Val: "t.c"}, {Attr: dwarf.AttrCompDir, Val: "/tmp"}, {Attr: dwarf.AttrLowpc, Val: uint64(0x0)}, {Attr: dwarf.AttrHighpc, Val: uint64(0x5)}, {Attr: dwarf.AttrStmtList, Val: int64(0)}}}}, + }, }, { "testdata/go-relocation-test-gcc424-x86-64.obj", - &dwarf.Entry{Offset: 0xb, Tag: dwarf.TagCompileUnit, Children: true, Field: []dwarf.Field{{Attr: dwarf.AttrProducer, Val: "GNU C 4.2.4 (Ubuntu 4.2.4-1ubuntu4)"}, {Attr: dwarf.AttrLanguage, Val: int64(1)}, {Attr: dwarf.AttrName, Val: "go-relocation-test-gcc424.c"}, {Attr: dwarf.AttrCompDir, Val: "/tmp"}, {Attr: dwarf.AttrLowpc, Val: uint64(0x0)}, {Attr: dwarf.AttrHighpc, Val: uint64(0x6)}, {Attr: dwarf.AttrStmtList, Val: int64(0)}}}, + []relocationTestEntry{ + {0, &dwarf.Entry{Offset: 0xb, Tag: dwarf.TagCompileUnit, Children: true, Field: []dwarf.Field{{Attr: dwarf.AttrProducer, Val: "GNU C 4.2.4 (Ubuntu 4.2.4-1ubuntu4)"}, {Attr: dwarf.AttrLanguage, Val: int64(1)}, {Attr: dwarf.AttrName, Val: "go-relocation-test-gcc424.c"}, {Attr: dwarf.AttrCompDir, Val: "/tmp"}, {Attr: dwarf.AttrLowpc, Val: uint64(0x0)}, {Attr: dwarf.AttrHighpc, Val: uint64(0x6)}, {Attr: dwarf.AttrStmtList, Val: int64(0)}}}}, + }, + }, + { + "testdata/gcc-amd64-openbsd-debug-with-rela.obj", + []relocationTestEntry{ + {203, &dwarf.Entry{Offset: 0xc62, Tag: dwarf.TagMember, Children: false, Field: []dwarf.Field{{Attr: dwarf.AttrName, Val: "it_interval"}, {Attr: dwarf.AttrDeclFile, Val: int64(7)}, {Attr: dwarf.AttrDeclLine, Val: int64(236)}, {Attr: dwarf.AttrType, Val: dwarf.Offset(0xb7f)}, {Attr: dwarf.AttrDataMemberLoc, Val: []byte{0x23, 0x0}}}}}, + {204, &dwarf.Entry{Offset: 0xc70, Tag: dwarf.TagMember, Children: false, Field: []dwarf.Field{{Attr: dwarf.AttrName, Val: "it_value"}, {Attr: dwarf.AttrDeclFile, Val: int64(7)}, {Attr: dwarf.AttrDeclLine, Val: int64(237)}, {Attr: dwarf.AttrType, Val: dwarf.Offset(0xb7f)}, {Attr: dwarf.AttrDataMemberLoc, Val: []byte{0x23, 0x10}}}}}, + }, }, } @@ -207,20 +225,24 @@ func TestDWARFRelocations(t *testing.T) { t.Error(err) continue } - reader := dwarf.Reader() - // Checking only the first entry is sufficient since it has - // many different strings. If the relocation had failed, all - // the string offsets would be zero and all the strings would - // end up being the same. - firstEntry, err := reader.Next() - if err != nil { - t.Error(err) - continue - } - - if !reflect.DeepEqual(test.firstEntry, firstEntry) { - t.Errorf("#%d: mismatch: got:%#v want:%#v", i, firstEntry, test.firstEntry) - continue + for _, testEntry := range test.entries { + reader := dwarf.Reader() + for j := 0; j < testEntry.entryNumber; j++ { + entry, err := reader.Next() + if entry == nil || err != nil { + t.Errorf("Failed to skip to entry %d: %v", testEntry.entryNumber, err) + continue + } + } + entry, err := reader.Next() + if err != nil { + t.Error(err) + continue + } + if !reflect.DeepEqual(testEntry.entry, entry) { + t.Errorf("#%d/%d: mismatch: got:%#v want:%#v", i, testEntry.entryNumber, entry, testEntry.entry) + continue + } } } } diff --git a/src/pkg/debug/elf/testdata/gcc-amd64-openbsd-debug-with-rela.obj b/src/pkg/debug/elf/testdata/gcc-amd64-openbsd-debug-with-rela.obj new file mode 100644 index 0000000000..f62b1ea1ca Binary files /dev/null and b/src/pkg/debug/elf/testdata/gcc-amd64-openbsd-debug-with-rela.obj differ