// Copyright 2014 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/compiler/js-inlining.h" #include "src/ast/ast.h" #include "src/codegen/compiler.h" #include "src/codegen/optimized-compilation-info.h" #include "src/codegen/tick-counter.h" #include "src/compiler/all-nodes.h" #include "src/compiler/bytecode-graph-builder.h" #include "src/compiler/common-operator.h" #include "src/compiler/compiler-source-position-table.h" #include "src/compiler/graph-reducer.h" #include "src/compiler/js-heap-broker.h" #include "src/compiler/js-operator.h" #include "src/compiler/node-matchers.h" #include "src/compiler/node-properties.h" #include "src/compiler/operator-properties.h" #include "src/compiler/simplified-operator.h" #include "src/execution/isolate-inl.h" #include "src/objects/feedback-cell-inl.h" #include "src/parsing/parse-info.h" namespace v8 { namespace internal { namespace compiler { namespace { // This is just to avoid some corner cases, especially since we allow recursive // inlining. static const int kMaxDepthForInlining = 50; } // namespace #define TRACE(x) \ do { \ if (FLAG_trace_turbo_inlining) { \ StdoutStream() << x << "\n"; \ } \ } while (false) // Provides convenience accessors for the common layout of nodes having either // the {JSCall} or the {JSConstruct} operator. class JSCallAccessor { public: explicit JSCallAccessor(Node* call) : call_(call) { DCHECK(call->opcode() == IrOpcode::kJSCall || call->opcode() == IrOpcode::kJSConstruct); } Node* target() { // Both, {JSCall} and {JSConstruct}, have same layout here. return call_->InputAt(0); } Node* receiver() { DCHECK_EQ(IrOpcode::kJSCall, call_->opcode()); return call_->InputAt(1); } Node* new_target() { DCHECK_EQ(IrOpcode::kJSConstruct, call_->opcode()); return call_->InputAt(formal_arguments() + 1); } Node* frame_state() { // Both, {JSCall} and {JSConstruct}, have frame state. return NodeProperties::GetFrameStateInput(call_); } int formal_arguments() { // Both, {JSCall} and {JSConstruct}, have two extra inputs: // - JSConstruct: Includes target function and new target. // - JSCall: Includes target function and receiver. return call_->op()->ValueInputCount() - 2; } CallFrequency const& frequency() const { return (call_->opcode() == IrOpcode::kJSCall) ? CallParametersOf(call_->op()).frequency() : ConstructParametersOf(call_->op()).frequency(); } private: Node* call_; }; Reduction JSInliner::InlineCall(Node* call, Node* new_target, Node* context, Node* frame_state, Node* start, Node* end, Node* exception_target, const NodeVector& uncaught_subcalls) { // The scheduler is smart enough to place our code; we just ensure {control} // becomes the control input of the start of the inlinee, and {effect} becomes // the effect input of the start of the inlinee. Node* control = NodeProperties::GetControlInput(call); Node* effect = NodeProperties::GetEffectInput(call); int const inlinee_new_target_index = static_cast<int>(start->op()->ValueOutputCount()) - 3; int const inlinee_arity_index = static_cast<int>(start->op()->ValueOutputCount()) - 2; int const inlinee_context_index = static_cast<int>(start->op()->ValueOutputCount()) - 1; // {inliner_inputs} counts JSFunction, receiver, arguments, but not // new target value, argument count, context, effect or control. int inliner_inputs = call->op()->ValueInputCount(); // Iterate over all uses of the start node. for (Edge edge : start->use_edges()) { Node* use = edge.from(); switch (use->opcode()) { case IrOpcode::kParameter: { int index = 1 + ParameterIndexOf(use->op()); DCHECK_LE(index, inlinee_context_index); if (index < inliner_inputs && index < inlinee_new_target_index) { // There is an input from the call, and the index is a value // projection but not the context, so rewire the input. Replace(use, call->InputAt(index)); } else if (index == inlinee_new_target_index) { // The projection is requesting the new target value. Replace(use, new_target); } else if (index == inlinee_arity_index) { // The projection