CodeKind::OPTIMIZED_CODE -> TURBOFAN
Kinds are now more fine-grained and distinguish between TF, TP, NCI.
CodeKind::STUB -> DEOPT_ENTRIES_OR_FOR_TESTING
Code stubs (like builtins, but generated at runtime) were removed from
the codebase years ago, this is the last remnant. This kind is used
only for deopt entries (which should be converted into builtins) and
for tests.
Change-Id: I67beb15377cb60f395e9b051b25f3e5764982e93
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2440335
Auto-Submit: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Mythri Alle <mythria@chromium.org>
Reviewed-by: Mythri Alle <mythria@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70234}
With the new Turbofan variants (NCI and Turboprop), we need a way to
distinguish between them both during and after compilation. We
initially introduced CompilationTarget to track the variant during
compilation, but decided to reuse the code kind as the canonical spot to
store this information instead.
Why? Because it is an established mechanism, already available in most
of the necessary spots (inside the pipeline, on Code objects, in
profiling traces).
This CL removes CompilationTarget and adds a new
NATIVE_CONTEXT_INDEPENDENT kind, plus helper functions to determine
various things about a given code kind (e.g.: does this code kind
deopt?).
As a (very large) drive-by, refactor both Code::Kind and
AbstractCode::Kind into a new CodeKind enum class.
Bug: v8:8888
Change-Id: Ie858b9a53311b0731630be35cf5cd108dee95b39
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2336793
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69244}
Switch all uses of NewCode and TryNewCode to CodeBuilder and remove these
methods.
NewCode and TryNewCode use a large number of default parameters, which makes
it difficult to use and add any new ones. Large chunks of code were also
duplicated across TryNewCode and NewCode. The previous CL
(https://chromium-review.googlesource.com/c/v8/v8/+/1585736) added a new
CodeBuilder class which allows much simpler building of Code objects.
Bug: v8:9183
Change-Id: I9f6884f35a3284cbd40746376f0f27e36f9051b5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1585737
Commit-Queue: Maciej Goszczycki <goszczycki@google.com>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61096}
This basically adjusts reality to match our expectations. Methods based
on Code::kConstantPoolOffset expected the constant pool to be located
immediately following the handler table and before the code comments
section, while it was actually emitted before the jump table. We did
not notice earlier since this is only relevant on ppc.
Bug: v8:8758
Change-Id: I189af491fe133a7dc480ff4056372ba7a27faa81
Reviewed-on: https://chromium-review.googlesource.com/c/1445880
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#59299}
This is a reland of 9c0a48580b
Original change's description:
> Reland "Reland "[code-comments] Put code comments into the code object""
>
> This is a reland of ed3d647284
>
> This reland fixes that padding at the end of Wasm instruction streams
> triggered asserts in the code printer.
>
> Original change's description:
> > Reland "[code-comments] Put code comments into the code object"
> >
> > This is a reland of e774cffe2b
> >
> > This reland disables a test as v8:8548 is blocking it, which was
> > broken by a recent CL. CQ did not catch this because the merge-base
> > CQ used did not yet contain the CL that caused v8:8548.
> >
> > Original change's description:
> > > [code-comments] Put code comments into the code object
> > >
> > > Code comments in the snapshot can now be enabled with gn
> > > arg 'v8_enable_snapshot_code_comments'
> > >
> > > Bug: v8:7989
> > > Change-Id: I8bd00cafa63132d00d849394c311ba15e6b6daf3
> > > Reviewed-on: https://chromium-review.googlesource.com/c/1329173
> > > Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
> > > Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> > > Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> > > Reviewed-by: Michael Stanton <mvstanton@chromium.org>
> > > Cr-Commit-Position: refs/heads/master@{#58020}
> >
> > TBR=mvstanton@chromium.org,mstarzinger@chromium.org,jgruber@chromium.org,tebbi@chromium.org
> >
> > Bug: v8:7989, v8:8548
> > Change-Id: I464fc897205fefdf2dfc2eadc54d699c4e08a0e9
> > Reviewed-on: https://chromium-review.googlesource.com/c/1361166
> > Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
> > Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#58028}
>
> Bug: v8:7989, v8:8548
> Change-Id: I254f55ff687ad049f8d92b09331ed26a2bd05d7d
> Reviewed-on: https://chromium-review.googlesource.com/c/1371784
> Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#58221}
TBR=jgruber@chromium.org,mstarzinger@chromium.org
Bug: v8:7989, v8:8548, v8:8593
Change-Id: I4f7ffc98e0281c7b744eb4a04ba0763896c7b59b
Reviewed-on: https://chromium-review.googlesource.com/c/1375919
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58232}
This reverts commit 9c0a48580b.
