LLVM Clang error: definition of builtin function '__cpuid'

[ajkhoury]

Building on Ubuntu 22.10 with LLVM Clang 15 the following error occurs when attempting to compile linux/intrinsics.c:

SymCrypt/lib/linux/intrinsics.c:8:6: error: definition of builtin function '__cpuid'

Please consider adding a simple __has_builtin guard to linux/intrinsics.c in order to avoid redefining the cpuid intrinsics for compilers that support the cpuid intrinsics as builtins. Below is a patch:

diff --git lib/linux/intrinsics.c lib/linux/intrinsics.c
index 8670254..0935176 100644
--- lib/linux/intrinsics.c
+++ lib/linux/intrinsics.c
@@ -5,6 +5,12 @@
 // Copyright (c) Microsoft Corporation. Licensed under the MIT license.
 //

+#if !defined(__has_builtin)     // Optional of course.
+#define __has_builtin(x) 0      // Compatibility with non-clang compilers.
+#endif
+
+#if !__has_builtin(__cpuid)
+
 void __cpuid(int CPUInfo[4], int InfoType)
 {
     asm volatile ("cpuid"
@@ -12,9 +18,15 @@ void __cpuid(int CPUInfo[4], int InfoType)
         : "a" (InfoType));
 }

+#endif // !__has_builtin(__cpuid)
+
+#if !__has_builtin(__cpuidex)
+
 void __cpuidex(int CPUInfo[4], int InfoType, int ECXValue)
 {
     asm volatile ("cpuid"
         : "=a" (CPUInfo[0]), "=b" (CPUInfo[1]), "=c" (CPUInfo[2]), "=d" (CPUInfo[3])
         : "a" (InfoType), "c" (ECXValue));
 }
+
+#endif // !__has_builtin(__cpuidex)
\ No newline at end of file

[mlindgren]

Thanks for your report. This has been fixed internally and will be published with our next release.

[mlindgren]

We've now published the latest version which contains this fix. Sorry for the delay.