[date] Refactor TimezoneCache to be separate from the OS

[date] Refactor TimezoneCache to be separate from the OS

This refactoring is preparatory work to enable ICU to be the backend
for timezone information rather than system calls. In the process, a
bit of code duplication that was inserted in the Solaris port patch is
eliminated here among modern POSIX backends.

One possible performance downside of this patch is that it introduces
a virtual method call for operations which were previously not virtual
methods. However, a couple factors mitigate this effect:
- The DateCache minimizes the need for calls into the TimezoneCache
- These calls were already not very high performance, as they included
  a system call which requires an RPC to get out of the sandbox, and
  they are surrounded by C++ builtins, which require a JS to C++
  transition.
- A future transition to ICU, enabled by this refactoring, may improve
  performance by eliminating the system call.

BUG=v8:6031
Review-Url: https://codereview.chromium.org/2731463003
Cr-Commit-Position: refs/heads/master@{#43588}
Committed: https://chromium.googlesource.com/v8/v8/+/ccfe50b95ae78c9b59d57ba47a734d63a3acb4f6

[Dan Ehrenberg, 2017-03-02 10:16:57]

Description was changed from

==========
[date] Refactor TimezoneCache to be separate from the OS

This refactoring is preparatory work to enable ICU to be the backend
for timezone information rather than system calls.

BUG=
==========

to

==========
[date] Refactor TimezoneCache to be separate from the OS

This refactoring is preparatory work to enable ICU to be the backend
for timezone information rather than system calls.

BUG=v8:6031
==========

[Dan Ehrenberg, 2017-03-02 12:19:52]

The CQ bit was checked by littledan@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-03-02 12:19:55]

Dry run: 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, 2017-03-02 12:21:42]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-03-02 12:21:43]

Dry run: Try jobs failed on following builders:
  v8_linux64_asan_rel_ng on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux64_asan_rel_ng/buil...)
  v8_linux64_verify_csa_rel_ng on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux64_verify_csa_rel_n...)
  v8_linux_arm_rel_ng on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_arm_rel_ng/builds/...)
  v8_mac_rel_ng on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_mac_rel_ng/builds/18339)

[Dan Ehrenberg, 2017-03-02 12:24:22]

Description was changed from

==========
[date] Refactor TimezoneCache to be separate from the OS

This refactoring is preparatory work to enable ICU to be the backend
for timezone information rather than system calls.

BUG=v8:6031
==========

to

==========
[date] Refactor TimezoneCache to be separate from the OS

This refactoring is preparatory work to enable ICU to be the backend
for timezone information rather than system calls. In the process, a
bit of code duplication that was inserted in the Solaris port patch is
eliminated here among modern POSIX backends.

One possible performance downside of this patch is that it introduces
a virtual method call for operations which were previously not virtual
methods. However, a couple factors mitigate this effect:
- The DateCache minimizes the need for calls into the TimezoneCache
- These calls were already not very high performance, as they included
  a system call which requires an RPC to get out of the sandbox, and
  they are surrounded by C++ builtins, which require a JS to C++
  transition.
- A future transition to ICU, enabled by this refactoring, may improve
  performance by eliminating the system call.
  the system call.

BUG=v8:6031
==========

[Dan Ehrenberg, 2017-03-02 12:32:13]

The CQ bit was checked by littledan@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-03-02 12:32:17]

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

[Dan Ehrenberg, 2017-03-02 12:34:10]

The CQ bit was checked by littledan@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-03-02 12:34:18]

Dry run: 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, 2017-03-02 12:36:46]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-03-02 12:36:48]

Dry run: Try jobs failed on following builders:
  v8_win64_rel_ng on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_win64_rel_ng/builds/23458)
  v8_win_compile_dbg on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_win_compile_dbg/builds/3...)
  v8_win_nosnap_shared_rel_ng on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_win_nosnap_shared_rel_ng...)
  v8_win_rel_ng on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_win_rel_ng/builds/23546)

[Dan Ehrenberg, 2017-03-02 12:46:55]

The CQ bit was checked by littledan@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-03-02 12:46:57]

Dry run: 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, 2017-03-02 12:49:27]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-03-02 12:49:27]

Dry run: Try jobs failed on following builders:
  v8_win64_rel_ng on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_win64_rel_ng/builds/23460)
  v8_win_compile_dbg on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_win_compile_dbg/builds/3...)
  v8_win_nosnap_shared_rel_ng on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_win_nosnap_shared_rel_ng...)
  v8_win_rel_ng on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_win_rel_ng/builds/23548)

[Dan Ehrenberg, 2017-03-02 12:53:25]

Description was changed from

==========
[date] Refactor TimezoneCache to be separate from the OS

This refactoring is preparatory work to enable ICU to be the backend
for timezone information rather than system calls. In the process, a
bit of code duplication that was inserted in the Solaris port patch is
eliminated here among modern POSIX backends.

