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src/compiler/verifier.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/verifier.h"
+
+#include "src/compiler/generic-algorithm.h"
+#include "src/compiler/generic-node-inl.h"
+#include "src/compiler/generic-node.h"
+#include "src/compiler/graph-inl.h"
+#include "src/compiler/graph.h"
+#include "src/compiler/node.h"
+#include "src/compiler/node-properties-inl.h"
+#include "src/compiler/node-properties.h"
+#include "src/compiler/opcodes.h"
+#include "src/compiler/operator.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+
+static bool IsDefUseChainLinkPresent(Node* def, Node* use) {
+  Node::Uses uses = def->uses();
+  for (Node::Uses::iterator it = uses.begin(); it != uses.end(); ++it) {
+    if (*it == use) return true;
+  }
+  return false;
+}
+
+
+static bool IsUseDefChainLinkPresent(Node* def, Node* use) {
+  Node::Inputs inputs = use->inputs();
+  for (Node::Inputs::iterator it = inputs.begin(); it != inputs.end(); ++it) {
+    if (*it == def) return true;
+  }
+  return false;
+}
+
+
+class Verifier::Visitor : public NullNodeVisitor {
+ public:
+  explicit Visitor(Zone* zone)
+      : reached_from_start(NodeSet::key_compare(),
+                           NodeSet::allocator_type(zone)),
+        reached_from_end(NodeSet::key_compare(),
+                         NodeSet::allocator_type(zone)) {}
+
+  // Fulfills the PreNodeCallback interface.
+  GenericGraphVisit::Control Pre(Node* node);
+
+  bool from_start;
+  NodeSet reached_from_start;
+  NodeSet reached_from_end;
+};
+
+
+GenericGraphVisit::Control Verifier::Visitor::Pre(Node* node) {
+  int value_count = NodeProperties::GetValueInputCount(node);
+  int context_count = NodeProperties::GetContextInputCount(node);
+  int effect_count = NodeProperties::GetEffectInputCount(node);
+  int control_count = NodeProperties::GetControlInputCount(node);
+
+  // Verify number of inputs matches up.
+  int input_count = value_count + context_count + effect_count + control_count;
+  CHECK_EQ(input_count, node->InputCount());
+
+  // Verify all value inputs actually produce a value.
+  for (int i = 0; i < value_count; ++i) {
+    Node* value = NodeProperties::GetValueInput(node, i);
+    CHECK(NodeProperties::HasValueOutput(value));
+    CHECK(IsDefUseChainLinkPresent(value, node));
+    CHECK(IsUseDefChainLinkPresent(value, node));
+  }
+
+  // Verify all context inputs are value nodes.
+  for (int i = 0; i < context_count; ++i) {
+    Node* context = NodeProperties::GetContextInput(node);
+    CHECK(NodeProperties::HasValueOutput(context));
+    CHECK(IsDefUseChainLinkPresent(context, node));
+    CHECK(IsUseDefChainLinkPresent(context, node));
+  }
+
+  // Verify all effect inputs actually have an effect.
+  for (int i = 0; i < effect_count; ++i) {
+    Node* effect = NodeProperties::GetEffectInput(node);
+    CHECK(NodeProperties::HasEffectOutput(effect));
+    CHECK(IsDefUseChainLinkPresent(effect, node));
+    CHECK(IsUseDefChainLinkPresent(effect, node));
+  }
+
+  // Verify all control inputs are control nodes.
+  for (int i = 0; i < control_count; ++i) {
+    Node* control = NodeProperties::GetControlInput(node, i);
+    CHECK(NodeProperties::HasControlOutput(control));
+    CHECK(IsDefUseChainLinkPresent(control, node));
+    CHECK(IsUseDefChainLinkPresent(control, node));
+  }
+
+  // Verify all successors are projections if multiple value outputs exist.
+  if (NodeProperties::GetValueOutputCount(node) > 1) {
+    Node::Uses uses = node->uses();
+    for (Node::Uses::iterator it = uses.begin(); it != uses.end(); ++it) {
+      CHECK(!NodeProperties::IsValueEdge(it.edge()) ||
+            (*it)->opcode() == IrOpcode::kProjection);
+    }
+  }
+
+  switch (node->opcode()) {
+    case IrOpcode::kStart:
+      // Start has no inputs.
+      CHECK_EQ(0, input_count);
+      break;
+    case IrOpcode::kEnd:
+      // End has no outputs.
