cca5e74a58
In many cases, the context that TurboFan's ASTGraphBuilder or subsequent reduction operations attaches to nodes does not need to be that exact context, but rather only needs to be one with the same native context, because it is used internally only to fetch the native context, e.g. for creating and throwing exceptions. This reducer recognizes common cases where the context that is specified for a node can be relaxed to a canonical, less specific one. This relaxed context can either be the enclosing function's context or a specific Module or Script context that is explicitly created within the function. This optimization is especially important for TurboFan-generated code stubs which use context specialization and inlining to generate optimal code. Without context relaxation, many extraneous moves are generated to pass exactly the right context to internal functions like ToNumber and AllocateHeapNumber, which only need the native context. By turning context relaxation on, these moves disappear because all these common internal context uses are unified to the context passed into the stub function, which is typically already in the correct context register and remains there for short stubs. It also eliminates the explicit use of a specialized context constant in the code stub in these cases, which could cause memory leaks. Review URL: https://codereview.chromium.org/1244583003 Cr-Commit-Position: refs/heads/master@{#29763}
378 lines
11 KiB
C++
378 lines
11 KiB
C++
// Copyright 2014 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "src/compiler/js-graph.h"
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#include "src/compiler/linkage.h"
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#include "src/compiler/liveness-analyzer.h"
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#include "src/compiler/node-matchers.h"
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#include "src/compiler/state-values-utils.h"
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#include "test/unittests/compiler/graph-unittest.h"
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#include "test/unittests/compiler/node-test-utils.h"
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using testing::MakeMatcher;
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using testing::MatcherInterface;
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using testing::MatchResultListener;
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using testing::StringMatchResultListener;
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namespace v8 {
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namespace internal {
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namespace compiler {
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class LivenessAnalysisTest : public GraphTest {
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public:
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explicit LivenessAnalysisTest(int locals_count = 4)
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: locals_count_(locals_count),
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machine_(zone(), kRepWord32),
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javascript_(zone()),
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jsgraph_(isolate(), graph(), common(), &javascript_, &machine_),
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analyzer_(locals_count, zone()),
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empty_values_(graph()->NewNode(common()->StateValues(0), 0, nullptr)),
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next_checkpoint_id_(0),
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current_block_(nullptr) {}
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protected:
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JSGraph* jsgraph() { return &jsgraph_; }
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LivenessAnalyzer* analyzer() { return &analyzer_; }
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void Run() {
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StateValuesCache cache(jsgraph());
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NonLiveFrameStateSlotReplacer replacer(&cache,
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jsgraph()->UndefinedConstant(),
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analyzer()->local_count(), zone());
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analyzer()->Run(&replacer);
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}
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Node* Checkpoint() {
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int ast_num = next_checkpoint_id_++;
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int first_const = intconst_from_bailout_id(ast_num, locals_count_);
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const Operator* locals_op = common()->StateValues(locals_count_);
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ZoneVector<Node*> local_inputs(locals_count_, nullptr, zone());
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for (int i = 0; i < locals_count_; i++) {
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local_inputs[i] = jsgraph()->Int32Constant(i + first_const);
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}
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Node* locals =
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graph()->NewNode(locals_op, locals_count_, &local_inputs.front());
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const FrameStateFunctionInfo* state_info =
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common()->CreateFrameStateFunctionInfo(
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FrameStateType::kJavaScriptFunction, 0, locals_count_,
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Handle<SharedFunctionInfo>(), CALL_MAINTAINS_NATIVE_CONTEXT);
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const Operator* op = common()->FrameState(
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BailoutId(ast_num), OutputFrameStateCombine::Ignore(), state_info);
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Node* result = graph()->NewNode(op, empty_values_, locals, empty_values_,
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jsgraph()->UndefinedConstant(),
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jsgraph()->UndefinedConstant());
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current_block_->Checkpoint(result);
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return result;
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}
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void Bind(int var) { current_block()->Bind(var); }
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void Lookup(int var) { current_block()->Lookup(var); }
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class CheckpointMatcher : public MatcherInterface<Node*> {
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public:
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explicit CheckpointMatcher(const char* liveness, Node* empty_values,
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int locals_count, Node* replacement)
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: liveness_(liveness),
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empty_values_(empty_values),
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locals_count_(locals_count),
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replacement_(replacement) {}
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void DescribeTo(std::ostream* os) const override {
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*os << "is a frame state with '" << liveness_
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<< "' liveness, empty "
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"parameters and empty expression stack";
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}
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bool MatchAndExplain(Node* frame_state,
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MatchResultListener* listener) const override {
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if (frame_state == NULL) {
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*listener << "which is NULL";
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return false;
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}
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DCHECK(frame_state->opcode() == IrOpcode::kFrameState);
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FrameStateInfo state_info = OpParameter<FrameStateInfo>(frame_state);
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int ast_num = state_info.bailout_id().ToInt();
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int first_const = intconst_from_bailout_id(ast_num, locals_count_);
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if (empty_values_ != frame_state->InputAt(0)) {
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*listener << "whose parameters are " << frame_state->InputAt(0)
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<< " but should have been " << empty_values_ << " (empty)";
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return false;
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}
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if (empty_values_ != frame_state->InputAt(2)) {
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*listener << "whose expression stack is " << frame_state->InputAt(2)
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<< " but should have been " << empty_values_ << " (empty)";
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return false;
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}
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StateValuesAccess locals(frame_state->InputAt(1));
