Ensure that non-optimized code objects are not flushed for inlined functions.

src/mark-compact.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 601 matching lines @@
       : isolate_(isolate),
         jsfunction_candidates_head_(NULL),
         shared_function_info_candidates_head_(NULL) {}
 
   void AddCandidate(SharedFunctionInfo* shared_info) {
     SetNextCandidate(shared_info, shared_function_info_candidates_head_);
     shared_function_info_candidates_head_ = shared_info;
   }
 
   void AddCandidate(JSFunction* function) {
-    ASSERT(function->unchecked_code() ==
-           function->unchecked_shared()->unchecked_code());
+    ASSERT(function->code() == function->shared()->code());
 
     SetNextCandidate(function, jsfunction_candidates_head_);
     jsfunction_candidates_head_ = function;
   }
 
   void ProcessCandidates() {
     ProcessSharedFunctionInfoCandidates();
     ProcessJSFunctionCandidates();
   }
 
  private:
   void ProcessJSFunctionCandidates() {
     Code* lazy_compile = isolate_->builtins()->builtin(Builtins::kLazyCompile);
 
     JSFunction* candidate = jsfunction_candidates_head_;
     JSFunction* next_candidate;
     while (candidate != NULL) {
       next_candidate = GetNextCandidate(candidate);
 
-      SharedFunctionInfo* shared = candidate->unchecked_shared();
+      SharedFunctionInfo* shared = candidate->shared();
 
-      Code* code = shared->unchecked_code();
+      Code* code = shared->code();
       MarkBit code_mark = Marking::MarkBitFrom(code);
       if (!code_mark.Get()) {
         shared->set_code(lazy_compile);
         candidate->set_code(lazy_compile);
       } else {
-        candidate->set_code(shared->unchecked_code());
+        candidate->set_code(shared->code());
       }
 
       // We are in the middle of a GC cycle so the write barrier in the code
       // setter did not record the slot update and we have to do that manually.
       Address slot = candidate->address() + JSFunction::kCodeEntryOffset;
       Code* target = Code::cast(Code::GetObjectFromEntryAddress(slot));
       isolate_->heap()->mark_compact_collector()->
           RecordCodeEntrySlot(slot, target);
 
       candidate = next_candidate;
     }
 
     jsfunction_candidates_head_ = NULL;
   }
 
 
   void ProcessSharedFunctionInfoCandidates() {
     Code* lazy_compile = isolate_->builtins()->builtin(Builtins::kLazyCompile);
 
     SharedFunctionInfo* candidate = shared_function_info_candidates_head_;
     SharedFunctionInfo* next_candidate;
     while (candidate != NULL) {
       next_candidate = GetNextCandidate(candidate);
       SetNextCandidate(candidate, NULL);
 
-      Code* code = candidate->unchecked_code();
+      Code* code = candidate->code();
       MarkBit code_mark = Marking::MarkBitFrom(code);
       if (!code_mark.Get()) {
         candidate->set_code(lazy_compile);
       }
 
       candidate = next_candidate;
     }
 
     shared_function_info_candidates_head_ = NULL;
   }
 
   static JSFunction** GetNextCandidateField(JSFunction* candidate) {
     return reinterpret_cast<JSFunction**>(
         candidate->address() + JSFunction::kCodeEntryOffset);
   }
 
   static JSFunction* GetNextCandidate(JSFunction* candidate) {
     return *GetNextCandidateField(candidate);
   }
 
   static void SetNextCandidate(JSFunction* candidate,
                                JSFunction* next_candidate) {
     *GetNextCandidateField(candidate) = next_candidate;
   }
 
   static SharedFunctionInfo** GetNextCandidateField(
       SharedFunctionInfo* candidate) {
-    Code* code = candidate->unchecked_code();
+    Code* code = candidate->code();
     return reinterpret_cast<SharedFunctionInfo**>(
         code->address() + Code::kNextCodeFlushingCandidateOffset);
   }
 
   static SharedFunctionInfo* GetNextCandidate(SharedFunctionInfo* candidate) {
     return *GetNextCandidateField(candidate);
   }
 
   static void SetNextCandidate(SharedFunctionInfo* candidate,
                                SharedFunctionInfo* next_candidate) {
@@ skipping 314 matching lines @@
   static const int kRegExpCodeThreshold = 5;
 
   inline static bool HasSourceCode(Heap* heap, SharedFunctionInfo* info) {
     Object* undefined = heap->undefined_value();
     return (info->script() != undefined) &&
         (reinterpret_cast<Script*>(info->script())->source() != undefined);
   }
 
 
   inline static bool IsCompiled(JSFunction* function) {
-    return function->unchecked_code() !=
+    return function->code() !=
         function->GetIsolate()->builtins()->builtin(Builtins::kLazyCompile);
   }
 
   inline static bool IsCompiled(SharedFunctionInfo* function) {
-    return function->unchecked_code() !=
+    return function->code() !=
         function->GetIsolate()->builtins()->builtin(Builtins::kLazyCompile);
   }
 
   inline static bool IsFlushable(Heap* heap, JSFunction* function) {
     SharedFunctionInfo* shared_info = function->unchecked_shared();
 
