Clang 13 has a -fsanitize-coverage -fno-semantic-interposition bug (D117190)
which may lead to
`relocation R_X86_64_PC32 cannot be used against symbol` linker error
in -DLLVM_USE_SANITIZE_COVERAGE=ON build when a shared object is built (e.g.
-DLLVM_BUILD_LLVM_DYLIB=on).
For simplicity, just disallow Clang 13 entirely.
Note: GCC -fPIC performance benefits from -fno-semantic-interposition
dramatically. Clang benefits little. Using this option is more for a dogfood
purpose to test correctness of this option, because in the wild some important
packages like CPython uses this option.
Differential Revision: https://reviews.llvm.org/D117183
This diff enables users to override CMAKE_C_ARCHIVE_CREATE & CMAKE_CXX_ARCHIVE_CREATE
(currently set in HandleLLVMOptions.cmake).
For example, one can specify
cmake -DCMAKE_C_ARCHIVE_CREATE="<CMAKE_AR> TDqc <TARGET> <LINK_FLAGS> <OBJECTS>" \
-DCMAKE_CXX_ARCHIVE_CREATE="<CMAKE_AR> TDqc <TARGET> <LINK_FLAGS> <OBJECTS>" ...
to make the build create thin archives instead of regular ones.
For a clean run `ninja lld` using thin archives seems to reduce the size
of the build directory from ~14GB to ~8GB
Differential revision: https://reviews.llvm.org/D116850
This is the patch for LLVM proper in my series for adding GNUInstallDirs support in all project.
Additionally:
Create a new `CACHE STRING` variable, `LLVM_EXAMPLES_INSTALL_DIR`, to control where the examples are installed on analogy with the other variables.
---
This patch supersedes D28234, which tried to do the same thing but hand-rolled without GNUInstallDirs.
This patch nearly reverts commit 3 0fc88bf1dc15a72e2d9809d28019d386b7a7cc0, which was a revert of a prior attempt."
(I had to add a space here or else Phabricator detects a reference cycle and won't let me do the form submit.)
Reviewed By: compnerd
Differential Revision: https://reviews.llvm.org/D100810
Users could pass flags by environment variables like CFLAGS/CXXFLAGS/LDFLAGS
or by using CMAKE_<LANG>_FLAGS_INIT/CMAKE_<t>_LINKER_FLAGS_INIT. So this
toolchain file should append to INIT flags instead. Otherwise, user
flags would be discarded here by assigning to CMAKE_<LANG>_FLAGS
directly.
Reviewed By: smeenai, mstorsjo
Differential Revision: https://reviews.llvm.org/D116709
@beanz tells me it should in fact exists, and it would be bad to put a
list of dirs in `LLVM_LIBRARY_DIR`. I am therefore making some changes
to help avoid this an other mistakes:
- Use a separate `LLVM_CONFIG_LIBRARY_DIR` (no "S") variable so we don't
start putting a list in `LLVM_LIBRARY_DIR` by mistake.
- Define the individual dir variables first, and the define the list of
dirs variables programmatically.
Also, I rearranged the definitions of the "regular" single dirs below so
`LLVM_BINARY_DIR`, which is the unsuffixed one, comes first before the
suffixed ones.
Reviewed By: beanz
Differential Revision: https://reviews.llvm.org/D116497
See the docs in the new function for details.
I think I found every instance of this copy pasted code. Polly could
also use it, but currently does something different, so I will save the
behavior change for a future revision.
We get the shared, non-installed CMake modules following the pattern
established in D116472.
It might be good to have LLD and Flang also use this, but that would be
a functional change and so I leave it as future work.
Reviewed By: beanz, lebedev.ri
Differential Revision: https://reviews.llvm.org/D116521
Include the value of `ZLIB_ROOT` in `LLVMConfig.cmake` so `FindZLIB` can pick it up. This fixes an issue where ZLIB is not found on AIX runtimes despite specifying `-DZLIB_ROOT`.
Reviewed By: daltenty
Differential Revision: https://reviews.llvm.org/D116235
Add CMake variable LLVM_EXTERNAL_PROJECT_BUILD_TOOL_ARGS to allow
arguments to be passed to the native tool used in CMake --build
invocations for external projects.
Can be used to pass extra arguments for enhanced versions of build
tools, e.g. distributed build options.
