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cmd/link/internal/ld: remove C style gotos from ldelf

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ld.ldelf contained a mixture of normal and C style, goto bad, error
handling. The use of goto requires many variables to be declared well
before their use which inhibited further refactoring to this method.

This CL removes the gotos in this function. Future CLs will address
remainder of the C style function scoped declarations in this function.

Change-Id: Ib9def495209a2f8deb11dcf30ee954bca95390c6
Reviewed-on: https://go-review.googlesource.com/41172
Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This commit is contained in:
Dave Cheney 2017-04-20 10:45:01 +10:00
parent 1db0aae370
commit d728be70f4
1 changed files with 47 additions and 38 deletions
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85
src/cmd/link/internal/ld/ldelf.go
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@ -453,7 +453,6 @@ func ldelf(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) {
var add uint64 var add uint64
var e binary.ByteOrder var e binary.ByteOrder
var elfobj *ElfObj var elfobj *ElfObj
var err error
var flag int var flag int
var hdr *ElfHdrBytes var hdr *ElfHdrBytes
var hdrbuf [64]uint8 var hdrbuf [64]uint8
@ -472,12 +471,14 @@ func ldelf(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) {
var sym ElfSym var sym ElfSym
var symbols []*Symbol var symbols []*Symbol
if _, err := io.ReadFull(f, hdrbuf[:]); err != nil { if _, err := io.ReadFull(f, hdrbuf[:]); err != nil {
goto bad Errorf(nil, "%s: malformed elf file: %v", pn, err)
return
} }
hdr = new(ElfHdrBytes) hdr = new(ElfHdrBytes)
binary.Read(bytes.NewReader(hdrbuf[:]), binary.BigEndian, hdr) // only byte arrays; byte order doesn't matter binary.Read(bytes.NewReader(hdrbuf[:]), binary.BigEndian, hdr) // only byte arrays; byte order doesn't matter
if string(hdr.Ident[:4]) != "\x7FELF" { if string(hdr.Ident[:4]) != "\x7FELF" {
goto bad Errorf(nil, "%s: malformed elf file", pn)
return
} }
switch hdr.Ident[5] { switch hdr.Ident[5] {
case ElfDataLsb: case ElfDataLsb:
@ -487,7 +488,8 @@ func ldelf(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) {
e = binary.BigEndian e = binary.BigEndian
default: default:
goto bad Errorf(nil, "%s: malformed elf file", pn)
return
} }
// read header // read header
@ -534,8 +536,9 @@ func ldelf(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) {
elfobj.is64 = is64 elfobj.is64 = is64
if uint32(hdr.Ident[6]) != elfobj.version { if v := uint32(hdr.Ident[6]); v != elfobj.version {
goto bad Errorf(nil, "%s: malformed elf version: got %d, want %d", pn, v, elfobj.version)
return
} }
if e.Uint16(hdr.Type[:]) != ElfTypeRelocatable { if e.Uint16(hdr.Type[:]) != ElfTypeRelocatable {
@ -603,14 +606,16 @@ func ldelf(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) {
elfobj.nsect = uint(elfobj.shnum) elfobj.nsect = uint(elfobj.shnum)
for i := 0; uint(i) < elfobj.nsect; i++ { for i := 0; uint(i) < elfobj.nsect; i++ {
if f.Seek(int64(uint64(base)+elfobj.shoff+uint64(int64(i)*int64(elfobj.shentsize))), 0) < 0 { if f.Seek(int64(uint64(base)+elfobj.shoff+uint64(int64(i)*int64(elfobj.shentsize))), 0) < 0 {
goto bad Errorf(nil, "%s: malformed elf file", pn)
return
} }
sect = &elfobj.sect[i] sect = &elfobj.sect[i]
if is64 != 0 { if is64 != 0 {
var b ElfSectBytes64 var b ElfSectBytes64
if err = binary.Read(f, e, &b); err != nil { if err := binary.Read(f, e, &b); err != nil {
goto bad Errorf(nil, "%s: malformed elf file: %v", pn, err)
return
} }
sect.nameoff = e.Uint32(b.Name[:]) sect.nameoff = e.Uint32(b.Name[:])
@ -626,8 +631,9 @@ func ldelf(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) {
} else { } else {
var b ElfSectBytes var b ElfSectBytes
if err = binary.Read(f, e, &b); err != nil { if err := binary.Read(f, e, &b); err != nil {
goto bad Errorf(nil, "%s: malformed elf file: %v", pn, err)
return
} }
sect.nameoff = e.Uint32(b.Name[:]) sect.nameoff = e.Uint32(b.Name[:])
@ -645,13 +651,14 @@ func ldelf(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) {
// read section string table and translate names // read section string table and translate names
if elfobj.shstrndx >= uint32(elfobj.nsect) { if elfobj.shstrndx >= uint32(elfobj.nsect) {
err = fmt.Errorf("shstrndx out of range %d >= %d", elfobj.shstrndx, elfobj.nsect) Errorf(nil, "%s: malformed elf file: shstrndx out of range %d >= %d", pn, elfobj.shstrndx, elfobj.nsect)
goto bad return
} }
sect = &elfobj.sect[elfobj.shstrndx] sect = &elfobj.sect[elfobj.shstrndx]
if err = elfmap(elfobj, sect); err != nil { if err := elfmap(elfobj, sect); err != nil {
goto bad Errorf(nil, "%s: malformed elf file: %v", pn, err)
return
} }
