mirror of
https://github.com/beego/bee.git
synced 2024-11-05 22:00:54 +00:00
430 lines
11 KiB
Go
430 lines
11 KiB
Go
package frame
|
|
|
|
import (
|
|
"bytes"
|
|
"encoding/binary"
|
|
"fmt"
|
|
|
|
"github.com/derekparker/delve/dwarf/util"
|
|
)
|
|
|
|
type CurrentFrameAddress struct {
|
|
register uint64
|
|
offset int64
|
|
expression []byte
|
|
rule byte
|
|
}
|
|
|
|
type DWRule struct {
|
|
rule byte
|
|
offset int64
|
|
newreg uint64
|
|
expression []byte
|
|
}
|
|
|
|
type FrameContext struct {
|
|
loc uint64
|
|
order binary.ByteOrder
|
|
address uint64
|
|
cfa CurrentFrameAddress
|
|
regs map[uint64]DWRule
|
|
initialRegs map[uint64]DWRule
|
|
prevRegs map[uint64]DWRule
|
|
buf *bytes.Buffer
|
|
cie *CommonInformationEntry
|
|
codeAlignment uint64
|
|
dataAlignment int64
|
|
}
|
|
|
|
func (fctx *FrameContext) CFAOffset() int64 {
|
|
return fctx.cfa.offset
|
|
}
|
|
|
|
// Instructions used to recreate the table from the .debug_frame data.
|
|
const (
|
|
DW_CFA_nop = 0x0 // No ops
|
|
DW_CFA_set_loc = 0x01 // op1: address
|
|
DW_CFA_advance_loc1 = iota // op1: 1-bytes delta
|
|
DW_CFA_advance_loc2 // op1: 2-byte delta
|
|
DW_CFA_advance_loc4 // op1: 4-byte delta
|
|
DW_CFA_offset_extended // op1: ULEB128 register, op2: ULEB128 offset
|
|
DW_CFA_restore_extended // op1: ULEB128 register
|
|
DW_CFA_undefined // op1: ULEB128 register
|
|
DW_CFA_same_value // op1: ULEB128 register
|
|
DW_CFA_register // op1: ULEB128 register, op2: ULEB128 register
|
|
DW_CFA_remember_state // No ops
|
|
DW_CFA_restore_state // No ops
|
|
DW_CFA_def_cfa // op1: ULEB128 register, op2: ULEB128 offset
|
|
DW_CFA_def_cfa_register // op1: ULEB128 register
|
|
DW_CFA_def_cfa_offset // op1: ULEB128 offset
|
|
DW_CFA_def_cfa_expression // op1: BLOCK
|
|
DW_CFA_expression // op1: ULEB128 register, op2: BLOCK
|
|
DW_CFA_offset_extended_sf // op1: ULEB128 register, op2: SLEB128 BLOCK
|
|
DW_CFA_def_cfa_sf // op1: ULEB128 register, op2: SLEB128 offset
|
|
DW_CFA_def_cfa_offset_sf // op1: SLEB128 offset
|
|
DW_CFA_val_offset // op1: ULEB128, op2: ULEB128
|
|
DW_CFA_val_offset_sf // op1: ULEB128, op2: SLEB128
|
|
DW_CFA_val_expression // op1: ULEB128, op2: BLOCK
|
|
DW_CFA_lo_user = 0x1c // op1: BLOCK
|
|
DW_CFA_hi_user = 0x3f // op1: ULEB128 register, op2: BLOCK
|
|
DW_CFA_advance_loc = (0x1 << 6) // High 2 bits: 0x1, low 6: delta
|
|
DW_CFA_offset = (0x2 << 6) // High 2 bits: 0x2, low 6: register
|
|
DW_CFA_restore = (0x3 << 6) // High 2 bits: 0x3, low 6: register
|
|
)
|
|
|
|
// Rules defined for register values.
|
|
const (
|
|
rule_undefined = iota
|
|
rule_sameval
|
|
rule_offset
|
|
rule_valoffset
|
|
rule_register
|
|
rule_expression
|
|
rule_valexpression
|
|
rule_architectural
|
|
)
|
|
|
|
const low_6_offset = 0x3f
|
|
|
|
type instruction func(frame *FrameContext)
|
|
|
|
// // Mapping from DWARF opcode to function.
