Commit Graph

1065 Commits

Author SHA1 Message Date
Louis Dionne 4f194d0db7 [libc++] Promote GCC 11 to mandatory CI
Also, fix the last issue that prevented GCC 11 from passing the test
suite. Thanks to everyone else who fixed issues.

Differential Revision: https://reviews.llvm.org/D104315
2021-06-15 20:54:58 -04:00
Xing Xue ecb68f1c8b [libc++abi] NFC: avoid a -Wunused-parameter warning
Summary:
A -Wunused-parameter warning was introduced by patch rG7f0244afa828 [libc++abi] NFC: adding a new parameter base to functions for calculating… (authored by xingxue). The unused parameter base will be used in a follow-on patch D101298. This patch is to avoid the warning before D101298 is landed.

Reviewers: ldionne, sfertile, compnerd, libc++abi

Reviewed by: ldionne

Differential Revision: https://reviews.llvm.org/D104235
2021-06-14 16:04:02 -04:00
Louis Dionne a0ae3b0789 [libc++abi] Remove the LIBCXXABI_ENABLE_PIC option
Instead, people should be using CMAKE_POSITION_INDEPENDENT_CODE to control
whether they want to use PIC or not. We should try to avoid reinventing
the wheel whenever CMake natively supports something.

This makes libc++abi consistent with libc++ and libunwind.

Differential Revision: https://reviews.llvm.org/D103973
2021-06-10 12:26:31 -04:00
Xing Xue 7f0244afa8 [libc++abi] NFC: adding a new parameter base to functions for calculating addresses with relative encodings
Summary:
    This NFC patch adds a new parameter base to functions invoked by scan_eh_tab() for calculating the address of the encoding with a relative value. base defaults to 0. This is in preparation for the AIX implementation which uses the DW_EH_PE_datarel encoding.

    Reviewed by: MaskRay, sfertile, compnerd, libc++abi

    Differential Revision: https://reviews.llvm.org/D101545
2021-06-10 10:45:50 -04:00
Justin Lebar c962491a41
Save/restore OuterTemplateParams in AbstractManglingParser::parseEncoding.
Previously we were only saving plain TemplateParams.

Differential Revision: https://reviews.llvm.org/D103996
2021-06-09 17:56:23 -07:00
Louis Dionne 875ff8e059 [libc++] Enable tests for the experimental library by default
This matches the fact that we build the experimental library by default.
Otherwise, by default we'd be building the library but not testing it,
which is inconsistent.

Differential Revision: https://reviews.llvm.org/D102109
2021-06-02 18:39:27 -04:00
Shoaib Meenai a051bbb53f [libcxxabi] Use ASan interface header for declaration. NFC
This was changed from using the header to using a forward declaration in
c4600ccf89, since older versions of the header didn't declare the
function. At this point, it's been declared for ~3.5 years, and it
should be pretty safe to assume that we can rely on the ASan interface
header to provide a declaration instead of needing to write our own.

Reviewed By: #libc_abi, ldionne

Differential Revision: https://reviews.llvm.org/D103003
2021-05-25 13:07:13 -07:00
Shoaib Meenai 6c05f2dab3 [libcxxabi] Remove unnecessary define from build
Now that we're passing -D_LIBCPP_BUILDING_LIBRARY to the libc++abi
build, -D_LIBCPP_ENABLE_CXX17_REMOVED_UNEXPECTED_FUNCTIONS is redundant
(fb3a00c327/libcxx/include/exception (L120-L121)
is the only use of _LIBCPP_ENABLE_CXX17_REMOVED_UNEXPECTED_FUNCTIONS in
libc++, and that conditional also checks for _LIBCPP_BUILDING_LIBRARY).

Reviewed By: #libc_abi, phosek

Differential Revision: https://reviews.llvm.org/D102372
2021-05-20 16:56:05 -07:00
Louis Dionne 74d096e558 [libc++] Move handling of the target triple to the DSL
This fixes a long standing issue where the triple is not always set
consistently in all configurations. This change also moves the
back-deployment Lit features to using the proper target triple
instead of using something ad-hoc.

This will be necessary for using from scratch Lit configuration files
in both normal testing and back-deployment testing.

Differential Revision: https://reviews.llvm.org/D102012
2021-05-08 11:10:53 -04:00
Petr Hosek ea12d779bc [libc++] Support per-target __config_site in per-target runtime build
When using the per-target runtime build, it may be desirable to have
different __config_site headers for each target where all targets cannot
share a single configuration.

