In a `-DCMAKE_BUILD_TYPE=Release -DLLVM_TARGETS_TO_BUILD=X86 -DLLVM_LINK_LLVM_DYLIB=on -DCLANG_LINK_CLANG_DYLIB=on`
build, libLLVM-13git.so is 2% smaller and libclang-cpp.so is 1% smaller (on top of -Wl,-Bsymbolic-functions).
There may be some small performance improvement as well because GCC
-fPIC suppresses interprocedural optimizations for non-inline
definitions by default.
Note: we cannot add -fno-semantic-interposition for Clang<13. Clang<13's
implementation additionally optimizes global variables, which is incompatible
with unfortunate ELF -fno-pic default: direct access relocations for external
data. If the executable has a -fno-pic object file referencing a global variable
declared in a public header, the direct access relocation will cause a copy
relocation. The executable and libLLVM.so/libclang-cpp.so will disagree on the
address.
Reviewed By: phosek
Differential Revision: https://reviews.llvm.org/D102453
This precomputes some hashes that LLD uses for type merging to speed up
linking when PDBs are enabled. Only do this if any kind of /DEBUG flag
is passed to the linker. -gcodeview-ghash is orthogonal to /Z7, -g, -g1,
or -gmlt, so it is safe to set it independently from those flags. It
will not increase debug info emission.
Differential Revision: https://reviews.llvm.org/D103287
lld/MachO/Driver.cpp and lld/MachO/SyntheticSections.cpp include
llvm/Config/config.h which doesn't exist when building standalone lld.
This patch replaces llvm/Config/config.h include with llvm/Config/llvm-config.h
just like it is in lld/ELF/Driver.cpp and HAVE_LIBXAR with LLVM_HAVE_LIXAR and
moves LLVM_HAVE_LIBXAR from config.h to llvm-config.h
Also it adds LLVM_HAVE_LIBXAR to LLVMConfig.cmake and links liblldMachO2.so
with XAR_LIB if LLVM_HAVE_LIBXAR is set.
Differential Revision: https://reviews.llvm.org/D102084
We already use -O0 for unittests under ThinLTO, do the same for full LTO
where the compile time costs to runtime benefits tradeoff is even worse.
Differential Revision: https://reviews.llvm.org/D102718
It's easy to hit 2**16 limit with i686 GNU toolchains these days.
Clang does it automagically, so it's not needed there, and the option
causes warnings about being unused when linking.
Differential Revision: https://reviews.llvm.org/D102419
LLVM's build system contains support for configuring a distribution, but
it can often be useful to be able to configure multiple distributions
(e.g. if you want separate distributions for the tools and the
libraries). Add this support to the build system, along with
documentation and usage examples.
Reviewed By: phosek
Differential Revision: https://reviews.llvm.org/D89177
llvm-dev message: https://lists.llvm.org/pipermail/llvm-dev/2021-May/150465.html
In an ELF shared object, a default visibility defined symbol is preemptible by default.
This creates some missed optimization opportunities. -fno-semantic-interposition can optimize -fPIC:
* in Clang: avoid GOT/PLT cost for variable access/function calls to external linkage definition in the same TU
* in GCC: enable interprocedural optimizations (including inlining) and avoid PLT
See https://gist.github.com/MaskRay/2d4dfcfc897341163f734afb59f689c6 for more information.
-Bsymbolic-functions is more aggressive than -fvisibility-inlines-hidden (present since 2012) as it applies
to all function definitions. It can
* avoid PLT for cross-TU function calls && reduce dynamic symbol lookup
* reduce dynamic symbol lookup for taking function addresses and optimize out GOT/TOC on x86-64/ppc64
With both options, the libLLVM.so and libclang-cpp.so performance should
be closer to PIE binary linking against `libLLVM*.a` and `libclang*.a`
(In a -DLLVM_TARGETS_TO_BUILD=X86 build, the number of JUMP_SLOT decreases from 12716 to 1628, and the number of GLOB_DAT decreases from 1918 to 1313
The built clang with `-DLLVM_LINK_LLVM_DYLIB=on -DCLANG_LINK_CLANG_DYLIB=on` is significantly faster.
See the Linux kernel build result https://bugs.archlinux.org/task/70697
)
Some implication:
Interposing a subset of functions is no longer supported.
(This is fragile anyway and cannot really be supported. For Mach-O we don't use
`ld -interpose`, so interposition is not supported on Mach-O at all.)
Compiling a program which takes the address of any LLVM function with
`{gcc,clang} -fno-pic` and expects the address to equal to the address taken
from libLLVM.so or libclang-cpp.so is unsupported. I am fairly confident that
llvm-project shouldn't have different behaviors depending on such pointer
equality (as we've been using -fvisibility-inlines-hidden which applies to
inline functions for a long time), but if we accidentally do, users should be
aware that they should not make assumption on pointer equality in `-fno-pic`
mode.
