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Copy pathExprCompile.cs
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524 lines (520 loc) · 23.9 KB
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using System;
using System.Reflection;
using System.Collections.Generic;
using UnityEngine;
using Microsoft.Z3;
namespace UnityActionAnalysis
{
public static class ExprCompile
{
public static Func<ExprContext, object> ResolveValue(SymexValue value, SymexPath p)
{
switch (value.GetValueType())
{
case SymexValueType.StringConstant:
{
SymexStringConstantValue sv = (SymexStringConstantValue)value;
string s = sv.value;
return ctx => s;
}
case SymexValueType.BitVecConstant:
{
SymexBitVecConstantValue bv = (SymexBitVecConstantValue)value;
ulong v = bv.value;
return ctx => v;
}
case SymexValueType.Object:
{
throw new ResolutionException("object resolution not yet implemented");
}
case SymexValueType.Variable:
{
SymexVariableValue vv = (SymexVariableValue)value;
return ResolveVariable(vv.varName, p);
}
case SymexValueType.Struct:
{
SymexStructValue sval = (SymexStructValue)value;
Type type = sval.structType;
var ctor = type.GetConstructor(new Type[0]);
Dictionary<FieldInfo, Func<ExprContext, object>> fields = new Dictionary<FieldInfo, Func<ExprContext, object>>();
foreach (var kv in sval.value)
{
var fieldName = kv.Key;
var field = type.GetField(fieldName, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
var fieldVal = ResolveValue(kv.Value, p);
fields.Add(field, fieldVal);
}
return ctx =>
{
object result = ctor.Invoke(new object[0]);
foreach (var kv in fields)
{
var field = kv.Key;
var val = kv.Value;
field.SetValue(result, val(ctx));
}
return result;
};
}
case SymexValueType.UnevaluatedMethodCall:
{
SymexUnevaluatedMethodCallValue mval = (SymexUnevaluatedMethodCallValue)value;
List<Func<ExprContext, object>> args = new List<Func<ExprContext, object>>();
for (int i = 0; i < mval.arguments.Count; ++i)
{
args.Add(ResolveValue(mval.arguments[i], p));
}
if (mval.method.IsStatic)
{
return ctx =>
{
object[] argVals = new object[args.Count];
for (int i = 0; i < args.Count; ++i)
{
argVals[i] = args[i](ctx);
}
return mval.method.Invoke(null, argVals);
};
} else
{
return ctx =>
{
object thisVal = args[0](ctx);
object[] argVals = new object[args.Count - 1];
for (int i = 1; i < args.Count; ++i)
{
argVals[i - 1] = args[i](ctx);
}
return mval.method.Invoke(thisVal, argVals);
};
}
}
default:
throw new Exception("unexpected value type " + value.GetValueType());
}
}
public static Func<ExprContext, object> ResolveSymcall(Symcall sc, SymexPath p)
{
List<Func<ExprContext, object>> args = new List<Func<ExprContext, object>>();
for (int i = 0, n = sc.args.Count; i < n; ++i)
{
args.Add(ResolveValue(sc.args[i], p));
}
if (sc.method.IsStatic)
{
return ctx =>
{
object[] argVals = new object[args.Count];
for (int i = 0; i < args.Count; ++i)
{
argVals[i] = args[i](ctx);
}
return sc.method.Invoke(null, argVals);
};
}
else
{
return ctx =>
{
object thisVal = args[0](ctx);
object[] argVals = new object[args.Count - 1];
for (int i = 1; i < args.Count; ++i)
{
argVals[i - 1] = args[i](ctx);
}
return sc.method.Invoke(thisVal, argVals);
};
}
}
public static Func<ExprContext, object> ResolveVariable(string varName, SymexPath p)
{
SymexMethod m = p.Method;
string[] parts = varName.Split(':');
bool staticField;
if ((staticField = varName.StartsWith("staticfield:")) || varName.StartsWith("frame:0:this:instancefield:"))
{
