86 Commits

Author SHA1 Message Date
Adrian Prantl
eac2c182c6
Remove a flaky and unnecessary check (#114251)
The order in which the libraries appear is not always stable and even if
it were, this test is not the right place to check for this.
2024-10-30 08:59:08 -07:00
Michael Buch
19f604edfc [lldb][test] Add test for printing std::string through expression evaluator
This would've caught the failures in
https://github.com/llvm/llvm-project/pull/105865 in the libc++
data-formatter CI.
2024-09-11 08:58:03 +01:00
Michael Buch
27d961dab3 [lldb][DataFormatter][test] Move std::string simulator to common libc++ simulators directory 2024-07-16 05:24:30 +01:00
Michael Buch
56c4ec9202
[lldb][test] Add a layout simulator test for std::unique_ptr (#98330)
This is motivated by the upcoming refactor of libc++'s
`__compressed_pair` in https://github.com/llvm/llvm-project/pull/76756

As this will require changes to numerous LLDB libc++ data-formatters
(see early draft https://github.com/llvm/llvm-project/pull/96538), it
would be nice to have a test-suite that will actually exercise both the
old and new layout. We have a matrix bot that tests old versions of
Clang (but currently those only date back to Clang-15). Having them in
the test-suite will give us quicker signal on what broke.

We have an existing test that exercises various layouts of `std::string`
over time in `TestDataFormatterLibcxxStringSimulator.py`, but that's the
only STL type we have it for. This patch proposes a new
`libcxx-simulators` directory which will take the same approach for all
the STL types that we can feasibly support in this way (as @labath
points out, for some types this might just not be possible due to their
implementation complexity). Nonetheless, it'd be great to have a record
of how the layout of libc++ types changed over time.

Some related discussion:
*
https://github.com/llvm/llvm-project/pull/97568#issuecomment-2213426804
2024-07-16 05:21:01 +01:00
Michael Buch
9dca3ac2ef
[lldb][DataFormatter] Simplify libc++ std::map::iterator formatter (#97713)
Depends on https://github.com/llvm/llvm-project/pull/97687

Similar to https://github.com/llvm/llvm-project/pull/97579, this patch
simplifies the way in which we retrieve the key/value pair of a
`std::map` (in this case of the `std::map::iterator`).

We do this for the same reason: not only was the old logic hard to
follow, and encoded the libc++ layout in non-obvious ways, it was also
fragile to alignment miscalculations
(https://github.com/llvm/llvm-project/pull/97443); this would break once
the new layout of std::map landed as part of
https://github.com/llvm/llvm-project/issues/93069.

Instead, this patch simply casts the `__iter_pointer` to the
`__node_pointer` and uses a straightforward
`GetChildMemberWithName("__value_")` to get to the key/value we care
about.

We can eventually re-use the core-part of the `std::map` and
`std::map::iterator` formatters. But it will be an easier to change to
review once both simplifications landed.
2024-07-08 15:56:05 +01:00
Michael Buch
da827d0896
[lldb][DataFormatter] Simplify std::unordered_map::iterator formatter (#97754)
Depends on https://github.com/llvm/llvm-project/pull/97752

This patch changes the way we retrieve the key/value pair in the
`std::unordered_map::iterator` formatter (similar to how we are changing
it for `std::map::iterator` in
https://github.com/llvm/llvm-project/pull/97713, the motivations being
the same).

The old logic was not very easy to follow, and encoded the libc++ layout
in non-obvious ways. But mainly it was also fragile to alignment
miscalculations (https://github.com/llvm/llvm-project/pull/97443); this
would break once the new layout of `std::unordered_map` landed as part
of https://github.com/llvm/llvm-project/issues/93069.

Instead, this patch simply casts the `__hash_iterator` to a
`__node_pointer` (which is what libc++ does too) and uses a
straightforward `GetChildMemberWithName("__value_")` to get to the
key/value we care about.