The layout used for libc++ headers after this change is:

```
include/
  c++/
    v1/
      <libc++ headers except for __config_site>
  <target1>/
    c++/
      v1/
        __config_site
  <target2>/
    c++/
      v1/
        __config_site
  <other targets>
```

This is the most optimal layout since it avoids duplication, the only
headers that's per-target is __config_site, all other headers are
shared across targets. This also means that we no need two
-isystem flags: one for the target-agnostic headers and one for
the target specific headers.

Differential Revision: https://reviews.llvm.org/D89013
2021-04-28 14:27:16 -07:00
Tomasz Miąsko 1cea7ab4ba [demangler] Use standard semantics for StringView::substr
The StringView::substr now accepts a substring starting position and its
length instead of previous non-standard `from` & `to` positions.

All uses of two argument StringView::substr are in MicrosoftDemangler
and have 0 as a starting position, so no changes are necessary.

This also fixes a bug where attempting to extract a suffix with substr
(a `to` position equal to size) would return a substring without the
last character.

Fixing the issue should not introduce observable changes in the
demangler, since as currently used, a second argument to
StringView::substr is either: 1) a result of a successful call to
StringView::find and so necessarily smaller than size., or 2) in the
case of Demangler::demangleCharLiteral potentially equal to size, but
with demangler expecting more data to follow later on and failing either
way.

Reviewed By: #libc_abi, ldionne, erik.pilkington

Differential Revision: https://reviews.llvm.org/D100246
2021-04-25 13:56:41 +02:00
Petr Hosek f749550cfe [libcxx] Stop using use c++ subdirectory for libc++ library
The new layout more closely matches the layout used by other compilers.
This is only used when LLVM_ENABLE_PER_TARGET_RUNTIME_DIR is enabled.

Differential Revision: https://reviews.llvm.org/D100869
2021-04-21 15:39:03 -07:00
Louis Dionne 4cd6ca102a [libc++] NFC: Normalize `#endif //` comment indentation 2021-04-20 12:03:32 -04:00
Louis Dionne 2da6ce60a5 [libc++abi] Adjust XFAIL for misaligned exception header on ARM
On ARM, the alignment has always been the right one, so this test never
fails.
2021-04-07 16:14:50 -04:00
Petr Hosek 96d8c6b571 [CMake] Remove {LIBCXX,LIBCXXABI,LIBUNWIND}_INSTALL_PREFIX
These variables were introduced during early work on the runtimes build
but were obsoleted by {LIBCXX,LIBCXXABI,LIBUNWIND}_INSTALL_LIBRARY_DIR.

Differential Revision: https://reviews.llvm.org/D99697
2021-04-01 10:13:07 -07:00
Louis Dionne c06a8f9caa [libc++] Include <__config_site> from <__config>
Prior to this patch, we would generate a fancy <__config> header by
concatenating <__config_site> and <__config>. This complexifies the
build system and also increases the difference between what's tested
and what's actually installed.

This patch removes that complexity and instead simply installs <__config_site>
alongside the libc++ headers. <__config_site> is then included by <__config>,
which is much simpler. Doing this also opens the door to having different
<__config_site> headers depending on the target, which was impossible before.

It does change the workflow for testing header-only changes to libc++.
Previously, we would run `lit` against the headers in libcxx/include.
After this patch, we run it against a fake installation root of the
headers (containing a proper <__config_site> header). This makes use
closer to testing what we actually install, which is good, however it
does mean that we have to update that root before testing header changes.
Thus, we now need to run `ninja check-cxx-deps` before running `lit` by
hand.

Differential Revision: https://reviews.llvm.org/D97572
2021-03-30 14:06:11 -07:00
Petr Hosek 1687f2bbe2 [libcxxabi] Use cxx-headers target to consume libcxx headers
Rather than including libc++ include dir, use the cxx-headers target.

