From 34f552fae991a08065d4d5a2aff7a1bf3b3d0506 Mon Sep 17 00:00:00 2001
From: Andre Puschmann <andre@softwareradiosystems.com>
Date: Mon, 26 Nov 2018 18:16:34 +0100
Subject: [PATCH] add universal executable to select binary based on current
 ISA

- using cpuid to check x86 features
- using hwcap on ARM to check for NEON
---
 CMakeLists.txt                |   3 +-
 lib/src/common/CMakeLists.txt |   2 +
 lib/src/common/arch_select.cc | 104 ++++++++++++++++++++++++++++++++++
 3 files changed, 108 insertions(+), 1 deletion(-)
 create mode 100644 lib/src/common/arch_select.cc

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1d0f05568..f70f6d569 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -317,7 +317,8 @@ if(CMAKE_C_COMPILER_ID MATCHES "GNU" OR CMAKE_C_COMPILER_ID MATCHES "Clang")
   endif(NOT ${CMAKE_BUILD_TYPE} STREQUAL "Debug")
 
   if(${CMAKE_SYSTEM_PROCESSOR} MATCHES "arm")
-    set(CMAKE_C_FLAGS  "${CMAKE_C_FLAGS} -mfpu=neon -march=native -DIS_ARM -DHAVE_NEON")
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -mfpu=neon -march=native -DIS_ARM -DHAVE_NEON")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DIS_ARM")
     message(STATUS "have ARM")
     set(HAVE_NEON "True")
   else(${CMAKE_SYSTEM_PROCESSOR} MATCHES "arm")
diff --git a/lib/src/common/CMakeLists.txt b/lib/src/common/CMakeLists.txt
index 010f8f730..5e5bda2b0 100644
--- a/lib/src/common/CMakeLists.txt
+++ b/lib/src/common/CMakeLists.txt
@@ -25,6 +25,8 @@ add_library(srslte_common STATIC ${C_SOURCES} ${CXX_SOURCES})
 add_custom_target(gen_build_info COMMAND cmake -P ${CMAKE_BINARY_DIR}/SRSLTEbuildinfo.cmake)
 add_dependencies(srslte_common gen_build_info)
 
+add_executable(arch_select arch_select.cc)
+
 target_include_directories(srslte_common PUBLIC ${SEC_INCLUDE_DIRS})
 target_link_libraries(srslte_common ${SEC_LIBRARIES})
 install(TARGETS srslte_common DESTINATION ${LIBRARY_DIR})
diff --git a/lib/src/common/arch_select.cc b/lib/src/common/arch_select.cc
new file mode 100644
index 000000000..947b6501e
--- /dev/null
+++ b/lib/src/common/arch_select.cc
@@ -0,0 +1,104 @@
+/**
+ *
+ * \section COPYRIGHT
+ *
+ * Copyright 2013-2015 Software Radio Systems Limited
+ *
+ * \section LICENSE
+ *
+ * This file is part of the srsUE library.
+ *
+ * srsUE is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version.
+ *
+ * srsUE is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * A copy of the GNU Affero General Public License can be found in
+ * the LICENSE file in the top-level directory of this distribution
+ * and at http://www.gnu.org/licenses/.
+ *
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#ifdef IS_ARM
+#include <stdio.h>
+#include <sys/auxv.h>
+#include <asm/hwcap.h>
+#else
+#include <cpuid.h>
+#define X86_CPUID_BASIC_LEAF 1
+#define X86_CPUID_ADVANCED_LEAF 7
+#endif
+
+#define MAX_CMD_LEN (64)
+
+#ifndef IS_ARM
+const char* x86_get_isa()
+{
+  int ret = 0;
+  int has_sse42 = 0, has_avx = 0, has_avx2 = 0;
+  unsigned int eax = 0, ebx = 0, ecx = 0, edx = 0;
+
+  // query basic features
+  ret = __get_cpuid(X86_CPUID_BASIC_LEAF, &eax, &ebx, &ecx, &edx);
+  if (ret) {
+    has_sse42 = ecx & bit_SSE4_2;
+    has_avx = ecx & bit_AVX;
+  }
+
+  // query advanced features
+  ret = __get_cpuid_count(X86_CPUID_ADVANCED_LEAF, 0, &eax, &ebx, &ecx, &edx);
+  if (ret) {
+    has_avx2 = ebx & bit_AVX2;
+  }
+
+  if (has_avx2) {
+    return "avx2";
+  } else
+  if (has_avx) {
+    return "avx";
+  } else
+  if (has_sse42) {
+    return "sse4.2";
+  } else {
+    return "generic";
+  }
+}
+#endif
+
+#ifdef IS_ARM
+const char* arm_get_isa()
+{
+  if (getauxval(AT_HWCAP) & HWCAP_NEON) {
+    return "neon";
+  } else {
+    return "generic";
+  }
+}
+#endif
+
+int main(int argc, char *argv[])
+{
+  char cmd[MAX_CMD_LEN];
+#ifdef IS_ARM
+  snprintf(cmd, MAX_CMD_LEN, "%s-%s", argv[0], arm_get_isa());
+#else
+  snprintf(cmd, MAX_CMD_LEN, "%s-%s", argv[0], x86_get_isa());
+#endif
+
+  // execute command with same argument
+  if (execvp(cmd, &argv[0]) == -1) {
+    fprintf(stderr, "%s: %s\n", cmd, strerror(errno));
+    exit(errno);
+  }
+}
\ No newline at end of file