[X86] Make `x86intrin.h`, `immintrin.h` includable with `-fno-gnu-inline-asm`.

[vsapsai]

Summary

Currently immintrin.h includes pconfigintrin.h and sgxintrin.h
which contain inline assembly. It causes failures when building with the
flag -fno-gnu-inline-asm.

Fix by excluding functions with inline assembly when this extension is
disabled. So far there was no need to support _pconfig_u32,
_enclu_u32, _encls_u32, _enclv_u32 on platforms that require
-fno-gnu-inline-asm. But if developers start using these functions,
they'll have compile-time undeclared identifier errors which is
preferrable to runtime errors.

rdar://problem/49540880

[rnk]

I see one more instance of unprotected asm usage, but it's under #ifdef _MSC_VER, it's the HLE extensions. Can you protect that, and then add another RUN line with a windows triple and -fms-extensions to test it?

[vsapsai]

• Improve -fno-gnu-inline-asm support for MS-compatibility too.

Didn't use -fms-compatibility in the test and it seems to be working fine.
Don't know if it is accidental and if I should add the flag.

[rnk]

lgtm, thanks!

In D61621#1496978, @vsapsai wrote:

Didn't use -fms-compatibility in the test and it seems to be working fine.
Don't know if it is accidental and if I should add the flag.

-fms-extensions is probably all you need. That's the one that defines _MSC_VER.

[vsapsai]

In D61621#1497027, @rnk wrote:

lgtm, thanks!

In D61621#1496978, @vsapsai wrote:

Didn't use -fms-compatibility in the test and it seems to be working fine.
Don't know if it is accidental and if I should add the flag.

-fms-extensions is probably all you need. That's the one that defines _MSC_VER.

Thanks for extra information and for the review. In my testing it was -fms-compatibility-version that defines _MSC_VER on macOS. I haven't tested extensively but looks like for the driver -fms-extensions should be enough but for -cc1 you need -fms-compatibility-version.

cfe/trunk/lib/Headers/immintrin.h

 #if !defined(_MSC_VER) || __has_feature(modules) || defined(__PTWRITE__)
 #include <ptwriteintrin.h>
 #endif
 
 #if !defined(_MSC_VER) || __has_feature(modules) || defined(__INVPCID__)
 #include <invpcidintrin.h>
 #endif
 
-#ifdef _MSC_VER
+#if defined(_MSC_VER) && __has_extension(gnu_asm)
 /* Define the default attributes for these intrinsics */
 #define __DEFAULT_FN_ATTRS __attribute__((__always_inline__, __nodebug__))
 #ifdef __cplusplus
 extern "C" {
 #endif
 /*----------------------------------------------------------------------------*\
 |* Interlocked Exchange HLE
 \*----------------------------------------------------------------------------*/

 }
 #endif
 #ifdef __cplusplus
 }
 #endif
 
 #undef __DEFAULT_FN_ATTRS
 
-#endif /* _MSC_VER */
+#endif /* defined(_MSC_VER) && __has_extension(gnu_asm) */
 
 #endif /* __IMMINTRIN_H */

cfe/trunk/lib/Headers/pconfigintrin.h

 #error "Never use <pconfigintrin.h> directly; include <x86intrin.h> instead."
 #endif
 
 #ifndef __PCONFIGINTRIN_H
 #define __PCONFIGINTRIN_H
 
 #define __PCONFIG_KEY_PROGRAM 0x00000001
 
+#if __has_extension(gnu_asm)
+
 /* Define the default attributes for the functions in this file. */
 #define __DEFAULT_FN_ATTRS \
   __attribute__((__always_inline__, __nodebug__,  __target__("pconfig")))
 
 static __inline unsigned int __DEFAULT_FN_ATTRS
 _pconfig_u32(unsigned int __leaf, __SIZE_TYPE__ __d[])
 {
   unsigned int __result;
   __asm__ ("pconfig"
            : "=a" (__result), "=b" (__d[0]), "=c" (__d[1]), "=d" (__d[2])
            : "a" (__leaf), "b" (__d[0]), "c" (__d[1]), "d" (__d[2])
            : "cc");
   return __result;
 }
 
 #undef __DEFAULT_FN_ATTRS
 
+#endif /* __has_extension(gnu_asm) */
+
 #endif

cfe/trunk/lib/Headers/sgxintrin.h

 /*===---- sgxintrin.h - X86 SGX intrinsics configuration -------------------===
  *
  * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
  * See https://llvm.org/LICENSE.txt for license information.
  * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  *
  *===-----------------------------------------------------------------------===
  */
 
 #if !defined __X86INTRIN_H && !defined __IMMINTRIN_H
 #error "Never use <sgxintrin.h> directly; include <x86intrin.h> instead."
 #endif
 
 #ifndef __SGXINTRIN_H
 #define __SGXINTRIN_H
 
+#if __has_extension(gnu_asm)
+
 /* Define the default attributes for the functions in this file. */
 #define __DEFAULT_FN_ATTRS \
   __attribute__((__always_inline__, __nodebug__,  __target__("sgx")))
 
 static __inline unsigned int __DEFAULT_FN_ATTRS
 _enclu_u32(unsigned int __leaf, __SIZE_TYPE__ __d[])
 {
   unsigned int __result;
__asm__ ("enclv"
            : "=a" (__result), "=b" (__d[0]), "=c" (__d[1]), "=d" (__d[2])
            : "a" (__leaf), "b" (__d[0]), "c" (__d[1]), "d" (__d[2])
            : "cc");
   return __result;
 }
 
 #undef __DEFAULT_FN_ATTRS
 
+#endif /* __has_extension(gnu_asm) */
+
 #endif

cfe/trunk/test/Modules/compiler_builtins_x86.c

 // RUN: rm -rf %t
 // RUN: %clang_cc1 -triple i686-unknown-unknown -fsyntax-only -fmodules -fimplicit-module-maps -fmodules-cache-path=%t %s -verify -ffreestanding
 // RUN: %clang_cc1 -triple i686-unknown-unknown -fsyntax-only -fmodules -fmodule-map-file=%resource_dir/module.modulemap -fmodules-cache-path=%t %s -verify -ffreestanding
+// RUN: %clang_cc1 -triple i686-unknown-unknown -fsyntax-only -fmodules -fimplicit-module-maps -fmodules-cache-path=%t %s -verify -ffreestanding -fno-gnu-inline-asm
+// RUN: %clang_cc1 -triple i686--windows -fsyntax-only -fmodules -fimplicit-module-maps -fmodules-cache-path=%t %s -verify -ffreestanding -fno-gnu-inline-asm -fms-extensions -fms-compatibility-version=17.00
 // expected-no-diagnostics
 
 #include<x86intrin.h>