This CL implements an assembly order optimization that moves blocks
that end a loop with an unconditional backedge to the beginning of
the loop, saving a branch.
R=jarin@chromium.org,mstarzinger@chromium.org
BUG=v8:8423
Change-Id: I8a5d25f5472d71227af0f623277ea8d0a8d69867
Reviewed-on: https://chromium-review.googlesource.com/c/1335944
Commit-Queue: Ben Titzer <titzer@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57572}
This CL splits the backend of TurboFan off into its own directory,
without changing namespaces. This makes ownership management a bit
more fine-grained with a logical separation.
R=mstarzinger@chromium.org,jarin@chromium.org,adamk@chromium.org
Change-Id: I2ac40d6ca2c4f04b8474b630aae0286ecf79ef42
Reviewed-on: https://chromium-review.googlesource.com/c/1308333
Commit-Queue: Ben Titzer <titzer@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57437}
The idea is to mark all the branches and loads participating in array
bounds checks, and let them contribute-to/use the poisoning register.
In the code, the marks for array indexing operations now contain
"Critical" in their name. By default (--untrusted-code-mitigations),
we only instrument the "critical" operations with poisoning.
With that in place, we also remove the array masking approach based
on arithmetic.
Since we do not propagate the poison through function calls,
we introduce a node for poisoning an index that is passed through
function call - the typical example is the bounds-checked index
that is passed to the CharCodeAt builtin.
Most of the code in this CL is threads through the three levels of
protection (safe, critical, unsafe) for loads, branches and flags.
Bug: chromium:798964
Change-Id: Ief68e2329528277b3ba9156115b2a6dcc540d52b
Reviewed-on: https://chromium-review.googlesource.com/995413
Commit-Queue: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52883}
This CL changes the poisoning in the interpreter to use the
infrastructure used in the JIT.
This does not change the original flag semantics:
--branch-load-poisoning enables JIT mitigations as before.
--untrusted-code-mitigation enables the interpreter mitigations
(now realized using the compiler back-end), but does not enable
the back-end based mitigations for the Javascript JIT. So in effect
--untrusted-code-mitigation makes the CSA pipeline for bytecode handlers
use the same mechanics (including changed register allocation) that
--branch-load-poisoning enables for the JIT.
Bug: chromium:798964
Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel
Change-Id: If7f6852ae44e32e6e0ad508e9237f24dec7e5b27
Reviewed-on: https://chromium-review.googlesource.com/928881
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52243}
Remove IsBlockTerminator and introduce InstructionScheduler::AddTerminator in
order to handle block terminator instructions.
Instead of the kBlockTerminator flags, we now rely on Instruction::IsTrap(),
Instruction::IsDeoptimizeCall() and explicitly denoting block terminators
when adding them with InstructionScheduler::AddTerminator().
IsBlockTerminator incorrectly included deopts when they were not at the end of
a block, which meant that an instruction with side effects could have been
reordered with respect to a deopt as the deopt was not identified correctly.
Since the snapshot does not contain deopts, this is not causing any problems
at the moment (the scheduler is only enabled on the snapshot).
Change-Id: I1c2dad748a9398a3355630d9a542f4ac89afaa42
Reviewed-on: https://chromium-review.googlesource.com/960501
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Georgia Kouveli <georgia.kouveli@arm.com>
Cr-Commit-Position: refs/heads/master@{#52019}
