[iterpreter] Share feedback slots for global stores to the same variable.

Bug: v8:7206, chromium:576312
Change-Id: I1628e7966a40fa7d6f628bd972b0ad0142a5d349
Reviewed-on: https://chromium-review.googlesource.com/970825
Reviewed-by: Mythri Alle <mythria@google.com>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52075}

src/interpreter/bytecode-generator.cc

@@ -804,39 +804,40 @@ class BytecodeGenerator::CurrentScope final {
 
 class BytecodeGenerator::FeedbackSlotCache : public ZoneObject {
  public:
-  typedef std::pair<TypeofMode, void*> Key;
-
   explicit FeedbackSlotCache(Zone* zone) : map_(zone) {}
 
-  void Put(TypeofMode typeof_mode, Variable* variable, FeedbackSlot slot) {
-    Key key = std::make_pair(typeof_mode, variable);
-    auto entry = std::make_pair(key, slot);
-    map_.insert(entry);
+  void Put(FeedbackSlotKind slot_kind, Variable* variable, FeedbackSlot slot) {
+    PutImpl(slot_kind, variable, slot);
   }
-  void Put(AstNode* node, FeedbackSlot slot) {
-    Key key = std::make_pair(NOT_INSIDE_TYPEOF, node);
-    auto entry = std::make_pair(key, slot);
-    map_.insert(entry);
+  void Put(FeedbackSlotKind slot_kind, AstNode* node, FeedbackSlot slot) {
+    PutImpl(slot_kind, node, slot);
   }
 
-  FeedbackSlot Get(TypeofMode typeof_mode, Variable* variable) const {
-    Key key = std::make_pair(typeof_mode, variable);
-    auto iter = map_.find(key);
-    if (iter != map_.end()) {
-      return iter->second;
-    }
-    return FeedbackSlot();
+  FeedbackSlot Get(FeedbackSlotKind slot_kind, Variable* variable) const {
+    return GetImpl(slot_kind, variable);
   }
-  FeedbackSlot Get(AstNode* node) const {
-    Key key = std::make_pair(NOT_INSIDE_TYPEOF, node);
-    auto iter = map_.find(key);
-    if (iter != map_.end()) {
-      return iter->second;
-    }
-    return FeedbackSlot();
+  FeedbackSlot Get(FeedbackSlotKind slot_kind, AstNode* node) const {
+    return GetImpl(slot_kind, node);
   }
 
  private:
+  typedef std::pair<FeedbackSlotKind, void*> Key;
+
+  void PutImpl(FeedbackSlotKind slot_kind, void* node, FeedbackSlot slot) {
+    Key key = std::make_pair(slot_kind, node);
+    auto entry = std::make_pair(key, slot);
+    map_.insert(entry);
+  }
+
+  FeedbackSlot GetImpl(FeedbackSlotKind slot_kind, void* node) const {
+    Key key = std::make_pair(slot_kind, node);
+    auto iter = map_.find(key);
+    if (iter != map_.end()) {
+      return iter->second;
+    }
+    return FeedbackSlot();
+  }
+
   ZoneMap<Key, FeedbackSlot> map_;
 };
 
@@ -2658,9 +2659,7 @@ void BytecodeGenerator::BuildVariableAssignment(
       break;
     }
     case VariableLocation::UNALLOCATED: {
-      // TODO(ishell): consider using FeedbackSlotCache for variables here.
-      FeedbackSlot slot =
-          feedback_spec()->AddStoreGlobalICSlot(language_mode());
+      FeedbackSlot slot = GetCachedStoreGlobalICSlot(language_mode(), variable);
       builder()->StoreGlobal(variable->raw_name(), feedback_index(slot));
       break;
     }
@@ -4963,23 +4962,42 @@ int BytecodeGenerator::feedback_index(FeedbackSlot slot) const {
 
