This reverts commit 087e95ba63.
Reason for revert: <INSERT REASONING HERE>
Original change's description:
> [Compiler] Use IdentityMap to store jobs in CompilerDispatcher.
>
> Stores jobs in an IdentityMap keyed by their SharedFunctionInfo to enable
> fast checking of whether a job is enqueued.
>
> BUG=v8:5203
>
> Change-Id: I6c37972093515a27077f79594cad27e32e1a4e7c
> Reviewed-on: https://chromium-review.googlesource.com/444768
> Reviewed-by: Jochen Eisinger <jochen@chromium.org>
> Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
> Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#43370}
TBR=rmcilroy@chromium.org,jochen@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5203
Change-Id: I5d1101bdae6939378dad595b26698fe2aaaad35e
Reviewed-on: https://chromium-review.googlesource.com/446357
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#43372}
Stores jobs in an IdentityMap keyed by their SharedFunctionInfo to enable
fast checking of whether a job is enqueued.
BUG=v8:5203
Change-Id: I6c37972093515a27077f79594cad27e32e1a4e7c
Reviewed-on: https://chromium-review.googlesource.com/444768
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#43370}
v8 allows the embedder to specify a global template to use when
creating a new context. However, v8 does not use the supplied
template directly when creating the global proxy: it creates a
unique template for each global proxy. However, this is problematic
for remote contexts: functions cannot use strict receiver checks
with the remote context, as the global template will never match
the global proxy.
To fix this, remote contexts now also include a remote global
object in the prototype chain that is instantiated with the global
template. This mirrors the way the global proxy is configured for a
full v8 context, and allows strict receiver checks to work.
BUG=527190
Review-Url: https://codereview.chromium.org/2677653002
Cr-Commit-Position: refs/heads/master@{#43361}
Reason for revert:
Due to arm64 failures
Original issue's description:
> [interpreter] Create custom call opcodes for specific argument counts
>
> Specifically, add bytecodes for Call0, Call1, Call2, CallProperty0, CallProperty1,
> and CallProperty2. Also share the bytecode handler code between between
> equivalent CallX and CallPropertyX handlers.
>
> Review-Url: https://codereview.chromium.org/2684993002
> Cr-Commit-Position: refs/heads/master@{#43290}
> Committed: 00d6f1f80aTBR=rmcilroy@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
Review-Url: https://codereview.chromium.org/2709533002
Cr-Commit-Position: refs/heads/master@{#43308}
Specifically, add bytecodes for Call0, Call1, Call2, CallProperty0, CallProperty1,
and CallProperty2. Also share the bytecode handler code between between
equivalent CallX and CallPropertyX handlers.
Review-Url: https://codereview.chromium.org/2684993002
Cr-Commit-Position: refs/heads/master@{#43290}
... which is used for initializing properties with non compile time values.
Currently we use StoreOwnIC only for storing properties that already exist
in the boilerplate therefore we can reuse StoreIC dispatcher.
The proper StoreOwnIC dispatcher will be implemented in a separate CL.
BUG=v8:5495, v8:4414
Change-Id: I9c33fdb8499ec5be2c7fce1ecb6ce7aa285e5844
Reviewed-on: https://chromium-review.googlesource.com/443588
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#43285}
Add `ValueSerializer::SetTreatArrayBufferViewsAsHostObjects()` which
instructs the `ValueSerializer` to treat ArrayBufferView objects as
host objects.
BUG=v8:5926
Review-Url: https://codereview.chromium.org/2696133007
Cr-Commit-Position: refs/heads/master@{#43281}
https://crrev.com/2500363002 updated FunctionTemplate::HasInstance to
follow the hidden prototype chain of a global proxy to the global
object. However, remote contexts don't have a global object to check;
instead, teach the instance check knows about the conventions of
global proxy setup and have it also check the constructor's prototype.
Similarly, also teach Object::FindInstanceInPrototypeChain about the
unusual conventions for remote contexts.
BUG=527190
Review-Url: https://codereview.chromium.org/2698683003
Cr-Commit-Position: refs/heads/master@{#43263}
Before this patch, the registers needed for bytecode dispatch in interpreter
handlers were inconsistently stored in the interpreter frame and/or kept in
values that remained live across calls.
After this patch, these registers are explicitly reloaded after calls, making it
possible to elide the spills of those registers before the call in many cases.
