Share literals arrays per <NativeContext, SharedFunctionInfo> pair.

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 7db54aa811e7ce2ed260f4ec729675231fd830bd..1262b521a7d5dc8b9515d489db077e0315f799ca 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -10137,47 +10137,60 @@ void SharedFunctionInfo::AddSharedCodeToOptimizedCodeMap(
 
 
 void SharedFunctionInfo::AddToOptimizedCodeMap(
-    Handle<SharedFunctionInfo> shared,
-    Handle<Context> native_context,
-    Handle<Code> code,
-    Handle<FixedArray> literals,
+    Handle<SharedFunctionInfo> shared, Handle<Context> native_context,
+    Handle<HeapObject> code, Handle<FixedArray> literals,
     BailoutId osr_ast_id) {
   Isolate* isolate = shared->GetIsolate();
-  DCHECK(!shared->SearchOptimizedCodeMap(*native_context, osr_ast_id).code);
-  DCHECK(code->kind() == Code::OPTIMIZED_FUNCTION);
+  DCHECK(*code == isolate->heap()->undefined_value() ||
+         !shared->SearchOptimizedCodeMap(*native_context, osr_ast_id).code);
+  DCHECK(*code == isolate->heap()->undefined_value() ||
+         Code::cast(*code)->kind() == Code::OPTIMIZED_FUNCTION);
   DCHECK(native_context->IsNativeContext());
   STATIC_ASSERT(kEntryLength == 4);
   Handle<FixedArray> new_code_map;
   Handle<Object> value(shared->optimized_code_map(), isolate);
-  int old_length;
+  int entry;
   if (value->IsSmi()) {
     // No optimized code map.
     DCHECK_EQ(0, Smi::cast(*value)->value());
     new_code_map = isolate->factory()->NewFixedArray(kInitialLength, TENURED);
-    old_length = kEntriesStart;
+    entry = kEntriesStart;
   } else {
-    // Copy old optimized code map and append one new entry.
     Handle<FixedArray> old_code_map = Handle<FixedArray>::cast(value);
+    entry = shared->SearchOptimizedCodeMapEntry(*native_context, osr_ast_id);
+    if (entry > kSharedCodeIndex) {
+      // Found an existing context-specific entry, it must not contain any code.
+      DCHECK_EQ(isolate->heap()->undefined_value(),
+                old_code_map->get(entry + kCachedCodeOffset));
+      // Just set the code and literals to the entry.
+      old_code_map->set(entry + kCachedCodeOffset, *code);
+      old_code_map->set(entry + kLiteralsOffset, *literals);
+      return;
+    }
+
+    // Copy old optimized code map and append one new entry.
     new_code_map = isolate->factory()->CopyFixedArrayAndGrow(
         old_code_map, kEntryLength, TENURED);
-    old_length = old_code_map->length();
+    int old_length = old_code_map->length();
     // Zap the old map to avoid any stale entries. Note that this is required
     // for correctness because entries are being treated weakly by the GC.
     MemsetPointer(old_code_map->data_start(), isolate->heap()->the_hole_value(),
                   old_length);
+    entry = old_length;
   }
-  new_code_map->set(old_length + kContextOffset, *native_context);
-  new_code_map->set(old_length + kCachedCodeOffset, *code);
-  new_code_map->set(old_length + kLiteralsOffset, *literals);
-  new_code_map->set(old_length + kOsrAstIdOffset,
-                    Smi::FromInt(osr_ast_id.ToInt()));
+  new_code_map->set(entry + kContextOffset, *native_context);
+  new_code_map->set(entry + kCachedCodeOffset, *code);
+  new_code_map->set(entry + kLiteralsOffset, *literals);
+  new_code_map->set(entry + kOsrAstIdOffset, Smi::FromInt(osr_ast_id.ToInt()));
 
 #ifdef DEBUG
   for (int i = kEntriesStart; i < new_code_map->length(); i += kEntryLength) {
     DCHECK(new_code_map->get(i + kContextOffset)->IsNativeContext());
-    DCHECK(new_code_map->get(i + kCachedCodeOffset)->IsCode());
-    DCHECK(Code::cast(new_code_map->get(i + kCachedCodeOffset))->kind() ==
-           Code::OPTIMIZED_FUNCTION);
+    Object* code = new_code_map->get(i + kCachedCodeOffset);
+    if (code != isolate->heap()->undefined_value()) {
+      DCHECK(code->IsCode());
+      DCHECK(Code::cast(code)->kind() == Code::OPTIMIZED_FUNCTION);
+    }
     DCHECK(new_code_map->get(i + kLiteralsOffset)->IsFixedArray());
     DCHECK(new_code_map->get(i + kOsrAstIdOffset)->IsSmi());
   }
@@ -10206,37 +10219,43 @@ void SharedFunctionInfo::EvictFromOptimizedCodeMap(Code* optimized_code,
   DisallowHeapAllocation no_gc;
   if (optimized_code_map()->IsSmi()) return;
 
