ports: Use memalign or _aligned_malloc, when available. Fallback to malloc

Using "_WIN32" to decide,
if the MSVC extensions _aligned_malloc / _aligned_free are available
is a bug that breaks other Compiler on Windows. (OpenWatcom as Example)

Regards ... Detlef

CMakeLists.txt

@@ -447,6 +447,9 @@ if(NOT HAVE_STRERROR)
 endif()
 set(CMAKE_REQUIRED_FLAGS)
 
+#
+# Check for aligned memory allocation support: POSIX
+#
 set(CMAKE_REQUIRED_DEFINITIONS -D_POSIX_C_SOURCE=200112L)
 set(CMAKE_REQUIRED_FLAGS "${ADDITIONAL_CHECK_FLAGS}")
 check_symbol_exists(posix_memalign stdlib.h HAVE_POSIX_MEMALIGN)
@@ -456,6 +459,9 @@ endif()
 set(CMAKE_REQUIRED_FLAGS)
 set(CMAKE_REQUIRED_DEFINITIONS)
 
+#
+# Check for aligned memory allocation support: C11
+#
 set(CMAKE_REQUIRED_DEFINITIONS -D_ISOC11_SOURCE=1)
 set(CMAKE_REQUIRED_FLAGS "${ADDITIONAL_CHECK_FLAGS}")
 check_symbol_exists(aligned_alloc stdlib.h HAVE_ALIGNED_ALLOC)
@@ -465,6 +471,28 @@ endif()
 set(CMAKE_REQUIRED_FLAGS)
 set(CMAKE_REQUIRED_DEFINITIONS)
 
+#
+# Check for aligned memory allocation support: GNU extension
+# Note: memalign() is deprecated in glibc
+#
+check_symbol_exists(memalign malloc.h HAVE_MEMALIGN)
+if(HAVE_MEMALIGN)
+    add_definitions(-DHAVE_MEMALIGN)
+endif()
+set(CMAKE_REQUIRED_DEFINITIONS)
+
+#
+# Check for aligned memory allocation support: MSVC extensions
+#
+check_symbol_exists(_aligned_malloc malloc.h HAVE__ALIGNED_MALLOC)
+if(HAVE__ALIGNED_MALLOC)
+    add_definitions(-DHAVE__ALIGNED_MALLOC)
+endif()
+set(CMAKE_REQUIRED_DEFINITIONS)
+
+#
+# Check whether a sanitizer was requested
+#
 if(WITH_SANITIZER STREQUAL "Address")
     add_address_sanitizer()
 elseif(WITH_SANITIZER STREQUAL "Memory")

configure

@@ -724,6 +724,8 @@ EOF
 fi
 echo >> configure.log
 
+
+# check for aligned memory allocation support: POSIX
 cat > $test.c <<EOF
 #define _POSIX_C_SOURCE 200112L
 #include <stdlib.h>
@@ -744,6 +746,7 @@ else
 fi
 echo >> configure.log
 
+# check for aligned memory allocation support: C11
 cat > $test.c <<EOF
 #define _ISOC11_SOURCE 1
 #include <stdlib.h>
@@ -763,6 +766,47 @@ else
 fi
 echo >> configure.log
 
+
+# check for aligned memory allocation support: GNU extension
+# Note: memalign() is deprecated in glibc
+cat > $test.c <<EOF
+#include <malloc.h>
+int main(void) {
+  void *ptr = memalign(64, 10);
+  if (ptr)
+    free(ptr);
+  return 0;
+}
+EOF
+if try $CC $CFLAGS -o $test $test.c $LDSHAREDLIBC; then
+  echo "Checking for memalign... Yes." | tee -a configure.log
+  CFLAGS="${CFLAGS} -DHAVE_MEMALIGN"
+  SFLAGS="${SFLAGS} -DHAVE_MEMALIGN"
+else
+  echo "Checking for memalign... No." | tee -a configure.log
+fi
+echo >> configure.log
+
+# check for aligned memory allocation support: MSVC extensions
+cat > $test.c <<EOF
+#include <malloc.h>
+int main(void) {
+  void *ptr = _aligned_malloc(10, 64);
+  if (ptr)
+    _aligned_free(ptr);
+  return 0;
+}
+EOF
+if try $CC $CFLAGS -o $test $test.c $LDSHAREDLIBC; then
+  echo "Checking for _aligned_malloc... Yes." | tee -a configure.log
+  CFLAGS="${CFLAGS} -DHAVE__ALIGNED_MALLOC"
+  SFLAGS="${SFLAGS} -DHAVE__ALIGNED_MALLOC"
+else
+  echo "Checking for _aligned_malloc... No." | tee -a configure.log
+fi
+echo >> configure.log
+
+
 # check for strerror() for use by gz* functions
 cat > $test.c <<EOF
 #include <string.h>

zutil_p.h

@@ -5,13 +5,16 @@
 #ifndef ZUTIL_P_H
 #define ZUTIL_P_H
 
-#if defined(__APPLE__) || defined(HAVE_POSIX_MEMALIGN) || defined(HAVE_ALIGNED_ALLOC)
+#if defined(HAVE_POSIX_MEMALIGN) || defined(HAVE_ALIGNED_ALLOC)
 #  include <stdlib.h>
 #elif defined(__FreeBSD__)
 #  include <stdlib.h>
 #  include <malloc_np.h>
-#else
+#elif defined(HAVE_MEMALIGN) || defined(HAVE__ALIGNED_MALLOC)
 #  include <malloc.h>
+#else
+/* Fallback, when no other aligned allocation function was found */
+#  include <stdlib.h>
 #endif
 
 /* Function to allocate 16 or 64-byte aligned memory */
@@ -23,20 +26,22 @@ static inline void *zng_alloc(size_t size) {
 #elif defined(HAVE_POSIX_MEMALIGN)
     void *ptr;
     return posix_memalign(&ptr, 64, size) ? NULL : ptr;
-#elif defined(_WIN32)
+#elif defined(HAVE__ALIGNED_MALLOC)
+    /* Fallback: Use MSVC extensions: _aligned_malloc() / _aligned_free() */
     return (void *)_aligned_malloc(size, 64);
-#elif defined(__APPLE__)
+#elif defined(HAVE_MEMALIGN)
-    /* Fallback for when posix_memalign and aligned_alloc are not available.
+    /* Fallback: Use deprecated GNU extension: memalign() */
-     * On macOS, it always aligns to 16 bytes. */
-    return (void *)malloc(size);
-#else
     return (void *)memalign(64, size);
+#else
+    /* Fallback: Use a normal allocation (On macOS, alignment is 16 bytes) */
+    /* zlib-ng adjust allocations for [de]compression to be properly aligned */
+    return (void *)malloc(size);
 #endif
 }
 
 /* Function that can free aligned memory */
 static inline void zng_free(void *ptr) {
-#if defined(_WIN32)
+#if defined(HAVE__ALIGNED_MALLOC) && !defined(HAVE_POSIX_MEMALIGN) && !defined(HAVE_ALIGNED_ALLOC)
     _aligned_free(ptr);
 #else
     free(ptr);