private StackOfLocals(StackOfLocals template)
{
if (template.elements != null)
{
this.elements = (TempVariable[])template.elements.Clone();
}
this.top = template.top;
this.body = template.body;
}
private IStatement TransferStack(IStatement statement, StackOfLocals targetStack)
{
BasicBlock block = new BasicBlock(0);
this.operandStack.TransferTo(targetStack, block.Statements);
block.Statements.Add(statement);
this.operandStack = targetStack.Clone(this.block);
return(block);
}
internal void Visit(BasicBlock block)
{
this.block = block;
this.operandStack = new StackOfLocals(this.body);
this.codePointsToAnalyze.Enqueue(new CodePoint()
{
statements = block.Statements, index = 0, operandStack = this.operandStack
});
while (this.codePointsToAnalyze.Count > 0)
{
CodePoint codePoint = this.codePointsToAnalyze.Dequeue();
if (codePoint.operandStack == null)
{
//Can only get here for a code point with a label and labels are only created if there a branches to them.
//Sooner or later the branch must be encountered and then this code point will get an operand stack from the branch.
if (this.codePointsToAnalyze.Count == 0)
{
//But if we get here, there are NO other code blocks, so we'll loop forever if we just put codePoint back on the queue with an empty stack.
//Start with an empty stack and just carry on.
codePoint.operandStack = new StackOfLocals(this.body);
}
else
{
this.codePointsToAnalyze.Enqueue(codePoint); //keep looking for the branch.
continue;
}
}
this.operandStack = codePoint.operandStack.Clone(this.block);
List <IStatement> statements = codePoint.statements;
for (int i = codePoint.index; i < statements.Count; i++)
{
statements[i] = this.Visit(statements[i]);
if (this.visitedUnconditionalBranch)
{
this.visitedUnconditionalBranch = false;
if (i + 1 < statements.Count)
{
ILabeledStatement /*?*/ label = statements[i + 1] as ILabeledStatement;
if (label == null)
{
continue; //Unreachable code. Need to carry on though, since it may contain the only branch to a label.
}
this.codePointsToAnalyze.Enqueue(new CodePoint()
{
statements = statements, index = i + 1
});
}
break;
}
}
}
}
/// <summary>
/// Visits the specified block statement.
/// </summary>
/// <param name="blockStatement">The block statement.</param>
/// <returns></returns>
public override IBlockStatement Visit(BlockStatement blockStatement)
{
var savedBlock = this.block;
BasicBlock /*?*/ b = blockStatement as BasicBlock;
for (; ;)
{
if (b != null)
{
this.block = b;
int statementCount = b.Statements.Count;
BasicBlock /*?*/ bnext = null;
if (statementCount > 1 && b.Statements[statementCount - 2] is IGotoStatement)
{
bnext = b.Statements[--statementCount] as BasicBlock;
if (bnext != null)
{
b.Statements.RemoveAt(statementCount);
}
}
b.Statements = this.Visit(b.Statements);
if (bnext == null || bnext.Statements.Count == 0)
{
break;
}
ILabeledStatement labeledStatement = bnext.Statements[0] as ILabeledStatement;
if (labeledStatement != null)
{
StackOfLocals newStack = null;
if (this.stackFor.TryGetValue(labeledStatement, out newStack))
{
this.operandStack.TransferTo(newStack, b.Statements);
this.operandStack = newStack;
this.stackFor.Remove(labeledStatement);
}
}
b.Statements.Add(bnext);
b = bnext;
}
else
{
blockStatement.Statements = Visit(blockStatement.Statements);
break;
}
}
this.block = savedBlock;
return(blockStatement);
}
public override List <IStatement> Visit(List <IStatement> statements)
{
List <IStatement> newList = new List <IStatement>();
foreach (var statement in statements)
{
BasicBlock bb = statement as BasicBlock;
if (bb != null && bb.Statements.Count > 0)
{
ILabeledStatement labeledStatement = bb.Statements[0] as ILabeledStatement;
if (labeledStatement != null)
{
StackOfLocals newStack = null;
if (this.stackFor.TryGetValue(labeledStatement, out newStack))
{
this.operandStack.TransferTo(newStack, newList);
this.operandStack = newStack;
this.stackFor.Remove(labeledStatement);
}
}
}
IStatement newStatement;
newStatement = this.Visit(statement);
if (newStatement is IBlockStatement && !(statement is IBlockStatement))
{
newList.AddRange(((IBlockStatement)newStatement).Statements);
}
else
{
newList.Add(newStatement);
}
}
return(newList);
}
internal void TransferTo(StackOfLocals targetStack, List <IStatement> list)
{
Contract.Requires(targetStack != null);
Contract.Requires(list != null);
