This is a reland of commit 07e11a64e4.
The original change removed the fill_thehole_and_call_runtime bailout
in StringBuiltinsAssembler::StringToArray() so when the string
is external and cannot be unpacked, the FixedArray won't be filled
with holes before we call into the runtime, thus failing a
heap verification if a GC happens before the array is filled. This
reland adds back the bailout for this case.
Bug: v8:12718, chromium:1330410
Original change's description:
> [heap] pre-populate the single_character_string_cache
>
> This simplifies the code and removes the runtime overhead of
> spontaneously adding strings to the cache.
>
> Bug: v8:12718
> Change-Id: I2ed49bd82e3baf2563eeb8f463be72c0308c52c5
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3616553
> Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
> Reviewed-by: Leszek Swirski <leszeks@chromium.org>
> Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
> Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
> Commit-Queue: Joyee Cheung <joyee@igalia.com>
> Cr-Commit-Position: refs/heads/main@{#80803}
Change-Id: I25e8724d511a8d0d971fa2a9b6ba8a0eafce4413
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3793525
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Commit-Queue: Joyee Cheung <joyee@igalia.com>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82082}
If we grow memory (out-of-place, so only without trap handling and only
if the maximum is >1GB) and the previous size is close to the maximum,
then the minimum growth we calculate can be bigger than the allowed
maximum. In this situation, the {std::clamp} has undefined behaviour,
since the provided lower limit is bigger then the upper limit.
Thus apply {std::min} and {std::max} in an order such that {max_pages}
has precedence over {min_growth}.
R=thibaudm@chromium.org
Bug: chromium:1348335
Change-Id: I4f9e9ce10a0685892248eaf0e06ffd2e84b9a069
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3793396
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82081}
Due to popular demand.
As a necessary byproduct, this drops our former experimental in-progress
support for accessing struct fields from JS as `.field0` etc. If we need
something similar in the future, we'll have to build a new mechanism for
it that scales to >1020 fields.
Bug: v8:7748
Change-Id: I08b2051bd9f76cf7128f3d4c74910ca891c38130
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3793616
Reviewed-by: Manos Koukoutos <manoskouk@chromium.org>
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82079}
Call test functions immediately, and make them print their name before
execution.
R=thibaudm@chromium.org
Change-Id: I2057e2b3c2032c342a86705dbda8992aa54493e5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3793612
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82077}
Table<any> is not allowed any more and may therefore not be generated by
the fuzzer. Instead, the new type is table<externref>.
Bug: chromium:1348437
Change-Id: Ibf788222fc777508e59178db48e6497a18b250d8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3793610
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Auto-Submit: Matthias Liedtke <mliedtke@chromium.org>
Reviewed-by: Manos Koukoutos <manoskouk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82073}
This is required by the MVP spec. In the future, it might be possible
to pass values for any immutable fields.
Bug: v8:7748
Change-Id: Ie7705b48e9d6ebb87d5e1b0a2a10556302395db6
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3793383
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82072}
Currently, we canonicalize types for call_indirect by looking in the
current module for a signature of the same shape. This is not enough
as of wasm-gc. Instead, the canonical identifier representing a type
has to be computed via isorecursive canonicalization.
This change is implemented behind a flag for now.
Future work: Also integrate export wrappers with isorecursive
canonical types. We need to store wrappers in instance-independent
storage.
Drive-by:
- Always emit type check for call_indirect. We did not emit a check
only when typed-function-references was enabled, but not gc. This
is not something that will be possible long-term.
- Fix some wasm cctests.
Bug: v8:7748
Change-Id: I7cced187009ac148c833dff5e720a8bb9a717e68
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3784600
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82064}
This very large changeset adds support for RISCV32.
Bug: v8:13025
Change-Id: Ieacc857131e6620f0fcfd7daa88a0f8d77056aa9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3736732
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Yahan Lu <yahan@iscas.ac.cn>
Reviewed-by: ji qiu <qiuji@iscas.ac.cn>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82053}
It was delegating to GetDerivedMap but not handling the possible
error coming from it.
