Commit Graph

37 Commits

Author SHA1 Message Date
Leszek Swirski
3c49308ac6 [DEPS] Add abseil to deps
Add a dependency on the chromium abseil-cpp subdir mirror.

Bug: v8:11006
Change-Id: Icaad757269d27c65bc368ed539f84c5bb79ee62d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2464940
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Victor Gomes <victorgomes@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70786}
2020-10-27 09:34:52 +00:00
Samuel Groß
977b77a332 [sandbox][x64] Add a type tag to external pointers
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}
2020-10-09 15:39:44 +00:00
Leszek Swirski
9e26f70529 [ptr-cmpr] Change const Isolate* to IsolateRoot
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}
2020-10-07 08:03:50 +00:00
Tobias Tebbi
21b585165f Reland "[torque] refactor: use -tq only in filenames derived from .tq files"
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.org jgruber@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}
2020-09-25 15:04:18 +00:00
Francis McCabe
92aaace1a9 Revert "[torque] refactor: use -tq only in filenames derived from .tq files"
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}
2020-09-22 17:20:30 +00:00
Tobias Tebbi
64caf2b0b2 [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}
2020-09-22 15:52:58 +00:00
Seth Brenith
42db3676ff Add myself as an owner for debug-helper and v8windbg
Change-Id: I65ed798968b602891e7f8d13c08c9065ab58d6d7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2418367
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#70031}
2020-09-21 15:19:27 +00:00
Z Nguyen-Huu
1cb7aeb988 [v8windbg] Display js function only for js frame
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}
2020-09-21 07:50:14 +00:00
Alex Kodat
76217f5708 [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 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}
2020-09-16 16:17:39 +00:00
Leszek Swirski
0ed32e646d [build] Make run_mkgrokdump explicitly dep on run_mksnapshot
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}
2020-09-09 13:46:32 +00:00
Z Nguyen-Huu
7b8cce7724 [v8windbg] Cast resource as ExternalStringResourceBase*
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}
2020-09-08 12:08:15 +00:00
Peter Marshall
3243506267 Revert "[cpu-profiler] Ensure sampled thread has Isolate lock under Windows"
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}
2020-09-01 10:21:41 +00:00
Alex Kodat
dfb3f7daa5 [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}
2020-08-31 15:18:05 +00:00
Z Nguyen-Huu
40657debf4 [v8windbg] Show bitset name of compiler type
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}
2020-06-23 19:36:36 +00:00
Omer Katz
fff219bff7 heap,cppgc: Update StackState enum values
This CL adds 2 new values to the EmbedderStackState enum with more
explicit names. The old values are updated as aliases to the new
values and marked as soon to be deprecated. This CL also moves the
enum to v8-platform.h so that it can be reused by cppgc.

Depracating individual values in an enum is supported by GCC only
since version 6. Thus new macros were needed for the deprecation
(which delegate to the existing macros when supported). GCC versions
older than 6 are still used by the CQ bots.

Bug: chromium:1056170
Change-Id: Id1ea73edfbbae282b0d8a3bb103dbbbf8ebd417e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2188971
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67744}
2020-05-12 12:07:27 +00:00
Leszek Swirski
4d1f17e4d6 [sandbox] Access ExternalString ResourceData via bottlenecks
Bug: v8:10391
Change-Id: I4e86394c53d02eab797c2daad2ccfde6acb83bf0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2151350
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67619}
2020-05-06 16:34:07 +00:00
Sami Kyostila
9dbab9bbdb [tracing] Migrate tracing to Perfetto track events
This patch replaces V8's tracing implementation (i.e., the TRACE_EVENT
macros) with the track event base implementation from Perfetto. The
advantages of doing this are:

1) This allows us to remove most tracing-related backend code from V8.

2) V8 can start writing strongly typed trace event arguments, which
   are more compact, easier to process and more extensible than legacy
   JSON-based trace arguments.

For the time being, we still support the old trace macros when V8 is
embedded into Chrome and other embedders.

