[turbofan] Implement sharing of context-independent code.

This allows context-independent code generated by TurboFan to be cached
in the optimized code map and reused across native contexts. Note that
currently this cache is still flushed at GC time.

R=bmeurer@chromium.org,mvstanton@chromium.org
TEST=cctest/test-compiler/OptimizedCodeSharing

Review URL: https://codereview.chromium.org/1208013002

Cr-Commit-Position: refs/heads/master@{#29313}

src/code-stubs-hydrogen.cc

@@ -93,6 +93,8 @@ class CodeStubGraphBuilderBase : public HGraphBuilder {
                                          IfBuilder* builder,
                                          HValue* optimized_map,
                                          HValue* map_index);
+  void BuildInstallOptimizedCode(HValue* js_function, HValue* native_context,
+                                 HValue* code_object, HValue* literals);
   void BuildInstallCode(HValue* js_function, HValue* shared_info);
 
   HInstruction* LoadFromOptimizedCodeMap(HValue* optimized_map,
@@ -1651,6 +1653,16 @@ void CodeStubGraphBuilderBase::BuildCheckAndInstallOptimizedCode(
   HValue* literals = LoadFromOptimizedCodeMap(optimized_map,
       map_index, SharedFunctionInfo::kLiteralsOffset);
 
+  BuildInstallOptimizedCode(js_function, native_context, code_object, literals);
+
+  // The builder continues in the "then" after this function.
+}
+
+
+void CodeStubGraphBuilderBase::BuildInstallOptimizedCode(HValue* js_function,
+                                                         HValue* native_context,
+                                                         HValue* code_object,
+                                                         HValue* literals) {
   Counters* counters = isolate()->counters();
   AddIncrementCounter(counters->fast_new_closure_install_optimized());
 
@@ -1673,8 +1685,6 @@ void CodeStubGraphBuilderBase::BuildCheckAndInstallOptimizedCode(
   Add<HStoreNamedField>(native_context,
            HObjectAccess::ForContextSlot(Context::OPTIMIZED_FUNCTIONS_LIST),
            js_function);
-
-  // The builder continues in the "then" after this function.
 }
 
 
@@ -1712,6 +1722,7 @@ void CodeStubGraphBuilderBase::BuildInstallFromOptimizedCodeMap(
     HValue* shared_info,
     HValue* native_context) {
   Counters* counters = isolate()->counters();
+  Factory* factory = isolate()->factory();
   IfBuilder is_optimized(this);
   HInstruction* optimized_map = Add<HLoadNamedField>(
       shared_info, nullptr, HObjectAccess::ForOptimizedCodeMap());
@@ -1764,18 +1775,34 @@ void CodeStubGraphBuilderBase::BuildInstallFromOptimizedCodeMap(
       }
       loop_builder.EndBody();
 
-      // If slot_iterator equals first entry index, then we failed to find and
-      // install optimized code
+      // If slot_iterator equals first entry index, then we failed to find a
+      // context-dependent code and try context-independent code next.
       IfBuilder no_optimized_code_check(this);
       no_optimized_code_check.If<HCompareNumericAndBranch>(
           slot_iterator, first_entry_index, Token::EQ);
       no_optimized_code_check.Then();
       {
-        // Store the unoptimized code
+        IfBuilder shared_code_check(this);
+        HValue* shared_code = Add<HLoadNamedField>(
+            optimized_map, nullptr,
+            HObjectAccess::ForOptimizedCodeMapSharedCode());
+        shared_code_check.IfNot<HCompareObjectEqAndBranch>(
+            shared_code, graph()->GetConstantUndefined());
+        shared_code_check.Then();
+        {
+          // Store the context-independent optimized code.
+          HValue* literals = Add<HConstant>(factory->empty_fixed_array());
+          BuildInstallOptimizedCode(js_function, native_context, shared_code,
+                                    literals);
+        }
+        shared_code_check.Else();
+        {
+          // Store the unoptimized code.
           BuildInstallCode(js_function, shared_info);
         }
       }
     }
+  }
 }
 
 

src/compiler.cc

@@ -714,17 +714,28 @@ static void InsertCodeIntoOptimizedCodeMap(CompilationInfo* info) {
   if (code->is_turbofanned() && info->is_context_specializing()) return;
 
   // Do not cache bound functions.
-  if (info->closure()->shared()->bound()) return;
+  Handle<JSFunction> function = info->closure();
+  if (function->shared()->bound()) return;
 
