We add `--unwindlib=none` to `CMAKE_REQUIRED_FLAGS`
to make sure that builds with a yet-incomplete toolchain succeed,
to avoid linker failures about missing unwindlib.
When this option is added to `CMAKE_REQUIRED_FLAGS`, it gets added to
both compile and link commands in CMake compile tests. If
`--unwindlib=none` is included in compilation commands, it causes
warnings about unused arguments, as the flag only is relevant for
linking.
Due to the warnings in CMake tests, the later CMake test for the
`-Werror` option failed (as the tested `-Werror` option caused the
preexisting warning due to unused `--unwindlib=none` to become a
hard error). Therefore, most CI configurations that build with
`LIBCXX_ENABLE_WERROR` didn't actually end up enabling `-Werror`
after all.
When looking at the CI build log of recent CI builds, they do
end up printing:
-- Performing Test LIBCXX_SUPPORTS_WERROR_FLAG
-- Performing Test LIBCXX_SUPPORTS_WERROR_FLAG - Failed
-- Performing Test LIBCXX_SUPPORTS_WX_FLAG
-- Performing Test LIBCXX_SUPPORTS_WX_FLAG - Failed
Thus while the configurations are meant to error out on warnings,
they actually haven't done that, due to the interaction of these
options.
To fix this, remove the individual cases of adding `--unwindlib=none`
into `CMAKE_REQUIRED_FLAGS` in libcxx and libunwind.
`runtimes/CMakeLists.txt` still adds `--unwindlib=none` if needed, but
not otherwise. (The same issue with enabling `-Werror` does remain
if `--unwindlib=none` strictly is needed though - that can be fixed
separately afterwards.)
These individual cases in libunwind and libcxx were added while
standalone builds of the runtimes still were supported - but no longer
are necessary now.
Differential Revision: https://reviews.llvm.org/D124375
Avoid repeating CMake checks across runtimes by unifying names of
variables used for results to leverage CMake caching.
Differential Revision: https://reviews.llvm.org/D110005
We previously had a few varied definitions of this floating around.
I had tried to make the one installed with LLVM handle all the cases, and then made the others use it, but this ran into issues with `HandleOutOfTreeLLVM` not working for compiler-rt, and also `CMAKE_EXE_LINKER_FLAGS` not working right without `CMP0056` set to the new behavior.
My compromise solution is this:
- No not completely deduplicate: the runtime libs will instead use a version that still exists as part of the internal and not installed common shared CMake utilities. This avoids `HandleOutOfTreeLLVM` or a workaround for compiler-rt.
- Continue to use `CMAKE_REQUIRED_FLAGS`, which effects compilation and linking. Maybe this is unnecessary, but it's safer to leave that as a future change. Also means we can avoid `CMP0056` for now, to try out later, which is good incrementality too.
- Call it `llvm_check_compiler_linker_flag` since it, in fact is about both per its implementation (before and after this patch), so there is no name collision.
In the future, we might still enable CMP0056 and make compiler-rt work with HandleOutOfTreeLLVM, which case we delete `llvm_check_compiler_flag` and go back to the old way (as these are, in fact, linking related flags), but that I leave for someone else as future work.
The original issue was reported to me in https://reviews.llvm.org/D116521#3248117 as
D116521 made clang and LLVM use the common cmake utils.
Reviewed By: sebastian-ne, phosek, #libunwind, #libc, #libc_abi, ldionne
Differential Revision: https://reviews.llvm.org/D117537
We previously had a few varied definitions of this floating around. I made the one installed with LLVM handle all the cases, and then made the others use it.
This issue was reported to me in https://reviews.llvm.org/D116521#3248117 as
D116521 made clang and llvm use the common cmake utils.
Reviewed By: sebastian-ne, phosek, #libunwind, #libc, #libc_abi, ldionne
Differential Revision: https://reviews.llvm.org/D117537
When building libcxx, libcxxabi, and libunwind the build environment may
specify any number of sanitizers. For some build feature tests these
sanitizers must be disabled to prevent spurious linking errors. With
-fsanitize= this is straight forward with -fno-sanitize=all. With
-fsanitize-coverage= there is no -fno-sanitize-coverage=all, but there
is the equivalent undocumented but tested -fsanitize-coverage=0.
The current build rules fail to disable 'trace-pc-guard'. By disabling
all sanitize-coverage flags, including 'trace-pc-guard', possible
spurious linker errors are prevented. In particular, this allows libcxx,
libcxxabi, and libunwind to be built with HonggFuzz.
