assemblyscript/src/decompiler.ts

889 lines
27 KiB
TypeScript

/**
* A decompiler that generates low-level AssemblyScript from WebAssembly binaries.
* @module decompiler
*//***/
import {
Module,
NativeType,
ExpressionId,
UnaryOp,
BinaryOp,
HostOp,
FunctionRef,
ExpressionRef,
Index,
getFunctionName,
getFunctionBody,
getFunctionParamCount,
getFunctionParamType,
getFunctionResultType,
getExpressionId,
getExpressionType,
getBlockName,
getBlockChildCount,
getBlockChild,
getIfCondition,
getIfTrue,
getIfFalse,
getLoopName,
getLoopBody,
getBreakName,
getBreakCondition,
getGetLocalIndex,
getSetLocalIndex,
getSetLocalValue,
getLoadOffset,
getLoadPtr,
getStoreOffset,
getStorePtr,
getStoreValue,
getConstValueI32,
getConstValueI64Low,
getConstValueI64High,
getConstValueF32,
getConstValueF64,
getUnaryOp,
getUnaryValue,
getBinaryOp,
getBinaryLeft,
getBinaryRight,
getSelectThen,
getSelectElse,
getSelectCondition,
getDropValue,
getReturnValue,
getHostOp,
getHostOperand
} from "./module";
// TODO :-)
export class Decompiler {
static decompile(module: Module): string {
var decompiler = new Decompiler();
decompiler.decompile(module);
return decompiler.finish();
}
text: string[] = [];
functionId: i32 = 0;
constructor() { }
/** Decompiles a module to an AST that can then be serialized. */
decompile(module: Module): void {
throw new Error("not implemented");
}
decompileFunction(func: FunctionRef): void {
var name = getFunctionName(func) || "$" + this.functionId.toString(10);
var body = getFunctionBody(func);
this.push("function ");
this.push(name);
this.push("(");
for (let i: Index = 0, k: Index = getFunctionParamCount(func); i < k; ++i) {
if (i > 0) this.push(", ");
this.push("$");
this.push(i.toString(10));
this.push(": ");
this.push(nativeTypeToType(getFunctionParamType(func, i)));
}
this.push("): ");
this.push(nativeTypeToType(getFunctionResultType(func)));
this.push(" ");
if (getExpressionId(body) != ExpressionId.Block) {
this.push("{\n");
}
this.decompileExpression(body);
if (getExpressionId(body) != ExpressionId.Block) {
this.push("\n}\n");
}
++this.functionId;
}
decompileExpression(expr: ExpressionRef): void {
var id = getExpressionId(expr);
var type = getExpressionType(expr);
var nested: ExpressionRef;
var string: string | null;
var i: Index, k: Index;
switch (id) {
case ExpressionId.Block: { // TODO: magic
if ((string = getBlockName(expr)) != null) {
this.push(string);
this.push(": ");
}
this.push("{\n");
k = getBlockChildCount(expr);
for (i = 0; i < k; ++i) {
this.decompileExpression(getBlockChild(expr, i));
}
this.push("}\n");
return;
}
case ExpressionId.If: {
if (type == NativeType.None) {
this.push("if (");
this.decompileExpression(getIfCondition(expr));
this.push(") ");
this.decompileExpression(getIfTrue(expr));
if (nested = getIfFalse(expr)) {
this.push(" else ");
this.decompileExpression(nested);
}
} else {
this.decompileExpression(getIfCondition(expr));
this.push(" ? ");
this.decompileExpression(getIfTrue(expr));
this.push(" : ");
this.decompileExpression(getIfFalse(expr));
}
return;
}
case ExpressionId.Loop: {
if ((string = getLoopName(expr)) != null) {
this.push(string);
this.push(": ");
}
this.push("do ");
this.decompileExpression(getLoopBody(expr));
this.push("while (0);\n");
}
