Headers: Add ARM support to intrin.h for MSVC compatibility

This fixes compiling with headers from the Windows SDK for ARM, where the
YieldProcessor function (in winnt.h) refers to _ARM_BARRIER_ISHST.

The actual MSVC armintr.h contains a lot more definitions, but this is enough to
build code that uses the Windows SDK but doesn't use ARM intrinsics directly.

An alternative would to just keep the addition to intrin.h (to include
armintr.h), but not actually ship armintr.h, instead having clang's intrin.h
include armintr.h from MSVC's include directory. (That one works fine with
clang, at least for building code that uses the Windows SDK.)

Patch by Martin Storsjö!

llvm-svn: 277928

clang/lib/Headers/CMakeLists.txt

@@ -3,6 +3,7 @@ set(files
   altivec.h
   ammintrin.h
   arm_acle.h
+  armintr.h
   avx2intrin.h
   avx512bwintrin.h
   avx512cdintrin.h

clang/lib/Headers/armintr.h

@@ -0,0 +1,45 @@
+/*===---- armintr.h - ARM Windows intrinsics -------------------------------===
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ *===-----------------------------------------------------------------------===
+ */
+
+/* Only include this if we're compiling for the windows platform. */
+#ifndef _MSC_VER
+#include_next <armintr.h>
+#else
+
+#ifndef __ARMINTR_H
+#define __ARMINTR_H
+
+typedef enum
+{
+  _ARM_BARRIER_SY    = 0xF,
+  _ARM_BARRIER_ST    = 0xE,
+  _ARM_BARRIER_ISH   = 0xB,
+  _ARM_BARRIER_ISHST = 0xA,
+  _ARM_BARRIER_NSH   = 0x7,
+  _ARM_BARRIER_NSHST = 0x6,
+  _ARM_BARRIER_OSH   = 0x3,
+  _ARM_BARRIER_OSHST = 0x2
+} _ARMINTR_BARRIER_TYPE;
+
+#endif /* __ARMINTR_H */
+#endif /* _MSC_VER */

clang/lib/Headers/intrin.h

@@ -34,6 +34,10 @@
 #include <x86intrin.h>
 #endif
 
+#if defined(__arm__)
+#include <armintr.h>
+#endif
+
 /* For the definition of jmp_buf. */
 #if __STDC_HOSTED__
 #include <setjmp.h>

clang/test/Headers/ms-intrin.cpp

@@ -60,4 +60,8 @@ void f() {
   __readcr3();
   __writecr3(0);
 #endif
+
+#ifdef _M_ARM
+  __dmb(_ARM_BARRIER_ISHST);
+#endif
 }