Optimize testing for an index's existence in packed Arrays

src/runtime/runtime.h

 // 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.
 
 #ifndef V8_RUNTIME_RUNTIME_H_
 #define V8_RUNTIME_RUNTIME_H_
 
 #include "src/allocation.h"
 #include "src/objects.h"
 #include "src/zone.h"
@@ skipping 686 matching lines @@
   F(DebugBreakInOptimizedCode, 0, 1)                        \
   F(ClassOf, 1, 1)                                          \
   F(StringCharCodeAt, 2, 1)                                 \
   F(StringAdd, 2, 1)                                        \
   F(SubString, 3, 1)                                        \
   F(StringCompare, 2, 1)                                    \
   F(RegExpExec, 4, 1)                                       \
   F(RegExpConstructResult, 3, 1)                            \
   F(GetFromCache, 2, 1)                                     \
   F(NumberToString, 1, 1)                                   \
-  F(DebugIsActive, 0, 1)
+  F(DebugIsActive, 0, 1)                                    \
+  F(HasFastPackedElements, 1, 1)

[Dmitry Lomov (no reviews), 2014/11/27 07:17:54]

Is it critical for HasFastPackedElements to be INLINE_FUNCTION instead of
INLINE_OPTIMIZED_FUNCTION (see below, line 718)? 
If you use runtime function in full codegen, you will save yourself from having
to write all those tedious Emit functions in all the ports

[adamk, 2014/12/02 19:36:20]

Not sure what counts as "critical". Sure, the implementations are a bit tedious,
but they're straightforward enough, so I don't see much point in penalizing full
codegen if I can make them fast.

 
 
 // ----------------------------------------------------------------------------
 // INLINE_OPTIMIZED_FUNCTION_LIST defines all inlined functions accessed
 // with a native call of the form %_name from within JS code that also have
 // a corresponding runtime function, that is called from non-optimized code.
 // For the benefit of (fuzz) tests, the runtime version can also be called
 // directly as %name (i.e. without the leading underscore).
 // Entries have the form F(name, number of arguments, number of return values).
 #define INLINE_OPTIMIZED_FUNCTION_LIST(F) \
@@ skipping 171 matching lines @@
 class AllocateTargetSpace : public BitField<AllocationSpace, 1, 3> {};
 
 class DeclareGlobalsEvalFlag : public BitField<bool, 0, 1> {};
 class DeclareGlobalsNativeFlag : public BitField<bool, 1, 1> {};
 class DeclareGlobalsStrictMode : public BitField<StrictMode, 2, 1> {};
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_RUNTIME_RUNTIME_H_