`-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
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
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-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
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
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
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
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
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
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
In some build configurations more than 1.5 might be required.
Paramaterize so it can be changed by the user.
Reviewed By: yamauchi
Differential Revision: https://reviews.llvm.org/D93281
Addressing clang bootstrap under the dynamic linking mode running out of static
allocation of value profile nodes, reported in D81682.
Differential Revision: https://reviews.llvm.org/D92669
Allow overriding the default set of flags used to enable UBSan when
building llvm.
This can be used to test new checks or opt out of certain checks.
Differential Revision: https://reviews.llvm.org/D89439
Configure default value of `LLVM_ENABLE_WARNINGS` in `HandleLLVMOptions.cmake`.
`LLVM_ENABLE_WARNINGS` is documented as ON by default, but `HandleLLVMOptions` assumes the default has been set somewhere else. If it has not been explicitly set, then `HandleLLVMOptions` implicitly uses OFF as a default.
This removes the various `option()` declarations in favor of a single declaration in `HandleLLVMOptions`. This will prevent the unwanted use of `-w` that is mentioned in a couple of the comments.
Reviewed By: DavidTruby, #libunwind, JDevlieghere, compnerd
Differential Revision: https://reviews.llvm.org/D87243
Tests on Solaris/sparcv9 currently show about 250 failures when building
with gcc, most of them like the following:
FAIL: LLVM-Unit :: Support/./SupportTests/TaskQueueTest.UnOrderedFutures (4269 of 67884)
******************** TEST 'LLVM-Unit :: Support/./SupportTests/TaskQueueTest.UnOrderedFutures' FAILED ********************
Note: Google Test filter = TaskQueueTest.UnOrderedFutures
[==========] Running 1 test from 1 test case.
[----------] Global test environment set-up.
[----------] 1 test from TaskQueueTest
[ RUN ] TaskQueueTest.UnOrderedFutures
0 SupportTests 0x0000000100753b20 llvm::sys::PrintStackTrace(llvm::raw_ostream&) + 32
1 SupportTests 0x0000000100752974 llvm::sys::RunSignalHandlers() + 68
2 SupportTests 0x0000000100752b18 SignalHandler(int) + 372
3 libc.so.1 0xffffffff7eedc800 __sighndlr + 12
4 libc.so.1 0xffffffff7eecf23c call_user_handler + 852
5 libc.so.1 0xffffffff7eecf594 sigacthandler + 84
6 SupportTests 0x00000001006f8cb8 std:🧵:_State_impl<std:🧵:_Invoker<std::tuple<llvm::ThreadPool::ThreadPool(llvm::ThreadPoolStrategy)::'lambda'()> > >::_M_run() + 512
7 libstdc++.so.6.0.28 0xfffffffc628117cc execute_native_thread_routine + 16
8 libc.so.1 0xffffffff7eedc6a0 _lwp_start + 0
Since it's effectively impossible to debug such a `SEGV` in a `Release`
build, I tried a `Debug` build instead, only to find that the failures had
gone away.
Further investigation revealed that most of the issue centers around
`llvm/lib/Support/ThreadPool.cpp`. That file is built with `-O3 -fPIC` in
a `Release` build. The failure vanishes if
- compiling without `-fPIC`
- compiling with `-O -fPIC`
- linking with GNU `ld` instead of Solaris `ld`
It has meanwhile been determined that `gcc` doesn't correctly heed some TLS
code sequences. To make things worse, Solaris `ld` doesn't properly
validate its assumptions against the input, generating wrong code.
`gld` like `gcc` is more liberal here and correctly deals with the code it
gets fed from `gcc`.
There's PR target/96607: GCC feeds SPARC/Solaris linker with unrecognized
TLS sequences <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96607> now.
An attempt to build with `-DLLVM_ENABLE_PIC=Off` initially failed since
neither `libRemarks.so` (D85626 <https://reviews.llvm.org/D85626>) nor
`LLVMPolly.so` (D85627 <https://reviews.llvm.org/D85627>) heed that option.
Even with that fixed, a few codegen failures remain.
Next I tried to build just `ThreadPool.cpp` with `-O -fPIC`. While that
fixed the vast majority of the failures, 16 `LLVM :: CodeGen/X86` failures
remained.
Given that that solution was both incomplete and fragile, I went for
building the whole tree with `-O -fPIC` for `Release` and `RelWithDebInfo`
builds.
As detailed in Bug 47304, 2-stage builds also show large numbers of
failures when building with `-O3` or `-O2`, which are likewise worked
around by building with `-O` until they are sufficiently analyzed and
fixed.
This way, all failures relative to a `Debug` build go away.