Differential Revision: https://reviews.llvm.org/D98367
2021-03-26 13:27:51 -07:00
Petr Hosek 74ed5124ba Revert "[libcxxabi] Use cxx-headers target to consume libcxx headers"
This reverts commit 72728e1280
which broke libcxxabi tests under the runtimes build.
2021-03-25 01:50:11 -07:00
jasonliu 158026301b [libc++][AIX] Initial patch to unblock the libc++ build on AIX
This path would unblock the build of libc++ library on AIX:
1. Add _AIX guard for _LIBCPP_HAS_THREAD_API_PTHREAD
2. Use uselocale to actually take the locale setting
   into account.
3. extract_mtime and extract_atime mod needed for AIX. As stat
   structure on AIX uses internal structure st_timespec to store
   time for binary compatibility reason. So we need to convert it
   back to timespec here.
4. Do not build cxa_thread_atexit.cpp for libcxxabi on AIX.

Differential Revision: https://reviews.llvm.org/D97558
2021-03-24 22:13:20 +00:00
Alex Orlov 876435c487 * Fix demangling of optional template-args for vendor extended type qualifier.
This fixes https://bugs.llvm.org/show_bug.cgi?id=48009 bug.

Reviewed By: erik.pilkington, krisb

Differential Revision: https://reviews.llvm.org/D98687
2021-03-24 10:21:32 +04:00
Petr Hosek 72728e1280 [libcxxabi] Use cxx-headers target to consume libcxx headers
Rather than including libc++ include dir, use the cxx-headers target.

Differential Revision: https://reviews.llvm.org/D98367
2021-03-23 12:25:30 -07:00
Markus Böck 6359049c35 [CMake][runtimes] Add file level dependency to merge_archives commands
Both libc++ and libc++abi have options of merging with another archive. In the case of libc++abi, libunwind can be merged into it and in the case of libc++, libc++abi can be merged into it.

This is realized using add_custom_command with POST_BUILD and the usage of the CMake generator expression TARGET_LINKER_FILE in the arguments. For such generator expressions CMake doc states: "This target-level dependency does NOT add a file-level dependency that would cause the custom command to re-run whenever the executable is recompiled" [1]

This patch adds a DEPENDS argument to both add_custom_command invocations so that the archives also have a file-level dependency on the target they are merging with. That way, changes in say, libunwind source code, will be updated in the libc++abi and/or libc++ static libraries as well.

[1] https://cmake.org/cmake/help/v3.20/command/add_custom_command.html

Differential Revision: https://reviews.llvm.org/D98129
2021-03-18 18:51:10 +01:00
Petr Hosek e1173c8794 [runtimes] Use add_lit_testsuite to register lit testsuites
The runtimes build uses variables set by add_lit_testsuite to collect
testsuites from all the runtimes.

Differential Revision: https://reviews.llvm.org/D97913
2021-03-05 10:37:21 -08:00
Markus Böck 05b3716ddb [libcxxabi] Add LIBCXXABI_HAS_WIN32_THREAD_API build option
A few files in libc++abi make use of libc++ headers and a few of those use threading primitives provided by libc++. Since libc++ has multiple threading APIs it may be necessary to override auto-detection.

This patch adds the LIBCXXABI_HAS_WIN32_THREAD_API which does roughly the same as LIBCXXABI_HAS_PTHREAD_API and the similarly named LIBCXX_HAS_WIN32_THREAD_API from libc++. Instead of using autodetection it will force the use of win32 threads instead of pthreads in headers included from libc++.

Without this patch, libc++abi may depend on pthreads if present on the users build environment, even if win32 threading was selected for libc++.

Differential revision: https://reviews.llvm.org/D98021
2021-03-05 15:30:13 +01:00
Louis Dionne 5601305fb3 [libc++/abi] Replace uses of _NOEXCEPT in src/ by noexcept
We always build the libraries in a Standard mode that supports noexcept,
so there's no need to use the _NOEXCEPT macro.

Differential Revision: https://reviews.llvm.org/D97700
2021-03-03 12:57:31 -05:00
Louis Dionne 60ba1fefab [libc++/abi] Allow running back-deployment testing against libc++abi
Before this patch, we could only link against the back-deployment libc++abi
dylib. This patch allows linking against the just-built libc++abi, but
running against the back-deployment one -- just like we do for libc++.

Also, add XFAIL markup to flag expected errors.

Differential Revision: https://reviews.llvm.org/D91069
2021-03-01 12:13:03 -05:00
Nico Weber 72b18a86e1 [libcxxabi] Fewer assumptions about path from libcxx to libcxxabi
This is useful for projects that pull in libcxx and libcxxabi and build
them using out-of-tree build files, but don't make them sibling
directories (or don't call the sibling directories libcxx and libcxxabi
for some reason).

