[compiler-rt] 7dbbb5d - compiler-rt: Use FreeBSD's elf_aux_info to detect AArch64 HW features

[Dimitry Andric via llvm-commits]

Author: Dimitry Andric
Date: 2021-11-20T12:12:03+01:00
New Revision: 7dbbb5d3a46e1526cfa126ae02a5856d7ce0fda9

URL: https://github.com/llvm/llvm-project/commit/7dbbb5d3a46e1526cfa126ae02a5856d7ce0fda9
DIFF: https://github.com/llvm/llvm-project/commit/7dbbb5d3a46e1526cfa126ae02a5856d7ce0fda9.diff

LOG: compiler-rt: Use FreeBSD's elf_aux_info to detect AArch64 HW features

Using the out-of-line LSE atomics helpers for AArch64 on FreeBSD also
requires adding support for initializing __aarch64_have_lse_atomics
correctly. On Linux this is done with getauxval(3), on FreeBSD with
elf_aux_info(3), which has a slightly different interface.

Differential Revision: https://reviews.llvm.org/D109330

Added: 
    

Modified: 
    compiler-rt/lib/builtins/cpu_model.c

Removed: 
    


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diff  --git a/compiler-rt/lib/builtins/cpu_model.c b/compiler-rt/lib/builtins/cpu_model.c
index b8d807ed651c9..53e2d89708dcb 100644
--- a/compiler-rt/lib/builtins/cpu_model.c
+++ b/compiler-rt/lib/builtins/cpu_model.c
@@ -799,8 +799,14 @@ _Bool __aarch64_have_lse_atomics
 #define HWCAP_ATOMICS (1 << 8)
 #endif
 static void CONSTRUCTOR_ATTRIBUTE init_have_lse_atomics(void) {
+#if defined(__FreeBSD__)
+  unsigned long hwcap;
+  int result = elf_aux_info(AT_HWCAP, &hwcap, sizeof hwcap);
+  __aarch64_have_lse_atomics = result == 0 && (hwcap & HWCAP_ATOMICS) != 0;
+#else
   unsigned long hwcap = getauxval(AT_HWCAP);
   __aarch64_have_lse_atomics = (hwcap & HWCAP_ATOMICS) != 0;
+#endif
 }
 #endif // defined(__has_include)
 #endif // __has_include(<sys/auxv.h>)