[turbofan] Variable liveness analysis for deopt

test/unittests/compiler/liveness-analyzer-unittest.cc

+// 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-graph.h"
+#include "src/compiler/linkage.h"
+#include "src/compiler/liveness-analyzer.h"
+#include "src/compiler/node-matchers.h"
+#include "test/unittests/compiler/graph-unittest.h"
+#include "test/unittests/compiler/node-test-utils.h"
+
+using testing::MakeMatcher;
+using testing::MatcherInterface;
+using testing::MatchResultListener;
+using testing::StringMatchResultListener;
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+class LivenessAnalysisTest : public GraphTest {
+ public:
+  explicit LivenessAnalysisTest(int locals_count = 4)
+      : locals_count_(locals_count),
+        machine_(zone(), kRepWord32),
+        javascript_(zone()),
+        jsgraph_(isolate(), graph(), common(), &javascript_, &machine_),
+        analyzer_(locals_count, zone()),
+        empty_values_(graph()->NewNode(common()->StateValues(0), 0, nullptr)),
+        next_checkpoint_id_(0),
+        current_block_(nullptr) {}
+
+
+ protected:
+  JSGraph* jsgraph() { return &jsgraph_; }
+
+  LivenessAnalyzer* analyzer() { return &analyzer_; }
+  void Run() {
+    FrameStateRelaxer relaxer(&jsgraph_, jsgraph_.UndefinedConstant(),
+                              analyzer()->local_count(), zone());
+    analyzer()->Run(&relaxer);
+  }
+
+  Node* Checkpoint() {
+    int ast_num = next_checkpoint_id_++;
+    int first_const = intconst_from_bailout_id(ast_num, locals_count_);
+
+    const Operator* locals_op = common()->StateValues(locals_count_);
+
+    ZoneVector<Node*> local_inputs(locals_count_, nullptr, zone());
+    for (int i = 0; i < locals_count_; i++) {
+      local_inputs[i] = jsgraph()->Int32Constant(i + first_const);
+    }
+    Node* locals =
+        graph()->NewNode(locals_op, locals_count_, &local_inputs.front());
+
+    const Operator* op = common()->FrameState(
+        JS_FRAME, BailoutId(ast_num), OutputFrameStateCombine::Ignore());
+    Node* result = graph()->NewNode(op, empty_values_, locals, empty_values_,
+                                    jsgraph()->UndefinedConstant(),
+                                    jsgraph()->UndefinedConstant());
+
+    current_block_->Checkpoint(result);
+    return result;
+  }
+
+  void Bind(int var) { current_block()->Bind(var); }
+  void Lookup(int var) { current_block()->Lookup(var); }
+
+  class CheckpointMatcher : public MatcherInterface<Node*> {
+   public:
+    explicit CheckpointMatcher(const char* liveness, Node* empty_values,
+                               int locals_count, Node* replacement)
+        : liveness_(liveness),
+          empty_values_(empty_values),
+          locals_count_(locals_count),
+          replacement_(replacement) {}
+
+    void DescribeTo(std::ostream* os) const OVERRIDE {
+      *os << "is a frame state with '" << liveness_
+          << "' liveness, empty "
+             "parameters and empty expression stack";
+    }
+
+    bool MatchAndExplain(Node* frame_state,
+                         MatchResultListener* listener) const OVERRIDE {
+      if (frame_state == NULL) {
+        *listener << "which is NULL";
+        return false;
+      }
+      DCHECK(frame_state->opcode() == IrOpcode::kFrameState);
+
+      FrameStateCallInfo state_info =
+          OpParameter<FrameStateCallInfo>(frame_state);
+      int ast_num = state_info.bailout_id().ToInt();
+      int first_const = intconst_from_bailout_id(ast_num, locals_count_);
+
+      if (empty_values_ != frame_state->InputAt(0)) {
+        *listener << "whose parameters are " << frame_state->InputAt(0)
+                  << " but should have been " << empty_values_ << " (empty)";
+        return false;
+      }
+      if (empty_values_ != frame_state->InputAt(2)) {
+        *listener << "whose expression stack is " << frame_state->InputAt(2)
+                  << " but should have been " << empty_values_ << " (empty)";
+        return false;
+      }
+      Node* locals = frame_state->InputAt(1);
+      DCHECK(locals->opcode() == IrOpcode::kStateValues);
+      if (locals_count_ != locals->InputCount()) {
+        *listener << "whose number of locals is " << locals->InputCount()
