The ExternalPointerTags are assumed to be compile-time constants in most
cases, so turning them into template parameters enforces that. As
decisions such as whether to use the per-isolate or the shared external
pointer table are encoded into the tag values, forcing those to be
compile-time constants guarantees that the compiler will be able to
inline the correct logic when accessing an external pointer.
With this, there are now two (high-level) ways of accessing external pointer fields from C++: the Read/WriteExternalPointerField methods
which require the ExternalPointerTag to be a template parameter, and the
ExternalPointerSlot class which takes the tag as an argument. The latter
is for example used for snapshot deserialization and by the garbage
collector (more generally, by the ObjectVisitor::VisitExternalPointer
method), where the tag is not a compile-time constant.
Finally, this CL also introduces a new ExternalPointerHandle type which
represents the (opaque) on-heap representation of a reference to an
entry in an ExternalPointerTable when sandboxing is enabled. Making this
its own type makes the code a bit more readable.
Bug: v8:10391
Change-Id: I867b8ce41d15d485f1dc66786f233c710c56afcb
Cq-Include-Trybots: luci.v8.try:v8_linux64_heap_sandbox_dbg_ng,v8_linux_arm64_sim_heap_sandbox_dbg_ng
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3720641
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Samuel Groß <saelo@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81402}
Now that we require C++17 support, we can just use the standard
static_assert without message, instead of our STATIC_ASSERT macro.
R=leszeks@chromium.org
Bug: v8:12425
Change-Id: I1d4e39c310b533bcd3a4af33d027827e6c083afe
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3647353
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80524}
Now that we are able to compact map space, we can also get rid of the
map space and allocate maps in the old space instead. This CL introduces
a FLAG_map_space for enabling/disabling the map space but the map space
remains enabled by default for now.
Without a separate space for maps, the GC can't prevent relocation of
maps anymore. Therefore this CL always allows compaction of maps when
running without a map space. Rename flag to --compact-maps to better fit
this scenario.
mkgrokdump and debug_helper also need to be updated to look for maps
also in the old space. The map space is now optional.
Bug: v8:12578
Change-Id: Ic4e4abd0b58bee26e64329b1c92dbccb07d8105a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3424483
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Seth Brenith <seth.brenith@microsoft.com>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79165}
This is a reland of 517ed4ad00
Original change's description:
> Reland "[Torque] Generalize Torque literals to larger size"
>
> Previously, literals in Torque were stored as double values, which
> made it impossible to precisely represent 64 bit integer values.
> This CL replaces the old literal expression with an integer and
> floating point literal expression that are unbounded in size. We
> allow implicit conversion of these literals to arbitary integer
> and floating point types respectively and insert a corresponding
> bounds check into generated CSA.
>
> Changes in the reland: Simplified IntegerLiteral to single digit.
>
> Bug: v8:7793, chromium:1289282
> Change-Id: I31c762c2f31165c7a1d0b07842b764e5851ce189
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3406750
> Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
> Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
> Commit-Queue: Nico Hartmann <nicohartmann@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#78811}
Bug: v8:7793, chromium:1289282
Change-Id: I7aadc4d2c9494f03eae85e94949c8f4cab7a075c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3437047
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Nico Hartmann <nicohartmann@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78939}
This reverts commit 517ed4ad00.
Reason for revert: There still seems to be an issue on V8 Win msvc related to this CL (https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Win64%20-%20msvc/20568/overview).
Original change's description:
> Reland "[Torque] Generalize Torque literals to larger size"
>
> Previously, literals in Torque were stored as double values, which
> made it impossible to precisely represent 64 bit integer values.
> This CL replaces the old literal expression with an integer and
> floating point literal expression that are unbounded in size. We
> allow implicit conversion of these literals to arbitary integer
> and floating point types respectively and insert a corresponding
> bounds check into generated CSA.
>
> Changes in the reland: Simplified IntegerLiteral to single digit.
>
> Bug: v8:7793, chromium:1289282
> Change-Id: I31c762c2f31165c7a1d0b07842b764e5851ce189
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3406750
> Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
> Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
> Commit-Queue: Nico Hartmann <nicohartmann@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#78811}
Bug: v8:7793, chromium:1289282
Change-Id: I818cec9625fbd827a4a30088d8c8b759fb6c50d7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3424484
Owners-Override: Nico Hartmann <nicohartmann@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Nico Hartmann <nicohartmann@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78847}
- It changes ContextSlotIndex from static to non-static.
- Updates ContextSlotIndex and ScriptContextTable::Lookup to use
handles, since it is necessary for the NameToIndexHashTable::Add
- Adds a NameToIndexHashTableLookup to CSA.
- Renames LocalNamesIterator to LocalNamesRange and iterates the
hashtable when local names are not inlined.