Fixes PR49313.

Differential Revision: https://reviews.llvm.org/D97379
2021-02-26 09:10:18 -05:00
Patrick Oppenlander 26a0aeba61 [libc++abi] Add builtins to dynamic library link
Otherwise libc++abi.so fails to link on arm with undefined references to
some __aeabi_ builtins.

Differential Revision: https://reviews.llvm.org/D96574
2021-02-17 17:05:59 -05:00
Zbigniew Sarbinowski 5f9be2c3e3 [SystemZ][ZOS] Prefer -nostdlib++ as opposed to -nodefaultlibs when building c++ libraries
Let's use -nostdlib++ rather than -nodefaultlibs when building libc++/libc++abi/libunwind libraries. The default is -nostdlib++ if supported by a build compiler like it is the case with clang, otherwise -nodefaultlibs is used as before.

This change is needed to avoid additional changes at the link step and not to increase the maintenance costs. If clang with -nodefaultlibs is used all the libraries which are removed but required would have to be manually added in. This set of libraries are unique and will send out.

The propose change will allow to make the link step simple for other platforms as well.

Reviewed By: #libc, #libc_abi, ldionne

Differential Revision: https://reviews.llvm.org/D95875
2021-02-16 18:42:14 +00:00
Vladimir Vereschaka c40b83199f [libc++abi] Fix forced_unwind tests failures on ARM/EHABI targets.
Added __cxxabi_config.h includes to resolve _LIBCXXABI_ARM_EHABI and
proper building the forces_unwindX.cpp tests for the ARM/EHABI targets.

Differential Revision: https://reviews.llvm.org/D96378
2021-02-12 13:58:41 -08:00
Fangrui Song a4fa667dee [libc++abi] Disable _Unwind_ForcedUnwind + exception tests for ARM EHABI
libunwind ARM EHABI does not support _Unwind_ForcedUnwind yet.
In addition, ARM EHABI makes `_Unwind_Exception` a typedef so
`struct _Unwind_Exception*` cannot be used.
2021-02-05 14:12:27 -08:00
Fangrui Song 81af8149d8 [test] Add basic _Unwind_ForcedUnwind + exception tests
Forced unwinding is like a foreign exception, which can be caught by `catch (...)` and rethrown.
If not rethrown, `__cxa_end_cath` will call `_Unwind_DeleteException` to destroy the object.

The behavior going through empty `throw()` and non-empty `throw(int)` is not
clear (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98785), so I do not add such
tests.

Differential Revision: https://reviews.llvm.org/D95200
2021-02-02 09:35:27 -08:00
xgupta 94fac81fcc [Branch-Rename] Fix some links
According to the [[ https://foundation.llvm.org/docs/branch-rename/ | status of branch rename ]], the master branch of the LLVM repository is removed on 28 Jan 2021.

Reviewed By: mehdi_amini

Differential Revision: https://reviews.llvm.org/D95766
2021-02-01 16:43:21 +05:30
James Y Knight 9c7aeaebb3 Itanium Mangling: Mangle `__alignof__` differently than `alignof`.
The two operations have acted differently since Clang 8, but were
unfortunately mangled the same. The new mangling uses new "vendor
extended expression" syntax proposed in
https://github.com/itanium-cxx-abi/cxx-abi/issues/112

GCC had the same mangling problem, https://gcc.gnu.org/PR88115, and
will hopefully be switching to the same mangling as implemented here.

Additionally, fix the mangling of `__uuidof` to use the new extension
syntax, instead of its previous nonstandard special-case.

Adjusts the demangler accordingly.

Differential Revision: https://reviews.llvm.org/D93922
2021-01-27 16:46:51 -05:00
Marek Kurdej 5e7a93a954 [libc++] Set CMAKE_FOLDER. NFC.
* This variable populates the default value of FOLDER target property. It is used in some IDE's (e.g. MSVC) to group different targets together.
2021-01-25 09:51:16 +01:00
Fangrui Song cfe9ccbddd [libc++abi] Simplify scan_eh_tab
1.
All `_URC_HANDLER_FOUND` return values need to set `landingPad`
and its value does not matter for `_URC_CONTINUE_UNWIND`. So we
can always set `landingPad` to unify code.