+                  << " but should have been " << locals_count_;
+        return false;
+      }
+      for (int i = 0; i < locals_count_; i++) {
+        Node* value = locals->InputAt(i);
+        if (liveness_[i] == 'L') {
+          StringMatchResultListener value_listener;
+          if (value == replacement_) {
+            *listener << "whose local #" << i << " was " << value->opcode()
+                      << " but should have been 'undefined'";
+            return false;
+          } else if (!IsInt32Constant(first_const + i)
+                          .MatchAndExplain(value, &value_listener)) {
+            *listener << "whose local #" << i << " does not match";
+            if (value_listener.str() != "") {
+              *listener << ", " << value_listener.str();
+            }
+            return false;
+          }
+        } else if (liveness_[i] == '.') {
+          if (value != replacement_) {
+            *listener << "whose local #" << i << " is " << value
+                      << " but should have been " << replacement_
+                      << " (undefined)";
+            return false;
+          }
+        } else {
+          UNREACHABLE();
+        }
+      }
+      return true;
+    }
+
+   private:
+    const char* liveness_;
+    Node* empty_values_;
+    int locals_count_;
+    Node* replacement_;
+  };
+
+  Matcher<Node*> IsCheckpointModuloLiveness(const char* liveness) {
+    return MakeMatcher(new CheckpointMatcher(liveness, empty_values_,
+                                             locals_count_,
+                                             jsgraph()->UndefinedConstant()));
+  }
+
+  LivenessAnalyzerBlock* current_block() { return current_block_; }
+  void set_current_block(LivenessAnalyzerBlock* block) {
+    current_block_ = block;
+  }
+
+ private:
+  static int intconst_from_bailout_id(int ast_num, int locals_count) {
+    return (locals_count + 1) * ast_num + 1;
+  }
+
+  int locals_count_;
+  MachineOperatorBuilder machine_;
+  JSOperatorBuilder javascript_;
+  JSGraph jsgraph_;
+  LivenessAnalyzer analyzer_;
+  Node* empty_values_;
+  int next_checkpoint_id_;
+  LivenessAnalyzerBlock* current_block_;
+};
+
+
+TEST_F(LivenessAnalysisTest, EmptyBlock) {
+  set_current_block(analyzer()->New());
+
+  Node* c1 = Checkpoint();
+
+  Run();
+
+  // Nothing is live.
+  EXPECT_THAT(c1, IsCheckpointModuloLiveness("...."));
+}
+
+
+TEST_F(LivenessAnalysisTest, SimpleLookup) {
+  set_current_block(analyzer()->New());
+
+  Node* c1 = Checkpoint();
+  Lookup(1);
+  Node* c2 = Checkpoint();
+
+  Run();
+
+  EXPECT_THAT(c1, IsCheckpointModuloLiveness(".L.."));
+  EXPECT_THAT(c2, IsCheckpointModuloLiveness("...."));
+}
+
+
+TEST_F(LivenessAnalysisTest, DiamondLookups) {
+  // Start block.
+  LivenessAnalyzerBlock* start = analyzer()->New();
+  set_current_block(start);
+  Node* c1_start = Checkpoint();
+
+  // First branch.
+  LivenessAnalyzerBlock* b1 = analyzer()->New(start);
+  set_current_block(b1);
+
+  Node* c1_b1 = Checkpoint();
+  Lookup(1);
+  Node* c2_b1 = Checkpoint();
+  Lookup(3);
+  Node* c3_b1 = Checkpoint();
+
+  // Second branch.
+  LivenessAnalyzerBlock* b2 = analyzer()->New(start);
+  set_current_block(b2);
+
+  Node* c1_b2 = Checkpoint();
+  Lookup(3);
+  Node* c2_b2 = Checkpoint();
+  Lookup(2);
+  Node* c3_b2 = Checkpoint();
+
+  // Merge block.
+  LivenessAnalyzerBlock* m = analyzer()->New(b1);
+  m->AddPredecessor(b2);
+  set_current_block(m);
+  Node* c1_m = Checkpoint();
+  Lookup(0);
+  Node* c2_m = Checkpoint();
+
+  Run();
+
+  EXPECT_THAT(c1_start, IsCheckpointModuloLiveness("LLLL"));
+
+  EXPECT_THAT(c1_b1, IsCheckpointModuloLiveness("LL.L"));
+  EXPECT_THAT(c2_b1, IsCheckpointModuloLiveness("L..L"));
+  EXPECT_THAT(c3_b1, IsCheckpointModuloLiveness("L..."));
+
+  EXPECT_THAT(c1_b2, IsCheckpointModuloLiveness("L.LL"));
+  EXPECT_THAT(c2_b2, IsCheckpointModuloLiveness("L.L."));
+  EXPECT_THAT(c3_b2, IsCheckpointModuloLiveness("L..."));
+
+  EXPECT_THAT(c1_m, IsCheckpointModuloLiveness("L..."));
+  EXPECT_THAT(c2_m, IsCheckpointModuloLiveness("...."));
+}
+
+
+TEST_F(LivenessAnalysisTest, DiamondLookupsAndBinds) {
+  // Start block.