One possible performance downside of this patch is that it introduces
a virtual method call for operations which were previously not virtual
methods. However, a couple factors mitigate this effect:
- The DateCache minimizes the need for calls into the TimezoneCache
- These calls were already not very high performance, as they included
  a system call which requires an RPC to get out of the sandbox, and
  they are surrounded by C++ builtins, which require a JS to C++
  transition.
- A future transition to ICU, enabled by this refactoring, may improve
  performance by eliminating the system call.
  the system call.

BUG=v8:6031
==========

to

==========
[date] Refactor TimezoneCache to be separate from the OS

This refactoring is preparatory work to enable ICU to be the backend
for timezone information rather than system calls. In the process, a
bit of code duplication that was inserted in the Solaris port patch is
eliminated here among modern POSIX backends.

One possible performance downside of this patch is that it introduces
a virtual method call for operations which were previously not virtual
methods. However, a couple factors mitigate this effect:
- The DateCache minimizes the need for calls into the TimezoneCache
- These calls were already not very high performance, as they included
  a system call which requires an RPC to get out of the sandbox, and
  they are surrounded by C++ builtins, which require a JS to C++
  transition.
- A future transition to ICU, enabled by this refactoring, may improve
  performance by eliminating the system call.

BUG=v8:6031
==========

[Dan Ehrenberg, 2017-03-02 12:55:21]

The CQ bit was checked by littledan@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-03-02 12:55:30]

Dry run: 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, 2017-03-02 13:23:55]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-03-02 13:23:57]

Dry run: This issue passed the CQ dry run.

[Dan Ehrenberg, 2017-03-02 14:10:12]

littledan@chromium.org changed reviewers:
+ jshin@chromium.org, ulan@chromium.org

[ulan, 2017-03-03 13:05:22]

lgtm

[Dan Ehrenberg, 2017-03-03 13:23:57]

The CQ bit was checked by littledan@chromium.org

[commit-bot: I haz the power, 2017-03-03 13:24:05]

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, 2017-03-03 13:54:59]

CQ is committing da patch.

Bot data: {"patchset_id": 120001, "attempt_start_ts": 1488547437786840,
"parent_rev": "e61ff99104c101a8555c3b9c9232712accaa4ce6", "commit_rev":
"ccfe50b95ae78c9b59d57ba47a734d63a3acb4f6"}

[commit-bot: I haz the power, 2017-03-03 13:55:03]

Description was changed from

==========
[date] Refactor TimezoneCache to be separate from the OS

This refactoring is preparatory work to enable ICU to be the backend
for timezone information rather than system calls. In the process, a
bit of code duplication that was inserted in the Solaris port patch is
eliminated here among modern POSIX backends.

One possible performance downside of this patch is that it introduces
a virtual method call for operations which were previously not virtual
methods. However, a couple factors mitigate this effect:
- The DateCache minimizes the need for calls into the TimezoneCache
- These calls were already not very high performance, as they included
  a system call which requires an RPC to get out of the sandbox, and
  they are surrounded by C++ builtins, which require a JS to C++
  transition.
- A future transition to ICU, enabled by this refactoring, may improve
  performance by eliminating the system call.

BUG=v8:6031
==========

to

==========
[date] Refactor TimezoneCache to be separate from the OS

This refactoring is preparatory work to enable ICU to be the backend
for timezone information rather than system calls. In the process, a
bit of code duplication that was inserted in the Solaris port patch is
eliminated here among modern POSIX backends.

One possible performance downside of this patch is that it introduces
a virtual method call for operations which were previously not virtual
methods. However, a couple factors mitigate this effect:
- The DateCache minimizes the need for calls into the TimezoneCache
- These calls were already not very high performance, as they included
  a system call which requires an RPC to get out of the sandbox, and
  they are surrounded by C++ builtins, which require a JS to C++
  transition.
- A future transition to ICU, enabled by this refactoring, may improve
  performance by eliminating the system call.

BUG=v8:6031

Review-Url: https://codereview.chromium.org/2731463003
Cr-Commit-Position: refs/heads/master@{#43588}
Committed:
https://chromium.googlesource.com/v8/v8/+/ccfe50b95ae78c9b59d57ba47a734d63a3a...
==========

[commit-bot: I haz the power, 2017-03-03 13:55:04]

Committed patchset #7 (id:120001) as
https://chromium.googlesource.com/v8/v8/+/ccfe50b95ae78c9b59d57ba47a734d63a3a...