CMAKE_REQUIRED_FLAGS is extra compile flags when running CMake build
configuration steps (like check_cxx_compiler_flag). It does not affect
the compile flags for the actual build of the project (unless of course
these flags change whether or not a given source compiles and links or
not). So libcxx, libcxxabi, and libunwind will still be built with any
specified sanitize-coverage as before. The build configuration steps
(which are mostly checking to see if certain compiler flags are
available) will not try to compile and link "int main() { return 0;}"
(or other specified source) with sanitize-coverage (which can fail to
link at this stage in building, since the final compile flags required
are yet to be determined).
The change to LIBFUZZER_CFLAGS was done to keep it consistent with the
obvious intention of disabling all sanitize-coverage. This appears to
be intentional, preventing the fuzzer driver itself from showing up in
any coverage calculations.
Reviewed By: #libunwind, #libc, #libc_abi, ldionne, phosek
Differential Revision: https://reviews.llvm.org/D116050
This does mostly the same as D112126, but for the runtimes cmake files.
Most of that is straightforward, but the interdependency between
libcxx and libunwind is tricky:
Libunwind is built at the same time as libcxx, but libunwind is not
installed yet. LIBCXXABI_USE_LLVM_UNWINDER makes libcxx link directly
against the just-built libunwind, but the compiler implicit -lunwind
isn't found. This patch avoids that by adding --unwindlib=none if
supported, if we are going to link explicitly against a newly built
unwinder anyway.
Since the previous attempt, this no longer uses
llvm_enable_language_nolink (and thus doesn't set
CMAKE_TRY_COMPILE_TARGET_TYPE=STATIC_LIBRARY during the compiler
sanity checks). Setting CMAKE_TRY_COMPILE_TARGET_TYPE=STATIC_LIBRARY
during compiler sanity checks makes cmake not learn about some
aspects of the compiler, which can make further find_library or
find_package fail. This caused OpenMP to not detect libelf and libffi,
disabling some OpenMP target plugins.
Instead, require the caller to set CMAKE_{C,CXX}_COMPILER_WORKS=YES
when building in a configuration with an incomplete toolchain.
Differential Revision: https://reviews.llvm.org/D113253
This reverts commit 317dc31e53.
After that change, OpenMP doesn't find dependencies in the host
system (it fails do find e.g. /usr/lib/x86_64-linux-gnu/libelf.so
which it found before), which causes some OpenMP target offloading
plugins to not be found. This doesn't break the build, but just
causes the AMDGPU OpenMP target plugin to be omitted. See
https://reviews.llvm.org/D113253#3181934 for the report of this
issue.
This does mostly the same as D112126, but for the runtimes cmake files.
Most of that is straightforward, but the interdependency between
libcxx and libunwind is tricky:
Libunwind is built at the same time as libcxx, but libunwind is not
installed yet. LIBCXXABI_USE_LLVM_UNWINDER makes libcxx link directly
against the just-built libunwind, but the compiler implicit -lunwind
isn't found. This patch avoids that by adding --unwindlib=none if
supported, if we are going to link explicitly against a newly built
unwinder anyway.
Reapplying this after
db32c4f456, which should fix the issues
that were reported last time this was applied.
Differential Revision: https://reviews.llvm.org/D113253
This does mostly the same as D112126, but for the runtimes cmake files.
Most of that is straightforward, but the interdependency between
libcxx and libunwind is tricky:
Libunwind is built at the same time as libcxx, but libunwind is not
installed yet. LIBCXXABI_USE_LLVM_UNWINDER makes libcxx link directly
against the just-built libunwind, but the compiler implicit -lunwind
isn't found. This patch avoids that by adding --unwindlib=none if
supported, if we are going to link explicitly against a newly built
unwinder anyway.
Differential Revision: https://reviews.llvm.org/D113253
There's a lot of duplicated calls to find various compiler-rt libraries
from build of runtime libraries like libunwind, libc++, libc++abi and
compiler-rt. The compiler-rt helper module already implemented caching
for results avoid repeated Clang invocations.
This change moves the compiler-rt implementation into a shared location
and reuses it from other runtimes to reduce duplication and speed up
the build.
Differential Revision: https://reviews.llvm.org/D88458
There's a lot of duplicated calls to find various compiler-rt libraries
from build of runtime libraries like libunwind, libc++, libc++abi and
compiler-rt. The compiler-rt helper module already implemented caching
for results avoid repeated Clang invocations.
This change moves the compiler-rt implementation into a shared location
and reuses it from other runtimes to reduce duplication and speed up
the build.
Differential Revision: https://reviews.llvm.org/D88458
When `libcxx` or `libcxxabi` is built with `-DLLVM_USE_SANITIZER=MemoryWithOrigins`
**and** `-DLIBCXX[ABI]_USE_COMPILER_RT=ON`, all of the `LIBCXX[ABI]_SUPPORTS_*_FLAG`
checks fail, since the value of `CMAKE_REQUIRED_FLAGS` is not set correctly.
