Revert "[builtins][arm64] Build __init_cpu_features_resolver on Apple platforms (#73685)"

And its follow up "fixup! [builtins][arm64] Build __init_cpu_features_resolver on Apple platforms (#73685)".

This reverts commit 5b47052 and
212a5e1.

Due to build failures on Windows:
```
C:\Users\Tcwg\llvm-worker\clang-arm64-windows-msvc-2stage\llvm\compiler-rt\lib\builtins\cpu_model.c(1571,2): error: No support for checking hwcap on this platform yet.
 1571 | #error No support for checking hwcap on this platform yet.
      |  ^
```
https://lab.llvm.org/buildbot/#/builders/120/builds/5990

Author: DavidSpickett

compiler-rt/lib/builtins/cpu_model.c

@@ -948,8 +948,6 @@ _Bool __aarch64_have_lse_atomics
 #if defined(__has_include)
 #if __has_include(<sys/auxv.h>)
 #include <sys/auxv.h>
-#define HAVE_SYS_AUXV
-#endif
 
 #if __has_include(<sys/ifunc.h>)
 #include <sys/ifunc.h>
@@ -963,8 +961,6 @@ typedef struct __ifunc_arg_t {
 
 #if __has_include(<asm/hwcap.h>)
 #include <asm/hwcap.h>
-#define HAVE_SYS_HWCAP
-#endif
 
 #if defined(__ANDROID__)
 #include <string.h>
@@ -1001,9 +997,6 @@ typedef struct __ifunc_arg_t {
 #ifndef HWCAP_SHA2
 #define HWCAP_SHA2 (1 << 6)
 #endif
-#ifndef HWCAP_CRC32
-#define HWCAP_CRC32 (1 << 7)
-#endif
 #ifndef HWCAP_ATOMICS
 #define HWCAP_ATOMICS (1 << 8)
 #endif
@@ -1156,7 +1149,6 @@ typedef struct __ifunc_arg_t {
   if (__system_property_get("ro.arch", arch) > 0 &&                            \
       strncmp(arch, "exynos9810", sizeof("exynos9810") - 1) == 0)
 
-#if !defined(__APPLE__)
 static void CONSTRUCTOR_ATTRIBUTE init_have_lse_atomics(void) {
 #if defined(__FreeBSD__)
   unsigned long hwcap;
@@ -1170,7 +1162,7 @@ static void CONSTRUCTOR_ATTRIBUTE init_have_lse_atomics(void) {
   zx_status_t status = _zx_system_get_features(ZX_FEATURE_KIND_CPU, &features);
   __aarch64_have_lse_atomics =
       status == ZX_OK && (features & ZX_ARM64_FEATURE_ISA_ATOMICS) != 0;
-#elif defined(HAVE_SYS_AUXV)
+#else
   unsigned long hwcap = getauxval(AT_HWCAP);
   _Bool result = (hwcap & HWCAP_ATOMICS) != 0;
 #if defined(__ANDROID__)
@@ -1188,11 +1180,8 @@ static void CONSTRUCTOR_ATTRIBUTE init_have_lse_atomics(void) {
   }
 #endif // defined(__ANDROID__)
   __aarch64_have_lse_atomics = result;
-#else
-#error No support for checking for lse atomics on this platfrom yet.
 #endif // defined(__FreeBSD__)
 }
-#endif // !defined(__APPLE__)
 
 #if !defined(DISABLE_AARCH64_FMV)
 // CPUFeatures must correspond to the same AArch64 features in
@@ -1270,76 +1259,6 @@ struct {
   // As features grows new fields could be added
 } __aarch64_cpu_features __attribute__((visibility("hidden"), nocommon));
 
-#if defined(__APPLE__)
-#include <TargetConditionals.h>
-#if TARGET_OS_OSX || TARGET_OS_IPHONE
-#include <dispatch/dispatch.h>
-#include <sys/sysctl.h>
-
-static bool isKnownAndSupported(const char *name) {
-  int32_t val = 0;
-  size_t size = sizeof(val);
-  if (sysctlbyname(name, &val, &size, NULL, 0))
-    return false;
-  return val;
-}
-
-void __init_cpu_features_resolver(void) {
-  // On Darwin platforms, this may be called concurrently by multiple threads
-  // because the resolvers that use it are called lazily at runtime (unlike on
-  // ELF platforms, where IFuncs are resolved serially at load time).  This
-  // function's effect on __aarch64_cpu_features should be idempotent, but even
-  // so we need dispatch_once to resolve the race condition.  Dispatch is
-  // available through libSystem, which we need anyway for the sysctl, so this
-  // does not add a new dependency.
-
-  static dispatch_once_t onceToken = 0;
-  dispatch_once(&onceToken, ^{
-    // https://developer.apple.com/documentation/kernel/1387446-sysctlbyname/determining_instruction_set_characteristics
-    static struct {
-      const char *sysctl_name;
-      enum CPUFeatures feature;
-    } features[] = {
-        {"hw.optional.arm.FEAT_FlagM", FEAT_FLAGM},
-        {"hw.optional.arm.FEAT_FlagM2", FEAT_FLAGM2},
-        {"hw.optional.arm.FEAT_FHM", FEAT_FP16FML},
-        {"hw.optional.arm.FEAT_DotProd", FEAT_DOTPROD},
-        {"hw.optional.arm.FEAT_RDM", FEAT_RDM},
-        {"hw.optional.arm.FEAT_LSE", FEAT_LSE},
-        {"hw.optional.floatingpoint", FEAT_FP},
-        {"hw.optional.AdvSIMD", FEAT_SIMD},
-        {"hw.optional.armv8_crc32", FEAT_CRC},
-        {"hw.optional.arm.FEAT_SHA1", FEAT_SHA1},
-        {"hw.optional.arm.FEAT_SHA256", FEAT_SHA2},
-        {"hw.optional.arm.FEAT_SHA3", FEAT_SHA3},
-        {"hw.optional.arm.FEAT_AES", FEAT_AES},
-        {"hw.optional.arm.FEAT_PMULL", FEAT_PMULL},
-        {"hw.optional.arm.FEAT_FP16", FEAT_FP16},
-        {"hw.optional.arm.FEAT_DIT", FEAT_DIT},
-        {"hw.optional.arm.FEAT_DPB", FEAT_DPB},
-        {"hw.optional.arm.FEAT_DPB2", FEAT_DPB2},
-        {"hw.optional.arm.FEAT_JSCVT", FEAT_JSCVT},
-        {"hw.optional.arm.FEAT_FCMA", FEAT_FCMA},
-        {"hw.optional.arm.FEAT_LRCPC", FEAT_RCPC},
-        {"hw.optional.arm.FEAT_LRCPC2", FEAT_RCPC2},
-        {"hw.optional.arm.FEAT_FRINTTS", FEAT_FRINTTS},
-        {"hw.optional.arm.FEAT_I8MM", FEAT_I8MM},
-        {"hw.optional.arm.FEAT_BF16", FEAT_BF16},
-        {"hw.optional.arm.FEAT_SB", FEAT_SB},
-        {"hw.optional.arm.FEAT_SPECRES", FEAT_PREDRES},
-        {"hw.optional.arm.FEAT_SSBS", FEAT_SSBS2},
-        {"hw.optional.arm.FEAT_BTI", FEAT_BTI},
-    };
-
-    for (size_t I = 0, E = sizeof(features) / sizeof(features[0]); I != E; ++I)
-      if (isKnownAndSupported(features[I].sysctl_name))
-        __aarch64_cpu_features.features |= (1ULL << features[I].feature);
-
-    __aarch64_cpu_features.features |= (1ULL << FEAT_INIT);
-  });
-}
-#endif // TARGET_OS_OSX || TARGET_OS_IPHONE
-#else  // defined(__APPLE__)
 static void __init_cpu_features_constructor(unsigned long hwcap,
                                             const __ifunc_arg_t *arg) {
 #define setCPUFeature(F) __aarch64_cpu_features.features |= 1ULL << F
@@ -1548,8 +1467,8 @@ void __init_cpu_features_resolver(unsigned long hwcap,
 }
 
 void CONSTRUCTOR_ATTRIBUTE __init_cpu_features(void) {
-  unsigned long hwcap = 0;
-  unsigned long hwcap2 = 0;
+  unsigned long hwcap;
+  unsigned long hwcap2;
   // CPU features already initialized.
   if (__aarch64_cpu_features.features)
     return;
@@ -1559,16 +1478,14 @@ void CONSTRUCTOR_ATTRIBUTE __init_cpu_features(void) {
   res |= elf_aux_info(AT_HWCAP2, &hwcap2, sizeof hwcap2);
   if (res)
     return;
-#elif defined(HAVE_SYS_AUXV)
+#else
 #if defined(__ANDROID__)
   // Don't set any CPU features,
   // detection could be wrong on Exynos 9810.
   IF_EXYNOS9810 return;
 #endif // defined(__ANDROID__)
   hwcap = getauxval(AT_HWCAP);
   hwcap2 = getauxval(AT_HWCAP2);
-#else
-#error No support for checking hwcap on this platform yet.
 #endif // defined(__FreeBSD__)
   __ifunc_arg_t arg;
   arg._size = sizeof(__ifunc_arg_t);
@@ -1580,7 +1497,8 @@ void CONSTRUCTOR_ATTRIBUTE __init_cpu_features(void) {
 #undef setCPUFeature
 #undef IF_EXYNOS9810
 }
-#endif // defined(__APPLE__)
 #endif // !defined(DISABLE_AARCH64_FMV)
 #endif // defined(__has_include)
+#endif // __has_include(<sys/auxv.h>)
+#endif // __has_include(<asm/hwcap.h>)
 #endif // defined(__aarch64__)