mirror of
https://github.com/cwinfo/matterbridge.git
synced 2024-11-23 16:21:37 +00:00
601 lines
13 KiB
Go
601 lines
13 KiB
Go
// Copyright 2016 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 dwarf generates DWARF debugging information.
|
|
// DWARF generation is split between the compiler and the linker,
|
|
// this package contains the shared code.
|
|
package dwarf
|
|
|
|
import (
|
|
"fmt"
|
|
)
|
|
|
|
// InfoPrefix is the prefix for all the symbols containing DWARF info entries.
|
|
const InfoPrefix = "go.info."
|
|
|
|
// Sym represents a symbol.
|
|
type Sym interface {
|
|
}
|
|
|
|
// A Var represents a local variable or a function parameter.
|
|
type Var struct {
|
|
Name string
|
|
Abbrev int // Either DW_ABRV_AUTO or DW_ABRV_PARAM
|
|
Offset int32
|
|
Type Sym
|
|
Link *Var
|
|
}
|
|
|
|
// A Context specifies how to add data to a Sym.
|
|
type Context interface {
|
|
PtrSize() int
|
|
AddInt(s Sym, size int, i int64)
|
|
AddBytes(s Sym, b []byte)
|
|
AddAddress(s Sym, t interface{}, ofs int64)
|
|
AddSectionOffset(s Sym, size int, t interface{}, ofs int64)
|
|
AddString(s Sym, v string)
|
|
SymValue(s Sym) int64
|
|
}
|
|
|
|
// AppendUleb128 appends v to b using DWARF's unsigned LEB128 encoding.
|
|
func AppendUleb128(b []byte, v uint64) []byte {
|
|
for {
|
|
c := uint8(v & 0x7f)
|
|
v >>= 7
|
|
if v != 0 {
|
|
c |= 0x80
|
|
}
|
|
b = append(b, c)
|
|
if c&0x80 == 0 {
|
|
break
|
|
}
|
|
}
|
|
return b
|
|
}
|
|
|
|
// AppendSleb128 appends v to b using DWARF's signed LEB128 encoding.
|
|
func AppendSleb128(b []byte, v int64) []byte {
|
|
for {
|
|
c := uint8(v & 0x7f)
|
|
s := uint8(v & 0x40)
|
|
v >>= 7
|
|
if (v != -1 || s == 0) && (v != 0 || s != 0) {
|
|
c |= 0x80
|
|
}
|
|
b = append(b, c)
|
|
if c&0x80 == 0 {
|
|
break
|
|
}
|
|
}
|
|
return b
|
|
}
|
|
|
|
var encbuf [20]byte
|
|
|
|
// AppendUleb128 appends v to s using DWARF's unsigned LEB128 encoding.
|
|
func Uleb128put(ctxt Context, s Sym, v int64) {
|
|
b := AppendUleb128(encbuf[:0], uint64(v))
|
|
ctxt.AddBytes(s, b)
|
|
}
|
|
|
|
// AppendUleb128 appends v to s using DWARF's signed LEB128 encoding.
|
|
func Sleb128put(ctxt Context, s Sym, v int64) {
|
|
b := AppendSleb128(encbuf[:0], v)
|
|
ctxt.AddBytes(s, b)
|
|
}
|
|
|
|
/*
|
|
* Defining Abbrevs. This is hardcoded, and there will be
|
|
* only a handful of them. The DWARF spec places no restriction on
|
|
* the ordering of attributes in the Abbrevs and DIEs, and we will
|
|
* always write them out in the order of declaration in the abbrev.
|
|
*/
|
|
type dwAttrForm struct {
|
|
attr uint16
|
|
form uint8
|
|
}
|
|
|
|
// Go-specific type attributes.
|
|
const (
|
|
DW_AT_go_kind = 0x2900
|
|
DW_AT_go_key = 0x2901
|
|
DW_AT_go_elem = 0x2902
|
|
|
|
DW_AT_internal_location = 253 // params and locals; not emitted
|
|
)
|
|
|
|
// Index into the abbrevs table below.
