[interpreter] Switch context during stack unwinding.

[interpreter] Switch context during stack unwinding.

This implements proper context switching while unwinding the stack due
to an exception being handled in interpreted code. The context under
which the handler is scoped is being preserved in a dedicated register
while the try-block is running. Both, the stack unwinding machinery as
well as the graph builder, restore the context from that register.

R=rmcilroy@chromium.org,bmeurer@chromium.org
BUG=v8:4674
LOG=n

Committed: https://crrev.com/76bfc16bead1e41c977eb39790ab24400341d555
Cr-Commit-Position: refs/heads/master@{#33733}

[Michael Starzinger, 2016-02-03 14:34:01]

https://codereview.chromium.org/1665833002/diff/1/src/compiler/bytecode-graph...
File src/compiler/bytecode-graph-builder.cc (right):

https://codereview.chromium.org/1665833002/diff/1/src/compiler/bytecode-graph...
src/compiler/bytecode-graph-builder.cc:1669: int next_depth =
table->GetRangeDepth(current_exception_handler_);
disclosure: I understand that the naming of the HandlerTable::depth field is
off, because the interpreter is now "hijacking" it to hold the context register
index. However, I would like to do any potential renaming of that field in a
separate CL and not as part of this CL.

[Michael Starzinger, 2016-02-03 15:26:29]

Description was changed from

==========
[interpreter] Switch context during stack unwinding.

This implements proper context switching while unwinding the stack due
to and exception being handled in interpreted code. The context under
which the handler is scoped is being preserved in a dedicated register
while the try-block is running. Both, the stack unwinding machinery as
well as the graph builder, restore the context from that register.

R=rmcilroy@chromium.org,bmeurer@chromium.org
BUG=v8:4674
LOG=n
==========

to

==========
[interpreter] Switch context during stack unwinding.

This implements proper context switching while unwinding the stack due
to an exception being handled in interpreted code. The context under
which the handler is scoped is being preserved in a dedicated register
while the try-block is running. Both, the stack unwinding machinery as
well as the graph builder, restore the context from that register.

R=rmcilroy@chromium.org,bmeurer@chromium.org
BUG=v8:4674
LOG=n
==========

[rmcilroy, 2016-02-04 12:22:49]

Nice, LGTM.

https://codereview.chromium.org/1665833002/diff/60001/src/compiler/bytecode-g...
File src/compiler/bytecode-graph-builder.cc (right):

https://codereview.chromium.org/1665833002/diff/60001/src/compiler/bytecode-g...
src/compiler/bytecode-graph-builder.cc:1675: int next_depth =
table->GetRangeDepth(current_exception_handler_);
nit - could we call the local context_register instead (with a comment that we
are hijacking the depth field for this).

[Michael Starzinger, 2016-02-04 12:40:32]

Thanks. Addressed comments. Will rebase and land now.

https://codereview.chromium.org/1665833002/diff/60001/src/compiler/bytecode-g...
File src/compiler/bytecode-graph-builder.cc (right):

https://codereview.chromium.org/1665833002/diff/60001/src/compiler/bytecode-g...
src/compiler/bytecode-graph-builder.cc:1675: int next_depth =
table->GetRangeDepth(current_exception_handler_);
On 2016/02/04 12:22:49, rmcilroy wrote:
> nit - could we call the local context_register instead (with a comment that we
> are hijacking the depth field for this).

Done.

[Michael Starzinger, 2016-02-04 13:42:10]

The CQ bit was checked by mstarzinger@chromium.org

[Michael Starzinger, 2016-02-04 13:42:11]

The patchset sent to the CQ was uploaded after l-g-t-m from
rmcilroy@chromium.org
Link to the patchset: https://codereview.chromium.org/1665833002/#ps100001
(title: "Rebased.")

[commit-bot: I haz the power, 2016-02-04 13:42:17]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1665833002/100001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1665833002/100001

[commit-bot: I haz the power, 2016-02-04 13:43:49]

Description was changed from

==========
[interpreter] Switch context during stack unwinding.

This implements proper context switching while unwinding the stack due
to an exception being handled in interpreted code. The context under
which the handler is scoped is being preserved in a dedicated register
while the try-block is running. Both, the stack unwinding machinery as
well as the graph builder, restore the context from that register.

R=rmcilroy@chromium.org,bmeurer@chromium.org
BUG=v8:4674
LOG=n
==========

to

==========
[interpreter] Switch context during stack unwinding.

This implements proper context switching while unwinding the stack due
to an exception being handled in interpreted code. The context under
which the handler is scoped is being preserved in a dedicated register
while the try-block is running. Both, the stack unwinding machinery as
well as the graph builder, restore the context from that register.

R=rmcilroy@chromium.org,bmeurer@chromium.org
BUG=v8:4674
LOG=n
==========

[commit-bot: I haz the power, 2016-02-04 13:43:50]

Committed patchset #6 (id:100001)

[commit-bot: I haz the power, 2016-02-04 13:44:02]

Description was changed from

==========
[interpreter] Switch context during stack unwinding.

This implements proper context switching while unwinding the stack due
to an exception being handled in interpreted code. The context under
which the handler is scoped is being preserved in a dedicated register
while the try-block is running. Both, the stack unwinding machinery as
well as the graph builder, restore the context from that register.

R=rmcilroy@chromium.org,bmeurer@chromium.org
BUG=v8:4674
LOG=n
==========

to

==========
[interpreter] Switch context during stack unwinding.

This implements proper context switching while unwinding the stack due
to an exception being handled in interpreted code. The context under
which the handler is scoped is being preserved in a dedicated register
while the try-block is running. Both, the stack unwinding machinery as
well as the graph builder, restore the context from that register.

R=rmcilroy@chromium.org,bmeurer@chromium.org
BUG=v8:4674
LOG=n

Committed: https://crrev.com/76bfc16bead1e41c977eb39790ab24400341d555
Cr-Commit-Position: refs/heads/master@{#33733}
==========

[commit-bot: I haz the power, 2016-02-04 13:44:03]

Patchset 6 (id:??) landed as
https://crrev.com/76bfc16bead1e41c977eb39790ab24400341d555
Cr-Commit-Position: refs/heads/master@{#33733}