Share literals arrays per <NativeContext, SharedFunctionInfo> pair.

src/objects.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/objects.h"
 
 #include <cmath>
 #include <iomanip>
 #include <sstream>
 
@@ skipping 10125 matching lines @@
 }
 
 
 void SharedFunctionInfo::AddToOptimizedCodeMap(
     Handle<SharedFunctionInfo> shared,
     Handle<Context> native_context,
     Handle<Code> 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.is_null() ||
+         !shared->SearchOptimizedCodeMap(*native_context, osr_ast_id).code);
+  DCHECK(code.is_null() || 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;
   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;
   } else {
+    Handle<FixedArray> old_code_map = Handle<FixedArray>::cast(value);
+    int entry =
+        shared->SearchOptimizedCodeMapEntry(*native_context, osr_ast_id);
+    if (entry > kSharedCodeIndex) {
+      // Found an existing context-specific entry, it must not contain any code.
+      DCHECK(old_code_map->get(entry + kCachedCodeOffset) == nullptr);
+      // Just set the code and literals to the entry.
+      if (!code.is_null()) {
+        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.
-    Handle<FixedArray> old_code_map = Handle<FixedArray>::cast(value);
     new_code_map = isolate->factory()->CopyFixedArrayAndGrow(
         old_code_map, kEntryLength, TENURED);
     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);
   }
   new_code_map->set(old_length + kContextOffset, *native_context);
-  new_code_map->set(old_length + kCachedCodeOffset, *code);
+  new_code_map->set(old_length + kCachedCodeOffset,
+                    code.is_null() ? nullptr : *code);
   new_code_map->set(old_length + kLiteralsOffset, *literals);
   new_code_map->set(old_length + 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 != nullptr) {
+      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());
   }
 #endif
   shared->set_optimized_code_map(*new_code_map);
 }
 
 
 void SharedFunctionInfo::ClearOptimizedCodeMap() {
   FixedArray* code_map = FixedArray::cast(optimized_code_map());
@@ skipping 13 matching lines @@
 void SharedFunctionInfo::EvictFromOptimizedCodeMap(Code* optimized_code,
                                                    const char* reason) {
   DisallowHeapAllocation no_gc;
   if (optimized_code_map()->IsSmi()) return;
 
   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(src + kCachedCodeOffset, static_cast<Code*>(nullptr));
     }
+
+    // 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.
     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");
     }
   }
@@ skipping 1008 matching lines @@
         opt_count() >= FLAG_max_opt_count) {
       // Re-enable optimizations if they were disabled due to opt_count limit.
       set_optimization_disabled(false);
     }
     set_opt_count(0);
     set_deopt_count(0);
   }
 }
 
 
-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();
   if (!value->IsSmi()) {
     FixedArray* optimized_code_map = FixedArray::cast(value);
     int length = optimized_code_map->length();
     Smi* osr_ast_id_smi = Smi::FromInt(osr_ast_id.ToInt());
     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) {

[Michael Starzinger, 2015/09/22 10:57:34]

This tracing will also be printed when adding new entries to the optimized code
map. This will turn out to be misleading.

[Igor Sheludko, 2015/09/22 12:58:11]

Fixed.

       PrintF("[didn't find optimized code in optimized code map for ");
       ShortPrint();
       PrintF("]\n");
     }
   }
-  return {nullptr, nullptr};
+  return -1;
 }
 
 
+CodeAndLiterals SharedFunctionInfo::SearchOptimizedCodeMap(
+    Context* native_context, BailoutId osr_ast_id) {
+  int entry = SearchOptimizedCodeMapEntry(native_context, osr_ast_id);
+  if (entry == kNotFound) return {nullptr, nullptr};
+
+  FixedArray* code_map = FixedArray::cast(optimized_code_map());
+  if (entry == kSharedCodeIndex) {
+    return {Code::cast(code_map->get(kSharedCodeIndex)), nullptr};
+  }
+  DCHECK_LE(entry + kEntryLength, code_map->length());
+  Object* code = code_map->get(entry + kCachedCodeOffset);
+  return {code == nullptr ? nullptr : Code::cast(code),
+          FixedArray::cast(code_map->get(entry + kLiteralsOffset))};
+}
+
+
 #define DECLARE_TAG(ignore1, name, ignore2) name,
 const char* const VisitorSynchronization::kTags[
     VisitorSynchronization::kNumberOfSyncTags] = {
   VISITOR_SYNCHRONIZATION_TAGS_LIST(DECLARE_TAG)
 };
 #undef DECLARE_TAG
 
 
 #define DECLARE_TAG(ignore1, ignore2, name) name,
 const char* const VisitorSynchronization::kTagNames[
@@ skipping 5382 matching lines @@
   if (cell->value() != *new_value) {
     cell->set_value(*new_value);
     Isolate* isolate = cell->GetIsolate();
     cell->dependent_code()->DeoptimizeDependentCodeGroup(
         isolate, DependentCode::kPropertyCellChangedGroup);
   }
 }
 
 }  // namespace internal
 }  // namespace v8