Differential Revision: https://reviews.llvm.org/D115815
As Visual Studio's CMake support is getting better and better the line
between IDE generator and non-IDE generators is blurring. Visual Studio
2019 and later have a very useful UI that can handle all of the various
targets we create, but if they are unsorted it is wildly unwieldy.
This change sorts the lit testsuite targets and per-component install
targets into folders, which are not generated for IDE generators but
are generated by default under Visual Studio's CMake + Ninja
integration.
This reverts 8cb7876cb3 and follow-ups.
GNU ld/gold/ld.lld -O has nothing to do with any code related linker optimizations.
It has very small benefit (save 144Ki (.hash, .gnu_hash) with GNU ld, save 0.7%
.debug_str with gold/ld.lld) while it makes gold/ld.lld significantly slower
when linking RelWithDebInfo clang (gold: 16.437 vs 19.488; ld.lld: 1.882 vs 4.881).
When looking at building the generator for regalloc, we realized we'd
need quite a bit of custom logic, and that perhaps it'd be easier to
just have each usecase (each kind of mlgo policy) have it's own
stand-alone test generator.
This patch just consolidates the old `config.py` and
`generate_mock_model.py` into one file, and does away with
subdirectories under Analysis/models.
This reverts 3816c53f04 and removes follow-up
fixups.
The original intention was to show error earlier (posix_fallocate time) than
later for ld.lld but it appears to cause some problems which make it not free.
* FreeBSD ZFS: EINVAL, not too bad.
* FreeBSD UFS: according to khng "devastatingly slow on freebsd because UFS on freebsd does not have preallocation support like illumos. It zero-fills."
* NetBSD: maybe EOPNOTSUPP
* Linux tmpfs: unless tmpfs is set up to use huge pages (requires CONFIG_TRANSPARENT_HUGE_PAGECACHE=y), I can consistently demonstrate ~300ms delay for a 1.4GiB output.
* Linux ext4: I don't measure any benefit, either backed by a hard disk or by a file in tmpfs.
* The current code organization of `defined(HAVE_POSIX_FALLOCATE)` costs us a macro dispatch for AIX.
I think we should just remove it. I think if posix_fallocate ever finds demonstrable benefit,
it is likely Linux specific and will not need HAVE_POSIX_FALLOCATE, and possibly opt-in by some specific programs.
In a filesystem with CoW and compression, the ENOSPC benefit may be lost as well.
Reviewed By: khng300
Differential Revision: https://reviews.llvm.org/D115957
See the discussion in D30906 for how it must be robust to downstream
projects that might not use `GNUInstallDirs`.
I think an easier approach is just to include `GNUInstallDirs` so that
we can always rely on it. Looking at its definition in
https://gitlab.kitware.com/cmake/cmake/-/blob/master/Modules/GNUInstallDirs.cmake
it appears safe to include multiple times.
I am trying this out because we will face the same problem many times
over if we use `GNUInstallDirs` more widely, as proposed in D99484 and
its parent revisions, since we do not know what downstream projects do
and rather not break them.
Reviewed By: phosek
Differential Revision: https://reviews.llvm.org/D115601
Just defensive CMake-ing. I pulled this from D115544 and D99484 which
are blocked on some lldb CI failures I don't yet understand. Hoping to land
something smaller in the meantime.
Reviewed By: #libc, ldionne
Differential Revision: https://reviews.llvm.org/D115566
This reverts commit 492de35df4.
I tried to apply John's changes in 8d897ec915 that were expected to
fix his patch but that didn't work unfortunately.
Reverting this again to fix the macOS bots and leave him more time to
investigate the issue.
This reverts commit 797b50d4be.
See the original D99484. @mib who noticed the original problem could not longer
reproduce it, after I tried and also failed. We are threfore hoping it went
away on its own!
Reviewed By: mib
Differential Revision: https://reviews.llvm.org/D115544
Improves cross-distro portability of LLVM cmake package by resolving paths for
terminfo and libffi via import targets.
When LLVMExports.cmake is generated for installation, it contains absolute
library paths which are likely to be a common cause of portability issues. To
mitigate this, the discovery logic for these dependencies is refactored into
find modules which get installed alongside LLVMConfig.cmake. The result is
cleaner, cmake-friendly management of these dependencies that respect the
environment of the LLVM package importer.
