forked from go-delve/delve
-
Notifications
You must be signed in to change notification settings - Fork 0
/
disasm_amd64.go
183 lines (158 loc) · 4.36 KB
/
disasm_amd64.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
package proc
import (
"debug/gosym"
"encoding/binary"
"rsc.io/x86/x86asm"
)
var maxInstructionLength uint64 = 15
type ArchInst x86asm.Inst
func asmDecode(mem []byte, pc uint64) (*ArchInst, error) {
inst, err := x86asm.Decode(mem, 64)
if err != nil {
return nil, err
}
patchPCRel(pc, &inst)
r := ArchInst(inst)
return &r, nil
}
func (inst *ArchInst) Size() int {
return inst.Len
}
// converts PC relative arguments to absolute addresses
func patchPCRel(pc uint64, inst *x86asm.Inst) {
for i := range inst.Args {
rel, isrel := inst.Args[i].(x86asm.Rel)
if isrel {
inst.Args[i] = x86asm.Imm(int64(pc) + int64(rel) + int64(inst.Len))
}
}
return
}
func (inst *AsmInstruction) Text(flavour AssemblyFlavour) string {
if inst.Inst == nil {
return "?"
}
var text string
switch flavour {
case GNUFlavour:
text = x86asm.GNUSyntax(x86asm.Inst(*inst.Inst))
case IntelFlavour:
fallthrough
default:
text = x86asm.IntelSyntax(x86asm.Inst(*inst.Inst))
}
if inst.IsCall() && inst.DestLoc != nil && inst.DestLoc.Fn != nil {
text += " " + inst.DestLoc.Fn.Name
}
return text
}
func (inst *AsmInstruction) IsCall() bool {
return inst.Inst.Op == x86asm.CALL || inst.Inst.Op == x86asm.LCALL
}
func (thread *Thread) resolveCallArg(inst *ArchInst, currentGoroutine bool, regs Registers) *Location {
if inst.Op != x86asm.CALL && inst.Op != x86asm.LCALL {
return nil
}
var pc uint64
var err error
switch arg := inst.Args[0].(type) {
case x86asm.Imm:
pc = uint64(arg)
case x86asm.Reg:
if !currentGoroutine || regs == nil {
return nil
}
pc, err = regs.Get(int(arg))
if err != nil {
return nil
}
case x86asm.Mem:
if !currentGoroutine || regs == nil {
return nil
}
if arg.Segment != 0 {
return nil
}
regs, err := thread.Registers(false)
if err != nil {
return nil
}
base, err1 := regs.Get(int(arg.Base))
index, err2 := regs.Get(int(arg.Index))
if err1 != nil || err2 != nil {
return nil
}
addr := uintptr(int64(base) + int64(index*uint64(arg.Scale)) + arg.Disp)
//TODO: should this always be 64 bits instead of inst.MemBytes?
pcbytes, err := thread.readMemory(addr, inst.MemBytes)
if err != nil {
return nil
}
pc = binary.LittleEndian.Uint64(pcbytes)
default:
return nil
}
file, line, fn := thread.dbp.PCToLine(pc)
if fn == nil {
return nil
}
return &Location{PC: pc, File: file, Line: line, Fn: fn}
}
type instrseq []x86asm.Op
// Possible stacksplit prologues are inserted by stacksplit in
// $GOROOT/src/cmd/internal/obj/x86/obj6.go.
// The stacksplit prologue will always begin with loading curg in CX, this
// instruction is added by load_g_cx in the same file and is either 1 or 2
// MOVs.
var prologues []instrseq
func init() {
var tinyStacksplit = instrseq{x86asm.CMP, x86asm.JBE}
var smallStacksplit = instrseq{x86asm.LEA, x86asm.CMP, x86asm.JBE}
var bigStacksplit = instrseq{x86asm.MOV, x86asm.CMP, x86asm.JE, x86asm.LEA, x86asm.SUB, x86asm.CMP, x86asm.JBE}
var unixGetG = instrseq{x86asm.MOV}
var windowsGetG = instrseq{x86asm.MOV, x86asm.MOV}
prologues = make([]instrseq, 0, 2*3)
for _, getG := range []instrseq{unixGetG, windowsGetG} {
for _, stacksplit := range []instrseq{tinyStacksplit, smallStacksplit, bigStacksplit} {
prologue := make(instrseq, 0, len(getG)+len(stacksplit))
prologue = append(prologue, getG...)
prologue = append(prologue, stacksplit...)
prologues = append(prologues, prologue)
}
}
}
// FirstPCAfterPrologue returns the address of the first instruction after the prologue for function fn
// If sameline is set FirstPCAfterPrologue will always return an address associated with the same line as fn.Entry
func (dbp *Process) FirstPCAfterPrologue(fn *gosym.Func, sameline bool) (uint64, error) {
text, err := dbp.CurrentThread.Disassemble(fn.Entry, fn.End, false)
if err != nil {
return fn.Entry, err
}
if len(text) <= 0 {
return fn.Entry, nil
}
for _, prologue := range prologues {
if len(prologue) >= len(text) {
continue
}
if checkPrologue(text, prologue) {
r := &text[len(prologue)]
if sameline {
if r.Loc.Line != text[0].Loc.Line {
return fn.Entry, nil
}
}
return r.Loc.PC, nil
}
}
return fn.Entry, nil
}
func checkPrologue(s []AsmInstruction, prologuePattern instrseq) bool {
line := s[0].Loc.Line
for i, op := range prologuePattern {
if s[i].Inst.Op != op || s[i].Loc.Line != line {
return false
}
}
return true
}