case ExpressionId.Break: {
if (nested = getBreakCondition(expr)) {
this.push("if (");
this.decompileExpression(nested);
this.push(") ");
}
if ((string = getBreakName(expr)) != null) {
this.push("break ");
this.push(string);
this.push(";\n");
} else {
this.push("break;\n");
}
return;
}
case ExpressionId.Switch:
case ExpressionId.Call:
case ExpressionId.CallImport:
case ExpressionId.CallIndirect: {
throw new Error("not implemented");
}
case ExpressionId.GetLocal: {
this.push("$");
this.push(getGetLocalIndex(expr).toString(10));
return;
}
case ExpressionId.SetLocal: {
this.push("$");
this.push(getSetLocalIndex(expr).toString(10));
this.push(" = ");
this.decompileExpression(getSetLocalValue(expr));
return;
}
case ExpressionId.GetGlobal:
case ExpressionId.SetGlobal: {
throw new Error("not implemented");
}
case ExpressionId.Load: {
this.push("load<");
this.push(nativeTypeToType(type));
this.push(">(");
this.push(getLoadOffset(expr).toString(10));
this.push(" + ");
this.decompileExpression(getLoadPtr(expr));
this.push(")");
return;
}
case ExpressionId.Store: {
this.push("store<");
this.push(nativeTypeToType(type));
this.push(">(");
this.push(getStoreOffset(expr).toString(10));
this.push(" + ");
this.decompileExpression(getStorePtr(expr));
this.push(", ");
this.decompileExpression(getStoreValue(expr));
this.push(")");
return;
}
case ExpressionId.Const: {
switch (type) {
case NativeType.I32: {
this.push(getConstValueI32(expr).toString(10));
return;
}
case NativeType.I64: {
this.push(
i64_to_string(
i64_new(
getConstValueI64Low(expr),
getConstValueI64High(expr)
)
)
);
return;
}
case NativeType.F32: {
this.push(getConstValueF32(expr).toString(10));
return;
}
case NativeType.F64: {
this.push(getConstValueF64(expr).toString(10));
return;
}
}
break;
}
case ExpressionId.Unary: {
switch (getUnaryOp(expr)) {
case UnaryOp.ClzI32: {
this.push("clz<i32>(");
this.decompileExpression(getUnaryValue(expr));
this.push(")");
return;
}
case UnaryOp.CtzI32: {
this.push("ctz<i32>(");
this.decompileExpression(getUnaryValue(expr));
this.push(")");
return;
}
case UnaryOp.PopcntI32: {
this.push("popcnt<i32>(");
this.decompileExpression(getUnaryValue(expr));
this.push(")");
return;
}
case UnaryOp.NegF32:
case UnaryOp.NegF64: {
this.push("-");
this.decompileExpression(getUnaryValue(expr));
return;
}
case UnaryOp.AbsF32: {
this.push("abs<f32>(");
this.decompileExpression(getUnaryValue(expr));
this.push(")");
return;
}
case UnaryOp.CeilF32: {
this.push("ceil<f32>(");
this.decompileExpression(getUnaryValue(expr));
this.push(")");
return;
}
case UnaryOp.FloorF32: {
this.push("floor<f32>(");
this.decompileExpression(getUnaryValue(expr));
this.push(")");
return;
}
case UnaryOp.TruncF32: {
this.push("trunc<f32>(");
this.decompileExpression(getUnaryValue(expr));
this.push(")");
return;
}
case UnaryOp.NearestF32: {
this.push("nearest<i32>(");
this.decompileExpression(getUnaryValue(expr));
this.push(")");
return;
}
case UnaryOp.SqrtF32: {
this.push("sqrt<f32>(");
this.decompileExpression(getUnaryValue(expr));
this.push(")");
return;
}
case UnaryOp.EqzI32:
case UnaryOp.EqzI64: {
this.push("!");
this.decompileExpression(getUnaryValue(expr));
return;
}
case UnaryOp.ClzI64: {
this.push("clz<i64>(");
this.decompileExpression(getUnaryValue(expr));
