Now that we are able to compact map space, we can also get rid of the
map space and allocate maps in the old space instead. This CL introduces
a FLAG_map_space for enabling/disabling the map space but the map space
remains enabled by default for now.
Without a separate space for maps, the GC can't prevent relocation of
maps anymore. Therefore this CL always allows compaction of maps when
running without a map space. Rename flag to --compact-maps to better fit
this scenario.
mkgrokdump and debug_helper also need to be updated to look for maps
also in the old space. The map space is now optional.
Bug: v8:12578
Change-Id: Ic4e4abd0b58bee26e64329b1c92dbccb07d8105a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3424483
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Seth Brenith <seth.brenith@microsoft.com>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79165}
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}
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}
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}
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 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}