Bug: v8:12315
Change-Id: I2c8c933002fe73f4def145bc207825823262d743
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3406751
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Victor Gomes <victorgomes@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78818}
Previously, literals in Torque were stored as double values, which
made it impossible to precisely represent 64 bit integer values.
This CL replaces the old literal expression with an integer and
floating point literal expression that are unbounded in size. We
allow implicit conversion of these literals to arbitary integer
and floating point types respectively and insert a corresponding
bounds check into generated CSA.
Changes in the reland: Simplified IntegerLiteral to single digit.
Bug: v8:7793, chromium:1289282
Change-Id: I31c762c2f31165c7a1d0b07842b764e5851ce189
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3406750
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Nico Hartmann <nicohartmann@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78811}
This reverts commit 757830b02b.
Reason for revert: Speculatively revert due to a number of
performance regressions
Original change's description:
> [Torque] Generalize Torque literals to larger size
>
> Previously, literals in Torque were stored as double values, which
> made it impossible to precisely represent 64 bit integer values.
> This CL replaces the old literal expression with an integer and
> floating point literal expression that are unbounded in size. We
> allow implicit conversion of these literals to arbitary integer
> and floating point types respectively and insert a corresponding
> bounds check into generated CSA.
>
> Bug: v8:7793
> Change-Id: I46c231aab92bc2f0c26955d1876079f306b358c6
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3329792
> Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
> Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
> Commit-Queue: Nico Hartmann <nicohartmann@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#78671}
Bug: v8:7793
Change-Id: I9896e28b3c69b8cf2488bf93e993ec320d8c5d2e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3401866
Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Owners-Override: Nico Hartmann <nicohartmann@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Nico Hartmann <nicohartmann@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78706}
Previously, literals in Torque were stored as double values, which
made it impossible to precisely represent 64 bit integer values.
This CL replaces the old literal expression with an integer and
floating point literal expression that are unbounded in size. We
allow implicit conversion of these literals to arbitary integer
and floating point types respectively and insert a corresponding
bounds check into generated CSA.
Bug: v8:7793
Change-Id: I46c231aab92bc2f0c26955d1876079f306b358c6
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3329792
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Nico Hartmann <nicohartmann@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78671}
kScopeInfoMaxInlinedLocalNamesSize is a threshold for inlined storage,
otherwise local names will be stored in a hash table.
Bug: v8:12315
Change-Id: Ibfa5bec5222c9e60765c3663707623544895ec0f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3386601
Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Commit-Queue: Victor Gomes <victorgomes@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78622}
This CL renames a number of things related to the V8 sandbox.
Mainly, what used to be under V8_HEAP_SANDBOX is now under
V8_SANDBOXED_EXTERNAL_POINTERS, while the previous V8 VirtualMemoryCage
is now simply the V8 Sandbox:
V8_VIRTUAL_MEMORY_CAGE => V8_SANDBOX
V8_HEAP_SANDBOX => V8_SANDBOXED_EXTERNAL_POINTERS
V8_CAGED_POINTERS => V8_SANDBOXED_POINTERS
V8VirtualMemoryCage => Sandbox
CagedPointer => SandboxedPointer
fake cage => partially reserved sandbox
src/security => src/sandbox
This naming scheme should simplify things: the sandbox is now the large
region of virtual address space inside which V8 mainly operates and
which should be considered untrusted. Mechanisms like sandboxed pointers
are then used to attempt to prevent escapes from the sandbox (i.e.
corruption of memory outside of it). Furthermore, the new naming scheme
avoids the confusion with the various other "cages" in V8, in
particular, the VirtualMemoryCage class, by dropping that name entirely.
Future sandbox features are developed under their own V8_SANDBOX_X flag,
and will, once final, be merged into V8_SANDBOX. Current future features
are sandboxed external pointers (using the external pointer table), and
sandboxed pointers (pointers guaranteed to point into the sandbox, e.g.
because they are encoded as offsets). This CL then also introduces a new
build flag, v8_enable_sandbox_future, which enables all future features.
Bug: v8:10391
Change-Id: I5174ea8f5ab40fb96a04af10853da735ad775c96
Cq-Include-Trybots: luci.v8.try:v8_linux64_heap_sandbox_dbg_ng,v8_linux_arm64_sim_heap_sandbox_dbg_ng
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3322981
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Samuel Groß <saelo@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78384}
I've noticed a few places where class fields as defined in Torque have
different names than the corresponding accessors in the C++ class. I
think they should match. Most of this change is just mechanically
updating the various places that use k##Field##Offset for those fields.
Change-Id: I8ba52aed7f6a1cd6b2d71158f71150b66c2c0da0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3027263
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75796}
This CL adds features to pack/unpack map words.