-  // Cache optimized code.
+  // Cache optimized context-specific code.
   if (FLAG_cache_optimized_code) {
-    Handle<JSFunction> function = info->closure();
     Handle<SharedFunctionInfo> shared(function->shared());
     Handle<FixedArray> literals(function->literals());
     Handle<Context> native_context(function->context()->native_context());
     SharedFunctionInfo::AddToOptimizedCodeMap(shared, native_context, code,
                                               literals, info->osr_ast_id());
   }
+
+  // Do not cache context-independent code compiled for OSR.
+  if (code->is_turbofanned() && info->is_osr()) return;
+
+  // Cache optimized context-independent code.
+  if (FLAG_turbo_cache_shared_code && code->is_turbofanned()) {
+    DCHECK(!info->is_context_specializing());
+    DCHECK(info->osr_ast_id().IsNone());
+    Handle<SharedFunctionInfo> shared(function->shared());
+    SharedFunctionInfo::AddSharedCodeToOptimizedCodeMap(shared, code);
+  }
 }
 
 

src/factory.cc

@@ -1390,6 +1390,7 @@ Handle<JSFunction> Factory::NewFunctionFromSharedFunctionInfo(
 
   if (cached.literals == nullptr && !info->bound()) {
     int number_of_literals = info->num_literals();
+    // TODO(mstarzinger): Consider sharing the newly created literals array.
     Handle<FixedArray> literals = NewFixedArray(number_of_literals, pretenure);
     result->set_literals(*literals);
   }

src/flag-definitions.h

@@ -430,6 +430,7 @@ DEFINE_BOOL(turbo_stress_loop_peeling, false,
             "stress loop peeling optimization")
 DEFINE_BOOL(turbo_cf_optimization, true, "optimize control flow in TurboFan")
 DEFINE_BOOL(turbo_frame_elision, true, "elide frames in TurboFan")
+DEFINE_BOOL(turbo_cache_shared_code, false, "cache context-independent code")
 
 DEFINE_INT(typed_array_max_size_in_heap, 64,
            "threshold for in-heap typed array")

src/hydrogen-instructions.h

@@ -5980,6 +5980,11 @@ class HObjectAccess final {
                          SharedFunctionInfo::kOptimizedCodeMapOffset);
   }
 
+  static HObjectAccess ForOptimizedCodeMapSharedCode() {
+    return HObjectAccess(kInobject, FixedArray::OffsetOfElementAt(
+                                        SharedFunctionInfo::kSharedCodeIndex));
+  }
+
   static HObjectAccess ForFunctionContextPointer() {
     return HObjectAccess(kInobject, JSFunction::kContextOffset);
   }

src/objects.cc

@@ -9568,6 +9568,17 @@ Handle<JSFunction> JSFunction::CloneClosure(Handle<JSFunction> function) {
 }
 
 
+void SharedFunctionInfo::AddSharedCodeToOptimizedCodeMap(
+    Handle<SharedFunctionInfo> shared, Handle<Code> code) {
+  Isolate* isolate = shared->GetIsolate();
+  DCHECK(code->kind() == Code::OPTIMIZED_FUNCTION);
+  Handle<Object> value(shared->optimized_code_map(), isolate);
+  if (value->IsSmi()) return;  // Empty code maps are unsupported.
+  Handle<FixedArray> code_map = Handle<FixedArray>::cast(value);
+  code_map->set(kSharedCodeIndex, *code);
+}
+
+
 void SharedFunctionInfo::AddToOptimizedCodeMap(
     Handle<SharedFunctionInfo> shared,
     Handle<Context> native_context,
@@ -9584,7 +9595,6 @@ void SharedFunctionInfo::AddToOptimizedCodeMap(
   if (value->IsSmi()) {
     // No optimized code map.
     DCHECK_EQ(0, Smi::cast(*value)->value());
-    // Create 3 entries per context {context, code, literals}.
     new_code_map = isolate->factory()->NewFixedArray(kInitialLength);
     old_length = kEntriesStart;
   } else {
@@ -9672,6 +9682,15 @@ void SharedFunctionInfo::EvictFromOptimizedCodeMap(Code* optimized_code,
       dst += kEntryLength;
     }
   }
+  if (code_map->get(kSharedCodeIndex) == optimized_code) {
+    // Evict context-independent code as well.
+    code_map->set_undefined(kSharedCodeIndex);
+    if (FLAG_trace_opt) {
+      PrintF("[evicting entry from optimizing code map (%s) for ", reason);
+      ShortPrint();
+      PrintF(" (context-independent code)]\n");
+    }
+  }
   if (dst != length) {
     // Always trim even when array is cleared because of heap verifier.
     GetHeap()->RightTrimFixedArray<Heap::CONCURRENT_TO_SWEEPER>(code_map,
@@ -10659,6 +10678,10 @@ CodeAndLiterals SharedFunctionInfo::SearchOptimizedCodeMap(
                 FixedArray::cast(optimized_code_map->get(i + kLiteralsOffset))};
       }
     }
+    Object* shared_code = optimized_code_map->get(kSharedCodeIndex);
+    if (shared_code->IsCode() && osr_ast_id.IsNone()) {
+      return {Code::cast(shared_code), nullptr};
+    }
     if (FLAG_trace_opt) {
       PrintF("[didn't find optimized code in optimized code map for ");
       ShortPrint();

