From f901ea701ddac5a4d600d49007e54caa32b4c9b5 Mon Sep 17 00:00:00 2001 From: Cherry Zhang Date: Sun, 8 Nov 2020 11:27:53 -0500 Subject: cmd/internal/goobj: store relocation type as uint16 Currently, relocation type is stored as uint8 in object files, as Go relocations do not exceed 255. In the linker, however, it is used as a 16-bit type, because external relocations can exceed 255. The linker has to store the extra byte in a side table. This complicates many things. Just store it as uint16 in object files. This simplifies things, with a small cost of increasing the object file sizes. before after hello.o 1672 1678 runtime.a 7927784 8056194 Change-Id: I313cf44ad0b8b3b76e35055ae55d911ff35e3158 Reviewed-on: https://go-review.googlesource.com/c/go/+/268477 Trust: Cherry Zhang Run-TryBot: Cherry Zhang TryBot-Result: Go Bot Reviewed-by: Than McIntosh --- src/cmd/internal/goobj/objfile.go | 34 +++++++++++++++++----------------- src/cmd/internal/goobj/objfile_test.go | 4 ++-- src/cmd/internal/obj/objfile.go | 2 +- 3 files changed, 20 insertions(+), 20 deletions(-) (limited to 'src/cmd/internal') diff --git a/src/cmd/internal/goobj/objfile.go b/src/cmd/internal/goobj/objfile.go index 247cc695f0..e2858bd57d 100644 --- a/src/cmd/internal/goobj/objfile.go +++ b/src/cmd/internal/goobj/objfile.go @@ -33,7 +33,7 @@ import ( // New object file format. // // Header struct { -// Magic [...]byte // "\x00go116ld" +// Magic [...]byte // "\x00go117ld" // Fingerprint [8]byte // Flags uint32 // Offsets [...]uint32 // byte offset of each block below @@ -89,7 +89,7 @@ import ( // Relocs [...]struct { // Off int32 // Size uint8 -// Type uint8 +// Type uint16 // Add int64 // Sym symRef // } @@ -219,7 +219,7 @@ type Header struct { Offsets [NBlk]uint32 } -const Magic = "\x00go116ld" +const Magic = "\x00go117ld" func (h *Header) Write(w *Writer) { w.RawString(h.Magic) @@ -373,32 +373,32 @@ const HashSize = sha1.Size // Reloc struct { // Off int32 // Siz uint8 -// Type uint8 +// Type uint16 // Add int64 // Sym SymRef // } type Reloc [RelocSize]byte -const RelocSize = 4 + 1 + 1 + 8 + 8 +const RelocSize = 4 + 1 + 2 + 8 + 8 -func (r *Reloc) Off() int32 { return int32(binary.LittleEndian.Uint32(r[:])) } -func (r *Reloc) Siz() uint8 { return r[4] } -func (r *Reloc) Type() uint8 { return r[5] } -func (r *Reloc) Add() int64 { return int64(binary.LittleEndian.Uint64(r[6:])) } +func (r *Reloc) Off() int32 { return int32(binary.LittleEndian.Uint32(r[:])) } +func (r *Reloc) Siz() uint8 { return r[4] } +func (r *Reloc) Type() uint16 { return binary.LittleEndian.Uint16(r[5:]) } +func (r *Reloc) Add() int64 { return int64(binary.LittleEndian.Uint64(r[7:])) } func (r *Reloc) Sym() SymRef { - return SymRef{binary.LittleEndian.Uint32(r[14:]), binary.LittleEndian.Uint32(r[18:])} + return SymRef{binary.LittleEndian.Uint32(r[15:]), binary.LittleEndian.Uint32(r[19:])} } -func (r *Reloc) SetOff(x int32) { binary.LittleEndian.PutUint32(r[:], uint32(x)) } -func (r *Reloc) SetSiz(x uint8) { r[4] = x } -func (r *Reloc) SetType(x uint8) { r[5] = x } -func (r *Reloc) SetAdd(x int64) { binary.LittleEndian.PutUint64(r[6:], uint64(x)) } +func (r *Reloc) SetOff(x int32) { binary.LittleEndian.PutUint32(r[:], uint32(x)) } +func (r *Reloc) SetSiz(x uint8) { r[4] = x } +func (r *Reloc) SetType(x uint16) { binary.LittleEndian.PutUint16(r[5:], x) } +func (r *Reloc) SetAdd(x int64) { binary.LittleEndian.PutUint64(r[7:], uint64(x)) } func (r *Reloc) SetSym(x SymRef) { - binary.LittleEndian.PutUint32(r[14:], x.PkgIdx) - binary.LittleEndian.PutUint32(r[18:], x.SymIdx) + binary.LittleEndian.PutUint32(r[15:], x.PkgIdx) + binary.LittleEndian.PutUint32(r[19:], x.SymIdx) } -func (r *Reloc) Set(off int32, size uint8, typ uint8, add int64, sym SymRef) { +func (r *Reloc) Set(off int32, size uint8, typ uint16, add int64, sym SymRef) { r.SetOff(off) r.SetSiz(size) r.SetType(typ) diff --git a/src/cmd/internal/goobj/objfile_test.go b/src/cmd/internal/goobj/objfile_test.go index 99d02a1bf1..ad80ede0f3 100644 --- a/src/cmd/internal/goobj/objfile_test.go +++ b/src/cmd/internal/goobj/objfile_test.go @@ -40,7 +40,7 @@ func TestReadWrite(t *testing.T) { var r Reloc r.SetOff(12) r.SetSiz(4) - r.SetType(uint8(objabi.R_ADDR)) + r.SetType(uint16(objabi.R_ADDR)) r.SetAdd(54321) r.SetSym(SymRef{11, 22}) r.Write(w) @@ -63,7 +63,7 @@ func TestReadWrite(t *testing.T) { b = b[SymSize:] var r2 Reloc r2.fromBytes(b) - if r2.Off() != 12 || r2.Siz() != 4 || r2.Type() != uint8(objabi.R_ADDR) || r2.Add() != 54321 || r2.Sym() != (SymRef{11, 22}) { + if r2.Off() != 12 || r2.Siz() != 4 || r2.Type() != uint16(objabi.R_ADDR) || r2.Add() != 54321 || r2.Sym() != (SymRef{11, 22}) { t.Errorf("read Reloc2 mismatch: got %v %v %v %v %v", r2.Off(), r2.Siz(), r2.Type(), r2.Add(), r2.Sym()) } diff --git a/src/cmd/internal/obj/objfile.go b/src/cmd/internal/obj/objfile.go index b031afbc36..24fb5a19de 100644 --- a/src/cmd/internal/obj/objfile.go +++ b/src/cmd/internal/obj/objfile.go @@ -498,7 +498,7 @@ func (w *writer) Reloc(r *Reloc) { var o goobj.Reloc o.SetOff(r.Off) o.SetSiz(r.Siz) - o.SetType(uint8(r.Type)) + o.SetType(uint16(r.Type)) o.SetAdd(r.Add) o.SetSym(makeSymRef(r.Sym)) o.Write(w.Writer) -- cgit v1.3-5-g9baa