for i := 0; uint(i) < elfobj.nsect; i++ { for i := 0; uint(i) < elfobj.nsect; i++ {
if elfobj.sect[i].nameoff != 0 { if elfobj.sect[i].nameoff != 0 {
@ -679,11 +686,13 @@ func ldelf(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) {
elfobj.nsymtab = int(elfobj.symtab.size / ELF32SYMSIZE) elfobj.nsymtab = int(elfobj.symtab.size / ELF32SYMSIZE)
} }
if err = elfmap(elfobj, elfobj.symtab); err != nil { if err := elfmap(elfobj, elfobj.symtab); err != nil {
goto bad Errorf(nil, "%s: malformed elf file: %v", pn, err)
return
} }
if err = elfmap(elfobj, elfobj.symstr); err != nil { if err := elfmap(elfobj, elfobj.symstr); err != nil {
goto bad Errorf(nil, "%s: malformed elf file: %v", pn, err)
return
} }
// load text and data segments into memory. // load text and data segments into memory.
@ -695,8 +704,9 @@ func ldelf(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) {
for i := 0; uint(i) < elfobj.nsect; i++ { for i := 0; uint(i) < elfobj.nsect; i++ {
sect = &elfobj.sect[i] sect = &elfobj.sect[i]
if sect.type_ == SHT_ARM_ATTRIBUTES && sect.name == ".ARM.attributes" { if sect.type_ == SHT_ARM_ATTRIBUTES && sect.name == ".ARM.attributes" {
if err = elfmap(elfobj, sect); err != nil { if err := elfmap(elfobj, sect); err != nil {
goto bad Errorf(nil, "%s: malformed elf file: %v", pn, err)
return
} }
parseArmAttributes(ctxt, e, sect.base[:sect.size]) parseArmAttributes(ctxt, e, sect.base[:sect.size])
} }
@ -704,8 +714,9 @@ func ldelf(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) {
continue continue
} }
if sect.type_ != ElfSectNobits { if sect.type_ != ElfSectNobits {
if err = elfmap(elfobj, sect); err != nil { if err := elfmap(elfobj, sect); err != nil {
goto bad Errorf(nil, "%s: malformed elf file: %v", pn, err)
return
} }
} }
@ -714,8 +725,8 @@ func ldelf(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) {
switch int(sect.flags) & (ElfSectFlagAlloc | ElfSectFlagWrite | ElfSectFlagExec) { switch int(sect.flags) & (ElfSectFlagAlloc | ElfSectFlagWrite | ElfSectFlagExec) {
default: default:
err = fmt.Errorf("unexpected flags for ELF section %s", sect.name) Errorf(nil, "%s: unexpected flags for ELF section %s", pn, sect.name)
goto bad return
case ElfSectFlagAlloc: case ElfSectFlagAlloc:
s.Type = objabi.SRODATA s.Type = objabi.SRODATA
@ -749,8 +760,9 @@ func ldelf(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) {
symbols = make([]*Symbol, elfobj.nsymtab) symbols = make([]*Symbol, elfobj.nsymtab)
for i := 1; i < elfobj.nsymtab; i++ { for i := 1; i < elfobj.nsymtab; i++ {
if err = readelfsym(ctxt, elfobj, i, &sym, 1, localSymVersion); err != nil { if err := readelfsym(ctxt, elfobj, i, &sym, 1, localSymVersion); err != nil {
goto bad Errorf(nil, "%s: malformed elf file: %v", pn, err)
return
} }
symbols[i] = sym.sym symbols[i] = sym.sym
if sym.type_ != ElfSymTypeFunc && sym.type_ != ElfSymTypeObject && sym.type_ != ElfSymTypeNone && sym.type_ != ElfSymTypeCommon { if sym.type_ != ElfSymTypeFunc && sym.type_ != ElfSymTypeObject && sym.type_ != ElfSymTypeNone && sym.type_ != ElfSymTypeCommon {
@ -864,8 +876,9 @@ func ldelf(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) {
continue continue
} }
sect = &elfobj.sect[rsect.info] sect = &elfobj.sect[rsect.info]
if err = elfmap(elfobj, rsect); err != nil { if err := elfmap(elfobj, rsect); err != nil {
goto bad Errorf(nil, "%s: malformed elf file: %v", pn, err)
return
} }
rela = 0 rela = 0
if rsect.type_ == ElfSectRela { if rsect.type_ == ElfSectRela {
@ -911,13 +924,14 @@ func ldelf(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) {
if info>>32 == 0 { // absolute relocation, don't bother reading the null symbol if info>>32 == 0 { // absolute relocation, don't bother reading the null symbol
rp.Sym = nil rp.Sym = nil
} else { } else {
if err = readelfsym(ctxt, elfobj, int(info>>32), &sym, 0, 0); err != nil { if err := readelfsym(ctxt, elfobj, int(info>>32), &sym, 0, 0); err != nil {
goto bad Errorf(nil, "%s: malformed elf file: %v", pn, err)
return
} }
sym.sym = symbols[info>>32] sym.sym = symbols[info>>32]
if sym.sym == nil { if sym.sym == nil {
err = fmt.Errorf("%s#%d: reloc of invalid sym #%d %s shndx=%d type=%d", sect.sym.Name, j, int(info>>32), sym.name, sym.shndx, sym.type_) Errorf(nil, "%s: malformed elf file: %s#%d: reloc of invalid sym #%d %s shndx=%d type=%d", pn, sect.sym.Name, j, int(info>>32), sym.name, sym.shndx, sym.type_)
goto bad return
} }
rp.Sym = sym.sym rp.Sym = sym.sym
@ -954,11 +968,6 @@ func ldelf(ctxt *Link, f *bio.Reader, pkg string, length int64, pn string) {
s.R = r s.R = r
s.R = s.R[:n] s.R = s.R[:n]
} }
return
bad:
Errorf(nil, "%s: malformed elf file: %v", pn, err)
} }
func section(elfobj *ElfObj, name string) *ElfSect { func section(elfobj *ElfObj, name string) *ElfSect {