If we split these features in the compiler (see relevant pull request
https://github.com/llvm/llvm-project/pull/109299), we would only be able
to hand-write a 'memtag2' version using inline assembly since the
compiler cannot generate the instructions that become available with
FEAT_MTE2. However these instructions only work at Exception Level 1, so
they would be unusable since FMV is a user space facility. I am
therefore unifying them.
Approved in ACLE as https://github.com/ARM-software/acle/pull/351
MSVC has a set of qualifiers to allow using 32-bit signed/unsigned
pointers when building 64-bit targets. This is useful for WoW code
(i.e., the part of Windows that handles running 32-bit application on a
64-bit OS). Currently this is supported on x64 using the 270, 271 and
272 address spaces, but does not work for AArch64 at all.
This change adds the same 270, 271 and 272 address spaces to AArch64 and
adjusts the data layout string accordingly. Clang will generate the
correct address space casts, but these will currently be ignored until
the AArch64 backend is updated to handle them.
Partially fixes#62536
This is a resurrected version of <https://reviews.llvm.org/D158857>
(originally created by @a_vorobev) - I've cleaned it up a little, fixed
the rest of the tests and added to auto-upgrade for the data layout.
When `pauthtest` is either passed as environment part of AArch64 Linux
triple
or passed via `-mabi=`, enable the following ptrauth flags:
- `intrinsics`;
- `calls`;
- `returns`;
- `auth-traps`;
- `vtable-pointer-address-discrimination`;
- `vtable-pointer-type-discrimination`;
- `init-fini`.
Some related stuff is still subject to change, and the ABI itself might
be changed, so end users are not expected to use this and the ABI name
has 'test' suffix.
If `-mabi=pauthtest` option is used, it's normalized to effective
triple.
When the environment part of the effective triple is `pauthtest`, try
to use `aarch64-linux-pauthtest` as multilib directory.
The following is not supported:
- combination of `pauthtest` ABI with any branch protection scheme
except BTI;
- explicit set of environment part of the triple to a value different
from `pauthtest` in combination with `-mabi=pauthtest`;
- usage on non-Linux OS.
---------
Co-authored-by: Anatoly Trosinenko <atrosinenko@accesssoftek.com>
The 2022 SME2.1and SVE2.1 feature macros are missing from Clang. Passing
'-target-feature +sve2p1' and 'target-feature +sme2p1' should prompt
Clang to define __ARM_FEATURE_SVE2p1 and __ARM_FEATURE_SME2p1
respectively, including their prerequisits..
This patch includes __ARM_FEATURE_SVE2p1 and __ARM_FEATURE_SME2p1, plus
a clang preprocessor test for each. It also ensures that the Clang macro
builder is used in a consistent fashion across Targets/AArch64.cpp.
The specification for SVE2.1 is documented in the latest (2024 Q1) ACLE
release: https://github.com/ARM-software/acle/releases . SME2p1 is not
yet featured in ACLE documentation but its features are described under
https://developer.arm.com/documentation/ddi0487/latest/
This is the second attempt. When parsing the target attribute
we should be letting cc1 features which don't correspond to
Extensions pass through to avoid errors like the following:
% cat neon.c
__attribute__((target("arch=armv8-a")))
uint64x2_t foo(uint64x2_t a, uint64x2_t b) { return veorq_u64(a, b); }
% clang --target=aarch64-linux-gnu -c neon.c
error: always_inline function 'veorq_u64' requires target feature
'outline-atomics', but would be inlined into function 'foo'
that is compiled without support for 'outline-atomics'
Co-authored-by: Tomas Matheson <Tomas.Matheson@arm.com>
This is a follow up to #92037, which moved the architecture information.
Generate the AArch64TargetParser CPUInfo from tablegen Processor defs using a
new tablegen emitter. Some basic error checking is added in the emitter to
ensure that duplicate features are not added to the Processor defs.
The generic CPU becomes an entry in tablegen.
Some CPU features which were present in the CPUInfo but absent from the tablegen
defs have been added to tablegen. FeatureCrypto is replaced with FeatureSHA2 and
FeatureAES. This changes a few of the tests.