Reviewed By: JDevlieghere
Differential Revision: https://reviews.llvm.org/D114327
This patch changes it to ignorelist and contains a filename change for the
.txt file that's called.
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D113689
When cross-compiling LLVM in an environment where there //is// an
objdump binary available but it does not understand the target
platform's object file format, extract_symbols.py fails, because its
initial check for tool availability decides that the existence of
objdump at all is good enough to settle on it as the tool of choice.
In such an environment it's useful to work around this by telling
extract_symbols.py to use llvm-readobj instead. The script itself has
an option for that, but its invocation in AddLLVM.cmake wasn't
providing a mechanism to add extra options passed through for the
cmake command line.
Reviewed By: DavidSpickett
Differential Revision: https://reviews.llvm.org/D113557
Add a warning to TableGen for unused template arguments in classes and
multiclasses, for example:
multiclass Foo<int x> {
def bar;
}
$ llvm-tblgen foo.td
foo.td:1:20: warning: unused template argument: Foo::x
multiclass Foo<int x> {
^
A flag '--no-warn-on-unused-template-args' is added to disable the
warning. The warning is disabled for LLVM and sub-projects if
'LLVM_ENABLE_WARNINGS=OFF'.
Reviewed By: RKSimon
Differential Revision: https://reviews.llvm.org/D109359
LLVM_LINKER_IS_LLD is now set with LLVM_ENABLE_LLD=ON (or LLVM_USER_LINKER=lld)
even on APPLE, and we pass -Wl,-order_file when LLVM_LINKER_IS_LLD on APPLE
too.
To make this straightforward, change the linker detection logic to go through
the compiler driver on APPLE like on the other platforms.
No intended behavior change if LLVM_ENABLE_LLD isn't set.
Differential Revision: https://reviews.llvm.org/D113021
This is a new draft of D28234. I previously did the unorthodox thing of
pushing to it when I wasn't the original author, but since this version
- Uses `GNUInstallDirs`, rather than mimics it, as the original author
was hesitant to do but others requested.
- Is much broader, effecting many more projects than LLVM itself.
I figured it was time to make a new revision.
I am using this patch (and many back-ports) as the basis of
https://github.com/NixOS/nixpkgs/pull/111487 for my distro (NixOS). It
looked like people were generally on board in D28234, but I make note of
this here in case extra motivation is useful.
---
As pointed out in the original issue, a central tension is that LLVM
already has some partial support for these sorts of things. For example
`LLVM_LIBDIR_SUFFIX`, or `COMPILER_RT_INSTALL_PATH`. Because it's not
quite clear yet what to do about those, we are holding off on changing
libdirs and `compiler-rt`. for this initial PR.
---
On the advice of @lebedev.ri, I am splitting this up a bit per
subproject, starting with LLVM. To allow it to be more easily reviewed. This and the subsequent patch must be landed together, as this will not build alone. But the rest can be landed on their own.
Reviewed By: compnerd
Differential Revision: https://reviews.llvm.org/D100810
Forward the LLVM_ENABLE_RUNTIMES cmake variable in the cross compilation
invocation.
Now that passing libcxx must be specified in LLVM_ENABLE_RUNTIMES
instead of LLVM_ENABLE_PROJECTS, the LLDB's sanity check for libcxx
trips up (in the cross compilation case) because the runtimes are not
forwarded. This patch fixes that.
Differential revision: https://reviews.llvm.org/D112855
The xar file format has been deprecated since macOS 12.0, causing a
warning to be printed:
warning: 'xar_open' is deprecated: first deprecated in macOS 12.0 -
xar is a deprecated file format and should not be used.
Disable xar support when the macosx deployment target is greater or
equal to 12.0.
Differential revision: https://reviews.llvm.org/D112849
- Both LLVM_REQUIRES_RTTI and LLVM_REQUIRES_EH are internal flags that
individual targets can use to force RTTI/EH. Turning off
LLVM_REQUIRES_RTTI should honor if that variable is set explicitly for
an individual target.
Set `HAVE_CXX_ATOMICS_WITHOUT_LIB` or `HAVE_LIBATOMIC` when build LLVM with xlclang. With these macros set, libraries like libLLVMSupport are able to know whether it's necessary to add `-latomic` to dependent system libs. If `HAVE_LIBATOMIC` is set, `llvm-config --system-libs` appends `-latomic` to its output.