Reason for revert: Seems to break nosnap debug: https://ci.chromium.org/p/v8/builders/luci.v8.ci/V8%20Linux%20-%20nosnap%20-%20debug/22228
Original change's description:
> Reland "Reland "[code-comments] Put code comments into the code object""
>
> This is a reland of ed3d647284
>
> This reland fixes that padding at the end of Wasm instruction streams
> triggered asserts in the code printer.
>
> Original change's description:
> > Reland "[code-comments] Put code comments into the code object"
> >
> > This is a reland of e774cffe2b
> >
> > This reland disables a test as v8:8548 is blocking it, which was
> > broken by a recent CL. CQ did not catch this because the merge-base
> > CQ used did not yet contain the CL that caused v8:8548.
> >
> > Original change's description:
> > > [code-comments] Put code comments into the code object
> > >
> > > Code comments in the snapshot can now be enabled with gn
> > > arg 'v8_enable_snapshot_code_comments'
> > >
> > > Bug: v8:7989
> > > Change-Id: I8bd00cafa63132d00d849394c311ba15e6b6daf3
> > > Reviewed-on: https://chromium-review.googlesource.com/c/1329173
> > > Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
> > > Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> > > Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> > > Reviewed-by: Michael Stanton <mvstanton@chromium.org>
> > > Cr-Commit-Position: refs/heads/master@{#58020}
> >
> > TBR=mvstanton@chromium.org,mstarzinger@chromium.org,jgruber@chromium.org,tebbi@chromium.org
> >
> > Bug: v8:7989, v8:8548
> > Change-Id: I464fc897205fefdf2dfc2eadc54d699c4e08a0e9
> > Reviewed-on: https://chromium-review.googlesource.com/c/1361166
> > Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
> > Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#58028}
>
> Bug: v8:7989, v8:8548
> Change-Id: I254f55ff687ad049f8d92b09331ed26a2bd05d7d
> Reviewed-on: https://chromium-review.googlesource.com/c/1371784
> Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#58221}
TBR=mvstanton@chromium.org,mstarzinger@chromium.org,sigurds@chromium.org,jgruber@chromium.org
Change-Id: I681a3c63120c6ab953bfe9cd2b07bcf560ebfdee
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:7989, v8:8548
Reviewed-on: https://chromium-review.googlesource.com/c/1375916
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58228}
This is a reland of ed3d647284
This reland fixes that padding at the end of Wasm instruction streams
triggered asserts in the code printer.
Original change's description:
> Reland "[code-comments] Put code comments into the code object"
>
> This is a reland of e774cffe2b
>
> This reland disables a test as v8:8548 is blocking it, which was
> broken by a recent CL. CQ did not catch this because the merge-base
> CQ used did not yet contain the CL that caused v8:8548.
>
> Original change's description:
> > [code-comments] Put code comments into the code object
> >
> > Code comments in the snapshot can now be enabled with gn
> > arg 'v8_enable_snapshot_code_comments'
> >
> > Bug: v8:7989
> > Change-Id: I8bd00cafa63132d00d849394c311ba15e6b6daf3
> > Reviewed-on: https://chromium-review.googlesource.com/c/1329173
> > Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
> > Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> > Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> > Reviewed-by: Michael Stanton <mvstanton@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#58020}
>
> TBR=mvstanton@chromium.org,mstarzinger@chromium.org,jgruber@chromium.org,tebbi@chromium.org
>
> Bug: v8:7989, v8:8548
> Change-Id: I464fc897205fefdf2dfc2eadc54d699c4e08a0e9
> Reviewed-on: https://chromium-review.googlesource.com/c/1361166
> Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
> Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#58028}
Bug: v8:7989, v8:8548
Change-Id: I254f55ff687ad049f8d92b09331ed26a2bd05d7d
Reviewed-on: https://chromium-review.googlesource.com/c/1371784
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58221}
This reverts commit ed3d647284.
Reason for revert:
https://ci.chromium.org/p/v8/builders/luci.v8.ci/V8%20Linux%20-%20noi18n%20-%20debug/24178
Original change's description:
> Reland "[code-comments] Put code comments into the code object"
>
> This is a reland of e774cffe2b
>
> This reland disables a test as v8:8548 is blocking it, which was
> broken by a recent CL. CQ did not catch this because the merge-base
> CQ used did not yet contain the CL that caused v8:8548.
