internal ISatExpressionWrapper GetSolverExpressionFor(Instruction expression, List <List <Instruction> > listOfConjunctions = null)
{
Contract.Requires(expression != null);
Contract.Ensures(Contract.Result <ISatExpressionWrapper>() != null);
var wrapper = this.expressionMap[expression] as ISatExpressionWrapper;
if (wrapper == null)
{
if (!this.mappings.IsRecursive(expression))
{
expression = Simplifier.HoistPhiNodes(expression);
}
if (listOfConjunctions != null && expression.Type.TypeCode == PrimitiveTypeCode.Boolean && expression.Operation.OperationCode == OperationCode.Nop && expression.Operation.Value is INamedEntity)
{
wrapper = this.GetSolverExpressionForBooleanPhiNode(expression, listOfConjunctions);
}
else
{
var operand1 = expression.Operand1 as Instruction;
if (operand1 == null)
{
wrapper = this.satSolver.MakeExpression(expression.Operation, expression.Type);
}
else
{
var operand1wrapper = this.GetSolverExpressionFor(operand1, listOfConjunctions);
var operand2 = expression.Operand2 as Instruction;
if (operand2 == null)
{
wrapper = this.satSolver.MakeExpression(expression.Operation, expression.Type, operand1wrapper);
}
else
{
var operand2wrapper = this.GetSolverExpressionFor(operand2, listOfConjunctions);
wrapper = this.satSolver.MakeExpression(expression.Operation, expression.Type, operand1wrapper, operand2wrapper);
}
}
}
if (wrapper == null)
{
wrapper = this.satSolver.Dummy;
}
Contract.Assume(wrapper != null);
this.expressionMap[expression] = wrapper;
}
return(wrapper);
}
internal Instruction GetCanonicalExpression(Instruction naryInstruction, Instruction operand1, Instruction /*?*/ operand2, Instruction[] /*?*/ operands2andBeyond)
{
Contract.Requires(naryInstruction != null);
Contract.Requires(operand1 != null);
var expression = this.dummyInstruction;
expression.Operation = naryInstruction.Operation;
expression.Operand1 = this.GetCanonicalExpression(Simplifier.Simplify(operand1, this.mappings, this));
if (operand2 != null)
{
expression.Operand2 = this.GetCanonicalExpression(Simplifier.Simplify(operand2, this.mappings, this));
}
else if (operands2andBeyond != null)
{
var n = operands2andBeyond.Length;
var canonOps = new Instruction[n];
for (int i = 0; i < n; i++)
{
Contract.Assume(operands2andBeyond[i] != null);
canonOps[i] = this.GetCanonicalExpression(Simplifier.Simplify(operands2andBeyond[i], this.mappings, this));
}
expression.Operand2 = canonOps;
}
expression.Type = naryInstruction.Type;
Instruction result;
if (!this.cache.TryGetValue(expression, out result))
{
this.cache[expression] = result = expression;
this.dummyInstruction = new Instruction();
}
Contract.Assume(result != null);
return(result);
}
/// <summary>
/// If the cache contains an expression with an Operation structurally equivalent to unaryInstruction.Operation and Operand1 structurally equivalent to
/// operand1, then return that expression. Otherwise construct such an expression, add it to the cache and return it.
/// </summary>
/// <param name="unaryInstruction">An instruction with a single operand.</param>
/// <param name="operand1">The already canonicalized version of unaryInstruction.Operand1, if available, otherwise unaryInstruction.Operand1.</param>
internal Instruction GetCanonicalExpression(Instruction unaryInstruction, Instruction operand1)
{
Contract.Requires(unaryInstruction != null);
Contract.Requires(operand1 != null);
Contract.Ensures(Contract.Result <Instruction>() != null);
var expression = this.dummyInstruction;
expression.Operation = unaryInstruction.Operation;
expression.Operand1 = operand1;
expression.Operand2 = null;
expression.Type = unaryInstruction.Type;
Instruction result;
if (!this.cache.TryGetValue(expression, out result))
{
result = this.GetCanonicalExpression(Simplifier.SimplifyUnary(expression, this.mappings, this));
this.cache[expression] = result;
this.dummyInstruction = new Instruction();
}
Contract.Assume(result != null);
return(result);
}