is requesting the number of arguments. Replace(use, jsgraph()->Constant(inliner_inputs - 2)); } else if (index == inlinee_context_index) { // The projection is requesting the inlinee function context. Replace(use, context); } else { // Call has fewer arguments than required, fill with undefined. Replace(use, jsgraph()->UndefinedConstant()); } break; } default: if (NodeProperties::IsEffectEdge(edge)) { edge.UpdateTo(effect); } else if (NodeProperties::IsControlEdge(edge)) { edge.UpdateTo(control); } else if (NodeProperties::IsFrameStateEdge(edge)) { edge.UpdateTo(frame_state); } else { UNREACHABLE(); } break; } } if (exception_target != nullptr) { // Link uncaught calls in the inlinee to {exception_target} int subcall_count = static_cast<int>(uncaught_subcalls.size()); if (subcall_count > 0) { TRACE("Inlinee contains " << subcall_count << " calls without local exception handler; " << "linking to surrounding exception handler."); } NodeVector on_exception_nodes(local_zone_); for (Node* subcall : uncaught_subcalls) { Node* on_success = graph()->NewNode(common()->IfSuccess(), subcall); NodeProperties::ReplaceUses(subcall, subcall, subcall, on_success); NodeProperties::ReplaceControlInput(on_success, subcall); Node* on_exception = graph()->NewNode(common()->IfException(), subcall, subcall); on_exception_nodes.push_back(on_exception); } DCHECK_EQ(subcall_count, static_cast<int>(on_exception_nodes.size())); if (subcall_count > 0) { Node* control_output = graph()->NewNode(common()->Merge(subcall_count), subcall_count, &on_exception_nodes.front()); NodeVector values_effects(local_zone_); values_effects = on_exception_nodes; values_effects.push_back(control_output); Node* value_output = graph()->NewNode( common()->Phi(MachineRepresentation::kTagged, subcall_count), subcall_count + 1, &values_effects.front()); Node* effect_output = graph()->NewNode(common()->EffectPhi(subcall_count), subcall_count + 1, &values_effects.front()); ReplaceWithValue(exception_target, value_output, effect_output, control_output); } else { ReplaceWithValue(exception_target, exception_target, exception_target, jsgraph()->Dead()); } } NodeVector values(local_zone_); NodeVector effects(local_zone_); NodeVector controls(local_zone_); for (Node* const input : end->inputs()) { switch (input->opcode()) { case IrOpcode::kReturn: values.push_back(NodeProperties::GetValueInput(input, 1)); effects.push_back(NodeProperties::GetEffectInput(input)); controls.push_back(NodeProperties::GetControlInput(input)); break; case IrOpcode::kDeoptimize: case IrOpcode::kTerminate: case IrOpcode::kThrow: NodeProperties::MergeControlToEnd(graph(), common(), input); Revisit(graph()->end()); break; default: UNREACHABLE(); break; } } DCHECK_EQ(values.size(), effects.size()); DCHECK_EQ(values.size(), controls.size()); // Depending on whether the inlinee produces a value, we either replace value // uses with said value or kill value uses if no value can be returned. if (values.size() > 0) { int const input_count = static_cast<int>(controls.size()); Node* control_output = graph()->NewNode(common()->Merge(input_count), input_count, &controls.front()); values.push_back(control_output); effects.push_back(control_output); Node* value_output = graph()->NewNode( common()->Phi(MachineRepresentation::kTagged, input_count), static_cast<int>(values.size()), &values.front()); Node* effect_output = graph()->NewNode(common()->EffectPhi(input_count), static_cast<int>(effects.size()), &effects.front()); ReplaceWithValue(call, value_output, effect_output, control_output); return Changed(value_output); } else { ReplaceWithValue(call, jsgraph()->Dead(), jsgraph()->Dead(), jsgraph()->Dead()); return Changed(call); } } Node* JSInliner::CreateArtificialFrameState(Node* node, Node* outer_frame_state, int parameter_count, BailoutId bailout_id, FrameStateType frame_state_type, SharedFunctionInfoRef shared, Node* context) { const FrameStateFunctionInfo* state_info = common()->CreateFrameStateFunctionInfo( frame_state_type, parameter_count + 1, 0, shared.object()); const Operator* op = common()->FrameState( bailout_id, OutputFrameStateCombine::Ignore(), state_info); const Operator* op0 = common()->StateValues(0, SparseInputMask::Dense()); Node* node0 = graph()->NewNode(op0); NodeVector params(local_zone_); for (int parameter = 0; parameter < parameter_count + 1; ++parameter) { params.push_back(node->InputAt(1 + parameter)); } const Operator* op_param = common()->StateValues( static_cast<int>(params.size()), SparseInputMask::Dense()); Node* params_node = graph()->NewNode( op_param, static_cast<int>(params.size()), ¶ms.front()); if (!context) { context = jsgraph()->UndefinedConstant(); } return graph()->NewNode(op, params_node, node0, node0, context, node->InputAt(0), outer_frame_state); } namespace { // TODO(mstarzinger,verwaest): Move this predicate onto SharedFunctionInfo? bool NeedsImplicitReceiver(SharedFunctionInfoRef shared_info) { DisallowHeapAllocation no_gc; return !shared_info.construct_as_builtin() && !IsDerivedConstructor(shared_info.kind()); } } // namespace // Determines whether the call target of the given call {node} is statically // known and can be used as an inlining candidate. The {SharedFunctionInfo} of // the call target is provided (the exact closure might be unknown). base::Optional<SharedFunctionInfoRef> JSInliner::DetermineCallTarget( Node* node) { DCHECK(IrOpcode::IsInlineeOpcode(node->opcode())); HeapObjectMatcher match(node->InputAt(0)); // This reducer can handle both normal function calls as well a constructor // calls whenever the target is a constant function object, as follows: // - JSCall(target:constant, receiver, args...) // - JSConstruct(target:constant, args..., new.target) if (match.HasValue() && match.Ref(broker()).IsJSFunction()) { JSFunctionRef function = match.Ref(broker()).AsJSFunction(); // The function might have not been called yet. if (!function.has_feedback_vector()) { return base::nullopt; } // Disallow cross native-context inlining for now. This means that all parts // of the resulting code will operate on the same global object. This also // prevents cross context leaks, where we could inline functions from a // different context and hold on to that context (and closure) from the code // object. // TODO(turbofan): We might want to revisit this restriction later when we // have a need for this, and we know how to model different native contexts // in the same graph in a compositional way. if (!function.native_context().equals(broker()->native_context())) { return base::nullopt; } return function.shared(); } // This reducer can also handle calls where the target is statically known to // be the result of a closure instantiation operation, as follows: // - JSCall(JSCreateClosure[shared](context), receiver, args...) // - JSConstruct(JSCreateClosure[shared](context), args..., new.target) if (match.IsJSCreateClosure()) { CreateClosureParameters const& p = CreateClosureParametersOf(match.op()); // TODO(turbofan): We might consider to eagerly create the feedback vector // in such a case (in {DetermineCallContext} below) eventually. FeedbackCellRef cell(FeedbackCellRef(broker(), p.feedback_cell())); if (!cell.value().IsFeedbackVector()) return base::nullopt; return SharedFunctionInfoRef(broker(), p.shared_info()); } return base::nullopt; } // Determines statically known information about the call target (assuming that // the call target is known according to {DetermineCallTarget} above). The // following static information is provided: // - context : The context (as SSA value) bound by the call target. // - feedback_vector : The target is guaranteed to use this feedback vector. FeedbackVectorRef JSInliner::DetermineCallContext(Node* node, Node** context_out) { DCHECK(IrOpcode::IsInlineeOpcode(node->opcode())); HeapObjectMatcher match(node->InputAt(0)); if (match.HasValue() && match.Ref(broker()).IsJSFunction()) { JSFunctionRef function = match.Ref(broker()).AsJSFunction(); // This was already ensured by DetermineCallTarget CHECK(function.has_feedback_vector()); // The inlinee specializes to the context from the JSFunction object. *context_out = jsgraph()->Constant(function.context()); return function.feedback_vector(); } if (match.IsJSCreateClosure()) { CreateClosureParameters const& p = CreateClosureParametersOf(match.op()); // Load the feedback vector of the target by looking up its vector cell at // the instantiation site (we only decide to inline if it's populated). FeedbackCellRef cell(FeedbackCellRef(broker(), p.feedback_cell())); // The inlinee uses the locally provided context at instantiation. *context_out = NodeProperties::GetContextInput(match.node()); return cell.value().AsFeedbackVector(); } // Must succeed. UNREACHABLE(); } Reduction JSInliner::ReduceJSCall(Node* node) { DCHECK(IrOpcode::IsInlineeOpcode(node->opcode())); JSCallAccessor call(node); // Determine the call target. base::Optional<SharedFunctionInfoRef> shared_info(DetermineCallTarget(node)); if (!shared_info.has_value()) return NoChange(); DCHECK(shared_info->IsInlineable()); // Constructor must be constructable. if (node->opcode() == IrOpcode::kJSConstruct && !IsConstructable(shared_info->kind())) { TRACE("Not inlining " << *shared_info << " into " << info_->shared_info() << " because constructor is not constructable."); return NoChange(); } // Class constructors are callable, but [[Call]] will raise an exception. // See ES6 section 9.2.1 [[Call]] ( thisArgument, argumentsList ). if (node->opcode() == IrOpcode::kJSCall && IsClassConstructor(shared_info->kind())) { TRACE("Not inlining " << *shared_info << " into " << info_->shared_info() << " because callee is a class constructor."); return NoChange(); } // To ensure inlining always terminates, we have an upper limit on inlining // the nested calls. int nesting_level = 0; for (Node* frame_state = call.frame_state(); frame_state->opcode() == IrOpcode::kFrameState; frame_state = frame_state->InputAt(kFrameStateOuterStateInput)) { nesting_level++; if (nesting_level > kMaxDepthForInlining) { TRACE("Not inlining " << *shared_info << " into " << info_->shared_info() << " because call has exceeded the maximum depth for function " "inlining."); return NoChange(); } } Node* exception_target = nullptr; NodeProperties::IsExceptionalCall(node, &exception_target); // JSInliningHeuristic has already filtered candidates without a // BytecodeArray by calling SharedFunctionInfoRef::IsInlineable. For the ones // passing the IsInlineable check, The broker holds a reference to the // bytecode array, which prevents it from getting flushed. // Therefore, the following check should always hold true. CHECK(shared_info.value().is_compiled()); if (!FLAG_concurrent_inlining && info_->is_source_positions_enabled()) { SharedFunctionInfo::EnsureSourcePositionsAvailable(isolate(), shared_info->object()); } TRACE("Inlining " << *shared_info << " into " << info_->shared_info() << ((exception_target != nullptr) ? " (inside try-block)" : "")); // Determine the targets feedback vector and its context. Node* context; FeedbackVectorRef feedback_vector = DetermineCallContext(node, &context); if (FLAG_concurrent_inlining && !shared_info.value().IsSerializedForCompilation(feedback_vector)) { TRACE("Missed opportunity to inline a function (" << *shared_info << " with " << feedback_vector << ")"); return NoChange(); } // ---------------------------------------------------------------- // After this point, we've made a decision to inline this function. // We shall not bailout from inlining if we got here. BytecodeArrayRef bytecode_array = shared_info.value().GetBytecodeArray(); // Remember that we inlined this function. int inlining_id = info_->AddInlinedFunction( shared_info.value().object(), bytecode_array.object(), source_positions_->GetSourcePosition(node)); // Create the subgraph for the inlinee. Node* start; Node* end; { // Run the BytecodeGraphBuilder to create