This reverts commit 70510733af33c70ff7877eaf30d7718b9358a725.
The following code is now incorrectly rejected.
```
% cat neon.c
#include <arm_neon.h>
__attribute__((target("arch=armv8-a")))
uint64x2_t foo(uint64x2_t a, uint64x2_t b) {
return veorq_u64(a, b);
}
% newclang --target=aarch64-linux-gnu -c neon.c
neon.c:5:10: error: always_inline function 'veorq_u64' requires target feature 'outline-atomics', but would be inlined into function 'foo' that is compiled without support for 'outline-atomics'
5 | return veorq_u64(a, b);
| ^
1 error generated.
```
"+outline-atomics" seems misleading here.
My reverted attempt to decouple feature dependency expansion (see
#95056) made it evident that some features are still using the FMV
dependencies in the target attribute.
The original commit broke the llvm test suite. This was addressed here:
https://github.com/llvm/llvm-test-suite/pull/133. I am now relanding it.
This reverts commit 2cf14398c9341feddb419e7ff9c8c5623a3da3db since it
broke the llvm test suite:
SingleSource/UnitTests/AArch64/acle-fmv-features.c:59:9:
error: instruction requires: altnzcv
SingleSource/UnitTests/AArch64/acle-fmv-features.c:117:10:
error: instruction requires: aes
...
Looks like the FMV dependencies were used in the target attribute and
now features that are FMVOnly (have AEK_NONE) cannot be expanded in
parseTargetAttr using the ExtensionSet.
This suggests that either the tests are wrong (they are using an FMVOnly
feature in a target attribute), or that we need to turn the FMVOnly
features into Extensions (these two are tablegen classes).
The dependency expansion step which was introduced by FMV has been
erroneously used for non-FMV features, for example when parsing the
target attribute. The PR #93695 has rectified most of the tests which
were relying on dependency expansion of target features specified on the
-cc1 command line. In this patch I am decoupling the dependency
expansion of features specified on the target attribute from FMV.
To do that first I am expanding FMV dependencies before passing the list
of target features to initFeatureMap(). Similarly when parsing the
target attribute I am reconstructing an ExtensionSet from the list of
target features which was created during the command line option
parsing. The attribute parsing may toggle bits of that ExtensionSet and
at the end it is converted to a list of target features. Those are
passed to initFeatureMap(), which no longer requires an override.
A side effect of this refactoring is that features specified on the
target_version attribute now supersede the command line options, which
is what should be happening in the first place.
Adds AArch64 support for the `preserve_none` calling convention.
Registers X0-X7, X9-X15 and X19-X28 are caller save, and can be used to
pass arguments. Delegates to AAPCS for all other registers.
Closes#87423
Currently, LLVM enables `-mbranch-protection=standard` as `bti+pac-ret`.
To align LLVM with the behaviour in GNU, this has been updated to
`bti+pac-ret+pc` when FEAT_PAuth_LR is enabled as an optional feature
via the `-mcpu=` options. If this is not enabled, then this will revert
to the existing behaviour.
This patch makes determining alignment and width of BitInt to be target
ABI specific and makes it consistent with [Procedure Call Standard for
the Arm® 64-bit Architecture
(AArch64)](https://github.com/ARM-software/abi-aa/blob/main/aapcs64/aapcs64.rst)
for AArch64 targets.
This addresses an issue where the explicit alignment of 2 (for C++ ABI
reasons) was being propagated to the back end and causing under-aligned
functions (in special sections).
This is an alternate approach suggested by @efriedma-quic in PR #90415.
Fixes#90358
MSVC doesn't support generating __vectorcall calls in Arm64EC mode, but
it does treat it as a distinct type. The Microsoft STL depends on this
functionality. (Not sure if this is intentional.) Add support for
parsing the same way as MSVC, and add some checks to ensure we don't try
to actually generate code.
The error handling in CodeGen is ugly, but I can't think of a better way
to do it.
This is re-working of #74460, which adds a soft-float ABI for AArch64.
