Make use of post-scoping information to compute feedback vector requirements.

This avoids allocating vector ic slots that we don't use.

R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/758543002

Cr-Commit-Position: refs/heads/master@{#25485}

src/ast-numbering.cc

@@ -66,7 +66,8 @@ class AstNumberingVisitor FINAL : public AstVisitor {
 
   template <typename Node>
   void ReserveFeedbackSlots(Node* node) {
-    FeedbackVectorRequirements reqs = node->ComputeFeedbackRequirements();
+    FeedbackVectorRequirements reqs =
+        node->ComputeFeedbackRequirements(isolate());
     if (reqs.slots() > 0) {
       node->SetFirstFeedbackSlot(
           FeedbackVectorSlot(properties_.feedback_slots()));

src/ast.cc

@@ -573,6 +573,12 @@ bool Call::IsUsingCallFeedbackSlot(Isolate* isolate) const {
 }
 
 
+FeedbackVectorRequirements Call::ComputeFeedbackRequirements(Isolate* isolate) {
+  int ic_slots = IsUsingCallFeedbackSlot(isolate) ? 1 : 0;
+  return FeedbackVectorRequirements(0, ic_slots);
+}
+
+
 Call::CallType Call::GetCallType(Isolate* isolate) const {
   VariableProxy* proxy = expression()->AsVariableProxy();
   if (proxy != NULL) {

src/ast.h

@@ -237,7 +237,8 @@ class AstNode: public ZoneObject {
   // node types which don't actually have this. Note that this is conceptually
   // not really nice, but multiple inheritance would introduce yet another
   // vtable entry per node, something we don't want for space reasons.
-  virtual FeedbackVectorRequirements ComputeFeedbackRequirements() {
+  virtual FeedbackVectorRequirements ComputeFeedbackRequirements(
+      Isolate* isolate) {
     return FeedbackVectorRequirements(0, 0);
   }
   virtual void SetFirstFeedbackSlot(FeedbackVectorSlot slot) { UNREACHABLE(); }
@@ -923,7 +924,8 @@ class ForInStatement FINAL : public ForEachStatement {
   }
 
   // Type feedback information.
-  virtual FeedbackVectorRequirements ComputeFeedbackRequirements() OVERRIDE {
+  virtual FeedbackVectorRequirements ComputeFeedbackRequirements(
+      Isolate* isolate) OVERRIDE {
     return FeedbackVectorRequirements(1, 0);
   }
   virtual void SetFirstFeedbackSlot(FeedbackVectorSlot slot) OVERRIDE {
@@ -1696,7 +1698,8 @@ class VariableProxy FINAL : public Expression {
   // Bind this proxy to the variable var. Interfaces must match.
   void BindTo(Variable* var);
 
-  virtual FeedbackVectorRequirements ComputeFeedbackRequirements() OVERRIDE {
+  virtual FeedbackVectorRequirements ComputeFeedbackRequirements(
+      Isolate* isolate) OVERRIDE {
     return FeedbackVectorRequirements(0, FLAG_vector_ics ? 1 : 0);
   }
   virtual void SetFirstFeedbackICSlot(FeedbackVectorICSlot slot) OVERRIDE {
@@ -1782,7 +1785,8 @@ class Property FINAL : public Expression {
     return obj()->IsSuperReference();
   }
 
-  virtual FeedbackVectorRequirements ComputeFeedbackRequirements() OVERRIDE {
+  virtual FeedbackVectorRequirements ComputeFeedbackRequirements(
+      Isolate* isolate) OVERRIDE {
     return FeedbackVectorRequirements(0, FLAG_vector_ics ? 1 : 0);
   }
   virtual void SetFirstFeedbackICSlot(FeedbackVectorICSlot slot) OVERRIDE {
@@ -1827,9 +1831,8 @@ class Call FINAL : public Expression {
   ZoneList<Expression*>* arguments() const { return arguments_; }
 
