public override Statement VisitBranch(Branch branch)
{
if(branch == null)
return null;
if(branch.Target == null)
return null;
branch.Condition = this.VisitExpression(branch.Condition);
int n = this.localsStack.top + 1;
LocalsStack targetStack = (LocalsStack)this.StackLocalsAtEntry[branch.Target.UniqueKey];
if(targetStack == null)
{
this.StackLocalsAtEntry[branch.Target.UniqueKey] = this.localsStack.Clone();
return branch;
}
// Target block has an entry stack that is different from the current stack. Need to copy stack
// before branching.
if(n <= 0)
return branch; //Empty stack, no need to copy
StatementList statements = new StatementList();
this.localsStack.Transfer(targetStack, statements);
statements.Add(branch);
return new Block(statements);
}
public override void VisitBranch(Branch branch)
{
if (branch == null || branch.Target == null) return;
if (branch.Target == branchTargetToReplace)
{
branch.Target = this.newBranchTarget;
return;
}
base.VisitBranch(branch);
}
//public override Block VisitBlock(Block block) {
// if(block.Statements != null && block.Statements.Count == 1) {
// Return r = block.Statements[0] as Return;
// if(r != null) {
// Statement s = this.VisitReturn(r);
// Block retBlock = s as Block;
// if(retBlock != null) {
// block.Statements = retBlock.Statements;
// return block;
// } else {
// return base.VisitBlock(block);
// }
// } else {
// return base.VisitBlock(block);
// }
// } else {
// return base.VisitBlock(block);
// }
//}
public override Statement VisitReturn(Return Return)
{
if (Return == null)
{
return null;
}
returnCount++;
this.lastReturnSourceContext = Return.SourceContext;
StatementList stmts = new StatementList();
Return.Expression = this.VisitExpression(Return.Expression);
if (Return.Expression != null)
{
MethodCall mc = Return.Expression as MethodCall;
if (mc != null && mc.IsTailCall)
{
mc.IsTailCall = false;
}
var assgnmt = new AssignmentStatement(result, Return.Expression);
assgnmt.SourceContext = Return.SourceContext;
stmts.Add(assgnmt);
}
// the branch is a "leave" out of the try block that the body will be
// in.
var branch = new Branch(null, newExit, false, false, this.leaveExceptionBody);
branch.SourceContext = Return.SourceContext;
stmts.Add(branch);
return new Block(stmts);
}
private static Statement WrapTryCatch(Method method, Statement statement)
{
Block afterCatches = new Block(new StatementList());
Block tryBlock = new Block(new StatementList());
Block blockAfterTryBody = new Block(null);
tryBlock.Statements.Add(statement);
tryBlock.Statements.Add(new Branch(null, afterCatches, false, true, true));
tryBlock.Statements.Add(blockAfterTryBody);
Block catchBlock = new Block(new StatementList());
// emit code that pops the exception and fools fxcop
Block branchTargetToFoolFxCop = new Block(null);
var branch = new Branch(new Expression(NodeType.Pop), branchTargetToFoolFxCop);
SourceContext hiddenContext = new SourceContext(HiddenDocument.Document);
branch.SourceContext = hiddenContext;
catchBlock.Statements.Add(branch);
var rethrowStatement = new Throw();
rethrowStatement.SourceContext = hiddenContext;
rethrowStatement.NodeType = NodeType.Rethrow;
catchBlock.Statements.Add(rethrowStatement);
catchBlock.Statements.Add(branchTargetToFoolFxCop);
var leave = new Branch(null, afterCatches, false, true, true);
leave.SourceContext = hiddenContext;
catchBlock.Statements.Add(leave);
Block tryCatch = new Block(new StatementList());
tryCatch.Statements.Add(tryBlock);
tryCatch.Statements.Add(catchBlock);
tryCatch.Statements.Add(afterCatches);
if (method.ExceptionHandlers == null) method.ExceptionHandlers = new ExceptionHandlerList();
ExceptionHandler exHandler = new ExceptionHandler();
exHandler.TryStartBlock = tryBlock;
exHandler.BlockAfterTryEnd = blockAfterTryBody;
exHandler.HandlerStartBlock = catchBlock;
exHandler.BlockAfterHandlerEnd = afterCatches;
exHandler.FilterType = SystemTypes.Exception;
exHandler.HandlerType = NodeType.Catch;
method.ExceptionHandlers.Add(exHandler);
return tryCatch;
}
private void EmitRecursionGuardAroundChecks(Method method, Block newBody, StatementList checks)
{
StatementList stmts = new StatementList();
Block preconditionsStart = new Block(stmts);
Block finallyStart = null;
Block finallyEnd = new Block(); // branch target for skipping the checks
// test if we are an auto property and need to disable the check if we are in construction
if (this.ReentrancyFlag != null && (method.IsPropertyGetter || method.IsPropertySetter) && HelperMethods.IsAutoPropertyMember(method) && !method.IsStatic) {
newBody.Statements.Add(new Branch(new MemberBinding(method.ThisParameter, this.ReentrancyFlag), finallyEnd));
}
// don't add try finally if there are no precondition or if the method is a constructor (peverify issue)
if (NeedsRecursionGuard(method, checks))
{
// emit recursion check
finallyStart = new Block(new StatementList());
// if (insideContractEvaluation > $recursionGuard$) goto finallyEnd
// try {
// insideContractEvaluation++;
// checks;
// leave;
// } finally {
// insideContractEvaluation--;
// }
//
// SPECIAL CASE for auto properties where we made invariants into pre/post, we need to avoid the check if we are
// evaluating the invariant.