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if (locals_count_ != static_cast<int>(locals.size())) {
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*listener << "whose number of locals is " << locals.size()
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<< " but should have been " << locals_count_;
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return false;
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}
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int i = 0;
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for (StateValuesAccess::TypedNode value : locals) {
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if (liveness_[i] == 'L') {
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StringMatchResultListener value_listener;
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if (value.node == replacement_) {
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*listener << "whose local #" << i << " was " << value.node->opcode()
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<< " but should have been 'undefined'";
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return false;
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} else if (!IsInt32Constant(first_const + i)
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.MatchAndExplain(value.node, &value_listener)) {
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*listener << "whose local #" << i << " does not match";
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if (value_listener.str() != "") {
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*listener << ", " << value_listener.str();
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}
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return false;
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}
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} else if (liveness_[i] == '.') {
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if (value.node != replacement_) {
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*listener << "whose local #" << i << " is " << value.node
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<< " but should have been " << replacement_
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<< " (undefined)";
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return false;
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}
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} else {
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UNREACHABLE();
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}
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i++;
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}
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return true;
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}
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private:
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const char* liveness_;
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Node* empty_values_;
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int locals_count_;
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Node* replacement_;
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};
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Matcher<Node*> IsCheckpointModuloLiveness(const char* liveness) {
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return MakeMatcher(new CheckpointMatcher(liveness, empty_values_,
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locals_count_,
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jsgraph()->UndefinedConstant()));
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}
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LivenessAnalyzerBlock* current_block() { return current_block_; }
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void set_current_block(LivenessAnalyzerBlock* block) {
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current_block_ = block;
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}
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private:
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static int intconst_from_bailout_id(int ast_num, int locals_count) {
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return (locals_count + 1) * ast_num + 1;
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}
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int locals_count_;
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MachineOperatorBuilder machine_;
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JSOperatorBuilder javascript_;
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JSGraph jsgraph_;
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LivenessAnalyzer analyzer_;
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Node* empty_values_;
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int next_checkpoint_id_;
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LivenessAnalyzerBlock* current_block_;
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};
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TEST_F(LivenessAnalysisTest, EmptyBlock) {
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set_current_block(analyzer()->NewBlock());
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Node* c1 = Checkpoint();
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Run();
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// Nothing is live.
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EXPECT_THAT(c1, IsCheckpointModuloLiveness("...."));
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}
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TEST_F(LivenessAnalysisTest, SimpleLookup) {
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set_current_block(analyzer()->NewBlock());
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Node* c1 = Checkpoint();
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Lookup(1);
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Node* c2 = Checkpoint();
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Run();
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EXPECT_THAT(c1, IsCheckpointModuloLiveness(".L.."));
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EXPECT_THAT(c2, IsCheckpointModuloLiveness("...."));
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}
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TEST_F(LivenessAnalysisTest, DiamondLookups) {
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// Start block.
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LivenessAnalyzerBlock* start = analyzer()->NewBlock();
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set_current_block(start);
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Node* c1_start = Checkpoint();
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// First branch.
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LivenessAnalyzerBlock* b1 = analyzer()->NewBlock(start);
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set_current_block(b1);
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Node* c1_b1 = Checkpoint();
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Lookup(1);
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Node* c2_b1 = Checkpoint();
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Lookup(3);
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Node* c3_b1 = Checkpoint();
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// Second branch.
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LivenessAnalyzerBlock* b2 = analyzer()->NewBlock(start);
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set_current_block(b2);
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Node* c1_b2 = Checkpoint();
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Lookup(3);
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Node* c2_b2 = Checkpoint();
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Lookup(2);
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Node* c3_b2 = Checkpoint();
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// Merge block.
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LivenessAnalyzerBlock* m = analyzer()->NewBlock(b1);
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m->AddPredecessor(b2);
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set_current_block(m);
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Node* c1_m = Checkpoint();
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Lookup(0);
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Node* c2_m = Checkpoint();
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Run();
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EXPECT_THAT(c1_start, IsCheckpointModuloLiveness("LLLL"));
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EXPECT_THAT(c1_b1, IsCheckpointModuloLiveness("LL.L"));
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EXPECT_THAT(c2_b1, IsCheckpointModuloLiveness("L..L"));
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EXPECT_THAT(c3_b1, IsCheckpointModuloLiveness("L..."));
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EXPECT_THAT(c1_b2, IsCheckpointModuloLiveness("L.LL"));
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EXPECT_THAT(c2_b2, IsCheckpointModuloLiveness("L.L."));
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EXPECT_THAT(c3_b2, IsCheckpointModuloLiveness("L..."));
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EXPECT_THAT(c1_m, IsCheckpointModuloLiveness("L..."));
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EXPECT_THAT(c2_m, IsCheckpointModuloLiveness("...."));
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}
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TEST_F(LivenessAnalysisTest, DiamondLookupsAndBinds) {
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// Start block.