Currently V8 cannot store extra metadata in object headers -- because V8
objects do not have a proper header, but only a map pointer at the start
of the object. To store per-object metadata like marking data, a side
table is required as the per-object metadata storage.
This CL enables V8 to use higher unused bits in a 64-bit map word as
per-object metadata storage. Map pointer stores come with an extra step
to encode the metadata into the pointer (we call it "map packing").
Map pointer loads will also remove the metadata bits as well (we call it
"map packing").
Since the map word is no longer a valid pointer after packing, we also
change the tag of the packed map word to make it looks like a Smi. This
helps various GC and barrier code to correctly skip them instead of
blindly dereferencing this invalid pointer.
A ninja flag `v8_enable_map_packing` is provided to turn this
map-packing feature on and off. It is disabled by default.
* Only works on x64 platform, with `v8_enable_pointer_compression`
set to `false`
Bug: v8:11624
Change-Id: Ia2bdf79553945e5fc0b0874c87803d2cc733e073
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2247561
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73915}
This removes the heap sandbox's dependency on being able to reconstruct
an Isolate from the pointer cage base address.
Bug: v8:11460
Change-Id: I501ace5b83a2cefdf717de0d7387fd816edfb3f1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2783673
Auto-Submit: Shu-yu Guo <syg@chromium.org>
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Deepti Gandluri <gdeepti@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73887}
This is a reland of e28dadc207
The original failure was due to a stale Win32 bot. The reland failure
was due to idempotent task deduplication returning the exact same
failure. See crbug/1196064
Original change's description:
> [ptr-cage] Rename IsolateRoot to PtrComprCageBase
>
> Currently, IsolateRoot is both the address of the Isolate root and the
> base address of the pointer compression reservation. This CL teases the
> two uses apart by renaming IsolateRoot to PtrComprCageBase.
>
> - In addition to V8_COMPRESS_POINTERS, add a
> V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE (vs SHARED_CAGE).
>
> - Rename GetIsolate* helpers to GetPtrComprCageBase. When
> V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE is true, the helpers remain as
> aliases to GetPtrComprCageBase.
>
> - Rename kPtrComprIsolateRootAlignment to kPtrComprCageBaseAlignment.
>
> Bug: v8:11460
> Change-Id: I1d715f678ce9a0b5731895612ca14f56579b1c48
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2783672
> Commit-Queue: Shu-yu Guo <syg@chromium.org>
> Auto-Submit: Shu-yu Guo <syg@chromium.org>
> Reviewed-by: Igor Sheludko <ishell@chromium.org>
> Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#73790}
Bug: v8:11460
No-Try: true
Tbr: ishell@chromium.org
Tbr: rmcilroy@chromium.org
Change-Id: Id69311cf3267ebe1297fff159de0be48b15b65a3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2806546
Reviewed-by: Shu-yu Guo <syg@chromium.org>
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73795}
This reverts commit 15c78b45a6.
Reason for revert: https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Win32/32277/overview
Original change's description:
> Reland "[ptr-cage] Rename IsolateRoot to PtrComprCageBase"
>
> This is a reland of e28dadc207
>
> Relanding to see if Win32 rel failures from
> https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Win32/32275/overview
> were infra flakes. Could not repro on try bots.
>
> Original change's description:
> > [ptr-cage] Rename IsolateRoot to PtrComprCageBase
> >
> > Currently, IsolateRoot is both the address of the Isolate root and the
> > base address of the pointer compression reservation. This CL teases the
> > two uses apart by renaming IsolateRoot to PtrComprCageBase.
> >
> > - In addition to V8_COMPRESS_POINTERS, add a
> > V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE (vs SHARED_CAGE).
> >
> > - Rename GetIsolate* helpers to GetPtrComprCageBase. When
> > V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE is true, the helpers remain as
> > aliases to GetPtrComprCageBase.
> >
> > - Rename kPtrComprIsolateRootAlignment to kPtrComprCageBaseAlignment.
> >
> > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2783672
> > Reviewed-by: Igor Sheludko <ishell@chromium.org>
> > Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
>
> No-Try: true
> Bug: v8:11460
> Tbr: ishell@chromium.org
> Tbr: rmcilroy@chromium.org
> Change-Id: I0a8c3a48999d6737c8c64d2c2703607f14f3fdd0
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2806169
> Reviewed-by: Shu-yu Guo <syg@chromium.org>
> Commit-Queue: Shu-yu Guo <syg@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#73792}
Bug: v8:11460
Change-Id: Ifee92d622c43a91c15f45ef94ff739237bd2024b
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2806545
Auto-Submit: Shu-yu Guo <syg@chromium.org>
Reviewed-by: Shu-yu Guo <syg@chromium.org>
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73793}
This is a reland of e28dadc207
Relanding to see if Win32 rel failures from
https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Win32/32275/overview
were infra flakes. Could not repro on try bots.