the subgraph. Graph::SubgraphScope scope(graph()); BytecodeGraphBuilderFlags flags( BytecodeGraphBuilderFlag::kSkipFirstStackCheck); if (info_->is_analyze_environment_liveness()) { flags |= BytecodeGraphBuilderFlag::kAnalyzeEnvironmentLiveness; } if (info_->is_bailout_on_uninitialized()) { flags |= BytecodeGraphBuilderFlag::kBailoutOnUninitialized; } { // TODO(mslekova): Remove the following once bytecode graph builder // is brokerized. Also, remove the context argument from // BuildGraphFromBytecode and extract it from the broker there. AllowHandleDereference allow_handle_deref; AllowHandleAllocation allow_handle_alloc; AllowHeapAllocation allow_heap_alloc; AllowCodeDependencyChange allow_code_dep_change; CallFrequency frequency = call.frequency(); Handle<NativeContext> native_context(info_->native_context(), isolate()); BuildGraphFromBytecode( broker(), zone(), bytecode_array.object(), shared_info.value().object(), feedback_vector.object(), BailoutId::None(), jsgraph(), frequency, source_positions_, native_context, inlining_id, flags, &info_->tick_counter()); } // Extract the inlinee start/end nodes. start = graph()->start(); end = graph()->end(); } // If we are inlining into a surrounding exception handler, we collect all // potentially throwing nodes within the inlinee that are not handled locally // by the inlinee itself. They are later wired into the surrounding handler. NodeVector uncaught_subcalls(local_zone_); if (exception_target != nullptr) { // Find all uncaught 'calls' in the inlinee. AllNodes inlined_nodes(local_zone_, end, graph()); for (Node* subnode : inlined_nodes.reachable) { // Every possibly throwing node should get {IfSuccess} and {IfException} // projections, unless there already is local exception handling. if (subnode->op()->HasProperty(Operator::kNoThrow)) continue; if (!NodeProperties::IsExceptionalCall(subnode)) { DCHECK_EQ(2, subnode->op()->ControlOutputCount()); uncaught_subcalls.push_back(subnode); } } } Node* frame_state = call.frame_state(); Node* new_target = jsgraph()->UndefinedConstant(); // Inline {JSConstruct} requires some additional magic. if (node->opcode() == IrOpcode::kJSConstruct) { // Swizzle the inputs of the {JSConstruct} node to look like inputs to a // normal {JSCall} node so that the rest of the inlining machinery // behaves as if we were dealing with a regular function invocation. new_target = call.new_target(); // Retrieve new target value input. node->RemoveInput(call.formal_arguments() + 1); // Drop new target. node->InsertInput(graph()->zone(), 1, new_target); // Insert nodes around the call that model the behavior required for a // constructor dispatch (allocate implicit receiver and check return value). // This models the behavior usually accomplished by our {JSConstructStub}. // Note that the context has to be the callers context (input to call node). // Also note that by splitting off the {JSCreate} piece of the constructor // call, we create an observable deoptimization point after the receiver // instantiation but before the invocation (i.e. inside {JSConstructStub} // where execution continues at {construct_stub_create_deopt_pc_offset}). Node* receiver = jsgraph()->TheHoleConstant(); // Implicit receiver. Node* context = NodeProperties::GetContextInput(node); if (NeedsImplicitReceiver(shared_info.value())) { Node* effect = NodeProperties::GetEffectInput(node); Node* control = NodeProperties::GetControlInput(node); Node* frame_state_inside = CreateArtificialFrameState( node, frame_state, call.formal_arguments(), BailoutId::ConstructStubCreate(), FrameStateType::kConstructStub, shared_info.value(), context); Node* create = graph()->NewNode(javascript()->Create(), call.target(), new_target, context, frame_state_inside, effect, control); uncaught_subcalls.push_back(create); // Adds {IfSuccess} & {IfException}. NodeProperties::ReplaceControlInput(node, create); NodeProperties::ReplaceEffectInput(node, create); // Placeholder to hold {node}'s value