this.push(")");
return;
}
case UnaryOp.CtzI64: {
this.push("ctz<i64>(");
this.decompileExpression(getUnaryValue(expr));
this.push(")");
return;
}
case UnaryOp.PopcntI64: {
this.push("popcnt<i64>(");
this.decompileExpression(getUnaryValue(expr));
this.push(")");
return;
}
case UnaryOp.AbsF64: {
this.push("abs<f64>(");
this.decompileExpression(getUnaryValue(expr));
this.push(")");
return;
}
case UnaryOp.CeilF64: {
this.push("ceil<f64>(");
this.decompileExpression(getUnaryValue(expr));
this.push(")");
return;
}
case UnaryOp.FloorF64: {
this.push("floor<f64>(");
this.decompileExpression(getUnaryValue(expr));
this.push(")");
return;
}
case UnaryOp.TruncF64: {
this.push("trunc<f64>(");
this.decompileExpression(getUnaryValue(expr));
this.push(")");
return;
}
case UnaryOp.NearestF64: {
this.push("nearest<f64>(");
this.decompileExpression(getUnaryValue(expr));
this.push(")");
return;
}
case UnaryOp.SqrtF64: {
this.push("sqrt<f64>(");
this.decompileExpression(getUnaryValue(expr));
this.push(")");
return;
}
case UnaryOp.ExtendI32: {
this.push("<i64>");
this.decompileExpression(getUnaryValue(expr));
return;
}
case UnaryOp.ExtendU32: {
this.push("<i64><u64>");
this.decompileExpression(getUnaryValue(expr));
return;
}
case UnaryOp.WrapI64: {
this.push("<i32>");
this.decompileExpression(getUnaryValue(expr));
return;
}
case UnaryOp.TruncF32ToI32: {
this.push("<i32>");
this.decompileExpression(getUnaryValue(expr));
return;
}
case UnaryOp.TruncF32ToI64: {
this.push("<i64>");
this.decompileExpression(getUnaryValue(expr));
return;
}
case UnaryOp.TruncF32ToU32: {
this.push("<i32><u32>");
this.decompileExpression(getUnaryValue(expr));
return;
}
case UnaryOp.TruncF32ToU64: {
this.push("<i64><u64>");
this.decompileExpression(getUnaryValue(expr));
return;
}
case UnaryOp.TruncF64ToI32: {
this.push("<i32>");
this.decompileExpression(getUnaryValue(expr));
return;
}
case UnaryOp.TruncF64ToI64: {
this.push("<i64>");
this.decompileExpression(getUnaryValue(expr));
return;
}
case UnaryOp.TruncF64ToU32: {
this.push("<i32><u32>");
this.decompileExpression(getUnaryValue(expr));
return;
}
case UnaryOp.TruncF64ToU64: {
this.push("<i64><u64>");
this.decompileExpression(getUnaryValue(expr));
return;
}
case UnaryOp.ReinterpretF32: {
this.push("reinterpret<f32,i32>(");
this.decompileExpression(getUnaryValue(expr));
this.push(")");
return;
}
case UnaryOp.ReinterpretF64: {
this.push("reinterpret<f64,i64>(");
this.decompileExpression(getUnaryValue(expr));
this.push(")");
return;
}
case UnaryOp.ConvertI32ToF32: {
this.push("<f32>");
this.decompileExpression(getUnaryValue(expr));
return;
}
case UnaryOp.ConvertI32ToF64: {
this.push("<f64>");
this.decompileExpression(getUnaryValue(expr));
return;
}
case UnaryOp.ConvertU32ToF32: {
this.push("<f32><u32>");
this.decompileExpression(getUnaryValue(expr));
return;
}
case UnaryOp.ConvertU32ToF64: {
this.push("<f64><u32>");
this.decompileExpression(getUnaryValue(expr));
return;
}
case UnaryOp.ConvertI64ToF32: {
this.push("<f32>");
this.decompileExpression(getUnaryValue(expr));
return;
}
case UnaryOp.ConvertI64ToF64: {
this.push("<f64>");
this.decompileExpression(getUnaryValue(expr));
return;
}
case UnaryOp.ConvertU64ToF32: {
this.push("<f32><u64>");
this.decompileExpression(getUnaryValue(expr));