 FeedbackSlot BytecodeGenerator::GetCachedLoadGlobalICSlot(
     TypeofMode typeof_mode, Variable* variable) {
-  FeedbackSlot slot = feedback_slot_cache()->Get(typeof_mode, variable);
+  FeedbackSlotKind slot_kind =
+      typeof_mode == INSIDE_TYPEOF
+          ? FeedbackSlotKind::kLoadGlobalInsideTypeof
+          : FeedbackSlotKind::kLoadGlobalNotInsideTypeof;
+  FeedbackSlot slot = feedback_slot_cache()->Get(slot_kind, variable);
   if (!slot.IsInvalid()) {
     return slot;
   }
   slot = feedback_spec()->AddLoadGlobalICSlot(typeof_mode);
-  feedback_slot_cache()->Put(typeof_mode, variable, slot);
+  feedback_slot_cache()->Put(slot_kind, variable, slot);
+  return slot;
+}
+
+FeedbackSlot BytecodeGenerator::GetCachedStoreGlobalICSlot(
+    LanguageMode language_mode, Variable* variable) {
+  FeedbackSlotKind slot_kind = is_strict(language_mode)
+                                   ? FeedbackSlotKind::kStoreGlobalStrict
+                                   : FeedbackSlotKind::kStoreGlobalSloppy;
+  FeedbackSlot slot = feedback_slot_cache()->Get(slot_kind, variable);
+  if (!slot.IsInvalid()) {
+    return slot;
+  }
+  slot = feedback_spec()->AddStoreGlobalICSlot(language_mode);
+  feedback_slot_cache()->Put(slot_kind, variable, slot);
   return slot;
 }
 
 FeedbackSlot BytecodeGenerator::GetCachedCreateClosureSlot(
     FunctionLiteral* literal) {
-  FeedbackSlot slot = feedback_slot_cache()->Get(literal);
+  FeedbackSlotKind slot_kind = FeedbackSlotKind::kCreateClosure;
+  FeedbackSlot slot = feedback_slot_cache()->Get(slot_kind, literal);
   if (!slot.IsInvalid()) {
     return slot;
   }
   slot = feedback_spec()->AddCreateClosureSlot();
-  feedback_slot_cache()->Put(literal, slot);
+  feedback_slot_cache()->Put(slot_kind, literal, slot);
   return slot;
 }
 

src/interpreter/bytecode-generator.h

@@ -262,6 +262,8 @@ class BytecodeGenerator final : public AstVisitor<BytecodeGenerator> {
   // already exists.
   FeedbackSlot GetCachedLoadGlobalICSlot(TypeofMode typeof_mode,
                                          Variable* variable);
+  FeedbackSlot GetCachedStoreGlobalICSlot(LanguageMode language_mode,
+                                          Variable* variable);
   FeedbackSlot GetCachedCreateClosureSlot(FunctionLiteral* literal);
 
   void AddToEagerLiteralsIfEager(FunctionLiteral* literal);

test/cctest/interpreter/bytecode_expectations/DeclareGlobals.golden

@@ -76,7 +76,7 @@ bytecodes: [
   /*    8 S> */ B(LdaSmi), I8(1),
   /*    8 E> */ B(StaGlobal), U8(1), U8(2),
   /*   11 S> */ B(LdaSmi), I8(2),
-  /*   12 E> */ B(StaGlobal), U8(1), U8(4),
+  /*   12 E> */ B(StaGlobal), U8(1), U8(2),
                 B(Star), R(0),
   /*   15 S> */ B(Return),
 ]

test/cctest/test-feedback-vector.cc

@@ -495,11 +495,10 @@ TEST(ReferenceContextAllocatesNoSlots) {
     Handle<FeedbackVector> feedback_vector =
         handle(f->feedback_vector(), isolate);
     FeedbackVectorHelper helper(feedback_vector);
-    CHECK_EQ(4, helper.slot_count());
+    CHECK_EQ(3, helper.slot_count());
     CHECK_SLOT_KIND(helper, 0, FeedbackSlotKind::kStoreGlobalSloppy);
     CHECK_SLOT_KIND(helper, 1, FeedbackSlotKind::kLoadGlobalNotInsideTypeof);
-    CHECK_SLOT_KIND(helper, 2, FeedbackSlotKind::kStoreGlobalSloppy);
-    CHECK_SLOT_KIND(helper, 3, FeedbackSlotKind::kLoadGlobalNotInsideTypeof);
+    CHECK_SLOT_KIND(helper, 2, FeedbackSlotKind::kLoadGlobalNotInsideTypeof);
   }
 
   {

test/cctest/test-serialize.cc

@@ -1460,7 +1460,7 @@ TEST(CodeSerializerLargeCodeObjectWithIncrementalMarking) {
   Vector<const uint8_t> source = ConstructSource(
       STATIC_CHAR_VECTOR("var j=1; if (j == 0) {"),
       STATIC_CHAR_VECTOR("for (var i = 0; i < Object.prototype; i++);"),
-      STATIC_CHAR_VECTOR("} j=7; var s = 'happy_hippo'; j"), 10000);
+      STATIC_CHAR_VECTOR("} j=7; var s = 'happy_hippo'; j"), 20000);
   Handle<String> source_str =
       isolate->factory()->NewStringFromOneByte(source).ToHandleChecked();