gotosocial/vendor/github.com/chenzhuoyu/iasm/x86_64/program.go

569 lines
12 KiB
Go
Raw Normal View History

package x86_64
import (
"fmt"
"math"
"math/bits"
"github.com/chenzhuoyu/iasm/expr"
)
type (
_PseudoType int
_InstructionEncoder func(*Program, ...interface{}) *Instruction
)
const (
_PseudoNop _PseudoType = iota + 1
_PseudoByte
_PseudoWord
_PseudoLong
_PseudoQuad
_PseudoData
_PseudoAlign
)
func (self _PseudoType) String() string {
switch self {
case _PseudoNop:
return ".nop"
case _PseudoByte:
return ".byte"
case _PseudoWord:
return ".word"
case _PseudoLong:
return ".long"
case _PseudoQuad:
return ".quad"
case _PseudoData:
return ".data"
case _PseudoAlign:
return ".align"
default:
panic("unreachable")
}
}
type _Pseudo struct {
kind _PseudoType
data []byte
uint uint64
expr *expr.Expr
}
func (self *_Pseudo) free() {
if self.expr != nil {
self.expr.Free()
}
}
func (self *_Pseudo) encode(m *[]byte, pc uintptr) int {
switch self.kind {
case _PseudoNop:
return 0
case _PseudoByte:
self.encodeByte(m)
return 1
case _PseudoWord:
self.encodeWord(m)
return 2
case _PseudoLong:
self.encodeLong(m)
return 4
case _PseudoQuad:
self.encodeQuad(m)
return 8
case _PseudoData:
self.encodeData(m)
return len(self.data)
case _PseudoAlign:
self.encodeAlign(m, pc)
return self.alignSize(pc)
default:
panic("invalid pseudo instruction")
}
}
func (self *_Pseudo) evalExpr(low int64, high int64) int64 {
if v, err := self.expr.Evaluate(); err != nil {
panic(err)
} else if v < low || v > high {
panic(fmt.Sprintf("expression out of range [%d, %d]: %d", low, high, v))
} else {
return v
}
}
func (self *_Pseudo) alignSize(pc uintptr) int {
if !ispow2(self.uint) {
panic(fmt.Sprintf("aligment should be a power of 2, not %d", self.uint))
} else {
return align(int(pc), bits.TrailingZeros64(self.uint)) - int(pc)
}
}
func (self *_Pseudo) encodeData(m *[]byte) {
if m != nil {
*m = append(*m, self.data...)
}
}
func (self *_Pseudo) encodeByte(m *[]byte) {
if m != nil {
append8(m, byte(self.evalExpr(math.MinInt8, math.MaxUint8)))
}
}
func (self *_Pseudo) encodeWord(m *[]byte) {
if m != nil {
append16(m, uint16(self.evalExpr(math.MinInt16, math.MaxUint16)))
}
}
func (self *_Pseudo) encodeLong(m *[]byte) {
if m != nil {
append32(m, uint32(self.evalExpr(math.MinInt32, math.MaxUint32)))
}
}
func (self *_Pseudo) encodeQuad(m *[]byte) {
if m != nil {
if v, err := self.expr.Evaluate(); err != nil {
panic(err)
} else {
append64(m, uint64(v))
}
}
}
func (self *_Pseudo) encodeAlign(m *[]byte, pc uintptr) {
if m != nil {
if self.expr == nil {
expandmm(m, self.alignSize(pc), 0)
} else {
expandmm(m, self.alignSize(pc), byte(self.evalExpr(math.MinInt8, math.MaxUint8)))
}
}
}
// Operands represents a sequence of operand required by an instruction.
type Operands [_N_args]interface{}
// InstructionDomain represents the domain of an instruction.
type InstructionDomain uint8
const (
DomainGeneric InstructionDomain = iota
DomainMMXSSE
DomainAVX
DomainFMA
DomainCrypto
DomainMask
DomainAMDSpecific
DomainMisc
DomainPseudo
)
type (
_BranchType uint8
)
const (
_B_none _BranchType = iota
_B_conditional
_B_unconditional
)
// Instruction represents an unencoded instruction.
type Instruction struct {
next *Instruction
pc uintptr
nb int
len int
argc int
name string
argv Operands
forms [_N_forms]_Encoding
pseudo _Pseudo
branch _BranchType
domain InstructionDomain
prefix []byte
}
func (self *Instruction) add(flags int, encoder func(m *_Encoding, v []interface{})) {
self.forms[self.len].flags = flags
self.forms[self.len].encoder = encoder
self.len++
}
func (self *Instruction) free() {
self.clear()
self.pseudo.free()
//freeInstruction(self)
}
func (self *Instruction) clear() {
for i := 0; i < self.argc; i++ {
if v, ok := self.argv[i].(Disposable); ok {
v.Free()
}
}
}
func (self *Instruction) check(e *_Encoding) bool {
if (e.flags & _F_rel1) != 0 {
return isRel8(self.argv[0])
} else if (e.flags & _F_rel4) != 0 {
return isRel32(self.argv[0]) || isLabel(self.argv[0])
} else {
return true
}
}
func (self *Instruction) encode(m *[]byte) int {
n := math.MaxInt64
p := (*_Encoding)(nil)
/* encode prefixes if any */
if self.nb = len(self.prefix); m != nil {
*m = append(*m, self.prefix...)