Bugzilla: https://bugs.llvm.org/show_bug.cgi?id=51774
Reviewed By: #libc, #libc_abi, compnerd, ldionne
Differential Revision: https://reviews.llvm.org/D109342
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
Before this patch, we tried detecting whether small atomics were available
without linking against libatomic. However, that's not really what we want
to know -- instead, we want to know what's required in order to support
atomics fully, which is to link against libatomic when it's provided.
That is both much simpler, and it doesn't suffer the problem that we would
not link against libatomic when small atomics didn't require it, which
lead to non-lockfree atomics never working.
Furthermore, because we understand that some platforms might not want to
(or be able to) ship non-lockfree atomics, we add that notion to the test
suite, independently of a potential extern library.
After this patch, we therefore:
(1) Link against libatomic when it is provided
(2) Independently detect whether non-lockfree atomics are supported in
the test suite, regardless of whether that means we're linking against
an external library or not (which is an implementation detail).
Differential Revision: https://reviews.llvm.org/D81190
Android doesn't have a libgcc_s and uses libgcc instead, so adjust the
build accordingly. This matches compiler-rt's build setup. libc++abi and
libunwind were already checking for libgcc but in a different context.
This change makes them search only for libgcc on Android now, but the
code to link against libgcc if it were present was already there.
Reviewed By: #libc, #libc_abi, #libunwind, rprichard, srhines
Differential Revision: https://reviews.llvm.org/D78787
These are a part of the libc so linking these explicitly isn't necessary
and embedding these as deplibs causes link time error.
This issues was introduced in a9b5fff which changed how we emit deplibs.
Differential Revision: https://reviews.llvm.org/D71135
These seemed to have been used in the past but were since removed
by the add_compile_flags_if_supported functions that combine these
these checks and adding the flag, but the original checks were never
removed.
Differential Revision: https://reviews.llvm.org/D62566
llvm-svn: 362058
This fixes the issue introduced by r362048 where we always use
pragma comment(lib, ...) for dependent libraries when the compiler
is Clang, but older Clang versions don't support this pragma so
we need to check first if it's supported before using it.
llvm-svn: 362055
Instead of manually linking against libm/librt/libpthread, we should be
linking against libSystem on Apple platforms, and only that. libm and
libpthread are symlinks to libSystem anyway.
llvm-svn: 359808
The check_library_exists CMake uses a custom symbol definition. This
is a problem when checking for C library symbols because Clang
recognizes many of them as builtins, and returns the
-Wbuiltin-requires-header (or -Wincompatible-library-redeclaration)
error. When building with -Werror which is the default, this causes
the check_library_exists check fail making the build think that C
library isn't available.
To avoid this issue, we should use a symbol that isn't recognized by
Clang and wouldn't cause the same issue. __libc_start_main seems like
reasonable choice that fits the bill.
Differential Revision: https://reviews.llvm.org/D57142
llvm-svn: 352341
We're using -nodefaultlibs to avoid the dependency on C++ library
when using check_cxx_compiler_flag, and as such we cannot use
check_cxx_compiler_flag to check the availability of -nodefaultlibs
itself.
llvm-svn: 299711
When compiler-rt is requested, we should attempt to link compiler-rt
builtins library rather than gcc_s.
Differential Revision: https://reviews.llvm.org/D31617
llvm-svn: 299599
Summary:
mingw64 has lots of default libs that libc++ and its test programs
should link against.
With this patch, cmake now runs successfully with GCC on Windows.
Reviewers: mati865, EricWF
Subscribers: mgorny, cfe-commits
Differential Revision: https://reviews.llvm.org/D31518
llvm-svn: 299144
Hard code the defaults for Windows for the time being. The checks
really are always going to return the same value. Technically, the
pthread linkage is possible, however, it seems better to use the Win32
threading along with the external threading support that we have added.
llvm-svn: 290801
We're compiling libc++ with -nodefaultlibs, so we should also pass this
option during the configuration checks to ensure those checks are
consistent with the actual build.
The primary motivation here is to ease cross-compilation against a
non-standard set of C++ libraries. Previously, the configuration checks
would attempt to link against the standard C++ libraries, which would
cause link failures when cross-compiling, even though the actual library
link would go through correctly (because of the use of -nodefaultlibs
and explicitly specifying any needed libraries). This is more correct
even ignoring the motivation, however.
Patch by Shoaib Meenai!
llvm-svn: 280015
We're compiling libc++ with -nodefaultlibs, so we should also pass this option
during the configuration checks to ensure those checks are consistent with the
actual build.
The primary motivation here is to ease cross-compilation against a non-standard
set of C++ libraries. Previously, the configuration checks would attempt to link
against the standard C++ libraries, which would cause link failures when
cross-compiling, even though the actual library link would go through correctly
(because of the use of -nodefaultlibs and explicitly specifying any needed
libraries). This is more correct even ignoring the motivation, however.