Some highlights from the CL:
* Added methods to the CSA and InterpreterAssembler to efficiently store and
load Smis values and Smi interpreter registers on x64 without explicit
tagging/untagging.
* Created Variables for all of the interpreter-internal values that need to be
reloaded before bytecode dispatch at the end of an interpreter handler.
* The bytecode offset can be written out early in a handler by marking it
has having a call along it's critical path. By moving this early in a
handler, it becomes possible to use memory operands for pushes used to
marshall parameters when making calls.
Change-Id: Icf8d7798789f88a4489e06a7092616bbbb881577
Reviewed-on: https://chromium-review.googlesource.com/442566
Commit-Queue: Daniel Clifford <danno@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#43260}
The serializer won't ever write a more complex object. Not validating this
allows other things to be used as keys, and converted to string when the
property set actually occurs. It turns out this gives an opportunity to trigger
OOM by giving an object a key which is a very large sparse array (whose string
representation is very large).
This case is now rejected by the deserializer.
BUG=chromium:686511
Review-Url: https://codereview.chromium.org/2697023002
Cr-Commit-Position: refs/heads/master@{#43249}
This handles arithmetic addition operations during the early type-hint
lowering (i.e. during graph construction). The string addition case is
still handled by {JSTypedLowering} as it needs static type information.
R=bmeurer@chromium.org
Change-Id: I9df47dfc5bf7613c51f6d803ab43d5d3f6c21be8
Reviewed-on: https://chromium-review.googlesource.com/443185
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#43235}
This handles all arithmetic binary operations except addition during the
early type-hint lowering (i.e. during graph construction). We still use
static type information to potentially further reduce the speculative
operations down to pure operations during the typed lowering phase.
R=bmeurer@chromium.org
Change-Id: I8b93fd7c46ec8e5b81234a49624d503520c3d082
Reviewed-on: https://chromium-review.googlesource.com/443105
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#43218}
This allows part of typed lowering that is solely based on type-hints to
run as part of the graph construction. The lowering in question does not
inspect types and hence doesn't require the typer to have run before. We
insert the speculative simplied-level operations in favor of the generic
JavaScript-level variants.
R=bmeurer@chromium.org
Change-Id: I5f0549fc1e4ff607622ee9059e6232a32f77db2e
Reviewed-on: https://chromium-review.googlesource.com/442584
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#43208}
If a job was already enqueued, EnqueueAndStep would still step the job one
more step. However, since it didn't take the job out of the
pending_background_jobs pool, the job could get picked up by a background
thread which would try to step it, but it the job is now at a step which
can't be run on the background.
BUG=v8:5203,chromium:685515
Change-Id: I2cee2a33625ba455aca49a8037601be9ff8bb73f
Reviewed-on: https://chromium-review.googlesource.com/441084
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#43121}
Don't block on inner function compilation before competing outer function
compilation. Instead wait for the compilation to complete when the function
is called.
BUG=v8:5203
Review-Url: https://codereview.chromium.org/2686673002
Cr-Commit-Position: refs/heads/master@{#43116}
Removes handles from bytecode generation, instead storing
un-internalized AstValues (and other, similar values such as Scopes and
AstRawStrings) in the constant array builder.
This will allow us in the future to generate the bytecode before
internalizing the AST.
BUG=v8:5832
Change-Id: I3b8be8f7329a484eb1e5d12808b001d3475239da
Reviewed-on: https://chromium-review.googlesource.com/439326
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Marja Hölttä <marja@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#43115}
When running main-thread compiler-dispatcher jobs, ensure that we enter the
correct Context. Also adds a test for compiling an extension in the compiler
dispatcher to ensure that idle tasks enter the correct context before
finalizing the compilation.
BUG=v8:5203
Review-Url: https://codereview.chromium.org/2679193004
Cr-Commit-Position: refs/heads/master@{#43111}
This introduces new maps to track whether we have created at most one
closure. If we have created just one closure, Turbofan will
specialize the code to its context.
Review-Url: https://codereview.chromium.org/2680313002
Cr-Commit-Position: refs/heads/master@{#43108}
In order to compile eager inner functions on a background thread we need to
keep the handles created during parsing and scope analysis alive until the
background compilation is complete. In order to do that, we allocate the
handles in a deferred handle scope and keep the deferred handles alive with
a shared_ptr in the ParseInfo and CompileInfo respectively.