+  Heap* heap = GetHeap();
   FixedArray* code_map = FixedArray::cast(optimized_code_map());
   int dst = kEntriesStart;
   int length = code_map->length();
   for (int src = kEntriesStart; src < length; src += kEntryLength) {
     DCHECK(code_map->get(src)->IsNativeContext());
-    if (Code::cast(code_map->get(src + kCachedCodeOffset)) == optimized_code) {
-      // Evict the src entry by not copying it to the dst entry.
+    if (code_map->get(src + kCachedCodeOffset) == optimized_code) {
+      BailoutId osr(Smi::cast(code_map->get(src + kOsrAstIdOffset))->value());
       if (FLAG_trace_opt) {
         PrintF("[evicting entry from optimizing code map (%s) for ", reason);
         ShortPrint();
-        BailoutId osr(Smi::cast(code_map->get(src + kOsrAstIdOffset))->value());
         if (osr.IsNone()) {
           PrintF("]\n");
         } else {
           PrintF(" (osr ast id %d)]\n", osr.ToInt());
         }
       }
-    } else {
-      // Keep the src entry by copying it to the dst entry.
-      if (dst != src) {
-        code_map->set(dst + kContextOffset,
-                      code_map->get(src + kContextOffset));
-        code_map->set(dst + kCachedCodeOffset,
-                      code_map->get(src + kCachedCodeOffset));
-        code_map->set(dst + kLiteralsOffset,
-                      code_map->get(src + kLiteralsOffset));
-        code_map->set(dst + kOsrAstIdOffset,
-                      code_map->get(src + kOsrAstIdOffset));
+      if (!osr.IsNone()) {
+        // Evict the src entry by not copying it to the dst entry.
+        continue;
       }
-      dst += kEntryLength;
+      // In case of non-OSR entry just clear the code in order to proceed
+      // sharing literals.
+      code_map->set_undefined(src + kCachedCodeOffset);
+    }
+
+    // Keep the src entry by copying it to the dst entry.
+    if (dst != src) {
+      code_map->set(dst + kContextOffset, code_map->get(src + kContextOffset));
+      code_map->set(dst + kCachedCodeOffset,
+                    code_map->get(src + kCachedCodeOffset));
+      code_map->set(dst + kLiteralsOffset,
+                    code_map->get(src + kLiteralsOffset));
+      code_map->set(dst + kOsrAstIdOffset,
+                    code_map->get(src + kOsrAstIdOffset));
     }
+    dst += kEntryLength;
   }
   if (code_map->get(kSharedCodeIndex) == optimized_code) {
     // Evict context-independent code as well.
@@ -10249,8 +10268,8 @@ void SharedFunctionInfo::EvictFromOptimizedCodeMap(Code* optimized_code,
   }
   if (dst != length) {
     // Always trim even when array is cleared because of heap verifier.
-    GetHeap()->RightTrimFixedArray<Heap::CONCURRENT_TO_SWEEPER>(code_map,
-                                                                length - dst);
+    heap->RightTrimFixedArray<Heap::CONCURRENT_TO_SWEEPER>(code_map,
+                                                           length - dst);
     if (code_map->length() == kEntriesStart &&
         code_map->get(kSharedCodeIndex)->IsUndefined()) {
       ClearOptimizedCodeMap();
@@ -11265,8 +11284,8 @@ void SharedFunctionInfo::ResetForNewContext(int new_ic_age) {
 }
 
 
-CodeAndLiterals SharedFunctionInfo::SearchOptimizedCodeMap(
-    Context* native_context, BailoutId osr_ast_id) {
+int SharedFunctionInfo::SearchOptimizedCodeMapEntry(Context* native_context,
+                                                    BailoutId osr_ast_id) {
   DisallowHeapAllocation no_gc;
   DCHECK(native_context->IsNativeContext());
   Object* value = optimized_code_map();
@@ -11277,21 +11296,41 @@ CodeAndLiterals SharedFunctionInfo::SearchOptimizedCodeMap(
     for (int i = kEntriesStart; i < length; i += kEntryLength) {
       if (optimized_code_map->get(i + kContextOffset) == native_context &&
           optimized_code_map->get(i + kOsrAstIdOffset) == osr_ast_id_smi) {
-        return {Code::cast(optimized_code_map->get(i + kCachedCodeOffset)),
-                FixedArray::cast(optimized_code_map->get(i + kLiteralsOffset))};
+        return i;
       }
     }
     Object* shared_code = optimized_code_map->get(kSharedCodeIndex);
     if (shared_code->IsCode() && osr_ast_id.IsNone()) {
-      return {Code::cast(shared_code), nullptr};
+      return kSharedCodeIndex;
     }
-    if (FLAG_trace_opt) {
-      PrintF("[didn't find optimized code in optimized code map for ");
-      ShortPrint();
-      PrintF("]\n");
+  }
+  return -1;
+}
+
+
+CodeAndLiterals SharedFunctionInfo::SearchOptimizedCodeMap(
+    Context* native_context, BailoutId osr_ast_id) {
+  CodeAndLiterals result = {nullptr, nullptr};
+  int entry = SearchOptimizedCodeMapEntry(native_context, osr_ast_id);
+  if (entry != kNotFound) {
+    FixedArray* code_map = FixedArray::cast(optimized_code_map());
+    if (entry == kSharedCodeIndex) {
+      result = {Code::cast(code_map->get(kSharedCodeIndex)), nullptr};
+
+    } else {
+      DCHECK_LE(entry + kEntryLength, code_map->length());
+      Object* code = code_map->get(entry + kCachedCodeOffset);
+      result = {code->IsUndefined() ? nullptr : Code::cast(code),
+                FixedArray::cast(code_map->get(entry + kLiteralsOffset))};
     }
   }
-  return {nullptr, nullptr};
+  if (FLAG_trace_opt && !optimized_code_map()->IsSmi() &&
+      result.code == nullptr) {
+    PrintF("[didn't find optimized code in optimized code map for ");
+    ShortPrint();
+    PrintF("]\n");
+  }
+  return result;
 }