This commit contains refactorings around __dynamic_cast without changing
its behavior. Some important changes include:
- Refactor __dynamic_cast into various small helper functions;
- Move dynamic_cast_stress.pass.cpp to libcxx/benchmarks and refactor
it into a benchmark. The benchmark performance numbers are updated
as well.
Differential Revision: https://reviews.llvm.org/D138006
Inside the Itanium demangler, we would previously call std::terminate()
after failing to (re)allocate. However, programs are free to install a
custom terminate_handler which does non-trivial things. In fact, by
default libc++abi itself installs a demangling_terminate_handler() which
tries to demangle the currently active exception before aborting the
program.
In case of an out-of-memory exception caused by the system truly having
no more memory (as opposed to attempting to allocate INT_MAX just once),
we will end up trying to demangle the exception, failing to do so because
we can't grow the OutputBuffer inside ItaniumDemangle.h, and then calling
std::terminate() there. That will call the demangling_terminate_handler(),
which will then start this loop again. We eventually end up crashing due
to a stack overflow.
To fix this problem, this patch calls std::abort() directly from the
demangler instead of going through std::terminate(). After all, calling
std::abort() is the default behavior for std::terminate() according
to the Standard, so this behavior is definitely valid. The downside of
this approach is that in case of a "true" out-of-memory condition:
1. the program will throw an exception
2. std::terminate() will be called if uncaught
3. demangling_terminate_handler() will be called and will fail
4. abort() will be called
We'll end up aborting the program without mentioning the cause, which
normally looks like:
terminating due to uncaught exception of type <TYPE>: <what()-MESSAGE>
Another option would be to properly handle failure-to-allocate inside
ItaniumDemangle.h and to propagate something like an error code or a
std::expected to the caller of all functions in the demangler that
can allocate. Then, we could make sure that __cxa_demangle returns
nullptr when it fails to demangle the input due to any error, as it is
supposed to (but today "true" out-of-memory conditions are not handled
properly). The demangling_terminate_handler() would then see that
__cxa_demangle failed to do its job and would still print the
appropriate message, simply using the non-demangled exception type.
However, this is akin to a partial rewrite of the demangler code since
a large number of functions would now have to return a std::expected
to account for out-of-memory conditions.
Using exceptions would be a lot simpler in terms of code changes and
would achieve the same result, however the demangler can't use exceptions
because it is used inside LLVM and libc++abi implements the exception
runtime anyway (so while it might be possible to use them in that
context, I'd argue we'd only be playing with fire).
rdar://110767664
Differential Revision: https://reviews.llvm.org/D155598
If we attempt to use unwind_shared when LIBUNWIND_ENABLE_SHARED is OFF,
we'll get link errors. LIBCXXABI_STATICALLY_LINK_UNWINDER_IN_SHARED_LIBRARY
avoids that, but it seems redundant to have to specify it manually.
Automatically switch libunwind statically when its shared build is
disabled, which also matches compiler-rt [1].
[1] 71bfec762b/compiler-rt/CMakeLists.txt (L238-L240)
Reviewed By: #libc_abi, phosek
Differential Revision: https://reviews.llvm.org/D158789
This patch fixes a few CMake options that were set using incorrect
mechanisms.
CMake's man page for the -D <var>=<value> option states: If a command in
the project sets the type to PATH or FILEPATH, then the <value> will be
converted to an absolute path. That's not what we want for most of the
paths we have as configuration options. Otherwise, using -D to set the
configuration option results in an absolute path being used, which
breaks things.
option() denotes a boolean variable, but what was desired was a
string/list variable. Fix this to prevent cmake from changing any
non-empty user provided values to 'ON'.
