[compiler-rt] b0e9842 - Revert "[FMV][AArch64] Add initial AT_HWCAP3 / AT_HWCAP4 support (#161595)" (#171071)

[via llvm-commits]

Author: Brad Smith
Date: 2025-12-07T22:32:37-05:00
New Revision: b0e98426f390c3f0d86c3a2c860a6d980a91e5de

URL: https://github.com/llvm/llvm-project/commit/b0e98426f390c3f0d86c3a2c860a6d980a91e5de
DIFF: https://github.com/llvm/llvm-project/commit/b0e98426f390c3f0d86c3a2c860a6d980a91e5de.diff

LOG: Revert "[FMV][AArch64] Add initial AT_HWCAP3 / AT_HWCAP4 support (#161595)" (#171071)

Crashing with older glibc.

This reverts commit edb43192516a55165cc4c158eb4fd4b2d81a8fce,
57b5ba00cb421b9be17bac10036763f42fbe9298 and
9715ccae1f98162f03ac0884a3dce5045b6b9a6e.

Added: 
    

Modified: 
    compiler-rt/lib/builtins/cpu_model/aarch64.c
    compiler-rt/lib/builtins/cpu_model/aarch64/fmv/android.inc
    compiler-rt/lib/builtins/cpu_model/aarch64/fmv/elf_aux_info.inc
    compiler-rt/lib/builtins/cpu_model/aarch64/fmv/getauxval.inc
    compiler-rt/lib/builtins/cpu_model/aarch64/hwcap.inc

Removed: 
    


################################################################################
diff  --git a/compiler-rt/lib/builtins/cpu_model/aarch64.c b/compiler-rt/lib/builtins/cpu_model/aarch64.c
index 06bc7c4a8190a..119d18b8df8d7 100644
--- a/compiler-rt/lib/builtins/cpu_model/aarch64.c
+++ b/compiler-rt/lib/builtins/cpu_model/aarch64.c
@@ -19,13 +19,15 @@
 #error This file is intended only for aarch64-based targets
 #endif
 
+#if __has_include(<sys/ifunc.h>)
+#include <sys/ifunc.h>
+#else
 typedef struct __ifunc_arg_t {
   unsigned long _size;
   unsigned long _hwcap;
   unsigned long _hwcap2;
-  unsigned long _hwcap3;
-  unsigned long _hwcap4;
 } __ifunc_arg_t;
+#endif // __has_include(<sys/ifunc.h>)
 
 // LSE support detection for out-of-line atomics
 // using HWCAP and Auxiliary vector

diff  --git a/compiler-rt/lib/builtins/cpu_model/aarch64/fmv/android.inc b/compiler-rt/lib/builtins/cpu_model/aarch64/fmv/android.inc
index d19beca690580..a9e3594e93c2d 100644
--- a/compiler-rt/lib/builtins/cpu_model/aarch64/fmv/android.inc
+++ b/compiler-rt/lib/builtins/cpu_model/aarch64/fmv/android.inc
@@ -27,14 +27,10 @@ void CONSTRUCTOR_ATTRIBUTE __init_cpu_features(void) {
 
   unsigned long hwcap = getauxval(AT_HWCAP);
   unsigned long hwcap2 = getauxval(AT_HWCAP2);
-  unsigned long hwcap3 = getauxval(AT_HWCAP3);
-  unsigned long hwcap4 = getauxval(AT_HWCAP4);
 
   __ifunc_arg_t arg;
   arg._size = sizeof(__ifunc_arg_t);
   arg._hwcap = hwcap;
   arg._hwcap2 = hwcap2;
-  arg._hwcap3 = hwcap3;
-  arg._hwcap4 = hwcap4;
   __init_cpu_features_constructor(hwcap | _IFUNC_ARG_HWCAP, &arg);
 }

diff  --git a/compiler-rt/lib/builtins/cpu_model/aarch64/fmv/elf_aux_info.inc b/compiler-rt/lib/builtins/cpu_model/aarch64/fmv/elf_aux_info.inc
index 1ada7b69de268..766338142a758 100644
--- a/compiler-rt/lib/builtins/cpu_model/aarch64/fmv/elf_aux_info.inc
+++ b/compiler-rt/lib/builtins/cpu_model/aarch64/fmv/elf_aux_info.inc
@@ -7,21 +7,17 @@ void __init_cpu_features_resolver(unsigned long hwcap,
 }
 