Design doc: https://docs.google.com/document/d/1f7tt4cb-JcA5bQFR1oXk60ncJPpkL02_Hi_Bc6MfTQk/edit#heading=h.398p6b4eaen2

Bug: chromium:1006766
Change-Id: Ie71474fbe065821772b13d851487ebbca680c4ae
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1947688
Commit-Queue: Sami Kyöstilä <skyostil@chromium.org>
Auto-Submit: Sami Kyöstilä <skyostil@chromium.org>
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67217}
2020-04-17 21:31:24 +00:00
Seth Brenith
8b1a5681de [tools] Fix v8windbg behavior on Map's bit_field2
Bill kindly pointed out to me that v8windbg was not handling bit_field2
correctly. The issue was that the constexpr type for ElementsKind was,
somewhat unsurprisingly, "ElementsKind", but v8windbg expected a fully-
qualified type name like "v8::internal::ElementsKind". This change
addresses the problem in two ways:
1. Update v8windbg's type resolution logic to resolve type names as if
   they were used in the v8::internal namespace. This makes it more
   consistent with how those type names are used in other generated
   Torque code, reducing surprises and the number of times we have to
   write `v8::internal::` in .tq files.
2. Add compile-time verification that any constexpr type name used as a
   string in class-debug-readers-tq.cc can also resolve as a type name.

Bug: v8:9376
Change-Id: I349cd6ab586fd8345a1fa8bfc3989bb8e6376ab8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2063769
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#66633}
2020-03-09 17:36:27 +00:00
Tobias Tebbi
4f4d73f225 [torque] Generate GC object visitors for Torque classes
In the process:

* Augment C++-generated Torque classes with SizeFor methods to
  calculate size of instances.

* Add a new "@generateBodyDescriptor" annotation that causes Torque to
  generate C++ BodyDescriptors code that can be used to visit objects
  compatible with existing V8 mechanisms, e.g. GC

* Fully automate C++ macro machinery so that adding non-extern Torque
  class doesn't require any C++ changes, including ensuring generation
  of instance types and proper boilerplate for validators and
  printers.

* Make handling of @export a true annotation, allowing the modifier to
  be used on class declarations.

* Add functionality such that classes with the @export annotation are
  available to be used from C++. Field accessors for exported classes
  are public and factory methods are generated to create instances of
  the objects from C++.

* Change the Torque compiler such that Non-exported classes implicitly
  have the @generateBodyDescriptor annotation added and causes both
  verifiers and printers to be generated.

* Switch non-extern Torque classes from using existing Struct-based
  machinery to being first-class classes that support more existing
  Torque class features.

Change-Id: Ic60e60c2c6bd7acd57f949bce086898ad14a3b03
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2007490
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66621}
2020-03-09 11:37:37 +00:00
Seth Brenith
5f5bcace28 [tools] include missing dep for v8_debug_helper
This fixes a build break in certain configurations. v8_debug_helper
depends on generate_bytecode_builtins_list via the following headers:

In file included from gen/v8/tools/debug_helper/heap-constants-gen.cc:5:
In file included from ../../v8\src/common/ptr-compr-inl.h:10:
In file included from ../../v8\src/execution/isolate.h:19:
In file included from ../../v8\src/builtins/builtins.h:9:

Change-Id: I38e5d851afc6ce52716d3e5e64ae9219df396bd4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2078768
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Auto-Submit: Seth Brenith <seth.brenith@microsoft.com>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66517}
2020-03-02 10:22:15 +00:00
Seth Brenith
534482b35b [tools] Show contents of cached external strings from crash dumps
This change adds support for the postmortem inspection library to show
the content of cached external strings if that content is available. It
also fixes a minor annoyance where strings with unavailable data would
show up as "...". Now, if fetching the very first character fails, we
omit the literal value from the output.

Bug: v8:9376
Change-Id: Id694a774c231ab3467fb59b1c149284729acfb20
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1987922
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#65961}
2020-01-23 21:33:20 +00:00
Seth Brenith
ae8eb6c290 [torque] Generate postmortem data about bitfields
This change updates GetObjectProperties to list all of the bitfields
within a class field, if that class field's type is a bitfield struct.
The representation of bitfields in the GetObjectProperties response is
very similar to the representation of struct fields, but with two extra
bytes of data specifying the shift and size of the bitfield.