Differential Revision: https://reviews.llvm.org/D157926
Our threading support layer is currently a huge mess. There are too many
configurations with too many confusing names, and none of them are tested
in the usual CI. Here's a list of names related to these configurations:
LIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY
_LIBCPP_BUILDING_THREAD_LIBRARY_EXTERNAL
LIBCXXABI_BUILD_EXTERNAL_THREAD_LIBRARY
_LIBCPP_HAS_THREAD_LIBRARY_EXTERNAL
LIBCXX_HAS_EXTERNAL_THREAD_API
_LIBCPP_HAS_THREAD_API_EXTERNAL
This patch cleans this up by removing the ability to build libc++ with
an "external" threading library for testing purposes, removing 4 out of
6 "names" above. That setting was meant to be used by libc++ developers,
but we don't use it in-tree and it's not part of our CI.
I know the ability to use an external threading API is used by some folks
out-of-tree, and this patch doesn't change that. This only changes the
way they will have to test their external threading support. After this
patch, the intent would be for them to set `-DLIBCXX_HAS_EXTERNAL_THREAD_API=ON`
when building the library, and to provide their usual `<__external_threading>`
header when they are testing the library. This can be done easily now
that we support custom lit configuration files in test suites.
The motivation for this patch is that our threading support layer is
basically unmaintainable -- anything beyond adding a new "backend" in
the slot designed for it requires incredible attention. The complexity
added by this setting just doesn't pull its weigh considering the
available alternatives.
Concretely, this will also allow future patches to clean up
`<__threading_support>` significantly.
Differential Revision: https://reviews.llvm.org/D154466
To fix expensive check builds that were failing when using MSVC's
std::string_view::iterator::operator*, I added a few expressions like
&*std::string_view::begin. @nico pointed out that this is literally the
same thing and more clearly expressed as std::string_view::data.
Link: https://github.com/llvm/llvm-project/issues/63740
Reviewed By: #libc_abi, ldionne, philnik, MaskRay
Differential Revision: https://reviews.llvm.org/D154876
This allows mechanically copying any changes made to `operator new`
from libc++ into libc++abi as-is. This is also a step towards
de-duplicating this code entirely.
Differential Revision: https://reviews.llvm.org/D153035
That is not necessary to test what we're testing, and in fact including
abort_message.cpp into that file caused some link errors if we didn't
link some of the dependencies of libc++abi directly into the test.
Differential Revision: https://reviews.llvm.org/D152862
Now that we've converted libcxxabi and llvm Demangle to use
std::string_view, this code no longer has any users. Bye bye!
Reviewed By: #libc_abi, phosek, MaskRay
Differential Revision: https://reviews.llvm.org/D148387
I made a series of changes to LLVM's demangle in:
- D148348
- D148353
- D148363
- D148375
and so did Fangrui in 3ece37b3fa2c and Ashay in D149061.
I didn't notice the banner about there being two copies of this in tree
and was modifying the downstream versions. Copy these changes back to
the upstream version. Oops!
Reviewed By: MaskRay, #libc_abi, ldionne, phosek
Differential Revision: https://reviews.llvm.org/D148566
This reverts commit d763c6e5e2d0a6b34097aa7dabca31e9aff9b0b6.
Adds the patch by @hans from
https://github.com/llvm/llvm-project/issues/62719
This patch fixes the Windows build.
d763c6e5e2d0a6b34097aa7dabca31e9aff9b0b6 reverted the reviews
D144509 [CMake] Bumps minimum version to 3.20.0.
This partly undoes D137724.
This change has been discussed on discourse
https://discourse.llvm.org/t/rfc-upgrading-llvms-minimum-required-cmake-version/66193
Note this does not remove work-arounds for older CMake versions, that
will be done in followup patches.
D150532 [OpenMP] Compile assembly files as ASM, not C
Since CMake 3.20, CMake explicitly passes "-x c" (or equivalent)
when compiling a file which has been set as having the language
C. This behaviour change only takes place if "cmake_minimum_required"
is set to 3.20 or newer, or if the policy CMP0119 is set to new.
Attempting to compile assembly files with "-x c" fails, however
this is workarounded in many cases, as OpenMP overrides this with
"-x assembler-with-cpp", however this is only added for non-Windows
targets.
Thus, after increasing cmake_minimum_required to 3.20, this breaks
compiling the GNU assembly for Windows targets; the GNU assembly is
used for ARM and AArch64 Windows targets when building with Clang.
