Partial ia32 implementation of optimized try/catch (by Kevin Millikin)

src/hydrogen.h

Index: src/hydrogen.h
diff --git a/src/hydrogen.h b/src/hydrogen.h
index 7d23ac7306cce97bc31f21a29a2fdee8bceb7c14..7d8d261e379c532c1c699840287f2338c9685056 100644
--- a/src/hydrogen.h
+++ b/src/hydrogen.h
@@ -526,6 +526,13 @@ class HEnvironment: public ZoneObject {
 
   void SetExpressionStackAt(int index_from_top, HValue* value);
 
+  int handler_count() { return handler_count_; }
+  void AddExceptionHandler() { ++handler_count_; }
+  void RemoveExceptionHandler() {
+    ASSERT(handler_count_ > 0);
+    --handler_count_;
+  }
+
   HEnvironment* Copy() const;
   HEnvironment* CopyWithoutHistory() const;
   HEnvironment* CopyAsLoopHeader(HBasicBlock* block) const;
@@ -599,6 +606,7 @@ class HEnvironment: public ZoneObject {
   int parameter_count_;
   int specials_count_;
   int local_count_;
+  int handler_count_;
   HEnvironment* outer_;
   int pop_count_;
   int push_count_;
@@ -809,15 +817,15 @@ class HGraphBuilder: public AstVisitor {
   // can have a separate lifetime.
   class BreakAndContinueInfo BASE_EMBEDDED {
    public:
-    explicit BreakAndContinueInfo(BreakableStatement* target,
-                                  int drop_extra = 0)
-        : target_(target),
+    BreakAndContinueInfo(Statement* statement, int drop_extra)
+        : statement_(statement),
           break_block_(NULL),
           continue_block_(NULL),
           drop_extra_(drop_extra) {
     }
 
-    BreakableStatement* target() { return target_; }
+    Statement* statement() { return statement_; }
+
     HBasicBlock* break_block() { return break_block_; }
     void set_break_block(HBasicBlock* block) { break_block_ = block; }
     HBasicBlock* continue_block() { return continue_block_; }
@@ -825,7 +833,7 @@ class HGraphBuilder: public AstVisitor {
     int drop_extra() { return drop_extra_; }
 
    private:
-    BreakableStatement* target_;
+    Statement* statement_;
     HBasicBlock* break_block_;
     HBasicBlock* continue_block_;
     int drop_extra_;
@@ -846,8 +854,13 @@ class HGraphBuilder: public AstVisitor {
     HGraphBuilder* owner() { return owner_; }
     BreakAndContinueScope* next() { return next_; }
 
-    // Search the break stack for a break or continue target.
-    HBasicBlock* Get(BreakableStatement* stmt, BreakType type, int* drop_extra);
+    // Search the break stack for a break or continue target, emit any
+    // instructions necessary to unwind the break stack and emit a jump to
+    // the target block.
+    void Unwind(BreakableStatement* target, BreakType type);
+
+    // Unwind the entire break stack for returning from the function.
+    void UnwindReturn();
 
    private:
     BreakAndContinueInfo* info_;