Summary:
Libc++ currently implements the `ATOMIC_<TYPE>_LOCK_FREE` macros using the `__GCC_ATOMIC_<TYPE>_LOCK_FREE` macros. However these are not available when MSVC compatibility is enabled even though C11 `_Atomic` is. This prevents libc++ from correctly implementing `ATOMIC_<TYPE>_LOCK_FREE`.
This patch adds an alternative spelling `__CLANG_ATOMIC_<TYPE>_LOCK_FREE` that is enabled with `-fms-compatibility`.
Reviewers: rsmith, aaron.ballman, majnemer, zturner, compnerd, jfb, rnk
Reviewed By: rsmith
Subscribers: BillyONeal, smeenai, jfb, cfe-commits, dschuff
Differential Revision: https://reviews.llvm.org/D32265
llvm-svn: 300914
Correct the logic used to set ATOMIC_*_LOCK_FREE preprocessor macros not
to rely on the ABI alignment of types. Instead, just assume all those
types are aligned correctly by default since clang uses safe alignment
for _Atomic types even if the underlying types are aligned to a lower
boundary by default.
For example, the 'long long' and 'double' types on x86 are aligned to
32-bit boundary by default. However, '_Atomic long long' and '_Atomic
double' are aligned to 64-bit boundary, therefore satisfying
the requirements of lock-free atomic operations.
This fixes PR #19355 by correcting the value of
__GCC_ATOMIC_LLONG_LOCK_FREE on x86, and therefore also fixing
the assumption made in libc++ tests. This also fixes PR #30581 by
applying a consistent logic between the functions used to implement
both interfaces.
Differential Revision: https://reviews.llvm.org/D28213
llvm-svn: 291477
This commit teaches clang that is has to emit a warning when NULL is passed
as the 'expected' pointer parameter into an atomic compare exchange call.
rdar://18926650
Differential Revision: https://reviews.llvm.org/D26978
llvm-svn: 287776
Summary:
__atomic_load's allows it's first argument to be a pointer to a const type. However the second argument is an output parameter and must be a pointer to non-const.
This patch fixes the signature of __atomic_load generated by clang so that it respects the above requirements.
Reviewers: rsmith, majnemer
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D13420
llvm-svn: 264967
If there are two pointers passed to an atomic Builtin,
Clang doesn't allow the second (non-atomic) one to be qualified
with an address space.
Remove this restriction by recording the address space of passed pointers
in atomics type diagnostics.
llvm-svn: 256243
Diagnose when a pointer to const T is used as the first argument in at atomic
builtin unless that builtin is a load operation. This is already checked for
C11 atomics builtins but not for __atomic ones.
This patch was given the LGTM by rsmith when it was part
of a larger review. (See http://reviews.llvm.org/D10407)
llvm-svn: 249252
This test includes stdint.h, which might include system headers (and that might
not work, depending on the system configuration). Attempting to fix
llvm-clang-lld-x86_64-debian-fast.
llvm-svn: 218959
Adds a Clang-specific implementation of C11's stdatomic.h header. On systems,
such as FreeBSD, where a stdatomic.h header is already provided, we defer to
that header instead (using our __has_include_next technology). Otherwise, we
provide an implementation in terms of our __c11_atomic_* intrinsics (that were
created for this purpose).
C11 7.1.4p1 requires function declarations for atomic_thread_fence,
atomic_signal_fence, atomic_flag_test_and_set,
atomic_flag_test_and_set_explicit, and atomic_flag_clear, and requires that
they have external linkage. Accordingly, we provide these declarations, but if
a user elides the shadowing macros and uses them, then they must have a libc
(or similar) that actually provides definitions.
atomic_flag is implemented using _Bool as the underlying type. This is
consistent with the implementation provided by FreeBSD and also GCC 4.9 (at
least when __GCC_ATOMIC_TEST_AND_SET_TRUEVAL == 1).
Patch by Richard Smith (rebased and slightly edited by me -- Richard said I
should drive at this point).
llvm-svn: 218957
A few (mostly CodeGen) parts of Clang were tightly coupled to the
AArch64 backend. Now that it's gone, they will not even compile.
I've also deduplicated RUN lines in many of the AArch64 tests. This
might improve "make check-all" time noticably: some of those NEON
tests were monsters.
llvm-svn: 209578
Someone could write:
if (0) {
__c11_atomic_load(ptr, memory_order_release);
}
or the equivalent, which is perfectly valid, so we shouldn't outright reject
invalid orderings on purely static grounds.
rdar://problem/16242991
llvm-svn: 203564
This is a conservative check, because it's valid for the expression to be
non-constant, and in cases like that we just don't know whether it's valid.
rdar://problem/16242991
llvm-svn: 203561
This adds three overloaded intrinsics to Clang:
T __builtin_arm_ldrex(const volatile T *addr)
int __builtin_arm_strex(T val, volatile T *addr)
void __builtin_arm_clrex()
The intent is that these do what users would expect when given most sensible
types. Currently, "sensible" translates to ints, floats and pointers.
llvm-svn: 186394
This allows Clang to detect and deal wih __atomic_* operations properly on
AArch64. Previously we produced an error when encountering them at high
optimisation levels.
llvm-svn: 175438
__atomic_test_and_set, __atomic_clear, plus a pile of undocumented __GCC_*
predefined macros.
Implement library fallback for __atomic_is_lock_free and
__c11_atomic_is_lock_free, and implement __atomic_always_lock_free.
Contrary to their documentation, GCC's __atomic_fetch_add family don't
multiply the operand by sizeof(T) when operating on a pointer type.
libstdc++ relies on this quirk. Remove this handling for all but the
__c11_atomic_fetch_add and __c11_atomic_fetch_sub builtins.
Contrary to their documentation, __atomic_test_and_set and __atomic_clear
take a first argument of type 'volatile void *', not 'void *' or 'bool *',
and __atomic_is_lock_free and __atomic_always_lock_free have an argument
of type 'const volatile void *', not 'void *'.
With this change, libstdc++4.7's <atomic> passes libc++'s atomic test suite,
except for a couple of libstdc++ bugs and some cases where libc++'s test
suite tests for properties which implementations have latitude to vary.
llvm-svn: 154640
This is not quite sufficient for libstdc++'s <atomic>: we still need
__atomic_test_and_set and __atomic_clear, and may need a more complete
__atomic_is_lock_free implementation.
We are also missing an implementation of __atomic_always_lock_free,
__atomic_nand_fetch, and __atomic_fetch_nand, but those aren't needed
for libstdc++.
llvm-svn: 154579
<stdatomic.h> header.
In passing, fix LanguageExtensions to note that C11 and C++11 are no longer
"upcoming standards" but are now actually standardized.
llvm-svn: 154513
Eric Fiselier