return;
}
case UnaryOp.ConvertU64ToF64: {
this.push("<f64><u64>");
this.decompileExpression(getUnaryValue(expr));
return;
}
case UnaryOp.PromoteF32: {
this.push("<f64>");
this.decompileExpression(getUnaryValue(expr));
return;
}
case UnaryOp.DemoteF64: {
this.push("<f32>");
this.decompileExpression(getUnaryValue(expr));
return;
}
case UnaryOp.ReinterpretI32: {
this.push("reinterpret<i32,f32>(");
this.decompileExpression(getUnaryValue(expr));
this.push(")");
return;
}
case UnaryOp.ReinterpretI64: {
this.push("reinterpret<i64,f64>(");
this.decompileExpression(getUnaryValue(expr));
this.push(")");
return;
}
}
break;
}
case ExpressionId.Binary: { // TODO: precedence
switch (getBinaryOp(expr)) {
case BinaryOp.AddI32:
case BinaryOp.AddI64:
case BinaryOp.AddF32:
case BinaryOp.AddF64: {
this.decompileExpression(getBinaryLeft(expr));
this.push(" + ");
this.decompileExpression(getBinaryRight(expr));
return;
}
case BinaryOp.SubI32:
case BinaryOp.SubI64:
case BinaryOp.SubF32:
case BinaryOp.SubF64: {
this.decompileExpression(getBinaryLeft(expr));
this.push(" - ");
this.decompileExpression(getBinaryRight(expr));
return;
}
case BinaryOp.MulI32:
case BinaryOp.MulI64:
case BinaryOp.MulF32:
case BinaryOp.MulF64: {
this.decompileExpression(getBinaryLeft(expr));
this.push(" * ");
this.decompileExpression(getBinaryRight(expr));
return;
}
case BinaryOp.DivI32:
case BinaryOp.DivI64:
case BinaryOp.DivF32:
case BinaryOp.DivF64: {
this.decompileExpression(getBinaryLeft(expr));
this.push(" / ");
this.decompileExpression(getBinaryRight(expr));
return;
}
case BinaryOp.DivU32: {
this.push("<i32>(<u32>");
this.decompileExpression(getBinaryLeft(expr));
this.push(" / <u32>");
this.decompileExpression(getBinaryRight(expr));
this.push(")");
return;
}
case BinaryOp.RemI32:
case BinaryOp.RemI64: {
this.decompileExpression(getBinaryLeft(expr));
this.push(" % ");
this.decompileExpression(getBinaryRight(expr));
return;
}
case BinaryOp.RemU32: {
this.push("<i32>(<u32>");
this.decompileExpression(getBinaryLeft(expr));
this.push(" / <u32>");
this.decompileExpression(getBinaryRight(expr));
this.push(")");
return;
}
case BinaryOp.AndI32:
case BinaryOp.AndI64: {
this.decompileExpression(getBinaryLeft(expr));
this.push(" & ");
this.decompileExpression(getBinaryRight(expr));
return;
}
case BinaryOp.OrI32:
case BinaryOp.OrI64: {
this.decompileExpression(getBinaryLeft(expr));
this.push(" | ");
this.decompileExpression(getBinaryRight(expr));
return;
}
case BinaryOp.XorI32:
case BinaryOp.XorI64: {
this.decompileExpression(getBinaryLeft(expr));
this.push(" ^ ");
this.decompileExpression(getBinaryRight(expr));
return;
}
case BinaryOp.ShlI32:
case BinaryOp.ShlI64: {
this.decompileExpression(getBinaryLeft(expr));
this.push(" << ");
this.decompileExpression(getBinaryRight(expr));
return;
}
case BinaryOp.ShrU32:
case BinaryOp.ShrU64: {
this.decompileExpression(getBinaryLeft(expr));
this.push(" >>> ");
this.decompileExpression(getBinaryRight(expr));
return;
}
case BinaryOp.ShrI32:
case BinaryOp.ShrI64: {
this.decompileExpression(getBinaryLeft(expr));
this.push(" >> ");
this.decompileExpression(getBinaryRight(expr));
return;
}
case BinaryOp.RotlI32: {
this.push("rotl<i32>(");
this.decompileExpression(getBinaryLeft(expr));
this.push(", ");
