From 639f0f665b4346d287014adc99e14a8497aadf18 Mon Sep 17 00:00:00 2001
From: Pablo Marquez Tello <pablo.tello@arm.com>
Date: Fri, 21 Jan 2022 15:25:27 +0000
Subject: Fix CPU detection code on Macos

* Query the number of cpus on the system via sysctl and set
  CpuInfo accordingly

* Query support for fp16 via sysctlbyname and use this to update
  isainfo

* Resolves MLCE-746

Change-Id: I4ad802435c21ee238bff0344af1d7a1ce2479ac5
Signed-off-by: Pablo Marquez Tello <pablo.tello@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/6989
Reviewed-by: Gunes Bayir <gunes.bayir@arm.com>
Reviewed-by: SiCong Li <sicong.li@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
---
 src/common/cpuinfo/CpuInfo.cpp | 34 +++++++++++++++++++++++++++++-----
 1 file changed, 29 insertions(+), 5 deletions(-)

diff --git a/src/common/cpuinfo/CpuInfo.cpp b/src/common/cpuinfo/CpuInfo.cpp
index 32504acc44..b96e108af5 100644
--- a/src/common/cpuinfo/CpuInfo.cpp
+++ b/src/common/cpuinfo/CpuInfo.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021 Arm Limited.
+ * Copyright (c) 2021-2022 Arm Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -43,6 +43,9 @@
 #if !defined(BARE_METAL) && !defined(__APPLE__) && (defined(__arm__) || defined(__aarch64__))
 #include <asm/hwcap.h> /* Get HWCAP bits from asm/hwcap.h */
 #include <sys/auxv.h>
+#elif defined(__APPLE__) && defined(__aarch64__)
+#include <sys/sysctl.h>
+#include <sys/types.h>
 #endif /* !defined(BARE_METAL) && !defined(__APPLE__) && (defined(__arm__) || defined(__aarch64__)) */
 
 #define ARM_COMPUTE_CPU_FEATURE_HWCAP_CPUID (1 << 11)
@@ -258,7 +261,19 @@ int get_max_cpus()
     }
     return max_cpus;
 }
-#endif /* !defined(BARE_METAL) && !defined(__APPLE__) && (defined(__arm__) || defined(__aarch64__)) */
+#elif  defined(__aarch64__) && defined(__APPLE__) /* !defined(BARE_METAL) && !defined(__APPLE__) && (defined(__arm__) || defined(__aarch64__)) */
+/** Query features through sysctlbyname
+  *
+  * @return int value queried
+  */
+int get_hw_capability(const std::string& cap)
+{
+     int64_t result(0);
+     size_t size = sizeof(result);
+     sysctlbyname(cap.c_str(), &result, &size, NULL, 0);
+     return result;
+}
+#endif /* defined(__aarch64__) && defined(__APPLE__) */
 
 #if defined(BARE_METAL) && defined(__aarch64__)
 uint64_t get_sve_feature_reg()
@@ -330,10 +345,19 @@ CpuInfo CpuInfo::build()
     std::vector<CpuModel> cpus_model(1, midr_to_model(midr));
     CpuInfo               info(isa, cpus_model);
     return info;
-#else                                     /* #elif(BARE_METAL) && defined(__aarch64__)  */
+#elif defined(__aarch64__) && defined(__APPLE__) /* #elif(BARE_METAL) && defined(__aarch64__) */
+    int ncpus = get_hw_capability("hw.logicalcpu");
+    CpuIsaInfo isainfo;
+    std::vector<CpuModel> cpus_model(ncpus);
+    isainfo.neon = get_hw_capability("hw.optional.neon");
+    isainfo.fp16 = get_hw_capability("hw.optional.neon_fp16");
+    isainfo.dot =  get_hw_capability("hw.optional.arm.FEAT_DotProd");
+    CpuInfo info(isainfo,cpus_model);
+    return info;
+#else  /* #elif defined(__aarch64__) && defined(__APPLE__) */
     CpuInfo info(CpuIsaInfo(), { CpuModel::GENERIC });
     return info;
-#endif                                    /* !defined(BARE_METAL) && !defined(__APPLE__) && (defined(__arm__) || defined(__aarch64__)) */
+#endif /* !defined(BARE_METAL) && !defined(__APPLE__) && (defined(__arm__) || defined(__aarch64__)) */
 }
 
 CpuModel CpuInfo::cpu_model(uint32_t cpuid) const
@@ -415,4 +439,4 @@ uint32_t num_threads_hint()
     return num_threads_hint;
 }
 } // namespace cpuinfo
-} // namespace arm_compute
\ No newline at end of file
+} // namespace arm_compute
-- 
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