BUG=v8:5203
Review-Url: https://codereview.chromium.org/2650883002
Cr-Commit-Position: refs/heads/master@{#43107}
Reason for revert:
Issue on arm64:
https://build.chromium.org/p/client.v8.ports/builders/V8%20Linux%20-%20arm64%20-%20sim/builds/5752
Original issue's description:
> [Compiler] Enable handles created during parsing and scope analysis to be deferred.
>
> In order to compile eager inner functions on a background thread we need to
> keep the handles created during parsing and scope analysis alive until the
> background compilation is complete. In order to do that, we allocate the
> handles in a deferred handle scope and keep the deferred handles alive with
> a shared_ptr in the ParseInfo and CompileInfo respectively.
>
> BUG=v8:5203
>
> Review-Url: https://codereview.chromium.org/2650883002
> Cr-Commit-Position: refs/heads/master@{#43091}
> Committed: 9346cd9b4cTBR=marja@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5203
Review-Url: https://codereview.chromium.org/2687973003
Cr-Commit-Position: refs/heads/master@{#43093}
In order to compile eager inner functions on a background thread we need to
keep the handles created during parsing and scope analysis alive until the
background compilation is complete. In order to do that, we allocate the
handles in a deferred handle scope and keep the deferred handles alive with
a shared_ptr in the ParseInfo and CompileInfo respectively.
BUG=v8:5203
Review-Url: https://codereview.chromium.org/2650883002
Cr-Commit-Position: refs/heads/master@{#43091}
In order to allow parallel compilation of eager inner functions, we need to
seperate the zone used for parsing (which will be shared between all the
parallel compile jobs) and the zone used for compilation. This CL changes
CompilationInfo to require a zone (which can be different from the zone in
ParseInfo). We then seal the ParseInfo zone after parsing and analysis is done
to prevent any further allocation in that zone, so that it can be shared
(read-only) with the parallel compile jobs.
BUG=v8:5203
Review-Url: https://codereview.chromium.org/2645403002
Cr-Commit-Position: refs/heads/master@{#43089}
arguments.h is one of the headers including objects-inl.h. Files needing
objects-inl.h used to innocently pull in debug.h, so that needs to be fixed now
too.
BUG=v8:5294
R=mstarzinger@chromium.org
Change-Id: I8ce671c533ed757103ef9a3b0bf0a0509230fdd8
Reviewed-on: https://chromium-review.googlesource.com/439287
Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#43054}
Since the empty string is canonical HeapObject now, we can use
this fact to optimize
- strict equality comparisons with the empty string to a
simple ReferenceEqual operation, and
- optimize ToBoolean to avoid instance type checks completely.
Drive-by-fix: Allow InternalizedString for Type::HeapConstant
in the type system. This is safe, since InternalizedStrings
can be compared to other heap constants by reference (except
for non-InternalizedStrings, which are excluded from the
HeapConstant type).
BUG=v8:5267
R=yangguo@chromium.org
Review-Url: https://codereview.chromium.org/2681273002
Cr-Commit-Position: refs/heads/master@{#43050}
Without doing this, a JSMessageObject can be kept alive by the isolate, which
in turn keeps the context alive, until the message is cleared.
BUG=v8:5941
Review-Url: https://codereview.chromium.org/2675203005
Cr-Commit-Position: refs/heads/master@{#43043}
Arm64 compiles "x +_64 (y >> shift)" into a single instruction if
"shift" is a constant. The code generator expects that "shift" is a
32 bit constant. however, TurboFan can also pass in a 64 bit constant,
which caused a crash in the code generator.
With this CL we cast the constant of TurboFan to an int in the
instruction selector and thereby satisfy the assumption of the code
generator. This should be correct since the code generator anyways cast
the "shift" to an int5 or int6 eventually.
R=v8-arm-ports@googlegroups.com
BUG=v8:5923
Review-Url: https://codereview.chromium.org/2669203005
Cr-Commit-Position: refs/heads/master@{#43036}
Reason for revert:
False alarm, bot hiccup
Original issue's description:
> Revert of Reland: [Parse] ParseInfo owns the parsing Zone. (patchset #7 id:140001 of https://codereview.chromium.org/2632123006/ )
>
> Reason for revert:
> Speculative revert because of revert needed for https://codereview.chromium.org/2632123006
>
> Original issue's description:
> > Reland: [Parse] ParseInfo owns the parsing Zone.