The `std::unordered_map` already does it this way, so we align the
iterator counterpart to do the same. We can eventually re-use the
core-part of the `std::unordered_map` and `std::unordered_map::iterator`
formatters. But it will be an easier to change to review once both
simplifications landed.
2024-07-08 14:38:58 +01:00
Dmitry Vasilyev
2217d1706a
[lldb][Windows] Fixed LibcxxChronoTimePointSecondsSummaryProvider() (#92701)
This patch fixes #92574. It is a replacement for #92575.
2024-05-20 13:44:52 +04:00
Mark de Wever
a34887550b
[LLDB][libc++] Adds valarray proxy data formatters. (#88613)
These proxies are returned by operator[](...). These proxies all
"behave" the same. They store a pointer to the data of the valarray they
are a proxy for and they have an internal array of indices. This
internal array is considered its contents.
2024-04-15 18:46:58 +02:00
Mark de Wever
e481f56528
[lldb][libc++] Adds local_t clock data formatters. (#88178) 2024-04-13 11:50:02 +02:00
Mark de Wever
56d45b09dc
[lldb][libc++] Adds slice_array data formatters. (#85544)
Co-authored-by: Michael Buch <michaelbuch12@gmail.com>
2024-03-17 14:56:35 +01:00
Jordan Rupprecht
9c2468821e
[lldb][test] Modernize asserts (#82503)
This uses [teyit](https://pypi.org/project/teyit/) to modernize asserts,
as recommended by the [unittest release
notes](https://docs.python.org/3.12/whatsnew/3.12.html#id3).

For example, `assertTrue(a == b)` is replaced with `assertEqual(a, b)`.
This produces better error messages, e.g. `error: unexpectedly found 1
and 2 to be different` instead of `error: False`.
2024-02-21 13:02:30 -06:00
Mark de Wever
5e9eaf87b3
[lldb][libc++] Adds valarray data formatters. (#80609)
The code is heavily based on the vector data formatter.
2024-02-10 20:44:14 +01:00
Adrian Prantl
99446df3f5 Bump the minimum LLVM version for chrono datatformatters tests 2024-02-09 08:13:24 -08:00
Jason Molenda
f219cda7bd
[lldb] Fix printf formatting of std::time_t seconds (#81078)
This formatter
https://github.com/llvm/llvm-project/pull/78609
was originally passing the signed seconds (which can refer to times in
the past) with an unsigned printf formatter, and had tests that expected
to see negative values from the printf which always failed on macOS. I'm
not clear how they ever passed on any platform.

Fix the printf to print seconds as a signed value, and re-enable the
tests.
2024-02-08 09:16:12 -08:00
Jason Molenda
ba45ad160e Temporarily disable two libcxx chrono formatter tests
On macOS, the formatter is printing signed values as
unsigned, it seems, and the tests are expecting correctly
signed values.  These tests were added in
https://github.com/llvm/llvm-project/pull/78609
2024-01-25 16:30:14 -08:00
Mark de Wever
bfd12f39b1
[lldb][libc++] Adds system_clock data formatters. (#78609) 2024-01-22 20:25:14 +01:00
Mark de Wever
e3fde34851
[lldb][libc++] Adds missing C++20 calendar data formatters. (#77954)
This is a followup of #76983 and adds the libc++ data formatters for
- weekday,
- weekday_indexed,
- weekday_last,
- month_weekday,
- month_weekday_last,
- year_month,
- year_month_day_last
- year_month_weekday, and
- year_month_weekday_last.
2024-01-13 13:21:33 +01:00
Mark de Wever
b5f2db9406
[lldb][libc++] Adds some C++20 calendar data formatters. (#76983)
This adds a subset of the C++20 calendar data formatters:
- day,
- month,
- year,
- month_day,
- month_day_last, and
- year_month_day.

A followup patch will add the missing calendar data formatters:
- weekday,
- weekday_indexed,
- weekday_last,
- month_weekday,
- month_weekday_last,
- year_month,
- year_month_day_last
- year_month_weekday, and
- year_month_weekday_last.
2024-01-09 17:19:10 +01:00
Michael Buch
c3f7ca7810
[lldb][Test] TestDataFormatterLibcxxChrono.py: skip test on older clang versions (#70544)
These tests were failing on the LLDB public matrix build-bots for older
clang versions:
```
clang-7: warning: argument unused during compilation: '-nostdlib++' [-Wunused-command-line-argument]
error: invalid value 'c++20' in '-std=c++20'
note: use 'c++98' or 'c++03' for 'ISO C++ 1998 with amendments' standard
note: use 'gnu++98' or 'gnu++03' for 'ISO C++ 1998 with amendments and GNU extensions' standard
note: use 'c++11' for 'ISO C++ 2011 with amendments' standard
note: use 'gnu++11' for 'ISO C++ 2011 with amendments and GNU extensions' standard
note: use 'c++14' for 'ISO C++ 2014 with amendments' standard
note: use 'gnu++14' for 'ISO C++ 2014 with amendments and GNU extensions' standard
note: use 'c++17' for 'ISO C++ 2017 with amendments' standard
note: use 'gnu++17' for 'ISO C++ 2017 with amendments and GNU extensions' standard
note: use 'c++2a' for 'Working draft for ISO C++ 2020' standard
note: use 'gnu++2a' for 'Working draft for ISO C++ 2020 with GNU extensions' standard
make: *** [main.o] Error 1
```