|
|
var fnlookup = map[byte]instruction{
|
|
DW_CFA_advance_loc: advanceloc,
|
|
DW_CFA_offset: offset,
|
|
DW_CFA_restore: restore,
|
|
DW_CFA_set_loc: setloc,
|
|
DW_CFA_advance_loc1: advanceloc1,
|
|
DW_CFA_advance_loc2: advanceloc2,
|
|
DW_CFA_advance_loc4: advanceloc4,
|
|
DW_CFA_offset_extended: offsetextended,
|
|
DW_CFA_restore_extended: restoreextended,
|
|
DW_CFA_undefined: undefined,
|
|
DW_CFA_same_value: samevalue,
|
|
DW_CFA_register: register,
|
|
DW_CFA_remember_state: rememberstate,
|
|
DW_CFA_restore_state: restorestate,
|
|
DW_CFA_def_cfa: defcfa,
|
|
DW_CFA_def_cfa_register: defcfaregister,
|
|
DW_CFA_def_cfa_offset: defcfaoffset,
|
|
DW_CFA_def_cfa_expression: defcfaexpression,
|
|
DW_CFA_expression: expression,
|
|
DW_CFA_offset_extended_sf: offsetextendedsf,
|
|
DW_CFA_def_cfa_sf: defcfasf,
|
|
DW_CFA_def_cfa_offset_sf: defcfaoffsetsf,
|
|
DW_CFA_val_offset: valoffset,
|
|
DW_CFA_val_offset_sf: valoffsetsf,
|
|
DW_CFA_val_expression: valexpression,
|
|
DW_CFA_lo_user: louser,
|
|
DW_CFA_hi_user: hiuser,
|
|
}
|
|
|
|
func executeCIEInstructions(cie *CommonInformationEntry) *FrameContext {
|
|
initialInstructions := make([]byte, len(cie.InitialInstructions))
|
|
copy(initialInstructions, cie.InitialInstructions)
|
|
frame := &FrameContext{
|
|
cie: cie,
|
|
regs: make(map[uint64]DWRule),
|
|
initialRegs: make(map[uint64]DWRule),
|
|
prevRegs: make(map[uint64]DWRule),
|
|
codeAlignment: cie.CodeAlignmentFactor,
|
|
dataAlignment: cie.DataAlignmentFactor,
|
|
buf: bytes.NewBuffer(initialInstructions),
|
|
}
|
|
|
|
frame.ExecuteDwarfProgram()
|
|
return frame
|
|
}
|
|
|
|
// Unwind the stack to find the return address register.
|
|
func executeDwarfProgramUntilPC(fde *FrameDescriptionEntry, pc uint64) *FrameContext {
|
|
frame := executeCIEInstructions(fde.CIE)
|
|
frame.order = fde.order
|
|
frame.loc = fde.Begin()
|
|
frame.address = pc
|
|
fdeInstructions := make([]byte, len(fde.Instructions))
|
|
copy(fdeInstructions, fde.Instructions)
|
|
frame.ExecuteUntilPC(fdeInstructions)
|
|
|
|
return frame
|
|
}
|
|
|
|
func (frame *FrameContext) ExecuteDwarfProgram() {
|
|
for frame.buf.Len() > 0 {
|
|
executeDwarfInstruction(frame)
|
|
}
|
|
}
|
|
|
|
// Execute dwarf instructions.
|
|
func (frame *FrameContext) ExecuteUntilPC(instructions []byte) {
|
|
frame.buf.Truncate(0)
|
|
frame.buf.Write(instructions)
|
|
|
|
// We only need to execute the instructions until
|
|
// ctx.loc > ctx.addess (which is the address we
|
|
// are currently at in the traced process).
|
|
for frame.address >= frame.loc && frame.buf.Len() > 0 {
|
|
executeDwarfInstruction(frame)
|
|
}
|
|
}
|
|
|
|
func executeDwarfInstruction(frame *FrameContext) {
|
|
instruction, err := frame.buf.ReadByte()
|
|
if err != nil {
|
|
panic("Could not read from instruction buffer")
|
|
}
|
|
|
|
if instruction == DW_CFA_nop {
|
|
return
|
|
}
|
|
|
|
fn := lookupFunc(instruction, frame.buf)
|
|
|
|
fn(frame)
|
|
}
|
|
|
|
func lookupFunc(instruction byte, buf *bytes.Buffer) instruction {
|
|
const high_2_bits = 0xc0
|
|
var restore bool
|
|
|
|
// Special case the 3 opcodes that have their argument encoded in the opcode itself.