 void CONSTRUCTOR_ATTRIBUTE __init_cpu_features(void) {
-  unsigned long hwcap, hwcap2, hwcap3, hwcap4 = 0;
+  unsigned long hwcap, hwcap2 = 0;
   // CPU features already initialized.
   if (__atomic_load_n(&__aarch64_cpu_features.features, __ATOMIC_RELAXED))
     return;
 
   elf_aux_info(AT_HWCAP, &hwcap, sizeof hwcap);
   elf_aux_info(AT_HWCAP2, &hwcap2, sizeof hwcap2);
-  elf_aux_info(AT_HWCAP3, &hwcap3, sizeof hwcap3);
-  elf_aux_info(AT_HWCAP4, &hwcap4, sizeof hwcap4);
 
   __ifunc_arg_t arg;
   arg._size = sizeof(__ifunc_arg_t);
   arg._hwcap = hwcap;
   arg._hwcap2 = hwcap2;
-  arg._hwcap3 = hwcap3;
-  arg._hwcap4 = hwcap4;
   __init_cpu_features_constructor(hwcap | _IFUNC_ARG_HWCAP, &arg);
 }

diff  --git a/compiler-rt/lib/builtins/cpu_model/aarch64/fmv/getauxval.inc b/compiler-rt/lib/builtins/cpu_model/aarch64/fmv/getauxval.inc
index 6c52c5311bc53..486f77a1e4d2f 100644
--- a/compiler-rt/lib/builtins/cpu_model/aarch64/fmv/getauxval.inc
+++ b/compiler-rt/lib/builtins/cpu_model/aarch64/fmv/getauxval.inc
@@ -12,14 +12,10 @@ void CONSTRUCTOR_ATTRIBUTE __init_cpu_features(void) {
 
   unsigned long hwcap = getauxval(AT_HWCAP);
   unsigned long hwcap2 = getauxval(AT_HWCAP2);
-  unsigned long hwcap3 = getauxval(AT_HWCAP3);
-  unsigned long hwcap4 = getauxval(AT_HWCAP4);
 
   __ifunc_arg_t arg;
   arg._size = sizeof(__ifunc_arg_t);
   arg._hwcap = hwcap;
   arg._hwcap2 = hwcap2;
-  arg._hwcap3 = hwcap3;
-  arg._hwcap4 = hwcap4;
   __init_cpu_features_constructor(hwcap | _IFUNC_ARG_HWCAP, &arg);
 }

diff  --git a/compiler-rt/lib/builtins/cpu_model/aarch64/hwcap.inc b/compiler-rt/lib/builtins/cpu_model/aarch64/hwcap.inc
index 1c53191b84cf0..a77fde39de99e 100644
--- a/compiler-rt/lib/builtins/cpu_model/aarch64/hwcap.inc
+++ b/compiler-rt/lib/builtins/cpu_model/aarch64/hwcap.inc
@@ -2,7 +2,7 @@
 #define _IFUNC_ARG_HWCAP (1ULL << 62)
 #endif
 #ifndef AT_HWCAP
-#define AT_HWCAP 16 // Linux value
+#define AT_HWCAP 16
 #endif
 #ifndef HWCAP_CPUID
 #define HWCAP_CPUID (1 << 11)
@@ -90,7 +90,7 @@
 #endif
 
 #ifndef AT_HWCAP2
-#define AT_HWCAP2 26 // Linux value
+#define AT_HWCAP2 26
 #endif
 #ifndef HWCAP2_DCPODP
 #define HWCAP2_DCPODP (1 << 0)
@@ -185,19 +185,3 @@
 #ifndef HWCAP2_CSSC
 #define HWCAP2_CSSC (1UL << 34)
 #endif
-
-#ifndef AT_HWCAP3
-#ifdef __linux__
-#define AT_HWCAP3 29 // Linux value
-#else
-#define AT_HWCAP3 38 // BSD value
-#endif
-#endif
-
-#ifndef AT_HWCAP4
-#ifdef __linux__
-#define AT_HWCAP4 30 // Linux value
-#else
-#define AT_HWCAP4 39 // BSD value
-#endif
-#endif