Merge experimental/gc branch to the bleeding_edge.

src/debug.cc

Index: src/debug.cc
===================================================================
--- src/debug.cc	(revision 9327)
+++ src/debug.cc	(working copy)
@@ -401,15 +401,15 @@
   // Step in can only be prepared if currently positioned on an IC call,
   // construct call or CallFunction stub call.
   Address target = rinfo()->target_address();
-  Handle<Code> code(Code::GetCodeFromTargetAddress(target));
-  if (code->is_call_stub() || code->is_keyed_call_stub()) {
+  Handle<Code> target_code(Code::GetCodeFromTargetAddress(target));
+  if (target_code->is_call_stub() || target_code->is_keyed_call_stub()) {
     // Step in through IC call is handled by the runtime system. Therefore make
     // sure that the any current IC is cleared and the runtime system is
     // called. If the executing code has a debug break at the location change
     // the call in the original code as it is the code there that will be
     // executed in place of the debug break call.
-    Handle<Code> stub = ComputeCallDebugPrepareStepIn(code->arguments_count(),
-                                                      code->kind());
+    Handle<Code> stub = ComputeCallDebugPrepareStepIn(
+        target_code->arguments_count(), target_code->kind());
     if (IsDebugBreak()) {
       original_rinfo()->set_target_address(stub->entry());
     } else {
@@ -419,7 +419,7 @@
 #ifdef DEBUG
     // All the following stuff is needed only for assertion checks so the code
     // is wrapped in ifdef.
-    Handle<Code> maybe_call_function_stub = code;
+    Handle<Code> maybe_call_function_stub = target_code;
     if (IsDebugBreak()) {
       Address original_target = original_rinfo()->target_address();
       maybe_call_function_stub =
@@ -436,8 +436,9 @@
     // Step in through CallFunction stub should also be prepared by caller of
     // this function (Debug::PrepareStep) which should flood target function
     // with breakpoints.
-    ASSERT(RelocInfo::IsConstructCall(rmode()) || code->is_inline_cache_stub()
-           || is_call_function_stub);
+    ASSERT(RelocInfo::IsConstructCall(rmode()) ||
+           target_code->is_inline_cache_stub() ||
+           is_call_function_stub);
 #endif
   }
 }
@@ -474,11 +475,11 @@
   RelocInfo::Mode mode = rmode();
   if (RelocInfo::IsCodeTarget(mode)) {
     Address target = rinfo()->target_address();
-    Handle<Code> code(Code::GetCodeFromTargetAddress(target));
+    Handle<Code> target_code(Code::GetCodeFromTargetAddress(target));
 
     // Patch the code to invoke the builtin debug break function matching the
     // calling convention used by the call site.
-    Handle<Code> dbgbrk_code(Debug::FindDebugBreak(code, mode));
+    Handle<Code> dbgbrk_code(Debug::FindDebugBreak(target_code, mode));
     rinfo()->set_target_address(dbgbrk_code->entry());
   }
 }
@@ -1997,9 +1998,10 @@
 
   // Perform two GCs to get rid of all unreferenced scripts. The first GC gets
   // rid of all the cached script wrappers and the second gets rid of the
-  // scripts which are no longer referenced.
-  heap->CollectAllGarbage(false);
-  heap->CollectAllGarbage(false);
+  // scripts which are no longer referenced.  The second also sweeps precisely,
+  // which saves us doing yet another GC to make the heap iterable.
+  heap->CollectAllGarbage(Heap::kNoGCFlags);
+  heap->CollectAllGarbage(Heap::kMakeHeapIterableMask);
 
   ASSERT(script_cache_ == NULL);
   script_cache_ = new ScriptCache();
@@ -2007,6 +2009,8 @@
   // Scan heap for Script objects.
   int count = 0;
   HeapIterator iterator;
+  AssertNoAllocation no_allocation;
+
   for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {
     if (obj->IsScript() && Script::cast(obj)->HasValidSource()) {
       script_cache_->Add(Handle<Script>(Script::cast(obj)));
@@ -2047,7 +2051,7 @@
 
   // Perform GC to get unreferenced scripts evicted from the cache before
   // returning the content.
-  isolate_->heap()->CollectAllGarbage(false);
+  isolate_->heap()->CollectAllGarbage(Heap::kNoGCFlags);
 
   // Get the scripts from the cache.
   return script_cache_->GetScripts();