2.
For an exception specification (`ttypeIndex < 0`), we can check `_UA_FORCE_UNWIND` first.

3.
The so-called type 3 search (`actions & _UA_CLEANUP_PHASE && !(actions & _UA_HANDLER_FRAME)`)
is actually conceptually wrong.  For a catch handler or an unmatched dynamic
exception specification, `_UA_HANDLER_FOUND` should be returned immediately.  It
still appeared to work because the `ttypeIndex==0` case would return
`_UA_HANDLER_FOUND` at a later time.

This patch fixes the conceptual error and simplifies the code by handling type 3
the same way as type 2 (which is also what libsupc++ does).
The only difference between phase 1 and phase 2 is what to do with a cleanup
(`actionEntry==0`, or a `ttypeIndex==0` is found in the action record chain):
phase 1 returns `_URC_CONTINUE_UNWIND` while phase 2 returns `_URC_HANDLER_FOUND`.

Reviewed By: #libc_abi, compnerd

Differential Revision: https://reviews.llvm.org/D93190
2021-01-21 15:19:23 -08:00
Dan Albert 866d480fe0 [libc++abi] Add an option to avoid demangling in terminate.
We've been using this patch in Android so we can avoid including the
demangler in libc++.so. It comes with a rather large cost in RSS and
isn't commonly needed.

Reviewed By: #libc_abi, compnerd

Differential Revision: https://reviews.llvm.org/D88189
2021-01-21 13:32:29 -08:00
Raul Tambre 480643a95c [CMake] Remove dead code setting policies to NEW
cmake_minimum_required(VERSION) calls cmake_policy(VERSION),
which sets all policies up to VERSION to NEW.
LLVM started requiring CMake 3.13 last year, so we can remove
a bunch of code setting policies prior to 3.13 to NEW as it
no longer has any effect.

Reviewed By: phosek, #libunwind, #libc, #libc_abi, ldionne

Differential Revision: https://reviews.llvm.org/D94374
2021-01-19 17:19:36 +02:00
Louis Dionne bc556e5685 [libc++/abi] Re-remove unnecessary null pointer checks from operator delete
In 7cd67904f7, we removed the unnecessary nullptr checks from the libc++abi
definition of operator delete, but we forgot to update the definition in
libc++ (damn code duplication!). Then, in d4a1e03c5f, I synced the
definitions across libc++ and libc++abi, but I did it the wrong way around.
I re-added the if() checks to libc++abi instead of removing them from libc++.

In ef74f0fdc3, we re-removed the if() check from operator delete, but
only in libc++abi. This patch corrects this mess and removes it
consistently in libc++ and libc++abi.

Differential Revision: https://reviews.llvm.org/D93473
2021-01-08 17:03:50 -05:00
Fangrui Song 85f86e8a3c [libc++abi] Simplify __gxx_personality_v0
In three cases we call `scan_eh_tab` to parse LSDA:

* `actions & _UA_SEARCH_PHASE`
* `actions & _UA_CLEANUP_PHASE && actions & _UA_HANDLER_FRAME && !native_exception`
* `actions & _UA_CLEANUP_PHASE && !(actions & _UA_HANDLER_FRAME)`

Check
`actions & _UA_CLEANUP_PHASE && actions & _UA_HANDLER_FRAME && native_exception` first,
then we can move three `scan_eh_tab` into one place.

Another simplification is that we can check whether the result of `scan_eh_tab`
is `_UA_CONTINUE_UNWIND` or `_UA_FATAL_PHASE1_ERROR` first. Then many of the
original checks will be dead and can thus be deleted.

Reviewed By: #libc_abi, ldionne

Differential Revision: https://reviews.llvm.org/D93186
2021-01-07 14:05:46 -08:00
Fangrui Song ef74f0fdc3 [libc++abi] Remove redundant null pointer check in operator delete
Similar to D52401. Normally operator delete is defined in libc++abi
(LIBCPP_DISABLE_NEW_DELETE_DEFINITIONS is off by default).

C89 4.10.3.2 The free function
C99 7.20.3.2 The free function
C11 7.22.3.3 The free function

    If ptr is a null pointer, no action shall occur.

free on MSDN:

    If memblock is NULL, the pointer is ignored and free immediately returns.