Reviewed By: jsji
Differential Revision: https://reviews.llvm.org/D111782
This finds the curl libraries if LLVM_ENABLE_CURL is set. This is needed
to implement the debuginfod client library in LLVM.
Patch By: noajshu
Differential Revision: https://reviews.llvm.org/D111238
mold says it is compatible with GNU ld and gold linkers:
```
$ mold -v
mold 0.9.5 (compatible with GNU ld and GNU gold)
```
And thus it currently gets detected as Gold.
With the following diff, CMake now correctly reports the linker name, and mold keeps being identified as Gold internally for now.
Reviewed By: ldionne, MaskRay
Differential Revision: https://reviews.llvm.org/D110035
This reverts commit 6d7b3d6b3a.
Breaks running cmake with `-DCLANG_ENABLE_STATIC_ANALYZER=OFF`
without turning off CLANG_TIDY_ENABLE_STATIC_ANALYZER.
See comments on https://reviews.llvm.org/D109611 for details.
Since https://reviews.llvm.org/D87118, the StaticAnalyzer directory is
added unconditionally. In theory this should not cause the static analyzer
sources to be built unless they are referenced by another target. However,
the clang-cpp target (defined in clang/tools/clang-shlib) uses the
CLANG_STATIC_LIBS global property to determine which libraries need to
be included. To solve this issue, this patch avoids adding libraries to
that property if EXCLUDE_FROM_ALL is set.
In case something like this comes up again: `cmake --graphviz=targets.dot`
is quite useful to see why a target is included as part of `ninja all`.
Reviewed By: thakis
Differential Revision: https://reviews.llvm.org/D109611
Visibility options currently have limited support on AIX and may cause warnings or errors
depending on the build compiler used.
Reviewed By: ZarkoCA
Differential Revision: https://reviews.llvm.org/D108467
This updates llvm/utils/sysroot.py to include the "DIA SDK" folder in the
sysroot.
It also updates the build to look for the DIA SDK there if a sysroot is set.
This requires moving LLVM_WINSYSROOT to config-ix.cmake.
For the GN build, I chose to pass a qualified path to diaguids in libs instead
of pushing a config with a `/libpath:` flag. The former requires a GN with
https://gn-review.googlesource.com/c/gn/+/12200, the latter requires D109624.
The former is more like the cmake build, arguably a bit simpler, and it's
easier to check for the wrong GN revision and easier to update GN.
Differential Revision: https://reviews.llvm.org/D109708
The original change to add the workaround is from 10 years ago and a lot has happened with msvc and cmake and llvm's usage of cmake since and we no longer need the workaround for any scenarios that I am aware of. Build more is now correctly configured for multi-configuration generators such as Visual Studio.
The workaround is, however, causing issues with some of the recent mlir tests as because of the workaround we cannot correctly determine whether assertions are enabled (see https://reviews.llvm.org/D105961).
The original change is:
```
commit b46fdac460
Author: Andrew Trick <atrick@apple.com>
Date: Tue Jun 28 16:32:01 2011
cmake: Our MSVC build does not support config-time build mode.
llvm-svn: 134008
```
Reviewed By: mehdi_amini
Differential Revision: https://reviews.llvm.org/D109521
so that it gets installed in LLVM_INSTALL_TOOLCHAIN_ONLY builds,
such as used by the Windows installer.
Differential revision: https://reviews.llvm.org/D109358
This is a pretty small bit of CMake goop to generate code coverage
reports. I always forget the right script invocation and end up
fumbling around too much.
Wouldn't it be great to have targets that "Just Work"?
Well, I thought so.
At present this only really works correctly for LLVM, but I'll extend
it in subsequent patches to work for subprojects.
Reviewed By: phosek
Differential Revision: https://reviews.llvm.org/D109019
At least as of CMake 3.20.3, the CMake platform file for Linux doesn't
define the file type prefix and suffix variables, relying on them being
implicitly empty when they're unset. If we're cross-compiling targeting
Windows on a Linux machine, the values of these prefixes and suffixes
populated by the Windows platform file will still be set after including
the Linux platform file, so we'll incorrectly assume the ".exe" suffix
for the host machine. Explicitly unset the variables before including
the platform file, to prevent any previous values from leaking. Thanks
@beanz for suggesting the fix.