>
> Original change's description:
> > [code-comments] Put code comments into the code object
> >
> > Code comments in the snapshot can now be enabled with gn
> > arg 'v8_enable_snapshot_code_comments'
> >
> > Bug: v8:7989
> > Change-Id: I8bd00cafa63132d00d849394c311ba15e6b6daf3
> > Reviewed-on: https://chromium-review.googlesource.com/c/1329173
> > Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
> > Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> > Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> > Reviewed-by: Michael Stanton <mvstanton@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#58020}
>
> TBR=mvstanton@chromium.org,mstarzinger@chromium.org,jgruber@chromium.org,tebbi@chromium.org
>
> Bug: v8:7989, v8:8548
> Change-Id: I464fc897205fefdf2dfc2eadc54d699c4e08a0e9
> Reviewed-on: https://chromium-review.googlesource.com/c/1361166
> Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
> Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#58028}
TBR=mvstanton@chromium.org,mstarzinger@chromium.org,sigurds@chromium.org,jgruber@chromium.org
Change-Id: I1075bb09de7cb8dad71e31ff51a4e7bb6a200a8b
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:7989, v8:8548
Reviewed-on: https://chromium-review.googlesource.com/c/1362043
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58029}
This is a reland of e774cffe2b
This reland disables a test as v8:8548 is blocking it, which was
broken by a recent CL. CQ did not catch this because the merge-base
CQ used did not yet contain the CL that caused v8:8548.
Original change's description:
> [code-comments] Put code comments into the code object
>
> Code comments in the snapshot can now be enabled with gn
> arg 'v8_enable_snapshot_code_comments'
>
> Bug: v8:7989
> Change-Id: I8bd00cafa63132d00d849394c311ba15e6b6daf3
> Reviewed-on: https://chromium-review.googlesource.com/c/1329173
> Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Reviewed-by: Michael Stanton <mvstanton@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#58020}
TBR=mvstanton@chromium.org,mstarzinger@chromium.org,jgruber@chromium.org,tebbi@chromium.org
Bug: v8:7989, v8:8548
Change-Id: I464fc897205fefdf2dfc2eadc54d699c4e08a0e9
Reviewed-on: https://chromium-review.googlesource.com/c/1361166
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58028}
Code comments in the snapshot can now be enabled with gn
arg 'v8_enable_snapshot_code_comments'
Bug: v8:7989
Change-Id: I8bd00cafa63132d00d849394c311ba15e6b6daf3
Reviewed-on: https://chromium-review.googlesource.com/c/1329173
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58020}
The "Address" type is V8's general-purpose type for manipulating memory
addresses. Per the C++ spec, pointer arithmetic and pointer comparisons
are undefined behavior except within the same array; since we generally
don't operate within a C++ array, our general-purpose type shouldn't be
a pointer type.
Bug: v8:3770
Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng;master.tryserver.blink:linux_trusty_blink_rel
Change-Id: Ib96016c24a0f18bcdba916dabd83e3f24a1b5779
Reviewed-on: https://chromium-review.googlesource.com/988657
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52601}
There is no good reason to have the meat of most objects' initialization
logic in heap.cc, all wrapped by the CALL_HEAP_FUNCTION macro. Instead,
this CL changes the protocol between Heap and Factory to be AllocateRaw,
and all object initialization work after (possibly retried) successful
raw allocation happens in the Factory.
This saves about 20KB of binary size on x64.
Original review: https://chromium-review.googlesource.com/c/v8/v8/+/959533
Originally landed as r52416 / f9a2e24bbc
Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
Change-Id: Id072cbe6b3ed30afd339c7e502844b99ca12a647
Reviewed-on: https://chromium-review.googlesource.com/1000540
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52492}
This reverts commit f9a2e24bbc.
Reason for revert: gc stress failures not all fixed by follow up.
Original change's description:
> [cleanup] Refactor the Factory
>
> There is no good reason to have the meat of most objects' initialization
> logic in heap.cc, all wrapped by the CALL_HEAP_FUNCTION macro. Instead,
> this CL changes the protocol between Heap and Factory to be AllocateRaw,
> and all object initialization work after (possibly retried) successful
> raw allocation happens in the Factory.
>
> This saves about 20KB of binary size on x64.