List<FieldInfo> fieldAccesses = new List<FieldInfo>();
int idx;
if (staticField)
{
string field = parts[1];
int dotIndex = field.LastIndexOf('.');
string typeName = field.Substring(0, dotIndex);
string fieldName = field.Substring(dotIndex + 1);
Type type = Type.GetType(typeName);
FieldInfo f = type.GetField(fieldName, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Static);
fieldAccesses.Add(f);
idx = 2;
}
else
{
string fieldName = parts[4];
Type instanceType = m.method.DeclaringType;
FieldInfo f = instanceType.GetField(fieldName, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
fieldAccesses.Add(f);
idx = 5;
}
while (idx < parts.Length)
{
var lastField = fieldAccesses[fieldAccesses.Count - 1];
if (parts[idx] == "instancefield")
{
string fieldName = parts[idx + 1];
Type type = lastField.FieldType;
FieldInfo f = type.GetField(fieldName, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
fieldAccesses.Add(f);
idx += 2;
} else
{
throw new Exception("expected instancefield, got " + parts[idx]);
}
}
return ctx =>
{
object value = ctx.instance;
foreach (FieldInfo f in fieldAccesses)
{
if (value == null)
{
throw new ResolutionException("null pointer dereference when evaluating " + varName);
}
value = f.GetValue(value);
}
return value;
};
} else if (varName.StartsWith("symcall:"))
{
int symcallId = int.Parse(parts[1]);
List<FieldInfo> fieldAccesses = new List<FieldInfo>();
Symcall sc = p.symcalls[symcallId];
Type currType = sc.method.ReturnType;
var symcall = ResolveSymcall(sc, p);
int idx = 2;
while (idx < parts.Length)
{
if (parts[idx] == "instancefield")
{
string fieldName = parts[idx + 1];
FieldInfo f = currType.GetField(fieldName, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
fieldAccesses.Add(f);
currType = f.FieldType;
idx += 2;
}
else
{
throw new Exception("expected instancefield, got " + parts[idx]);
}
}
return ctx =>
{
object value = symcall(ctx);
foreach (FieldInfo f in fieldAccesses)
{
if (value == null)
{
throw new ResolutionException("null pointer dereference when evaluating " + varName);
}
value = f.GetValue(value);
}
return value;
};
} else
{
throw new ResolutionException("cannot resolve variable " + varName);
}
}
public static Func<ExprContext, object> Compile(Expr expr, SymexPath p)
{
switch (expr.FuncDecl.DeclKind)
{
case Z3_decl_kind.Z3_OP_NOT:
{
var val = Compile(expr.Arg(0), p);
return ctx => !CompileHelpers.ToBool(val(ctx));
}
case Z3_decl_kind.Z3_OP_AND:
{
if (expr.NumArgs > 2)
{
throw new ResolutionException("more than 2 args not supported in and expression");
}
var val1 = Compile(expr.Arg(0), p);
var val2 = Compile(expr.Arg(1), p);
return ctx => CompileHelpers.ToBool(val1(ctx)) && CompileHelpers.ToBool(val2(ctx));
}
case Z3_decl_kind.Z3_OP_OR:
{
if (expr.NumArgs > 2)
{
throw new ResolutionException("more than 2 args not supported in or expression");
}
var val1 = Compile(expr.Arg(0), p);
var val2 = Compile(expr.Arg(1), p);
return ctx => CompileHelpers.ToBool(val1(ctx)) || CompileHelpers.ToBool(val2(ctx));
}
case Z3_decl_kind.Z3_OP_EQ:
{
var val1 = Compile(expr.Arg(0), p);
var val2 = Compile(expr.Arg(1), p);
return ctx => CompileHelpers.Equals(val1(ctx), val2(ctx));
}
case Z3_decl_kind.Z3_OP_FPA_EQ:
{
if (expr.NumArgs == 3)
{
var val1 = Compile(expr.Arg(1), p);
var val2 = Compile(expr.Arg(2), p);
return ctx => CompileHelpers.ToDouble(val1(ctx)) == CompileHelpers.ToDouble(val2(ctx));
} else
{
var val1 = Compile(expr.Arg(0), p);
var val2 = Compile(expr.Arg(1), p);