Patch by Shoaib Meenai!
llvm-svn: 279584
This re-applies commit r260235. However, this time we add -gcc-toolchain
to the compiler's flags when the user has specified the LIBCXX_GCC_TOOLCHAIN
variable.
llvm-svn: 260515
This reverts commit r260235. It breaks LLVM's bootstrap when building
with a -gcc-toolchain and the system's gcc installation does not provide
the libatomic library and its headers. We should check whether
LIBCXX_GCC_TOOLCHAIN is set and adjust the flags accordingly.
llvm-svn: 260323
Summary:
This fixes the tests under std/atomics for 32-bit MIPS CPUs where the
8-byte atomic operations call into the libatomic library.
Reviewers: dsanders, mclow.lists, EricWF, jroelofs, joerg
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D16613
llvm-svn: 260235
Summary:
This patch adds Sphinx based documentation to libc++. The goal is to make it easier to write documentation for libc++ since writing new documentation in HTML is cumbersome. This patch rewrites the main page for libc++ along with the instructions for using, building and testing libc++.
The built documentation can be found and reviewed here: http://efcs.ca/libcxx-docs
In order to build the sphinx documentation you need to specify the cmake options `-DLLVM_ENABLE_SPHINX=ON -DLIBCXX_INCLUDE_DOCS=ON`. This will add the makefile rule `docs-libcxx-html`.
Reviewers: chandlerc, mclow.lists, danalbert, jroelofs
Subscribers: silvas, cfe-commits
Differential Revision: http://reviews.llvm.org/D12129
llvm-svn: 245788
This patch adds the working parts of r243503. The difference with this patch
is that it doesn't include the HandleLLVMOptions.cmake file.
llvm-svn: 243698
This change was reverted in r243550 because it broke clang-format builds
(see PR24306).
This patch recommits a fixed version of the original.
llvm-svn: 243574
Summary:
This patch contains the following changes:
1. Require that libc++ can find a LLVM source directory. This is done the same way as `libc++abi` currently does.
2. Cleanup ugly configuration code in CMakeLists.txt by using `add_flags`, `add_flags_if`, and `add_flags_if_supported` macros.
The goals for this patch are:
1. Help libc++ be more consistent with how LLVM handles CMake options (see PR23670 PR23671).
2. Make it easier to use sanitizers using the `LLVM_USE_SANITIZER` option.
3. Make libc++'s CMakeLists.txt file easier to understand and change.
4. Move towards allowing libc++ to create Sphinx documentation (see http://efcs.ca/libcxx-docs).
5. Move towards allowing libc++ to use other LLVM utilities such as `not` and `FileCheck`.
Reviewers: mclow.lists, jroelofs, danalbert
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D11308
llvm-svn: 243503
Summary:
This patch adds support for LLVM_USE_SANITIZER when being built in-tree and standalone.
This patch does the following things:
1. define the LLVM_USE_SANITIZER option to "" when being built standalone. This also helps show we support it.
2. Translate LLVM_USE_SANITIZER when standalone in a very similar way done in llvm/cmake/HandleLLVMOptions.cmake.
3. Add config.llvm_use_sanitizer to lit.site.cfg.in
4. Add code to translate config.llvm_use_sanitizer's value into the needed compile flags in lit.cfg.
Currently lit.cfg assumes that that the compiler supports '-fno-omit-frame-pointer' while CMakeLists.txt actually checks to see if its supported. We could pass this information to lit but I'm not sure its needed.
Reviewers: mclow.lists, danalbert
Reviewed By: danalbert
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D4949
llvm-svn: 215872
Summary:
This patch does two things:
CMake Update:
- Add compiler flag checks for -std=c++11 and -std=c++1y and remove check for -std=c++0x.
- Add configuration option LIBCXX_ENABLE_CXX1Y to prevent/allow -std=c++1y from being chosen as the std version. LIBCXX_ENABLE_CXX1Y is set to OFF by default.
- if LIBCXX_ENABLE_CXX1Y is enabled then set LIBCXX_STD_VERSION to c++1y and fail if the compiler does not support -std=c++1y
- If c++1y is not enabled then use c++11 and fail if the compiler does not support c++11.
Lit Update:
- Update lit.site.cfg.in to capture LIBCXX_STD_VERSION information as config.std.
- Remove mentions of has_cxx0X configuration option.
- Check for `--param std=X' passed to lit on the command line.
- Choose the std for the tests either from command line parameter or (if it doesn't exist) the lit.site.cfg.
Reviewers: mclow.lists, danalbert
Reviewed By: danalbert
Subscribers: emaste, rnk, ajwong, danalbert, cfe-commits
Differential Revision: http://reviews.llvm.org/D4329
llvm-svn: 215802
Martin Storsjö