Original change's description:
> [ptr-cage] Rename IsolateRoot to PtrComprCageBase
>
> Currently, IsolateRoot is both the address of the Isolate root and the
> base address of the pointer compression reservation. This CL teases the
> two uses apart by renaming IsolateRoot to PtrComprCageBase.
>
> - In addition to V8_COMPRESS_POINTERS, add a
> V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE (vs SHARED_CAGE).
>
> - Rename GetIsolate* helpers to GetPtrComprCageBase. When
> V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE is true, the helpers remain as
> aliases to GetPtrComprCageBase.
>
> - Rename kPtrComprIsolateRootAlignment to kPtrComprCageBaseAlignment.
>
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2783672
> Reviewed-by: Igor Sheludko <ishell@chromium.org>
> Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
No-Try: true
Bug: v8:11460
Tbr: ishell@chromium.org
Tbr: rmcilroy@chromium.org
Change-Id: I0a8c3a48999d6737c8c64d2c2703607f14f3fdd0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2806169
Reviewed-by: Shu-yu Guo <syg@chromium.org>
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73792}
This reverts commit e28dadc207.
Reason for revert: failed test262 tests;; see https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Win32/32275/steps?succeeded=true&debug=false
Original change's description:
> [ptr-cage] Rename IsolateRoot to PtrComprCageBase
>
> Currently, IsolateRoot is both the address of the Isolate root and the
> base address of the pointer compression reservation. This CL teases the
> two uses apart by renaming IsolateRoot to PtrComprCageBase.
>
> - In addition to V8_COMPRESS_POINTERS, add a
> V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE (vs SHARED_CAGE).
>
> - Rename GetIsolate* helpers to GetPtrComprCageBase. When
> V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE is true, the helpers remain as
> aliases to GetPtrComprCageBase.
>
> - Rename kPtrComprIsolateRootAlignment to kPtrComprCageBaseAlignment.
>
> Bug: v8:11460
> Change-Id: I1d715f678ce9a0b5731895612ca14f56579b1c48
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2783672
> Commit-Queue: Shu-yu Guo <syg@chromium.org>
> Auto-Submit: Shu-yu Guo <syg@chromium.org>
> Reviewed-by: Igor Sheludko <ishell@chromium.org>
> Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#73790}
Bug: v8:11460
Change-Id: I19d0e28194fcdb28e89f129a7694ca3fe29fa17a
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2806168
Auto-Submit: Francis McCabe <fgm@chromium.org>
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#73791}
Currently, IsolateRoot is both the address of the Isolate root and the
base address of the pointer compression reservation. This CL teases the
two uses apart by renaming IsolateRoot to PtrComprCageBase.
- In addition to V8_COMPRESS_POINTERS, add a
V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE (vs SHARED_CAGE).
- Rename GetIsolate* helpers to GetPtrComprCageBase. When
V8_COMPRESS_POINTERS_IN_ISOLATE_CAGE is true, the helpers remain as
aliases to GetPtrComprCageBase.
- Rename kPtrComprIsolateRootAlignment to kPtrComprCageBaseAlignment.
Bug: v8:11460
Change-Id: I1d715f678ce9a0b5731895612ca14f56579b1c48
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2783672
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Auto-Submit: Shu-yu Guo <syg@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73790}
This is a reland of 19b62d0b4e
Fixing the misalignment issue founded in usban build by doing four-byte
comparison: compressing the "expected" values such as script.name() and
passing them to CheckProp as type Tagged_t
Original change's description:
> [v8windbg] Add more items in the Locals pane
>
> Add more items in the Locals pane representing the JS function name,
> source file name, and character offset within the source file, so
> that the user doesn’t need to dig through the shared_function_info to
> find them.
>
> Change-Id: I5d42b3c9542885a72e81613503d1d5abf51870b5
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2712310
> Commit-Queue: Z Nguyen-Huu <duongn@microsoft.com>
> Reviewed-by: Seth Brenith <seth.brenith@microsoft.com>
> Cr-Commit-Position: refs/heads/master@{#73282}
Change-Id: Idd77f61905651fbcfae5f5b590094639bc205834
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2744959
Reviewed-by: Seth Brenith <seth.brenith@microsoft.com>
Commit-Queue: Z Nguyen-Huu <duongn@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#73359}
This reverts commit 19b62d0b4e.
Reason for revert: Undefined behavior
https://ci.chromium.org/p/v8/builders/ci/V8%20Linux64%20UBSan/15449
Original change's description:
> [v8windbg] Add more items in the Locals pane
>
> Add more items in the Locals pane representing the JS function name,
> source file name, and character offset within the source file, so
> that the user doesn’t need to dig through the shared_function_info to
> find them.