Bug: v8:11111,chromium:1347722
Change-Id: I348ed721281d8edd324f0e364d8ed45602cb9f54
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3791063
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Auto-Submit: Marja Hölttä <marja@chromium.org>
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82046}
This is a reland of commit e895b7af73
The unit test has been updated to work correctly when
--stress-incremental-marking is enabled.
Original change's description:
> Background merging of deserialized scripts
>
> Recently, https://crrev.com/c/v8/v8/+/3681880 added new API functions
> with which an embedder could request that V8 merge newly deserialized
> script data into an existing Script from the Isolate's compilation
> cache. This change implements those new functions. This functionality is
> still disabled by default due to the flag
> merge_background_deserialized_script_with_compilation_cache.
>
> The goal of this new functionality is to reduce memory usage when
> multiple frames load the same script with a long delay between (long
> enough for the script to have been evicted from Blink's in-memory cache
> and for the top-level SharedFunctionInfo to be flushed). In that case,
> there are two Script objects for the same script: one which was found in
> the Isolate compilation cache (the "old" script), and one which was
> recently deserialized (the "new" script). The new script's object graph
> is essentially standalone: it may point to internalized strings and
> readonly objects such as the empty feedback metadata, but otherwise
> it is unconnected to the rest of the heap. The merging logic takes any
> useful data from the new script's object graph and attaches it into the
> old script's object graph, so that the new Script object and any other
> duplicated objects can be discarded. More specifically:
>
> 1. If the new Script has a SharedFunctionInfo for a particular function
> literal, and the old Script does not, then the old Script is updated
> to refer to the new SharedFunctionInfo.
> 2. If the new Script has a compiled SharedFunctionInfo for a particular
> function literal, and the old Script has an uncompiled
> SharedFunctionInfo, then the old SharedFunctionInfo is updated to
> point to the function_data and feedback_metadata from the new
> SharedFunctionInfo.
> 3. If any used object from the new object graph points to a
> SharedFunctionInfo, where the old object graph contains a matching
> SharedFunctionInfo for the same function literal, then that pointer
> is updated to point to the old SharedFunctionInfo.
>
> The document at [0] includes diagrams showing an example merge on a very
> small script.
>
> Steps 1 and 2 above are pretty simple, but step 3 requires walking a
> possibly large set of objects, so this new API lets the embedder run
> step 3 from a background thread. Steps 1 and 2 are performed later, on
> the main thread.
>
> The next important question is: in what ways can the old script's object
> graph be modified during the background execution of step 3, or during
> the time after step 3 but before steps 1 and 2?
>
> A. SharedFunctionInfos can go from compiled to uncompiled due to
> flushing. This is okay; the worst outcome is that the function would
> need to be compiled again later. Such a risk is already present,
> since V8 doesn't keep IsCompiledScopes for every compiled function in
> a background-deserialized script.
> B. SharedFunctionInfos can go from uncompiled to compiled due to lazy
> compilation. This is also okay; the merge completion logic on the
> main thread will just keep this lazily compiled data rather than
> inserting compiled data from the newly deserialized object graph.
> C. SharedFunctionInfos can be cleared from the Script's weak array if
> they are no longer referenced. This is mostly okay, because any
> SharedFunctionInfo that is needed by the background merge is strongly
> referenced and therefore can't be cleared. The only problem arises if
> the top-level SharedFunctionInfo gets cleared, so the merge task must
> deliberately keep a reference to that one.
> D. SharedFunctionInfos can be created if they are needed due to lazy
> compilation of a parent function. This change is somewhat troublesome
> because it invalidates the background thread's work and requires a
> re-traversal on the main thread to update any pointers that should
> point to this lazily compiled SharedFunctionInfo.