That was reverted because it causes errors when building the linux and
fuchsia kernels.
The problem is that GCC's implementation of the ABI compatibility checks
when using the hard-float ABI on a target without FP registers does it's
checks after optimisation. The previous version of this patch reported
errors for all uses of floating-point types, which is stricter than what
GCC does in practice.
This changes two things compared to the first version:
* Only check the types of function arguments and returns, not the types
of other values. This is more relaxed than GCC, while still guaranteeing
ABI compatibility.
* Move the check from Sema to CodeGen, so that inline functions are only
checked if they are actually used. There are some cases in the linux
kernel which depend on this behaviour of GCC.
This defines the basic set of pointer authentication clang builtins
(provided in a new header, ptrauth.h), with diagnostics and IRGen
support. The availability of the builtins is gated on a new flag,
`-fptrauth-intrinsics`.
Note that this only includes the basic intrinsics, and notably excludes
`ptrauth_sign_constant`, `ptrauth_type_discriminator`, and
`ptrauth_string_discriminator`, which need extra logic to be fully
supported.
This also introduces clang/docs/PointerAuthentication.rst, which
describes the ptrauth model in general, in addition to these builtins.
Co-Authored-By: Akira Hatanaka <ahatanaka@apple.com>
Co-Authored-By: John McCall <rjmccall@apple.com>
This reverts commit 89c1bf1230e011f2f0e43554c278205fa1819de5.
This has been unimplemenented for a while, and GCC does not implement
it, therefore we need to consider whether we should just deprecate it
in the ACLE instead.
This adds support for the AArch64 soft-float ABI. The specification for
this ABI was added by https://github.com/ARM-software/abi-aa/pull/232.
Because all existing AArch64 hardware has floating-point hardware, we
expect this to be a niche option, only used for embedded systems on
R-profile systems. We are going to document that SysV-like systems
should only ever use the base (hard-float) PCS variant:
https://github.com/ARM-software/abi-aa/pull/233. For that reason, I've
not added an option to select the ABI independently of the FPU hardware,
instead the new ABI is enabled iff the target architecture does not have
an FPU.
For testing, I have run this through an ABI fuzzer, but since this is
the first implementation it can only test for internal consistency
(callers and callees agree on the PCS), not for conformance to the ABI
spec.
This patch changes how the macro __ARM_ARCH is defined to match its
defintion in the ACLE. In ACLE 5.4.1, __ARM_ARCH is defined as equal to
the major architecture version for ISAs up to and including v8. From
v8.1 onwards, its definition is changed to include minor versions, such
that for an architecture vX.Y, __ARM_ARCH = X*100 + Y. Before this
patch, LLVM defined __ARM_ARCH using only the major architecture version
for all architecture versions. This patch adds functionality to define
__ARM_ARCH correctly for architectures greater than or equal to v8.1.
__ARM_STATE_ZA and __ARM_STATE_ZT0 are set when the compiler can parse
the "za" and "zt0" strings in the SME attributes.
__ARM_FEATURE_SME and __ARM_FEATURE_SME2 are set when the compiler can
generate code for attributes with "za" and "zt0" state, respectively.
__ARM_FEATURE_LOCALLY_STREAMING is set when the compiler supports the
__arm_locally_streaming attribute.
This enables specifing "za" or "zt0" to the clobber list for inline asm.
This complies with the acle SME addition to the asm extension here:
https://github.com/ARM-software/acle/pull/276
Add AEK_PAUTH to ARMV8_3A in TargetParser and let it propagate to
ARMV8R, as it aligns with GCC defaults.
After adding AEK_PAUTH, several tests from TargetParserTest.cpp crashed
when trying to format an error message, thus update a format string in
AssertSameExtensionFlags to account for bitmask being pre-formatted as
std::string.
The CHECK-PAUTH* lines in aarch64-target-features.c are updated to
account for the fact that FEAT_PAUTH support and pac-ret can be enabled
independently and all four combinations are possible.
This updates clang's target defines to include the ACLE changes covering
the FEAT_PAuth_LR architecture extension.
