Collect type feedback on result of Math.[round|ceil|floor]

src/type-info.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/ast.h"
 #include "src/code-stubs.h"
 #include "src/compiler.h"
 #include "src/ic/ic.h"
@@ skipping 124 matching lines @@
              TypeFeedbackVector::UninitializedSentinel(isolate()));
 }
 
 
 bool TypeFeedbackOracle::CallIsMonomorphic(FeedbackVectorICSlot slot) {
   Handle<Object> value = GetInfo(slot);
   return value->IsAllocationSite() || value->IsJSFunction();
 }
 
 
+bool TypeFeedbackOracle::CallIsBuiltinWithMinusZeroResult(
+    FeedbackVectorICSlot slot) {
+  Handle<Object> value = GetInfo(slot);
+  if (!value->IsJSFunction()) return false;
+  Handle<JSFunction> maybe_round(Handle<JSFunction>::cast(value));
+  SmartArrayPointer<char> n = maybe_round->shared()->DebugName()->ToCString();

[mvstanton, 2015/05/04 09:41:22]

You don't need n here.

[danno, 2015/05/04 14:31:56]

Done.

+  if (!maybe_round->shared()->HasBuiltinFunctionId()) return false;
+  if (maybe_round->shared()->builtin_function_id() != kMathRound &&
+      maybe_round->shared()->builtin_function_id() != kMathFloor &&
+      maybe_round->shared()->builtin_function_id() != kMathCeil) {
+    return false;
+  }
+  return feedback_vector_->get(feedback_vector_->GetIndex(slot) + 1) ==
+         Smi::FromInt(CallICStub::kHasReturnedMinusZeroSentinel);
+}
+
+
 bool TypeFeedbackOracle::CallNewIsMonomorphic(FeedbackVectorSlot slot) {
   Handle<Object> info = GetInfo(slot);
   return FLAG_pretenuring_call_new
       ? info->IsJSFunction()
       : info->IsAllocationSite() || info->IsJSFunction();
 }
 
 
 byte TypeFeedbackOracle::ForInType(FeedbackVectorSlot feedback_vector_slot) {
   Handle<Object> value = GetInfo(feedback_vector_slot);
@@ skipping 379 matching lines @@
          UnseededNumberDictionary::kNotFound);
   // Dictionary has been allocated with sufficient size for all elements.
   DisallowHeapAllocation no_need_to_resize_dictionary;
   HandleScope scope(isolate());
   USE(UnseededNumberDictionary::AtNumberPut(
       dictionary_, IdToKey(ast_id), handle(target, isolate())));
 }
 
 
 } }  // namespace v8::internal