Reviewed By: #libc_abi, ldionne

Differential Revision: https://reviews.llvm.org/D93339
2020-12-16 13:29:40 -08:00
Louis Dionne d67e58f23a [libc++abi] Don't try calling __libcpp_aligned_free when aligned allocation is disabled
See https://reviews.llvm.org/rGa78aaa1ad512#962077 for details.
2020-12-01 17:45:14 -05:00
Leonard Chan 61aec69a65 [libcxxabi] Add macro for changing functions to support the relative vtables ABI
Under the relative vtables ABI, __dynamic_cast will not work since it assumes
the vtable pointer is 2 ptrdiff_ts away from the start of the vtable (8-byte
offset to top + 8-byte pointer to typeinfo) when it is actually 8 bytes away
(4-byte offset to top + 4-byte offset to typeinfo). This adjusts the logic under
__dynamic_cast and other areas vtable calculations are done to support this ABI
when it's used.

Differential Revision: https://reviews.llvm.org/D77606
2020-11-30 10:50:05 -08:00
Louis Dionne 564628014c [libc++] Introduce an indirection to create threads in the test suite
We create threads using std::thread in various places in the test suite.
However, the usual std::thread constructor may not work on all platforms,
e.g. on platforms where passing a stack size is required to create a thread.

This commit introduces a simple indirection that makes it easier to tweak
how threads are created inside the test suite on various platforms. Note
that tests that are purposefully calling std::thread's constructor directly
(e.g. because that is what they're testing) were not modified.
2020-11-27 11:54:19 -05:00
Bruce Mitchener 527a7fdfbd [libc++] Replace several uses of 0 by nullptr
Differential Revision: https://reviews.llvm.org/D43159
2020-11-27 10:00:21 -05:00
Marek Kurdej 5641b1dfdd [libc++] Mark a few more tests as unsupported on gcc-8/9.
This will fix remaining failures on gcc-9 buildbot: http://lab.llvm.org:8011/#/builders/101.
gcc-8 and gcc-9 do not support constexpr destructors nor constexpr allocation.

Fix gcc warnings: -Wconversion, -Wpragmas.
2020-11-26 12:40:50 +01:00
Marek Kurdej dde0fcd7a7 [libc++] [libc++abi] Mark a few tests as unsupported/xfail on gcc-7/8/9.
This should make the builder http://lab.llvm.org:8011/#/builders/101/ happy.
It uses gcc-9 and not Tip-Of-Trunk as its name indicates BTW.
GCC-10 passes all these tests.

Fix gcc warnings: -Wsign-compare, -Wparentheses, -Wpragmas.

Reviewed By: ldionne, #libc, #libc_abi

Differential Revision: https://reviews.llvm.org/D92099
2020-11-26 08:59:52 +01:00
Louis Dionne a78aaa1ad5 [libc++] Factor out common logic for calling aligned allocation
There were a couple of places where we needed to call the underlying
platform's aligned allocation/deallocation function. Instead of having
the same logic all over the place, extract the logic into a pair of
helper functions __libcpp_aligned_alloc and __libcpp_aligned_free.

The code in libcxxabi/src/fallback_malloc.cpp looks like it could be
simplified after this change -- I purposefully did not simplify it
further to keep this change as straightforward as possible, since it
is touching very important parts of the library.

Also, the changes in libcxx/src/new.cpp and libcxxabi/src/stdlib_new_delete.cpp
are basically the same -- I just kept both source files in sync.

The underlying reason for this refactoring is to make it easier to support
platforms that provide aligned allocation through C11's aligned_alloc
function instead of posix_memalign. After this change, we'll only have
to add support for that in a single place.

Differential Revision: https://reviews.llvm.org/D91379
2020-11-25 15:44:50 -05:00
Marek Kurdej 3b625060fc [libc++] [libc++abi] Use C++20 standard.
This change is needed to use char8_t when building libc++.
Using the same standard in libc++abi for coherence.

See https://reviews.llvm.org/D91517.

Reviewed By: ldionne, #libc, #libc_abi

Differential Revision: https://reviews.llvm.org/D91691
2020-11-22 15:57:25 +01:00
Richard Smith bec968cbb3 Demangling support for class type non-type template parameter extensions.
The extensions in question are described in:
https://github.com/itanium-cxx-abi/cxx-abi/issues/47
https://github.com/itanium-cxx-abi/cxx-abi/issues/63

Differential Revision: https://reviews.llvm.org/D90003
2020-11-20 13:45:08 -08:00