Bug: v8:9376
Change-Id: I40a22169f3d01652a7f2db8cface43c2a1e30cfe
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1960835
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#65610}
2020-01-07 16:53:36 +00:00
Seth Brenith
dcb828b46f [tools] Add in-object properties to debug_helper
Until now, the in-object properties on JSObject have been invisible to
tools using the postmortem debugging library. With this change, those
tools will get enough information to show a flat list of property
values. This is still less powerful than the runtime printers, which can
show the corresponding key for each value, but it's a big step up from
manually inspecting memory.

This change basically requires a reimplementation of
Map::GetInObjectProperties for postmortem debugging. I'm not
enthusiastic about duplicating this logic, but it's pretty small and I
don't see any good alternatives.

As a drive-by cleanup, I moved some inline string literals into a batch
of constexpr char arrays.

Bug: v8:9376
Change-Id: Ia24c05f6e823086babaa07882d0d320ab9a225db
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1930174
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#65183}
2019-11-26 16:56:26 +00:00
Seth Brenith
6b11b700d7 [torque][tools] Define layout of DescriptorArray for postmortem tools
This change defines a way that v8_debug_helper can describe object
fields which are packed structs, and uses it for the "descriptors" field
in DescriptorArray.

In more detail:
- debug-helper.h (the public interface for v8_debug_helper) adds a size
  and an optional list of struct properties to ObjectProperty.
- debug-helper-internal.h mirrors those changes to the internal class
  hierarchy which maintains proper unique_ptr ownership.
- In src/torque/class-debug-reader-generator.cc,
  - Some existing logic is moved into smaller functions.
  - New logic is added to generate the field list for structs. Example
    output is included in a comment above the function
    GenerateGetPropsChunkForField.

Bug: v8:9376
Change-Id: I531acac039ccb42050641448a4cbaec26186a7bc
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1894362
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65079}
2019-11-20 16:56:39 +00:00
Seth Brenith
91e6421ccb [torque] Use generated instance types, part 1
This change begins making use of the fact that Torque now knows about
the relationship between classes and instance types, to replace a few
repetitive lists:

- Instance type checkers (single and range), defined in
  src/objects/instance-type.h
- Verification dispatch in src/diagnostics/objects-debug.cc
- Printer dispatch in src/diagnostics/objects-printer.cc
- Postmortem object type detection in
  tools/debug_helper/get-object-properties.cc

Torque is updated to generate four macro lists for the instance types,
representing all of the classes separated in two dimensions: classes
that correspond to a single instance type versus those that have a
range, and classes that are fully defined in Torque (with fields and
methods inside '{}') versus those that are only declared. The latter
distinction is useful because fully-defined classes are guaranteed to
correspond to real C++ classes, whereas only-declared classes are not.

A few other changes were required to make the lists above work:

- Renamed IsFiller to IsFreeSpaceOrFiller to better reflect what it does
  and avoid conflicts with the new macro-generated IsFiller method. This
  is the part I'm most worried about: I think the new name is an
  improvement for clarity and consistency, but I could imagine someone
  typing IsFiller out of habit and introducing a bug. If we'd prefer to
  keep the name IsFiller, my other idea is to rename FreeSpace to
  VariableSizeFiller and Filler to FixedSizeFiller.
- Made Tuple3 extend from Struct, not Tuple2, because IsTuple2 is
  expected to check for only TUPLE2_TYPE and not include TUPLE3_TYPE.
- Normalized the dispatched behavior for BigIntBase and HeapNumber.
- Added a few new object printers.

Bug: v8:7793
Change-Id: I5462bb105f8a314baa59bd6ab6ab6215df6f313c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1860314
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Dan Elphick <delphick@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64597}
2019-10-28 18:30:31 +00:00
Seth Brenith
4d0360aa84 [tools] Add list of classes to v8_debug_helper
This change extends v8_debug_helper to export a new method that returns
a list of all known heap object types.

Why? We can substantially improve the user experience in our work-in-
progress WinDbg extension if we register handlers not only for
v8::internal::Object but for every specific HeapObject type. This has
two benefits:

- You save a click: if you're expanding a local variable of a more
  specific type than Object, you can see properties immediately rather
  than first needing to expand a sub-item that casts the variable to
  Object.
- You retain the type hint: GetObjectProperties accepts a type hint
  string, and it's super important to pass it when working in a crash
  dump because the object's Map is probably inaccessible. If we have to
  cast to Object first, we lose this data.