Reviewed By: beanz
Differential Revision: https://reviews.llvm.org/D108473
After some moment VS solution generated with LLVM_OPTIMIZED_TABLEGEN started to
generate all .inc files for each build. The reason was it had
"<path to native tablegen>/llvm-tblgen" without .exe as a dependency.
Differential Revision: https://reviews.llvm.org/D107898
It's sometimes useful to use these directives when dealing with
external projects:
target_link_directories
target_link_libraries
target_include_directories
However, under certain circumstances,
llvm_add_library can generate multiple targets. We need to transfer
these properties to the new targets. Note that using a generator
expression is necessary because these properties will only be set
after llvm_add_library is called.
Differential Revision: https://reviews.llvm.org/D108098
libgcc and libunwind have different flavours of __register_frame. Both
flavours are already correctly handled, except that the code to handle
the libunwind flavour is guarded by __APPLE__. This change uses the
presence of __unw_add_dynamic_fde in libunwind instead to detect whether
libunwind is used, rather than hardcoding it as Apple vs. non-Apple.
Fixes PR44074.
Thanks to Albert Jin <albert.jin@gmail.com> and Chris Schafmeister
<chris.schaf@verizon.net> for identifying the problem.
Reviewed By: lhames
Differential Revision: https://reviews.llvm.org/D106129
Consistently use 'w64' as vendor string; it was 'pc' for the original
i686 triple added in 91bd6c922d, but the later x86_64 triple
used 'w64' as vendor, added in d6c1f37f86.
When the arm triples were added in c84ad73a27, the differing
vendors were copied over accidentally to the arm targets too.
When using per-target runtime directories, having inconsistent vendor
parts of the target triples is fatal.
Differential Revision: https://reviews.llvm.org/D107894
In MSVC mode, CMake provides CMAKE_C_COMPILER_ARCHITECTURE_ID,
which should be accurate for what the compiler produces. Keep
the old CMAKE_C_SIZEOF_VOID_P based fallback in case this
doesn't provide matches.
In GCC/MinGW mode, CMake doesn't provide that. As we're trying to
guess the default host architecture, use CMAKE_HOST_SYSTEM_PROCESSOR
in combination with the existing CMAKE_C_SIZEOF_VOID_P check to
estimate whether it's x86/x86_64/arm/aarch64.
Differential Revision: https://reviews.llvm.org/D107626
Include the vaue of LLVM_ENABLE_NEW_PASS_MANAGER in generated
LLVMConfig.cmake since it is needed by clang's build system. This fixes
test failures when the new pass manager is enabled (i.e. by default)
by having clang's CMake files correctly detect that and skip relevant
tests.
Differential Revision: https://reviews.llvm.org/D107628
Use absolute path to link z3 to allow builds both on windows and linux
since the library name is platform dependent for Z3 (libz3 on Windows
and z3 on Linux) and MSVC does not recognized -L and -l options.
Fix CMAKE_CROSSCOMPILING that does not work correctly since it uses
Z3_BUILD_VERSION instead of Z3_BUILD_NUMBER
Fix building with the static version of z3 library (supersedes D80227).
- Build the Z3 version detection code as C++, since the static
library brings in libstdc++ symbols
- Detect threading support and link against threading, in the
(likely) case Z3 was built with threads
Exposed compilation error from building a program that is used to detect
z3 version in the warning message, to simplify troubleshooting.
Reviewed By: JDevlieghere
Differential Revision: https://reviews.llvm.org/D106131
Currently when linking LLVM against Libxml2, a simple check is performed to check whether it can be linked successfully. This check currently adds the include directories and the libraries for libxml2, but not definitions found by the config.
This causes issues on Windows when trying to link against a static libxml2. Libxml2 requires LIBXML_STATIC to be defined in the preprocessor to be able to link statically. This definition is put into LIBXML2_DEFINITIONS in the cmake config, but not properly forwarded to check_symbol_exists leading to it failing as it could not find xmlReadMemory in a DLL.
This patch simply appends the content of LIBXML2_DEFINITIONS to the symbol check definitions, fixing the issue.
Differential Revision: https://reviews.llvm.org/D106740
This is just a workaround. Pass the `-mllvm,-O0` link flags only if its
not ThinLTO. Doing that with ThinLTO currently results in an error:
```
Remaining virtual register operands
UNREACHABLE executed at .../llvm/lib/CodeGen/MachineRegisterInfo.cpp:209!