This patch unbreaks that.
D150688 [cmake] Set CMP0091 to fix Windows builds after the cmake_minimum_required bump
The build uses other mechanism to select the runtime.
Fixes#62719
Reviewed By: #libc, Mordante
Differential Revision: https://reviews.llvm.org/D151344
In D148959, I removed usage of std::string_view::substr because it may
throw, and libcxxabi cannot use such code. I missed one instance in
llvm::starts_with. That is blocking copying the code back upstream in
D148566.
Mark these helpers noexcept (as they are in C++20) as well, to remind
future travelers.
Make these changes upstream, and copy them back downstream using
libcxxabi/src/demangle/cp-to-llvm.sh.
Reviewed By: #libc_abi, MaskRay, ldionne
Differential Revision: https://reviews.llvm.org/D151260
unittest_demangle.pass.cpp uses the preprocessor to #include
cxa_demangle.cpp. D148566 will make more use of std::string_view in
libcxxabi rather than the home-grown StringView, but as a result of
D149092, a definition of abort_message needs to be provided.
Otherwise builds of check-cxxabi with -DLLVM_ENABLE_ASSERTIONS=ON will
fail to link with the errors:
/usr/bin/ld: /tmp/lit-tmp-0akcq37p/cc6DLdvw.o: in function `(anonymous namespace)::itanium_demangle::starts_with(std::__1::basic_string_view<char, std::__1::char_traits<char> >, char)':
unittest_demangle.pass.cpp:(.text+0x81): undefined reference to `abort_message'
/usr/bin/ld: /tmp/lit-tmp-0akcq37p/cc6DLdvw.o: in function `(anonymous namespace)::itanium_demangle::starts_with(std::__1::basic_string_view<char, std::__1::char_traits<char> >, std::__1::basic_string_view<char, std::__1::char_traits<char> >)':
unittest_demangle.pass.cpp:(.text+0x2aa): undefined reference to `abort_message'
/usr/bin/ld: unittest_demangle.pass.cpp:(.text+0x312): undefined reference to `abort_message'
/usr/bin/ld: /tmp/lit-tmp-0akcq37p/cc6DLdvw.o: in function `(anonymous namespace)::itanium_demangle::OutputBuffer::writeUnsigned(unsigned long, bool)':
unittest_demangle.pass.cpp:(.text+0x54f): undefined reference to `abort_message'
/usr/bin/ld: unittest_demangle.pass.cpp:(.text+0x5b7): undefined reference to `abort_message'
/usr/bin/ld: /tmp/lit-tmp-0akcq37p/cc6DLdvw.o:unittest_demangle.pass.cpp:(.text+0xe6e): more undefined references to `abort_message' follow
/usr/bin/ld: /home/libcxx-builder/.buildkite-agent/builds/google-libcxx-builder-f0560ea595b1-1/llvm-project/libcxx-ci/build/generic-gcc/test/Output/unittest_demangle.pass.cpp.dir/t.tmp.exe: hidden symbol `abort_message' isn't defined
Use the preprocessor further to provide the definition of abort_message
for this unittest.
Reviewed By: #libc_abi, phosek
Differential Revision: https://reviews.llvm.org/D151160
This is an ongoing series of commits that are reformatting our
Python code.
Reformatting is done with `black`.
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.
If you run into any problems, post to discourse about it and
we will try to help.
RFC Thread below:
https://discourse.llvm.org/t/rfc-document-and-standardize-python-code-style
Reviewed By: #libc, kwk, Mordante
Differential Revision: https://reviews.llvm.org/D150763
@asbirlea reports that Google does this for sanitizer analysis
downstream. Looks like a few #defines are added into a header which is
then injected into the build.
Reviewed By: vitalybuka, ldionne, #libc_abi
Differential Revision: https://reviews.llvm.org/D150825
libc++ may be built with or without assertions. This causes definitions
of various methods of std::string_view to contain assertions and calls
to __libcpp_verbose_abort which libcxxabi does not provide. libcxxabi
does provide abort_message with the same interface, so define
_LIBCPP_VERBOSE_ABORT to use that. Otherwise D148566 will trigger
linkage failures for the missing symbol __libcpp_verbose_abort.
