Endian changes, support 64bit big endian

src/objects.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_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include "src/allocation.h"
 #include "src/assert-scope.h"
 #include "src/base/bits.h"
@@ skipping 3150 matching lines @@
 
   // Fields in kSmallLayout2Offset.
   class Int32CountField: public BitField<int, 1, kSmallLayoutCountBits> {};
   class TotalCountField: public BitField<int, 11, 12> {};
   class WeakObjectStateField: public BitField<WeakObjectState, 23, 2> {};
 
   // Extended layout description, which starts at
   // get_extended_section_header_offset().
   static const int kExtendedInt64CountOffset = 0;
   static const int kExtendedCodePtrCountOffset =
-      kExtendedInt64CountOffset + kPointerSize;
+      kExtendedInt64CountOffset + kInt32Size;

[Sven Panne, 2014/09/16 10:48:40]

I think that this is wrong: We access this via READ_INT_FIELD/WRITE_INT_FIELD,
and they use *int*, not *int32_t*. Same for the rest. kPointerSize was wrong,
too, BTW...

@Ross: What do you think? Somehow the accessors have to match these constants.

[rmcilroy, 2014/09/18 10:54:44]

Yeah I agree - Andrew - could you change the accessors to use
READ/WRITE_INT32_FIELD as well please.

[andrew_low, 2014/09/22 17:49:18]

Done.

   static const int kExtendedHeapPtrCountOffset =
-      kExtendedCodePtrCountOffset + kPointerSize;
+      kExtendedCodePtrCountOffset + kInt32Size;
   static const int kExtendedInt32CountOffset =
-      kExtendedHeapPtrCountOffset + kPointerSize;
+      kExtendedHeapPtrCountOffset + kInt32Size;
   static const int kExtendedFirstOffset =
-      kExtendedInt32CountOffset + kPointerSize;
+      kExtendedInt32CountOffset + kInt32Size;
 
   // Dispatched behavior.
   void ConstantPoolIterateBody(ObjectVisitor* v);
 
   DECLARE_PRINTER(ConstantPoolArray)
   DECLARE_VERIFIER(ConstantPoolArray)
 
  private:
   inline int first_extended_section_index();
   inline int get_extended_section_header_offset();
@@ skipping 2487 matching lines @@
   static const int kICAgeOffset =
       kGCMetadataOffset + kPointerSize;
   static const int kFlagsOffset = kICAgeOffset + kIntSize;
   static const int kKindSpecificFlags1Offset = kFlagsOffset + kIntSize;
   static const int kKindSpecificFlags2Offset =
       kKindSpecificFlags1Offset + kIntSize;
   // Note: We might be able to squeeze this into the flags above.
   static const int kPrologueOffset = kKindSpecificFlags2Offset + kIntSize;
   static const int kConstantPoolOffset = kPrologueOffset + kPointerSize;
 
-  static const int kHeaderPaddingStart = kConstantPoolOffset + kIntSize;
+  static const int kHeaderPaddingStart = kConstantPoolOffset + kPointerSize;
 
   // Add padding to align the instruction start following right after
   // the Code object header.
   static const int kHeaderSize =
       (kHeaderPaddingStart + kCodeAlignmentMask) & ~kCodeAlignmentMask;
 
   // Byte offsets within kKindSpecificFlags1Offset.
   static const int kOptimizableOffset = kKindSpecificFlags1Offset;
 
   static const int kFullCodeFlags = kOptimizableOffset + 1;
@@ skipping 1549 matching lines @@
       kAstNodeCountOffset + kPointerSize;
 
   // Total size.
   static const int kSize = kProfilerTicksOffset + kPointerSize;
 #else
   // The only reason to use smi fields instead of int fields
   // is to allow iteration without maps decoding during
   // garbage collections.
   // To avoid wasting space on 64-bit architectures we use
   // the following trick: we group integer fields into pairs
-  // First integer in each pair is shifted left by 1.
-  // By doing this we guarantee that LSB of each kPointerSize aligned
-  // word is not set and thus this word cannot be treated as pointer
-  // to HeapObject during old space traversal.
+// The least significant integer in each pair is shifted left by 1.
+// By doing this we guarantee that LSB of each kPointerSize aligned
+// word is not set and thus this word cannot be treated as pointer
+// to HeapObject during old space traversal.
+#if V8_TARGET_LITTLE_ENDIAN
   static const int kLengthOffset =
       kFeedbackVectorOffset + kPointerSize;
   static const int kFormalParameterCountOffset =
       kLengthOffset + kIntSize;
 
   static const int kExpectedNofPropertiesOffset =
       kFormalParameterCountOffset + kIntSize;
   static const int kNumLiteralsOffset =
       kExpectedNofPropertiesOffset + kIntSize;
 