}
/* check for pseudo-instructions */
if self.pseudo.kind != 0 {
self.nb += self.pseudo.encode(m, self.pc)
return self.nb
}
/* find the shortest encoding */
for i := 0; i < self.len; i++ {
if e := &self.forms[i]; self.check(e) {
if v := e.encode(self.argv[:self.argc]); v < n {
n = v
p = e
}
}
}
/* add to buffer if needed */
if m != nil {
*m = append(*m, p.bytes[:n]...)
}
/* update the instruction length */
self.nb += n
return self.nb
}
/** Instruction Prefixes **/
const (
_P_cs = 0x2e
_P_ds = 0x3e
_P_es = 0x26
_P_fs = 0x64
_P_gs = 0x65
_P_ss = 0x36
_P_lock = 0xf0
)
// CS overrides the memory operation of this instruction to CS.
func (self *Instruction) CS() *Instruction {
self.prefix = append(self.prefix, _P_cs)
return self
}
// DS overrides the memory operation of this instruction to DS,
// this is the default section for most instructions if not specified.
func (self *Instruction) DS() *Instruction {
self.prefix = append(self.prefix, _P_ds)
return self
}
// ES overrides the memory operation of this instruction to ES.
func (self *Instruction) ES() *Instruction {
self.prefix = append(self.prefix, _P_es)
return self
}
// FS overrides the memory operation of this instruction to FS.
func (self *Instruction) FS() *Instruction {
self.prefix = append(self.prefix, _P_fs)
return self
}
// GS overrides the memory operation of this instruction to GS.
func (self *Instruction) GS() *Instruction {
self.prefix = append(self.prefix, _P_gs)
return self
}
// SS overrides the memory operation of this instruction to SS.
func (self *Instruction) SS() *Instruction {
self.prefix = append(self.prefix, _P_ss)
return self
}
// LOCK causes the processor's LOCK# signal to be asserted during execution of
// the accompanying instruction (turns the instruction into an atomic instruction).
// In a multiprocessor environment, the LOCK# signal insures that the processor
// has exclusive use of any shared memory while the signal is asserted.
func (self *Instruction) LOCK() *Instruction {
self.prefix = append(self.prefix, _P_lock)
return self
}
/** Basic Instruction Properties **/
// Name returns the instruction name.
func (self *Instruction) Name() string {
return self.name
}
// Domain returns the domain of this instruction.
func (self *Instruction) Domain() InstructionDomain {
return self.domain
}
// Operands returns the operands of this instruction.
func (self *Instruction) Operands() []interface{} {
return self.argv[:self.argc]
}
// Program represents a sequence of instructions.
type Program struct {
arch *Arch
head *Instruction
tail *Instruction
}
const (
_N_near = 2 // near-branch (-128 ~ +127) takes 2 bytes to encode
_N_far_cond = 6 // conditional far-branch takes 6 bytes to encode
_N_far_uncond = 5 // unconditional far-branch takes 5 bytes to encode
)
func (self *Program) clear() {
for p, q := self.head, self.head; p != nil; p = q {
q = p.next
p.free()
}
}
func (self *Program) alloc(name string, argc int, argv Operands) *Instruction {
p := self.tail
q := newInstruction(name, argc, argv)
/* attach to tail if any */
if p != nil {
p.next = q
} else {
self.head = q
}
/* set the new tail */
self.tail = q
return q
}
func (self *Program) pseudo(kind _PseudoType) (p *Instruction) {
p = self.alloc(kind.String(), 0, Operands{})
p.domain = DomainPseudo
p.pseudo.kind = kind
return
}
func (self *Program) require(isa ISA) {
if !self.arch.HasISA(isa) {
panic("ISA '" + isa.String() + "' was not enabled")
}
}
func (self *Program) branchSize(p *Instruction) int {
switch p.branch {
case _B_none:
panic("p is not a branch")
case _B_conditional:
return _N_far_cond
case _B_unconditional:
return _N_far_uncond
default:
panic("invalid instruction")
}
}
/** Pseudo-Instructions **/
// Byte is a pseudo-instruction to add raw byte to the assembled code.
