Better typing and type verification

src/compiler/typer.cc

Index: src/compiler/typer.cc
diff --git a/src/compiler/typer.cc b/src/compiler/typer.cc
index 73fe41d58291ff3dfbe0637b6dcc7c103b0041e9..f532355f4589315ca2cd0cb4f4ecefdbb6be8a22 100644
--- a/src/compiler/typer.cc
+++ b/src/compiler/typer.cc
@@ -14,7 +14,20 @@ namespace v8 {
 namespace internal {
 namespace compiler {
 
-Typer::Typer(Zone* zone) : zone_(zone) {
+
+class Typer::Decorator : public GraphDecorator {
+ public:
+  explicit Decorator(Typer* typer) : typer_(typer) {}
+  virtual void Decorate(Node* node);
+
+ private:
+  Typer* typer_;
+};
+
+
+Typer::Typer(Graph* graph, MaybeHandle<Context> context)
+    : graph_(graph), context_(context), decorator_(NULL) {
+  Zone* zone = this->zone();
   Type* number = Type::Number(zone);
   Type* signed32 = Type::Signed32(zone);
   Type* unsigned32 = Type::Unsigned32(zone);
@@ -62,39 +75,47 @@ Typer::Typer(Zone* zone) : zone_(zone) {
 }
 
 
+Typer::~Typer() {
+  if (decorator_) graph_->RemoveDecorator(decorator_);
+}
+
+
 class Typer::Visitor : public NullNodeVisitor {
  public:
-  Visitor(Typer* typer, MaybeHandle<Context> context)
-      : typer_(typer), context_(context) {}
+  explicit Visitor(Typer* typer) : typer_(typer) {}
 
   Bounds TypeNode(Node* node) {
     switch (node->opcode()) {
 #define DECLARE_CASE(x) case IrOpcode::k##x: return Type##x(node);
+      DECLARE_CASE(Start)
       VALUE_OP_LIST(DECLARE_CASE)
 #undef DECLARE_CASE
 
 #define DECLARE_CASE(x) case IrOpcode::k##x:
-      CONTROL_OP_LIST(DECLARE_CASE)
+      DECLARE_CASE(End)
+      INNER_CONTROL_OP_LIST(DECLARE_CASE)
 #undef DECLARE_CASE
       break;
     }
-    return Bounds(Type::None(zone()));
+    UNREACHABLE();
+    return Bounds();
   }
 
   Type* TypeConstant(Handle<Object> value);
 
  protected:
 #define DECLARE_METHOD(x) inline Bounds Type##x(Node* node);
+  DECLARE_METHOD(Start)
   VALUE_OP_LIST(DECLARE_METHOD)
 #undef DECLARE_METHOD
 
-  Bounds OperandType(Node* node, int i) {
-    return NodeProperties::GetBounds(NodeProperties::GetValueInput(node, i));
+  Bounds operand(Node* node, int i) {
+    Node* operand_node = NodeProperties::GetValueInput(node, i);
+    return GetBoundsOrNone(operand_node);
   }
 
-  Type* ContextType(Node* node) {
-    Bounds result =
-        NodeProperties::GetBounds(NodeProperties::GetContextInput(node));
+  Type* context_type(Node* node) {
+    Bounds result = GetBoundsOrNone(NodeProperties::GetContextInput(node));
     DCHECK(result.upper->Is(Type::Internal()));
     DCHECK(result.lower->Equals(result.upper));
     return result.upper;
@@ -102,35 +123,31 @@ class Typer::Visitor : public NullNodeVisitor {
 
   Zone* zone() { return typer_->zone(); }
   Isolate* isolate() { return typer_->isolate(); }
-  MaybeHandle<Context> context() { return context_; }
+  Graph* graph() { return typer_->graph(); }
+  MaybeHandle<Context> context() { return typer_->context(); }
 
  private:
   Typer* typer_;
-  MaybeHandle<Context> context_;
+
+  Bounds GetBoundsOrNone(Node* node) {
+    return NodeProperties::IsTyped(node)
+        ? NodeProperties::GetBounds(node) : Bounds(Type::None(zone()));
+  }
 };
 
 
 class Typer::RunVisitor : public Typer::Visitor {
  public:
-  RunVisitor(Typer* typer, MaybeHandle<Context> context)
-      : Visitor(typer, context),
+  explicit RunVisitor(Typer* typer)
+      : Visitor(typer),
         phis(NodeSet::key_compare(), NodeSet::allocator_type(typer->zone())) {}
 