dependencies while {node} is // replaced. Node* dummy = graph()->NewNode(common()->Dead()); NodeProperties::ReplaceUses(node, dummy, node, node, node); Node* result; // Insert a check of the return value to determine whether the return // value or the implicit receiver should be selected as a result of the // call. Node* check = graph()->NewNode(simplified()->ObjectIsReceiver(), node); result = graph()->NewNode(common()->Select(MachineRepresentation::kTagged), check, node, create); receiver = create; // The implicit receiver. ReplaceWithValue(dummy, result); } else if (IsDerivedConstructor(shared_info->kind())) { Node* node_success = NodeProperties::FindSuccessfulControlProjection(node); Node* is_receiver = graph()->NewNode(simplified()->ObjectIsReceiver(), node); Node* branch_is_receiver = graph()->NewNode(common()->Branch(), is_receiver, node_success); Node* branch_is_receiver_true = graph()->NewNode(common()->IfTrue(), branch_is_receiver); Node* branch_is_receiver_false = graph()->NewNode(common()->IfFalse(), branch_is_receiver); branch_is_receiver_false = graph()->NewNode(javascript()->CallRuntime( Runtime::kThrowConstructorReturnedNonObject), context, NodeProperties::GetFrameStateInput(node), node, branch_is_receiver_false); uncaught_subcalls.push_back(branch_is_receiver_false); branch_is_receiver_false = graph()->NewNode(common()->Throw(), branch_is_receiver_false, branch_is_receiver_false); NodeProperties::MergeControlToEnd(graph(), common(), branch_is_receiver_false); ReplaceWithValue(node_success, node_success, node_success, branch_is_receiver_true); // Fix input destroyed by the above {ReplaceWithValue} call. NodeProperties::ReplaceControlInput(branch_is_receiver, node_success, 0); } node->ReplaceInput(1, receiver); // Insert a construct stub frame into the chain of frame states. This will // reconstruct the proper frame when deoptimizing within the constructor. frame_state = CreateArtificialFrameState( node, frame_state, call.formal_arguments(), BailoutId::ConstructStubInvoke(), FrameStateType::kConstructStub, shared_info.value(), context); } // Insert a JSConvertReceiver node for sloppy callees. Note that the context // passed into this node has to be the callees context (loaded above). if (node->opcode() == IrOpcode::kJSCall && is_sloppy(shared_info->language_mode()) && !shared_info->native()) { Node* effect = NodeProperties::GetEffectInput(node); if (NodeProperties::CanBePrimitive(broker(), call.receiver(), effect)) { CallParameters const& p = CallParametersOf(node->op()); Node* global_proxy = jsgraph()->Constant(broker()->native_context().global_proxy_object()); Node* receiver = effect = graph()->NewNode(simplified()->ConvertReceiver(p.convert_mode()), call.receiver(), global_proxy, effect, start); NodeProperties::ReplaceValueInput(node, receiver, 1); NodeProperties::ReplaceEffectInput(node, effect); } } // Insert argument adaptor frame if required. The callees formal parameter // count (i.e. value outputs of start node minus target, receiver, new target, // arguments count and context) have to match the number of arguments passed // to the call. int parameter_count = shared_info->internal_formal_parameter_count(); DCHECK_EQ(parameter_count, start->op()->ValueOutputCount() - 5); if (call.formal_arguments() != parameter_count) { frame_state = CreateArtificialFrameState( node, frame_state, call.formal_arguments(), BailoutId::None(), FrameStateType::kArgumentsAdaptor, shared_info.value()); } return InlineCall(node, new_target, context, frame_state, start, end, exception_target, uncaught_subcalls); } Graph* JSInliner::graph() const { return jsgraph()->graph(); } JSOperatorBuilder* JSInliner::javascript() const { return jsgraph()->javascript(); } CommonOperatorBuilder* JSInliner::common() const { return jsgraph()->common(); } SimplifiedOperatorBuilder* JSInliner::simplified() const { return jsgraph()->simplified(); } #undef TRACE } // namespace compiler } // namespace internal } // namespace v8