>
> Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
> Change-Id: Icbfdc4266d7be8b48d2fe085f03411743dc6a0ca
> Reviewed-on: https://chromium-review.googlesource.com/959533
> Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
> Reviewed-by: Hannes Payer <hpayer@chromium.org>
> Reviewed-by: Yang Guo <yangguo@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#52416}
TBR=jkummerow@chromium.org,yangguo@chromium.org,mstarzinger@chromium.org,hpayer@chromium.org
Change-Id: Idbbc53478742f3e9525eee83342afc6aedae122f
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
Reviewed-on: https://chromium-review.googlesource.com/999414
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52420}
There is no good reason to have the meat of most objects' initialization
logic in heap.cc, all wrapped by the CALL_HEAP_FUNCTION macro. Instead,
this CL changes the protocol between Heap and Factory to be AllocateRaw,
and all object initialization work after (possibly retried) successful
raw allocation happens in the Factory.
This saves about 20KB of binary size on x64.
Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
Change-Id: Icbfdc4266d7be8b48d2fe085f03411743dc6a0ca
Reviewed-on: https://chromium-review.googlesource.com/959533
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52416}
In order to clarify the difference between, e.g., InstructionStart and
instruction_start, rename as follows:
Code::instruction_start -> raw_instruction_start
Code::instruction_end -> raw_instruction_end
Code::instruction_size -> raw_instruction_size
The difference between the camel-case and raw_* function families is
in how they handle off-heap-trampoline Code objects. For example, when
called on an off-heap-trampoline: raw_instruction_start returns the
trampoline's entry point, while InstructionStart returns the off-heap
code's entry point (located in the .text section of the binary).
Some callsites were updated to call the camel-case function family as
appropriate.
Bug: v8:6666
Change-Id: I4a572f47c2d161a853599d7c17879e263b0d1a87
Reviewed-on: https://chromium-review.googlesource.com/997532
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52387}
This patch normalizes the casing of hexadecimal digits in escape
sequences of the form `\xNN` and integer literals of the form
`0xNNNN`.
Previously, the V8 code base used an inconsistent mixture of uppercase
and lowercase.
Google’s C++ style guide uses uppercase in its examples:
https://google.github.io/styleguide/cppguide.html#Non-ASCII_Characters
Moreover, uppercase letters more clearly stand out from the lowercase
`x` (or `u`) characters at the start, as well as lowercase letters
elsewhere in strings.
BUG=v8:7109
TBR=marja@chromium.org,titzer@chromium.org,mtrofin@chromium.org,mstarzinger@chromium.org,rossberg@chromium.org,yangguo@chromium.org,mlippautz@chromium.org
NOPRESUBMIT=true
Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_chromium_rel_ng
Change-Id: I790e21c25d96ad5d95c8229724eb45d2aa9e22d6
Reviewed-on: https://chromium-review.googlesource.com/804294
Commit-Queue: Mathias Bynens <mathias@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49810}
* Avoid "using namespace" statements, which trigger clang's -Wheader-hygiene
warnings in jumbo builds.
* Undefine created macros at the end of source files.
BUG=chromium:746958
Change-Id: I5d25432c314437f607b0e1be22765a6764267ba6
Reviewed-on: https://chromium-review.googlesource.com/610962
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Mostyn Bramley-Moore <mostynb@opera.com>
Cr-Commit-Position: refs/heads/master@{#47347}
... 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}
Cleanup CHECK_EQ order and simplify CHECK_EQ(true/false).
Cleanup callorder for negative numbers
Cleanup callorder order for capital letter constants.
Cleanup callorder for test.x checks.
BUG=
Review-Url: https://codereview.chromium.org/2677183002
Cr-Commit-Position: refs/heads/master@{#42997}
Rebuilding (after touching certain files) is crazy slow because
includes are out of control. Many of these files we need to rebuild are
cctests which pull in more includes than they need.
BUG=v8:5294
Review-Url: https://codereview.chromium.org/2304553002
Cr-Commit-Position: refs/heads/master@{#39080}
the .eh_frame format as part of the jitdump generated when
FLAG_perf_prof is enabled. The final goal is allowing precise unwinding
of callchains that include JITted code when profiling V8 using perf.
Unwinding information is stored in the body of code objects after the
code itself, prefixed with its length and aligned to a 8-byte boundary.
A boolean flag in the header signals its presence, resulting in zero
memory overhead when the generation of unwinding info is disabled or
no such information was attached to the code object.
A new jitdump record type (with id 4) is introduced for specifying
optional unwinding information for code load records. The EhFrameHdr
struct is also introduced, together with a constructor to initialise it
from the associated code object.
At this stage no unwinding information is written to the jitdump, but
the infrastructure for doing so is ready in place.
BUG=v8:4899
LOG=N
Review-Url: https://codereview.chromium.org/1993653003
Cr-Commit-Position: refs/heads/master@{#37296}