-  GenericGraphVisit::Control Pre(Node* node) {
-    return NodeProperties::IsControl(node)
-        && node->opcode() != IrOpcode::kEnd
-        && node->opcode() != IrOpcode::kMerge
-        && node->opcode() != IrOpcode::kReturn
-        ? GenericGraphVisit::SKIP : GenericGraphVisit::CONTINUE;
-  }
-
   GenericGraphVisit::Control Post(Node* node) {
-    Bounds bounds = TypeNode(node);
-    if (node->opcode() == IrOpcode::kPhi) {
-      // Remember phis for least fixpoint iteration.
-      phis.insert(node);
-    } else {
+    if (OperatorProperties::HasValueOutput(node->op())) {
+      Bounds bounds = TypeNode(node);
       NodeProperties::SetBounds(node, bounds);
+      // Remember phis for least fixpoint iteration.
+      if (node->opcode() == IrOpcode::kPhi) phis.insert(node);
     }
     return GenericGraphVisit::CONTINUE;
   }
@@ -141,17 +158,20 @@ class Typer::RunVisitor : public Typer::Visitor {
 
 class Typer::NarrowVisitor : public Typer::Visitor {
  public:
-  NarrowVisitor(Typer* typer, MaybeHandle<Context> context)
-      : Visitor(typer, context) {}
+  explicit NarrowVisitor(Typer* typer) : Visitor(typer) {}
 
   GenericGraphVisit::Control Pre(Node* node) {
-    Bounds previous = NodeProperties::GetBounds(node);
-    Bounds bounds = TypeNode(node);
-    NodeProperties::SetBounds(node, Bounds::Both(bounds, previous, zone()));
-    DCHECK(bounds.Narrows(previous));
-    // Stop when nothing changed (but allow reentry in case it does later).
-    return previous.Narrows(bounds)
-        ? GenericGraphVisit::DEFER : GenericGraphVisit::REENTER;
+    if (OperatorProperties::HasValueOutput(node->op())) {
+      Bounds previous = NodeProperties::GetBounds(node);
+      Bounds bounds = TypeNode(node);
+      NodeProperties::SetBounds(node, Bounds::Both(bounds, previous, zone()));
+      DCHECK(bounds.Narrows(previous));
+      // Stop when nothing changed (but allow re-entry in case it does later).
+      return previous.Narrows(bounds)
+          ? GenericGraphVisit::DEFER : GenericGraphVisit::REENTER;
+    } else {
+      return GenericGraphVisit::SKIP;
+    }
   }
 
   GenericGraphVisit::Control Post(Node* node) {
@@ -162,18 +182,21 @@ class Typer::NarrowVisitor : public Typer::Visitor {
 
 class Typer::WidenVisitor : public Typer::Visitor {
  public:
-  WidenVisitor(Typer* typer, MaybeHandle<Context> context)
-      : Visitor(typer, context) {}
+  explicit WidenVisitor(Typer* typer) : Visitor(typer) {}
 
   GenericGraphVisit::Control Pre(Node* node) {
-    Bounds previous = NodeProperties::GetBounds(node);
-    Bounds bounds = TypeNode(node);
-    DCHECK(previous.lower->Is(bounds.lower));
-    DCHECK(previous.upper->Is(bounds.upper));
-    NodeProperties::SetBounds(node, bounds);  // TODO(rossberg): Either?
-    // Stop when nothing changed (but allow reentry in case it does later).
-    return bounds.Narrows(previous)
-        ? GenericGraphVisit::DEFER : GenericGraphVisit::REENTER;
+    if (OperatorProperties::HasValueOutput(node->op())) {
+      Bounds previous = NodeProperties::GetBounds(node);
+      Bounds bounds = TypeNode(node);
+      DCHECK(previous.lower->Is(bounds.lower));
+      DCHECK(previous.upper->Is(bounds.upper));
+      NodeProperties::SetBounds(node, bounds);  // TODO(rossberg): Either?
+      // Stop when nothing changed (but allow re-entry in case it does later).
+      return bounds.Narrows(previous)
+          ? GenericGraphVisit::DEFER : GenericGraphVisit::REENTER;
+    } else {
+      return GenericGraphVisit::SKIP;
+    }
   }
 