>
> At a high level, this change implements three previously unimplemented
> functions in BackgroundDeserializeTask (in compiler.cc) and updates one:
>
> - BackgroundDeserializeTask::SourceTextAvailable, run on the main
> thread, checks whether there is a matching Script in the Isolate
> compilation cache which doesn't already have a top-level
> SharedFunctionInfo. If so, it saves that Script in a persistent
> handle.
> - BackgroundDeserializeTask::ShouldMergeWithExistingScript checks
> whether the persistent handle from the first step exists (a fast
> operation which can be called from any thread).
> - BackgroundDeserializeTask::MergeWithExistingScript, run on a
> background thread, performs step 3 of the merge described above and
> generates lists of persistent data describing how the main thread can
> complete the merge.
> - BackgroundDeserializeTask::Finish is updated to perform the merge
> steps 1 and 2 listed above, as well as a possible re-traversal of the
> graph if required due to newly created SharedFunctionInfos in the old
> Script.
>
> The merge logic has nothing to do with deserialization, and indeed I
> hope to reuse it for background compilation tasks as well, so it is all
> contained within a new class BackgroundMergeTask (in compiler.h,cc). It
> uses a second class, ForwardPointersVisitor (in compiler.cc) to perform
> the object visitation that updates pointers to SharedFunctionInfos.
>
> [0] https://docs.google.com/document/d/1UksB5Vm7TT1-f3S9W1dK_rP9jKn_ly0WVm_UDPpWuBw/edit
>
> Bug: v8:12808
> Change-Id: Id405869e9d5b106ca7afd9c4b08cb5813e6852c6
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3739232
> Reviewed-by: Leszek Swirski <leszeks@chromium.org>
> Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
> Cr-Commit-Position: refs/heads/main@{#81941}
Bug: v8:12808
Change-Id: Id2036dfa4eba8670cac899773d7a906825fa2c50
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3787266
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/main@{#82045}
Memory64 currently does not use trap handling, so we should not allocate
a guard region (10GB total reservation).
This is implemented by adding a {WasmMemoryFlag} enum in the backing
store header, which replaces the previous {MemoryIndexType}. The flag is
not stored with the backing store, as the backing store does not care
about the index type, and we might want to share the same backing store
for memory32 and memory64 (if sizes permit this).
Instead, we (still) store the flag with the WasmMemoryObject and pass it
to the backing store methods.
R=jkummerow@chromium.org
Bug: v8:10949
Change-Id: I284b85b98d181ba5e8d454b24bfa48f6ac201be5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3789506
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82038}
This is a reland of commit 8cb027531c
Original change's description:
> [wasm] Materialize suspender in JS-to-wasm wrapper
>
> Instead of creating the Suspender object in JS and passing it to the
> stack-switching js-to-wasm wrapper, the wrapper now automatically
> creates the Suspender object and forwards it as an extra parameter to
> the wasm function. See:
> https://github.com/WebAssembly/js-promise-integration/pull/1/files
>
> R=ahaas@chromium.org
>
> Bug: v8:12191
> Change-Id: I2badee823f4223a293632f93e7e59f24c49d0820
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3779688
> Commit-Queue: Thibaud Michaud <thibaudm@chromium.org>
> Reviewed-by: Andreas Haas <ahaas@chromium.org>
> Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#81890}
Bug: v8:12191
Change-Id: Iea233e30aa269279d2fe17f5230c87285c33e232
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3780817
Commit-Queue: Thibaud Michaud <thibaudm@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82009}
This CL implements MemoryAllocator::LookupChunkContainingAddress, which
will be used for conservative stack scanning. The method determines
whether an address that may be an inner pointer is contained in some
allocated (normal or large) page. To achieve this, the CL introduces a
page database in the memory allocator.
Bug: v8:12851
Change-Id: I8b719a5f1b6e6b374ccf0666c91c2341c5f9856a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3784986
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Nikolaos Papaspyrou <nikolaos@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82004}
The RTT type can not be used directly in WebAssembly any more and is treated
as a compiler-internal type for the GC MVP.