Tested on `sparcv9-sun-solaris2.11`.
Differential Revision: https://reviews.llvm.org/D85630
This change extend the CMake files with the necessary additions
to build LLVM for z/OS.
Reviewed By: hubert.reinterpretcast
Differential Revision: https://reviews.llvm.org/D83866
The issue with LLVM_ENABLE_LLD is that it just passes -fuse-ld=lld
to compiler/linker options which makes sense only for those platforms
where cmake invokes a compiler driver for linking. On Windows (MSVC) cmake
invokes the linker directly and requires CMAKE_LINKER to be specified
otherwise it defaults CMAKE_LINKER to be link.exe.
This patch allows BOOTSTRAP_LLVM_ENABLE_LLD to set CMAKE_LINKER in two cases:
* if building for host Windows,
* if crosscompiling for target Windows.
It also skips adding '-fuse-ld=lld' to make lld-link not warning
about 'unknown argument'.
This fixes build with `clang/cmake/caches/DistributionExample.cmake`
on Windows.
Reviewed By: phosek
Differential Revision: https://reviews.llvm.org/D80873
add_compile_options is more sensitive to its location in the file than add_definitions--it only takes effect for sources that are added after it. This updated patch ensures that the add_compile_options is done before adding any source files that depend on it.
Using add_definitions caused the flag to be passed to rc.exe on Windows and thus broke Windows builds.
After lots of follow-up fixes, there are still problems, such as
-Wno-suggest-override getting passed to the Windows Resource Compiler
because it was added with add_definitions in the CMake file.
Rather than piling on another fix, let's revert so this can be re-landed
when there's a proper fix.
This reverts commit 21c0b4c1e8.
This reverts commit 81d68ad27b.
This reverts commit a361aa5249.
This reverts commit fa42b7cf29.
This reverts commit 955f87f947.
This reverts commit 8b16e45f66.
This reverts commit 308a127a38.
This reverts commit 274b6b0c7a.
This reverts commit 1c7037a2a5.
A previous patch added -Wsuggest-override using a simple add_flag_if_supported(). This causes lots of warnings in LLVM when building with older GCC versions (< 9.2) which suggest adding override to functions that are only marked final. The current flags in both GCC >=9.2 and Clang accept plain final as equivalent to override final.
This patch adds logic to detect versions of -Wsuggest-override that warn on void foo() final and disables them to avoid warning spam in builds using older GCC's. This has the added minor benefit of getting rid of the useless C_SUPPORTS_SUGGEST_OVERRIDE_FLAG CMake cache variable which was set by add_flag_if_supported().
Differential Revision: https://reviews.llvm.org/D84292
This patch adds Clang's new (and GCC's old) -Wsuggest-override to the warning flags for the LLVM build. The warning is a stronger form of -Winconsistent-missing-override which warns _everywhere_ that override is missing, not just in places where it's inconsistent within a class.
Some directories in the monorepo need the warning disabled for compatibility's, or sanity's, sake; in particular, libcxx/libcxxabi, and any code implementing or interoperating with googletest, googlemock, or google benchmark (which do not themselves use override). This patch adds -Wno-suggest-override to the relevant CMakeLists.txt's to accomplish this.
Differential Revision: https://reviews.llvm.org/D84126
The name of the make program does not necessarily match "ninja",
especially if an alternative implementation like samurai is used.
Using CMAKE_GENERATOR is a more robust detection method, and is
already used elsewhere in this file.
Differential revision: https://reviews.llvm.org/D77091
Followup to b8000c0ce8, the library path needs to go in
CMAKE_MODULE_LINKER_FLAGS too, for the sake of a few files
like LLVMHello.dll.
Reviewed By: hans
Differential Revision: https://reviews.llvm.org/D82888
We want to make sure that LINKER_IS_LLD_LINK is properly set - in
this case it shouldn't be set when building for MinGW.
Then we want to make the test for it correct and finally include
the option to build with thinlto cache since the MinGW driver now
supports that.
Differential Revision: https://reviews.llvm.org/D80493
Summary:
The `-bcdtors:mbr` option causes processing for constructors and
destructors to omit otherwise-unreferenced members of static libraries,
matching the processing done on Linux, where `--whole-archive` is not
the default. Applying this option is desirable for reducing the
footprint of an installation.
Reviewed By: daltenty
Differential Revision: https://reviews.llvm.org/D79749
Summary:
Besides just generating and consuming the lists, this includes:
* Calling nm with the right options in extract_symbols.py. Such as not
demangling C++ names, which AIX nm does by default, and accepting both
32/64-bit names.
* Not having nm sort the list of symbols or we may run in to memory
issues on debug builds, as nm calls a 32-bit sort.
