/
decodesym.go
187 lines (155 loc) · 5.3 KB
/
decodesym.go
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// Copyright 2012 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 ld
import "cmd/internal/obj"
// Decoding the type.* symbols. This has to be in sync with
// ../../runtime/type.go, or more specifically, with what
// ../gc/reflect.c stuffs in these.
func decode_reloc(s *LSym, off int32) *Reloc {
for i := 0; i < len(s.R); i++ {
if s.R[i].Off == off {
return &s.R[i:][0]
}
}
return nil
}
func decode_reloc_sym(s *LSym, off int32) *LSym {
r := decode_reloc(s, off)
if r == nil {
return nil
}
return r.Sym
}
func decode_inuxi(p []byte, sz int) uint64 {
switch sz {
case 2:
return uint64(Ctxt.Arch.ByteOrder.Uint16(p))
case 4:
return uint64(Ctxt.Arch.ByteOrder.Uint32(p))
case 8:
return Ctxt.Arch.ByteOrder.Uint64(p)
default:
Exitf("dwarf: decode inuxi %d", sz)
panic("unreachable")
}
}
// commonsize returns the size of the common prefix for all type
// structures (runtime._type).
func commonsize() int {
return 9*Thearch.Ptrsize + 8
}
// Type.commonType.kind
func decodetype_kind(s *LSym) uint8 {
return uint8(s.P[2*Thearch.Ptrsize+7] & obj.KindMask) // 0x13 / 0x1f
}
// Type.commonType.kind
func decodetype_noptr(s *LSym) uint8 {
return uint8(s.P[2*Thearch.Ptrsize+7] & obj.KindNoPointers) // 0x13 / 0x1f
}
// Type.commonType.kind
func decodetype_usegcprog(s *LSym) uint8 {
return uint8(s.P[2*Thearch.Ptrsize+7] & obj.KindGCProg) // 0x13 / 0x1f
}
// Type.commonType.size
func decodetype_size(s *LSym) int64 {
return int64(decode_inuxi(s.P, Thearch.Ptrsize)) // 0x8 / 0x10
}
// Type.commonType.gc
func decodetype_gcprog(s *LSym) *LSym {
if s.Type == obj.SDYNIMPORT {
// The gcprog for "type.$name" is calle "type..gcprog.$name".
x := "type..gcprog." + s.Name[5:]
return Linklookup(Ctxt, x, 0)
}
return decode_reloc_sym(s, 2*int32(Thearch.Ptrsize)+8+2*int32(Thearch.Ptrsize))
}
func decodetype_gcprog_shlib(s *LSym) uint64 {
return decode_inuxi(s.P[2*int32(Thearch.Ptrsize)+8+1*int32(Thearch.Ptrsize):], Thearch.Ptrsize)
}
func decodetype_gcmask(s *LSym) []byte {
if s.Type == obj.SDYNIMPORT {
// ldshlibsyms makes special efforts to read the value
// of gcmask for types defined in that shared library.
return s.gcmask
}
mask := decode_reloc_sym(s, 2*int32(Thearch.Ptrsize)+8+1*int32(Thearch.Ptrsize))
return mask.P
}
// Type.ArrayType.elem and Type.SliceType.Elem
func decodetype_arrayelem(s *LSym) *LSym {
return decode_reloc_sym(s, int32(commonsize())) // 0x1c / 0x30
}
func decodetype_arraylen(s *LSym) int64 {
return int64(decode_inuxi(s.P[commonsize()+2*Thearch.Ptrsize:], Thearch.Ptrsize))
}
// Type.PtrType.elem
func decodetype_ptrelem(s *LSym) *LSym {
return decode_reloc_sym(s, int32(commonsize())) // 0x1c / 0x30
}
// Type.MapType.key, elem
func decodetype_mapkey(s *LSym) *LSym {
return decode_reloc_sym(s, int32(commonsize())) // 0x1c / 0x30
}
func decodetype_mapvalue(s *LSym) *LSym {
return decode_reloc_sym(s, int32(commonsize())+int32(Thearch.Ptrsize)) // 0x20 / 0x38
}
// Type.ChanType.elem
func decodetype_chanelem(s *LSym) *LSym {
return decode_reloc_sym(s, int32(commonsize())) // 0x1c / 0x30
}
// Type.FuncType.dotdotdot
func decodetype_funcdotdotdot(s *LSym) int {
return int(s.P[commonsize()])
}
// Type.FuncType.in.length
func decodetype_funcincount(s *LSym) int {
return int(decode_inuxi(s.P[commonsize()+2*Thearch.Ptrsize:], Thearch.Intsize))
}
func decodetype_funcoutcount(s *LSym) int {
return int(decode_inuxi(s.P[commonsize()+3*Thearch.Ptrsize+2*Thearch.Intsize:], Thearch.Intsize))
}
func decodetype_funcintype(s *LSym, i int) *LSym {
r := decode_reloc(s, int32(commonsize())+int32(Thearch.Ptrsize))
if r == nil {
return nil
}
return decode_reloc_sym(r.Sym, int32(r.Add+int64(int32(i)*int32(Thearch.Ptrsize))))
}
func decodetype_funcouttype(s *LSym, i int) *LSym {
r := decode_reloc(s, int32(commonsize())+2*int32(Thearch.Ptrsize)+2*int32(Thearch.Intsize))
if r == nil {
return nil
}
return decode_reloc_sym(r.Sym, int32(r.Add+int64(int32(i)*int32(Thearch.Ptrsize))))
}
// Type.StructType.fields.Slice::length
func decodetype_structfieldcount(s *LSym) int {
return int(decode_inuxi(s.P[commonsize()+Thearch.Ptrsize:], Thearch.Intsize))
}
func structfieldsize() int {
return 5 * Thearch.Ptrsize
}
// Type.StructType.fields[]-> name, typ and offset.
func decodetype_structfieldname(s *LSym, i int) string {
// go.string."foo" 0x28 / 0x40
s = decode_reloc_sym(s, int32(commonsize())+int32(Thearch.Ptrsize)+2*int32(Thearch.Intsize)+int32(i)*int32(structfieldsize()))
if s == nil { // embedded structs have a nil name.
return ""
}
r := decode_reloc(s, 0) // s has a pointer to the string data at offset 0
if r == nil { // shouldn't happen.
return ""
}
return cstring(r.Sym.P[r.Add:])
}
func decodetype_structfieldtype(s *LSym, i int) *LSym {
return decode_reloc_sym(s, int32(commonsize())+int32(Thearch.Ptrsize)+2*int32(Thearch.Intsize)+int32(i)*int32(structfieldsize())+2*int32(Thearch.Ptrsize))
}
func decodetype_structfieldoffs(s *LSym, i int) int64 {
return int64(decode_inuxi(s.P[commonsize()+Thearch.Ptrsize+2*Thearch.Intsize+i*structfieldsize()+4*Thearch.Ptrsize:], Thearch.Intsize))
}
// InterfaceType.methods.length
func decodetype_ifacemethodcount(s *LSym) int64 {
return int64(decode_inuxi(s.P[commonsize()+Thearch.Ptrsize:], Thearch.Intsize))
}