Link: https://libcxx.llvm.org/UsingLibcxx.html#enabling-the-safe-libc-mode
Reviewed By: #libc_abi, philnik, ldionne
Differential Revision: https://reviews.llvm.org/D149092
This reverts commit 65429b9af6a2c99d340ab2dcddd41dab201f399c.
Broke several projects, see https://reviews.llvm.org/D144509#4347562 onwards.
Also reverts follow-up commit "[OpenMP] Compile assembly files as ASM, not C"
This reverts commit 4072c8aee4c89c4457f4f30d01dc9bb4dfa52559.
Also reverts fix attempt "[cmake] Set CMP0091 to fix Windows builds after the cmake_minimum_required bump"
This reverts commit 7d47dac5f828efd1d378ba44a97559114f00fb64.
On Windows, the PATH env variable is used for locating dynamically
linked librarys, akin to LD_LIBRARY_PATH on Linux.
The tests that run with a dynamically linked libc++ used "--env
PATH=%{lib}" in the test config. This had the unfortunate side effect
of making other tools from PATH unavailable during the runtime of the
tests; in particular, it caused the "executor-has-no-bash" flag to be
set for all those Windows test configs (with the clang-cl static config
being the only one lacking it).
Thus, this increases the number of tests actually included in the
clang-cl dll and all mingw test configs by 9 tests.
The clang-cl static test configuration has been executing those tests
since the "--env PATH=%{lib}" was removed from that test config in
e78223e79efc886ef6f0ea5413deab3737d6d63b. (For mingw we haven't had a
need to split the test config between shared and static, which means
that the mingw static test config previously ran with --env PATH
needlessly.)
This increases the test coverage for patches like D146398 which
can't be executed in the executor-has-no-bash configs.
Change the default value of the arg.env to an empty array; when we do
pass values to the option, they get passed as an array of strings,
so make sure the variable behaves consistently when no arguments
have been passed.
Differential Revision: https://reviews.llvm.org/D148324
On z/OS, we need to pass the location of unwind interface header when building cxxabi. The cmake macro `LIBCXXABI_LIBUNWIND_INCLUDES_INTERNAL` is available for this purpose but it is only used with conjunction with `LIBCXXABI_USE_LLVM_UNWINDER`. For the external unwind library we need to use LIBCXXABI_LIBUNWIND_INCLUDES_INTERNAL unconditionally whenever it is set.
Reviewed By: #libc_abi, muiez, phosek, SeanP
Differential Revision: https://reviews.llvm.org/D147460
We decided to go a different route. To make the switch easier, rip out the old integration first and build on a clean base.
Reviewed By: ldionne, #libc, #libc_abi
Spies: arichardson, libcxx-commits
Differential Revision: https://reviews.llvm.org/D148480
Add C++ 20 style starts_with to replace StringView::startsWith in
LLVMDemangle. Due to library layering (LLVMSupport depends on
LLVMDemangle), we add the utility header under llvm/Demangle, instead of
llvm/ADT or llvm/Support.
Modify this in libcxxabi, then copy this over to llvm.
Reviewed By: MaskRay, #libc_abi, phosek
Differential Revision: https://reviews.llvm.org/D148556
The new message is a bit verbose, but it makes it clearer that this isn't
a problem in libc++abi, but instead a problem in the user's code. Otherwise,
we get bugs sent down to libc++abi because people see this message in their
crash logs.
Differential Revision: https://reviews.llvm.org/D148630
Don't link libc++abi separately in addition to the main -lc++; in
mingw build configs, libc++abi is always bundled into libc++
(via LIBCXX_ENABLE_STATIC_ABI_LIBRARY).
In the case of a shared linked libc++, linking a separate static
libc++abi leads to linker errors.
Differential Revision: https://reviews.llvm.org/D147638
With current versions of mingw-w64 headers, code following
assert(false) isn't considered unreachable - thus add a dummy
"return nullptr;", to avoid warnings (treated as errors) for a
missing return statement.