Reviewed By: phosek
Differential Revision: https://reviews.llvm.org/D102090
If compiling with GCC or linking with ld.bfd, these options have little
effect, but if built with Clang and linked with LLD, they provide a
quite notable size decrease - this shrinks an entire llvm-mingw
distribution package by 22%.
If building with BUILD_SHARED_LIBS or LLVM_BUILD_LLVM_DYLIB with LLD,
this requires a version of LLD that contains a fix for auto exporting
symbols from comdats, 2b01a417d7ccb001ccc1185ef5fdc967c9fac8d7.
Differential Revision: https://reviews.llvm.org/D101568
Match the API for the new check_linker_flag and use it directly when
available, leaving the old code as a fallback.
Differential Revision: https://reviews.llvm.org/D100901
Changing global flags can break builds of projects that include/build
llvm as a sub-project, as the effect is global. Ideally we would
disable this warning at the directory level instead, but the obvious
way (disabling warning D9025) isn't supported. At least we can limit
the effect to only MSVC.
Patch by Jim Radford.
Differential Revision: https://reviews.llvm.org/D100900
This allows one to cross-compile the header/object for a model in a
setup where the compiler is built on a system that cannot host the AOT
compiler. For example, if arm-hostable clang is desired, while the AOT
Tensorflow compiler can cross-compile to arm, it can't currently run on
arm.
The only alternative in that scenario would be to cross-compile clang
itself, but that gets complicated when trying to run tests after that.
Differential Revision: https://reviews.llvm.org/D99992
This makes it possible to build libLLVM.so without first creating a
static library for each component. In the case where only libLLVM.so is
built (i.e. ninja LLVM) this eliminates 150 linker jobs.
Reviewed By: stellaraccident
Differential Revision: https://reviews.llvm.org/D95727
Use the CMake 3.13 features of CMakeConfigPackageHelpers to generate
LLVMConfigVersion.cmake with proper architecture detection, major+minor
version matching, etc.
Differential Revision: https://reviews.llvm.org/D99451
Call `get_errc_messages` only if `LLVM_INCLUDE_TESTS` was set.
Reviewed By: zero9178, abhina.sreeskantharajan, jhenderson
Differential Revision: https://reviews.llvm.org/D98861
Similar to the existing code for disabling GCC's -Wredudant-move,
also check for the -Wpessimizing-move option and disable it if
possible.
This silences another bunch of noisy warnings when building LLVM
with GCC 9.
As noted for -Wredundant-move, the code can't be fixed to silence the
warnings while retaining support for older compilers.
Differential Revision: https://reviews.llvm.org/D98942
BUILD_SHARED_LIBS build llvm component as shared library,
which can reduce the size a lot.
Normally, the binary use ORIGIN../lib to load component libraries,
unfortunatly, ORIGIN is not supported by AIX ld.
We hardcoded the build lib and install lib path in rpath for now
to enable BUILD_SHARED_LIBS build.
Understand that this is not perfect solution,
we can update this when we find better solution.
Reviewed By: hubert.reinterpretcast
Differential Revision: https://reviews.llvm.org/D98901
This matches what GCC warns about when -pedantic is enabled.
This should avoid such redundant semicolons creeping into the codebase.
Differential Revision: https://reviews.llvm.org/D98941
The current cmake script attempts to add the path containing clangs various runtime systems by getting the resource directory and then appending the hardcoded value /lib/windows to it. This works for a normal clang-cl build but fails for a build of clang using LLVM_ENABLE_PER_TARGET_RUNTIME_DIR, such as the builds from llvm/runtimes.
This patch instead uses -print-libgcc-file-name in conjunction with --rtlib=compiler-rt, and instead adds the containing directory as library path.
For non per-target runtime directory builds, such as the release builds, there is no change. Even if the builtins library were to be deleted or moved it would output the same path as before.
For per-target runtime builds that also have the builtins library, this now finds the correct directory containing all of clang runtime libraries.
Only case still not handled by this change, is if a per-target runtime directory build is used, but the builtins library was not built.
I believe that is the best we can do for now however, without modifying clang.
Differential Revision: https://reviews.llvm.org/D98786
If for some reason the test program does not exit normally it'd currently lead to a false positive and it's stdout output being assigned to the output variable.
Instead, check the test program exited normally before assigning the process output to the out variable.
Follow up on rGaf2796c76d2ff4b73165ed47959afd35a769beee
Fixes an issue discovered post commit in https://reviews.llvm.org/D98278
Visual Studios implementation of the C++ Standard Library does not use strerror to produce a message for std::error_code unlike other standard libraries such as libstdc++ or libc++ that might be used.
This patch adds a cmake script that through running a C++ program gets the error messages for the POSIX error codes and passes them onto lit through an optional config parameter.
