Adding a type vector to replace type cells.

src/full-codegen.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 327 matching lines @@
   }
   unsigned table_offset = cgen.EmitBackEdgeTable();
 
   Code::Flags flags = Code::ComputeFlags(Code::FUNCTION);
   Handle<Code> code = CodeGenerator::MakeCodeEpilogue(&masm, flags, info);
   code->set_optimizable(info->IsOptimizable() &&
                         !info->function()->dont_optimize() &&
                         info->function()->scope()->AllowsLazyCompilation());
   cgen.PopulateDeoptimizationData(code);
   cgen.PopulateTypeFeedbackInfo(code);
-  cgen.PopulateTypeFeedbackCells(code);
   code->set_has_deoptimization_support(info->HasDeoptimizationSupport());
   code->set_handler_table(*cgen.handler_table());
 #ifdef ENABLE_DEBUGGER_SUPPORT
   code->set_compiled_optimizable(info->IsOptimizable());
 #endif  // ENABLE_DEBUGGER_SUPPORT
   code->set_allow_osr_at_loop_nesting_level(0);
   code->set_profiler_ticks(0);
   code->set_back_edge_table_offset(table_offset);
   code->set_back_edges_patched_for_osr(false);
   CodeGenerator::PrintCode(code, info);
@@ skipping 21 matching lines @@
   __ dd(length);
   for (unsigned i = 0; i < length; ++i) {
     __ dd(back_edges_[i].id.ToInt());
     __ dd(back_edges_[i].pc);
     __ dd(back_edges_[i].loop_depth);
   }
   return offset;
 }
 
 
+void FullCodeGenerator::FeedbackVectorWrapper::Initialize(
+    Isolate* isolate,
+    int minimum_length,
+    int maximum_length) {
+  ASSERT_EQ(isolate->heap()->the_hole_value(),
+            *TypeFeedbackInfo::UninitializedSentinel(isolate));
+  feedback_vector_ = isolate->factory()->NewFixedArrayWithHoles(minimum_length,

[Benedikt Meurer, 2014/01/24 11:29:54]

As discussed offline: Please add an explanation here, that we have to do this
for now because of our parser.

[mvstanton, 2014/01/30 15:13:41]

Changed to a new approach.

+                                                                TENURED);
+  maximum_length_ = maximum_length;
+  used_ = 0;
+}
+
+
+void FullCodeGenerator::FeedbackVectorWrapper::Visit(
+    Isolate* isolate,
+    AstNode* node) {
+  int new_used = node->ConsumeFeedbackSlots(isolate, used_);
+  if (new_used > used_) {
+    int old_vector_length = feedback_vector_->length();
+    if (new_used > old_vector_length) {
+      int min_extra = new_used - old_vector_length;
+      int max_extra = maximum_length_ - old_vector_length;
+      int extra = Min(min_extra * 4, max_extra);
+
+      if (FLAG_trace_type_feedback) {
+        PrintF("Growing vector (min, max, chosen) (%d, %d, %d)\n",
+               min_extra, max_extra, extra);
+      }
+
+      // We must grow the vector, somewhere between [new_used, maximum_length_].
+      Handle<FixedArray> new_array = isolate->factory()->CopySizeFixedArray(
+          feedback_vector_,
+          feedback_vector_->length() + extra,
+          TENURED);
+      *(feedback_vector_.location()) = *new_array;
+
+      // Initialize the slots to undefined
+      for (int i = Max(0, old_vector_length - 1);
+           i < feedback_vector_->length();
+           i++) {
+        feedback_vector_->set(
+            i,
+            *TypeFeedbackInfo::UninitializedSentinel(isolate),
+            SKIP_WRITE_BARRIER);
+      }
+    }
+
+    used_ = new_used;
+    ASSERT(used_ <= feedback_vector_->length());
+  }
+}
+
+
+void FullCodeGenerator::FeedbackVectorWrapper::Set(
+    int slot,
+    Handle<Object> object) {
+  ASSERT(feedback_vector_->length() > slot);
+  feedback_vector_->set(slot, *object);
+}
+
+
+void FullCodeGenerator::FeedbackVectorWrapper::Finalize(Isolate* isolate) {
+  ASSERT(used_ <= feedback_vector_->length());
+  if (used_ < feedback_vector_->length()) {
+    if (FLAG_trace_type_feedback) {
+      PrintF("Allocated feedback vector: shrank %d to %d slots.\n",
+             feedback_vector_->length(), used_);
+    }
+
+    if (used_ > 0) {
+      feedback_vector_->Shrink(used_);
+    }
+  }
+}
+
+
 void FullCodeGenerator::PopulateDeoptimizationData(Handle<Code> code) {
   // Fill in the deoptimization information.
   ASSERT(info_->HasDeoptimizationSupport() || bailout_entries_.is_empty());
   if (!info_->HasDeoptimizationSupport()) return;
   int length = bailout_entries_.length();
   Handle<DeoptimizationOutputData> data = isolate()->factory()->
       NewDeoptimizationOutputData(length, TENURED);
   for (int i = 0; i < length; i++) {
     data->SetAstId(i, bailout_entries_[i].id);
     data->SetPcAndState(i, Smi::FromInt(bailout_entries_[i].pc_and_state));
   }
   code->set_deoptimization_data(*data);
 }
 