//
// if (this.$evaluatingInvariant || insideContractEvaluation > $recursionGuard$) goto finallyEnd
//
newBody.Statements.Add(new Branch(new BinaryExpression(new MemberBinding(null, this.runtimeContracts.InContractEvaluationField), new Literal(this.runtimeContracts.RecursionGuardCountFor(method), SystemTypes.Int32), NodeType.Gt), finallyEnd));
stmts.Add(new AssignmentStatement(new MemberBinding(null, this.runtimeContracts.InContractEvaluationField),
new BinaryExpression(new MemberBinding(null, this.runtimeContracts.InContractEvaluationField), Literal.Int32One, NodeType.Add)));
stmts.Add(new Block(checks));
var leave = new Branch();
leave.Target = finallyEnd;
leave.LeavesExceptionBlock = true;
stmts.Add(leave);
finallyStart.Statements.Add(new AssignmentStatement(new MemberBinding(null, this.runtimeContracts.InContractEvaluationField),
new BinaryExpression(new MemberBinding(null, this.runtimeContracts.InContractEvaluationField), Literal.Int32One, NodeType.Sub)));
finallyStart.Statements.Add(new EndFinally());
}
else
{
stmts.Add(new Block(checks));
}
newBody.Statements.Add(preconditionsStart);
if (finallyStart != null)
{
newBody.Statements.Add(finallyStart);
var finallyHandler = new ExceptionHandler();
finallyHandler.TryStartBlock = preconditionsStart;
finallyHandler.BlockAfterTryEnd = finallyStart;
finallyHandler.HandlerStartBlock = finallyStart;
finallyHandler.BlockAfterHandlerEnd = finallyEnd;
finallyHandler.HandlerType = NodeType.Finally;
method.ExceptionHandlers.Add(finallyHandler);
}
// branch target for skipping the checks
newBody.Statements.Add(finallyEnd);
}
public override void VisitBranch(Branch branch) {
branch.ShortOffset = false;
}
public override Statement VisitBranch(Branch branch)
{
if (branch == null) return null;
branch = (Branch)base.VisitBranch((Branch)branch.Clone());
if (branch == null) return null;
branch.Target = this.VisitBlock(branch.Target);
return branch;
}
public override Statement VisitBranch(Branch branch)
{
throw new NotImplementedException("Node type not yet supported");
}
public override Statement VisitBranch(Branch branch)
{
branch = (Branch)branch.Clone();
// remember this statement on the list to adjust branches
this.branchInstructions.Add(branch);
if (branch.Condition == null) return branch;
if (this.performConstantFoldingOnBranchConditions) {
Literal l = AsConstant(branch.Condition);
if (l != null) {
if (Equals(l.Value, true) || Equals(l.Value, 1)) {
branch.Condition = null;
return branch;
}
if (Equals(l.Value, false) || Equals(l.Value, 0)) {
return null;
}
}
}
branch.Condition = simplify(branch.Condition);
return branch;
}
public SpecialBranch (Branch oldBranch, Block target) : base(null, target) {
this.LeavesExceptionBlock = oldBranch.LeavesExceptionBlock;
this.SourceContext = oldBranch.SourceContext;
}
// The "leave" instruction block.Statements[i] is replaced with a branch instruction
// to a ChainBlocks of duplicated finally blocks (which are now normal blocks) that finally
// arrives in the original branch target.
