This was reverted in r296063 due to PR31864.
On Mon, Jan 9, 2017 at 12:54 PM, Michal Gorny via cfe-commits <cfe-commits@lists.llvm.org> wrote: > Author: mgorny > Date: Mon Jan 9 14:54:20 2017 > New Revision: 291477 > > URL: http://llvm.org/viewvc/llvm-project?rev=291477&view=rev > Log: > [Frontend] Correct values of ATOMIC_*_LOCK_FREE to match builtin > > 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 > > Modified: > cfe/trunk/lib/Frontend/InitPreprocessor.cpp > cfe/trunk/test/Sema/atomic-ops.c > > Modified: cfe/trunk/lib/Frontend/InitPreprocessor.cpp > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Frontend/InitPreprocessor.cpp?rev=291477&r1=291476&r2=291477&view=diff > ============================================================================== > --- cfe/trunk/lib/Frontend/InitPreprocessor.cpp (original) > +++ cfe/trunk/lib/Frontend/InitPreprocessor.cpp Mon Jan 9 14:54:20 2017 > @@ -286,12 +286,12 @@ static void DefineFastIntType(unsigned T > > /// Get the value the ATOMIC_*_LOCK_FREE macro should have for a type with > /// the specified properties. > -static const char *getLockFreeValue(unsigned TypeWidth, unsigned TypeAlign, > - unsigned InlineWidth) { > +static const char *getLockFreeValue(unsigned TypeWidth, unsigned > InlineWidth) { > // Fully-aligned, power-of-2 sizes no larger than the inline > // width will be inlined as lock-free operations. > - if (TypeWidth == TypeAlign && (TypeWidth & (TypeWidth - 1)) == 0 && > - TypeWidth <= InlineWidth) > + // Note: we do not need to check alignment since _Atomic(T) is always > + // appropriately-aligned in clang. > + if ((TypeWidth & (TypeWidth - 1)) == 0 && TypeWidth <= InlineWidth) > return "2"; // "always lock free" > // We cannot be certain what operations the lib calls might be > // able to implement as lock-free on future processors. > @@ -881,7 +881,6 @@ static void InitializePredefinedMacros(c > #define DEFINE_LOCK_FREE_MACRO(TYPE, Type) \ > Builder.defineMacro("__GCC_ATOMIC_" #TYPE "_LOCK_FREE", \ > getLockFreeValue(TI.get##Type##Width(), \ > - TI.get##Type##Align(), \ > InlineWidthBits)); > DEFINE_LOCK_FREE_MACRO(BOOL, Bool); > DEFINE_LOCK_FREE_MACRO(CHAR, Char); > @@ -894,7 +893,6 @@ static void InitializePredefinedMacros(c > DEFINE_LOCK_FREE_MACRO(LLONG, LongLong); > Builder.defineMacro("__GCC_ATOMIC_POINTER_LOCK_FREE", > getLockFreeValue(TI.getPointerWidth(0), > - TI.getPointerAlign(0), > InlineWidthBits)); > #undef DEFINE_LOCK_FREE_MACRO > } > > Modified: cfe/trunk/test/Sema/atomic-ops.c > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/atomic-ops.c?rev=291477&r1=291476&r2=291477&view=diff > ============================================================================== > --- cfe/trunk/test/Sema/atomic-ops.c (original) > +++ cfe/trunk/test/Sema/atomic-ops.c Mon Jan 9 14:54:20 2017 > @@ -14,11 +14,7 @@ _Static_assert(__GCC_ATOMIC_WCHAR_T_LOCK > _Static_assert(__GCC_ATOMIC_SHORT_LOCK_FREE == 2, ""); > _Static_assert(__GCC_ATOMIC_INT_LOCK_FREE == 2, ""); > _Static_assert(__GCC_ATOMIC_LONG_LOCK_FREE == 2, ""); > -#ifdef __i386__ > -_Static_assert(__GCC_ATOMIC_LLONG_LOCK_FREE == 1, ""); > -#else > _Static_assert(__GCC_ATOMIC_LLONG_LOCK_FREE == 2, ""); > -#endif > _Static_assert(__GCC_ATOMIC_POINTER_LOCK_FREE == 2, ""); > > _Static_assert(__c11_atomic_is_lock_free(1), ""); > > > _______________________________________________ > cfe-commits mailing list > cfe-commits@lists.llvm.org > http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
