| commit | 25799516481ff9e5f92bed487c10754b55b69e5b | [log] [tgz] |
|---|---|---|
| author | Tobias Tebbi <tebbi@chromium.org> | Thu Feb 15 13:27:12 2018 |
| committer | Commit Bot <commit-bot@chromium.org> | Mon Feb 19 15:25:23 2018 |
| tree | 09c326ad1e59d43062fb824d1f85fe356e6712c3 | |
| parent | e56eac022f3b046bdc0d7454bd920dae16737845 [diff] |
[turbofan] Masking/poisoning in codegen (optimized code, arm)
This introduces masking of loads with speculation bit during code generation.
At the moment, this is done only under the
--branch-load-poisoning flag, and this CL enlarges the set of supported
platforms from {x64} to {x64, arm}.
Overview of changes:
- new register configuration configuration with one register reserved for
the speculation poison/mask (kSpeculationPoisonRegister).
- in codegen, we introduce an update to the poison register at the starts
of all successors of branches (and deopts) that are marked as safety
branches (deopts).
- in memory optimizer, we lower all field and element loads to PoisonedLoads.
- poisoned loads are then masked in codegen with the poison register.
* only integer loads are masked at the moment.
Bug: chromium:798964
Change-Id: I37f5531fd18a96038ea8b059641e3dfc852c2d34
Reviewed-on: https://chromium-review.googlesource.com/913354
Commit-Queue: Michael Stanton <mvstanton@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51374}V8 is Google's open source JavaScript engine.
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