/// <summary> Try/Catch/Finally
///
/// The IRFactory tries to express as much as possible in the tree;
/// the responsibilities remaining for Codegen are to add the Java
/// handlers: (Either (but not both) of TARGET and FINALLY might not
/// be defined)
/// - a catch handler for javascript exceptions that unwraps the
/// exception onto the stack and GOTOes to the catch target
/// - a finally handler
/// ... and a goto to GOTO around these handlers.
/// </summary>
internal Node CreateTryCatchFinally(Node tryBlock, Node catchBlocks, Node finallyBlock, int lineno)
{
bool hasFinally = (finallyBlock != null) && (finallyBlock.Type != Token.BLOCK || finallyBlock.hasChildren ());
// short circuit
if (tryBlock.Type == Token.BLOCK && !tryBlock.hasChildren () && !hasFinally) {
return tryBlock;
}
bool hasCatch = catchBlocks.hasChildren ();
// short circuit
if (!hasFinally && !hasCatch) {
// bc finally might be an empty block...
return tryBlock;
}
Node handlerBlock = new Node (Token.LOCAL_BLOCK);
Node.Jump pn = new Node.Jump (Token.TRY, tryBlock, lineno);
pn.putProp (Node.LOCAL_BLOCK_PROP, handlerBlock);
if (hasCatch) {
// jump around catch code
Node endCatch = Node.newTarget ();
pn.addChildToBack (makeJump (Token.GOTO, endCatch));
// make a TARGET for the catch that the tcf node knows about
Node catchTarget = Node.newTarget ();
pn.target = catchTarget;
// mark it
pn.addChildToBack (catchTarget);
//
// Given
//
// try {
// tryBlock;
// } catch (e if condition1) {
// something1;
// ...
//
// } catch (e if conditionN) {
// somethingN;
// } catch (e) {
// somethingDefault;
// }
//
// rewrite as
//
// try {
// tryBlock;
// goto after_catch:
// } catch (x) {
// with (newCatchScope(e, x)) {
// if (condition1) {
// something1;
// goto after_catch;
// }
// }
// ...
// with (newCatchScope(e, x)) {
// if (conditionN) {
// somethingN;
// goto after_catch;
// }
// }
// with (newCatchScope(e, x)) {
// somethingDefault;
// goto after_catch;
// }
// }
// after_catch:
//
// If there is no default catch, then the last with block
// arround "somethingDefault;" is replaced by "rethrow;"
// It is assumed that catch handler generation will store
// exeception object in handlerBlock register
// Block with local for exception scope objects
Node catchScopeBlock = new Node (Token.LOCAL_BLOCK);
// expects catchblocks children to be (cond block) pairs.
Node cb = catchBlocks.FirstChild;
bool hasDefault = false;
int scopeIndex = 0;
while (cb != null) {
int catchLineNo = cb.Lineno;
Node name = cb.FirstChild;
Node cond = name.Next;
Node catchStatement = cond.Next;
cb.removeChild (name);
cb.removeChild (cond);
cb.removeChild (catchStatement);
// Add goto to the catch statement to jump out of catch
// but prefix it with LEAVEWITH since try..catch produces
// "with"code in order to limit the scope of the exception
// object.
catchStatement.addChildToBack (new Node (Token.LEAVEWITH));
catchStatement.addChildToBack (makeJump (Token.GOTO, endCatch));
// Create condition "if" when present
Node condStmt;
if (cond.Type == Token.EMPTY) {
condStmt = catchStatement;
hasDefault = true;
}
else {
condStmt = CreateIf (cond, catchStatement, null, catchLineNo);
}
// Generate code to Create the scope object and store
// it in catchScopeBlock register
Node catchScope = new Node (Token.CATCH_SCOPE, name, CreateUseLocal (handlerBlock));
catchScope.putProp (Node.LOCAL_BLOCK_PROP, catchScopeBlock);
catchScope.putIntProp (Node.CATCH_SCOPE_PROP, scopeIndex);
catchScopeBlock.addChildToBack (catchScope);
// Add with statement based on catch scope object
catchScopeBlock.addChildToBack (CreateWith (CreateUseLocal (catchScopeBlock), condStmt, catchLineNo));
// move to next cb
cb = cb.Next;
++scopeIndex;
}
pn.addChildToBack (catchScopeBlock);
if (!hasDefault) {
// Generate code to rethrow if no catch clause was executed
Node rethrow = new Node (Token.RETHROW);
rethrow.putProp (Node.LOCAL_BLOCK_PROP, handlerBlock);
pn.addChildToBack (rethrow);
}
