Author: rnk Date: Wed Oct 16 20:29:48 2013 New Revision: 192860 URL: http://llvm.org/viewvc/llvm-project?rev=192860&view=rev Log: Add implementations of the MSVC barrier intrinsics
Summary: These are deprecated in VS 2012 according to MSDN. They don't actually compile down to any code. They prevent the compiler from reordering memory accesses across the barrier, which is what a memory-clobbering volatile asm does. Reviewers: echristo CC: cfe-commits Differential Revision: http://llvm-reviews.chandlerc.com/D1954 Modified: cfe/trunk/lib/Headers/Intrin.h cfe/trunk/test/Headers/ms-intrin.cpp Modified: cfe/trunk/lib/Headers/Intrin.h URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Headers/Intrin.h?rev=192860&r1=192859&r2=192860&view=diff ============================================================================== --- cfe/trunk/lib/Headers/Intrin.h (original) +++ cfe/trunk/lib/Headers/Intrin.h Wed Oct 16 20:29:48 2013 @@ -243,7 +243,9 @@ static __inline__ unsigned long __cdecl _lrotr(unsigned long, int); static __inline__ unsigned int _lzcnt_u32(unsigned int); +static __inline__ void _ReadBarrier(void); +static __inline__ void _ReadWriteBarrier(void); static __inline__ void *_ReturnAddress(void); @@ -280,6 +282,7 @@ unsigned int _t1mskc_u32(unsigned int); unsigned int _tzcnt_u32(unsigned int); unsigned int _tzcnt_u32(unsigned int); unsigned int _tzmsk_u32(unsigned int); +static __inline__ void _WriteBarrier(void); void _xabort(const unsigned int imm); unsigned __int32 xbegin(void); @@ -744,6 +747,24 @@ _InterlockedCompareExchange64(__int64 vo } #endif /*----------------------------------------------------------------------------*\ +|* Barriers +\*----------------------------------------------------------------------------*/ +static __inline__ void __attribute__((__always_inline__, __nodebug__)) +__attribute__((deprecated("use other intrinsics or C++11 atomics instead"))) +_ReadWriteBarrier(void) { + __asm__ volatile ("" : : : "memory"); +} +static __inline__ void __attribute__((__always_inline__, __nodebug__)) +__attribute__((deprecated("use other intrinsics or C++11 atomics instead"))) +_ReadBarrier(void) { + __asm__ volatile ("" : : : "memory"); +} +static __inline__ void __attribute__((__always_inline__, __nodebug__)) +__attribute__((deprecated("use other intrinsics or C++11 atomics instead"))) +_WriteBarrier(void) { + __asm__ volatile ("" : : : "memory"); +} +/*----------------------------------------------------------------------------*\ |* Misc \*----------------------------------------------------------------------------*/ static __inline__ void * __attribute__((__always_inline__, __nodebug__)) Modified: cfe/trunk/test/Headers/ms-intrin.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Headers/ms-intrin.cpp?rev=192860&r1=192859&r2=192860&view=diff ============================================================================== --- cfe/trunk/test/Headers/ms-intrin.cpp (original) +++ cfe/trunk/test/Headers/ms-intrin.cpp Wed Oct 16 20:29:48 2013 @@ -1,6 +1,6 @@ // RUN: %clang_cc1 -triple i386-pc-win32 -target-cpu pentium4 \ // RUN: -fms-extensions -fms-compatibility -fmsc-version=1700 \ -// RUN: -ffreestanding -fsyntax-only %s +// RUN: -ffreestanding -verify %s // Intrin.h needs size_t, but -ffreestanding prevents us from getting it from // stddef.h. Work around it with this typedef. @@ -11,3 +11,14 @@ typedef __SIZE_TYPE__ size_t; // Use some C++ to make sure we closed the extern "C" brackets. template <typename T> void foo(T V) {} + +void bar() { + _ReadWriteBarrier(); // expected-warning {{is deprecated: use other intrinsics or C++11 atomics instead}} + _ReadBarrier(); // expected-warning {{is deprecated: use other intrinsics or C++11 atomics instead}} + _WriteBarrier(); // expected-warning {{is deprecated: use other intrinsics or C++11 atomics instead}} + // FIXME: It'd be handy if we didn't have to hardcode the line number in + // intrin.h. + // [email protected]:754 {{declared here}} + // [email protected]:759 {{declared here}} + // [email protected]:764 {{declared here}} +} _______________________________________________ cfe-commits mailing list [email protected] http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