The test fails because we try to compile it with `-std=c++20` (which is
required for std::chrono::{days,weeks,months,years}) on clang versions
that don't support the `-std=c++20` flag.

We could change the test to conditionally compile the C++20 parts of the
test based on the `-std=` flag and have two versions of the python
tests, one for the C++11 chrono features and one for the C++20 features.

This patch instead just disables the test on older clang versions
(because it's simpler and we don't really lose important coverage).
2023-10-30 17:08:25 +00:00
Mark de Wever
0e4264ab1e [lldb][libc++] Adds chrono data formatters.
This adds the data formatters for chrono duration typedefs.

Reviewed By: Michael137

Differential Revision: https://reviews.llvm.org/D159127
2023-10-25 19:36:47 +02:00
Michael Buch
487ab39a50 [lldb][test] Remove tests relying on deprecated std::char_traits specializations
(motivated by test failures after D157058)

With D157058 the base template for `std::char_traits` was removed from
libc++. Quoting the release notes:

```
The base template for ``std::char_traits`` has been removed. If you are using
``std::char_traits`` with types other than ``char``, ``wchar_t``, ``char8_t``,
``char16_t``, ``char32_t`` or a custom character type for which you
specialized ``std::char_traits``, your code will no longer work.
```

This patch simply removes all such instantiations to make sure the
tests that run against the latest libc++ version pass.

One could try testing the existence of this base template from within
the test source files but this doesn't seem like something we want
support.

Differential Revision: https://reviews.llvm.org/D157636
2023-08-10 19:48:44 +01:00
Jonas Devlieghere
2238dcc393
[NFC][Py Reformat] Reformat python files in lldb
This is an ongoing series of commits that are reformatting our Python
code. Reformatting is done with `black` (23.1.0).

If you end up having problems merging this commit because you have made
changes to a python file, the best way to handle that is to run `git
checkout --ours <yourfile>` and then reformat it with black.

RFC: https://discourse.llvm.org/t/rfc-document-and-standardize-python-code-style

Differential revision: https://reviews.llvm.org/D151460
2023-05-25 12:54:09 -07:00
Jorge Gorbe Moya
d69518b4e5 Re-land "[lldb] Make the libcxx unique_ptr prettyprinter support custom deleters."
This reverts commit 45351120105a7257ccb1e38ec1b1f8a452269da2.
2023-05-01 16:19:01 -07:00
Jorge Gorbe Moya
4535112010 Revert "[lldb] Make the libcxx unique_ptr prettyprinter support custom deleters."
This reverts commit d366da97bd24ddfb91c9f260fa0aaf105d947652.
2023-05-01 14:14:09 -07:00
Jorge Gorbe Moya
d366da97bd [lldb] Make the libcxx unique_ptr prettyprinter support custom deleters.
The unique_ptr prettyprinter calls `GetValueOfLibCXXCompressedPair`,
which looks for a `__value_` child. However, when the second value in
the compressed pair is not an empty class, there are two `__value_`
children because `__compressed_pair` derives twice from
`__compressed_pair_elem`, one for each member of the pair. And then the
lookup fails because it's ambiguous.

This patch makes the following changes:

- Rename `GetValueOfLibCXXCompressedPair` to
  `GetFirstValueOfLibCXXCompressedPair`, and add a similar function to
  get the second value. Put both functions in
  Plugin/Language/CPlusPlus/LibCxx.cpp because it seems inappropriate to
  have libcxx-specific helpers separate from all the libcxx-dependent
  code.

- Read the second value of the `__ptr_` pair and display a "deleter"
  child in the unique_ptr synthetic child provider, when available.