The root cause does get fixed further upstream in mingw-w64 in
1690994f51
though.
Differential Revision: https://reviews.llvm.org/D147860
This matches the corresponding change to libcxx headers in
dfa88927ae1411ccc3b248b7e624f2acf623d947.
This avoids needing to define _LIBCXXABI_DISABLE_VISIBILITY_ANNOTATIONS
when building libcxxabi tests, for two reasons:
- It defaults to normal linkage (as opposed to dllimport), fixing
linking of a static library version of libcxx/libcxxabi
- It avoids issues with using dllimport declarations on symbols when
including cxxabi implementations into the testcase itself
Differential Revision: https://reviews.llvm.org/D148441
Previously, all the output from the tests were placed directly in
the build directory. The tests produce a couple directories named
`__config_{exec,cache,src}__` which are easy to distinguish, and
the output from the individual tests were placed directly in a
directory named `Output`.
This is the same change as
736c6e246f5398331d83edd204a846cc967ad5c6, but for the libcxxabi
and libunwind test suites.
Differential Revision: https://reviews.llvm.org/D147628
With current versions of mingw-w64, TLS destructors that are registered
while executing TLS destructors are lost and leaked.
The root cause does get fixed further upstream in mingw-w64 in
71eddccd74
though, but mark the test as unsupported for now. The marking can be
removed later when the version used in the CI runner has been updated
to include the fix.
Differential Revision: https://reviews.llvm.org/D147859
This is the same as c218c80c730a14a1cbcebd588b18220a879702c6,
but for libcxxabi and libunwind.
This fixes running tests on Windows with Python installed in
e.g. "C:\Program Files\Python38".
Differential Revision: https://reviews.llvm.org/D147629
The use_system_cxx_lib Lit feature was only used for back-deployment
testing. However, one immense hole in that setup was that we didn't
have a proper way to test Apple's own libc++ outside of back-deployment,
which was embodied by the fact that we needed to define _LIBCPP_DISABLE_AVAILABILITY
when testing (see change in libcxx/utils/libcxx/test/params.py).
This led to the apple-system testing configuration not checking for
availability markup, which is obviously quite bad since the library
we ship actually has availability markup.
Using stdlib=<VENDOR>-libc++ instead to encode back-deployment restrictions
on tests is simpler and it makes it possible to naturally support tests
such as availability markup checking even in the tip-of-trunk Apple-libc++
configuration.
Differential Revision: https://reviews.llvm.org/D146366
Before this patch we would demangle abi-tagged structures as follows:
```
$ c++filt -n _ZN1SB5OuterC2Ev
S[abi:Outer]:()
$ c++filt -n _ZN1SB5OuterD2Ev
S[abi:Outer]::~()
```
This is because `Node::getBaseName` was unimplemented for the
`AbiTagAttr` node, which meant that when we tried printing `CtorDtorName`
where its `Basename` `Node` was an `AbiTagAttr`, we'd drop the
name.
Addresses https://github.com/llvm/llvm-project/issues/61213
Differential Revision: https://reviews.llvm.org/D145492
The original `__dynamic_cast` implementation does not use the ABI-provided `src2dst_offset` parameter which helps improve performance on the hot paths. This patch improves the performance on the hot paths in `__dynamic_cast` by leveraging hints provided by the `src2dst_offset` parameter. This patch also includes a performance benchmark suite for the `__dynamic_cast` implementation.
Reviewed By: philnik, ldionne, #libc, #libc_abi, avogelsgesang
Spies: mikhail.ramalho, avogelsgesang, xingxue, libcxx-commits
Differential Revision: https://reviews.llvm.org/D138005
This mostly keeps the same warning flags. The most important exceptions are `-Wpedantic` and `-Wconversion`, which are now removed from libc++abi and libunwind.
Reviewed By: ldionne, #libunwind, #libc, #libc_abi
Spies: mikhail.ramalho, phosek, libcxx-commits
Differential Revision: https://reviews.llvm.org/D144252