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LivenessAnalyzerBlock* start = analyzer()->NewBlock();
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set_current_block(start);
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Node* c1_start = Checkpoint();
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Bind(0);
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Node* c2_start = Checkpoint();
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// First branch.
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LivenessAnalyzerBlock* b1 = analyzer()->NewBlock(start);
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set_current_block(b1);
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Node* c1_b1 = Checkpoint();
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Bind(2);
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Bind(1);
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Node* c2_b1 = Checkpoint();
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Bind(3);
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Node* c3_b1 = Checkpoint();
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// Second branch.
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LivenessAnalyzerBlock* b2 = analyzer()->NewBlock(start);
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set_current_block(b2);
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Node* c1_b2 = Checkpoint();
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Lookup(2);
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Node* c2_b2 = Checkpoint();
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Bind(2);
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Bind(3);
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Node* c3_b2 = Checkpoint();
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// Merge block.
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LivenessAnalyzerBlock* m = analyzer()->NewBlock(b1);
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m->AddPredecessor(b2);
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set_current_block(m);
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Node* c1_m = Checkpoint();
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Lookup(0);
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Lookup(1);
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Lookup(2);
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Lookup(3);
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Node* c2_m = Checkpoint();
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Run();
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EXPECT_THAT(c1_start, IsCheckpointModuloLiveness(".LL."));
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EXPECT_THAT(c2_start, IsCheckpointModuloLiveness("LLL."));
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EXPECT_THAT(c1_b1, IsCheckpointModuloLiveness("L..."));
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EXPECT_THAT(c2_b1, IsCheckpointModuloLiveness("LLL."));
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EXPECT_THAT(c3_b1, IsCheckpointModuloLiveness("LLLL"));
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EXPECT_THAT(c1_b2, IsCheckpointModuloLiveness("LLL."));
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EXPECT_THAT(c2_b2, IsCheckpointModuloLiveness("LL.."));
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EXPECT_THAT(c3_b2, IsCheckpointModuloLiveness("LLLL"));
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EXPECT_THAT(c1_m, IsCheckpointModuloLiveness("LLLL"));
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EXPECT_THAT(c2_m, IsCheckpointModuloLiveness("...."));
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}
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TEST_F(LivenessAnalysisTest, SimpleLoop) {
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// Start block.
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LivenessAnalyzerBlock* start = analyzer()->NewBlock();
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set_current_block(start);
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Node* c1_start = Checkpoint();
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Bind(0);
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Bind(1);
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Bind(2);
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Bind(3);
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Node* c2_start = Checkpoint();
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// Loop header block.
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LivenessAnalyzerBlock* header = analyzer()->NewBlock(start);
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set_current_block(header);
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Node* c1_header = Checkpoint();
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Lookup(0);
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Bind(2);
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Node* c2_header = Checkpoint();
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// Inside-loop block.
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LivenessAnalyzerBlock* in_loop = analyzer()->NewBlock(header);
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set_current_block(in_loop);
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Node* c1_in_loop = Checkpoint();
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Bind(0);
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Lookup(3);
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Node* c2_in_loop = Checkpoint();
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// Add back edge.
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header->AddPredecessor(in_loop);
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// After-loop block.
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LivenessAnalyzerBlock* end = analyzer()->NewBlock(header);
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set_current_block(end);
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Node* c1_end = Checkpoint();
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Lookup(1);
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Lookup(2);
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Node* c2_end = Checkpoint();
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Run();
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EXPECT_THAT(c1_start, IsCheckpointModuloLiveness("...."));
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EXPECT_THAT(c2_start, IsCheckpointModuloLiveness("LL.L"));
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EXPECT_THAT(c1_header, IsCheckpointModuloLiveness("LL.L"));
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EXPECT_THAT(c2_header, IsCheckpointModuloLiveness(".LLL"));
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EXPECT_THAT(c1_in_loop, IsCheckpointModuloLiveness(".L.L"));
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EXPECT_THAT(c2_in_loop, IsCheckpointModuloLiveness("LL.L"));
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EXPECT_THAT(c1_end, IsCheckpointModuloLiveness(".LL."));
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EXPECT_THAT(c2_end, IsCheckpointModuloLiveness("...."));
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}
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} // namespace compiler
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} // namespace internal
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} // namespace v8
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