|
|
switch instruction & high_2_bits {
|
|
case DW_CFA_advance_loc:
|
|
instruction = DW_CFA_advance_loc
|
|
restore = true
|
|
|
|
case DW_CFA_offset:
|
|
instruction = DW_CFA_offset
|
|
restore = true
|
|
|
|
case DW_CFA_restore:
|
|
instruction = DW_CFA_restore
|
|
restore = true
|
|
}
|
|
|
|
if restore {
|
|
// Restore the last byte as it actually contains the argument for the opcode.
|
|
err := buf.UnreadByte()
|
|
if err != nil {
|
|
panic("Could not unread byte")
|
|
}
|
|
}
|
|
|
|
fn, ok := fnlookup[instruction]
|
|
if !ok {
|
|
panic(fmt.Sprintf("Encountered an unexpected DWARF CFA opcode: %#v", instruction))
|
|
}
|
|
|
|
return fn
|
|
}
|
|
|
|
func advanceloc(frame *FrameContext) {
|
|
b, err := frame.buf.ReadByte()
|
|
if err != nil {
|
|
panic("Could not read byte")
|
|
}
|
|
|
|
delta := b & low_6_offset
|
|
frame.loc += uint64(delta) * frame.codeAlignment
|
|
}
|
|
|
|
func advanceloc1(frame *FrameContext) {
|
|
delta, err := frame.buf.ReadByte()
|
|
if err != nil {
|
|
panic("Could not read byte")
|
|
}
|
|
|
|
frame.loc += uint64(delta) * frame.codeAlignment
|
|
}
|
|
|
|
func advanceloc2(frame *FrameContext) {
|
|
var delta uint16
|
|
binary.Read(frame.buf, frame.order, &delta)
|
|
|
|
frame.loc += uint64(delta) * frame.codeAlignment
|
|
}
|
|
|
|
func advanceloc4(frame *FrameContext) {
|
|
var delta uint32
|
|
binary.Read(frame.buf, frame.order, &delta)
|
|
|
|
frame.loc += uint64(delta) * frame.codeAlignment
|
|
}
|
|
|
|
func offset(frame *FrameContext) {
|
|
b, err := frame.buf.ReadByte()
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
|
|
var (
|
|
reg = b & low_6_offset
|
|
offset, _ = util.DecodeULEB128(frame.buf)
|
|
)
|
|
|
|
frame.regs[uint64(reg)] = DWRule{offset: int64(offset) * frame.dataAlignment, rule: rule_offset}
|
|
}
|
|
|
|
func restore(frame *FrameContext) {
|
|
b, err := frame.buf.ReadByte()
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
|
|
reg := uint64(b & low_6_offset)
|
|
oldrule, ok := frame.initialRegs[reg]
|
|
if ok {
|
|
frame.regs[reg] = DWRule{offset: oldrule.offset, rule: rule_offset}
|
|
} else {
|
|
frame.regs[reg] = DWRule{rule: rule_undefined}
|
|
}
|
|
}
|
|
|
|
func setloc(frame *FrameContext) {
|
|
var loc uint64
|
|
binary.Read(frame.buf, frame.order, &loc)
|
|
|
|
frame.loc = loc
|
|
}
|
|
|
|
func offsetextended(frame *FrameContext) {
|
|
var (
|
|
reg, _ = util.DecodeULEB128(frame.buf)
|
|
offset, _ = util.DecodeULEB128(frame.buf)
|
|
)
|
|
|
|
frame.regs[reg] = DWRule{offset: int64(offset) * frame.dataAlignment, rule: rule_offset}
|
|
}
|
|
|
|
func undefined(frame *FrameContext) {
|
|
reg, _ := util.DecodeULEB128(frame.buf)
|
|
frame.regs[reg] = DWRule{rule: rule_undefined}
|
|
}
|
|
|
|
func samevalue(frame *FrameContext) {
|
|
reg, _ := util.DecodeULEB128(frame.buf)
|
|
frame.regs[reg] = DWRule{rule: rule_sameval}
|
|
}
|
|
|
|
func register(frame *FrameContext) {
|
|
reg1, _ := util.DecodeULEB128(frame.buf)
|
|
reg2, _ := util.DecodeULEB128(frame.buf)
|
|
