Add sodium_runtime_has_avx()

configure.ac

@@ -331,6 +331,19 @@ AS_IF([test "x$EMSCRIPTEN" = "x"],[
     [AC_MSG_RESULT(no)])
   CFLAGS="$oldcflags"
 
+  oldcflags="$CFLAGS"
+  AX_CHECK_COMPILE_FLAG([-mavx], [CFLAGS="$CFLAGS -mavx"])
+  AC_MSG_CHECKING(for AVX instructions set)
+  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
+#pragma GCC target("avx")
+#include <immintrin.h>
+]], [[ _mm256_zeroall(); ]])],
+    [AC_MSG_RESULT(yes)
+     AC_DEFINE([HAVE_AVXINTRIN_H], [1], [AVX is available])
+     AX_CHECK_COMPILE_FLAG([-mavx], [CFLAGS_AVX="-mavx"])],
+    [AC_MSG_RESULT(no)])
+  CFLAGS="$oldcflags"
+
   oldcflags="$CFLAGS"
   AX_CHECK_COMPILE_FLAG([-maes], [CFLAGS="$CFLAGS -maes"])
   AX_CHECK_COMPILE_FLAG([-mpclmul], [CFLAGS="$CFLAGS -mpclmul"])

src/libsodium/include/sodium/runtime.h

@@ -23,6 +23,9 @@ int sodium_runtime_has_ssse3(void);
 SODIUM_EXPORT
 int sodium_runtime_has_sse41(void);
 
+SODIUM_EXPORT
+int sodium_runtime_has_avx(void);
+
 SODIUM_EXPORT
 int sodium_runtime_has_pclmul(void);
 

src/libsodium/sodium/runtime.c

@@ -12,6 +12,7 @@ typedef struct CPUFeatures_ {
     int has_sse3;
     int has_ssse3;
     int has_sse41;
+    int has_avx;
     int has_pclmul;
     int has_aesni;
 } CPUFeatures;
@@ -22,6 +23,7 @@ static CPUFeatures _cpu_features;
 #define CPUIDECX_SSE3   0x00000001
 #define CPUIDECX_SSSE3  0x00000200
 #define CPUIDECX_SSE41  0x00080000
+#define CPUIDECX_AVX    0x10000000
 #define CPUIDECX_PCLMUL 0x00000002
 #define CPUIDECX_AESNI  0x02000000
 
@@ -124,6 +126,12 @@ _sodium_runtime_intel_cpu_features(CPUFeatures * const cpu_features)
     cpu_features->has_sse41 = ((cpu_info[2] & CPUIDECX_SSE41) != 0x0);
 #endif
 
+#ifndef HAVE_AVXINTRIN_H
+    cpu_features->has_avx = 0;
+#else
+    cpu_features->has_avx = ((cpu_info[2] & CPUIDECX_AVX) != 0x0);
+#endif
+
 #ifndef HAVE_WMMINTRIN_H
     cpu_features->has_pclmul = 0;
     cpu_features->has_aesni = 0;
@@ -172,6 +180,11 @@ sodium_runtime_has_sse41(void) {
     return _cpu_features.has_sse41;
 }
 
+int
+sodium_runtime_has_avx(void) {
+    return _cpu_features.has_avx;
+}
+
 int
 sodium_runtime_has_pclmul(void) {
     return _cpu_features.has_pclmul;