+  LivenessAnalyzerBlock* start = analyzer()->New();
+  set_current_block(start);
+  Node* c1_start = Checkpoint();
+  Bind(0);
+  Node* c2_start = Checkpoint();
+
+  // First branch.
+  LivenessAnalyzerBlock* b1 = analyzer()->New(start);
+  set_current_block(b1);
+
+  Node* c1_b1 = Checkpoint();
+  Bind(2);
+  Bind(1);
+  Node* c2_b1 = Checkpoint();
+  Bind(3);
+  Node* c3_b1 = Checkpoint();
+
+  // Second branch.
+  LivenessAnalyzerBlock* b2 = analyzer()->New(start);
+  set_current_block(b2);
+
+  Node* c1_b2 = Checkpoint();
+  Lookup(2);
+  Node* c2_b2 = Checkpoint();
+  Bind(2);
+  Bind(3);
+  Node* c3_b2 = Checkpoint();
+
+  // Merge block.
+  LivenessAnalyzerBlock* m = analyzer()->New(b1);
+  m->AddPredecessor(b2);
+  set_current_block(m);
+  Node* c1_m = Checkpoint();
+  Lookup(0);
+  Lookup(1);
+  Lookup(2);
+  Lookup(3);
+  Node* c2_m = Checkpoint();
+
+  Run();
+
+  EXPECT_THAT(c1_start, IsCheckpointModuloLiveness(".LL."));
+  EXPECT_THAT(c2_start, IsCheckpointModuloLiveness("LLL."));
+
+  EXPECT_THAT(c1_b1, IsCheckpointModuloLiveness("L..."));
+  EXPECT_THAT(c2_b1, IsCheckpointModuloLiveness("LLL."));
+  EXPECT_THAT(c3_b1, IsCheckpointModuloLiveness("LLLL"));
+
+  EXPECT_THAT(c1_b2, IsCheckpointModuloLiveness("LLL."));
+  EXPECT_THAT(c2_b2, IsCheckpointModuloLiveness("LL.."));
+  EXPECT_THAT(c3_b2, IsCheckpointModuloLiveness("LLLL"));
+
+  EXPECT_THAT(c1_m, IsCheckpointModuloLiveness("LLLL"));
+  EXPECT_THAT(c2_m, IsCheckpointModuloLiveness("...."));
+}
+
+
+TEST_F(LivenessAnalysisTest, SimpleLoop) {
+  // Start block.
+  LivenessAnalyzerBlock* start = analyzer()->New();
+  set_current_block(start);
+  Node* c1_start = Checkpoint();
+  Bind(0);
+  Bind(1);
+  Bind(2);
+  Bind(3);
+  Node* c2_start = Checkpoint();
+
+  // Loop header block.
+  LivenessAnalyzerBlock* header = analyzer()->New(start);
+  set_current_block(header);
+  Node* c1_header = Checkpoint();
+  Lookup(0);
+  Bind(2);
+  Node* c2_header = Checkpoint();
+
+  // Inside-loop block.
+  LivenessAnalyzerBlock* in_loop = analyzer()->New(header);
+  set_current_block(in_loop);
+  Node* c1_in_loop = Checkpoint();
+  Bind(0);
+  Lookup(3);
+  Node* c2_in_loop = Checkpoint();
+
+  // Add back edge.
+  header->AddPredecessor(in_loop);
+
+  // After-loop block.
+  LivenessAnalyzerBlock* end = analyzer()->New(header);
+  set_current_block(end);
+  Node* c1_end = Checkpoint();
+  Lookup(1);
+  Lookup(2);
+  Node* c2_end = Checkpoint();
+
+  Run();
+
+  EXPECT_THAT(c1_start, IsCheckpointModuloLiveness("...."));
+  EXPECT_THAT(c2_start, IsCheckpointModuloLiveness("LL.L"));
+
+  EXPECT_THAT(c1_header, IsCheckpointModuloLiveness("LL.L"));
+  EXPECT_THAT(c2_header, IsCheckpointModuloLiveness(".LLL"));
+
+  EXPECT_THAT(c1_in_loop, IsCheckpointModuloLiveness(".L.L"));
+  EXPECT_THAT(c2_in_loop, IsCheckpointModuloLiveness("LL.L"));
+
+  EXPECT_THAT(c1_end, IsCheckpointModuloLiveness(".LL."));
+  EXPECT_THAT(c2_end, IsCheckpointModuloLiveness("...."));
+}
+
+}  // namespace compiler
+}  // namespace internal
+}  // namespace v8