frame.regs[reg1] = DWRule{newreg: reg2, rule: rule_register}
|
|
}
|
|
|
|
func rememberstate(frame *FrameContext) {
|
|
frame.prevRegs = frame.regs
|
|
}
|
|
|
|
func restorestate(frame *FrameContext) {
|
|
frame.regs = frame.prevRegs
|
|
}
|
|
|
|
func restoreextended(frame *FrameContext) {
|
|
reg, _ := util.DecodeULEB128(frame.buf)
|
|
|
|
oldrule, ok := frame.initialRegs[reg]
|
|
if ok {
|
|
frame.regs[reg] = DWRule{offset: oldrule.offset, rule: rule_offset}
|
|
} else {
|
|
frame.regs[reg] = DWRule{rule: rule_undefined}
|
|
}
|
|
}
|
|
|
|
func defcfa(frame *FrameContext) {
|
|
reg, _ := util.DecodeULEB128(frame.buf)
|
|
offset, _ := util.DecodeULEB128(frame.buf)
|
|
|
|
frame.cfa.register = reg
|
|
frame.cfa.offset = int64(offset)
|
|
}
|
|
|
|
func defcfaregister(frame *FrameContext) {
|
|
reg, _ := util.DecodeULEB128(frame.buf)
|
|
frame.cfa.register = reg
|
|
}
|
|
|
|
func defcfaoffset(frame *FrameContext) {
|
|
offset, _ := util.DecodeULEB128(frame.buf)
|
|
frame.cfa.offset = int64(offset)
|
|
}
|
|
|
|
func defcfasf(frame *FrameContext) {
|
|
reg, _ := util.DecodeULEB128(frame.buf)
|
|
offset, _ := util.DecodeSLEB128(frame.buf)
|
|
|
|
frame.cfa.register = reg
|
|
frame.cfa.offset = offset * frame.dataAlignment
|
|
}
|
|
|
|
func defcfaoffsetsf(frame *FrameContext) {
|
|
offset, _ := util.DecodeSLEB128(frame.buf)
|
|
offset *= frame.dataAlignment
|
|
frame.cfa.offset = offset
|
|
}
|
|
|
|
func defcfaexpression(frame *FrameContext) {
|
|
var (
|
|
l, _ = util.DecodeULEB128(frame.buf)
|
|
expr = frame.buf.Next(int(l))
|
|
)
|
|
|
|
frame.cfa.expression = expr
|
|
frame.cfa.rule = rule_expression
|
|
}
|
|
|
|
func expression(frame *FrameContext) {
|
|
var (
|
|
reg, _ = util.DecodeULEB128(frame.buf)
|
|
l, _ = util.DecodeULEB128(frame.buf)
|
|
expr = frame.buf.Next(int(l))
|
|
)
|
|
|
|
frame.regs[reg] = DWRule{rule: rule_expression, expression: expr}
|
|
}
|
|
|
|
func offsetextendedsf(frame *FrameContext) {
|
|
var (
|
|
reg, _ = util.DecodeULEB128(frame.buf)
|
|
offset, _ = util.DecodeSLEB128(frame.buf)
|
|
)
|
|
|
|
frame.regs[reg] = DWRule{offset: offset * frame.dataAlignment, rule: rule_offset}
|
|
}
|
|
|
|
func valoffset(frame *FrameContext) {
|
|
var (
|
|
reg, _ = util.DecodeULEB128(frame.buf)
|
|
offset, _ = util.DecodeULEB128(frame.buf)
|
|
)
|
|
|
|
frame.regs[reg] = DWRule{offset: int64(offset), rule: rule_valoffset}
|
|
}
|
|
|
|
func valoffsetsf(frame *FrameContext) {
|
|
var (
|
|
reg, _ = util.DecodeULEB128(frame.buf)
|
|
offset, _ = util.DecodeSLEB128(frame.buf)
|
|
)
|
|
|
|
frame.regs[reg] = DWRule{offset: offset * frame.dataAlignment, rule: rule_valoffset}
|
|
}
|
|
|
|
func valexpression(frame *FrameContext) {
|
|
var (
|
|
reg, _ = util.DecodeULEB128(frame.buf)
|
|
l, _ = util.DecodeULEB128(frame.buf)
|
|
expr = frame.buf.Next(int(l))
|
|
)
|
|
|
|
frame.regs[reg] = DWRule{rule: rule_valexpression, expression: expr}
|
|
}
|
|
|
|
func louser(frame *FrameContext) {
|
|
frame.buf.Next(1)
|
|
}
|
|
|
|
func hiuser(frame *FrameContext) {
|
|
frame.buf.Next(1)
|
|
}
|