this.decompileExpression(getBinaryRight(expr));
this.push(")");
return;
}
case BinaryOp.RotrI32: {
this.push("rotr<i32>(");
this.decompileExpression(getBinaryLeft(expr));
this.push(", ");
this.decompileExpression(getBinaryRight(expr));
this.push(")");
return;
}
case BinaryOp.EqI32:
case BinaryOp.EqI64:
case BinaryOp.EqF32:
case BinaryOp.EqF64: {
this.decompileExpression(getBinaryLeft(expr));
this.push(" == ");
this.decompileExpression(getBinaryRight(expr));
return;
}
case BinaryOp.NeI32:
case BinaryOp.NeI64:
case BinaryOp.NeF32:
case BinaryOp.NeF64: {
this.decompileExpression(getBinaryLeft(expr));
this.push(" != ");
this.decompileExpression(getBinaryRight(expr));
return;
}
case BinaryOp.LtI32:
case BinaryOp.LtI64:
case BinaryOp.LtF32:
case BinaryOp.LtF64: {
this.decompileExpression(getBinaryLeft(expr));
this.push(" < ");
this.decompileExpression(getBinaryRight(expr));
return;
}
case BinaryOp.LtU32: {
this.push("<u32>");
this.decompileExpression(getBinaryLeft(expr));
this.push(" < <u32>");
this.decompileExpression(getBinaryRight(expr));
return;
}
case BinaryOp.LeI32:
case BinaryOp.LeI64:
case BinaryOp.LeF32:
case BinaryOp.LeF64: {
this.decompileExpression(getBinaryLeft(expr));
this.push(" <= ");
this.decompileExpression(getBinaryRight(expr));
return;
}
case BinaryOp.LeU32: {
this.push("<u32>");
this.decompileExpression(getBinaryLeft(expr));
this.push(" <= <u32>");
this.decompileExpression(getBinaryRight(expr));
return;
}
case BinaryOp.GtI32:
case BinaryOp.GtI64:
case BinaryOp.GtF32:
case BinaryOp.GtF64: {
this.decompileExpression(getBinaryLeft(expr));
this.push(" > ");
this.decompileExpression(getBinaryRight(expr));
return;
}
case BinaryOp.GtU32: {
this.push("<u32>");
this.decompileExpression(getBinaryLeft(expr));
this.push(" > <u32>");
this.decompileExpression(getBinaryRight(expr));
return;
}
case BinaryOp.GeI32:
case BinaryOp.GeI64:
case BinaryOp.GeF32:
case BinaryOp.GeF64: {
this.decompileExpression(getBinaryLeft(expr));
this.push(" >= ");
this.decompileExpression(getBinaryRight(expr));
return;
}
case BinaryOp.GeU32: {
this.push("<u32>");
this.decompileExpression(getBinaryLeft(expr));
this.push(" >= <u32>");
this.decompileExpression(getBinaryRight(expr));
return;
}
case BinaryOp.DivU64: {
this.push("<u64>");
this.decompileExpression(getBinaryLeft(expr));
this.push(" / <u64>");
this.decompileExpression(getBinaryRight(expr));
return;
}
case BinaryOp.RemU64: {
this.push("<u64>");
this.decompileExpression(getBinaryLeft(expr));
this.push(" % <u64>");
this.decompileExpression(getBinaryRight(expr));
return;
}
case BinaryOp.RotlI64: {
this.push("rotl<i64>(");
this.decompileExpression(getBinaryLeft(expr));
this.push(", ");
this.decompileExpression(getBinaryRight(expr));
this.push(")");
return;
}
case BinaryOp.RotrI64: {
this.push("rotr<i64>(");
this.decompileExpression(getBinaryLeft(expr));
this.push(", ");
this.decompileExpression(getBinaryRight(expr));
this.push(")");
return;
}
case BinaryOp.LtU64: {
this.push("<u64>");
this.decompileExpression(getBinaryLeft(expr));
this.push(" < <u64>");
this.decompileExpression(getBinaryRight(expr));
return;
}
case BinaryOp.LeU64: {
this.push("<u64>");
this.decompileExpression(getBinaryLeft(expr));
this.push(" <= <u64>");
this.decompileExpression(getBinaryRight(expr));