Bug: v8:7748
Change-Id: I97cb241e6c46446149cc6ae2b1d535b93402fa76
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3787877
Auto-Submit: Matthias Liedtke <mliedtke@chromium.org>
Reviewed-by: Manos Koukoutos <manoskouk@chromium.org>
Commit-Queue: Matthias Liedtke <mliedtke@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82000}
This is a reland of commit 4e935c7ffb
fix a bug on mac for not return correct memory protection key support.
Please see details in comments.
Original change's description:
> [pku][wasm] Refactor PKU usage in Wasm
>
> RwxMemoryWriteScope becomes the bottleneck for both MAP_JIT and PKU
> machinery.
> Wasm and V8 code space will use the same memory protection key.
>
> This is a next step towards adding PKU support for V8 code space.
>
> Bug: v8:13023
> Change-Id: I647f8c09bc41e5ef8a1d74b58a48a43e08454e0d
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3702213
> Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
> Commit-Queue: Wenqin Yang <wenqin.yang@intel.com>
> Reviewed-by: Igor Sheludko <ishell@chromium.org>
> Reviewed-by: Clemens Backes <clemensb@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#81947}
Bug: v8:13023
Change-Id: I5b5cc81e7c1502229ce0d2a5574ca34dc23d19d9
Cq-Include-Trybots: luci.v8.try:v8_mac_arm64_rel_ng,v8_mac_arm64_dbg_ng
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3787320
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Wenqin Yang <wenqin.yang@intel.com>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81994}
Drive-by-fix:
- Rename baseline to sparkplug for consistency
- Add request timeouts for the local symbol server
- Add script to start a local symbol server
- Fix -h/--help support for linux-perf-chrome-renderer-cmd.sh
Change-Id: I4c2fc3595d672871f20fc5c4065ba45e801a1111
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3769699
Auto-Submit: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81992}
After some solid bike shedding, we decided to rename one part of the
API.
R=jarin@chromium.org
Bug: chromium:1334585
Change-Id: Ie967f9f4947b2c328433e4c4a9d748ad15ae7175
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3788095
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Simon Zünd <szuend@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81987}
Remove the range check of formatRange, formatRangeToParts on
NumberFormat and selectRange on PluralRules
Bug: v8:10776
Change-Id: Ifede7d61db6414d5b338b22bd188406e5f7d98b7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3779041
Reviewed-by: Shu-yu Guo <syg@chromium.org>
Commit-Queue: Frank Tang <ftang@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81984}
Call Intl function which call ICU TimeZone for the calculation
of timezone other than UTC
Bug: v8:11544
Change-Id: Idc355aaeccc0bed026a7117bb366ee914fa29733
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3783074
Commit-Queue: Frank Tang <ftang@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81983}
Handle the case where getting a value in the iterable object that
encodes the values throws an exception.
R=ahaas@chromium.org
Bug: chromium:1347073
Change-Id: Ie660ab04148d5fd3508397ae6e08130496f61b74
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3788097
Commit-Queue: Thibaud Michaud <thibaudm@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81974}
The implicit copy constructor triggers a deprecation warning if the
struct contains a deprecated field. We can fix this by explicitly
declaring the copy and move constructors and assignment operators
with the deprecation warning disabled.
This CL also adds a test to check that we can indeed call the
constructors and assignment operators, which did not work before.
R=leszeks@chromium.org
Bug: v8:13092
Change-Id: Ia63ff9375de13fc6e5b5a8d59d827a742c99fb39
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3785145
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81962}
This CL refactors the mechanism for testing the implementation of inner
pointer resolution using the marking bitmap. It allows for more than one
page, where objects can be allocated. It also keeps a list of allocated
objects that are automatically tested.
Bug: v8:12851
Change-Id: I470dc1154aca1ebc3d8526872717747829f83396
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3784605
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Commit-Queue: Nikolaos Papaspyrou <nikolaos@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81952}
The intial version of the API was replaced with a more ergonomic one
recently.
We can also safely remove the test as the new API guarantees that
tasks are always finished and cancelled.
