Contribution of PowerPC port.

src/frames.h

Index: src/frames.h
diff --git a/src/frames.h b/src/frames.h
index a39d90fd956734a9ddd9b1922259175117e39d4e..dbc1e577f8c42d9b927a61988f4365c37bb82c4a 100644
--- a/src/frames.h
+++ b/src/frames.h
@@ -71,6 +71,11 @@ class StackHandlerConstants : public AllStatic {
   static const int kNextOffset     = 0 * kPointerSize;
   static const int kCodeOffset     = 1 * kPointerSize;
   static const int kStateOffset    = 2 * kPointerSize;
+#if V8_TARGET_LITTLE_ENDIAN || !V8_HOST_ARCH_64_BIT
+  static const int kStateIntOffset = kStateOffset;

[danno, 2014/07/29 13:24:08]

If kStateOffset isn't used for anything else but kStateIntOffset, then simply
remove it.

Perhaps it makes sense to put a constant kLowWordOfIntOffset in v8.h or
somewhere common that is keyed off of V8_TARGET_LITTLE_ENDIAN ||
!V8_HOST_ARCH_64_BIT, and then this can simply be

static const int kStateOffset = 2 * kPointerSize + kLowWordOfIntOffset;

[andrew_low, 2014/07/30 13:27:05]

Both kStateOffset and kStateIntOffset are used is a handful of places. I agree
with your comment about kLowWordOfIntOffset - but would like more guidance
before I start down that path.

$ grep kStateOffset *
frames.cc:  Memory::uintptr_at(address() + StackHandlerConstants::kStateOffset)
= state;
frames.h:  static const int kStateOffset    = 2 * kPointerSize;
frames.h:  static const int kStateIntOffset = kStateOffset;
frames.h:  static const int kStateIntOffset = kStateOffset + kIntSize;

$ grep kStateIntOffset *
frames.h:  static const int kStateIntOffset = kStateOffset;
frames.h:  static const int kStateIntOffset = kStateOffset + kIntSize;
frames-inl.h:  const int offset = StackHandlerConstants::kStateIntOffset;
frames-inl.h:  const int offset = StackHandlerConstants::kStateIntOffset;

+#else
+  static const int kStateIntOffset = kStateOffset + kIntSize;
+#endif
   static const int kContextOffset  = 3 * kPointerSize;
   static const int kFPOffset       = 4 * kPointerSize;