   GenericGraphVisit::Control Post(Node* node) {
@@ -182,36 +205,47 @@ class Typer::WidenVisitor : public Typer::Visitor {
 };
 
 
-void Typer::Run(Graph* graph, MaybeHandle<Context> context) {
-  RunVisitor typing(this, context);
-  graph->VisitNodeInputsFromEnd(&typing);
+void Typer::Run() {
+  RunVisitor typing(this);
+  graph_->VisitNodeInputsFromEnd(&typing);
   // Find least fixpoint.
-  for (NodeSetIter i = typing.phis.begin(); i != typing.phis.end(); ++i) {
-    Widen(graph, *i, context);
+  WidenVisitor widen(this);
+  for (NodeSetIter it = typing.phis.begin(); it != typing.phis.end(); ++it) {
+    graph_->VisitNodeUsesFrom(*it, &widen);
   }
+
+  DCHECK(decorator_ == NULL);
+  decorator_ = new (zone()) Decorator(this);
+  graph_->AddDecorator(decorator_);
 }
 
 
-void Typer::Narrow(Graph* graph, Node* start, MaybeHandle<Context> context) {
-  NarrowVisitor typing(this, context);
-  graph->VisitNodeUsesFrom(start, &typing);
+void Typer::Narrow(Node* start) {
+  NarrowVisitor typing(this);
+  graph_->VisitNodeUsesFrom(start, &typing);
 }
 
 
-void Typer::Widen(Graph* graph, Node* start, MaybeHandle<Context> context) {
-  WidenVisitor typing(this, context);
-  graph->VisitNodeUsesFrom(start, &typing);
+void Typer::Decorator::Decorate(Node* node) {
+  if (OperatorProperties::HasValueOutput(node->op())) {
+    Visitor typing(typer_);
+    Bounds bounds = typing.TypeNode(node);
+    NodeProperties::SetBounds(node, bounds);
+  }
 }
 
 
-void Typer::Init(Node* node) {
-  Visitor typing(this, MaybeHandle<Context>());
-  Bounds bounds = typing.TypeNode(node);
-  NodeProperties::SetBounds(node, bounds);
+// -----------------------------------------------------------------------------
+
+// Control operators.
+
+Bounds Typer::Visitor::TypeStart(Node* node) {
+  return Bounds(Type::Internal(zone()));
 }
 
 
 // Common operators.
+
 Bounds Typer::Visitor::TypeParameter(Node* node) {
   return Bounds::Unbounded(zone());
 }
@@ -254,39 +288,46 @@ Bounds Typer::Visitor::TypeExternalConstant(Node* node) {
 
 Bounds Typer::Visitor::TypePhi(Node* node) {
   int arity = OperatorProperties::GetValueInputCount(node->op());
-  Bounds bounds = OperandType(node, 0);
+  Bounds bounds = operand(node, 0);
   for (int i = 1; i < arity; ++i) {
-    bounds = Bounds::Either(bounds, OperandType(node, i), zone());
+    bounds = Bounds::Either(bounds, operand(node, i), zone());
   }
   return bounds;
 }
 
 
 Bounds Typer::Visitor::TypeEffectPhi(Node* node) {
-  return Bounds(Type::None(zone()));
+  UNREACHABLE();
+  return Bounds();
 }
 
 
 Bounds Typer::Visitor::TypeControlEffect(Node* node) {
-  return Bounds(Type::None(zone()));
+  UNREACHABLE();
+  return Bounds();
 }
 
 
 Bounds Typer::Visitor::TypeValueEffect(Node* node) {
-  return Bounds(Type::None(zone()));
+  UNREACHABLE();
+  return Bounds();
 }
 
 
-Bounds Typer::Visitor::TypeFinish(Node* node) { return OperandType(node, 0); }
+Bounds Typer::Visitor::TypeFinish(Node* node) {
+  return operand(node, 0);
+}
 
 
 Bounds Typer::Visitor::TypeFrameState(Node* node) {
-  return Bounds(Type::None(zone()));
+  UNREACHABLE();
+  return Bounds();
 }
 
 
 Bounds Typer::Visitor::TypeStateValues(Node* node) {
-  return Bounds(Type::None(zone()));
+  UNREACHABLE();
+  return Bounds();
 }
 
 
@@ -314,8 +355,8 @@ JS_COMPARE_BINOP_LIST(DEFINE_METHOD)
 // JS bitwise operators.
 