Contract.Requires(Contract.ForAll(list, x => x != null));
for (int i = 0; i <= this.top && i <= targetStack.top; i++)
{
Contract.Assert(this.top >= 0);
Contract.Assert(this.top < this.elements.Length);
var sourceLocal = this.elements[i];
Contract.Assert(targetStack.top >= 0);
Contract.Assume(targetStack.elements != null);
Contract.Assume(targetStack.top < targetStack.elements.Length);
var targetLocal = targetStack.elements[i];
Contract.Assume(targetLocal != null);
if (sourceLocal == targetLocal)
{
continue;
}
if (targetLocal.turnIntoPopValueExpression)
{
sourceLocal.turnIntoPopValueExpression = true;
}
else if (sourceLocal.turnIntoPopValueExpression)
{
targetLocal.turnIntoPopValueExpression = true;
}
else
{
Contract.Assume(this.body.numberOfReferences != null);
this.body.numberOfReferences[sourceLocal]++;
Contract.Assume(this.body.numberOfAssignments != null);
this.body.numberOfAssignments[targetLocal]++;
var targetType = targetLocal.Type;
var sourceType = sourceLocal.Type;
var mergedType = TypeHelper.MergedType(TypeHelper.StackType(targetType), TypeHelper.StackType(sourceType));
if (targetType != mergedType && !(targetType.TypeCode == PrimitiveTypeCode.Boolean && mergedType.TypeCode == PrimitiveTypeCode.Int32))
{
targetLocal.Type = mergedType;
targetType = mergedType;
if (targetType is Dummy || sourceType is Dummy)
{
targetLocal.isPolymorphic = true;
}
}
var target = new TargetExpression()
{
Definition = targetLocal, Type = targetType
};
var source = new BoundExpression()
{
Definition = sourceLocal, Type = sourceType
};
var assigment = new Assignment()
{
Target = target, Source = source, Type = targetType
};
list.Add(new ExpressionStatement()
{
Expression = assigment
});
}
}
//Contract.Assume(this.top < 0 || Contract.ForAll(0, this.top+1, i => this.elements[i] != null));
}
public override IStatement Visit(IStatement statement)
{
IGotoStatement gotoStatement = statement as IGotoStatement;
if (gotoStatement != null)
{
this.visitedUnconditionalBranch = true;
foreach (object ob in this.path)
{
if (ob is IConditionalStatement)
{
this.visitedUnconditionalBranch = false;
}
}
StackOfLocals newStack = null;
if (this.stackFor.TryGetValue(gotoStatement.TargetStatement, out newStack))
{
return(this.TransferStack(gotoStatement, newStack));
}
this.stackFor.Add(gotoStatement.TargetStatement, this.operandStack.Clone(this.block));
return(gotoStatement);
}
ILabeledStatement labeledStatement = statement as ILabeledStatement;
if (labeledStatement != null)
{
StackOfLocals newStack = null;
if (this.stackFor.TryGetValue(labeledStatement, out newStack))
{
return(this.TransferStack(labeledStatement, newStack));
}
this.stackFor.Add(labeledStatement, this.operandStack.Clone(this.block));
return(labeledStatement);
}
PushStatement /*?*/ push = statement as PushStatement;
if (push != null)
{
push.ValueToPush = this.Visit(push.ValueToPush);
this.tempCounter = this.body.localVariablesAndTemporaries.Count;
var temp = new TempVariable()
{
Name = this.body.host.NameTable.GetNameFor("__temp_" + this.tempCounter++)
};
temp.Type = push.ValueToPush.Type;
this.operandStack.Push(temp);
this.body.numberOfReferences.Add(temp, 0);
var ctc = push.ValueToPush as ICompileTimeConstant;
// "push null" doesn't tell us enough to know what type it really is
if (ctc != null && ctc.Value == null) // REVIEW: need to make sure the type is a reference type?
{
temp.isPolymorphic = true;
}
var be = push.ValueToPush as IBoundExpression;
if (be != null)
{
var sourceLocal = be.Definition as TempVariable;
if (sourceLocal != null && sourceLocal.isPolymorphic)
{
temp.isPolymorphic = true;
}
}
if (push.ValueToPush.Type is IManagedPointerTypeReference)
{
temp.turnIntoPopValueExpression = true;
return(statement);
}
this.body.localVariablesAndTemporaries.Add(temp);
if (this.block.LocalVariables == null)
{
this.block.LocalVariables = new List <ILocalDefinition>();
}
this.block.LocalVariables.Add(temp);
this.body.numberOfAssignments.Add(temp, 1);
return(new ExpressionStatement()
{
Expression = new Assignment()
{
Target = new TargetExpression()
{
Definition = temp
}, Source = push.ValueToPush
},
Locations = push.Locations
});
}
if (statement is EndFilter || statement is EndFinally)
{
this.visitedUnconditionalBranch = true;
return(statement);
}
if (statement is SwitchInstruction)
{
return(statement);
}
return(base.Visit(statement));
}