func (self *Program) Byte(v *expr.Expr) (p *Instruction) {
p = self.pseudo(_PseudoByte)
p.pseudo.expr = v
return
}
// Word is a pseudo-instruction to add raw uint16 as little-endian to the assembled code.
func (self *Program) Word(v *expr.Expr) (p *Instruction) {
p = self.pseudo(_PseudoWord)
p.pseudo.expr = v
return
}
// Long is a pseudo-instruction to add raw uint32 as little-endian to the assembled code.
func (self *Program) Long(v *expr.Expr) (p *Instruction) {
p = self.pseudo(_PseudoLong)
p.pseudo.expr = v
return
}
// Quad is a pseudo-instruction to add raw uint64 as little-endian to the assembled code.
func (self *Program) Quad(v *expr.Expr) (p *Instruction) {
p = self.pseudo(_PseudoQuad)
p.pseudo.expr = v
return
}
// Data is a pseudo-instruction to add raw bytes to the assembled code.
func (self *Program) Data(v []byte) (p *Instruction) {
p = self.pseudo(_PseudoData)
p.pseudo.data = v
return
}
// Align is a pseudo-instruction to ensure the PC is aligned to a certain value.
func (self *Program) Align(align uint64, padding *expr.Expr) (p *Instruction) {
p = self.pseudo(_PseudoAlign)
p.pseudo.uint = align
p.pseudo.expr = padding
return
}
/** Program Assembler **/
// Free returns the Program object into pool.
// Any operation performed after Free is undefined behavior.
//
// NOTE: This also frees all the instructions, labels, memory
//
// operands and expressions associated with this program.
func (self *Program) Free() {
self.clear()
//freeProgram(self)
}
// Link pins a label at the current position.
func (self *Program) Link(p *Label) {
if p.Dest != nil {
panic("lable was alreay linked")
} else {
p.Dest = self.pseudo(_PseudoNop)
}
}
// Assemble assembles and links the entire program into machine code.
func (self *Program) Assemble(pc uintptr) (ret []byte) {
orig := pc
next := true
offs := uintptr(0)
/* Pass 0: PC-precompute, assume all labeled branches are far-branches. */
for p := self.head; p != nil; p = p.next {
if p.pc = pc; !isLabel(p.argv[0]) || p.branch == _B_none {
pc += uintptr(p.encode(nil))
} else {
pc += uintptr(self.branchSize(p))
}
}
/* allocate space for the machine code */
nb := int(pc - orig)
ret = make([]byte, 0, nb)
/* Pass 1: adjust all the jumps */
for next {
next = false
offs = uintptr(0)
/* scan all the branches */
for p := self.head; p != nil; p = p.next {
var ok bool
var lb *Label
/* re-calculate the alignment here */
if nb = p.nb; p.pseudo.kind == _PseudoAlign {
p.pc -= offs
offs += uintptr(nb - p.encode(nil))
continue
}
/* adjust the program counter */
p.pc -= offs
lb, ok = p.argv[0].(*Label)
/* only care about labeled far-branches */
if !ok || p.nb == _N_near || p.branch == _B_none {
continue
}
/* calculate the jump offset */
size := self.branchSize(p)
diff := lb.offset(p.pc, size)
/* too far to be a near jump */
if diff > 127 || diff < -128 {
p.nb = size
continue
}
/* a far jump becomes a near jump, calculate
* the PC adjustment value and assemble again */
next = true
p.nb = _N_near
offs += uintptr(size - _N_near)
}
}
/* Pass 3: link all the cross-references */
for p := self.head; p != nil; p = p.next {
for i := 0; i < p.argc; i++ {
var ok bool
var lb *Label
var op *MemoryOperand
/* resolve labels */
if lb, ok = p.argv[i].(*Label); ok {
p.argv[i] = lb.offset(p.pc, p.nb)
continue
}
/* check for memory operands */
if op, ok = p.argv[i].(*MemoryOperand); !ok {
continue
}
/* check for label references */
if op.Addr.Type != Reference {
continue
}
/* replace the label with the real offset */
op.Addr.Type = Offset
op.Addr.Offset = op.Addr.Reference.offset(p.pc, p.nb)
}
}
/* Pass 4: actually encode all the instructions */
for p := self.head; p != nil; p = p.next {
p.encode(&ret)
}
/* all done */
return ret
}
// AssembleAndFree is like Assemble, but it frees the Program after assembling.
func (self *Program) AssembleAndFree(pc uintptr) (ret []byte) {
ret = self.Assemble(pc)
self.Free()
return
}