     // Code is either on stack, in compilation cache or referenced
     // by optimized version of function.
-    MarkBit code_mark =
-        Marking::MarkBitFrom(function->unchecked_code());
+    MarkBit code_mark = Marking::MarkBitFrom(function->code());
     if (code_mark.Get()) {
       if (!Marking::MarkBitFrom(shared_info).Get()) {
         shared_info->set_code_age(0);
       }
       return false;
     }
 
     // We do not flush code for optimized functions.
-    if (function->code() != shared_info->unchecked_code()) {
+    if (function->code() != shared_info->code()) {
       return false;
     }
 
     return IsFlushable(heap, shared_info);
   }
 
   inline static bool IsFlushable(Heap* heap, SharedFunctionInfo* shared_info) {
     // Code is either on stack, in compilation cache or referenced
     // by optimized version of function.
     MarkBit code_mark =
-        Marking::MarkBitFrom(shared_info->unchecked_code());
+        Marking::MarkBitFrom(shared_info->code());
     if (code_mark.Get()) {
       return false;
     }
 
     // The function must be compiled and have the source code available,
     // to be able to recompile it in case we need the function again.
     if (!(shared_info->is_compiled() && HasSourceCode(heap, shared_info))) {
       return false;
     }
 
     // We never flush code for Api functions.
     Object* function_data = shared_info->function_data();
-    if (function_data->IsFunctionTemplateInfo()) return false;
+    if (function_data->IsFunctionTemplateInfo()) {
+      return false;
+    }
 
     // Only flush code for functions.
-    if (shared_info->code()->kind() != Code::FUNCTION) return false;
+    if (shared_info->code()->kind() != Code::FUNCTION) {
+      return false;
+    }
 
     // Function must be lazy compilable.
-    if (!shared_info->allows_lazy_compilation()) return false;
+    if (!shared_info->allows_lazy_compilation()) {
+      return false;
+    }
 
     // If this is a full script wrapped in a function we do no flush the code.
-    if (shared_info->is_toplevel()) return false;
+    if (shared_info->is_toplevel()) {
+      return false;
+    }
 
     // Age this shared function info.
     if (shared_info->code_age() < kCodeAgeThreshold) {
       shared_info->set_code_age(shared_info->code_age() + 1);
       return false;
     }
 
     return true;
   }
 
@@ skipping 152 matching lines @@
     }
 
     JSFunction* jsfunction = reinterpret_cast<JSFunction*>(object);
     // The function must have a valid context and not be a builtin.
     bool flush_code_candidate = false;
     if (IsValidNotBuiltinContext(jsfunction->unchecked_context())) {
       flush_code_candidate = FlushCodeForFunction(heap, jsfunction);
     }
 
     if (!flush_code_candidate) {
-      Code* code = jsfunction->unchecked_shared()->unchecked_code();
+      Code* code = jsfunction->shared()->code();
       MarkBit code_mark = Marking::MarkBitFrom(code);
-      heap->mark_compact_collector()->MarkObject(code, code_mark);
+      collector->MarkObject(code, code_mark);
 
-      if (jsfunction->unchecked_code()->kind() == Code::OPTIMIZED_FUNCTION) {
-        // For optimized functions we should retain both non-optimized version
-        // of it's code and non-optimized version of all inlined functions.
-        // This is required to support bailing out from inlined code.
-        DeoptimizationInputData* data =
-            reinterpret_cast<DeoptimizationInputData*>(
-                jsfunction->unchecked_code()->unchecked_deoptimization_data());
-
-        FixedArray* literals = data->UncheckedLiteralArray();
-
-        for (int i = 0, count = data->InlinedFunctionCount()->value();
-             i < count;
-             i++) {
-          JSFunction* inlined = reinterpret_cast<JSFunction*>(literals->get(i));
-          Code* inlined_code = inlined->unchecked_shared()->unchecked_code();
-          MarkBit inlined_code_mark =
-              Marking::MarkBitFrom(inlined_code);
-          heap->mark_compact_collector()->MarkObject(
-              inlined_code, inlined_code_mark);
-        }
+      if (jsfunction->code()->kind() == Code::OPTIMIZED_FUNCTION) {
+        collector->MarkInlinedFunctionsCode(jsfunction->code());
       }
     }
 