- Add a test case for the non-empty deleter case.

Differential Revision: https://reviews.llvm.org/D148662
2023-05-01 13:08:04 -07:00
Jorge Gorbe Moya
3c91d01634 [lldb] Build libcxx unique_ptr and shared_ptr test programs with -glldb.
The functionality added by https://reviews.llvm.org/D145803 is gated by
lldb tuning, so we need to build the test programs with `-glldb` to make
these tests print the expected preferred name.

Differential Revision: https://reviews.llvm.org/D148582
2023-04-17 17:03:29 -07:00
Michael Buch
1414a5bdfe [lldb][DataFormatter] Fix libcxx std::deque formatter for references and pointers
(Addresses GH#62153)

The `SBType` APIs to retrieve details about template arguments,
such as `GetTemplateArgumentType` or `GetTemplateArgumentKind`
don't "desugar" LValueReferences/RValueReferences or pointers.
So when we try to format a `std::deque&`, the python call to
`GetTemplateArgumentType` fails to get a type, leading to
an `element_size` of `0` and a division-by-zero python exception
(which gets caught by the summary provider silently). This leads
to the contents of such `std::deque&` to be printed incorrectly.

This patch dereferences the reference/pointer before calling
into the above SBAPIs.

**Testing**

* Add API test

Differential Revision: https://reviews.llvm.org/D148531
2023-04-17 21:31:30 +01:00
Michael Buch
711a644127 [clang][DebugInfo] Emit DW_AT_type of preferred name if available
With this patch, whenever we emit a `DW_AT_type` for some declaration
and the type is a template class with a `clang::PreferredNameAttr`, we
will emit the typedef that the attribute refers to instead. I.e.,

```
0x123 DW_TAG_variable
        DW_AT_name "var"
        DW_AT_type (0x123 "basic_string<char>")

0x124 DW_TAG_structure_type
        DW_AT_name "basic_string<char>"
```
...becomes
```
0x123 DW_TAG_variable
        DW_AT_name "var"
        DW_AT_type (0x124 "std::string")

0x124 DW_TAG_structure_type
        DW_AT_name "basic_string<char>"

0x125 DW_TAG_typedef
        DW_AT_name "std::string"
        DW_AT_type (0x124 "basic_string<char>")
```

We do this by returning the preferred name typedef `DIType` when
we create a structure definition. In some cases, e.g., with `-gmodules`,
we don't complete the structure definition immediately but do so later
via `completeClassData`, which overwrites the `TypeCache`. In such cases
we don't actually want to rewrite the cache with the preferred name. We
handle this by returning both the definition and the preferred typedef
from `CreateTypeDefinition` and let the callee decide what to do with
it.

Essentially we set up the types as:
```
TypeCache[Record] => DICompositeType
ReplaceMap[Record] => DIDerivedType(baseType: DICompositeType)
```

For now we keep this behind LLDB tuning.

**Testing**

- Added clang unit-test
- `check-llvm`, `check-clang` pass
- Confirmed that this change correctly repoints
  `basic_string` references in some of my test programs.
- Will add follow-up LLDB API tests

Differential Revision: https://reviews.llvm.org/D145803
2023-04-07 01:37:36 +01:00
Michael Buch
ad81d019a6 [lldb][Test] Check compiler in data forammter compiler version checks
**Summary**

The compiler version check wouldn't make sense for non-GCC
compilers, so check for the compiler too.

Differential Revision: https://reviews.llvm.org/D143656
2023-02-10 01:37:26 +00:00
Michael Buch
3c66729887 [lldb][Test] Fix import-std-module and data-formatter tests on older compilers
Fixes API tests for older compilers.
Since https://reviews.llvm.org/D141828 defaulted
arguments will be omitted, but older Clang's won't.

Differential Revision: https://reviews.llvm.org/D143022
2023-02-02 11:34:07 +00:00
Michael Buch
ce6a56e667 Reland "[lldb] Add support for DW_AT_default_value in template params"
**Summary**

This patch makes LLDB understand the `DW_AT_default_value` on
template argument DIEs. As a result, type summaries will no
longer contain the defaulted template arguments, reducing
noise substantially. E.g.,

Before:
```
(lldb) v nested
(std::vector<std::vector<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > >, std::allocator<std::vector<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::basic_string<char, std::char_traits<char>, std::allocator <char> > > > > >) nested = size=0 {}
```

After:
```
(lldb) v nested
(std::vector<std::vector<std::basic_string<char> > >) nested = size=0 {}
```

See discussion in https://reviews.llvm.org/D140423

**Testing**

* Adjust API tests
* Added unit-test

Differential Revision: https://reviews.llvm.org/D141828
2023-01-27 22:49:46 +00:00
Dave Lee
47f0384bb9 [lldb][test] Set minimum compiler_versions
Set compiler_versions on these tests, as they fail if tested on lower compiler
versions versions.