 Bounds Typer::Visitor::TypeJSBitwiseOr(Node* node) {
-  Bounds left = OperandType(node, 0);
-  Bounds right = OperandType(node, 1);
+  Bounds left = operand(node, 0);
+  Bounds right = operand(node, 1);
   Type* upper = Type::Union(left.upper, right.upper, zone());
   if (!upper->Is(Type::Signed32())) upper = Type::Signed32(zone());
   Type* lower = Type::Intersect(Type::SignedSmall(zone()), upper, zone());
@@ -324,8 +365,8 @@ Bounds Typer::Visitor::TypeJSBitwiseOr(Node* node) {
 
 
 Bounds Typer::Visitor::TypeJSBitwiseAnd(Node* node) {
-  Bounds left = OperandType(node, 0);
-  Bounds right = OperandType(node, 1);
+  Bounds left = operand(node, 0);
+  Bounds right = operand(node, 1);
   Type* upper = Type::Union(left.upper, right.upper, zone());
   if (!upper->Is(Type::Signed32())) upper = Type::Signed32(zone());
   Type* lower = Type::Intersect(Type::SignedSmall(zone()), upper, zone());
@@ -356,8 +397,8 @@ Bounds Typer::Visitor::TypeJSShiftRightLogical(Node* node) {
 // JS arithmetic operators.
 
 Bounds Typer::Visitor::TypeJSAdd(Node* node) {
-  Bounds left = OperandType(node, 0);
-  Bounds right = OperandType(node, 1);
+  Bounds left = operand(node, 0);
+  Bounds right = operand(node, 1);
   Type* lower =
       left.lower->Is(Type::None()) || right.lower->Is(Type::None()) ?
           Type::None(zone()) :
@@ -431,7 +472,7 @@ Bounds Typer::Visitor::TypeJSToName(Node* node) {
 
 
 Bounds Typer::Visitor::TypeJSToObject(Node* node) {
-  return Bounds(Type::None(zone()), Type::Object(zone()));
+  return Bounds(Type::None(zone()), Type::Receiver(zone()));
 }
 
 
@@ -443,8 +484,8 @@ Bounds Typer::Visitor::TypeJSCreate(Node* node) {
 
 
 Bounds Typer::Visitor::TypeJSLoadProperty(Node* node) {
-  Bounds object = OperandType(node, 0);
-  Bounds name = OperandType(node, 1);
+  Bounds object = operand(node, 0);
+  Bounds name = operand(node, 1);
   Bounds result = Bounds::Unbounded(zone());
   // TODO(rossberg): Use range types and sized array types to filter undefined.
   if (object.lower->IsArray() && name.lower->Is(Type::Integral32())) {
@@ -465,12 +506,14 @@ Bounds Typer::Visitor::TypeJSLoadNamed(Node* node) {
 
 
 Bounds Typer::Visitor::TypeJSStoreProperty(Node* node) {
-  return Bounds(Type::None(zone()));
+  UNREACHABLE();
+  return Bounds();
 }
 
 
 Bounds Typer::Visitor::TypeJSStoreNamed(Node* node) {
-  return Bounds(Type::None(zone()));
+  UNREACHABLE();
+  return Bounds();
 }
 
 
@@ -492,9 +535,11 @@ Bounds Typer::Visitor::TypeJSInstanceOf(Node* node) {
 // JS context operators.
 
 Bounds Typer::Visitor::TypeJSLoadContext(Node* node) {
-  Bounds outer = OperandType(node, 0);
-  DCHECK(outer.upper->Is(Type::Internal()));
-  DCHECK(outer.lower->Equals(outer.upper));
+  Bounds outer = operand(node, 0);
+  DCHECK(outer.upper->Maybe(Type::Internal()));
+  // TODO(rossberg): More precisely, instead of the above assertion, we should
+  // back-propagate the constraint that it has to be a subtype of Internal.
+
   ContextAccess access = OpParameter<ContextAccess>(node);
   Type* context_type = outer.upper;
   MaybeHandle<Context> context;
@@ -528,43 +573,44 @@ Bounds Typer::Visitor::TypeJSLoadContext(Node* node) {
 