Bug: v8:9376
Change-Id: I4d635a1826574a3d08ac657e848e1fe7b83849fe
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1822859
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#64331}
2019-10-16 15:35:18 +00:00
Seth Brenith
386ed8a9a0 Update postmortem tools to use unsigned compressed pointers
The tests were already passing because they happened to use objects
allocated in the lower half of the heap reservation, but this small
change should make behavior more consistent.

Change-Id: Ib6be3123d347234f4771c213f2209bfe6e19c569
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1860332
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#64294}
2019-10-15 14:39:10 +00:00
Seth Brenith
61815a22bd Use consistent capitalization rules for instance types
In preparation for allowing Torque to generate the list of instance
types, I'd like to make the rules a bit more consistent for how instance
types are spelled. This CL is my proposal for a system where every
non-String instance type name is exactly equal to calling
CapifyStringWithUnderscores on the corresponding class name and
appending "_TYPE".

This change is almost all find&replace; the only manual changes are in:
- src/objects/instance-type.h
- src/torque/utils.cc
- tools/gen-postmortem-metadata.py

This change is in response to the review comment
https://chromium-review.googlesource.com/c/v8/v8/+/1757094/25/src/builtins/base.tq#132

Change-Id: Ife3857292669f54931708e934398b2684e60bea5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1814888
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Frank Tang <ftang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64199}
2019-10-09 17:44:42 +00:00
Seth Brenith
1d3c4975be [tools] Use instance types of known Maps in v8_debug_helper
If we can read an object's Map pointer but not any data from the Map
itself, we may still be able to accurately describe the object's type if
the Map pointer matches one of the known Maps from the snapshot.
GetObjectProperties uses that data in one of two ways:
- If it is sure that the Map pointer matches a known Map, then it uses
  the type from that Map and continues as if it read the type normally.
- If the Map pointer is at the right offset within a heap page to match
  a known Map, but the caller didn't provide the addresses of the first
  pages in Map space or read-only space, then the type of that Map is
  just a guess and gets returned in a separate array. This gives the
  caller the opportunity to present guessed types to the user, and
  perhaps call again using the guessed type as the type hint.

Bug: v8:9376
Change-Id: I187f67b77e76699863a14534a9d635b79f654124
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1787986
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63908}
2019-09-20 16:00:59 +00:00
Clemens Hammacher
75790c9823 [iwyu] Add missing includes of <memory> for std::unique_ptr
After https://crrev.com/c/1800575 and https://crrev.com/c/1803343,
which tried to fix this on occuring compile errors, this CL
systematically adds the <memory> include to each header that uses
{std::unique_ptr}.

R=sigurds@chromium.org
TBR=mlippautz@chromium.org,alph@chromium.org,rmcilroy@chromium.org,verwaest@chromium.org

Bug: v8:9396
Change-Id: If7f9c3140842f9543135dddd7344c0f357999da0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1803349
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63767}
2019-09-13 17:13:36 +00:00
Clemens Hammacher
859b2d77c6 Replace base::make_unique by std::make_unique
Since we switched to C++14 now, we can use {std::make_unique} instead
of our own {base::make_unique} from {template-utils.h}.

R=mstarzinger@chromium.org, yangguo@chromium.org

Bug: v8:9687
No-Try: true
Change-Id: I660eb30038bbb079cee93c7861cd87ccd134f01b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1789300
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63642}
2019-09-10 11:21:51 +00:00
Seth Brenith
0a31d508f1 [tools] Teach v8_debug_helper where heap spaces start in ptr-compr mode
v8_debug_helper attempts to flag known object pointers when it can
recognize them, even if the memory pointed to is not available in the
crash dump. In ptr-compr builds, the first pages of the map space,
read-only space, and old space are always at the same offsets within the
heap reservation region, so we can more easily detect known objects.

