GCC recently started setting constructor priority on init_have_lse_atomics [1]
to avoid undefined initialization order with respect to other initializers,
causing accidental use of ll/sc intrinsics on targets where this was not
intended (which presents a minor performance problem as well as a
compatibility problem for users wanting to use the rr debugger). I initially
thought compiler-rt does not have the same issue as libgcc, since it looks
like we're already setting init priority on the constructor.
Unfortuantely, it does not appear that the HAVE_INIT_PRIORITY check is ever
performed anyway, so despite appearances the init priority was not actually
applied. Fix that by applying the init priority unconditionally. It has been
supported in clang ever since it was first introduced and in any case for
more than 14 years in both gcc and clang. MSVC is already excluded from this
code path and we're already using constructors with init priority elsewhere
in compiler-rt without additional check (though mostly in the sanitizer
runtime, which may have more narrow target support). Regardless, I believe
that for our supported compilers, if they support the constructor attribute,
they should also support init priorities.
While we're here, change the init priority from 101, which is the highest
priority for end user applications, to instead use one of the priority levels
reserved for implementations (1-100; lower integers are higher priority).
GCC ended up using `90`, so this commit aligns the value in compiler-rt
to the same value to ensure that there are no subtle initialization order
differences between libgcc and compiler-rt.
[1] 75c4e4909a
Differential Revision: https://reviews.llvm.org/D126424
Use Fuchsia's zx_system_get_features API to determine
whether LSE atomics are available on the machine.
Reviewed By: abrachet
Differential Revision: https://reviews.llvm.org/D118839
Using the out-of-line LSE atomics helpers for AArch64 on FreeBSD also
requires adding support for initializing __aarch64_have_lse_atomics
correctly. On Linux this is done with getauxval(3), on FreeBSD with
elf_aux_info(3), which has a slightly different interface.
Differential Revision: https://reviews.llvm.org/D109330
Support -march=sapphirerapids for x86.
Compare with Icelake Server, it includes 14 more new features. They are
amxtile, amxint8, amxbf16, avx512bf16, avx512vp2intersect, cldemote,
enqcmd, movdir64b, movdiri, ptwrite, serialize, shstk, tsxldtrk, waitpkg.
Reviewed By: craig.topper
Differential Revision: https://reviews.llvm.org/D86503
Instead of ANDing with a one hot mask representing the bit to
be tested, we were ANDing with just the bit number. This tests
multiple bits none of them the correct one.
This caused skylake-avx512, cascadelake and cooperlake to all
be misdetected. Based on experiments with the Intel SDE, it seems
that all of these CPUs are being detected as being cooperlake.
This is bad since its the newest CPU of the 3.
These aren't used in compiler-rt, but I plan to make a similar
change to the equivalent code in Host.cpp where the mapping from
type/subtype is an unnecessary complication. Having the CPU strings
here will help keep the code somewhat synchronized.
We need to set the cpu_vendor to a non-zero value to indicate
that we already called __cpu_indicator_init once.
This should only happen on a 386 or 486 CPU.
Brand index was a feature some Pentium III and Pentium 4 CPUs.
It provided an index into a software lookup table to provide a
brand name for the CPU. This is separate from the family/model.
It's unclear to me why this index being non-zero was used to
block checking family/model. None of the CPUs that had a non-zero
brand index are supported by __builtin_cpu_is or target
multi-versioning so this should have no real effect.
This adds the family/model returned by CPUID for some Intel
Comet Lake CPUs. Instruction set and tuning wise these are
the same as "skylake".
These are not in the Intel SDM yet, but these should be correct.
Darwin lazily saves the AVX512 context on first use [1]: instead of checking
that it already does to figure out if the OS supports AVX512, trust that
the kernel will do the right thing and always assume the context save
support is available.
[1] https://github.com/apple/darwin-xnu/blob/xnu-4903.221.2/osfmk/i386/fpu.c#L174
Reviewers: ab, RKSimon, craig.topper
Reviewed By: craig.topper
Subscribers: dberris, JDevlieghere, #sanitizers, llvm-commits
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D70454
Use the uniform single line C++/99 style for code comments.
This is part of the cleanup proposed in "[RFC] compiler-rt builtins
cleanup and refactoring".
Differential Revision: https://reviews.llvm.org/D60352
llvm-svn: 359411
Update formatting to use the LLVM style.
This is part of the cleanup proposed in "[RFC] compiler-rt builtins
cleanup and refactoring".
Differential Revision: https://reviews.llvm.org/D60351
llvm-svn: 359410
Also hide __cpu_inicator_init and __cpu_features2
for similar reasons.
Summary: Make __cpu_model a hidden symbol, to match libgcc.
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D59561
llvm-svn: 356581
For 'cascadelake' this is adding a 'avx512vnni' feature check to the 0x55 skylake-avx512 model check. These CPUs use the same model number and only differ in the stepping number. But the feature flag is simpler than collecting all the stepping numbers.
For 'znver2' this is just syncing with LLVM's Host.cpp.
llvm-svn: 354927
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
Summary: This patch adds additional features and cpus from libgcc. Unfortunately we've overflowed the existing 32-bits of features so we had to add a new __cpu_features2 variable to hold the additional bits. This matches libgcc as far as I can tell.
Reviewers: echristo
Reviewed By: echristo
Subscribers: dberris, llvm-commits
Differential Revision: https://reviews.llvm.org/D53461
llvm-svn: 344830
Summary:
We were missing many feature flags that newer gcc supports and we had our own set of feature flags that gcc didnt' support that were overlapping. Clang's implementation assumes gcc's features list so a mismatch here is problematic.
I've also matched the cpu type/subtype lists with gcc and removed all the cpus that gcc doesn't support. I've also removed the fallback autodetection logic that was taken from Host.cpp. It was the main reason we had extra feature flags relative to gcc. I don't think gcc does this in libgcc.
Once this support is in place we can consider implementing __builtin_cpu_is in clang. This could also be needed for function dispatching that Erich Keane is working on.
Reviewers: echristo, asbirlea, RKSimon, erichkeane, zvi
Reviewed By: asbirlea
Subscribers: dberris, llvm-commits
Differential Revision: https://reviews.llvm.org/D35214
llvm-svn: 307878
Keno Fischer