|
|
// Keep in sync with ispubname() and ispubtype() below.
|
|
// ispubtype considers >= NULLTYPE public
|
|
const (
|
|
DW_ABRV_NULL = iota
|
|
DW_ABRV_COMPUNIT
|
|
DW_ABRV_FUNCTION
|
|
DW_ABRV_VARIABLE
|
|
DW_ABRV_AUTO
|
|
DW_ABRV_PARAM
|
|
DW_ABRV_STRUCTFIELD
|
|
DW_ABRV_FUNCTYPEPARAM
|
|
DW_ABRV_DOTDOTDOT
|
|
DW_ABRV_ARRAYRANGE
|
|
DW_ABRV_NULLTYPE
|
|
DW_ABRV_BASETYPE
|
|
DW_ABRV_ARRAYTYPE
|
|
DW_ABRV_CHANTYPE
|
|
DW_ABRV_FUNCTYPE
|
|
DW_ABRV_IFACETYPE
|
|
DW_ABRV_MAPTYPE
|
|
DW_ABRV_PTRTYPE
|
|
DW_ABRV_BARE_PTRTYPE // only for void*, no DW_AT_type attr to please gdb 6.
|
|
DW_ABRV_SLICETYPE
|
|
DW_ABRV_STRINGTYPE
|
|
DW_ABRV_STRUCTTYPE
|
|
DW_ABRV_TYPEDECL
|
|
DW_NABRV
|
|
)
|
|
|
|
type dwAbbrev struct {
|
|
tag uint8
|
|
children uint8
|
|
attr []dwAttrForm
|
|
}
|
|
|
|
var abbrevs = [DW_NABRV]dwAbbrev{
|
|
/* The mandatory DW_ABRV_NULL entry. */
|
|
{0, 0, []dwAttrForm{}},
|
|
|
|
/* COMPUNIT */
|
|
{
|
|
DW_TAG_compile_unit,
|
|
DW_CHILDREN_yes,
|
|
[]dwAttrForm{
|
|
{DW_AT_name, DW_FORM_string},
|
|
{DW_AT_language, DW_FORM_data1},
|
|
{DW_AT_low_pc, DW_FORM_addr},
|
|
{DW_AT_high_pc, DW_FORM_addr},
|
|
{DW_AT_stmt_list, DW_FORM_data4},
|
|
{DW_AT_comp_dir, DW_FORM_string},
|
|
},
|
|
},
|
|
|
|
/* FUNCTION */
|
|
{
|
|
DW_TAG_subprogram,
|
|
DW_CHILDREN_yes,
|
|
[]dwAttrForm{
|
|
{DW_AT_name, DW_FORM_string},
|
|
{DW_AT_low_pc, DW_FORM_addr},
|
|
{DW_AT_high_pc, DW_FORM_addr},
|
|
{DW_AT_external, DW_FORM_flag},
|
|
},
|
|
},
|
|
|
|
/* VARIABLE */
|
|
{
|
|
DW_TAG_variable,
|
|
DW_CHILDREN_no,
|
|
[]dwAttrForm{
|
|
{DW_AT_name, DW_FORM_string},
|
|
{DW_AT_location, DW_FORM_block1},
|
|
{DW_AT_type, DW_FORM_ref_addr},
|
|
{DW_AT_external, DW_FORM_flag},
|
|
},
|
|
},
|
|
|
|
/* AUTO */
|
|
{
|
|
DW_TAG_variable,
|
|
DW_CHILDREN_no,
|
|
[]dwAttrForm{
|
|
{DW_AT_name, DW_FORM_string},
|
|
{DW_AT_location, DW_FORM_block1},
|
|
{DW_AT_type, DW_FORM_ref_addr},
|
|
},
|
|
},
|
|
|
|
/* PARAM */
|
|
{
|
|
DW_TAG_formal_parameter,
|
|
DW_CHILDREN_no,
|
|
[]dwAttrForm{
|
|
{DW_AT_name, DW_FORM_string},
|
|
{DW_AT_location, DW_FORM_block1},
|
|
{DW_AT_type, DW_FORM_ref_addr},
|
|
},
|
|
},
|
|
|
|
/* STRUCTFIELD */
|
|
{
|
|
DW_TAG_member,
|
|
DW_CHILDREN_no,
|
|
[]dwAttrForm{
|
|
{DW_AT_name, DW_FORM_string},
|
|
{DW_AT_data_member_location, DW_FORM_block1},
|
|
{DW_AT_type, DW_FORM_ref_addr},
|
|
},
|
|
},
|
|
|
|
/* FUNCTYPEPARAM */
|
|
{
|
|
DW_TAG_formal_parameter,
|
|
DW_CHILDREN_no,
|
|
|
|
// No name!