pn.addChildToBack (endCatch);
}
if (hasFinally) {
Node finallyTarget = Node.newTarget ();
pn.Finally = finallyTarget;
// add jsr finally to the try block
pn.addChildToBack (makeJump (Token.JSR, finallyTarget));
// jump around finally code
Node finallyEnd = Node.newTarget ();
pn.addChildToBack (makeJump (Token.GOTO, finallyEnd));
pn.addChildToBack (finallyTarget);
Node fBlock = new Node (Token.FINALLY, finallyBlock);
fBlock.putProp (Node.LOCAL_BLOCK_PROP, handlerBlock);
pn.addChildToBack (fBlock);
pn.addChildToBack (finallyEnd);
}
handlerBlock.addChildToBack (pn);
return handlerBlock;
}
internal Node CreatePropertyGet(Node target, string ns, string name, int memberTypeFlags)
{
if (ns == null && memberTypeFlags == 0) {
if (target == null) {
return CreateName (name);
}
checkActivationName (name, Token.GETPROP);
if (ScriptRuntime.isSpecialProperty (name)) {
Node rf = new Node (Token.REF_SPECIAL, target);
rf.putProp (Node.NAME_PROP, name);
return new Node (Token.GET_REF, rf);
}
return new Node (Token.GETPROP, target, CreateString (name));
}
Node elem = CreateString (name);
memberTypeFlags |= Node.PROPERTY_FLAG;
return CreateMemberRefGet (target, ns, elem, memberTypeFlags);
}
/// <summary> Object Literals
/// <BR> CreateObjectLiteral rewrites its argument as object
/// creation plus object property entries, so later compiler
/// stages don't need to know about object literals.
/// </summary>
internal Node CreateObjectLiteral(ObjArray elems)
{
int size = elems.size () / 2;
Node obj = new Node (Token.OBJECTLIT);
object [] properties;
if (size == 0) {
properties = ScriptRuntime.EmptyArgs;
}
else {
properties = new object [size];
for (int i = 0; i != size; ++i) {
properties [i] = elems.Get (2 * i);
Node value = (Node)elems.Get (2 * i + 1);
obj.addChildToBack (value);
}
}
obj.putProp (Node.OBJECT_IDS_PROP, properties);
return obj;
}
/// <summary> For .. In
///
/// </summary>
internal Node CreateForIn(Node loop, Node lhs, Node obj, Node body, bool isForEach)
{
int type = lhs.Type;
Node lvalue;
if (type == Token.VAR) {
/*
* check that there was only one variable given.
* we can't do this in the parser, because then the
* parser would have to know something about the
* 'init' node of the for-in loop.
*/
Node lastChild = lhs.LastChild;
if (lhs.FirstChild != lastChild) {
parser.ReportError ("msg.mult.index");
}
lvalue = Node.newString (Token.NAME, lastChild.String);
}
else {
lvalue = makeReference (lhs);
if (lvalue == null) {
parser.ReportError ("msg.bad.for.in.lhs");
return obj;
}
}
Node localBlock = new Node (Token.LOCAL_BLOCK);
int initType = (isForEach) ? Token.ENUM_INIT_VALUES : Token.ENUM_INIT_KEYS;
Node init = new Node (initType, obj);
init.putProp (Node.LOCAL_BLOCK_PROP, localBlock);
Node cond = new Node (Token.ENUM_NEXT);
cond.putProp (Node.LOCAL_BLOCK_PROP, localBlock);
Node id = new Node (Token.ENUM_ID);
id.putProp (Node.LOCAL_BLOCK_PROP, localBlock);
Node newBody = new Node (Token.BLOCK);
Node assign = simpleAssignment (lvalue, id);
newBody.addChildToBack (new Node (Token.EXPR_VOID, assign));
newBody.addChildToBack (body);
loop = CreateWhile (loop, cond, newBody);
loop.addChildToFront (init);
if (type == Token.VAR)
loop.addChildToFront (lhs);
localBlock.addChildToBack (loop);
return localBlock;
}
internal Node CreateArrayLiteral(ObjArray elems, int skipCount)
{
int length = elems.size ();
int [] skipIndexes = null;
if (skipCount != 0) {
skipIndexes = new int [skipCount];
}
Node array = new Node (Token.ARRAYLIT);
for (int i = 0, j = 0; i != length; ++i) {
Node elem = (Node)elems.Get (i);
if (elem != null) {
array.addChildToBack (elem);
}
else {
skipIndexes [j] = i;
++j;
}
}
if (skipCount != 0) {
array.putProp (Node.SKIP_INDEXES_PROP, skipIndexes);
}
return array;
}
internal Node CreateUseLocal(Node localBlock)
{
if (Token.LOCAL_BLOCK != localBlock.Type)
throw Context.CodeBug ();
Node result = new Node (Token.LOCAL_LOAD);
result.putProp (Node.LOCAL_BLOCK_PROP, localBlock);
return result;
}