>
> Change-Id: I5d42b3c9542885a72e81613503d1d5abf51870b5
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2712310
> Commit-Queue: Z Nguyen-Huu <duongn@microsoft.com>
> Reviewed-by: Seth Brenith <seth.brenith@microsoft.com>
> Cr-Commit-Position: refs/heads/master@{#73282}
Change-Id: I616cd642379b97dff5fb0c66aeb6488e2f9b298b
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2744420
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Reviewed-by: Bill Budge <bbudge@chromium.org>
Commit-Queue: Bill Budge <bbudge@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73284}
Add more items in the Locals pane representing the JS function name,
source file name, and character offset within the source file, so
that the user doesn’t need to dig through the shared_function_info to
find them.
Change-Id: I5d42b3c9542885a72e81613503d1d5abf51870b5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2712310
Commit-Queue: Z Nguyen-Huu <duongn@microsoft.com>
Reviewed-by: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#73282}
Split out all the headers from v8_compiler/v8_compiler_opt and
v8_base_without_compiler into v8_internal_headers since the headers
have inter-dependencies that otherwise make it impossible to satisfy gn
check.
Also adds new v8_header_set torque_runtime_support that exports
src/torque/runtime-support.h separately from the generated headers.
This reduces the number of gn check failures from 169 to 59.
Bug: v8:7330
Change-Id: Ie7ebc894910b7efa02011a74da964e11995c7f4f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2712569
Commit-Queue: Dan Elphick <delphick@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73104}
Currently if gn check is enabled (with v8/third_party ignored), there
are many errors due to headers being used without adding the proper
dependency in BUILD.gn (or because it's being used transitively without
a public_deps chain).
This makes the number of errors go from 2114 to 195.
Apart from adding dependencies, it also moves _v8_internal_Node_Print
from objects-printer.cc to node.cc so it can see the Node::Print method
which wouldn't otherwise be possible without a circular dependency. Also
removes the previously deleted compiler/graph-builder-tester.h file.
Bug: v8:7330
Change-Id: Icb34585fbef621588265cf4267cfc88ecbcf0a72
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2702331
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72908}
This change adds Torque field definitions for ScopeInfo and begins to
use the Torque-generated accessors in some places. It does not change
the in-memory layout of ScopeInfo.
Torque compiler changes:
- Fix an issue where the parser created constexpr types for classes
based on the class name rather than the `generates` clause. This meant
that generated accessors referred to the imaginary type HashTable
rather than the real C++ type FixedArray.
- Don't pass Isolate* through the generated runtime functions that
implement Torque macros. Maybe we'll need it eventually, but we don't
right now and it complicates a lot of things.
- Don't emit `kSomeFieldOffset` if some_field has an unknown offset.
Instead, emit a member function `SomeFieldOffset()` which fetches the
slice for some_field and returns its offset.
- Emit an `AllocatedSize()` member function for classes which have
complex length expressions. It fetches the slice for the last field
and performs the multiply&add to compute the total object size.
- Emit field accessors for fields with complex length expressions, using
the new offset functions.
- Fix a few minor bugs where Torque can write uncompilable code.
With this change, most code still treats ScopeInfo like a FixedArray, so
I would like to follow up with some additional changes:
1. Generate a GC visitor for ScopeInfo and use it
2. Generate accessors for struct-typed fields (indexed or otherwise),
and use them
3. Get rid of the FixedArray-style get and set accessors; use
TaggedField::load and similar instead
4. Inherit from HeapObject rather than FixedArrayBase to remove the
unnecessary `length` field
After that, there will only be one ugly part left: initialization. I
think it's possible to generate a factory function that takes a bunch of
iterator parameters and returns a fully-formed, verifiably correct
ScopeInfo instance, but doing so is more complicated than the four
mostly-mechanical changes listed above.
Bug: v8:7793
Change-Id: I55fcfe9189e4d1613c68d49e378da5dc02597b36
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2357758
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#72187}
Docs: https://docs.google.com/document/d/13n1qaB6A-gvgWc9NDhWm-UPuOqow_Y0DNgCeTbtIotI
Modify that C++ backend so that it can emit either runtime C++ or
postmortem debugging code. When in postmortem debugging mode, the
overall code structure would look similar with some difference:
1. Instead of passing an Isolate* everywhere, we pass a MemoryAccessor.
2. Instead of runtime class names like String, we use uintptr_t
3. When loading data from objects, instead of TaggedField<T>::load or
Object::ReadField (which read from the current process), we use the
MemoryAccessor and read data from the debuggee process.