Bug: v8:9376
Change-Id: I04e0d2357143d753f575f556e94f8fd42ce9d811
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1783729
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63624}
2019-09-09 16:14:12 +00:00
Seth Brenith
2ccca6c5ac [tools][torque] Include string values in GetObjectProperties responses
This change provides a quick way to see string contents in postmortem
debugging sessions, without digging through a (possibly very large, in
the case of ConsString) tree of properties. As well as being convenient
for inspecting String objects, this functionality will also be necessary
for displaying property names on JSReceiver objects. In order to support
custom behaviors for specific classes, this change extends the existing
generated debug reader classes with a visitor pattern.

Bug: v8:9376
Change-Id: I70eab9ea4e74ca0fab39bf5998d6a602716a4202
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1771939
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#63485}
2019-08-30 21:56:06 +00:00
Seth Brenith
1a815e44b5 [tools][torque]Improve postmortem API behavior on strings
This change adds the indexed field for the characters in the definition
of sequential string types, and introduces support for recognizing the
various specific string types in v8_debug_helper. In an attempt to
avoid duplicating info about string instance types, it also refactors
String::Get so that StringShape (a simple class usable by postmortem
tools) can dispatch using a class that defines behaviors for each
concrete type.

Bug: v8:9376
Change-Id: Id0653040f6decddc004c73f8fe93d2187828c2c6
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1735795
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63352}
2019-08-22 18:40:05 +00:00
Seth Brenith
0921e8f28b Reland "Add postmortem debugging helper library"
This is a reland of 517ab73fd7

Updates since original: now compressed pointers passed to the function
GetObjectProperties are required to be sign-extended. Previously, the
function allowed zero-extended values, but that led to ambiguity on
pointers like 0x88044919: is it compressed or is the heap range actually
centered on 0x100000000?

Original change's description:
> Add postmortem debugging helper library
>
> This change begins to implement the functionality described in
> https://docs.google.com/document/d/1evHnb1uLlSbvHAAsmOXyc25x3uh1DjgNa8u1RHvwVhk/edit#
> for investigating V8 state in crash dumps.
>
> This change adds a new library, v8_debug_helper, for providing platform-
> agnostic assistance with postmortem debugging. This library can be used
> by extensions built for debuggers such as WinDbg or lldb. Its public API
> is described by debug-helper.h; currently the only method it exposes is
> GetObjectProperties, but we'd like to add more functionality over time.
> The API surface is restricted to plain C-style structs and pointers, so
> that it's easy to link from a debugger extension built with a different
> toolchain.
>
> This change also adds a new cctest file to exercise some basic
> interaction with the new library.
>
> The API function GetObjectProperties takes an object pointer (which
> could be compressed, or weak, or a SMI), and returns a string
> description of the object and a list of properties the object contains.
> For now, the list of properties is entirely based on Torque object
> definitions, but we expect to add custom properties in future updates so
> that it can be easier to make sense of complex data structures such as
> dictionaries.
>
> GetObjectProperties does several things that are intended to generate
> somewhat useful results even in cases where memory may be corrupt or
> unavailable:
> - The caller may optionally provide a type string which will be used if
>   the memory for the object's Map is inaccessible.
> - All object pointers are compared against the list of known objects
>   generated by mkgrokdump. The caller may optionally provide the
>   pointers for the first pages of various heap spaces, to avoid spurious
>   matches. If those pointers are not provided, then any matches are
>   prefixed with "maybe" in the resulting description string, such as
>   "maybe UndefinedValue (0x4288000341 <Oddball>)".
>
> Bug: v8:9376
>
> Change-Id: Iebf3cc2dea3133c7811bcefcdf38d9458b02fded
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1628012
> Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
> Reviewed-by: Yang Guo <yangguo@chromium.org>
> Reviewed-by: Michael Stanton <mvstanton@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#62882}

Bug: v8:9376
Change-Id: I866a1cc9d4c34bfe10c7b98462451fe69763cf3f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1717090
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#63008}
2019-07-31 14:30:19 +00:00
Zhi An Ng
6747e3a186 Revert "Add postmortem debugging helper library"
This reverts commit 517ab73fd7.

