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mirror of https://github.com/golang/go synced 2024-11-15 03:30:37 -07:00
go/usr/austin/ogle/rvalue.go
Austin Clements 155fe7925b Add stack frame support. Architectures are now responsible
for decoding closures.  There is now no notion of a current OS
thread, though that needs to come back in the form of a
current Go thread.  As a result, Process now implements Peek
and Poke and maps them to any stopped OS thread, since they
all share the address space anyways.

R=rsc
APPROVED=rsc
DELTA=322  (310 added, 3 deleted, 9 changed)
OCL=34136
CL=34201
2009-09-01 13:01:37 -07:00

495 lines
9.5 KiB
Go

// Copyright 2009 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 ogle
import (
"eval";
"fmt";
"ptrace";
)
// A RemoteMismatchError occurs when an operation that requires two
// identical remote processes is given different process. For
// example, this occurs when trying to set a pointer in one process to
// point to something in another process.
type RemoteMismatchError string
func (e RemoteMismatchError) String() string {
return string(e);
}
// A maker is a function that converts a remote address into an
// interpreter Value.
type maker func(remote) eval.Value
type remoteValue interface {
addr() remote;
}
// remote represents an address in a remote process.
type remote struct {
base ptrace.Word;
p *Process;
}
func (v remote) Get(size int) uint64 {
// TODO(austin) This variable might temporarily be in a
// register. We could trace the assembly back from the
// current PC, looking for the beginning of the function or a
// call (both of which guarantee that the variable is in
// memory), or an instruction that loads the variable into a
// register.
//
// TODO(austin) If this is a local variable, it might not be
// live at this PC. In fact, because the compiler reuses
// slots, there might even be a different local variable at
// this location right now. A simple solution to both
// problems is to include the range of PC's over which a local
// variable is live in the symbol table.
//
// TODO(austin) We need to prevent the remote garbage
// collector from collecting objects out from under us.
var arr [8]byte;
buf := arr[0:size];
_, err := v.p.Peek(v.base, buf);
if err != nil {
eval.Abort(err);
}
return uint64(v.p.ToWord(buf));
}
func (v remote) Set(size int, x uint64) {
var arr [8]byte;
buf := arr[0:size];
v.p.FromWord(ptrace.Word(x), buf);
_, err := v.p.Poke(v.base, buf);
if err != nil {
eval.Abort(err);
}
}
func (v remote) plus(x ptrace.Word) remote {
return remote{v.base + x, v.p};
}
/*
* Bool
*/
type remoteBool struct {
r remote;
}
func (v remoteBool) String() string {
return fmt.Sprintf("%v", v.Get());
}
func (v remoteBool) Assign(o eval.Value) {
v.Set(o.(eval.BoolValue).Get());
}
func (v remoteBool) Get() bool {
return v.r.Get(1) != 0;
}
func (v remoteBool) Set(x bool) {
if x {
v.r.Set(1, 1);
} else {
v.r.Set(1, 0);
}
}
func (v remoteBool) addr() remote {
return v.r;
}
func mkBool(r remote) eval.Value {
return remoteBool{r};
}
/*
* Uint
*/
type remoteUint struct {
r remote;
size int;
}
func (v remoteUint) String() string {
return fmt.Sprintf("%v", v.Get());
}
func (v remoteUint) Assign(o eval.Value) {
v.Set(o.(eval.UintValue).Get());
}
func (v remoteUint) Get() uint64 {
return v.r.Get(v.size);
}