```
This is referenced in several of the cmake files that are part of an llvm install and it is also useful by downstream components such as onnx-mlir.
Differential Revision: https://reviews.llvm.org/D106686
This patch adds llvm-readobj and the binutils symlink for readelf to
LLVM_TOOLCHAIN_TOOLS.
Tvoid *thread, void *attr,hey are required by some (most?)
autoconf-built libraries, adding these allows me to build newlib with
the toolchain generated this way.
Also opened an issue for that some days ago, see
https://bugs.llvm.org/show_bug.cgi?id=50698
Reviewed By: sbc100
Differential Revision: https://reviews.llvm.org/D104957
`-fno-semantic-interposition` was added for GCC in D102453, but some MLIR tests
on SystemZ failed with GCC<10.3 due to a bug.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D105453
`llvm-strip` does not support `-l`. Apple's `strip` supports `-l`, but
it is not documented, and the latest code doesn't seem to do anything
meaningful. From the old source code drops it seems that `-l` was added
around version 795 of cctools and removed before 898. The code around
the flag usage in 795 talks about problems with kext and forcing the
execution of `ld -r`, which seems a behaviour that is not enforceable in
latest versions of cctools.
The `-l` flag was added in https://reviews.llvm.org/D15133 without a lot
of explanation.
Since the flag is not active, removing it should not modify the
behaviour for most people (except if someone is trying to compile LLVM
with a really old version of `strip`).
Additionally, break the invocation into two different flags, since
`llvm-strip` doesn't at the moment support grouped flags, and other
`strip` implementations should work the same no matter if grouped or
not.
Test Plan:
Using `strip` from Xcode 12.5 in Big Sur to strip the same binary (a
simple Hello World), using both `-Sxl` and `-Sx` produces exactly the
same binary.
Repeating the same process with `clang` results also in the same binary.
Reviewed By: smeenai
Differential Revision: https://reviews.llvm.org/D105243
Synchronizing multiple custom targets requires not only target but also
file dependencies. Building Linalg involves running yaml-gen followed by
tablegen. Currently, these custom targets are only synchronized using a
target dependency resulting in issues in specific incremental build
setups (https://llvm.discourse.group/t/missing-build-cmake-tblgen-dependency/3727/10).
This patch introduces a novel LLVM_TARGET_DEPENDS variable to the
TableGen.cmake file to provide a way to specify file dependencies.
Additionally, it adapts the Linalg CMakeLists.txt to introduce the
necessary file dependency between yaml-gen and tablegen.
Differential Revision: https://reviews.llvm.org/D105272
They are not conducive to being stored in git. Instead, we autogenerate
mock model artifacts for use in tests. Production models can be
specified with the cmake flag LLVM_INLINER_MODEL_PATH.
LLVM_INLINER_MODEL_PATH has two sentinel values:
- download, which will download the most recent compatible model.
- autogenerate, which will autogenerate a "fake" model for testing the
model uptake infrastructure.
Differential Revision: https://reviews.llvm.org/D104251
If the flag is not set, the script saved_model_aot_compile.py in tensorflow will
default it to the correct value. However, in TF 2.5, the way the value is set in
TensorFlowCompile.cmake file triggers a build error.
Reviewed By: mtrofin
Differential Revision: https://reviews.llvm.org/D103972
This is an attempt to fix clang test failures due to 'nonportable-include-path'
warnings on Windows when a path to llvm-project's base directory contains some
uppercase letters (excluding a drive letter).
The issue originates from 2 problems:
* discovery.py loads site config in lower case causing all the paths
based on __file__ and requested within the config file to be in lowercase as well,
* neither os.path.abspath() nor os.path.realpath() (both used to obtain paths of
config files, sources, object directories, etc) do not return paths in the correct
case for Windows (at least consistently for all python versions).
As os.path library doesn't seem to provide any relaible way to restore
the case for paths on Windows, this patch proposes to use pathlib.resolve().
pathlib is a part of Python 3.4 while llvm lit requires Python 3.6.
Reviewed By: Meinersbur
Differential Revision: https://reviews.llvm.org/D103014
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, 2b01a417d7.
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
Fangrui Song