return;
}
case BinaryOp.GtU64: {
this.push("<u64>");
this.decompileExpression(getBinaryLeft(expr));
this.push(" > <u64>");
this.decompileExpression(getBinaryRight(expr));
return;
}
case BinaryOp.GeU64: {
this.push("<u64>");
this.decompileExpression(getBinaryLeft(expr));
this.push(" >= <u64>");
this.decompileExpression(getBinaryRight(expr));
return;
}
case BinaryOp.CopysignF32: {
this.push("copysign<f32>(");
this.decompileExpression(getBinaryLeft(expr));
this.push(", ");
this.decompileExpression(getBinaryRight(expr));
this.push(")");
return;
}
case BinaryOp.MinF32: {
this.push("min<f32>(");
this.decompileExpression(getBinaryLeft(expr));
this.push(", ");
this.decompileExpression(getBinaryRight(expr));
this.push(")");
return;
}
case BinaryOp.MaxF32: {
this.push("max<f32>(");
this.decompileExpression(getBinaryLeft(expr));
this.push(", ");
this.decompileExpression(getBinaryRight(expr));
this.push(")");
return;
}
case BinaryOp.CopysignF64: {
this.push("copysign<f64>(");
this.decompileExpression(getBinaryLeft(expr));
this.push(", ");
this.decompileExpression(getBinaryRight(expr));
this.push(")");
return;
}
case BinaryOp.MinF64: {
this.push("min<f64>(");
this.decompileExpression(getBinaryLeft(expr));
this.push(", ");
this.decompileExpression(getBinaryRight(expr));
this.push(")");
return;
}
case BinaryOp.MaxF64: {
this.push("max<f64>(");
this.decompileExpression(getBinaryLeft(expr));
this.push(", ");
this.decompileExpression(getBinaryRight(expr));
this.push(")");
return;
}
}
return;
}
case ExpressionId.Select: {
this.push("select<");
this.push(nativeTypeToType(type));
this.push(">(");
this.decompileExpression(getSelectThen(expr));
this.push(", ");
this.decompileExpression(getSelectElse(expr));
this.push(", ");
this.decompileExpression(getSelectCondition(expr));
this.push(")");
return;
}
case ExpressionId.Drop: {
this.decompileExpression(getDropValue(expr));
this.push(";\n");
return;
}
case ExpressionId.Return: {
if (nested = getReturnValue(expr)) {
this.push("return ");
this.decompileExpression(nested);
this.push(";\n");
} else {
this.push("return;\n");
}
return;
}
case ExpressionId.Host: {
switch (getHostOp(expr)) {
case HostOp.CurrentMemory: {
this.push("current_memory()");
return;
}
case HostOp.GrowMemory: {
this.push("grow_memory(");
this.decompileExpression(getHostOperand(expr, 0));
this.push(")");
return;
}
}
break;
}
case ExpressionId.Nop: {
this.push(";\n");
return;
}
case ExpressionId.Unreachable: {
this.push("unreachable()");
return;
}
case ExpressionId.AtomicCmpxchg:
case ExpressionId.AtomicRMW:
case ExpressionId.AtomicWait:
case ExpressionId.AtomicWake:
}
throw new Error("not implemented");
}
private push(text: string): void {
// mostly here so we can add debugging if necessary
this.text.push(text);
}
finish(): string {
var ret = this.text.join("");
this.text = [];
return ret;
}
}
function nativeTypeToType(type: NativeType): string {
switch (type) {
case NativeType.None: return "void";
case NativeType.I32: return "i32";
case NativeType.I64: return "i64";
case NativeType.F32: return "f32";
case NativeType.F64: return "f64";
case NativeType.Unreachable: throw new Error("unreachable type");
case NativeType.Auto: throw new Error("auto type");
default: throw new Error("unexpected type");
}
}