* Defaulting to having LLVM_EXPORT_SYMBOLS_FOR_PLUGINS on for AIX
* CMake versions prior to 3.16 set the -brtl linker flag globally on
AIX. Clear it out early on so we don't run into failures. We will set
it as needed.
Reviewers: jasonliu, DiggerLin, stevewan, hubert.reinterpretcast
Reviewed By: hubert.reinterpretcast
Subscribers: hubert.reinterpretcast, mgorny, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D70972
Prior to this change, for a few compiler-rt libraries such as ubsan and
the profile library, Clang would embed "-defaultlib:path/to/rt-arch.lib"
into the .drective section of every object compiled with
-finstr-profile-generate or -fsanitize=ubsan as appropriate.
These paths assume that the link step will run from the same working
directory as the compile step. There is also evidence that sometimes the
paths become absolute, such as when clang is run from a different drive
letter from the current working directory. This is fragile, and I'd like
to get away from having paths embedded in the object if possible. Long
ago it was suggested that we use this for ASan, and apparently I felt
the same way back then:
https://reviews.llvm.org/D4428#56536
This is also consistent with how all other autolinking usage works for
PS4, Mac, and Windows: they all use basenames, not paths.
To keep things working for people using the standard GCC driver
workflow, the driver now adds the resource directory to the linker
library search path when it calls the linker. This is enough to make
check-ubsan pass, and seems like a generally good thing.
Users that invoke the linker directly (most clang-cl users) will have to
add clang's resource library directory to their linker search path in
their build system. I'm not sure where I can document this. Ideally I'd
also do it in the MSBuild files, but I can't figure out where they go.
I'd like to start with this for now.
Reviewed By: hans
Differential Revision: https://reviews.llvm.org/D65543
Summary:
This patch add the dataflow option to LLVM_USE_SANITIZER and documents
it.
Tested via check-cxx (wip to fix the errors).
Reviewers: morehouse, #libc!
Subscribers: mgorny, cfe-commits, libcxx-commits
Tags: #clang, #libc
Differential Revision: https://reviews.llvm.org/D78390
This handles not paths embedded in debug info, but also in sources.
Since the use of this flag is controlled by an option, rather than
replacing the new option, we add a new option.
Differential Revision: https://reviews.llvm.org/D76018
Summary:
Related to D75672, this patch adds EVT::isFixedLengthVector to determine
if the underlying vector type is of fixed length.
An assert is introduced in EVT::getVectorNumElements that triggers for
types that aren't fixed length. This is currently guarded by a flag
added D75297 that is off by default and has been renamed to the more
generic ENABLE_STRICT_FIXED_SIZE_VECTORS.
Ideally we want to get rid of getVectorNumElements but a quick grep
shows there are >350 uses in lib/CodeGen and 75 in lib/Target/AArch64
alone. All of these probably aren't EVT::getVectorNumElements (some may
be the MVT equivalent), but there are many places to fixup and having
the assert on by default would make the SVE upstreaming effort
difficult.
Reviewers: sdesmalen, efriedma, ctetreau, huntergr, rengolin
Reviewed By: efriedma
Subscribers: mgorny, kristof.beyls, hiraditya, danielkiss, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D76376
This patch removes compiler runtime assertions that ensure the implicit
conversion are only guaranteed to work for fixed-width vectors.
With the assert it would be impossible to get _anything_ to build until
the
entire codebase has been upgraded, even when the indiscriminate uses of
the size as uint64_t would work fine for both scalable and fixed-width
types.
This issue will need to be addressed differently, with build-time errors
rather than assertion failures, but that effort falls beyond the scope
of this patch.
Returning the scalable size and avoiding the assert in getFixedSize()
is a temporary stop-gap in order to use LLVM for compiling and using
the SVE ACLE intrinsics.
Reviewers: efriedma, huntergr, rovka, ctetreau, rengolin
Reviewed By: efriedma
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D75297
Summary:
Enabling _GLIBCXX_DEBUG (implied by LLVM_ENABLE_EXPENSIVE_CHECKS) causes
std::min_element (and presumably others) to no longer be constexpr, which
in turn causes the build to fail.
This seems like a bug in the GCC STL. This change works around it.
Change-Id: I5fc471caa9c4de3ef4e87aeeac8df1b960e8e72c
Reviewers: tstellar, hans, serge-sans-paille
Differential Revision: https://reviews.llvm.org/D75199
Summary:
- Add `-gsplit-dwarf` as an option instead of a definition.
- Only add that option on compilers supporting dwarf splitting, such as clang
and gcc.
Reviewers: echristo, pcc
Subscribers: mgorny, aprantl, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D75328
Haruki Imai