If the config parameter is not set, or getting the messages failed, due to say a cross compiling configuration without an emulator, it will fall back to using pythons strerror functions.
Differential Revision: https://reviews.llvm.org/D98278
The lit test suite uses python 3.6 features. Rather than a strange
python syntax error upon running the lit tests, we will require the
correct version in CMake.
Reviewed By: serge-sans-paille, yln
Differential Revision: https://reviews.llvm.org/D95635
This allows sending requests through CLI and more debugging
opportunities. Example:
```bash
$ grpc_cli ls localhost:50051
clang.clangd.remote.v1.SymbolIndex
grpc.reflection.v1alpha.ServerReflection
grpc.health.v1.Health
```
Turn `-Wreturn-type` into an error.
This is currently used by libcxx, libcxxabi, and libunwind, and would be a good default
for all of llvm. I'm not aware of any cases where this shouldn't be an error. This
ensures different build configs, merges, and downstream branches catch issues sooner.
Differential Revision: https://reviews.llvm.org/D98224
It moved the logic for CMake target arguments into llvm_ExternalProject_Add().
No handling was added for CMAKE_CROSSCOMPILING, which has a separate set of compiler_args.
This broke crosscompiling, as now the runtimes builds defaulted to the compiler's default.
I've also added passing of CMAKE_ASM_COMPILER, which was missing before although we were passing the triple for it.
Reviewed By: zero9178
Differential Revision: https://reviews.llvm.org/D97855
As stated in the CMake manual, we are supposed to use MODULE rules to generate
plugin libraries:
"MODULE libraries are plugins that are not linked into other targets but may be
loaded dynamically at runtime using dlopen-like functionality"
Besides, LLVM's plugin infrastructure fits with the AIX treatment of .so
shared objects more than it fits with the AIX treatment of .a library archives
(which may contain shared objects).
Differential revision: https://reviews.llvm.org/D96282
Windows is in the unique position of having two drivers, clang-cl and normal GNU clang, depending on whether a GNU or MSVC target is used. The current implementation with the USE_TOOLCHAIN argument assumes that when CMAKE_SYSTEM_NAME is set to Windows that clang-cl should be used, which is the incorrect choice when targeting a GNU environment.
This patch solves this problem by adding an optional TARGET_TRIPLE argument to llvm_ExternalProject_Add, which sets the various CMAKE_<LANG>_COMPILER_TARGET variables. Additionally, if the triple is detected as an MSVC environment, clang-cl and similar MSVC specific tools will be used instead of the GNU tools.
This drops check-llvm under -DLLVM_ENABLE_LTO=Thin from 13m to 10m20s on Windows and 20m to 15m35s on Linux.
Reviewed By: hans
Differential Revision: https://reviews.llvm.org/D96618
As suggested by Nico in https://reviews.llvm.org/D96049, move check for libproc
from CMakeLists to config-ix.cmake
Reviewed By: thakis
Differential Revision: https://reviews.llvm.org/D96713
Note: Also removes the CMAKE_REQUIRED_LIBRARIES which doesn't appear to
be necessary.
Also add a script for sysroot management. For now, it can only create
fake sysroots that just symlink to local folders. This is useful for
testing.
Differential Revision: https://reviews.llvm.org/D96868
Multi-configuration generators (such as Visual Studio and Xcode) allow the specification of a build flavor at build time instead of config time, so the lit configuration files need to support that - and they do for the most part. There are several places that had one of two issues (or both!):
1) Paths had %(build_mode)s set up, but then not configured, resulting in values that would not work correctly e.g. D:/llvm-build/%(build_mode)s/bin/dsymutil.exe
2) Paths did not have %(build_mode)s set up, but instead contained $(Configuration) (which is the value for Visual Studio at configuration time, for Xcode they would have had the equivalent) e.g. "D:/llvm-build/$(Configuration)/lib".
This seems to indicate that we still have a lot of fragility in the configurations, but also that a number of these paths are never used (at least on Windows) since the errors appear to have been there a while.
This patch fixes the configurations and it has been tested with Ninja and Visual Studio to generate the correct paths. We should consider removing some of these settings altogether.
Reviewed By: JDevlieghere, mehdi_amini
Differential Revision: https://reviews.llvm.org/D96427
glibc deprecates `mallinfo` in the latest version of 2.33. This patch replaces the usage of `mallinfo` with the new `mallinfo2` when it's available.
Reviewed By: lattner
Differential Revision: https://reviews.llvm.org/D96359
Currently using LLVM_USE_SANITIZER with a MinGW target leads to a fatal
configuration error due to an unsupported platform. MinGW targets on
clang however implement a few sanitizers, currently ASAN and UBSAN.
This patch enables LLVM_USE_SANITIZER in a MinGW environment as well.
Differential Revision: https://reviews.llvm.org/D95750