Bug: chromium:1334585
Change-Id: I9ff8b92fcd73ef821c86de52c40a1d04b15ea918
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3780539
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Simon Zünd <szuend@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81950}
This reverts commit 4e935c7ffb.
Reason for revert: Breaking on mac arm64: https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Mac%20-%20arm64%20-%20release/10926/overview
Original change's description:
> [pku][wasm] Refactor PKU usage in Wasm
>
> RwxMemoryWriteScope becomes the bottleneck for both MAP_JIT and PKU
> machinery.
> Wasm and V8 code space will use the same memory protection key.
>
> This is a next step towards adding PKU support for V8 code space.
>
> Bug: v8:13023
> Change-Id: I647f8c09bc41e5ef8a1d74b58a48a43e08454e0d
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3702213
> Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
> Commit-Queue: Wenqin Yang <wenqin.yang@intel.com>
> Reviewed-by: Igor Sheludko <ishell@chromium.org>
> Reviewed-by: Clemens Backes <clemensb@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#81947}
Bug: v8:13023
Change-Id: I11c52ac101804ab75b1bb1d4814f083cb1083d5b
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3780498
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Owners-Override: Leszek Swirski <leszeks@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#81949}
RwxMemoryWriteScope becomes the bottleneck for both MAP_JIT and PKU
machinery.
Wasm and V8 code space will use the same memory protection key.
This is a next step towards adding PKU support for V8 code space.
Bug: v8:13023
Change-Id: I647f8c09bc41e5ef8a1d74b58a48a43e08454e0d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3702213
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Wenqin Yang <wenqin.yang@intel.com>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81947}
This reverts commit e895b7af73.
Reason for revert: TSAN failures: https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Linux64%20TSAN%20-%20stress-incremental-marking/8468/overview
Original change's description:
> Background merging of deserialized scripts
>
> Recently, https://crrev.com/c/v8/v8/+/3681880 added new API functions
> with which an embedder could request that V8 merge newly deserialized
> script data into an existing Script from the Isolate's compilation
> cache. This change implements those new functions. This functionality is
> still disabled by default due to the flag
> merge_background_deserialized_script_with_compilation_cache.
>
> The goal of this new functionality is to reduce memory usage when
> multiple frames load the same script with a long delay between (long
> enough for the script to have been evicted from Blink's in-memory cache
> and for the top-level SharedFunctionInfo to be flushed). In that case,
> there are two Script objects for the same script: one which was found in
> the Isolate compilation cache (the "old" script), and one which was
> recently deserialized (the "new" script). The new script's object graph
> is essentially standalone: it may point to internalized strings and
> readonly objects such as the empty feedback metadata, but otherwise
> it is unconnected to the rest of the heap. The merging logic takes any
> useful data from the new script's object graph and attaches it into the
> old script's object graph, so that the new Script object and any other
> duplicated objects can be discarded. More specifically:
>
> 1. If the new Script has a SharedFunctionInfo for a particular function
> literal, and the old Script does not, then the old Script is updated
> to refer to the new SharedFunctionInfo.
> 2. If the new Script has a compiled SharedFunctionInfo for a particular
> function literal, and the old Script has an uncompiled
> SharedFunctionInfo, then the old SharedFunctionInfo is updated to
> point to the function_data and feedback_metadata from the new
> SharedFunctionInfo.
> 3. If any used object from the new object graph points to a
> SharedFunctionInfo, where the old object graph contains a matching
> SharedFunctionInfo for the same function literal, then that pointer
> is updated to point to the old SharedFunctionInfo.
>
> The document at [0] includes diagrams showing an example merge on a very
> small script.
>
> Steps 1 and 2 above are pretty simple, but step 3 requires walking a
> possibly large set of objects, so this new API lets the embedder run
> step 3 from a background thread. Steps 1 and 2 are performed later, on
> the main thread.
>
> The next important question is: in what ways can the old script's object
> graph be modified during the background execution of step 3, or during
> the time after step 3 but before steps 1 and 2?