return ctx => CompileHelpers.ToDouble(val1(ctx)) == CompileHelpers.ToDouble(val2(ctx));
}
}
case Z3_decl_kind.Z3_OP_ITE:
{
var cond = Compile(expr.Arg(0), p);
var trueVal = Compile(expr.Arg(1), p);
var falseVal = Compile(expr.Arg(2), p);
return ctx =>
{
if (CompileHelpers.ToBool(cond(ctx)))
{
return trueVal(ctx);
} else
{
return falseVal(ctx);
}
};
}
case Z3_decl_kind.Z3_OP_FPA_GT:
{
if (expr.NumArgs == 3)
{
var val1 = Compile(expr.Arg(1), p);
var val2 = Compile(expr.Arg(2), p);
return ctx => CompileHelpers.ToDouble(val1(ctx)) > CompileHelpers.ToDouble(val2(ctx));
} else
{
var val1 = Compile(expr.Arg(0), p);
var val2 = Compile(expr.Arg(1), p);
return ctx => CompileHelpers.ToDouble(val1(ctx)) > CompileHelpers.ToDouble(val2(ctx));
}
}
case Z3_decl_kind.Z3_OP_FPA_GE:
{
var val1 = Compile(expr.Arg(expr.NumArgs == 3 ? 1u : 0u), p);
var val2 = Compile(expr.Arg(expr.NumArgs == 3 ? 2u : 1u), p);
return ctx => CompileHelpers.ToDouble(val1(ctx)) >= CompileHelpers.ToDouble(val2(ctx));
}
case Z3_decl_kind.Z3_OP_FPA_LT:
{
if (expr.NumArgs == 3)
{
var val1 = Compile(expr.Arg(1), p);
var val2 = Compile(expr.Arg(2), p);
return ctx => CompileHelpers.ToDouble(val1(ctx)) < CompileHelpers.ToDouble(val2(ctx));
} else
{
var val1 = Compile(expr.Arg(0), p);
var val2 = Compile(expr.Arg(1), p);
return ctx => CompileHelpers.ToDouble(val1(ctx)) < CompileHelpers.ToDouble(val2(ctx));
}
}
case Z3_decl_kind.Z3_OP_FPA_IS_NAN:
{
var val1 = Compile(expr.Arg(0), p);
return ctx => double.IsNaN(CompileHelpers.ToDouble(val1(ctx)));
}
case Z3_decl_kind.Z3_OP_BADD:
{
var val1 = Compile(expr.Arg(0), p);
var val2 = Compile(expr.Arg(1), p);
return ctx => CompileHelpers.ToUlong(val1(ctx)) + CompileHelpers.ToUlong(val2(ctx));
}
case Z3_decl_kind.Z3_OP_FPA_ADD:
{
var val1 = Compile(expr.Arg(1), p);
var val2 = Compile(expr.Arg(2), p);
return ctx => CompileHelpers.ToDouble(val1(ctx)) + CompileHelpers.ToDouble(val2(ctx));
}
case Z3_decl_kind.Z3_OP_BSUB:
{
var val1 = Compile(expr.Arg(0), p);
var val2 = Compile(expr.Arg(1), p);
return ctx => CompileHelpers.ToUlong(val1(ctx)) - CompileHelpers.ToUlong(val2(ctx));
}
case Z3_decl_kind.Z3_OP_FPA_SUB:
{
var val1 = Compile(expr.Arg(1), p);
var val2 = Compile(expr.Arg(2), p);
return ctx => CompileHelpers.ToDouble(val1(ctx)) - CompileHelpers.ToDouble(val2(ctx));
}
case Z3_decl_kind.Z3_OP_BMUL:
{
var val1 = Compile(expr.Arg(0), p);
var val2 = Compile(expr.Arg(1), p);
return ctx => CompileHelpers.ToUlong(val1(ctx)) * CompileHelpers.ToUlong(val2(ctx));
}
case Z3_decl_kind.Z3_OP_FPA_MUL:
{
var val1 = Compile(expr.Arg(1), p);
var val2 = Compile(expr.Arg(2), p);
return ctx => CompileHelpers.ToDouble(val1(ctx)) * CompileHelpers.ToDouble(val2(ctx));
}
case Z3_decl_kind.Z3_OP_BUREM:
case Z3_decl_kind.Z3_OP_BSREM:
{
var val1 = Compile(expr.Arg(0), p);
var val2 = Compile(expr.Arg(1), p);
return ctx => CompileHelpers.ToUlong(val1(ctx)) % CompileHelpers.ToUlong(val2(ctx));
}
case Z3_decl_kind.Z3_OP_FPA_REM:
{
var val1 = Compile(expr.Arg(expr.NumArgs == 3 ? 1u : 0u), p);
var val2 = Compile(expr.Arg(expr.NumArgs == 3 ? 2u : 1u), p);
return ctx => CompileHelpers.ToDouble(val1(ctx)) % CompileHelpers.ToDouble(val2(ctx));
}
case Z3_decl_kind.Z3_OP_BAND:
{
var val1 = Compile(expr.Arg(0), p);
var val2 = Compile(expr.Arg(1), p);
return ctx => CompileHelpers.ToUlong(val1(ctx)) & CompileHelpers.ToUlong(val2(ctx));
}
case Z3_decl_kind.Z3_OP_BOR:
{
var val1 = Compile(expr.Arg(0), p);
var val2 = Compile(expr.Arg(1), p);