+      CHECK(!NodeProperties::HasValueOutput(node));
+      CHECK(!NodeProperties::HasEffectOutput(node));
+      CHECK(!NodeProperties::HasControlOutput(node));
+      break;
+    case IrOpcode::kDead:
+      // Dead is never connected to the graph.
+      UNREACHABLE();
+    case IrOpcode::kBranch: {
+      // Branch uses are IfTrue and IfFalse.
+      Node::Uses uses = node->uses();
+      bool got_true = false, got_false = false;
+      for (Node::Uses::iterator it = uses.begin(); it != uses.end(); ++it) {
+        CHECK(((*it)->opcode() == IrOpcode::kIfTrue && !got_true) ||
+              ((*it)->opcode() == IrOpcode::kIfFalse && !got_false));
+        if ((*it)->opcode() == IrOpcode::kIfTrue) got_true = true;
+        if ((*it)->opcode() == IrOpcode::kIfFalse) got_false = true;
+      }
+      // TODO(rossberg): Currently fails for various tests.
+      // CHECK(got_true && got_false);
+      break;
+    }
+    case IrOpcode::kIfTrue:
+    case IrOpcode::kIfFalse:
+      CHECK_EQ(IrOpcode::kBranch,
+               NodeProperties::GetControlInput(node, 0)->opcode());
+      break;
+    case IrOpcode::kLoop:
+    case IrOpcode::kMerge:
+      break;
+    case IrOpcode::kReturn:
+      // TODO(rossberg): check successor is End
+      break;
+    case IrOpcode::kThrow:
+      // TODO(rossberg): what are the constraints on these?
+      break;
+    case IrOpcode::kParameter:
+      // Parameters have no inputs.
+      CHECK_EQ(0, input_count);
+      break;
+    case IrOpcode::kInt32Constant:
+    case IrOpcode::kInt64Constant:
+    case IrOpcode::kFloat64Constant:
+    case IrOpcode::kExternalConstant:
+    case IrOpcode::kNumberConstant:
+    case IrOpcode::kHeapConstant:
+      // Constants have no inputs.
+      CHECK_EQ(0, input_count);
+      break;
+    case IrOpcode::kPhi: {
+      // Phi input count matches parent control node.
+      CHECK_EQ(1, control_count);
+      Node* control = NodeProperties::GetControlInput(node, 0);
+      CHECK_EQ(value_count, NodeProperties::GetControlInputCount(control));
+      break;
+    }
+    case IrOpcode::kEffectPhi: {
+      // EffectPhi input count matches parent control node.
+      CHECK_EQ(1, control_count);
+      Node* control = NodeProperties::GetControlInput(node, 0);
+      CHECK_EQ(effect_count, NodeProperties::GetControlInputCount(control));
+      break;
+    }
+    case IrOpcode::kLazyDeoptimization:
+      // TODO(jarin): what are the constraints on these?
+      break;
+    case IrOpcode::kDeoptimize:
+      // TODO(jarin): what are the constraints on these?
+      break;
+    case IrOpcode::kFrameState:
+      // TODO(jarin): what are the constraints on these?
+      break;
+    case IrOpcode::kCall:
+      // TODO(rossberg): what are the constraints on these?
+      break;
+    case IrOpcode::kContinuation:
+      // TODO(jarin): what are the constraints on these?
+      break;
+    case IrOpcode::kProjection: {
+      // Projection has an input that produces enough values.
+      int index = static_cast<Operator1<int>*>(node->op())->parameter();
+      Node* input = NodeProperties::GetValueInput(node, 0);
+      CHECK_GT(NodeProperties::GetValueOutputCount(input), index);
+      break;
+    }
+    default:
+      // TODO(rossberg): Check other node kinds.
+      break;
+  }
+
+  if (from_start) {
+    reached_from_start.insert(node);
+  } else {
+    reached_from_end.insert(node);
+  }
+
+  return GenericGraphVisit::CONTINUE;
+}
+
+
+void Verifier::Run(Graph* graph) {
+  Visitor visitor(graph->zone());
+
+  visitor.from_start = true;
+  graph->VisitNodeUsesFromStart(&visitor);
+  visitor.from_start = false;
+  graph->VisitNodeInputsFromEnd(&visitor);
+
+  // All control nodes reachable from end are reachable from start.
+  for (NodeSet::iterator it = visitor.reached_from_end.begin();
+       it != visitor.reached_from_end.end(); ++it) {
+    CHECK(!NodeProperties::IsControl(*it) ||
+          visitor.reached_from_start.count(*it));
+  }
+}
+}
+}
+}  // namespace v8::internal::compiler