|
|
[]dwAttrForm{
|
|
{DW_AT_type, DW_FORM_ref_addr},
|
|
},
|
|
},
|
|
|
|
/* DOTDOTDOT */
|
|
{
|
|
DW_TAG_unspecified_parameters,
|
|
DW_CHILDREN_no,
|
|
[]dwAttrForm{},
|
|
},
|
|
|
|
/* ARRAYRANGE */
|
|
{
|
|
DW_TAG_subrange_type,
|
|
DW_CHILDREN_no,
|
|
|
|
// No name!
|
|
[]dwAttrForm{
|
|
{DW_AT_type, DW_FORM_ref_addr},
|
|
{DW_AT_count, DW_FORM_udata},
|
|
},
|
|
},
|
|
|
|
// Below here are the types considered public by ispubtype
|
|
/* NULLTYPE */
|
|
{
|
|
DW_TAG_unspecified_type,
|
|
DW_CHILDREN_no,
|
|
[]dwAttrForm{
|
|
{DW_AT_name, DW_FORM_string},
|
|
},
|
|
},
|
|
|
|
/* BASETYPE */
|
|
{
|
|
DW_TAG_base_type,
|
|
DW_CHILDREN_no,
|
|
[]dwAttrForm{
|
|
{DW_AT_name, DW_FORM_string},
|
|
{DW_AT_encoding, DW_FORM_data1},
|
|
{DW_AT_byte_size, DW_FORM_data1},
|
|
{DW_AT_go_kind, DW_FORM_data1},
|
|
},
|
|
},
|
|
|
|
/* ARRAYTYPE */
|
|
// child is subrange with upper bound
|
|
{
|
|
DW_TAG_array_type,
|
|
DW_CHILDREN_yes,
|
|
[]dwAttrForm{
|
|
{DW_AT_name, DW_FORM_string},
|
|
{DW_AT_type, DW_FORM_ref_addr},
|
|
{DW_AT_byte_size, DW_FORM_udata},
|
|
{DW_AT_go_kind, DW_FORM_data1},
|
|
},
|
|
},
|
|
|
|
/* CHANTYPE */
|
|
{
|
|
DW_TAG_typedef,
|
|
DW_CHILDREN_no,
|
|
[]dwAttrForm{
|
|
{DW_AT_name, DW_FORM_string},
|
|
{DW_AT_type, DW_FORM_ref_addr},
|
|
{DW_AT_go_kind, DW_FORM_data1},
|
|
{DW_AT_go_elem, DW_FORM_ref_addr},
|
|
},
|
|
},
|
|
|
|
/* FUNCTYPE */
|
|
{
|
|
DW_TAG_subroutine_type,
|
|
DW_CHILDREN_yes,
|
|
[]dwAttrForm{
|
|
{DW_AT_name, DW_FORM_string},
|
|
// {DW_AT_type, DW_FORM_ref_addr},
|
|
{DW_AT_go_kind, DW_FORM_data1},
|
|
},
|
|
},
|
|
|
|
/* IFACETYPE */
|
|
{
|
|
DW_TAG_typedef,
|
|
DW_CHILDREN_yes,
|
|
[]dwAttrForm{
|
|
{DW_AT_name, DW_FORM_string},
|
|
{DW_AT_type, DW_FORM_ref_addr},
|
|
{DW_AT_go_kind, DW_FORM_data1},
|
|
},
|
|
},
|
|
|
|
/* MAPTYPE */
|
|
{
|
|
DW_TAG_typedef,
|
|
DW_CHILDREN_no,
|
|
[]dwAttrForm{
|
|
{DW_AT_name, DW_FORM_string},
|
|
{DW_AT_type, DW_FORM_ref_addr},
|
|
{DW_AT_go_kind, DW_FORM_data1},
|
|
{DW_AT_go_key, DW_FORM_ref_addr},
|
|
{DW_AT_go_elem, DW_FORM_ref_addr},
|
|
},
|
|
},
|
|
|
|
/* PTRTYPE */
|
|
{
