Add script context with context-allocated "const this"

Add script context with context-allocated "const this"

R=rossberg@chromium.org
LOG=N
BUG=498811
Committed: https://crrev.com/fa32d461c16a053cc6d48d3fb326016bc2765765
Cr-Commit-Position: refs/heads/master@{#28988}

[wingo, 2015-06-11 15:38:00]

An early patch.  It works for "this", e.g.:

$ out/x64.debug/d8 --print_scopes -e this
global { // (0, 4)
  // scope has trivial outer context
  // 1 stack slots
  // temporary vars:
  TEMPORARY .result;  // local[0]
  // local vars:
  DYNAMIC_GLOBAL this;  // 
}

But eval('foo') doesn't work because ResolvePossiblyDirectSloppyEval() does a
scope->Lookup("this") at compile-time, and the "this" binding isn't lexically
visible in the scope tree, because declarative scopes from other script contexts
aren't statically resolveable.  But, it should be possible to also fix
ResolvePossiblyDirectBlabla in this CL too, because the badness from
https://codereview.chromium.org/1097283003/#msg41 shouldn't affect us any more.

[wingo, 2015-06-11 16:25:36]

Updated patch works!  Now to implement for the eleventy billion architectures.

[wingo, 2015-06-11 16:26:05]

wingo@igalia.com changed reviewers:
+ mstarzinger@chromium.org

[wingo, 2015-06-11 16:26:17]

On 2015/06/11 16:25:36, wingo wrote:
> Updated patch works!  Now to implement for the eleventy billion architectures.

+mstarzinger for the TF patch.

[wingo, 2015-06-11 16:45:31]

The CQ bit was checked by wingo@igalia.com to run a CQ dry run

[commit-bot: I haz the power, 2015-06-11 16:45:42]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1179893002/40001

[commit-bot: I haz the power, 2015-06-11 17:03:00]

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

[commit-bot: I haz the power, 2015-06-11 17:03:01]

Dry run: Try jobs failed on following builders:
  v8_linux64_avx2_rel on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux64_avx2_rel/builds/...)

[rossberg, 2015-06-11 17:05:07]

lgtm

[wingo, 2015-06-11 19:46:27]

The CQ bit was checked by wingo@igalia.com to run a CQ dry run

[wingo, 2015-06-11 19:46:27]

The patchset sent to the CQ was uploaded after l-g-t-m from
rossberg@chromium.org
Link to the patchset: https://codereview.chromium.org/1179893002/#ps60001
(title: "Fix TF unit test.  "delete this" true for any var named this, even if
not Variable::THIS")

[commit-bot: I haz the power, 2015-06-11 19:46:46]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1179893002/60001

[commit-bot: I haz the power, 2015-06-11 19:51:43]

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

[commit-bot: I haz the power, 2015-06-11 19:51:43]

Dry run: Try jobs failed on following builders:
  v8_linux_nodcheck_rel on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_nodcheck_rel/build...)

[wingo, 2015-06-11 19:58:36]

The CQ bit was checked by wingo@igalia.com to run a CQ dry run

[wingo, 2015-06-11 19:58:36]

The patchset sent to the CQ was uploaded after l-g-t-m from
rossberg@chromium.org
Link to the patchset: https://codereview.chromium.org/1179893002/#ps80001
(title: "Fix release-mode compilation warning/error")

[commit-bot: I haz the power, 2015-06-11 19:58:58]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1179893002/80001

[commit-bot: I haz the power, 2015-06-11 20:23:40]

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

[commit-bot: I haz the power, 2015-06-11 20:23:41]

Dry run: Try jobs failed on following builders:
  v8_linux_arm64_rel on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_arm64_rel/builds/6581)

[wingo, 2015-06-12 07:49:50]

The CQ bit was checked by wingo@igalia.com to run a CQ dry run

[wingo, 2015-06-12 07:49:50]

The patchset sent to the CQ was uploaded after l-g-t-m from
rossberg@chromium.org
Link to the patchset: https://codereview.chromium.org/1179893002/#ps100001
(title: "arm64 fixups")

[commit-bot: I haz the power, 2015-06-12 07:49:59]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1179893002/100001

[Michael Starzinger, 2015-06-12 08:06:10]

LGTM on the TurboFan part with a few nits.

https://codereview.chromium.org/1179893002/diff/100001/src/compiler/ast-graph...
File src/compiler/ast-graph-builder.cc (right):

https://codereview.chromium.org/1179893002/diff/100001/src/compiler/ast-graph...
src/compiler/ast-graph-builder.cc:2857: // "delete this" is allowed.  (It could
be that the "this" variable has
nit: Can we merge this comment with the one two lines above, because it
basically tries to express the same thing.

https://codereview.chromium.org/1179893002/diff/100001/src/compiler/ast-graph...
src/compiler/ast-graph-builder.cc:2862: *variable->name() ==
*isolate()->factory()->this_string());
nit: This heavily relies on the fact that variable->name() is internalized. Can
we move this into a Variable::IsThisName(Isolate*) helper so that it not spread
across the codebase?

https://codereview.chromium.org/1179893002/diff/100001/src/compiler/ast-graph...
src/compiler/ast-graph-builder.cc:3312: bool is_this = *variable->name() ==
*isolate()->factory()->this_string();
nit: See comment above.

[commit-bot: I haz the power, 2015-06-12 08:28:05]

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

[commit-bot: I haz the power, 2015-06-12 08:28:06]

Dry run: This issue passed the CQ dry run.

[wingo, 2015-06-12 08:54:23]

The CQ bit was checked by wingo@igalia.com

[wingo, 2015-06-12 08:54:24]

The patchset sent to the CQ was uploaded after l-g-t-m from
rossberg@chromium.org, mstarzinger@chromium.org
Link to the patchset: https://codereview.chromium.org/1179893002/#ps120001
(title: "Factor out Variable::HasThisName")

[commit-bot: I haz the power, 2015-06-12 08:54:33]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1179893002/120001

[commit-bot: I haz the power, 2015-06-12 09:35:56]

Committed patchset #7 (id:120001)

[commit-bot: I haz the power, 2015-06-12 09:36:03]

Patchset 7 (id:??) landed as
https://crrev.com/fa32d461c16a053cc6d48d3fb326016bc2765765
Cr-Commit-Position: refs/heads/master@{#28988}

[Michael Achenbach, 2015-06-12 10:07:00]

A revert of this CL (patchset #7 id:120001) has been created in
https://codereview.chromium.org/1180043004/ by machenbach@chromium.org.

The reason for reverting is: [Sheriff] Breaks gc mole:
http://build.chromium.org/p/client.v8/builders/V8%20Linux%20-%20gcmole/builds....

[Michael Achenbach, 2015-06-12 11:47:05]

There was also this error:
http://build.chromium.org/p/client.v8/builders/V8%20Linux%20-%20nosnap/builds...