Factor out common code from platform-specific deoptimization. Fix Deoptimizer not to need to partit…

src/deoptimizer.cc

Index: src/deoptimizer.cc
diff --git a/src/deoptimizer.cc b/src/deoptimizer.cc
index fd7c2829adde7dc9ab9799385bfcb11282af0fb2..54b195dddfa2effb08dadb765be7a5d032fe16df 100644
--- a/src/deoptimizer.cc
+++ b/src/deoptimizer.cc
@@ -331,34 +331,47 @@ void Deoptimizer::VisitAllOptimizedFunctions(
 
 
 // Removes the functions selected by the given filter from the optimized
-// function list of the given context and partitions the removed functions
-// into one or more lists such that all functions in a list share the same
-// code. The head of each list is written in the deoptimizing_functions field
-// of the corresponding code object.
-// The found code objects are returned in the given zone list.
-static void PartitionOptimizedFunctions(Context* context,
-                                        OptimizedFunctionFilter* filter,
-                                        ZoneList<Code*>* partitions,
-                                        Zone* zone,
-                                        Object* undefined) {
+// function list of the given context and adds their code to the list of
+// code objects to be deoptimized.
+static void SelectCodeToDeoptimize(Context* context,
+                                   OptimizedFunctionFilter* filter,
+                                   ZoneList<Code*>* codes,
+                                   Zone* zone,
+                                   Object* undefined) {
   DisallowHeapAllocation no_allocation;
   Object* current = context->get(Context::OPTIMIZED_FUNCTIONS_LIST);
   Object* remainder_head = undefined;
   Object* remainder_tail = undefined;
-  ASSERT_EQ(0, partitions->length());
+
+  // TODO(titzer): rewrite to not modify unselected functions.

[Michael Starzinger, 2013/07/24 09:24:57]

I am unsure about this TODO, what does this imply?

   while (current != undefined) {
     JSFunction* function = JSFunction::cast(current);
     current = function->next_function_link();
     if (filter->TakeFunction(function)) {
+      // Extract this function from the context's list and remember the code.
       Code* code = function->code();
-      if (code->deoptimizing_functions() == undefined) {
-        partitions->Add(code, zone);
+      ASSERT(code->kind() == Code::OPTIMIZED_FUNCTION);
+      if (code->marked_for_deoptimization()) {
+        ASSERT(codes->Contains(code));
       } else {
-        ASSERT(partitions->Contains(code));
+        code->set_marked_for_deoptimization(true);
+        codes->Add(code, zone);
+      }
+      SharedFunctionInfo* shared = function->shared();
+      // Replace the function's code with the shared code.
+      function->set_code(shared->code());
+      // Evict the code from the optimized code map.
+      shared->EvictFromOptimizedCodeMap(code, "deoptimized function");
+      // Remove the function from the optimized functions list.
+      function->set_next_function_link(undefined);
+
+      if (FLAG_trace_deopt) {
+        PrintF("[forced deoptimization: ");
+        function->PrintName();
+        PrintF(" / %" V8PRIxPTR "]\n", reinterpret_cast<intptr_t>(function));
       }
-      function->set_next_function_link(code->deoptimizing_functions());
-      code->set_deoptimizing_functions(function);
     } else {
+      // Don't select this function; link it back into the list.
       if (remainder_head == undefined) {
         remainder_head = function;
       } else {
@@ -421,19 +434,11 @@ void Deoptimizer::DeoptimizeGlobalObject(JSObject* object) {
 
 
 void Deoptimizer::DeoptimizeFunction(JSFunction* function) {
-  if (!function->IsOptimized()) return;
   Code* code = function->code();
-  Context* context = function->context()->native_context();
-  Isolate* isolate = context->GetIsolate();
-  Object* undefined = isolate->heap()->undefined_value();
-  Zone zone(isolate);
-  ZoneList<Code*> codes(1, &zone);
+  if (code->kind() != Code::OPTIMIZED_FUNCTION) return;
   DeoptimizeWithMatchingCodeFilter filter(code);
-  PartitionOptimizedFunctions(context, &filter, &codes, &zone, undefined);
-  ASSERT_EQ(1, codes.length());
-  DeoptimizeFunctionWithPreparedFunctionList(
-      JSFunction::cast(codes.at(0)->deoptimizing_functions()));
-  codes.at(0)->set_deoptimizing_functions(undefined);
+  DeoptimizeAllFunctionsForContext(
+      function->context()->native_context(), &filter);
 }
 
