[compiler-rt] [scudo] Use -mcrc32 on x86 when available

Update the hardware CRC32 logic in scudo to support using `-mcrc32`
instead of `-msse4.2`. The CRC32 intrinsics use the former flag
in the ne

[compiler-rt] [scudo] Use -mcrc32 on x86 when available

Update the hardware CRC32 logic in scudo to support using `-mcrc32`
instead of `-msse4.2`. The CRC32 intrinsics use the former flag
in the newer compiler versions, e.g. in clang since 12fa608af44a.
With these versions of clang, passing `-msse4.2` is insufficient
to enable the instructions and causes build failures when `-march` does
not enable CRC32 implicitly:

/var/tmp/portage/sys-libs/compiler-rt-sanitizers-14.0.0/work/compiler-rt/lib/scudo/scudo_crc32.cpp:20:10: error: always_inline function '_mm_crc32_u32' requires target feature 'crc32', but would be inlined into function 'computeHardwareCRC32' that is compiled without support for 'crc32'
return CRC32_INTRINSIC(Crc, Data);
^
/var/tmp/portage/sys-libs/compiler-rt-sanitizers-14.0.0/work/compiler-rt/lib/scudo/scudo_crc32.h:27:27: note: expanded from macro 'CRC32_INTRINSIC'
# define CRC32_INTRINSIC FIRST_32_SECOND_64(_mm_crc32_u32, _mm_crc32_u64)
^
/var/tmp/portage/sys-libs/compiler-rt-sanitizers-14.0.0/work/compiler-rt/lib/scudo/../sanitizer_common/sanitizer_platform.h:132:36: note: expanded from macro 'FIRST_32_SECOND_64'
# define FIRST_32_SECOND_64(a, b) (a)
^
1 error generated.

For backwards compatibility, use `-mcrc32` when available and fall back
to `-msse4.2`. The `<smmintrin.h>` header remains in use as it still
works and is compatible with GCC, while clang's `<crc32intrin.h>`
is not.

Use __builtin_ia32*() rather than _mm_crc32*() when using `-mcrc32`
to preserve compatibility with GCC. _mm_crc32*() are aliases
to __builtin_ia32*() in both compilers but GCC requires `-msse4.2`
for the former, while both use `-mcrc32` for the latter.

Originally reported in https://bugs.gentoo.org/835870.

Differential Revision: https://reviews.llvm.org/D122789

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Revert "[compiler-rt] [scudo] Use -mcrc32 on x86 when available"

This reverts commit 09b53121c323f260ab97cecd067d4e7b3be1bf7c.

Breaks the build with GCC 11.2 on x86_64:

In file included from /home

Revert "[compiler-rt] [scudo] Use -mcrc32 on x86 when available"

This reverts commit 09b53121c323f260ab97cecd067d4e7b3be1bf7c.

Breaks the build with GCC 11.2 on x86_64:

In file included from /home/npopov/repos/llvm-project/compiler-rt/lib/scudo/scudo_crc32.h:27,
from /home/npopov/repos/llvm-project/compiler-rt/lib/scudo/scudo_crc32.cpp:14:
/usr/lib/gcc/x86_64-redhat-linux/11/include/smmintrin.h: In function ‘__sanitizer::u32 __scudo::computeHardwareCRC32(__sanitizer::u32, __sanitizer::uptr)’:
/usr/lib/gcc/x86_64-redhat-linux/11/include/smmintrin.h:846:1: error: inlining failed in call to ‘always_inline’ ‘long long unsigned int _mm_crc32_u64(long long unsigned int, long long unsigned int)’: target specific option mismatch
846 | _mm_crc32_u64 (unsigned long long __C, unsigned long long __V)

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[compiler-rt] [scudo] Use -mcrc32 on x86 when available

Update the hardware CRC32 logic in scudo to support using `-mcrc32`
instead of `-msse4.2`. The CRC32 intrinsics use the former flag
in the ne

[compiler-rt] [scudo] Use -mcrc32 on x86 when available

Update the hardware CRC32 logic in scudo to support using `-mcrc32`
instead of `-msse4.2`. The CRC32 intrinsics use the former flag
in the newer compiler versions, e.g. in clang since 12fa608af44a.
With these compilers, passing `-msse4.2` is insufficient to enable
the instructions and causes build failures when `-march` does not enable
CRC32:

/var/tmp/portage/sys-libs/compiler-rt-sanitizers-14.0.0/work/compiler-rt/lib/scudo/scudo_crc32.cpp:20:10: error: always_inline function '_mm_crc32_u32' requires target feature 'crc32', but would be inlined into function 'computeHardwareCRC32' that is compiled without support for 'crc32'
return CRC32_INTRINSIC(Crc, Data);
^
/var/tmp/portage/sys-libs/compiler-rt-sanitizers-14.0.0/work/compiler-rt/lib/scudo/scudo_crc32.h:27:27: note: expanded from macro 'CRC32_INTRINSIC'
# define CRC32_INTRINSIC FIRST_32_SECOND_64(_mm_crc32_u32, _mm_crc32_u64)
^
/var/tmp/portage/sys-libs/compiler-rt-sanitizers-14.0.0/work/compiler-rt/lib/scudo/../sanitizer_common/sanitizer_platform.h:132:36: note: expanded from macro 'FIRST_32_SECOND_64'
# define FIRST_32_SECOND_64(a, b) (a)
^
1 error generated.