>
> A. SharedFunctionInfos can go from compiled to uncompiled due to
> flushing. This is okay; the worst outcome is that the function would
> need to be compiled again later. Such a risk is already present,
> since V8 doesn't keep IsCompiledScopes for every compiled function in
> a background-deserialized script.
> B. SharedFunctionInfos can go from uncompiled to compiled due to lazy
> compilation. This is also okay; the merge completion logic on the
> main thread will just keep this lazily compiled data rather than
> inserting compiled data from the newly deserialized object graph.
> C. SharedFunctionInfos can be cleared from the Script's weak array if
> they are no longer referenced. This is mostly okay, because any
> SharedFunctionInfo that is needed by the background merge is strongly
> referenced and therefore can't be cleared. The only problem arises if
> the top-level SharedFunctionInfo gets cleared, so the merge task must
> deliberately keep a reference to that one.
> D. SharedFunctionInfos can be created if they are needed due to lazy
> compilation of a parent function. This change is somewhat troublesome
> because it invalidates the background thread's work and requires a
> re-traversal on the main thread to update any pointers that should
> point to this lazily compiled SharedFunctionInfo.
>
> At a high level, this change implements three previously unimplemented
> functions in BackgroundDeserializeTask (in compiler.cc) and updates one:
>
> - BackgroundDeserializeTask::SourceTextAvailable, run on the main
> thread, checks whether there is a matching Script in the Isolate
> compilation cache which doesn't already have a top-level
> SharedFunctionInfo. If so, it saves that Script in a persistent
> handle.
> - BackgroundDeserializeTask::ShouldMergeWithExistingScript checks
> whether the persistent handle from the first step exists (a fast
> operation which can be called from any thread).
> - BackgroundDeserializeTask::MergeWithExistingScript, run on a
> background thread, performs step 3 of the merge described above and
> generates lists of persistent data describing how the main thread can
> complete the merge.
> - BackgroundDeserializeTask::Finish is updated to perform the merge
> steps 1 and 2 listed above, as well as a possible re-traversal of the
> graph if required due to newly created SharedFunctionInfos in the old
> Script.
>
> The merge logic has nothing to do with deserialization, and indeed I
> hope to reuse it for background compilation tasks as well, so it is all
> contained within a new class BackgroundMergeTask (in compiler.h,cc). It
> uses a second class, ForwardPointersVisitor (in compiler.cc) to perform
> the object visitation that updates pointers to SharedFunctionInfos.
>
> [0] https://docs.google.com/document/d/1UksB5Vm7TT1-f3S9W1dK_rP9jKn_ly0WVm_UDPpWuBw/edit
>
> Bug: v8:12808
> Change-Id: Id405869e9d5b106ca7afd9c4b08cb5813e6852c6
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3739232
> Reviewed-by: Leszek Swirski <leszeks@chromium.org>
> Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
> Cr-Commit-Position: refs/heads/main@{#81941}
Bug: v8:12808
Change-Id: I82a080e6287828445293cb6b4b94a5e8f15eb8f3
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3787213
Auto-Submit: Deepti Gandluri <gdeepti@chromium.org>
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Owners-Override: Deepti Gandluri <gdeepti@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#81943}
Recently, https://crrev.com/c/v8/v8/+/3681880 added new API functions
with which an embedder could request that V8 merge newly deserialized
script data into an existing Script from the Isolate's compilation
cache. This change implements those new functions. This functionality is
still disabled by default due to the flag
merge_background_deserialized_script_with_compilation_cache.