4. Return values should be wrapped in the Value struct.
Implement the debug accessors for complex length expressions and add
test for such class (SmallOrderedHashSet).
Change-Id: I34107c92b31ed4e07bb628ae58c84487e41ba648
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2477921
Commit-Queue: Z Nguyen-Huu <duongn@microsoft.com>
Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#72148}
This change tags pointers in the external pointer table with a type
dependent value in order to prevent type confusions between different
external pointers.
Bug: v8:10391
Change-Id: I5a83178e5ac46d49a99c91047816926120d801d3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2443133
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Samuel Groß <saelo@google.com>
Cr-Commit-Position: refs/heads/master@{#70430}
Introduce an IsolateRoot class, which encapsulates the root address
needed for pointer decompression. This class is implicitly constructible
from both Isolate* and LocalIsolate*, allowing us to avoid templating
methods that can take both, or awkwardly creating a `const Isolate*`
from a `LocalIsolate*` just for getters.
Change-Id: I6d4b9492409fc7d5b375162e381192cb48c8ba01
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2440605
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70365}
This is a reland of 64caf2b0b2
Original change's description:
> [torque] refactor: use -tq only in filenames derived from .tq files
>
> This is to establish a naming rule for Torque-generated files:
> - If the file is called foo/bar-tq..., then it is derived from a
> file foo/bar.tq
> - Otherwise it doesn't belong to a specific .tq file.
>
> So far, we attached -tq to all Torque-generated file names, where it
> sometimes corresponded to a .tq file name and sometimes not.
> It is not necessary to add -tq to file names to indicate that they are
> Torque-generated, since they are already in a directory called
> torque-generated, and we always refer to them as
> "torque-generated/filename", so there is no confusion even though some
> files now have the same name as a corresponding hand-written file, for
> example factory.cc.
>
> TBR: hpayer@chromium.org
> Bug: v8:7793
> Change-Id: Ie172babad1fc7422fd1059c48f5dafaa53e50c8b
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2414218
> Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#70060}
Bug: v8:7793
TBR: hpayer@chromium.orgjgruber@chromium.org
Change-Id: I6c492bc64aee1ff167e7ef401825eca9097a7f38
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2431565
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70137}
This reverts commit 64caf2b0b2.
Reason for revert: Seems to be causing a failure:
https://ci.chromium.org/p/v8/builders/ci/V8%20Linux/38809?
Original change's description:
> [torque] refactor: use -tq only in filenames derived from .tq files
>
> This is to establish a naming rule for Torque-generated files:
> - If the file is called foo/bar-tq..., then it is derived from a
> file foo/bar.tq
> - Otherwise it doesn't belong to a specific .tq file.
>
> So far, we attached -tq to all Torque-generated file names, where it
> sometimes corresponded to a .tq file name and sometimes not.
> It is not necessary to add -tq to file names to indicate that they are
> Torque-generated, since they are already in a directory called
> torque-generated, and we always refer to them as
> "torque-generated/filename", so there is no confusion even though some
> files now have the same name as a corresponding hand-written file, for
> example factory.cc.
>
> TBR: hpayer@chromium.org
> Bug: v8:7793
> Change-Id: Ie172babad1fc7422fd1059c48f5dafaa53e50c8b
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2414218
> Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#70060}
TBR=jgruber@chromium.org,tebbi@chromium.org
Change-Id: I6960fe540861947536c6ddfc0f4887ea80899fae
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:7793
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2424486
Reviewed-by: Francis McCabe <fgm@chromium.org>
Commit-Queue: Francis McCabe <fgm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70065}
This is to establish a naming rule for Torque-generated files:
- If the file is called foo/bar-tq..., then it is derived from a
file foo/bar.tq
- Otherwise it doesn't belong to a specific .tq file.
So far, we attached -tq to all Torque-generated file names, where it
sometimes corresponded to a .tq file name and sometimes not.
It is not necessary to add -tq to file names to indicate that they are
Torque-generated, since they are already in a directory called
torque-generated, and we always refer to them as
"torque-generated/filename", so there is no confusion even though some
files now have the same name as a corresponding hand-written file, for
example factory.cc.
TBR: hpayer@chromium.org
Bug: v8:7793
Change-Id: Ie172babad1fc7422fd1059c48f5dafaa53e50c8b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2414218
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70060}
For js frame, we want to display currently executing function.