 
 void FullCodeGenerator::PopulateTypeFeedbackInfo(Handle<Code> code) {
   Handle<TypeFeedbackInfo> info = isolate()->factory()->NewTypeFeedbackInfo();
   info->set_ic_total_count(ic_total_count_);
+  info->set_feedback_vector(*FeedbackVector());
   ASSERT(!isolate()->heap()->InNewSpace(*info));
   code->set_type_feedback_info(*info);
 }
 
 
 void FullCodeGenerator::Initialize() {
   // The generation of debug code must match between the snapshot code and the
   // code that is generated later.  This is assumed by the debugger when it is
   // calculating PC offsets after generating a debug version of code.  Therefore
   // we disable the production of debug code in the full compiler if we are
   // either generating a snapshot or we booted from a snapshot.
   generate_debug_code_ = FLAG_debug_code &&
                          !Serializer::enabled() &&
                          !Snapshot::HaveASnapshotToStartFrom();
   masm_->set_emit_debug_code(generate_debug_code_);
   masm_->set_predictable_code_size(true);
   InitializeAstVisitor(info_->zone());
 }
 
 
-void FullCodeGenerator::PopulateTypeFeedbackCells(Handle<Code> code) {
-  if (type_feedback_cells_.is_empty()) return;
-  int length = type_feedback_cells_.length();
-  int array_size = TypeFeedbackCells::LengthOfFixedArray(length);
-  Handle<TypeFeedbackCells> cache = Handle<TypeFeedbackCells>::cast(
-      isolate()->factory()->NewFixedArray(array_size, TENURED));
-  for (int i = 0; i < length; i++) {
-    cache->SetAstId(i, type_feedback_cells_[i].ast_id);
-    cache->SetCell(i, *type_feedback_cells_[i].cell);
-  }
-  TypeFeedbackInfo::cast(code->type_feedback_info())->set_type_feedback_cells(
-      *cache);
-}
-
-
 void FullCodeGenerator::PrepareForBailout(Expression* node, State state) {
   PrepareForBailoutForId(node->id(), state);
 }
 
 
 void FullCodeGenerator::CallLoadIC(ContextualMode mode, TypeFeedbackId id) {
   Handle<Code> ic = LoadIC::initialize_stub(isolate(), mode);
   CallIC(ic, mode, id);
 }
 
@@ skipping 28 matching lines @@
   unsigned pc_and_state =
       StateField::encode(state) | PcField::encode(masm_->pc_offset());
   ASSERT(Smi::IsValid(pc_and_state));
   BailoutEntry entry = { id, pc_and_state };
   ASSERT(!prepared_bailout_ids_.Contains(id.ToInt()));
   prepared_bailout_ids_.Add(id.ToInt(), zone());
   bailout_entries_.Add(entry, zone());
 }
 
 
-void FullCodeGenerator::RecordTypeFeedbackCell(
-    TypeFeedbackId id, Handle<Cell> cell) {
-  TypeFeedbackCellEntry entry = { id, cell };
-  type_feedback_cells_.Add(entry, zone());
-}
-
-
 void FullCodeGenerator::RecordBackEdge(BailoutId ast_id) {
   // The pc offset does not need to be encoded and packed together with a state.
   ASSERT(masm_->pc_offset() > 0);
   ASSERT(loop_depth() > 0);
   uint8_t depth = Min(loop_depth(), Code::kMaxLoopNestingMarker);
   BackEdgeEntry entry =
       { ast_id, static_cast<unsigned>(masm_->pc_offset()), depth };
   back_edges_.Add(entry, zone());
 }
 
@@ skipping 1238 matching lines @@
   }
   return true;
 }
 #endif  // DEBUG
 
 
 #undef __
 
 
 } }  // namespace v8::internal