Reason for revert: Test failures https://bugs.chromium.org/p/v8/issues/detail?id=9538

Original change's description:
> Add postmortem debugging helper library
> 
> This change begins to implement the functionality described in
> https://docs.google.com/document/d/1evHnb1uLlSbvHAAsmOXyc25x3uh1DjgNa8u1RHvwVhk/edit#
> for investigating V8 state in crash dumps.
> 
> This change adds a new library, v8_debug_helper, for providing platform-
> agnostic assistance with postmortem debugging. This library can be used
> by extensions built for debuggers such as WinDbg or lldb. Its public API
> is described by debug-helper.h; currently the only method it exposes is
> GetObjectProperties, but we'd like to add more functionality over time.
> The API surface is restricted to plain C-style structs and pointers, so
> that it's easy to link from a debugger extension built with a different
> toolchain.
> 
> This change also adds a new cctest file to exercise some basic
> interaction with the new library.
> 
> The API function GetObjectProperties takes an object pointer (which
> could be compressed, or weak, or a SMI), and returns a string
> description of the object and a list of properties the object contains.
> For now, the list of properties is entirely based on Torque object
> definitions, but we expect to add custom properties in future updates so
> that it can be easier to make sense of complex data structures such as
> dictionaries.
> 
> GetObjectProperties does several things that are intended to generate
> somewhat useful results even in cases where memory may be corrupt or
> unavailable:
> - The caller may optionally provide a type string which will be used if
>   the memory for the object's Map is inaccessible.
> - All object pointers are compared against the list of known objects
>   generated by mkgrokdump. The caller may optionally provide the
>   pointers for the first pages of various heap spaces, to avoid spurious
>   matches. If those pointers are not provided, then any matches are
>   prefixed with "maybe" in the resulting description string, such as
>   "maybe UndefinedValue (0x4288000341 <Oddball>)".
> 
> Bug: v8:9376
> 
> Change-Id: Iebf3cc2dea3133c7811bcefcdf38d9458b02fded
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1628012
> Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
> Reviewed-by: Yang Guo <yangguo@chromium.org>
> Reviewed-by: Michael Stanton <mvstanton@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#62882}

TBR=yangguo@chromium.org,mvstanton@chromium.org,jgruber@chromium.org,tebbi@chromium.org,seth.brenith@microsoft.com

Change-Id: Ia078f2e8d101d2375b5db88021b2d65d28f1b075
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:9376
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1716033
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62899}
2019-07-24 16:31:54 +00:00
Seth Brenith
517ab73fd7 Add postmortem debugging helper library
This change begins to implement the functionality described in
https://docs.google.com/document/d/1evHnb1uLlSbvHAAsmOXyc25x3uh1DjgNa8u1RHvwVhk/edit#
for investigating V8 state in crash dumps.

This change adds a new library, v8_debug_helper, for providing platform-
agnostic assistance with postmortem debugging. This library can be used
by extensions built for debuggers such as WinDbg or lldb. Its public API
is described by debug-helper.h; currently the only method it exposes is
GetObjectProperties, but we'd like to add more functionality over time.
The API surface is restricted to plain C-style structs and pointers, so
that it's easy to link from a debugger extension built with a different
toolchain.

This change also adds a new cctest file to exercise some basic
interaction with the new library.

The API function GetObjectProperties takes an object pointer (which
could be compressed, or weak, or a SMI), and returns a string
description of the object and a list of properties the object contains.
For now, the list of properties is entirely based on Torque object
definitions, but we expect to add custom properties in future updates so
that it can be easier to make sense of complex data structures such as
dictionaries.

GetObjectProperties does several things that are intended to generate
somewhat useful results even in cases where memory may be corrupt or
unavailable:
- The caller may optionally provide a type string which will be used if
  the memory for the object's Map is inaccessible.
- All object pointers are compared against the list of known objects
  generated by mkgrokdump. The caller may optionally provide the
  pointers for the first pages of various heap spaces, to avoid spurious
  matches. If those pointers are not provided, then any matches are
  prefixed with "maybe" in the resulting description string, such as
  "maybe UndefinedValue (0x4288000341 <Oddball>)".

Bug: v8:9376

Change-Id: Iebf3cc2dea3133c7811bcefcdf38d9458b02fded
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1628012
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62882}
2019-07-23 20:02:16 +00:00