> >
> > Moves ownership of the parsing Zone to ParseInfo with a shared_ptr. This is
> > in preperation for enabling background compilation jobs for inner functions
> > share the AST in the outer-function's parse zone memory (read-only), with the
> > and zone being released when all compilation jobs have completed.
> >
> > BUG=v8:5203,v8:5215
> >
> > Review-Url: https://codereview.chromium.org/2632123006
> > Cr-Original-Commit-Position: refs/heads/master@{#42993}
> > Committed: 14fb337200
> > Review-Url: https://codereview.chromium.org/2632123006
> > Cr-Commit-Position: refs/heads/master@{#42996}
> > Committed: 9e7d5a6065
>
> TBR=marja@chromium.org,mstarzinger@chromium.org,ahaas@chromium.org,verwaest@chromium.org,rmcilroy@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=v8:5203,v8:5215
>
> Review-Url: https://codereview.chromium.org/2683733002
> Cr-Commit-Position: refs/heads/master@{#43008}
> Committed: 9fe08ec067TBR=marja@chromium.org,mstarzinger@chromium.org,ahaas@chromium.org,verwaest@chromium.org,rmcilroy@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5203,v8:5215
Review-Url: https://codereview.chromium.org/2679303003
Cr-Commit-Position: refs/heads/master@{#43015}
Reason for revert:
False alarm, bot hiccup
Original issue's description:
> Revert of Thread maybe-assigned through the bytecodes. (patchset #5 id:80001 of https://codereview.chromium.org/2655733003/ )
>
> Reason for revert:
> needed for properly reverting f3ae5ccf57
>
> Original issue's description:
> > Thread maybe-assigned through the bytecodes.
> >
> > This introduces LoadImmutableContextSlot and LoadImmutableCurrentContextSlot
> > bytecodes, which are emitted when reading from never-assigned context slot.
> >
> > There is a subtlety here: the slot are not immutable, the meaning is
> > actually undefined-or-hole-or-immutable.
> >
> > Review-Url: https://codereview.chromium.org/2655733003
> > Cr-Commit-Position: refs/heads/master@{#43000}
> > Committed: 17c2dd3886
>
> TBR=rmcilroy@chromium.org,bmeurer@chromium.org,neis@chromium.org,jarin@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
>
> Review-Url: https://codereview.chromium.org/2680923003
> Cr-Commit-Position: refs/heads/master@{#43011}
> Committed: ece4e54a31TBR=rmcilroy@chromium.org,bmeurer@chromium.org,neis@chromium.org,jarin@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
Review-Url: https://codereview.chromium.org/2679953003
Cr-Commit-Position: refs/heads/master@{#43012}
Reason for revert:
needed for properly reverting f3ae5ccf57
Original issue's description:
> Thread maybe-assigned through the bytecodes.
>
> This introduces LoadImmutableContextSlot and LoadImmutableCurrentContextSlot
> bytecodes, which are emitted when reading from never-assigned context slot.
>
> There is a subtlety here: the slot are not immutable, the meaning is
> actually undefined-or-hole-or-immutable.
>
> Review-Url: https://codereview.chromium.org/2655733003
> Cr-Commit-Position: refs/heads/master@{#43000}
> Committed: 17c2dd3886TBR=rmcilroy@chromium.org,bmeurer@chromium.org,neis@chromium.org,jarin@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
Review-Url: https://codereview.chromium.org/2680923003
Cr-Commit-Position: refs/heads/master@{#43011}
Reason for revert:
Speculative revert because of revert needed for https://codereview.chromium.org/2632123006
Original issue's description:
> Reland: [Parse] ParseInfo owns the parsing Zone.
>
> Moves ownership of the parsing Zone to ParseInfo with a shared_ptr. This is
> in preperation for enabling background compilation jobs for inner functions
> share the AST in the outer-function's parse zone memory (read-only), with the
> and zone being released when all compilation jobs have completed.
>
> BUG=v8:5203,v8:5215
>
> Review-Url: https://codereview.chromium.org/2632123006
> Cr-Original-Commit-Position: refs/heads/master@{#42993}
> Committed: 14fb337200
> Review-Url: https://codereview.chromium.org/2632123006
> Cr-Commit-Position: refs/heads/master@{#42996}
> Committed: 9e7d5a6065TBR=marja@chromium.org,mstarzinger@chromium.org,ahaas@chromium.org,verwaest@chromium.org,rmcilroy@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5203,v8:5215
Review-Url: https://codereview.chromium.org/2683733002
Cr-Commit-Position: refs/heads/master@{#43008}
This introduces LoadImmutableContextSlot and LoadImmutableCurrentContextSlot
bytecodes, which are emitted when reading from never-assigned context slot.
