Move feedback slot allocation to post-pass

src/compiler.cc

 // Copyright 2012 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/v8.h"
 
 #include "src/compiler.h"
 
 #include "src/ast-numbering.h"
 #include "src/bootstrapper.h"
@@ skipping 273 matching lines @@
       !function()->flags()->Contains(kDontSelfOptimize) &&
       !function()->dont_optimize() &&
       function()->scope()->AllowsLazyCompilation() &&
       (shared_info().is_null() || !shared_info()->optimization_disabled());
 }
 
 
 void CompilationInfo::PrepareForCompilation(Scope* scope) {
   DCHECK(scope_ == NULL);
   scope_ = scope;
+}
 
+
+void CompilationInfo::EnsureFeedbackVector() {
   if (feedback_vector_.is_null()) {
-    // Allocate the feedback vector too.
     feedback_vector_ = isolate()->factory()->NewTypeFeedbackVector(
         function()->slot_count(), function()->ic_slot_count());
   }
   DCHECK(feedback_vector_->Slots() == function()->slot_count() &&
          feedback_vector_->ICSlots() == function()->ic_slot_count());
 }
 
 
 class HOptimizedGraphBuilderWithPositions: public HOptimizedGraphBuilder {
  public:
@@ skipping 1011 matching lines @@
     // Make sure that if the toplevel code (possibly to be serialized),
     // the inner function must be allowed to be compiled lazily.
     DCHECK(allow_lazy);
   }
 
   // Generate code
   Handle<ScopeInfo> scope_info;
   if (FLAG_lazy && allow_lazy && !literal->is_parenthesized()) {
     Handle<Code> code = isolate->builtins()->CompileLazy();
     info.SetCode(code);
+    // There's no need in theory for a lazy-compiled function to have a type
+    // feedback vector, but some parts of the system expect all
+    // SharedFunctionInfo instances to have one.  The size of the vector depends
+    // on how many feedback-needing nodes are in the tree, and when lazily
+    // parsing we might not know that, if this function was never parsed before.
+    // In that case the vector will be replaced the next time MakeCode is
+    // called.
+    info.EnsureFeedbackVector();
     scope_info = Handle<ScopeInfo>(ScopeInfo::Empty(isolate));
   } else if (Renumber(&info) && FullCodeGenerator::MakeCode(&info)) {
+    // MakeCode will ensure that the feedback vector is present and
+    // appropriately sized.
     DCHECK(!info.code().is_null());
     scope_info = ScopeInfo::Create(info.scope(), info.zone());
   } else {
     return Handle<SharedFunctionInfo>::null();
   }
 
   // Create a shared function info object.
   Handle<SharedFunctionInfo> result = factory->NewSharedFunctionInfo(
       literal->name(), literal->materialized_literal_count(), literal->kind(),
       info.code(), scope_info, info.feedback_vector());
@@ skipping 141 matching lines @@
   AllowHandleDereference allow_deref;
   bool tracing_on = info()->IsStub()
       ? FLAG_trace_hydrogen_stubs
       : (FLAG_trace_hydrogen &&
          info()->closure()->PassesFilter(FLAG_trace_hydrogen_filter));
   return (tracing_on &&
       base::OS::StrChr(const_cast<char*>(FLAG_trace_phase), name_[0]) != NULL);
 }
 
 } }  // namespace v8::internal