public override AstNode Visit(TryStatement node)
{
// Begin the node.
builder.BeginNode(node);
// Read the substatements.
AstNode tryNode = node.GetTryStatement();
AstNode catchList = node.GetCatchList();
AstNode finalNode = node.GetFinallyStatement();
// Read the exception context.
ExceptionContext context = node.GetContext();
// Create the finally block.
BasicBlock finalBlock = null;
if(finalNode != null)
{
finalBlock = CreateBasicBlock();
finalBlock.SetName("finally");
context.SetCleanup(finalBlock);
}
// Create the merge block.
BasicBlock merge = finalBlock;
if(merge == null)
{
merge = CreateBasicBlock();
merge.SetName("trymerge");
}
// Store the old context.
ExceptionContext oldContext = currentExceptionContext;
currentExceptionContext = context;
// Create the try block.
BasicBlock tryBlock = CreateBasicBlock();
tryBlock.SetName("try");
builder.CreateJmp(tryBlock);
builder.SetBlock(tryBlock);
// Process the try statement.
tryNode.Accept(this);
// Jump to finally/merge.
bool tryReturn = builder.IsLastTerminator();
if(!builder.IsLastTerminator())
builder.CreateJmp(merge);
// Restore the context, visit the catch list.
currentExceptionContext = oldContext;
AstNode catchNode = catchList;
while(catchNode != null)
{
// Visit it.
catchNode.Accept(this);
// Jump to finally/merge.
if(!builder.IsLastTerminator())
builder.CreateJmp(merge);
// TODO: Avoid "duplicated" catches.
catchNode = catchNode.GetNext();
}
// Visit the finally statement
if(finalNode != null)
{
// Generate the finally block.
builder.SetBlock(finalBlock);
// Visit it.
finalNode.Accept(this);
// Jump/resume to merge.
if(builder.IsLastTerminator())
Error(finalNode, "finally cannot return.");
// Create propagate return block.
BasicBlock propRet = CreateBasicBlock();
propRet.SetName("propRet");
builder.CreateJumpResume(propRet);
builder.SetBlock(propRet);
// Find the parent return.
BasicBlock parentRetBlock = null;
ExceptionContext parentContext = context.GetParentContext();
while(parentContext != null)
{
parentRetBlock = parentContext.GetCleanup();
if(parentRetBlock != null)
break;
parentContext = parentContext.GetParentContext();
}
// Couldn't find a parent cleanup, return.
if(parentRetBlock == null)
parentRetBlock = currentFunction.ReturnBlock;
// If try returns and theres not catch, just return.
if(tryReturn && catchNode == null)
{
builder.CreateJmp(parentRetBlock);
AstNode next = node.GetNext();
if(next != null)
Warning(next, "unreachable code detected.");
node.SetNext(null);
}
else
{
// Merge with the other blocks.
merge = CreateBasicBlock();
merge.SetName("trymerge");
// Return/finally or merge.
builder.CreateLoadLocal(currentFunction.ReturningVar);
builder.CreateBr(parentRetBlock, merge);
}
}
// Remove unused code.
if(merge.GetPredsCount() == 0)
{
if(node.GetNext() != null)
Warning(node, "detected unreachable code at {0}", node.GetNext().GetPosition());
node.SetNext(null);
merge.Destroy();
}
else
{
// Continue without try.
builder.SetBlock(merge);
}
return builder.EndNode();
}
public override AstNode Visit(TryStatement node)
{
// Visit the try clause.
AstNode tryStatement = node.GetTryStatement();
tryStatement.Accept(this);
// Visit the catch clause.
VisitList(node.GetCatchList());
// Visit the finally clause.
AstNode finallyStament = node.GetFinallyStatement();
if(finallyStament != null)
finallyStament.Accept(this);
return node;
}
public override AstNode Visit(TryStatement node)
{
// Read the substatements.
AstNode tryNode = node.GetTryStatement();
AstNode catchList = node.GetCatchList();
AstNode finalNode = node.GetFinallyStatement();
// Create the exception context.
ExceptionContext context;
if(currentExceptionContext != null)
context = new ExceptionContext(currentExceptionContext);
else
context = new ExceptionContext(currentFunction);
node.SetContext(context);
// Store the old context and process the try statement.
ExceptionContext oldContext = currentExceptionContext;
currentExceptionContext = context;
tryNode.Accept(this);
// Restore the context, visit the catch list.
currentExceptionContext = oldContext;
AstNode catchNode = catchList;
while(catchNode != null)
{
// Set the exception context.
CatchStatement catchStmnt = (CatchStatement)catchNode;
catchStmnt.SetContext(context);
// Visit it.
catchStmnt.Accept(this);
// TODO: Avoid "duplicated" catches.
catchNode = catchNode.GetNext();
}
// Visit the finally statement
if(finalNode != null)
{
// Set the exception context.
FinallyStatement finalStmnt = (FinallyStatement)finalNode;
finalStmnt.SetContext(context);
// Visit it.
finalStmnt.Accept(this);
}
return node;
}