The goal of this new functionality is to reduce memory usage when
multiple frames load the same script with a long delay between (long
enough for the script to have been evicted from Blink's in-memory cache
and for the top-level SharedFunctionInfo to be flushed). In that case,
there are two Script objects for the same script: one which was found in
the Isolate compilation cache (the "old" script), and one which was
recently deserialized (the "new" script). The new script's object graph
is essentially standalone: it may point to internalized strings and
readonly objects such as the empty feedback metadata, but otherwise
it is unconnected to the rest of the heap. The merging logic takes any
useful data from the new script's object graph and attaches it into the
old script's object graph, so that the new Script object and any other
duplicated objects can be discarded. More specifically:
1. If the new Script has a SharedFunctionInfo for a particular function
literal, and the old Script does not, then the old Script is updated
to refer to the new SharedFunctionInfo.
2. If the new Script has a compiled SharedFunctionInfo for a particular
function literal, and the old Script has an uncompiled
SharedFunctionInfo, then the old SharedFunctionInfo is updated to
point to the function_data and feedback_metadata from the new
SharedFunctionInfo.
3. If any used object from the new object graph points to a
SharedFunctionInfo, where the old object graph contains a matching
SharedFunctionInfo for the same function literal, then that pointer
is updated to point to the old SharedFunctionInfo.
The document at [0] includes diagrams showing an example merge on a very
small script.
Steps 1 and 2 above are pretty simple, but step 3 requires walking a
possibly large set of objects, so this new API lets the embedder run
step 3 from a background thread. Steps 1 and 2 are performed later, on
the main thread.
The next important question is: in what ways can the old script's object
graph be modified during the background execution of step 3, or during
the time after step 3 but before steps 1 and 2?
A. SharedFunctionInfos can go from compiled to uncompiled due to
flushing. This is okay; the worst outcome is that the function would
need to be compiled again later. Such a risk is already present,
since V8 doesn't keep IsCompiledScopes for every compiled function in
a background-deserialized script.
B. SharedFunctionInfos can go from uncompiled to compiled due to lazy
compilation. This is also okay; the merge completion logic on the
main thread will just keep this lazily compiled data rather than
inserting compiled data from the newly deserialized object graph.
C. SharedFunctionInfos can be cleared from the Script's weak array if
they are no longer referenced. This is mostly okay, because any
SharedFunctionInfo that is needed by the background merge is strongly
referenced and therefore can't be cleared. The only problem arises if
the top-level SharedFunctionInfo gets cleared, so the merge task must
deliberately keep a reference to that one.
D. SharedFunctionInfos can be created if they are needed due to lazy
compilation of a parent function. This change is somewhat troublesome
because it invalidates the background thread's work and requires a
re-traversal on the main thread to update any pointers that should
point to this lazily compiled SharedFunctionInfo.
At a high level, this change implements three previously unimplemented
functions in BackgroundDeserializeTask (in compiler.cc) and updates one:
- BackgroundDeserializeTask::SourceTextAvailable, run on the main
thread, checks whether there is a matching Script in the Isolate
compilation cache which doesn't already have a top-level
SharedFunctionInfo. If so, it saves that Script in a persistent
handle.
- BackgroundDeserializeTask::ShouldMergeWithExistingScript checks
whether the persistent handle from the first step exists (a fast
operation which can be called from any thread).
- BackgroundDeserializeTask::MergeWithExistingScript, run on a
background thread, performs step 3 of the merge described above and
generates lists of persistent data describing how the main thread can
complete the merge.
- BackgroundDeserializeTask::Finish is updated to perform the merge
steps 1 and 2 listed above, as well as a possible re-traversal of the
graph if required due to newly created SharedFunctionInfos in the old
Script.
The merge logic has nothing to do with deserialization, and indeed I
hope to reuse it for background compilation tasks as well, so it is all
contained within a new class BackgroundMergeTask (in compiler.h,cc). It
uses a second class, ForwardPointersVisitor (in compiler.cc) to perform
the object visitation that updates pointers to SharedFunctionInfos.
[0] https://docs.google.com/document/d/1UksB5Vm7TT1-f3S9W1dK_rP9jKn_ly0WVm_UDPpWuBw/edit
Bug: v8:12808
Change-Id: Id405869e9d5b106ca7afd9c4b08cb5813e6852c6
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3739232
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/main@{#81941}