|
|
DW_TAG_pointer_type,
|
|
DW_CHILDREN_no,
|
|
[]dwAttrForm{
|
|
{DW_AT_name, DW_FORM_string},
|
|
{DW_AT_type, DW_FORM_ref_addr},
|
|
{DW_AT_go_kind, DW_FORM_data1},
|
|
},
|
|
},
|
|
|
|
/* BARE_PTRTYPE */
|
|
{
|
|
DW_TAG_pointer_type,
|
|
DW_CHILDREN_no,
|
|
[]dwAttrForm{
|
|
{DW_AT_name, DW_FORM_string},
|
|
},
|
|
},
|
|
|
|
/* SLICETYPE */
|
|
{
|
|
DW_TAG_structure_type,
|
|
DW_CHILDREN_yes,
|
|
[]dwAttrForm{
|
|
{DW_AT_name, DW_FORM_string},
|
|
{DW_AT_byte_size, DW_FORM_udata},
|
|
{DW_AT_go_kind, DW_FORM_data1},
|
|
{DW_AT_go_elem, DW_FORM_ref_addr},
|
|
},
|
|
},
|
|
|
|
/* STRINGTYPE */
|
|
{
|
|
DW_TAG_structure_type,
|
|
DW_CHILDREN_yes,
|
|
[]dwAttrForm{
|
|
{DW_AT_name, DW_FORM_string},
|
|
{DW_AT_byte_size, DW_FORM_udata},
|
|
{DW_AT_go_kind, DW_FORM_data1},
|
|
},
|
|
},
|
|
|
|
/* STRUCTTYPE */
|
|
{
|
|
DW_TAG_structure_type,
|
|
DW_CHILDREN_yes,
|
|
[]dwAttrForm{
|
|
{DW_AT_name, DW_FORM_string},
|
|
{DW_AT_byte_size, DW_FORM_udata},
|
|
{DW_AT_go_kind, DW_FORM_data1},
|
|
},
|
|
},
|
|
|
|
/* TYPEDECL */
|
|
{
|
|
DW_TAG_typedef,
|
|
DW_CHILDREN_no,
|
|
[]dwAttrForm{
|
|
{DW_AT_name, DW_FORM_string},
|
|
{DW_AT_type, DW_FORM_ref_addr},
|
|
},
|
|
},
|
|
}
|
|
|
|
// GetAbbrev returns the contents of the .debug_abbrev section.
|
|
func GetAbbrev() []byte {
|
|
var buf []byte
|
|
for i := 1; i < DW_NABRV; i++ {
|
|
// See section 7.5.3
|
|
buf = AppendUleb128(buf, uint64(i))
|
|
|
|
buf = AppendUleb128(buf, uint64(abbrevs[i].tag))
|
|
buf = append(buf, byte(abbrevs[i].children))
|
|
for _, f := range abbrevs[i].attr {
|
|
buf = AppendUleb128(buf, uint64(f.attr))
|
|
buf = AppendUleb128(buf, uint64(f.form))
|
|
}
|
|
buf = append(buf, 0, 0)
|
|
}
|
|
return append(buf, 0)
|
|
}
|
|
|
|
/*
|
|
* Debugging Information Entries and their attributes.
|
|
*/
|
|
|
|
// DWAttr represents an attribute of a DWDie.
|
|
//
|
|
// For DW_CLS_string and _block, value should contain the length, and
|
|
// data the data, for _reference, value is 0 and data is a DWDie* to
|
|
// the referenced instance, for all others, value is the whole thing
|
|
// and data is null.
