Author: agutowski Date: Fri Oct 14 12:33:05 2016 New Revision: 284253 URL: http://llvm.org/viewvc/llvm-project?rev=284253&view=rev Log: Implement __stosb intrinsic as a volatile memset
Summary: We need `__stosb` to be an intrinsic, because SecureZeroMemory function uses it without including intrin.h. Implementing it as a volatile memset is not consistent with MSDN specification, but it gives us target-independent IR while keeping the most important properties of `__stosb`. Reviewers: rnk, hans, thakis, majnemer Subscribers: cfe-commits Differential Revision: https://reviews.llvm.org/D25334 Modified: cfe/trunk/include/clang/Basic/BuiltinsX86.def cfe/trunk/lib/CodeGen/CGBuiltin.cpp cfe/trunk/lib/Headers/intrin.h cfe/trunk/test/CodeGen/ms-intrinsics.c cfe/trunk/test/Headers/ms-intrin.cpp Modified: cfe/trunk/include/clang/Basic/BuiltinsX86.def URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/BuiltinsX86.def?rev=284253&r1=284252&r2=284253&view=diff ============================================================================== --- cfe/trunk/include/clang/Basic/BuiltinsX86.def (original) +++ cfe/trunk/include/clang/Basic/BuiltinsX86.def Fri Oct 14 12:33:05 2016 @@ -2041,6 +2041,8 @@ TARGET_HEADER_BUILTIN(__emulu, "ULLiUiUi TARGET_HEADER_BUILTIN(_AddressOfReturnAddress, "v*", "nh", "intrin.h", ALL_MS_LANGUAGES, "") +TARGET_HEADER_BUILTIN(__stosb, "vUc*Ucz", "nh", "intrin.h", ALL_MS_LANGUAGES, "") + #undef BUILTIN #undef TARGET_BUILTIN #undef TARGET_HEADER_BUILTIN Modified: cfe/trunk/lib/CodeGen/CGBuiltin.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGBuiltin.cpp?rev=284253&r1=284252&r2=284253&view=diff ============================================================================== --- cfe/trunk/lib/CodeGen/CGBuiltin.cpp (original) +++ cfe/trunk/lib/CodeGen/CGBuiltin.cpp Fri Oct 14 12:33:05 2016 @@ -7770,6 +7770,11 @@ Value *CodeGenFunction::EmitX86BuiltinEx Value *F = CGM.getIntrinsic(Intrinsic::addressofreturnaddress); return Builder.CreateCall(F); } + case X86::BI__stosb: { + // We treat __stosb as a volatile memset - it may not generate "rep stosb" + // instruction, but it will create a memset that won't be optimized away. + return Builder.CreateMemSet(Ops[0], Ops[1], Ops[2], 1, true); + } } } Modified: cfe/trunk/lib/Headers/intrin.h URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Headers/intrin.h?rev=284253&r1=284252&r2=284253&view=diff ============================================================================== --- cfe/trunk/lib/Headers/intrin.h (original) +++ cfe/trunk/lib/Headers/intrin.h Fri Oct 14 12:33:05 2016 @@ -1024,11 +1024,6 @@ __movsw(unsigned short *__dst, unsigned : "%edi", "%esi", "%ecx"); } static __inline__ void __DEFAULT_FN_ATTRS -__stosb(unsigned char *__dst, unsigned char __x, size_t __n) { - __asm__("rep stosb" : : "D"(__dst), "a"(__x), "c"(__n) - : "%edi", "%ecx"); -} -static __inline__ void __DEFAULT_FN_ATTRS __stosd(unsigned long *__dst, unsigned long __x, size_t __n) { __asm__("rep stosl" : : "D"(__dst), "a"(__x), "c"(__n) : "%edi", "%ecx"); Modified: cfe/trunk/test/CodeGen/ms-intrinsics.c URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/ms-intrinsics.c?rev=284253&r1=284252&r2=284253&view=diff ============================================================================== --- cfe/trunk/test/CodeGen/ms-intrinsics.c (original) +++ cfe/trunk/test/CodeGen/ms-intrinsics.c Fri Oct 14 12:33:05 2016 @@ -14,6 +14,22 @@ typedef __SIZE_TYPE__ size_t; #include <intrin.h> +#if defined(__i386__) || defined(__x86_64__) +void test__stosb(unsigned char *Dest, unsigned char Data, size_t Count) { + return __stosb(Dest, Data, Count); +} + +// CHECK-I386: define{{.*}}void @test__stosb +// CHECK-I386: tail call void @llvm.memset.p0i8.i32(i8* %Dest, i8 %Data, i32 %Count, i32 1, i1 true) +// CHECK-I386: ret void +// CHECK-I386: } + +// CHECK-X64: define{{.*}}void @test__stosb +// CHECK-X64: tail call void @llvm.memset.p0i8.i64(i8* %Dest, i8 %Data, i64 %Count, i32 1, i1 true) +// CHECK-X64: ret void +// CHECK-X64: } +#endif + void *test_ReturnAddress() { return _ReturnAddress(); } Modified: cfe/trunk/test/Headers/ms-intrin.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Headers/ms-intrin.cpp?rev=284253&r1=284252&r2=284253&view=diff ============================================================================== --- cfe/trunk/test/Headers/ms-intrin.cpp (original) +++ cfe/trunk/test/Headers/ms-intrin.cpp Fri Oct 14 12:33:05 2016 @@ -38,7 +38,6 @@ void f() { __movsd(0, 0, 0); __movsw(0, 0, 0); - __stosb(0, 0, 0); __stosd(0, 0, 0); __stosw(0, 0, 0); _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits