[ast] Remove heap accesses from AST numbering

src/interpreter/bytecode-generator.cc

 // Copyright 2015 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/interpreter/bytecode-generator.h"
 
 #include "src/ast/compile-time-value.h"
 #include "src/ast/scopes.h"
 #include "src/builtins/builtins-constructor.h"
 #include "src/code-stubs.h"
@@ skipping 559 matching lines @@
           info->isolate(), info->zone(), info->num_parameters_including_this(),
           info->scope()->MaxNestedContextChainLength(),
           info->scope()->num_stack_slots(), info->literal(),
           info->SourcePositionRecordingMode())),
       info_(info),
       scope_(info->scope()),
       globals_builder_(new (zone()) GlobalDeclarationsBuilder(info->zone())),
       global_declarations_(0, info->zone()),
       function_literals_(0, info->zone()),
       native_function_literals_(0, info->zone()),
+      object_literals_(0, info->zone()),
+      array_literals_(0, info->zone()),
       execution_control_(nullptr),
       execution_context_(nullptr),
       execution_result_(nullptr),
       generator_resume_points_(info->literal()->yield_count(), info->zone()),
       generator_state_(),
       loop_depth_(0),
       home_object_symbol_(info->isolate()->factory()->home_object_symbol()),
       iterator_symbol_(info->isolate()->factory()->iterator_symbol()),
       empty_fixed_array_(info->isolate()->factory()->empty_fixed_array()) {
   AstValueFactory* ast_value_factory = info->parse_info()->ast_value_factory();
   const AstRawString* prototype_string = ast_value_factory->prototype_string();
   ast_value_factory->Internalize(info->isolate());
   prototype_string_ = prototype_string->string();
   undefined_string_ = ast_value_factory->undefined_string();
 }
 
 Handle<BytecodeArray> BytecodeGenerator::FinalizeBytecode(Isolate* isolate) {
-  AllocateDeferredConstants();
+  AllocateDeferredConstants(isolate);
   if (HasStackOverflow()) return Handle<BytecodeArray>();
   return builder()->ToBytecodeArray(isolate);
 }
 
-void BytecodeGenerator::AllocateDeferredConstants() {
+void BytecodeGenerator::AllocateDeferredConstants(Isolate* isolate) {
   // Build global declaration pair arrays.
   for (GlobalDeclarationsBuilder* globals_builder : global_declarations_) {
     Handle<FixedArray> declarations =
         globals_builder->AllocateDeclarations(info());
     if (declarations.is_null()) return SetStackOverflow();
     builder()->InsertConstantPoolEntryAt(globals_builder->constant_pool_entry(),
                                          declarations);
   }
 
   // Find or build shared function infos.
   for (std::pair<FunctionLiteral*, size_t> literal : function_literals_) {
     FunctionLiteral* expr = literal.first;
     Handle<SharedFunctionInfo> shared_info =
         Compiler::GetSharedFunctionInfo(expr, info()->script(), info());
     if (shared_info.is_null()) return SetStackOverflow();
     builder()->InsertConstantPoolEntryAt(literal.second, shared_info);
   }
 
   // Find or build shared function infos for the native function templates.
   for (std::pair<NativeFunctionLiteral*, size_t> literal :
        native_function_literals_) {
     NativeFunctionLiteral* expr = literal.first;
     Handle<SharedFunctionInfo> shared_info =
         Compiler::GetSharedFunctionInfoForNative(expr->extension(),
                                                  expr->name());
     if (shared_info.is_null()) return SetStackOverflow();
     builder()->InsertConstantPoolEntryAt(literal.second, shared_info);
   }
+
+  // Build object literal constant properties
+  for (std::pair<ObjectLiteral*, size_t> literal : object_literals_) {
+    ObjectLiteral* object_literal = literal.first;
+    if (object_literal->properties_count() > 0) {
+      // If constant properties is an empty fixed array, we've already added it
+      // to the constant pool when visiting the object literal.
+      Handle<FixedArray> constant_properties =
+          object_literal->GetOrBuildConstantProperties(isolate);
+
+      builder()->InsertConstantPoolEntryAt(literal.second, constant_properties);
+    }
+  }

[rmcilroy, 2017/01/13 09:53:57]

nit - newline

[Leszek Swirski, 2017/01/13 10:58:10]

Done.