func (v remoteUint) Set(x uint64) {
v.r.Set(v.size, x);
}
func (v remoteUint) addr() remote {
return v.r;
}
func mkUint8(r remote) eval.Value {
return remoteUint{r, 1};
}
func mkUint16(r remote) eval.Value {
return remoteUint{r, 2};
}
func mkUint32(r remote) eval.Value {
return remoteUint{r, 4};
}
func mkUint64(r remote) eval.Value {
return remoteUint{r, 8};
}
func mkUint(r remote) eval.Value {
return remoteUint{r, r.p.IntSize()};
}
func mkUintptr(r remote) eval.Value {
return remoteUint{r, r.p.PtrSize()};
}
/*
* Int
*/
type remoteInt struct {
r remote;
size int;
}
func (v remoteInt) String() string {
return fmt.Sprintf("%v", v.Get());
}
func (v remoteInt) Assign(o eval.Value) {
v.Set(o.(eval.IntValue).Get());
}
func (v remoteInt) Get() int64 {
return int64(v.r.Get(v.size));
}
func (v remoteInt) Set(x int64) {
v.r.Set(v.size, uint64(x));
}
func (v remoteInt) addr() remote {
return v.r;
}
func mkInt8(r remote) eval.Value {
return remoteInt{r, 1};
}
func mkInt16(r remote) eval.Value {
return remoteInt{r, 2};
}
func mkInt32(r remote) eval.Value {
return remoteInt{r, 4};
}
func mkInt64(r remote) eval.Value {
return remoteInt{r, 8};
}
func mkInt(r remote) eval.Value {
return remoteInt{r, r.p.IntSize()};
}
/*
* Float
*/
type remoteFloat struct {
r remote;
size int;
}
func (v remoteFloat) String() string {
return fmt.Sprintf("%v", v.Get());
}
func (v remoteFloat) Assign(o eval.Value) {
v.Set(o.(eval.FloatValue).Get());
}
func (v remoteFloat) Get() float64 {
bits := v.r.Get(v.size);
switch v.size {
case 4:
return float64(v.r.p.ToFloat32(uint32(bits)));
case 8:
return v.r.p.ToFloat64(bits);
}
panic("Unexpected float size ", v.size);
}
func (v remoteFloat) Set(x float64) {
var bits uint64;
switch v.size{
case 4:
bits = uint64(v.r.p.FromFloat32(float32(x)));
case 8:
bits = v.r.p.FromFloat64(x);
default:
panic("Unexpected float size ", v.size);
}
v.r.Set(v.size, bits);
}
func (v remoteFloat) addr() remote {
return v.r;
}
func mkFloat32(r remote) eval.Value {
return remoteFloat{r, 4};
}
func mkFloat64(r remote) eval.Value {
return remoteFloat{r, 8};
}
func mkFloat(r remote) eval.Value {
return remoteFloat{r, r.p.FloatSize()};
}
/*
* String
*/
type remoteString struct {
r remote;
}
func (v remoteString) String() string {
return v.Get();
}
func (v remoteString) Assign(o eval.Value) {
v.Set(o.(eval.StringValue).Get());
}
func (v remoteString) Get() string {
rs := v.r.p.runtime.String.mk(v.r).(remoteStruct);
str := ptrace.Word(rs.Field(v.r.p.f.String.Str).(remoteUint).Get());
len := rs.Field(v.r.p.f.String.Len).(remoteInt).Get();
bytes := make([]uint8, len);
_, err := v.r.p.Peek(str, bytes);
if err != nil {
eval.Abort(err);
}
return string(bytes);
}
func (v remoteString) Set(x string) {
// TODO(austin) This isn't generally possible without the
// ability to allocate remote memory.
eval.Abort(RemoteMismatchError("remote strings cannot be assigned to"));
}
func mkString(r remote) eval.Value {
return remoteString{r};
}
/*
* Array
*/
type remoteArray struct {
r remote;
len int64;
elemType *remoteType;
}
func (v remoteArray) String() string {
res := "{";
for i := int64(0); i < v.len; i++ {
if i > 0 {
res += ", ";
}
res += v.Elem(i).String();
}
return res + "}";
}
func (v remoteArray) Assign(o eval.Value) {
// TODO(austin) Could do a bigger memcpy if o is a
// remoteArray in the same Process.