Differential Revision: https://reviews.llvm.org/D142513
2023-01-27 14:29:45 -08:00
David Spickett
1efde67d99 Revert "[lldb] Add support for DW_AT_default_value in template params"
This reverts commit 1cf52e540242f968e0cf789587bcf76c01332aeb.

Due to test failures on Arm and AArch64 bots:
https://lab.llvm.org/buildbot/#/builders/96/builds/34718

(which were obscured by an earlier build failure)
2023-01-27 11:36:42 +00:00
Michael Buch
1aee040c65 [lldb] Add support for DW_AT_default_value in template params
**Summary**

This patch makes LLDB understand the `DW_AT_default_value` on
template argument DIEs. As a result, type summaries will no
longer contain the defaulted template arguments, reducing
noise substantially. E.g.,

Before:
```
(lldb) v nested
(std::vector<std::vector<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > >, std::allocator<std::vector<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::allocator<std::basic_string<char, std::char_traits<char>, std::allocator <char> > > > > >) nested = size=0 {}
```

After:
```
(lldb) v nested
(std::vector<std::vector<std::basic_string<char> > >) nested = size=0 {}
```

See discussion in https://reviews.llvm.org/D140423

**Testing**

* Adjust API tests
* Added unit-test

Differential Revision: https://reviews.llvm.org/D141828
2023-01-27 02:24:36 +00:00
Dave Lee
4076664228 [lldb][test] Replace use of p with expression (NFC)
In API tests, replace use of the `p` alias with the `expression` command.

To avoid conflating tests of the alias with tests of the expression command,
this patch canonicalizes to the use `expression`.

Differential Revision: https://reviews.llvm.org/D141539
2023-01-25 11:03:58 -08:00
Michael Buch
9bfc8ba7a7 [lldb][Test] TestDataFormatterLibcxxRangesRefView.py: skip on old compiler versions
`std::ranges` are only available in libcxx shipped with Clang > 15.0
2023-01-03 13:12:31 +00:00
Jordan Rupprecht
3c51ea3619 [DataFormatter] Fix variant npos with _LIBCPP_ABI_VARIANT_INDEX_TYPE_OPTIMIZATION enabled.
This data formatter should print "No Value" if a variant is unset. It does so by checking if `__index` has a value of `-1`, however it does so by interpreting it as a signed int.

By default, `__index` has type `unsigned int`. When `_LIBCPP_ABI_VARIANT_INDEX_TYPE_OPTIMIZATION` is enabled, the type of `__index` is either `unsigned char`, `unsigned short`, or `unsigned int`, depending on how many fields there are -- as small as possible. For example, when `std::variant` has only a few types, the index type is `unsigned char`, and the npos value will be interpreted by LLDB as `255` when it should be `-1`.

This change does not special case the variant optimization; it just reads the type instead of assuming it's `unsigned int`.

Reviewed By: labath

Differential Revision: https://reviews.llvm.org/D138892
2022-11-30 13:20:13 -08:00
Michael Buch
77b2205245 [lldb][DataFormatter] Add std::ranges::ref_view formatter
This patch adds a formatter for `std::ranges::ref_view<T>`.
It simply holds a `T*`, so all this formatter does is dereference
this pointer and format it as `T` would be.

**Testing**

* Added API tests

Differential Revision: https://reviews.llvm.org/D138558
2022-11-30 14:39:39 +00:00
Jordan Rupprecht
7d26f9e132 [test] Allow libc++ namespaces besides __1
The libc++ data formatter for `std::shared_ptr` allows any namespace, but the test asserts that it must be the default `__1` namespace. Relax the regex to allow anything that looks like `__.*` (although we use `__[^:]*` so we don't match arbitrarily long text).