The changes include:
* The new `__ARM_FEATURE_PAUTH_LR` feature macro, which is set to 1 when
FEAT_PAuth_LR is available in the target.
* A new bit field for the existing `__ARM_FEATURE_PAC_DEFAULT` macro,
indicating the use of PC as a diversifier for Pointer Authentication
(from -mbranch-protection=pac-ret+pc).
The approved changes to the ACLE spec can be found here:
https://github.com/ARM-software/acle/pull/292
When this option is passed to clang, external (and/or weak) symbols
are not assumed to have the minimum ABI alignment normally required.
Symbols defined locally that are not weak are however still given the
minimum alignment.
This is implemented by passing a new parameter to getMinGlobalAlign()
named HasNonWeakDef that is used to return the right alignment value.
This is needed when external symbols created from a linker script may
not get the ABI minimum alignment and must therefore be treated as
unaligned by the compiler.
Currently there are several bits of code in the AArch64 driver which
attempt to enforce dependencies between optional features in the -march=
and -mcpu= options. However, these are based on the list of feature
names being enabled/disabled, so they have a lot of logic to consider
the order in which features were turned on and off, which doesn't scale
well as dependency chains get longer.
This patch moves the code handling these dependencies to TargetParser,
and changes them to use a Bitset of enabled features. This makes it easy
to check which features are enabled, and is converted back to a list of
LLVM feature names once all of the command-line options are parsed.
The motivating example for this was the -mcpu=cortex-r82+nofp option.
Previously, the code handling the dependency between the fp16 and
fp16fml extensions did not consider the nofp modifier, so it added
+fullfp16 to the feature list. This should have been disabled by the
+nofp modifier, and also the backend did follow the dependency between
fullfp16 and fp, resulting in fp being turned back on in the backend.
Most of the dependencies added to AArch64TargetParser.h weren't known
about by clang before, I built that list by checking what the backend
thinks the dependencies between SubtargetFeatures are.
-mbranch-protection=gcs (enabled by -mbranch-protection=standard) causes
generated objects to be marked with the gcs feature. This is done via
the guarded-control-stack module flag, in a similar way to
branch-target-enforcement and sign-return-address.
Enabling GCS causes the GNU_PROPERTY_AARCH64_FEATURE_1_GCS bit to be set
on generated objects. No code generation changes are required, as GCS
just requires that functions are called using BL and returned from using
RET (or other similar variant instructions), which is already the case.
- Adds a new +pc option to -mbranch-protection that will enable
the use of PC as a diversifier in PAC branch protection code.
- When +pauth-lr is enabled (-march=armv9.5a+pauth-lr) in combination
with -mbranch-protection=pac-ret+pc, the new 9.5-a instructions
(pacibsppc, retaasppc, etc) are used.
Documentation for the relevant instructions can be found here:
https://developer.arm.com/documentation/ddi0602/2023-09/Base-Instructions/
Co-authored-by: Lucas Prates <lucas.prates@arm.com>
This patch replaces uses of StringRef::{starts,ends}with with
StringRef::{starts,ends}_with for consistency with
std::{string,string_view}::{starts,ends}_with in C++20.
I'm planning to deprecate and eventually remove
StringRef::{starts,ends}with.
GCC sets `#define HAVE_atomic_compare_and_swapti 1` and therefore
defines `__GCC_HAVE_SYNC_COMPARE_AND_SWAP_16`.
Clang compiles the 16-byte legacy `__sync_bool_compare_and_swap` and new
`__atomic_compare_exchange` compile to LDXP/STXP or (with LSE)
CASP{,A,L,AL}.
Link: https://github.com/llvm/llvm-project/issues/71883
[LLVM][AArch64] Add ASM constraints for reduced GPR register ranges.
The patch adds the follow ASM constraints:
Uci => w8-w11/x8-x11
Ucj => w12-w15/x12-x15
These constraints are required for SME load/store instructions
where a reduced set of GPRs are used to specify ZA array vectors.
NOTE: GCC has agreed to use the same constraint syntax.