oa := o.(eval.ArrayValue);
for i := int64(0); i < v.len; i++ {
v.Elem(i).Assign(oa.Elem(i));
}
}
func (v remoteArray) Get() eval.ArrayValue {
return v;
}
func (v remoteArray) Elem(i int64) eval.Value {
return v.elemType.mk(v.r.plus(ptrace.Word(int64(v.elemType.size) * i)));
}
func (v remoteArray) From(i int64) eval.ArrayValue {
return remoteArray{v.r.plus(ptrace.Word(int64(v.elemType.size) * i)), v.len - i, v.elemType};
}
/*
* Struct
*/
type remoteStruct struct {
r remote;
layout []remoteStructField;
}
type remoteStructField struct {
offset int;
fieldType *remoteType;
}
func (v remoteStruct) String() string {
res := "{";
for i := range v.layout {
if i > 0 {
res += ", ";
}
res += v.Field(i).String();
}
return res + "}";
}
func (v remoteStruct) Assign(o eval.Value) {
// TODO(austin) Could do a bigger memcpy.
oa := o.(eval.StructValue);
l := len(v.layout);
for i := 0; i < l; i++ {
v.Field(i).Assign(oa.Field(i));
}
}
func (v remoteStruct) Get() eval.StructValue {
return v;
}
func (v remoteStruct) Field(i int) eval.Value {
f := &v.layout[i];
return f.fieldType.mk(v.r.plus(ptrace.Word(f.offset)));
}
func (v remoteStruct) addr() remote {
return v.r;
}
/*
* Pointer
*/
// TODO(austin) Comparing two remote pointers for equality in the
// interpreter will crash it because the Value's returned from
// remotePtr.Get() will be structs.
type remotePtr struct {
r remote;
elemType *remoteType;
}
func (v remotePtr) String() string {
e := v.Get();
if e == nil {
return "<nil>";
}
return "&" + e.String();
}
func (v remotePtr) Assign(o eval.Value) {
v.Set(o.(eval.PtrValue).Get());
}
func (v remotePtr) Get() eval.Value {
addr := ptrace.Word(v.r.Get(v.r.p.PtrSize()));
if addr == 0 {
return nil;
}
return v.elemType.mk(remote{addr, v.r.p});
}
func (v remotePtr) Set(x eval.Value) {
if x == nil {
v.r.Set(v.r.p.PtrSize(), 0);
return;
}
xr, ok := x.(remoteValue);
if !ok || v.r.p != xr.addr().p {
eval.Abort(RemoteMismatchError("remote pointer must point within the same process"));
}
v.r.Set(v.r.p.PtrSize(), uint64(xr.addr().base));
}
func (v remotePtr) addr() remote {
return v.r;
}
/*
* Slice
*/
type remoteSlice struct {
r remote;
elemType *remoteType;
}
func (v remoteSlice) String() string {
b := v.Get().Base;
if b == nil {
return "<nil>";
}
return b.String();
}
func (v remoteSlice) Assign(o eval.Value) {
v.Set(o.(eval.SliceValue).Get());
}
func (v remoteSlice) Get() eval.Slice {
rs := v.r.p.runtime.Slice.mk(v.r).(remoteStruct);
base := ptrace.Word(rs.Field(v.r.p.f.Slice.Array).(remoteUint).Get());
nel := rs.Field(v.r.p.f.Slice.Len).(remoteInt).Get();
cap := rs.Field(v.r.p.f.Slice.Cap).(remoteInt).Get();
if base == 0 {
return eval.Slice{nil, nel, cap};
}
return eval.Slice{remoteArray{remote{base, v.r.p}, nel, v.elemType}, nel, cap};
}
func (v remoteSlice) Set(x eval.Slice) {
rs := v.r.p.runtime.Slice.mk(v.r).(remoteStruct);
if x.Base == nil {
rs.Field(v.r.p.f.Slice.Array).(remoteUint).Set(0);
} else {
ar, ok := x.Base.(remoteArray);
if !ok || v.r.p != ar.r.p {
eval.Abort(RemoteMismatchError("remote slice must point within the same process"));
}
rs.Field(v.r.p.f.Slice.Array).(remoteUint).Set(uint64(ar.r.base));
}
rs.Field(v.r.p.f.Slice.Len).(remoteInt).Set(x.Len);
rs.Field(v.r.p.f.Slice.Cap).(remoteInt).Set(x.Cap);
}