X64: Add a jumptable to for deoptimization checks on X64....

X64: Add a jumptable to for deoptimization checks on X64.

The current version includes an extra jump compared to IA32, because
we need to load the jump address into a register and do an indirect
jump, but in the normal case we just jump over this by negating the
deoptimization conditional.


Committed: http://code.google.com/p/v8/source/detail?r=6972

[Lasse Reichstein, 2011-02-28 08:42:30]

LGTM

http://codereview.chromium.org/6596032/diff/1/src/x64/lithium-codegen-x64.cc
File src/x64/lithium-codegen-x64.cc (right):

http://codereview.chromium.org/6596032/diff/1/src/x64/lithium-codegen-x64.cc#...
src/x64/lithium-codegen-x64.cc:526: JumpTableEntry* jump_info = new
JumpTableEntry();
Can we generate the same jump more than once? (I.e., is there anything to save
by recognizing it and making only one entry in the jump-table).

http://codereview.chromium.org/6596032/diff/1/src/x64/lithium-codegen-x64.cc#...
src/x64/lithium-codegen-x64.cc:527: jump_info->address = entry;
Set this in a constructor.

http://codereview.chromium.org/6596032/diff/1/src/x64/lithium-codegen-x64.h
File src/x64/lithium-codegen-x64.h (right):

http://codereview.chromium.org/6596032/diff/1/src/x64/lithium-codegen-x64.h#n...
src/x64/lithium-codegen-x64.h:56: jump_table_(4),
If possible, remove the 4 (and the 4 above). Just rely on the ZoneList default
initial capacity (which, IIRC, happens to be 4).

http://codereview.chromium.org/6596032/diff/1/src/x64/lithium-codegen-x64.h#n...
src/x64/lithium-codegen-x64.h:239: struct JumpTableEntry {
Have a constructor to initialize label and address.

[Rico, 2011-02-28 09:57:12]

Comments addressed, please take another look

http://codereview.chromium.org/6596032/diff/1/src/x64/lithium-codegen-x64.cc
File src/x64/lithium-codegen-x64.cc (right):

http://codereview.chromium.org/6596032/diff/1/src/x64/lithium-codegen-x64.cc#...
src/x64/lithium-codegen-x64.cc:526: JumpTableEntry* jump_info = new
JumpTableEntry();
On 2011/02/28 08:42:30, Lasse Reichstein wrote:
> Can we generate the same jump more than once? (I.e., is there anything to save
> by recognizing it and making only one entry in the jump-table).

Done.

http://codereview.chromium.org/6596032/diff/1/src/x64/lithium-codegen-x64.cc#...
src/x64/lithium-codegen-x64.cc:527: jump_info->address = entry;
On 2011/02/28 08:42:30, Lasse Reichstein wrote:
> Set this in a constructor.

Done.

http://codereview.chromium.org/6596032/diff/1/src/x64/lithium-codegen-x64.h
File src/x64/lithium-codegen-x64.h (right):

http://codereview.chromium.org/6596032/diff/1/src/x64/lithium-codegen-x64.h#n...
src/x64/lithium-codegen-x64.h:56: jump_table_(4),
On 2011/02/28 08:42:30, Lasse Reichstein wrote:
> If possible, remove the 4 (and the 4 above). Just rely on the ZoneList default
> initial capacity (which, IIRC, happens to be 4).
There is no default ZoneList constructor

http://codereview.chromium.org/6596032/diff/1/src/x64/lithium-codegen-x64.h#n...
src/x64/lithium-codegen-x64.h:239: struct JumpTableEntry {
On 2011/02/28 08:42:30, Lasse Reichstein wrote:
> Have a constructor to initialize label and address.

Done.

[Lasse Reichstein, 2011-02-28 13:56:30]

LGTM too.