Change-Id: If33b04279dafdf6e4834bfb6c7240e8e7e799fc7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2411483
Reviewed-by: Seth Brenith <seth.brenith@microsoft.com>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Z Nguyen-Huu <duongn@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#70018}
While the sampler checked if the sampled thread had the Isolate locked
(if locks are being used) under Linux, the check was not done under
Windows (or Fuchsia) which meant that in a multi-threading application
under Windows, thread locking was not checked making it prone to seg
faults and the like as the profiler would be using isolate->js_entry_sp
to determine the stack to walk but isolate->js_entry_sp is the stack
pointer for the thread that currently has the Isolate lock so, if the
sampled thread does not have the lock, the sampler woud be iterating
over the wrong stack, one that might actually be actively changing on
another thread. The fix was to move the lock check into CpuSampler
and Ticker (--prof) so all OSes would do the correct check.
The basic concept is that on all operating systems a CpuProfiler, and
so its corresponding CpuCampler, the profiler is tied to a thread.
This is not based on first principles or anything, it's simply the
way it works in V8, though it is a useful conceit as it makes
visualization and interpretation of profile data much easier.
To collect a sample on a thread associated with a profiler the thread
must be stopped for obvious reasons -- walking the stack of a running
thread is a formula for disaster. The mechanism for stopping a thread
is OS-specific and is done in sample.cc. There are currently three
basic approaches, one for Linux/Unix variants, one for Windows and one
for Fuchsia. The approaches vary as to which thread actually collects
the sample -- under Linux the sample is actually collected on the
(interrupted) sampled thread whereas under Fuchsia/Windows it's on
a separate thread.
However, in a multi-threaded environment (where Locker is used), it's
not sufficient for the sampled thread to be stopped. Because the stack
walk involves looking in the Isolate heap, no other thread can be
messing with the heap while the sample is collected. The only ways to
ensure this would be to either stop all threads whenever collecting a
sample, or to ensure that the thread being sampled holds the Isolate
lock so prevents other threads from messing with the heap. While there
might be something to be said for the "stop all threads" approach, the
current approach in V8 is to only stop the sampled thread so, if in a
multi-threaded environment, the profiler must check if the thread being
sampled holds the Isolate lock.
Since this check must be done, independent of which thread the sample
is being collected on (since it varies from OS to OS), the approach is
to save the thread id of the thread to be profiled/sampled when the
CpuSampler is instantiated (on all OSes it is instantiated on the
sampled thread) and then check that thread id against the Isolate lock
holder thread id before collecting a sample. If it matches, we know
sample.cc has stop the sampled thread, one way or another, and we know
that no other thread can mess with the heap (since the stopped thread
holds the Isolate lock) so it's safe to walk the stack and collect data
from the heap so the sample can be taken. It it doesn't match, we can't
safely collect the sample so we don't.
Bug: v8:10850
Change-Id: Iba6cabcd3e11a19c261c004103e37e806934dc6f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2411343
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69952}
tools/debug_helper:run_mkgrokdump used to only depend on mkgrokdump.
However, the snapshot can change without affecting the mkgrokdump
binary itself. So, if the mkgrokdump binary doesn't change, then
run_mkgrokdump doesn't run, even if the snapshot changed.
This could cause mysterious test failures in incremental builds, in
particular for tests testing the contents of heap-constants-gen.cc.
Now, we make run_mkgrokdump depend on run_mksnapshot_default
directly, so that snapshot updates force an mkgrokdump run.
Change-Id: Ia3871e1b4fa15ec2dbc0bc5463afdb427cb39c61
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2400987
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69776}
Cast resource field in ExternalString as
v8: :String::ExternalStringResourceBase* would give us more info.
Change-Id: Iae97b477f400f58365e2381b7230d2226d490aa7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2388742
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#69734}
This reverts commit dfb3f7daa5.
Reason for revert: Breaks LSAN & ASAN flakily: https://bugs.chromium.org/p/v8/issues/detail?id=10861
Original change's description:
> [cpu-profiler] Ensure sampled thread has Isolate lock under Windows
>
> While the sampler checked if the sampled thread had the Isolate locked
> (if locks are being used) under Linux, the check was not done under
> Windows (or Fuchsia) which meant that in a multi-threading application
> under Windows, thread locking was not checked making it prone to seg
> faults and the like as the profiler would be extracting info from a
> heap in motion. The fix was to move the lock check into CpuSampler
> and Ticker (--prof) so all OSes would do the correct check.
>
> The basic concept is that on all operating systems a CpuProfiler, and
> so its corresponding CpuCampler, the profiler is tied to a thread.
> This is not based on first principles or anything, it's simply the
> way it works in V8, though it is a useful conceit as it makes
> visualization and interpretation of profile data much easier.
>
> To collect a sample on a thread associated with a profiler the thread
> must be stopped for obvious reasons -- walking the stack of a running
> thread is a formula for disaster. The mechanism for stopping a thread
> is OS-specific and is done in sample.cc. There are currently three
> basic approaches, one for Linux/Unix variants, one for Windows and one
> for Fuchsia. The approaches vary as to which thread actually collects
> the sample -- under Linux the sample is actually collected on the
> (interrupted) sampled thread whereas under Fuchsia/Windows it's on
> a separate thread.
