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}
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}
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}
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}
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}
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}
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}
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}
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}
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}
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}
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}
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}
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}
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}
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.orgTBR=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}
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}
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}
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}
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}
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}
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}
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}