   // Type feedback information.
-  virtual FeedbackVectorRequirements ComputeFeedbackRequirements() OVERRIDE {
-    return FeedbackVectorRequirements(0, 1);
-  }
+  virtual FeedbackVectorRequirements ComputeFeedbackRequirements(
+      Isolate* isolate) OVERRIDE;
   virtual void SetFirstFeedbackICSlot(FeedbackVectorICSlot slot) OVERRIDE {
     call_feedback_slot_ = slot;
   }
@@ -1940,7 +1943,8 @@ class CallNew FINAL : public Expression {
   ZoneList<Expression*>* arguments() const { return arguments_; }
 
   // Type feedback information.
-  virtual FeedbackVectorRequirements ComputeFeedbackRequirements() OVERRIDE {
+  virtual FeedbackVectorRequirements ComputeFeedbackRequirements(
+      Isolate* isolate) OVERRIDE {
     return FeedbackVectorRequirements(FLAG_pretenuring_call_new ? 2 : 1, 0);
   }
   virtual void SetFirstFeedbackSlot(FeedbackVectorSlot slot) OVERRIDE {
@@ -2005,7 +2009,8 @@ class CallRuntime FINAL : public Expression {
   bool is_jsruntime() const { return function_ == NULL; }
 
   // Type feedback information.
-  virtual FeedbackVectorRequirements ComputeFeedbackRequirements() OVERRIDE {
+  virtual FeedbackVectorRequirements ComputeFeedbackRequirements(
+      Isolate* isolate) OVERRIDE {
     return FeedbackVectorRequirements(
         0, (FLAG_vector_ics && is_jsruntime()) ? 1 : 0);
   }
@@ -2384,7 +2389,8 @@ class Yield FINAL : public Expression {
   }
 
   // Type feedback information.
-  virtual FeedbackVectorRequirements ComputeFeedbackRequirements() OVERRIDE {
+  virtual FeedbackVectorRequirements ComputeFeedbackRequirements(
+      Isolate* isolate) OVERRIDE {
     return FeedbackVectorRequirements(
         0, (FLAG_vector_ics && yield_kind() == kDelegating) ? 3 : 0);
   }
@@ -2721,7 +2727,8 @@ class SuperReference FINAL : public Expression {
   TypeFeedbackId HomeObjectFeedbackId() { return TypeFeedbackId(local_id(0)); }
 
   // Type feedback information.
-  virtual FeedbackVectorRequirements ComputeFeedbackRequirements() OVERRIDE {
+  virtual FeedbackVectorRequirements ComputeFeedbackRequirements(
+      Isolate* isolate) OVERRIDE {
     return FeedbackVectorRequirements(0, FLAG_vector_ics ? 1 : 0);
   }
   virtual void SetFirstFeedbackICSlot(FeedbackVectorICSlot slot) OVERRIDE {

src/typing.cc

@@ -510,16 +510,20 @@ void AstTyper::VisitProperty(Property* expr) {
 void AstTyper::VisitCall(Call* expr) {
   // Collect type feedback.
   RECURSE(Visit(expr->expression()));
-  FeedbackVectorICSlot slot = expr->CallFeedbackSlot();
-  expr->set_is_uninitialized(oracle()->CallIsUninitialized(slot));
-  if (!expr->expression()->IsProperty() &&
-      expr->IsUsingCallFeedbackSlot(isolate()) &&
-      oracle()->CallIsMonomorphic(slot)) {
-    expr->set_target(oracle()->GetCallTarget(slot));
-    Handle<AllocationSite> site = oracle()->GetCallAllocationSite(slot);
-    expr->set_allocation_site(site);
+  bool is_uninitialized = true;
+  if (expr->IsUsingCallFeedbackSlot(isolate())) {
+    FeedbackVectorICSlot slot = expr->CallFeedbackSlot();
+    is_uninitialized = oracle()->CallIsUninitialized(slot);
+    if (!expr->expression()->IsProperty() &&
+        oracle()->CallIsMonomorphic(slot)) {
+      expr->set_target(oracle()->GetCallTarget(slot));
+      Handle<AllocationSite> site = oracle()->GetCallAllocationSite(slot);
+      expr->set_allocation_site(site);
+    }
   }
 
+  expr->set_is_uninitialized(is_uninitialized);
+
   ZoneList<Expression*>* args = expr->arguments();
   for (int i = 0; i < args->length(); ++i) {
     Expression* arg = args->at(i);