>
> However, in a multi-threaded environment (where Locker is used), it's
> not sufficient for the sampled thread to be stopped. Because the stack
> walk involves looking in the Isolate heap, no other thread can be
> messing with the heap while the sample is collected. The only ways to
> ensure this would be to either stop all threads whenever collecting a
> sample, or to ensure that the thread being sampled holds the Isolate
> lock so prevents other threads from messing with the heap. While there
> might be something to be said for the "stop all threads" approach, the
> current approach in V8 is to only stop the sampled thread so, if in a
> multi-threaded environment, the profiler must check if the thread being
> sampled holds the Isolate lock.
>
> Since this check must be done, independent of which thread the sample
> is being collected on (since it varies from OS to OS), the approach is
> to save the thread id of the thread to be profiled/sampled when the
> CpuSampler is instantiated (on all OSes it is instantiated on the
> sampled thread) and then check that thread id against the Isolate lock
> holder thread id before collecting a sample. If it matches, we know
> sample.cc has stop the sampled thread, one way or another, and we know
> that no other thread can mess with the heap (since the stopped thread
> holds the Isolate lock) so it's safe to walk the stack and collect data
> from the heap so the sample can be taken. It it doesn't match, we can't
> safely collect the sample so we don't.
>
> Bug: v8:10850
> Change-Id: Iab2493130b9328430d7e5f5d3cf90ad6d10b1892
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2377108
> Reviewed-by: Peter Marshall <petermarshall@chromium.org>
> Commit-Queue: Peter Marshall <petermarshall@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#69623}
TBR=akodat@rocketsoftware.com,petermarshall@chromium.org,petermarshall@google.com
Change-Id: Ib6b6dc4ce109d5aa4e504fa7c9769f5cd95ddd0c
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:10850
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2387570
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69638}
While the sampler checked if the sampled thread had the Isolate locked
(if locks are being used) under Linux, the check was not done under
Windows (or Fuchsia) which meant that in a multi-threading application
under Windows, thread locking was not checked making it prone to seg
faults and the like as the profiler would be extracting info from a
heap in motion. The fix was to move the lock check into CpuSampler
and Ticker (--prof) so all OSes would do the correct check.
The basic concept is that on all operating systems a CpuProfiler, and
so its corresponding CpuCampler, the profiler is tied to a thread.
This is not based on first principles or anything, it's simply the
way it works in V8, though it is a useful conceit as it makes
visualization and interpretation of profile data much easier.
To collect a sample on a thread associated with a profiler the thread
must be stopped for obvious reasons -- walking the stack of a running
thread is a formula for disaster. The mechanism for stopping a thread
is OS-specific and is done in sample.cc. There are currently three
basic approaches, one for Linux/Unix variants, one for Windows and one
for Fuchsia. The approaches vary as to which thread actually collects
the sample -- under Linux the sample is actually collected on the
(interrupted) sampled thread whereas under Fuchsia/Windows it's on
a separate thread.
However, in a multi-threaded environment (where Locker is used), it's
not sufficient for the sampled thread to be stopped. Because the stack
walk involves looking in the Isolate heap, no other thread can be
messing with the heap while the sample is collected. The only ways to
ensure this would be to either stop all threads whenever collecting a
sample, or to ensure that the thread being sampled holds the Isolate
lock so prevents other threads from messing with the heap. While there
might be something to be said for the "stop all threads" approach, the
current approach in V8 is to only stop the sampled thread so, if in a
multi-threaded environment, the profiler must check if the thread being
sampled holds the Isolate lock.
Since this check must be done, independent of which thread the sample
is being collected on (since it varies from OS to OS), the approach is
to save the thread id of the thread to be profiled/sampled when the
CpuSampler is instantiated (on all OSes it is instantiated on the
sampled thread) and then check that thread id against the Isolate lock
holder thread id before collecting a sample. If it matches, we know
sample.cc has stop the sampled thread, one way or another, and we know
that no other thread can mess with the heap (since the stopped thread
holds the Isolate lock) so it's safe to walk the stack and collect data
from the heap so the sample can be taken. It it doesn't match, we can't
safely collect the sample so we don't.
Bug: v8:10850
Change-Id: Iab2493130b9328430d7e5f5d3cf90ad6d10b1892
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2377108
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69623}
Get value from type payload, check and show bitset name.
Change-Id: I6d0e0f30fca0b2aaddfd5f18abf948886552f2dc
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2258815
Commit-Queue: Z Nguyen-Huu <duongn@microsoft.com>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#68495}