return ctx => CompileHelpers.ToUlong(val1(ctx)) | CompileHelpers.ToUlong(val2(ctx));
}
case Z3_decl_kind.Z3_OP_BXOR:
{
var val1 = Compile(expr.Arg(0), p);
var val2 = Compile(expr.Arg(1), p);
return ctx => CompileHelpers.ToUlong(val1(ctx)) ^ CompileHelpers.ToUlong(val2(ctx));
}
case Z3_decl_kind.Z3_OP_BSHL:
{
var val1 = Compile(expr.Arg(0), p);
var val2 = Compile(expr.Arg(1), p);
return ctx => CompileHelpers.Shl(CompileHelpers.ToUlong(val1(ctx)), CompileHelpers.ToUlong(val2(ctx)));
}
case Z3_decl_kind.Z3_OP_BASHR:
{
var val1 = Compile(expr.Arg(0), p);
var val2 = Compile(expr.Arg(1), p);
return ctx => CompileHelpers.Shr(CompileHelpers.ToUlong(val1(ctx)), CompileHelpers.ToUlong(val2(ctx)));
}
case Z3_decl_kind.Z3_OP_ULT:
case Z3_decl_kind.Z3_OP_SLT:
{
var val1 = Compile(expr.Arg(0), p);
var val2 = Compile(expr.Arg(1), p);
return ctx => CompileHelpers.ToUlong(val1(ctx)) < CompileHelpers.ToUlong(val2(ctx));
}
case Z3_decl_kind.Z3_OP_LE:
case Z3_decl_kind.Z3_OP_ULEQ:
{
var val1 = Compile(expr.Arg(0), p);
var val2 = Compile(expr.Arg(1), p);
return ctx => CompileHelpers.ToUlong(val1(ctx)) <= CompileHelpers.ToUlong(val2(ctx));
}
case Z3_decl_kind.Z3_OP_UGT:
case Z3_decl_kind.Z3_OP_SGT:
{
var val1 = Compile(expr.Arg(0), p);
var val2 = Compile(expr.Arg(1), p);
return ctx => CompileHelpers.ToUlong(val1(ctx)) > CompileHelpers.ToUlong(val2(ctx));
}
case Z3_decl_kind.Z3_OP_GE:
case Z3_decl_kind.Z3_OP_UGEQ:
{
var val1 = Compile(expr.Arg(0), p);
var val2 = Compile(expr.Arg(1), p);
return ctx => CompileHelpers.ToUlong(val1(ctx)) >= CompileHelpers.ToUlong(val2(ctx));
}
case Z3_decl_kind.Z3_OP_BUDIV:
case Z3_decl_kind.Z3_OP_BSDIV:
{
var val1 = Compile(expr.Arg(0), p);
var val2 = Compile(expr.Arg(1), p);
return ctx => CompileHelpers.ToUlong(val1(ctx)) / CompileHelpers.ToUlong(val2(ctx));
}
case Z3_decl_kind.Z3_OP_FPA_DIV:
{
var val1 = Compile(expr.Arg(1), p);
var val2 = Compile(expr.Arg(2), p);
return ctx => CompileHelpers.ToDouble(val1(ctx)) / CompileHelpers.ToDouble(val2(ctx));
}
case Z3_decl_kind.Z3_OP_CONCAT:
{
// concat only used to extend a value with 0s, so ignore the first argument
var val = Compile(expr.Arg(1), p);
return ctx => CompileHelpers.ToUlong(val(ctx));
}
case Z3_decl_kind.Z3_OP_EXTRACT:
{
var val = Compile(expr.Arg(1), p);
return ctx => CompileHelpers.ToUlong(val(ctx));
}
case Z3_decl_kind.Z3_OP_FPA_TO_FP:
case Z3_decl_kind.Z3_OP_FPA_TO_FP_UNSIGNED:
{
return Compile(expr.Arg(1), p);
}
case Z3_decl_kind.Z3_OP_FPA_TO_SBV:
case Z3_decl_kind.Z3_OP_FPA_TO_UBV:
{
var val = Compile(expr.Arg(1), p);
return ctx => CompileHelpers.ToUlong(val(ctx));
}
case Z3_decl_kind.Z3_OP_BNUM:
{
var val = ulong.Parse(expr.ToString());
return ctx => val;
}
case Z3_decl_kind.Z3_OP_FPA_PLUS_INF:
{
var val = double.PositiveInfinity;
return ctx => val;
}
case Z3_decl_kind.Z3_OP_FPA_MINUS_INF:
{
var val = double.NegativeInfinity;
return ctx => val;
}
case Z3_decl_kind.Z3_OP_FPA_PLUS_ZERO:
{
var val = +0.0;
return ctx => val;
}
case Z3_decl_kind.Z3_OP_FPA_MINUS_ZERO:
{
var val = -0.0;
return ctx => val;
}
case Z3_decl_kind.Z3_OP_FPA_NUM:
{
var val = double.Parse(expr.ToString());
return ctx => val;
}
case Z3_decl_kind.Z3_OP_TRUE:
return ctx => true;
case Z3_decl_kind.Z3_OP_FALSE:
return ctx => false;
case Z3_decl_kind.Z3_OP_UNINTERPRETED:
{
var val = ResolveVariable(expr.FuncDecl.Name.ToString(), p);
return ctx =>
{
return val(ctx);
};
}
default:
throw new ResolutionException("unsupported expr: " + expr + " (kind " + expr.FuncDecl.DeclKind + ")");
}
}
}
}