Only flush code when there are no heap allocated locals in the scopeinfo.

When flushing code we can potentially flush code with a scopeinfo that
we later need to resolve variables. This makes an explicit check that
there are heap allocated locals in the scopeinfo.


Review URL: http://codereview.chromium.org/2836021

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4921 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/heap.cc

@@ -2264,6 +2264,12 @@ static void FlushCodeForFunction(SharedFunctionInfo* function_info) {
   ThreadManager::IterateArchivedThreads(&threadvisitor);
   if (threadvisitor.FoundCode()) return;
 
+  // Check that there are heap allocated locals in the scopeinfo. If
+  // there is, we are potentially using eval and need the scopeinfo
+  // for variable resolution.
+  if (ScopeInfo<>::HasHeapAllocatedLocals(function_info->code()))
+    return;
+
   HandleScope scope;
   // Compute the lazy compilable version of the code.
   function_info->set_code(*ComputeLazyCompile(function_info->length()));

src/scopeinfo.cc

@@ -407,6 +407,18 @@ int ScopeInfo<Allocator>::NumberOfContextSlots(Code* code) {
 }
 
 
+template<class Allocator>
+bool ScopeInfo<Allocator>::HasHeapAllocatedLocals(Code* code) {
+  if (code->sinfo_size() > 0) {
+    Object** p = ContextEntriesAddr(code);
+    int n;  // number of context slots;
+    ReadInt(p, &n);
+    return n > 0;
+  }
+  return false;
+}
+
+
 template<class Allocator>
 int ScopeInfo<Allocator>::StackSlotIndex(Code* code, String* name) {
   ASSERT(name->IsSymbol());

src/scopeinfo.h

@@ -112,6 +112,9 @@ class ScopeInfo BASE_EMBEDDED {
   // Return the number of context slots for code.
   static int NumberOfContextSlots(Code* code);
 
+  // Return if this has context slots besides MIN_CONTEXT_SLOTS;
+  static bool HasHeapAllocatedLocals(Code* code);
+
   // Lookup support for scope info embedded in Code objects. Returns
   // the stack slot index for a given slot name if the slot is
   // present; otherwise returns a value < 0. The name must be a symbol