[clang] 2df77ac - [clang][X86] Add __cpuidex function to cpuid.h

[Aiden Grossman via cfe-commits]

Author: Aiden Grossman
Date: 2023-05-24T06:27:46Z
New Revision: 2df77ac20a1ed996706b164b0c4ed5ad140f635f

URL: https://github.com/llvm/llvm-project/commit/2df77ac20a1ed996706b164b0c4ed5ad140f635f
DIFF: https://github.com/llvm/llvm-project/commit/2df77ac20a1ed996706b164b0c4ed5ad140f635f.diff

LOG: [clang][X86] Add __cpuidex function to cpuid.h

MSVC has a `__cpuidex` function implemented to call the underlying cpuid
instruction which accepts a leaf, subleaf, and data array that the output
data is written into. This patch adds this functionality into clang
under the cpuid.h header. This also makes clang match GCC's behavior.
GCC has had `__cpuidex` in its cpuid.h since 2020.

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D150646

Added: 
    clang/test/Headers/__cpuidex_conflict.c

Modified: 
    clang/lib/Headers/cpuid.h
    clang/test/Headers/cpuid.c

Removed: 
    


################################################################################
diff  --git a/clang/lib/Headers/cpuid.h b/clang/lib/Headers/cpuid.h
index 1ad6853a97c9d..454f74e92f85a 100644
--- a/clang/lib/Headers/cpuid.h
+++ b/clang/lib/Headers/cpuid.h
@@ -328,4 +328,14 @@ static __inline int __get_cpuid_count (unsigned int __leaf,
     return 1;
 }
 
+// If MS extensions are enabled, __cpuidex is defined as a builtin which will
+// conflict with the __cpuidex definition below.
+#ifndef _MSC_EXTENSIONS
+static __inline void __cpuidex (int __cpu_info[4], int __leaf, int __subleaf)
+{
+  __cpuid_count(__leaf, __subleaf, __cpu_info[0], __cpu_info[1], __cpu_info[2],
+                __cpu_info[3]);
+}
+#endif
+
 #endif /* __CPUID_H */

diff  --git a/clang/test/Headers/__cpuidex_conflict.c b/clang/test/Headers/__cpuidex_conflict.c
new file mode 100644
index 0000000000000..0eff1ff425f83
--- /dev/null
+++ b/clang/test/Headers/__cpuidex_conflict.c
@@ -0,0 +1,15 @@
+// Make sure that __cpuidex in cpuid.h doesn't conflict with the MS
+// compatibility built in by ensuring compilation succeeds:
+// RUN: %clang_cc1 %s -ffreestanding -fms-extensions -fms-compatibility \
+// RUN:  -fms-compatibility-version=19.00 -triple x86_64-pc-windows-msvc -emit-llvm -o -
+
+typedef __SIZE_TYPE__ size_t;
+
+#include <intrin.h>
+#include <cpuid.h>
+
+int cpuid_info[4];
+
+void test_cpuidex(unsigned level, unsigned count) {
+  __cpuidex(cpuid_info, level, count);
+}

diff  --git a/clang/test/Headers/cpuid.c b/clang/test/Headers/cpuid.c
index 7e485495c1066..6ed12eca7a61d 100644
--- a/clang/test/Headers/cpuid.c
+++ b/clang/test/Headers/cpuid.c
@@ -6,14 +6,19 @@
 
 // CHECK-64: {{.*}} call { i32, i32, i32, i32 } asm "  xchgq  %rbx,${1:q}\0A cpuid\0A xchgq %rbx,${1:q}", "={ax},=r,={cx},={dx},0,~{dirflag},~{fpsr},~{flags}"(i32 %{{[a-z0-9]+}})
 // CHECK-64: {{.*}} call { i32, i32, i32, i32 } asm "  xchgq  %rbx,${1:q}\0A  cpuid\0A  xchgq  %rbx,${1:q}", "={ax},=r,={cx},={dx},0,2,~{dirflag},~{fpsr},~{flags}"(i32 %{{[a-z0-9]+}}, i32 %{{[a-z0-9]+}})
+// CHECK-64: {{.*}} call { i32, i32, i32, i32 } asm "  xchgq  %rbx,${1:q}\0A  cpuid\0A  xchgq  %rbx,${1:q}", "={ax},=r,={cx},={dx},0,2,~{dirflag},~{fpsr},~{flags}"(i32 %{{[a-z0-9]+}}, i32 %{{[a-z0-9]+}})
 
 // CHECK-32: {{.*}} call { i32, i32, i32, i32 } asm "cpuid", "={ax},={bx},={cx},={dx},0,~{dirflag},~{fpsr},~{flags}"(i32 %{{[a-z0-9]+}})
 // CHECK-32: {{.*}} call { i32, i32, i32, i32 } asm "cpuid", "={ax},={bx},={cx},={dx},0,2,~{dirflag},~{fpsr},~{flags}"(i32 %{{[a-z0-9]+}}, i32 %{{[a-z0-9]+}})
+// CHECK-32: {{.*}} call { i32, i32, i32, i32 } asm "cpuid", "={ax},={bx},={cx},={dx},0,2,~{dirflag},~{fpsr},~{flags}"(i32 %{{[a-z0-9]+}}, i32 %{{[a-z0-9]+}})
 
 unsigned eax0, ebx0, ecx0, edx0;
 unsigned eax1, ebx1, ecx1, edx1;
 
+int cpuid_info[4];
+
 void test_cpuid(unsigned level, unsigned count) {
   __cpuid(level, eax1, ebx1, ecx1, edx1);
   __cpuid_count(level, count, eax0, ebx0, ecx0, edx0);
+  __cpuidex(cpuid_info, level, count);
 }