src/objects.h

@@ -6555,7 +6555,7 @@ enum BuiltinFunctionId {
 
 
 // Result of searching in an optimized code map of a SharedFunctionInfo. Note
-// that {code == nullptr} indicates that no entry has been found.
+// that both {code} and {literals} can be NULL to pass search result status.
 struct CodeAndLiterals {
   Code* code;            // Cached optimized code.
   FixedArray* literals;  // Cached literals array.
@@ -6578,7 +6578,8 @@ class SharedFunctionInfo: public HeapObject {
   DECL_ACCESSORS(optimized_code_map, Object)
 
   // Returns entry from optimized code map for specified context and OSR entry.
-  // Note that {code == nullptr} indicates no matching entry has been found.
+  // Note that {code == nullptr} indicates no matching entry has been found,
+  // whereas {literals == nullptr} indicates the code is context-independent.
   CodeAndLiterals SearchOptimizedCodeMap(Context* native_context,
                                          BailoutId osr_ast_id);
 
@@ -6588,20 +6589,14 @@ class SharedFunctionInfo: public HeapObject {
   // Removed a specific optimized code object from the optimized code map.
   void EvictFromOptimizedCodeMap(Code* optimized_code, const char* reason);
 
-  // Unconditionally clear the type feedback vector (including vector ICs).
-  void ClearTypeFeedbackInfo();
-
-  // Clear the type feedback vector with a more subtle policy at GC time.
-  void ClearTypeFeedbackInfoAtGCTime();
-
   // Trims the optimized code map after entries have been removed.
   void TrimOptimizedCodeMap(int shrink_by);
 
-  // Initialize a SharedFunctionInfo from a parsed function literal.
-  static void InitFromFunctionLiteral(Handle<SharedFunctionInfo> shared_info,
-                                      FunctionLiteral* lit);
+  // Add a new entry to the optimized code map for context-independent code.
+  static void AddSharedCodeToOptimizedCodeMap(Handle<SharedFunctionInfo> shared,
+                                              Handle<Code> code);
 
-  // Add a new entry to the optimized code map.
+  // Add a new entry to the optimized code map for context-dependent code.
   static void AddToOptimizedCodeMap(Handle<SharedFunctionInfo> shared,
                                     Handle<Context> native_context,
                                     Handle<Code> code,
@@ -6615,7 +6610,8 @@ class SharedFunctionInfo: public HeapObject {
 
   // Layout description of the optimized code map.
   static const int kNextMapIndex = 0;
-  static const int kEntriesStart = 1;
+  static const int kSharedCodeIndex = 1;
+  static const int kEntriesStart = 2;
   static const int kContextOffset = 0;
   static const int kCachedCodeOffset = 1;
   static const int kLiteralsOffset = 2;
@@ -6656,6 +6652,12 @@ class SharedFunctionInfo: public HeapObject {
   // available.
   DECL_ACCESSORS(feedback_vector, TypeFeedbackVector)
 
+  // Unconditionally clear the type feedback vector (including vector ICs).
+  void ClearTypeFeedbackInfo();
+
+  // Clear the type feedback vector with a more subtle policy at GC time.
+  void ClearTypeFeedbackInfoAtGCTime();
+
 #if TRACE_MAPS
   // [unique_id] - For --trace-maps purposes, an identifier that's persistent
   // even if the GC moves this SharedFunctionInfo.
@@ -6898,6 +6900,10 @@ class SharedFunctionInfo: public HeapObject {
 
   inline bool is_simple_parameter_list();
 