 
 Bounds Typer::Visitor::TypeJSStoreContext(Node* node) {
-  return Bounds(Type::None(zone()));
+  UNREACHABLE();
+  return Bounds();
 }
 
 
 Bounds Typer::Visitor::TypeJSCreateFunctionContext(Node* node) {
-  Type* outer = ContextType(node);
+  Type* outer = context_type(node);
   return Bounds(Type::Context(outer, zone()));
 }
 
 
 Bounds Typer::Visitor::TypeJSCreateCatchContext(Node* node) {
-  Type* outer = ContextType(node);
+  Type* outer = context_type(node);
   return Bounds(Type::Context(outer, zone()));
 }
 
 
 Bounds Typer::Visitor::TypeJSCreateWithContext(Node* node) {
-  Type* outer = ContextType(node);
+  Type* outer = context_type(node);
   return Bounds(Type::Context(outer, zone()));
 }
 
 
 Bounds Typer::Visitor::TypeJSCreateBlockContext(Node* node) {
-  Type* outer = ContextType(node);
+  Type* outer = context_type(node);
   return Bounds(Type::Context(outer, zone()));
 }
 
 
 Bounds Typer::Visitor::TypeJSCreateModuleContext(Node* node) {
   // TODO(rossberg): this is probably incorrect
-  Type* outer = ContextType(node);
+  Type* outer = context_type(node);
   return Bounds(Type::Context(outer, zone()));
 }
 
 
 Bounds Typer::Visitor::TypeJSCreateGlobalContext(Node* node) {
-  Type* outer = ContextType(node);
+  Type* outer = context_type(node);
   return Bounds(Type::Context(outer, zone()));
 }
 
@@ -582,7 +628,7 @@ Bounds Typer::Visitor::TypeJSCallConstruct(Node* node) {
 
 
 Bounds Typer::Visitor::TypeJSCallFunction(Node* node) {
-  Bounds fun = OperandType(node, 0);
+  Bounds fun = operand(node, 0);
   Type* lower = fun.lower->IsFunction()
       ? fun.lower->AsFunction()->Result() : Type::None(zone());
   Type* upper = fun.upper->IsFunction()
@@ -649,7 +695,7 @@ Bounds Typer::Visitor::TypeNumberModulus(Node* node) {
 
 
 Bounds Typer::Visitor::TypeNumberToInt32(Node* node) {
-  Bounds arg = OperandType(node, 0);
+  Bounds arg = operand(node, 0);
   Type* s32 = Type::Signed32(zone());
   Type* lower = arg.lower->Is(s32) ? arg.lower : s32;
   Type* upper = arg.upper->Is(s32) ? arg.upper : s32;
@@ -658,7 +704,7 @@ Bounds Typer::Visitor::TypeNumberToInt32(Node* node) {
 
 
 Bounds Typer::Visitor::TypeNumberToUint32(Node* node) {
-  Bounds arg = OperandType(node, 0);
+  Bounds arg = operand(node, 0);
   Type* u32 = Type::Unsigned32(zone());
   Type* lower = arg.lower->Is(u32) ? arg.lower : u32;
   Type* upper = arg.upper->Is(u32) ? arg.upper : u32;
@@ -749,12 +795,14 @@ Bounds Typer::Visitor::TypeLoadElement(Node* node) {
 
 
 Bounds Typer::Visitor::TypeStoreField(Node* node) {
-  return Bounds(Type::None());
+  UNREACHABLE();
+  return Bounds();
 }
 
 
 Bounds Typer::Visitor::TypeStoreElement(Node* node) {
-  return Bounds(Type::None());
+  UNREACHABLE();
+  return Bounds();
 }
 
 
@@ -831,25 +879,6 @@ Type* Typer::Visitor::TypeConstant(Handle<Object> value) {
   return Type::Constant(value, zone());
 }
 
-
-namespace {
-
-class TyperDecorator : public GraphDecorator {
- public:
-  explicit TyperDecorator(Typer* typer) : typer_(typer) {}
-  virtual void Decorate(Node* node) { typer_->Init(node); }
-
- private:
-  Typer* typer_;
-};
-
-}
-
-
-void Typer::DecorateGraph(Graph* graph) {
-  graph->AddDecorator(new (zone()) TyperDecorator(this));
-}
-
 }
 }
 }  // namespace v8::internal::compiler