 
@@ -443,12 +448,10 @@ void Deoptimizer::DeoptimizeAllFunctionsForContext(
   Isolate* isolate = context->GetIsolate();
   Object* undefined = isolate->heap()->undefined_value();
   Zone zone(isolate);
-  ZoneList<Code*> codes(1, &zone);
-  PartitionOptimizedFunctions(context, filter, &codes, &zone, undefined);
-  for (int i = 0; i < codes.length(); ++i) {
-    DeoptimizeFunctionWithPreparedFunctionList(
-        JSFunction::cast(codes.at(i)->deoptimizing_functions()));
-    codes.at(i)->set_deoptimizing_functions(undefined);
+  ZoneList<Code*> codes(4, &zone);
+  SelectCodeToDeoptimize(context, filter, &codes, &zone, undefined);
+  for (int i = 0; i < codes.length(); i++) {
+    DeoptimizeCode(isolate, codes.at(i));
   }
 }
 
@@ -466,6 +469,63 @@ void Deoptimizer::DeoptimizeAllFunctionsWith(Isolate* isolate,
 }
 
 
+class DeoptimizeMarkedCodeFilter : public OptimizedFunctionFilter {

[Michael Starzinger, 2013/07/24 09:24:57]

nit: Can we move this up to the other filters so that they are grouped together?

+ public:
+  virtual bool TakeFunction(JSFunction* function) {
+    return function->code()->marked_for_deoptimization();
+  }
+};
+
+
+void Deoptimizer::DeoptimizeCodeList(Isolate* isolate, ZoneList<Code*>* codes) {
+  if (codes->length() == 0) return;  // Nothing to do.
+
+  // Mark the code; any functions refering to this code will be selected.
+  for (int i = 0; i < codes->length(); i++) {
+    ASSERT(!codes->at(i)->marked_for_deoptimization());
+    codes->at(i)->set_marked_for_deoptimization(true);
+  }
+
+  // For all contexts, remove optimized functions that refer to the selected
+  // code from the optimized function lists.
+  Object* undefined = isolate->heap()->undefined_value();
+  Zone zone(isolate);
+  Object* list = isolate->heap()->native_contexts_list();
+  DeoptimizeMarkedCodeFilter filter;
+  while (!list->IsUndefined()) {
+    Context* context = Context::cast(list);
+    // Note that selecting code unlinks the functions that refer to it.
+    SelectCodeToDeoptimize(context, &filter, codes, &zone, undefined);
+    list = Context::cast(context)->get(Context::NEXT_CONTEXT_LINK);
+  }
+
+  // Now deoptimize all the code.
+  for (int i = 0; i < codes->length(); i++) {
+    DeoptimizeCode(isolate, codes->at(i));
+  }
+}
+
+
+void Deoptimizer::DeoptimizeCode(Isolate* isolate, Code* code) {
+  HandleScope scope(isolate);
+  DisallowHeapAllocation nha;
+
+  // Do platform-specific patching of the optimized code.
+  PatchCodeForDeoptimization(isolate, code);
+
+  // Add the deoptimizing code to the list.
+  DeoptimizingCodeListNode* node = new DeoptimizingCodeListNode(code);
+  DeoptimizerData* data = isolate->deoptimizer_data();
+  node->set_next(data->deoptimizing_code_list_);
+  data->deoptimizing_code_list_ = node;
+
+  // We might be in the middle of incremental marking with compaction.
+  // Tell collector to treat this code object in a special way and
+  // ignore all slots that might have been recorded on it.
+  isolate->heap()->mark_compact_collector()->InvalidateCode(code);
+}
+
+
 void Deoptimizer::HandleWeakDeoptimizedCode(v8::Isolate* isolate,
                                             v8::Persistent<v8::Value>* obj,
                                             void* parameter) {
@@ -2569,21 +2629,6 @@ void Deoptimizer::EnsureCodeForDeoptimizationEntry(Isolate* isolate,
 }
 
 
-void Deoptimizer::ReplaceCodeForRelatedFunctions(JSFunction* function,
-                                                 Code* code) {
-  SharedFunctionInfo* shared = function->shared();
-  Object* undefined = function->GetHeap()->undefined_value();
-  Object* current = function;
-
-  while (current != undefined) {
-    JSFunction* func = JSFunction::cast(current);
-    current = func->next_function_link();
-    func->set_code(shared->code());
-    func->set_next_function_link(undefined);
-  }
-}
-
-
 FrameDescription::FrameDescription(uint32_t frame_size,
                                    JSFunction* function)
     : frame_size_(frame_size),