+  // Initialize a SharedFunctionInfo from a parsed function literal.
+  static void InitFromFunctionLiteral(Handle<SharedFunctionInfo> shared_info,
+                                      FunctionLiteral* lit);
+
   // Dispatched behavior.
   DECLARE_PRINTER(SharedFunctionInfo)
   DECLARE_VERIFIER(SharedFunctionInfo)

test/cctest/test-compiler.cc

@@ -370,7 +370,7 @@ TEST(FeedbackVectorUnaffectedByScopeChanges) {
 
 // Test that optimized code for different closures is actually shared
 // immediately by the FastNewClosureStub when run in the same context.
-TEST(OptimizedCodeSharing) {
+TEST(OptimizedCodeSharing1) {
   FLAG_stress_compaction = false;
   FLAG_allow_natives_syntax = true;
   FLAG_cache_optimized_code = true;
@@ -380,7 +380,8 @@ TEST(OptimizedCodeSharing) {
     LocalContext env;
     env->Global()->Set(v8::String::NewFromUtf8(CcTest::isolate(), "x"),
                        v8::Integer::New(CcTest::isolate(), i));
-    CompileRun("function MakeClosure() {"
+    CompileRun(
+        "function MakeClosure() {"
         "  return function() { return x; };"
         "}"
         "var closure0 = MakeClosure();"
@@ -400,6 +401,61 @@ TEST(OptimizedCodeSharing) {
 }
 
 
+// Test that optimized code for different closures is actually shared
+// immediately by the FastNewClosureStub when run different contexts.
+TEST(OptimizedCodeSharing2) {
+  if (FLAG_stress_compaction) return;
+  FLAG_allow_natives_syntax = true;
+  FLAG_cache_optimized_code = true;
+  FLAG_turbo_cache_shared_code = true;
+  const char* flag = "--turbo-filter=*";
+  FlagList::SetFlagsFromString(flag, StrLength(flag));
+  CcTest::InitializeVM();
+  v8::HandleScope scope(CcTest::isolate());
+  v8::Local<v8::Script> script = v8_compile(
+      "function MakeClosure() {"
+      "  return function() { return x; };"
+      "}");
+  Handle<Code> reference_code;
+  {
+    LocalContext env;
+    env->Global()->Set(v8::String::NewFromUtf8(CcTest::isolate(), "x"),
+                       v8::Integer::New(CcTest::isolate(), 23));
+    script->GetUnboundScript()->BindToCurrentContext()->Run();
+    CompileRun(
+        "var closure0 = MakeClosure();"
+        "%DebugPrint(closure0());"
+        "%OptimizeFunctionOnNextCall(closure0);"
+        "%DebugPrint(closure0());");
+    Handle<JSFunction> fun0 = v8::Utils::OpenHandle(
+        *v8::Local<v8::Function>::Cast(env->Global()->Get(v8_str("closure0"))));
+    CHECK(fun0->IsOptimized() || !CcTest::i_isolate()->use_crankshaft());
+    reference_code = handle(fun0->code());
+  }
+  for (int i = 0; i < 10; i++) {
+    LocalContext env;
+    env->Global()->Set(v8::String::NewFromUtf8(CcTest::isolate(), "x"),
+                       v8::Integer::New(CcTest::isolate(), i));
+    script->GetUnboundScript()->BindToCurrentContext()->Run();
+    CompileRun(
+        "var closure0 = MakeClosure();"
+        "%DebugPrint(closure0());"
+        "%OptimizeFunctionOnNextCall(closure0);"
+        "%DebugPrint(closure0());"
+        "var closure1 = MakeClosure();"
+        "var closure2 = MakeClosure();");
+    Handle<JSFunction> fun1 = v8::Utils::OpenHandle(
+        *v8::Local<v8::Function>::Cast(env->Global()->Get(v8_str("closure1"))));
+    Handle<JSFunction> fun2 = v8::Utils::OpenHandle(
+        *v8::Local<v8::Function>::Cast(env->Global()->Get(v8_str("closure2"))));
+    CHECK(fun1->IsOptimized() || !CcTest::i_isolate()->use_crankshaft());
+    CHECK(fun2->IsOptimized() || !CcTest::i_isolate()->use_crankshaft());
+    CHECK_EQ(*reference_code, fun1->code());
+    CHECK_EQ(*reference_code, fun2->code());
+  }
+}
+
+
 TEST(CompileFunctionInContext) {
   CcTest::InitializeVM();
   v8::HandleScope scope(CcTest::isolate());