|
|
type DWAttr struct {
|
|
Link *DWAttr
|
|
Atr uint16 // DW_AT_
|
|
Cls uint8 // DW_CLS_
|
|
Value int64
|
|
Data interface{}
|
|
}
|
|
|
|
// DWDie represents a DWARF debug info entry.
|
|
type DWDie struct {
|
|
Abbrev int
|
|
Link *DWDie
|
|
Child *DWDie
|
|
Attr *DWAttr
|
|
Sym Sym
|
|
}
|
|
|
|
func putattr(ctxt Context, s Sym, abbrev int, form int, cls int, value int64, data interface{}) error {
|
|
switch form {
|
|
case DW_FORM_addr: // address
|
|
ctxt.AddAddress(s, data, value)
|
|
|
|
case DW_FORM_block1: // block
|
|
if cls == DW_CLS_ADDRESS {
|
|
ctxt.AddInt(s, 1, int64(1+ctxt.PtrSize()))
|
|
ctxt.AddInt(s, 1, DW_OP_addr)
|
|
ctxt.AddAddress(s, data, 0)
|
|
break
|
|
}
|
|
|
|
value &= 0xff
|
|
ctxt.AddInt(s, 1, value)
|
|
p := data.([]byte)[:value]
|
|
ctxt.AddBytes(s, p)
|
|
|
|
case DW_FORM_block2: // block
|
|
value &= 0xffff
|
|
|
|
ctxt.AddInt(s, 2, value)
|
|
p := data.([]byte)[:value]
|
|
ctxt.AddBytes(s, p)
|
|
|
|
case DW_FORM_block4: // block
|
|
value &= 0xffffffff
|
|
|
|
ctxt.AddInt(s, 4, value)
|
|
p := data.([]byte)[:value]
|
|
ctxt.AddBytes(s, p)
|
|
|
|
case DW_FORM_block: // block
|
|
Uleb128put(ctxt, s, value)
|
|
|
|
p := data.([]byte)[:value]
|
|
ctxt.AddBytes(s, p)
|
|
|
|
case DW_FORM_data1: // constant
|
|
ctxt.AddInt(s, 1, value)
|
|
|
|
case DW_FORM_data2: // constant
|
|
ctxt.AddInt(s, 2, value)
|
|
|
|
case DW_FORM_data4: // constant, {line,loclist,mac,rangelist}ptr
|
|
if cls == DW_CLS_PTR { // DW_AT_stmt_list
|
|
ctxt.AddSectionOffset(s, 4, data, 0)
|
|
break
|
|
}
|
|
ctxt.AddInt(s, 4, value)
|
|
|
|
case DW_FORM_data8: // constant, {line,loclist,mac,rangelist}ptr
|
|
ctxt.AddInt(s, 8, value)
|
|
|
|
case DW_FORM_sdata: // constant
|
|
Sleb128put(ctxt, s, value)
|
|
|
|
case DW_FORM_udata: // constant
|
|
Uleb128put(ctxt, s, value)
|
|
|
|
case DW_FORM_string: // string
|
|
str := data.(string)
|
|
ctxt.AddString(s, str)
|
|
// TODO(ribrdb): verify padded strings are never used and remove this
|
|
for i := int64(len(str)); i < value; i++ {
|
|
ctxt.AddInt(s, 1, 0)
|
|
}
|
|
|
|
case DW_FORM_flag: // flag
|
|
if value != 0 {
|
|
ctxt.AddInt(s, 1, 1)
|
|
} else {
|
|
ctxt.AddInt(s, 1, 0)
|
|
}
|
|
|
|
// In DWARF 2 (which is what we claim to generate),
|
|
// the ref_addr is the same size as a normal address.
|
|
// In DWARF 3 it is always 32 bits, unless emitting a large
|
|
// (> 4 GB of debug info aka "64-bit") unit, which we don't implement.
