X64: Checked and slightly modified Object layouts to be compatible with 64-bit pointers.

X64: Checked and slightly modified Object layouts to be compatible with 64-bit pointers.

[Lasse Reichstein, 2009-05-18 11:28:04]

Review of heap object modifications.

[William Hesse, 2009-05-18 11:41:30]

If garbage collector support for ByteArray and Strings now gets size rounded up
to pointer alignment, are there corresponding changes to the allocators for
ByteArray and Strings?

http://codereview.chromium.org/113522/diff/1/5
File src/objects.h (right):

http://codereview.chromium.org/113522/diff/1/5#newcode2795
Line 2795: static const int kInstanceClassNameOffset =
Are you depending on the fact that you have an even number of integer fields? 
Should you call pointer align macro before adding the ExternalReferenceData
field?

[Erik Corry, 2009-05-18 11:52:11]

LGTM

http://codereview.chromium.org/113522/diff/1/5
File src/objects.h (right):

http://codereview.chromium.org/113522/diff/1/5#newcode3669
Line 3669: // buffer.
Clever.  I suggest the following comment:
Each character represents 32 bits.  M is the map, L is the length/hash, B and S
are the buffer and start in a sliced string.  1 and 2 are the first and second
parts of a cons string.
32 bit Slice: MLBS
32 bit Cons:  ML12
64 bit Slice: MMLSBB
64 bit Cons:  MML 1122

http://codereview.chromium.org/113522/diff/1/5#newcode4167
Line 4167: static const int kSize = kInternalFieldCountOffset + kPointerSize;
Good catch.

[Lasse Reichstein, 2009-05-18 12:08:23]

There is no X64 support for garbage collection yet. There is no change in layout
for strings and byte arrays in 32-bit mode.

http://codereview.chromium.org/113522/diff/1/5
File src/objects.h (right):

http://codereview.chromium.org/113522/diff/1/5#newcode2795
Line 2795: static const int kInstanceClassNameOffset =
I am relying on that, but I think documentation should be enough.

http://codereview.chromium.org/113522/diff/1/5#newcode3669
Line 3669: // buffer.
On 2009/05/18 11:52:11, Erik Corry wrote:
> Clever.  I suggest the following comment:
> Each character represents 32 bits.  M is the map, L is the length/hash, B and
S
> are the buffer and start in a sliced string.  1 and 2 are the first and
second
> parts of a cons string.
> 32 bit Slice: MLBS
> 32 bit Cons:  ML12
> 64 bit Slice: MMLSBB
> 64 bit Cons:  MML 1122  

Done.

[Lasse Reichstein, 2009-05-18 12:08:26]

There is no X64 support for garbage collection yet. There is no change in layout
for strings and byte arrays in 32-bit mode.