Only flush SharedFunctionInfo optimized code cache when necessary

R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/14604007

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14650 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/deoptimizer-arm.cc

@@ -53,14 +53,13 @@ void Deoptimizer::DeoptimizeFunctionWithPreparedFunctionList(
   ASSERT(function->IsOptimized());
   ASSERT(function->FunctionsInFunctionListShareSameCode());
 
-  // The optimized code is going to be patched, so we cannot use it
-  // any more.  Play safe and reset the whole cache.
-  function->shared()->ClearOptimizedCodeMap("deoptimized function");
-
   // Get the optimized code.
   Code* code = function->code();
   Address code_start_address = code->instruction_start();
 
+  // The optimized code is going to be patched, so we cannot use it any more.
+  function->shared()->EvictFromOptimizedCodeMap(code, "deoptimized function");
+
   // Invalidate the relocation information, as it will become invalid by the
   // code patching below, and is not needed any more.
   code->InvalidateRelocation();

src/ia32/deoptimizer-ia32.cc

@@ -123,14 +123,13 @@ void Deoptimizer::DeoptimizeFunctionWithPreparedFunctionList(
   ASSERT(function->IsOptimized());
   ASSERT(function->FunctionsInFunctionListShareSameCode());
 
-  // The optimized code is going to be patched, so we cannot use it
-  // any more.  Play safe and reset the whole cache.
-  function->shared()->ClearOptimizedCodeMap("deoptimized function");
-
   // Get the optimized code.
   Code* code = function->code();
   Address code_start_address = code->instruction_start();
 
+  // The optimized code is going to be patched, so we cannot use it any more.
+  function->shared()->EvictFromOptimizedCodeMap(code, "deoptimized function");
+
   // We will overwrite the code's relocation info in-place. Relocation info
   // is written backward. The relocation info is the payload of a byte
   // array.  Later on we will slide this to the start of the byte array and

src/objects.cc

@@ -9034,7 +9034,7 @@ void SharedFunctionInfo::InstallFromOptimizedCodeMap(JSFunction* function,
 void SharedFunctionInfo::ClearOptimizedCodeMap(const char* reason) {
   if (!optimized_code_map()->IsSmi()) {
     if (FLAG_trace_opt) {
-      PrintF("[clearing optimizing code map (%s) for ", reason);
+      PrintF("[clearing entire optimizing code map (%s) for ", reason);
       ShortPrint();
       PrintF("]\n");
     }
@@ -9043,6 +9043,41 @@ void SharedFunctionInfo::ClearOptimizedCodeMap(const char* reason) {
 }
 
 
+void SharedFunctionInfo::EvictFromOptimizedCodeMap(Code* optimized_code,
+                                                   const char* reason) {
+  if (optimized_code_map()->IsSmi()) return;
+
+  int i;
+  bool removed_entry = false;
+  FixedArray* code_map = FixedArray::cast(optimized_code_map());
+  for (i = 0; i < code_map->length(); i += kEntryLength) {
+    ASSERT(code_map->get(i)->IsNativeContext());
+    if (Code::cast(code_map->get(i + 1)) == optimized_code) {
+      if (FLAG_trace_opt) {
+        PrintF("[clearing optimizing code map (%s) for ", reason);
+        ShortPrint();
+        PrintF("]\n");
+      }
+      removed_entry = true;
+      break;
+    }
+  }
+  while (i < (code_map->length() - kEntryLength)) {
+    code_map->set(i, code_map->get(i + kEntryLength));
+    code_map->set(i + 1, code_map->get(i + 1 + kEntryLength));
+    code_map->set(i + 2, code_map->get(i + 2 + kEntryLength));
+    i += kEntryLength;
+  }
+  if (removed_entry) {
+    if (code_map->length() > kEntryLength) {
+      RightTrimFixedArray<FROM_MUTATOR>(GetHeap(), code_map, kEntryLength);
+    } else {
+      ClearOptimizedCodeMap(reason);
+    }
+  }
+}
+
+
 bool JSFunction::CompileLazy(Handle<JSFunction> function,
                              ClearExceptionFlag flag) {
   bool result = true;

src/objects.h

@@ -5822,6 +5822,9 @@ class SharedFunctionInfo: public HeapObject {
   // Clear optimized code map.
   void ClearOptimizedCodeMap(const char* reason);
 
+  // Removed a specific optimized code object from the optimized code map.
+  void EvictFromOptimizedCodeMap(Code* optimized_code, const char* reason);
+
   // Add a new entry to the optimized code map.
   static void AddToOptimizedCodeMap(Handle<SharedFunctionInfo> shared,
                                     Handle<Context> native_context,

src/runtime.cc

@@ -7973,6 +7973,7 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_NotifyDeoptimized) {
   JavaScriptFrame* frame = it.frame();
   RUNTIME_ASSERT(frame->function()->IsJSFunction());
   Handle<JSFunction> function(JSFunction::cast(frame->function()), isolate);
+  Handle<Code> optimized_code(function->code());
   RUNTIME_ASSERT(type != Deoptimizer::EAGER || function->IsOptimized());
 
   // Avoid doing too much work when running with --always-opt and keep
@@ -8010,8 +8011,10 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_NotifyDeoptimized) {
   } else {
     Deoptimizer::DeoptimizeFunction(*function);
   }
-  // Flush optimized code cache for this function.
-  function->shared()->ClearOptimizedCodeMap("notify deoptimized");
+  // Evict optimized code for this function from the cache so that it doesn't
+  // get used for new closures.
+  function->shared()->EvictFromOptimizedCodeMap(*optimized_code,
+                                                "notify deoptimized");
 
   return isolate->heap()->undefined_value();
 }

src/x64/deoptimizer-x64.cc

@@ -55,13 +55,12 @@ void Deoptimizer::DeoptimizeFunctionWithPreparedFunctionList(
   ASSERT(function->IsOptimized());
   ASSERT(function->FunctionsInFunctionListShareSameCode());
 
-  // The optimized code is going to be patched, so we cannot use it
-  // any more.  Play safe and reset the whole cache.
-  function->shared()->ClearOptimizedCodeMap("deoptimized function");
-
   // Get the optimized code.
   Code* code = function->code();
 
+  // The optimized code is going to be patched, so we cannot use it any more.
+  function->shared()->EvictFromOptimizedCodeMap(code, "deoptimized function");
+
   // Invalidate the relocation information, as it will become invalid by the
   // code patching below, and is not needed any more.
   code->InvalidateRelocation();