Reland [heap] Avoid the use of cells to point from code to new-space objects.

Reland [heap] Avoid the use of cells to point from code to new-space objects.

The reason for reverting is: This breaks gc-stress bot:
https://chromegw.corp.google.com/i/client.v8/builders/V8%20Linux64%20GC%20Stress%20-%20custom%20snapshot

Abortion of compaction could cause duplicate entries in the typed-old-to-new remembered set. These duplicates could cause a DCHECK to trigger which checks that slots recorded in the remembered set never point to to-space. This reland-CL allows duplicates in the remembered set by removing the DCHECK, and additionally clears entries in the remembered set if objects are moved.

Original issue's description:

Cells were needed originally because there was no typed remembered set to
record direct pointers from code space to new space. A previous
CL (https://codereview.chromium.org/2003553002/) already introduced
the remembered set, this CL uses it.

This CL
* stores direct pointers in code objects, even if the target is in new space,
* records the slot of the pointer in typed-old-to-new remembered set,
* adds a list which stores weak code-to-new-space references,
* adds a test to test-heap.cc for weak code-to-new-space references,
* removes prints in tail-call-megatest.js

Committed: https://crrev.com/5e058540192eaf95e8d1c2c3d0920219491cde15
Cr-Commit-Position: refs/heads/master@{#37325}

[ahaas, 2016-06-28 11:35:37]

Description was changed from

==========
Reland [heap] Avoid the use of cells to point from code to new-space objects.

The reason for reverting was: [Sheriff] Breaks arm debug:
https://build.chromium.org/p/client.v8.ports/builders/V8%20Linux%20-%20arm%20....

The problem was the dereferencing of handles for smi checks. It turned out
that these smi checks can be removed anyways, both on arm and on mips.

Additionally some rebasing was necessary.

Original issue's description:

Cells were needed originally because there was no typed remembered set to
record direct pointers from code space to new space. A previous
CL (https://codereview.chromium.org/2003553002/) already introduced
the remembered set, this CL uses it.

This CL
* stores direct pointers in code objects, even if the target is in new space,
* records the slot of the pointer in typed-old-to-new remembered set,
* adds a list which stores weak code-to-new-space references,
* adds a test to test-heap.cc for weak code-to-new-space references,
* removes prints in tail-call-megatest.js
==========

to

==========
Reland [heap] Avoid the use of cells to point from code to new-space objects.

The reason for reverting is: This breaks gc-stress bot:
https://chromegw.corp.google.com/i/client.v8/builders/V8%20Linux64%20GC%20Str...

Abortion of compaction could cause duplicate entries in the typed-old-to-new
remembered set. These duplicates could cause a DCHECK to trigger which checks
that slots recorded in the remembered set never point to to-space. This
reland-CL allows duplicates in the remembered set by removing the DCHECK, and
additionally clears entries in the remembered set if objects are moved.

Original issue's description:

Cells were needed originally because there was no typed remembered set to
record direct pointers from code space to new space. A previous
CL (https://codereview.chromium.org/2003553002/) already introduced
the remembered set, this CL uses it.

This CL
* stores direct pointers in code objects, even if the target is in new space,
* records the slot of the pointer in typed-old-to-new remembered set,
* adds a list which stores weak code-to-new-space references,
* adds a test to test-heap.cc for weak code-to-new-space references,
* removes prints in tail-call-megatest.js
==========

[ahaas, 2016-06-28 11:35:37]

ahaas@chromium.org changed reviewers:
+ ulan@chromium.org

[ulan, 2016-06-28 12:10:03]

lgtm

[ahaas, 2016-06-28 12:30:32]

The CQ bit was checked by ahaas@chromium.org

[commit-bot: I haz the power, 2016-06-28 12:30:40]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-06-28 12:34:33]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-06-28 12:36:41]

Description was changed from

==========
Reland [heap] Avoid the use of cells to point from code to new-space objects.

The reason for reverting is: This breaks gc-stress bot:
https://chromegw.corp.google.com/i/client.v8/builders/V8%20Linux64%20GC%20Str...

Abortion of compaction could cause duplicate entries in the typed-old-to-new
remembered set. These duplicates could cause a DCHECK to trigger which checks
that slots recorded in the remembered set never point to to-space. This
reland-CL allows duplicates in the remembered set by removing the DCHECK, and
additionally clears entries in the remembered set if objects are moved.

Original issue's description:

Cells were needed originally because there was no typed remembered set to
record direct pointers from code space to new space. A previous
CL (https://codereview.chromium.org/2003553002/) already introduced
the remembered set, this CL uses it.

This CL
* stores direct pointers in code objects, even if the target is in new space,
* records the slot of the pointer in typed-old-to-new remembered set,
* adds a list which stores weak code-to-new-space references,
* adds a test to test-heap.cc for weak code-to-new-space references,
* removes prints in tail-call-megatest.js
==========

to

==========
Reland [heap] Avoid the use of cells to point from code to new-space objects.

The reason for reverting is: This breaks gc-stress bot:
https://chromegw.corp.google.com/i/client.v8/builders/V8%20Linux64%20GC%20Str...

Abortion of compaction could cause duplicate entries in the typed-old-to-new
remembered set. These duplicates could cause a DCHECK to trigger which checks
that slots recorded in the remembered set never point to to-space. This
reland-CL allows duplicates in the remembered set by removing the DCHECK, and
additionally clears entries in the remembered set if objects are moved.

Original issue's description:

Cells were needed originally because there was no typed remembered set to
record direct pointers from code space to new space. A previous
CL (https://codereview.chromium.org/2003553002/) already introduced
the remembered set, this CL uses it.

This CL
* stores direct pointers in code objects, even if the target is in new space,
* records the slot of the pointer in typed-old-to-new remembered set,
* adds a list which stores weak code-to-new-space references,
* adds a test to test-heap.cc for weak code-to-new-space references,
* removes prints in tail-call-megatest.js

Committed: https://crrev.com/5e058540192eaf95e8d1c2c3d0920219491cde15
Cr-Commit-Position: refs/heads/master@{#37325}
==========

[commit-bot: I haz the power, 2016-06-28 12:36:42]

Patchset 3 (id:??) landed as
https://crrev.com/5e058540192eaf95e8d1c2c3d0920219491cde15
Cr-Commit-Position: refs/heads/master@{#37325}