     VisitJSFunctionFields(map,
                           reinterpret_cast<JSFunction*>(object),
                           flush_code_candidate);
   }
 
 
   static void VisitJSFunction(Map* map, HeapObject* object) {
@@ skipping 104 matching lines @@
   Heap* heap_;
 };
 
 
 class CodeMarkingVisitor : public ThreadVisitor {
  public:
   explicit CodeMarkingVisitor(MarkCompactCollector* collector)
       : collector_(collector) {}
 
   void VisitThread(Isolate* isolate, ThreadLocalTop* top) {
-    for (StackFrameIterator it(isolate, top); !it.done(); it.Advance()) {
-      Code* code = it.frame()->unchecked_code();
-      MarkBit code_bit = Marking::MarkBitFrom(code);
-      collector_->MarkObject(it.frame()->unchecked_code(), code_bit);
-    }
+    collector_->PrepareThreadForCodeFlushing(isolate, top);
   }
 
  private:
   MarkCompactCollector* collector_;
 };
 
 
 class SharedFunctionInfoMarkingVisitor : public ObjectVisitor {
  public:
   explicit SharedFunctionInfoMarkingVisitor(MarkCompactCollector* collector)
       : collector_(collector) {}
 
   void VisitPointers(Object** start, Object** end) {
     for (Object** p = start; p < end; p++) VisitPointer(p);
   }
 
   void VisitPointer(Object** slot) {
     Object* obj = *slot;
     if (obj->IsSharedFunctionInfo()) {
       SharedFunctionInfo* shared = reinterpret_cast<SharedFunctionInfo*>(obj);
       MarkBit shared_mark = Marking::MarkBitFrom(shared);
-      MarkBit code_mark = Marking::MarkBitFrom(shared->unchecked_code());
-      collector_->MarkObject(shared->unchecked_code(), code_mark);
+      MarkBit code_mark = Marking::MarkBitFrom(shared->code());
+      collector_->MarkObject(shared->code(), code_mark);
       collector_->MarkObject(shared, shared_mark);
     }
   }
 
  private:
   MarkCompactCollector* collector_;
 };
 
 
+void MarkCompactCollector::MarkInlinedFunctionsCode(Code* code) {
+  // For optimized functions we should retain both non-optimized version
+  // of it's code and non-optimized version of all inlined functions.
+  // This is required to support bailing out from inlined code.
+  DeoptimizationInputData* data =
+      DeoptimizationInputData::cast(code->deoptimization_data());
+
+  FixedArray* literals = data->LiteralArray();
+
+  for (int i = 0, count = data->InlinedFunctionCount()->value();
+       i < count;
+       i++) {
+    JSFunction* inlined = JSFunction::cast(literals->get(i));
+    Code* inlined_code = inlined->shared()->code();
+    MarkBit inlined_code_mark = Marking::MarkBitFrom(inlined_code);
+    MarkObject(inlined_code, inlined_code_mark);
+  }
+}
+
+
+void MarkCompactCollector::PrepareThreadForCodeFlushing(Isolate* isolate,
+                                                        ThreadLocalTop* top) {
+  for (StackFrameIterator it(isolate, top); !it.done(); it.Advance()) {
+    // Note: for the frame that has a pending lazy deoptimization
+    // StackFrame::unchecked_code will return a non-optimized code object for
+    // the outermost function and StackFrame::LookupCode will return
+    // actual optimized code object.
+    StackFrame* frame = it.frame();
+    Code* code = frame->unchecked_code();
+    MarkBit code_mark = Marking::MarkBitFrom(code);
+    MarkObject(code, code_mark);
+    if (frame->is_optimized()) {
+      MarkInlinedFunctionsCode(frame->LookupCode());
+    }
+  }
+}
+
+
 void MarkCompactCollector::PrepareForCodeFlushing() {
   ASSERT(heap() == Isolate::Current()->heap());
 
   // TODO(1609) Currently incremental marker does not support code flushing.
   if (!FLAG_flush_code || was_marked_incrementally_) {
     EnableCodeFlushing(false);
     return;
   }
 
 #ifdef ENABLE_DEBUGGER_SUPPORT
   if (heap()->isolate()->debug()->IsLoaded() ||
       heap()->isolate()->debug()->has_break_points()) {
     EnableCodeFlushing(false);
     return;
   }
 #endif
 
   EnableCodeFlushing(true);
 
   // Ensure that empty descriptor array is marked. Method MarkDescriptorArray
   // relies on it being marked before any other descriptor array.
   HeapObject* descriptor_array = heap()->empty_descriptor_array();
   MarkBit descriptor_array_mark = Marking::MarkBitFrom(descriptor_array);
   MarkObject(descriptor_array, descriptor_array_mark);
 
   // Make sure we are not referencing the code from the stack.
   ASSERT(this == heap()->mark_compact_collector());
-  for (StackFrameIterator it; !it.done(); it.Advance()) {
-    Code* code = it.frame()->unchecked_code();
-    MarkBit code_mark = Marking::MarkBitFrom(code);
-    MarkObject(code, code_mark);
-  }
+  PrepareThreadForCodeFlushing(heap()->isolate(),
+                               heap()->isolate()->thread_local_top());
 
   // Iterate the archived stacks in all threads to check if
   // the code is referenced.
   CodeMarkingVisitor code_marking_visitor(this);
   heap()->isolate()->thread_manager()->IterateArchivedThreads(
       &code_marking_visitor);
 
   SharedFunctionInfoMarkingVisitor visitor(this);
   heap()->isolate()->compilation_cache()->IterateFunctions(&visitor);
   heap()->isolate()->handle_scope_implementer()->Iterate(&visitor);
@@ skipping 2388 matching lines @@
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 
 
 } }  // namespace v8::internal