Introduce scopes to keep track of catch blocks at compile time.

src/full-codegen.cc

Index: src/full-codegen.cc
diff --git a/src/full-codegen.cc b/src/full-codegen.cc
index 03abfbd85d59b358f1bb758070de41c484a55ea3..70db6114a288bcbb799ccb2d8c3941b265afc015 100644
--- a/src/full-codegen.cc
+++ b/src/full-codegen.cc
@@ -401,7 +401,7 @@ int FullCodeGenerator::SlotOffset(Slot* slot) {
   // Adjust by a (parameter or local) base offset.
   switch (slot->type()) {
     case Slot::PARAMETER:
-      offset += (scope()->num_parameters() + 1) * kPointerSize;
+      offset += (info_->scope()->num_parameters() + 1) * kPointerSize;

[Mads Ager (chromium), 2011/06/30 12:08:32]

Do you need this change? Don't you have a scope here already so you can just use
the scope() accessor?

[Kevin Millikin (Chromium), 2011/06/30 12:30:06]

This definitely needs to be the function's scope (info_->scope()), not the
current scope which might be a catch scope, where num_parameters() == 0.

[Mads Ager (chromium), 2011/06/30 12:47:44]

Should we create an accessor for that then: function_scope and scope?

       break;
     case Slot::LOCAL:
       offset += JavaScriptFrameConstants::kLocal0Offset;
@@ -1106,7 +1106,7 @@ void FullCodeGenerator::VisitTryCatchStatement(TryCatchStatement* stmt) {
 
   // Extend the context before executing the catch block.
   { Comment cmnt(masm_, "[ Extend catch context");
-    __ Push(stmt->name());
+    __ Push(stmt->variable()->name());
     __ push(result_register());
     PushFunctionArgumentForContextAllocation();
     __ CallRuntime(Runtime::kPushCatchContext, 3);
@@ -1114,7 +1114,11 @@ void FullCodeGenerator::VisitTryCatchStatement(TryCatchStatement* stmt) {
                       context_register());
   }
 
+  Scope* saved_scope = scope();

[Mads Ager (chromium), 2011/06/30 12:08:32]

Could use a comment? We could create a scope object for this if we need it in
more places (but it doesn't look like it is?)

[Kevin Millikin (Chromium), 2011/06/30 12:30:06]

It's only used here and I couldn't think of a comment that was more obvious than
the code itself.  Suggestions?

[Mads Ager (chromium), 2011/06/30 12:47:44]

Not sure anything is really needed. You are right that the code is pretty self
explanatory. I was thinking something like:

"Use the scope extended with the catch variable for compiling the catch block."

to match the "Extend" comment above which is nice, but doesn't say anything more
than the code either.

+  scope_ = stmt->scope();
+  ASSERT(scope_->declarations()->is_empty());
   Visit(stmt->catch_block());
+  scope_ = saved_scope;
   __ jmp(&done);
 
   // Try block code. Sets up the exception handler chain.