First round of size reduction for JumpTargets. Reduce their size by

two words: there is no reason to keep a pointer to the current code
generator and macro assembler in the JumpTarget.
Review URL: http://codereview.chromium.org/113458

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1987 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/codegen.cc

@@ -47,8 +47,7 @@ CodeGenerator* CodeGeneratorScope::top_ = NULL;
 DeferredCode::DeferredCode(CodeGenerator* generator)
   : generator_(generator),
     masm_(generator->masm()),
-    enter_(generator),
-    exit_(generator, JumpTarget::BIDIRECTIONAL),
+    exit_(JumpTarget::BIDIRECTIONAL),
     statement_position_(masm_->current_statement_position()),
     position_(masm_->current_position()) {
   generator->AddDeferred(this);

src/ia32/macro-assembler-ia32.cc

@@ -631,7 +631,7 @@ void MacroAssembler::NegativeZeroTest(CodeGenerator* cgen,
                                       Register result,
                                       Register op,
                                       JumpTarget* then_target) {
-  JumpTarget ok(cgen);
+  JumpTarget ok;
   test(result, Operand(result));
   ok.Branch(not_zero, taken);
   test(op, Operand(op));

src/jump-target-inl.h

@@ -30,6 +30,10 @@
 
 namespace v8 { namespace internal {
 
+CodeGenerator* JumpTarget::cgen() {
+  return CodeGeneratorScope::Current();
+}
+
 void JumpTarget::InitializeEntryElement(int index, FrameElement* target) {
   entry_frame_->elements_[index].clear_copied();
   if (target->is_register()) {

src/jump-target.h

@@ -56,31 +56,34 @@ class JumpTarget : public ZoneObject {  // Shadows are dynamically allocated.
   // Forward-only jump targets can only be reached by forward CFG edges.
   enum Directionality { FORWARD_ONLY, BIDIRECTIONAL };
 
-  // Construct a jump target with a given code generator used to generate
-  // code and to provide access to a current frame.
-  explicit JumpTarget(CodeGenerator* cgen,
-                      Directionality direction = FORWARD_ONLY);
+  // Construct a jump target used to generate code and to provide
+  // access to a current frame.
+  explicit JumpTarget(Directionality direction)
+      : direction_(direction),
+        reaching_frames_(0),
+        merge_labels_(0),
+        entry_frame_(NULL) {
+  }
 
-  // Construct a jump target without a code generator.  A code
-  // generator must be supplied before using the jump target as a
-  // label.  This is useful, eg, when break targets are embedded in
-  // AST nodes.
-  JumpTarget();
+  // Construct a jump target.
+  JumpTarget()
+      : direction_(FORWARD_ONLY),
+        reaching_frames_(0),
+        merge_labels_(0),
+        entry_frame_(NULL) {
+  }
 
   virtual ~JumpTarget() {}
 
-  // Supply a code generator and directionality to an already
-  // constructed jump target.  This function expects to be given a
-  // non-null code generator, and to be called only when the code
-  // generator is not yet set.
-  virtual void Initialize(CodeGenerator* cgen,
-                          Directionality direction = FORWARD_ONLY);
+  // Set the direction of the jump target.
+  virtual void set_direction(Directionality direction) {
+    direction_ = direction;
+  }
 
   // Treat the jump target as a fresh one.  The state is reset.
   void Unuse();
 
-  // Accessors.
-  CodeGenerator* code_generator() const { return cgen_; }
+  inline CodeGenerator* cgen();
 
   Label* entry_label() { return &entry_label_; }
 
@@ -163,12 +166,6 @@ class JumpTarget : public ZoneObject {  // Shadows are dynamically allocated.
   }
 
  protected:
-  // The code generator gives access to its current frame.
-  CodeGenerator* cgen_;
-
-  // Used to emit code.
-  MacroAssembler* masm_;
-
   // Directionality flag set at initialization time.
   Directionality direction_;
 
@@ -224,20 +221,13 @@ class JumpTarget : public ZoneObject {  // Shadows are dynamically allocated.
 
 class BreakTarget : public JumpTarget {
  public:
-  // Construct a break target without a code generator.  A code
-  // generator must be supplied before using the break target as a
-  // label.  This is useful, eg, when break targets are embedded in AST
-  // nodes.
+  // Construct a break target.
   BreakTarget() {}
 
   virtual ~BreakTarget() {}
 
-  // Supply a code generator, expected expression stack height, and
-  // directionality to an already constructed break target.  This
-  // function expects to be given a non-null code generator, and to be
-  // called only when the code generator is not yet set.
-  virtual void Initialize(CodeGenerator* cgen,
-                          Directionality direction = FORWARD_ONLY);
+  // Set the direction of the break target.
+  virtual void set_direction(Directionality direction);
 
   // Copy the state of this break target to the destination.  The
   // lists of forward-reaching frames and merge-point labels are