Cache isolate in the StackTrace object to that we don't call

Isolate::Current in the destructor, HandleScope and Zone.
TBR=iposva (already reviewed change on other client).
Review URL: http://codereview.chromium.org//8523013

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@1427 260f80e4-7a28-3924-810f-c04153c831b5

runtime/vm/allocation.cc

@@ -11,17 +11,16 @@
 namespace dart {
 
 StackResource::StackResource() {
-  Isolate* isolate = Isolate::Current();
-  previous_ = isolate->top_resource();
-  isolate->set_top_resource(this);
+  isolate_ = Isolate::Current();
+  previous_ = isolate_->top_resource();
+  isolate_->set_top_resource(this);
 }
 
 
 StackResource::~StackResource() {
-  Isolate* isolate = Isolate::Current();
-  StackResource* top = isolate->top_resource();
+  StackResource* top = isolate_->top_resource();
   ASSERT(top == this);
-  isolate->set_top_resource(previous_);
+  isolate_->set_top_resource(previous_);
 }
 
 ZoneAllocated::~ZoneAllocated() {

runtime/vm/allocation.h

@@ -9,6 +9,9 @@
 
 namespace dart {
 
+// Forward declarations.
+class Isolate;
+
 // Stack allocated objects subclass from this base class. Objects of this type
 // cannot be allocated on either the C or object heaps. Destructors for objects
 // of this type will not be run unless the stack is unwound through normal
@@ -35,11 +38,14 @@ class StackResource {
   StackResource();
   virtual ~StackResource();
 
+  Isolate* isolate() const { return isolate_; }
+
   // The delete operator should be private instead of public, but unfortunately
   // the compiler complains when compiling the destructors for subclasses.
   void operator delete(void* pointer) { UNREACHABLE(); }
 
  private:
+  Isolate* isolate_;  // Current isolate for this stack resource.
   StackResource* previous_;
 
   void* operator new(uword size);

runtime/vm/handles.cc

@@ -70,45 +70,41 @@ int VMHandles::ZoneHandleCount() {
 
 
 HandleScope::HandleScope() : StackResource() {
-  Isolate* isolate = Isolate::Current();
-  ASSERT(isolate->no_handle_scope_depth() == 0);
-  VMHandles* handles = isolate->current_zone()->handles();
+  ASSERT(isolate()->no_handle_scope_depth() == 0);
+  VMHandles* handles = isolate()->current_zone()->handles();
   ASSERT(handles != NULL);
   saved_handle_block_ = handles->scoped_blocks_;
   saved_handle_slot_ = handles->scoped_blocks_->next_handle_slot();
 #if defined(DEBUG)
-  link_ = isolate->top_handle_scope();
-  isolate->set_top_handle_scope(this);
+  link_ = isolate()->top_handle_scope();
+  isolate()->set_top_handle_scope(this);
 #endif
 }
 
 
 HandleScope::~HandleScope() {
-  Isolate* isolate = Isolate::Current();
-  ASSERT(isolate->current_zone() != NULL);
-  VMHandles* handles = isolate->current_zone()->handles();
+  ASSERT(isolate()->current_zone() != NULL);
+  VMHandles* handles = isolate()->current_zone()->handles();
   ASSERT(handles != NULL);
   handles->scoped_blocks_ = saved_handle_block_;
   handles->scoped_blocks_->set_next_handle_slot(saved_handle_slot_);
 #if defined(DEBUG)
   handles->VerifyScopedHandleState();
   handles->ZapFreeScopedHandles();
-  ASSERT(isolate->top_handle_scope() == this);
-  isolate->set_top_handle_scope(link_);
+  ASSERT(isolate()->top_handle_scope() == this);
+  isolate()->set_top_handle_scope(link_);
 #endif
 }
 
 
 #if defined(DEBUG)
 NoHandleScope::NoHandleScope() : StackResource() {
-  Isolate* isolate = Isolate::Current();
-  isolate->IncrementNoHandleScopeDepth();
+  isolate()->IncrementNoHandleScopeDepth();
 }
 
 
 NoHandleScope::~NoHandleScope() {
-  Isolate* isolate = Isolate::Current();
-  isolate->DecrementNoHandleScopeDepth();
+  isolate()->DecrementNoHandleScopeDepth();
 }
 #endif  // defined(DEBUG)
 

runtime/vm/zone.cc

@@ -223,16 +223,14 @@ Zone::Zone()
   // Assert that there is no current zone as we only want to scope
   // zones when transitioning from generated dart code to dart VM
   // runtime code.
-  Isolate* isolate = Isolate::Current();
-  previous_ = isolate->current_zone();
-  Isolate::Current()->set_current_zone(this);
+  previous_ = isolate()->current_zone();
+  isolate()->set_current_zone(this);
 }
 
 
 Zone::~Zone() {
-  Isolate* isolate = Isolate::Current();
-  ASSERT(isolate->current_zone() == this);
-  isolate->set_current_zone(previous_);
+  ASSERT(isolate()->current_zone() == this);
+  isolate()->set_current_zone(previous_);
 }