In order to reduce the codegen size of dynamic map checks, add the
ability to have an eager with resume deopt point, which can call
a given builitin to perform a more detailed check than can be done
in codegen, and then either deoptimizes itself (as if the calling
code had performed an eager deopt) or resumes execution in the
calling code after the check.
In addition, support for adding extra arguments to a
deoptimization continuation is added to enable us to pass the
necessary arguments to the DynamicMapChecks builtin.
Finally, a trampoline is added to the DynamicMapChecks which saves
the registers that might be clobbered by that builtin, to avoid
having to save them in the generated code. This trampoline also
performs the deoptimization based on the result of the
DynamicMapChecks builtin.
In order to ensure both the trampoline and DynamicMapChecks
builtin have the same call interface, and to limit the number
of registers that need saving in the trampoline, the
DynamicMapChecks builtin is moved to be a CSA builtin with a
custom CallInterfaceDescriptor, that calls an exported Torque
macro that implements the actual functionality.
All told, this changes the codegen for a monomorphic dynamic
map check from:
movl rbx,<expected_map>
cmpl [<object>-0x1],rbx
jnz <deferred_call>
resume_point:
...
deferred_call:
<spill registers>
movl rax,<slot>
movq rbx,<object>
movq rcx,<handler>
movq r10,<DynamicMapChecks>
call r10
cmpq rax,0x0
jz <restore_regs>
cmpq rax,0x1
jz <deopt_point_1>
cmpq rax,0x2
jz <deopt_point_2>
int3l
restore_regs:
<restore_regs>
jmp <resume_point>
...
deopt_point_1:
call Deoptimization_Eager
deopt_point_2:
call Deoptimization_Bailout
To: movl rax,<slot>
movl rcx,<expected_map>
movq rdx,<handler>
cmpl [<object>-0x1],rcx
jnz <deopt_point>
resume_point:
...
deopt_point:
call DynamicMapChecksTrampoline
jmp <resume_point>
BUG=v8:10582
Change-Id: Ica4927b9acc963b9b73dc62d9379a7815335650f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2560197
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71545}
... to --turbo-dynamic-map-checks. With the upcoming use in NCI code,
this feature is no longer used exclusively by Turboprop.
Bug: v8:8888
Change-Id: I61e01db086fd2e8566d2e2a09574be74b6e5a7bd
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2546693
Commit-Queue: Mythri Alle <mythria@chromium.org>
Reviewed-by: Mythri Alle <mythria@chromium.org>
Auto-Submit: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71263}
The dynamic map check builtin loads the feedback vector from the
function's frame, therefore it doesn't work if we inline the
function. We don't do inlining on TurboProp so this is fine, but
it was possible to enable dynamic map checks on TurboFan which does.
This change prevents that, and also makes the dynamic map checks flag
specific to TurboProp and no longer an implication, which also allos
it to be switched on the command line independenly of --turboprop.
BUG=chromium:1141502,v8:9684
Change-Id: I365de461a6373335a45a7a154af7d4cf1c13dc2c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2494928
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Reviewed-by: Mythri Alle <mythria@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70737}
The TryMigrateInstance should be passed the instance object to migrate,
not the map of the object. Also make the runtime function explicitly
check for JSObjects.
BUG=v8:9684
Change-Id: I03605d9f3103b618243c12ad0b63035484ef4134
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2487270
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70731}
