From 122b06708722f075a2f7194e16f370dcf1dbd0c4 Mon Sep 17 00:00:00 2001
From: Guillaume Chatelet <gchatelet@google.com>
Date: Tue, 15 Jan 2019 15:18:08 +0100
Subject: [PATCH] Use Cmake macros to detect getauxval and dlopen

---
 CMakeLists.txt      | 15 ++++++++++++---
 src/hwcaps.c        | 23 ++++++-----------------
 test/CMakeLists.txt |  2 +-
 3 files changed, 19 insertions(+), 21 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index a5fbfc6..8150178 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -20,6 +20,12 @@ option(BUILD_SHARED_LIBS "Build library as shared." OFF)
 # library : cpu_features
 #
 
+include (CheckIncludeFile)
+include (CheckSymbolExists)
+
+check_symbol_exists(getauxval sys/auxv.h HAVE_STRONG_GETAUXVAL)
+check_include_file(dlfcn.h HAVE_DLFCN_H)
+
 set(_HDRS
   include/cpu_features_macros.h
 )
@@ -55,7 +61,7 @@ elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "^(powerpc|ppc)")
     list(APPEND _HDRS include/cpuinfo_ppc.h)
     list(APPEND _SRCS src/cpuinfo_ppc.c)
 else()
-  message(SEND_ERROR "Unsupported architectures ${CMAKE_SYSTEM_PROCESSOR}")
+  message(FATAL_ERROR "Unsupported architectures ${CMAKE_SYSTEM_PROCESSOR}")
 endif()
 
 add_library(cpu_features
@@ -71,8 +77,11 @@ target_include_directories(cpu_features
   include/internal
 )
 set_target_properties(cpu_features PROPERTIES PUBLIC_HEADER "${_HDRS}")
-target_compile_definitions(cpu_features
-  PUBLIC STACK_LINE_READER_BUFFER_SIZE=1024)
+target_compile_definitions(cpu_features PUBLIC
+  STACK_LINE_READER_BUFFER_SIZE=1024
+  HAVE_STRONG_GETAUXVAL=${HAVE_STRONG_GETAUXVAL}
+  HAVE_DLFCN_H=${HAVE_DLFCN_H}
+)
 target_link_libraries(cpu_features PUBLIC ${CMAKE_DL_LIBS})
 
 # The use of shared libraries is discouraged.
diff --git a/src/hwcaps.c b/src/hwcaps.c
index d8c6df2..815e5c1 100644
--- a/src/hwcaps.c
+++ b/src/hwcaps.c
@@ -31,22 +31,18 @@
   } while (0)
 #endif
 
-#if defined(CPU_FEATURES_ARCH_MIPS) || defined(CPU_FEATURES_ARCH_ANY_ARM)
-#define HWCAPS_ANDROID_MIPS_OR_ARM
-#endif
-
-#if defined(CPU_FEATURES_OS_LINUX_OR_ANDROID) && \
-    !defined(HWCAPS_ANDROID_MIPS_OR_ARM)
-#define HWCAPS_REGULAR_LINUX
-#endif
-
 ////////////////////////////////////////////////////////////////////////////////
 // Implementation of GetElfHwcapFromGetauxval
 ////////////////////////////////////////////////////////////////////////////////
 
 #if defined(CPU_FEATURES_MOCK_GET_ELF_HWCAP_FROM_GETAUXVAL)
 // Implementation will be provided by test/hwcaps_for_testing.cc.
-#elif defined(HWCAPS_ANDROID_MIPS_OR_ARM)
+#elif defined(HAVE_STRONG_GETAUXVAL)
+#include <sys/auxv.h>
+static unsigned long GetElfHwcapFromGetauxval(uint32_t hwcap_type) {
+  return getauxval(hwcap_type);
+}
+#elif defined(HAVE_DLFCN_H)
 // On Android we probe the system's C library for a 'getauxval' function and
 // call it if it exits, or return 0 for failure. This function is available
 // since API level 20.
@@ -91,13 +87,6 @@ static uint32_t GetElfHwcapFromGetauxval(uint32_t hwcap_type) {
   dlclose(libc_handle);
   return ret;
 }
-#elif defined(CPU_FEATURES_OS_LINUX_OR_ANDROID)
-// On Regular Linux we simply use getauxval.
-#include <dlfcn.h>
-#include <sys/auxv.h>
-static unsigned long GetElfHwcapFromGetauxval(uint32_t hwcap_type) {
-  return getauxval(hwcap_type);
-}
 #else
 #error "This platform does not provide hardware capabilities."
 #endif
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index b4e83f8..6f4a7cd 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -58,7 +58,7 @@ add_test(NAME linux_features_aggregator_test COMMAND linux_features_aggregator_t
 ## cpuinfo_x86_test
 if(CMAKE_SYSTEM_PROCESSOR STREQUAL "x86_64")
 add_executable(cpuinfo_x86_test cpuinfo_x86_test.cc ../src/cpuinfo_x86.c)
-target_compile_definitions(stack_line_reader PUBLIC CPU_FEATURES_MOCK_CPUID_X86)
+target_compile_definitions(cpuinfo_x86_test PUBLIC CPU_FEATURES_MOCK_CPUID_X86)
 target_link_libraries(cpuinfo_x86_test all_libraries)
 add_test(NAME cpuinfo_x86_test COMMAND cpuinfo_x86_test)
 endif()