There is a subtlety here: the slot are not immutable, the meaning is
actually undefined-or-hole-or-immutable.
Review-Url: https://codereview.chromium.org/2655733003
Cr-Commit-Position: refs/heads/master@{#43000}
... and TypeFeedbackMetadata to FeedbackMetadata.
BUG=
Change-Id: I2556d1c2a8f37b8cf3d532cc98d973b6dc7e9e6c
Reviewed-on: https://chromium-review.googlesource.com/439244
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#42999}
Moves ownership of the parsing Zone to ParseInfo with a shared_ptr. This is
in preperation for enabling background compilation jobs for inner functions
share the AST in the outer-function's parse zone memory (read-only), with the
and zone being released when all compilation jobs have completed.
BUG=v8:5203,v8:5215
Review-Url: https://codereview.chromium.org/2632123006
Cr-Original-Commit-Position: refs/heads/master@{#42993}
Committed: 14fb337200
Review-Url: https://codereview.chromium.org/2632123006
Cr-Commit-Position: refs/heads/master@{#42996}
Reason for revert:
doesn't compile on ToT
Original issue's description:
> Reland: [Parse] ParseInfo owns the parsing Zone.
>
> Moves ownership of the parsing Zone to ParseInfo with a shared_ptr. This is
> in preperation for enabling background compilation jobs for inner functions
> share the AST in the outer-function's parse zone memory (read-only), with the
> and zone being released when all compilation jobs have completed.
>
> BUG=v8:5203,v8:5215
>
> Review-Url: https://codereview.chromium.org/2632123006
> Cr-Commit-Position: refs/heads/master@{#42993}
> Committed: 14fb337200TBR=marja@chromium.org,mstarzinger@chromium.org,ahaas@chromium.org,verwaest@chromium.org,rmcilroy@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5203,v8:5215
Review-Url: https://codereview.chromium.org/2685543003
Cr-Commit-Position: refs/heads/master@{#42994}
Moves ownership of the parsing Zone to ParseInfo with a shared_ptr. This is
in preperation for enabling background compilation jobs for inner functions
share the AST in the outer-function's parse zone memory (read-only), with the
and zone being released when all compilation jobs have completed.
BUG=v8:5203,v8:5215
Review-Url: https://codereview.chromium.org/2632123006
Cr-Commit-Position: refs/heads/master@{#42993}
This correctly marks the {JSCreate} operator as potentially throwing,
since it might trigger a property access of the 'prototype' property
during instantiation. This is observable, can throw (not kNoThrow),
might have side-effects (not kNoWrite), or even trigger a lazy deopt
event (not kNoDeopt). The inlining logic has been adapted to wire up
control projections accordingly.
Note that this does not yet take care of the "after" frame-state which
is associated with the {JSCreate} node introduced by the inliner. We
still might re-evaluate the property access upon lazy deoptimization.
R=bmeurer@chromium.org
TEST=mjsunit/regress/regress-5638
BUG=v8:5638
Review-Url: https://codereview.chromium.org/2671203003
Cr-Commit-Position: refs/heads/master@{#42981}
TypeFeedbackVectors are strongly rooted by a closure. However, in modern
JavaScript closures are created and abandoned more freely. An important
closure may not be present in the root-set at time of garbage collection,
even though we've cached optimized code and use it regularly. For
example, consider leaf functions in an event dispatching system. They may
well be "hot," but tragically non-present when we collect the heap.
Until now, we've relied on a weak root to cache the feedback vector in
this case. Since there is no way to signal intent or relative importance,
this weak root is as susceptible to clearing as any other weak root at
garbage collection time.
Meanwhile, the feedback vector has become more important. All of our
ICs store their data there. Literal and regex boilerplates are stored there.
If we lose the vector, then we not only lose optimized code built from
it, we also lose the very feedback which allowed us to create that optimized
code. Therefore it's vital to express that dependency through the root
set.
This CL does this by creating a strong link to a feedback
vector at the instantiation site of the function closure.
This instantiation site is in the code and feedback vector
of the outer closure.
BUG=v8:5456
Review-Url: https://codereview.chromium.org/2674593003
Cr-Commit-Position: refs/heads/master@{#42953}