|
|
case DW_FORM_ref_addr: // reference to a DIE in the .info section
|
|
if data == nil {
|
|
return fmt.Errorf("dwarf: null reference in %d", abbrev)
|
|
} else {
|
|
ctxt.AddSectionOffset(s, ctxt.PtrSize(), data, 0)
|
|
}
|
|
|
|
case DW_FORM_ref1, // reference within the compilation unit
|
|
DW_FORM_ref2, // reference
|
|
DW_FORM_ref4, // reference
|
|
DW_FORM_ref8, // reference
|
|
DW_FORM_ref_udata, // reference
|
|
|
|
DW_FORM_strp, // string
|
|
DW_FORM_indirect: // (see Section 7.5.3)
|
|
fallthrough
|
|
default:
|
|
return fmt.Errorf("dwarf: unsupported attribute form %d / class %d", form, cls)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// PutAttrs writes the attributes for a DIE to symbol 's'.
|
|
//
|
|
// Note that we can (and do) add arbitrary attributes to a DIE, but
|
|
// only the ones actually listed in the Abbrev will be written out.
|
|
func PutAttrs(ctxt Context, s Sym, abbrev int, attr *DWAttr) {
|
|
Outer:
|
|
for _, f := range abbrevs[abbrev].attr {
|
|
for ap := attr; ap != nil; ap = ap.Link {
|
|
if ap.Atr == f.attr {
|
|
putattr(ctxt, s, abbrev, int(f.form), int(ap.Cls), ap.Value, ap.Data)
|
|
continue Outer
|
|
}
|
|
}
|
|
|
|
putattr(ctxt, s, abbrev, int(f.form), 0, 0, nil)
|
|
}
|
|
}
|
|
|
|
// HasChildren returns true if 'die' uses an abbrev that supports children.
|
|
func HasChildren(die *DWDie) bool {
|
|
return abbrevs[die.Abbrev].children != 0
|
|
}
|
|
|
|
// PutFunc writes a DIE for a function to s.
|
|
// It also writes child DIEs for each variable in vars.
|
|
func PutFunc(ctxt Context, s Sym, name string, external bool, startPC Sym, size int64, vars *Var) {
|
|
Uleb128put(ctxt, s, DW_ABRV_FUNCTION)
|
|
putattr(ctxt, s, DW_ABRV_FUNCTION, DW_FORM_string, DW_CLS_STRING, int64(len(name)), name)
|
|
putattr(ctxt, s, DW_ABRV_FUNCTION, DW_FORM_addr, DW_CLS_ADDRESS, 0, startPC)
|
|
putattr(ctxt, s, DW_ABRV_FUNCTION, DW_FORM_addr, DW_CLS_ADDRESS, size+ctxt.SymValue(startPC), startPC)
|
|
var ev int64
|
|
if external {
|
|
ev = 1
|
|
}
|
|
putattr(ctxt, s, DW_ABRV_FUNCTION, DW_FORM_flag, DW_CLS_FLAG, ev, 0)
|
|
names := make(map[string]bool)
|
|
for v := vars; v != nil; v = v.Link {
|
|
var n string
|
|
if names[v.Name] {
|
|
n = fmt.Sprintf("%s#%d", v.Name, len(names))
|
|
} else {
|
|
n = v.Name
|
|
}
|
|
names[n] = true
|
|
|
|
Uleb128put(ctxt, s, int64(v.Abbrev))
|
|
putattr(ctxt, s, v.Abbrev, DW_FORM_string, DW_CLS_STRING, int64(len(n)), n)
|
|
loc := append(encbuf[:0], DW_OP_call_frame_cfa)
|
|
if v.Offset != 0 {
|
|
loc = append(loc, DW_OP_consts)
|
|
loc = AppendSleb128(loc, int64(v.Offset))
|
|
loc = append(loc, DW_OP_plus)
|
|
}
|
|
putattr(ctxt, s, v.Abbrev, DW_FORM_block1, DW_CLS_BLOCK, int64(len(loc)), loc)
|
|
putattr(ctxt, s, v.Abbrev, DW_FORM_ref_addr, DW_CLS_REFERENCE, 0, v.Type)
|
|
|
|
}
|
|
Uleb128put(ctxt, s, 0)
|
|
}
|