For backwards compatibility, use `-mcrc32` when available and fall back
to `-msse4.2`. The `<smmintrin.h>` header remains in use as it still
works and is compatible with GCC, while clang's `<crc32intrin.h>`
is not.

Originally reported in https://bugs.gentoo.org/835870.

Differential Revision: https://reviews.llvm.org/D122789

show more ...

Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the ne

Update the file headers across all of the LLVM projects in the monorepo
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

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[scudo] CRC32 optimizations

Summary:
This change optimizes several aspects of the checksum used for chunk headers.

First, there is no point in checking the weak symbol `computeHardwareCRC32`
everyt

[scudo] CRC32 optimizations

Summary:
This change optimizes several aspects of the checksum used for chunk headers.

First, there is no point in checking the weak symbol `computeHardwareCRC32`
everytime, it will either be there or not when we start, so check it once
during initialization and set the checksum type accordingly.

Then, the loading of `HashAlgorithm` for SSE versions (and ARM equivalent) was
not optimized out, while not necessary. So I reshuffled that part of the code,
which duplicates a tiny bit of code, but ends up in a much cleaner assembly
(and faster as we avoid an extraneous load and some calls).

The following code is the checksum at the end of `scudoMalloc` for x86_64 with
full SSE 4.2, before:
```
mov rax, 0FFFFFFFFFFFFFFh
shl r10, 38h
mov edi, dword ptr cs:_ZN7__scudoL6CookieE ; __scudo::Cookie
and r14, rax
lea rsi, [r13-10h]
movzx eax, cs:_ZN7__scudoL13HashAlgorithmE ; __scudo::HashAlgorithm
or r14, r10
mov rbx, r14
xor bx, bx
call _ZN7__scudo20computeHardwareCRC32Ejm ; __scudo::computeHardwareCRC32(uint,ulong)
mov rsi, rbx
mov edi, eax
call _ZN7__scudo20computeHardwareCRC32Ejm ; __scudo::computeHardwareCRC32(uint,ulong)
mov r14w, ax
mov rax, r13
mov [r13-10h], r14
```
After:
```
mov rax, cs:_ZN7__scudoL6CookieE ; __scudo::Cookie
lea rcx, [rbx-10h]
mov rdx, 0FFFFFFFFFFFFFFh
and r14, rdx
shl r9, 38h
or r14, r9
crc32 eax, rcx
mov rdx, r14
xor dx, dx
mov eax, eax
crc32 eax, rdx
mov r14w, ax
mov rax, rbx
mov [rbx-10h], r14
```

Reviewers: dvyukov, alekseyshl, kcc

Reviewed By: alekseyshl

Subscribers: aemerson, rengolin, llvm-commits

Differential Revision: https://reviews.llvm.org/D32971

llvm-svn: 302538

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[scudo] Refactor of CRC32 and ARM runtime CRC32 detection

Summary:
ARM & AArch64 runtime detection for hardware support of CRC32 has been added
via check of the AT_HWVAL auxiliary vector.

Following

[scudo] Refactor of CRC32 and ARM runtime CRC32 detection

Summary:
ARM & AArch64 runtime detection for hardware support of CRC32 has been added
via check of the AT_HWVAL auxiliary vector.

Following Michal's suggestions in D28417, the CRC32 code has been further
changed and looks better now. When compiled with full relro (which is strongly
suggested to benefit from additional hardening), the weak symbol for
computeHardwareCRC32 is read-only and the assembly generated is fairly clean
and straight forward. As suggested, an additional optimization is to skip
the runtime check if SSE 4.2 has been enabled globally, as opposed to only
for scudo_crc32.cpp.

scudo_crc32.h has no purpose anymore and was removed.

Reviewers: alekseyshl, kcc, rengolin, mgorny, phosek

Reviewed By: rengolin, mgorny

Subscribers: aemerson, rengolin, llvm-commits

Differential Revision: https://reviews.llvm.org/D28574

llvm-svn: 292409

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[scudo] Separate hardware CRC32 routines

Summary:
As raised in D28304, enabling SSE 4.2 for the whole Scudo tree leads to the
emission of SSE 4.2 instructions everywhere, while the runtime checks on

[scudo] Separate hardware CRC32 routines

Summary:
As raised in D28304, enabling SSE 4.2 for the whole Scudo tree leads to the
emission of SSE 4.2 instructions everywhere, while the runtime checks only
applied to the CRC32 computing function.

This patch separates the CRC32 function taking advantage of the hardware into
its own file, and only enabled -msse4.2 for that file, if detected to be
supported by the compiler.

Another consequence of removing SSE4.2 globally is realizing that memcpy were
not being optimized, which turned out to be due to the -fno-builtin in
SANITIZER_COMMON_CFLAGS. So we now explicitely enable builtins for Scudo.

The resulting assembly looks good, with some CALLs are introduced instead of
the CRC32 code being inlined.

Reviewers: kcc, mgorny, alekseyshl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D28417

llvm-svn: 291570

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