Reviewed By: labath

Differential Revision: https://reviews.llvm.org/D129898
2022-11-29 04:34:40 -08:00
Jordan Rupprecht
3c10e9c773 [test] Implement layout for unstable std::string garbage formatter tests.
The layout is essentially just reversed from the stable std::string layout.

Reviewed By: labath

Differential Revision: https://reviews.llvm.org/D138850
2022-11-29 04:22:30 -08:00
Adrian Prantl
79e522fb44 Revert "Skip crashing test"
This reverts commit c1ce19021da0cf1c88722024e6ff9cee7aabc7b6.
2022-09-26 17:17:47 -07:00
Adrian Prantl
8599cb002b Skip crashing test 2022-09-12 09:48:42 -07:00
Adrian Prantl
2f4a66eed6 Adapt LLDB dataformatters for libcxx change D129386
Differential Revision: https://reviews.llvm.org/D133618
2022-09-09 15:58:55 -07:00
Adrian Prantl
c988965efb Temporarily XFAIL libcxx tests.
These tests started failing on green dragon after a configuration change that compiles tests using the just-built libcxx. We may need to force the system libcxx here, or change LLDB to import the std module from the just-built libcxx, too.
2022-09-09 10:43:03 -07:00
David Spickett
193259cbce [LLDB] Remove __future__ imports from tests
Not needed now that we require python 3.

Reviewed By: kastiglione, JDevlieghere

Differential Revision: https://reviews.llvm.org/D131761
2022-08-15 08:54:06 +00:00
Michael Buch
6703812688 [LLDB][DataFormatter] Add support for std::__map_const_iterator
This patch adds support for formatting `std::map::const_iterator`.
It's just a matter of adding `const_` to the existing regex.

**Testing**

* Added test case to existing API tests

Differential Revision: https://reviews.llvm.org/D129962
2022-07-21 14:21:12 +01:00
Michael Buch
d1e9d0b27f [LLDB][DataFormatter] Add data formatter for libcxx std::unordered_map iterator
This patch adds a formatter for libcxx's `std::unordered_map` iterators.
The implementation follows a similar appraoch to the `std::map` iterator
formatter. I was hesistant about coupling the two into a common
implementation since the libcxx layouts might change for one of the
the containers but not the other.

All `std::unordered_map` iterators are covered with this patch:
1. const/non-const key/value iterators
2. const/non-const bucket iterators

Note that, we currently don't have a formatter for `std::unordered_map`.
This patch doesn't change that, we merely add support for its iterators,
because that's what Xcode users requested. One can still see contents
of `std::unordered_map`, whereas with iterators it's less ergonomic.

**Testing**

* Added API test

Differential Revision: https://reviews.llvm.org/D129364
2022-07-12 10:13:55 +01:00
Dave Lee
4655400b21 [lldb] Delete more mydir references (NFC) 2022-07-10 18:56:06 -07:00
Pavel Labath
8262ff44c5 [lldb/test] Add a couple of libc++ std::string layouts
.. to the "string simulator" test. These layouts were used at some point in
the past few months, and are already supported by the code.
2022-07-07 16:20:20 +02:00
Pavel Labath
b6b65403b3 [lldb] Add tests which simulate the various std::string layouts
Checking whether a formatter change does not break some of the supported
string layouts is difficult because it requires tracking down and/or
building different versions and build configurations of the library.

The purpose of this patch is to avoid that by providing an in-tree
simulation of the string class. It is a reduced version of the real
string class, obtained by elimitating all non-trivial code, leaving
just the internal data structures used by the data formatter. Different
versions of the class can be simulated through preprocessor defines.

The test (ab)uses the fact that our formatters kick in for any
double-underscore sub-namespace of `std`, so it avoids colliding with
the real string class by declaring the test class in the std::__lldb
namespace.

I do not consider this to be a replacement for the existing data
formatter tests, as producing this kind of a test is not trivial, and it
is easy to make a mistake in the process. However, it's also not
realistic to expect that every person changing the data formatter will
test it against all versions of the real class, so I think it can be
useful as a first line of defence.

Adding support for new layouts can become particularly unwieldy, but
this complexity will also be reflected in the actual code, so if we find
ourselves needing to support too many variants, we may need to start
dropping support for old ones, or come up with a completely different
strategy.

Differential Revision: https://reviews.llvm.org/D124155
2022-07-01 08:08:22 +02:00