+  // Build array literal constant elements
+  for (std::pair<ArrayLiteral*, size_t> literal : array_literals_) {
+    ArrayLiteral* array_literal = literal.first;
+    Handle<ConstantElementsPair> constant_elements =
+        array_literal->GetOrBuildConstantElements(isolate);
+    builder()->InsertConstantPoolEntryAt(literal.second, constant_elements);
+  }
 }
 
 void BytecodeGenerator::GenerateBytecode(uintptr_t stack_limit) {
   DisallowHeapAllocation no_allocation;
   DisallowHandleAllocation no_handles;
   DisallowHandleDereference no_deref;
 
   InitializeAstVisitor(stack_limit);
 
   // Initialize the incoming context.
@@ skipping 963 matching lines @@
                                  expr->flags());
 }
 
 void BytecodeGenerator::VisitObjectLiteral(ObjectLiteral* expr) {
   // Deep-copy the literal boilerplate.
   uint8_t flags = CreateObjectLiteralFlags::Encode(
       expr->IsFastCloningSupported(),
       ConstructorBuiltinsAssembler::FastCloneShallowObjectPropertiesCount(
           expr->properties_count()),
       expr->ComputeFlags());
-  // If constant properties is an empty fixed array, use our cached
-  // empty_fixed_array to ensure it's only added to the constant pool once.
-  Handle<FixedArray> constant_properties = expr->properties_count() == 0
-                                               ? empty_fixed_array()
-                                               : expr->constant_properties();
+
   Register literal = register_allocator()->NewRegister();
-  builder()->CreateObjectLiteral(constant_properties, expr->literal_index(),
-                                 flags, literal);
+  size_t entry;
+  if (expr->properties_count() == 0) {
+    entry = builder()->GetConstantPoolEntry(empty_fixed_array());
+  } else {
+    entry = builder()->AllocateConstantPoolEntry();
+    object_literals_.push_back(std::make_pair(expr, entry));
+  }
+  builder()->CreateObjectLiteral(entry, expr->literal_index(), flags, literal);
 
   // Store computed values into the literal.
   int property_index = 0;
   AccessorTable accessor_table(zone());
   for (; property_index < expr->properties()->length(); property_index++) {
     ObjectLiteral::Property* property = expr->properties()->at(property_index);
     if (property->is_computed_name()) break;
     if (property->IsCompileTimeValue()) continue;
 
     RegisterAllocationScope inner_register_scope(this);
@@ skipping 161 matching lines @@
     }
   }
 
   builder()->LoadAccumulatorWithRegister(literal);
 }
 
 void BytecodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
   // Deep-copy the literal boilerplate.
   uint8_t flags = CreateArrayLiteralFlags::Encode(
       expr->IsFastCloningSupported(), expr->ComputeFlags());
-  builder()->CreateArrayLiteral(expr->constant_elements(),
-                                expr->literal_index(), flags);
+
+  size_t entry = builder()->AllocateConstantPoolEntry();
+  builder()->CreateArrayLiteral(entry, expr->literal_index(), flags);
+  array_literals_.push_back(std::make_pair(expr, entry));
+
   Register index, literal;
 
   // Evaluate all the non-constant subexpressions and store them into the
   // newly cloned array.
   bool literal_in_accumulator = true;
   for (int array_index = 0; array_index < expr->values()->length();
        array_index++) {
     Expression* subexpr = expr->values()->at(array_index);
     if (CompileTimeValue::IsCompileTimeValue(subexpr)) continue;
     DCHECK(!subexpr->IsSpread());
@@ skipping 1506 matching lines @@
 }
 
 Runtime::FunctionId BytecodeGenerator::StoreKeyedToSuperRuntimeId() {
   return is_strict(language_mode()) ? Runtime::kStoreKeyedToSuper_Strict
                                     : Runtime::kStoreKeyedToSuper_Sloppy;
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8