@@ skipping 13 matching lines @@
       kOptCountAndBailoutReasonOffset + kIntSize;
 
   static const int kAstNodeCountOffset =
       kCountersOffset + kIntSize;
   static const int kProfilerTicksOffset =
       kAstNodeCountOffset + kIntSize;
 
   // Total size.
   static const int kSize = kProfilerTicksOffset + kIntSize;
 
-#endif
+#elif V8_TARGET_BIG_ENDIAN

[Sven Panne, 2014/09/16 10:48:40]

This is very fragile: At least we have to cross-reference these constants with
the (PSEUDO_)SMI_ACCESOR stuff in objects-inl.h, in both directions.

(What we *really* need is some kind of DSL describing our object layouts, this
is getting really ugly...)

[andrew_low, 2014/09/22 17:49:18]

It's not clear what you're suggesting should be done here.

+  static const int kFormalParameterCountOffset =
+      kFeedbackVectorOffset + kPointerSize;
+  static const int kLengthOffset = kFormalParameterCountOffset + kIntSize;
+
+  static const int kNumLiteralsOffset = kLengthOffset + kIntSize;
+  static const int kExpectedNofPropertiesOffset = kNumLiteralsOffset + kIntSize;
+
+  static const int kStartPositionAndTypeOffset =
+      kExpectedNofPropertiesOffset + kIntSize;
+  static const int kEndPositionOffset = kStartPositionAndTypeOffset + kIntSize;
+
+  static const int kCompilerHintsOffset = kEndPositionOffset + kIntSize;
+  static const int kFunctionTokenPositionOffset =
+      kCompilerHintsOffset + kIntSize;
+
+  static const int kCountersOffset = kFunctionTokenPositionOffset + kIntSize;
+  static const int kOptCountAndBailoutReasonOffset = kCountersOffset + kIntSize;
+
+  static const int kProfilerTicksOffset =
+      kOptCountAndBailoutReasonOffset + kIntSize;
+  static const int kAstNodeCountOffset = kProfilerTicksOffset + kIntSize;
+
+  // Total size.
+  static const int kSize = kAstNodeCountOffset + kIntSize;
+
+#else
+#error Unknown byte ordering
+#endif  // Big endian
+#endif  // 64-bit
+
 
   static const int kAlignedSize = POINTER_SIZE_ALIGN(kSize);
 
   typedef FixedBodyDescriptor<kNameOffset,
                               kFeedbackVectorOffset + kPointerSize,
                               kSize> BodyDescriptor;
 
   // Bit positions in start_position_and_type.
   // The source code start position is in the 30 most significant bits of
   // the start_position_and_type field.
@@ skipping 1502 matching lines @@
   inline bool AsArrayIndex(uint32_t* index);
 
   // Whether name can only name own properties.
   inline bool IsOwn();
 
   DECLARE_CAST(Name)
 
   DECLARE_PRINTER(Name)
 
   // Layout description.
-  static const int kHashFieldOffset = HeapObject::kHeaderSize;
-  static const int kSize = kHashFieldOffset + kPointerSize;
+  static const int kHashFieldSlot = HeapObject::kHeaderSize;
+#if V8_TARGET_LITTLE_ENDIAN || !V8_HOST_ARCH_64_BIT
+  static const int kHashFieldOffset = kHashFieldSlot;
+#else
+  static const int kHashFieldOffset = kHashFieldSlot + kIntSize;
+#endif
+  static const int kSize = kHashFieldSlot + kPointerSize;
 
   // Mask constant for checking if a name has a computed hash code
   // and if it is a string that is an array index.  The least significant bit
   // indicates whether a hash code has been computed.  If the hash code has
   // been computed the 2nd bit tells whether the string can be used as an
   // array index.
   static const int kHashNotComputedMask = 1;
   static const int kIsNotArrayIndexMask = 1 << 1;
   static const int kNofHashBitFields = 2;
 
@@ skipping 2308 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_