private void ProcessLeave (Block block, int i, Branch leave) {
Debug.Assert(block != null);
Debug.Assert(block.Statements[i] is Branch && ((Branch)block.Statements[i]).LeavesExceptionBlock);
//Console.Out.WriteLine("process leave from " + CodePrinter.b2s(block) + "," + i);
Block originalLeaveTarget = ((Branch) block.Statements[i]).Target;
// 1. find the list of all finally blocks "traversed" by the branch
IEnumerable/*<ExceptionHandler>*/ list_finally = GetFinallyHandlersForLeave(block, i);
// 2. duplicate and ChainBlocks them with jumps between them
Block modBlock = block;
int modIndex = i; // the modIndex'th instruction of modBlock will be replaced with a "chaining" Branch
bool isFirstHandler = true;
Block firstBlockInFinally, lastBlockInFinally;
foreach(ExceptionHandler eh in list_finally) {
DuplicateFinallyBody(eh, block, out firstBlockInFinally, out lastBlockInFinally);
Debug.Assert(firstBlockInFinally != null && lastBlockInFinally != null);
ChainBlocks(modBlock, modIndex, firstBlockInFinally, isFirstHandler);
isFirstHandler = false;
modBlock = lastBlockInFinally;
}
ChainBlocks(modBlock, modIndex, originalLeaveTarget, isFirstHandler);
#if DEBUGxxx
Console.WriteLine();
Console.WriteLine("-------------------------------------------------------------");
Console.WriteLine();
SimpleDisplay(Console.Out, this.method);
Console.WriteLine("NEW:");
foreach (Block b in new_blocks)
{
SimpleDisplay(Console.Out, b, null);
}
#endif
}
public override Statement VisitBranch(Branch branch) {
if (branch == null) return null;
return ((Branch)branch.Clone());
}
public override Statement VisitBranch(Branch branch) {
// update the branch target for non-leave branches
if ( ! branch.LeavesExceptionBlock || branch is SpecialBranch) {
branch.Target = get_new_target(branch.Target);
}
return branch;
}
public override Statement VisitBranch(Branch branch)
{
if (branch == null) return null;
if (branch.Condition != null)
throw new InvalidOperationException("Unexpected branch condition in BBSplitter");
// Check to see if a basic block has been created for this target yet
BasicBlock bbTarget = (BasicBlock)branchTargets[branch.Target.UniqueKey];
// If not, create one now and register it in branchTargets
if (bbTarget == null)
{
bbTarget = new BasicBlock(null);
AddBlock(bbTarget);
bbTarget.SourceContext = branch.SourceContext;
bbTarget.MiddleOfTransition = true;
branchTargets[branch.Target.UniqueKey] = bbTarget;
}
#if false
// Note: this optimization was overly aggressive because it assumes that branch targets
// fall within the current atomic block. If not, then we need an extra "branch" block
// which can be the end of the atomic block.
if (this.insideAtomicBlock)
{
// We don't need a basic block for the branch itself. We just redirect the
// CurrentContinuation to the target of the branch.
CurrentContinuation = bbTarget;
}
else
#endif
{
// If we aren't in an atomic block, we can't optimize away the block for the
// goto itself.
BasicBlock branchBlock = new BasicBlock(null, bbTarget);
AddBlock(branchBlock);
branchBlock.SourceContext = branch.SourceContext;
CurrentContinuation = branchBlock;
// Remember this branch if it happens to be inside an atomic block. If the
// target is *not* within the atomic block, then we'll need to do some
// fixup work later.
if (this.insideAtomicBlock)
atomicBranches.Add(branchBlock);
}
return branch;
}
public virtual Statement VisitBranch(Branch branch)
{
if (branch == null) return null;
branch.Condition = this.VisitExpression(branch.Condition);
return branch;
}
public override Statement VisitBranch(Branch branch)
{
if (branch == null) return null;
if (branch.Target == null) return null;
this.VisitBlock(branch.Target);
this.lastBranchWasUnconditional = branch.Condition == null;
return branch;
}
public override Statement VisitBranch(Branch branch)
{
Debug.Assert(false, "Unexpected Branch node in Normalizer");
return null;
}
public EventingVisitor(Action<Branch> visitBranch) { VisitedBranch += visitBranch; } public event Action<Branch> VisitedBranch; public override Statement VisitBranch(Branch branch) { if (VisitedBranch != null) VisitedBranch(branch); return base.VisitBranch(branch); }
