Use Use C11 aligned_alloc

See https://github.com/gnuradio/volk/pull/334

src/algorithms/libs/volk_gnsssdr_module/volk_gnsssdr/CMakeLists.txt

@@ -249,7 +249,24 @@ if(NOT ${FILESYSTEM_FOUND})
     endif()
 endif()
 
-# Orc
+
+########################################################################
+# check for aligned_alloc, since some compilers lack this C11 feature.
+# For Apple-clang use `posix_memalign`
+# For MSVC use `_aligned_malloc`.
+########################################################################
+include(CheckSymbolExists)
+if(NOT (${CMAKE_SYSTEM_NAME} MATCHES "Darwin"))
+    check_symbol_exists(aligned_alloc stdlib.h USE_ALIGNED_ALLOC)
+endif()
+if(NOT USE_ALIGNED_ALLOC)
+    check_symbol_exists(posix_memalign stdlib.h HAVE_POSIX_MEMALIGN)
+endif()
+
+
+########################################################################
+# Check if Orc is available
+########################################################################
 option(ENABLE_ORC "Enable Orc" TRUE)
 if(ENABLE_ORC)
     find_package(ORC)

src/algorithms/libs/volk_gnsssdr_module/volk_gnsssdr/apps/CMakeLists.txt

@@ -17,7 +17,6 @@ else()
     set(orc_lib "")
 endif()
 
-
 # allow 'large' files in 32 bit builds
 if(UNIX)
     add_definitions(-D_LARGEFILE_SOURCE
@@ -26,6 +25,11 @@ if(UNIX)
     )
 endif()
 
+# POSIX_MEMALIGN: If we have to fall back to `posix_memalign`.
+if(HAVE_POSIX_MEMALIGN)
+    message(STATUS "Use `posix_memalign` for aligned malloc!")
+    add_definitions(-DHAVE_POSIX_MEMALIGN)
+endif(HAVE_POSIX_MEMALIGN)
 
 # MAKE volk_gnsssdr_profile
 add_executable(volk_gnsssdr_profile

src/algorithms/libs/volk_gnsssdr_module/volk_gnsssdr/apps/volk_gnsssdr-config-info.cc

@@ -28,12 +28,12 @@ void print_malloc()
     // You don't want to change the volk_malloc code, so just copy the if/else
     // structure from there and give an explanation for the implementations
     std::cout << "Used malloc implementation: ";
-#if _POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600 || HAVE_POSIX_MEMALIGN
+#if HAVE_POSIX_MEMALIGN
     std::cout << "posix_memalign" << std::endl;
-#elif _MSC_VER >= 1400
+#elif defined(_MSC_VER)
-    std::cout << "aligned_malloc" << std::endl;
+    std::cout << "_aligned_malloc" << std::endl;
 #else
-    std::cout << "No standard handler available, using own implementation." << std::endl;
+    std::cout << "C11 aligned_alloc." << std::endl;
 #endif
 }
 

src/algorithms/libs/volk_gnsssdr_module/volk_gnsssdr/include/volk_gnsssdr/volk_gnsssdr_malloc.h

@@ -25,22 +25,20 @@ __VOLK_DECL_BEGIN
  * \brief Allocate \p size bytes of data aligned to \p alignment.
  *
  * \details
- * Because we don't have a standard method to allocate buffers in
+ * We use C11 and want to rely on C11 library features,
- * memory that are guaranteed to be on an alignment, VOLK handles this
+ * namely we use `aligned_alloc` to allocate aligned memory.
- * itself. The volk_gnsssdr_malloc function behaves like malloc in that it
+ * see: https://en.cppreference.com/w/c/memory/aligned_alloc
- * returns a pointer to the allocated memory. However, it also takes
- * in an alignment specification, which is usually something like 16 or
- * 32 to ensure that the aligned memory is located on a particular
- * byte boundary for use with SIMD.
  *
- * Internally, the volk_gnsssdr_malloc first checks if the compiler is C11
+ * Not all platforms support this feature.
- * compliant and uses the new aligned_alloc method. If not, it checks
+ * For Apple Clang, we fall back to `posix_memalign`.
- * if the system is POSIX compliant and uses posix_memalign. If that
+ * see: https://linux.die.net/man/3/aligned_alloc
- * fails, volk_gnsssdr_malloc handles the memory allocation and alignment
+ * For MSVC, we fall back to `_aligned_malloc`.
- * internally.
+ * see: https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/aligned-malloc?view=vs-2019
  *
  * Because of the ways in which volk_gnsssdr_malloc may allocate memory, it is
  * important to always free volk_gnsssdr_malloc pointers using volk_gnsssdr_free.
+ * Mainly, in case MSVC is used. Consult corresponding documentation
+ * in case you use MSVC.
  *
  * \param size The number of bytes to allocate.
  * \param alignment The byte alignment of the allocated memory.
@@ -50,7 +48,13 @@ VOLK_API void *volk_gnsssdr_malloc(size_t size, size_t alignment);
 
 /*!
  * \brief Free's memory allocated by volk_gnsssdr_malloc.
- * \param aptr The aligned pointer allocaed by volk_gnsssdr_malloc.
+ *
+ * \details
+ * We rely on C11 syntax and compilers and just call `free`
+ * on memory that was allocated with `aligned_alloc`.
+ * Thus, `volk_gnsssdr_free` inherits the same behavoir `free` exhibits.
+ *
+ * \param aptr The aligned pointer allocated by volk_gnsssdr_malloc.
  */
 VOLK_API void volk_gnsssdr_free(void *aptr);
 

src/algorithms/libs/volk_gnsssdr_module/volk_gnsssdr/lib/CMakeLists.txt

@@ -60,21 +60,14 @@ if(COMPILER_NAME MATCHES "GNU")
 endif()
 
 ########################################################################
-# check for posix_memalign, since some OSs do not internally define
+# POSIX_MEMALIGN: If we have to fall back to `posix_memalign`,
-# _XOPEN_SOURCE or _POSIX_C_SOURCE; they leave this to the user.
+# make it known to the compiler.
 ########################################################################
-
-include(CheckSymbolExists)
-check_symbol_exists(posix_memalign stdlib.h HAVE_POSIX_MEMALIGN)
-
 if(HAVE_POSIX_MEMALIGN)
+    message(STATUS "Use `posix_memalign` for aligned malloc!")
     add_definitions(-DHAVE_POSIX_MEMALIGN)
 endif()
 
-if(NOT DEFINED _XOPEN_SOURCE AND NOT MSVC)
-    add_definitions(-D_XOPEN_SOURCE=700)
-endif()
-
 ########################################################################
 # detect x86 flavor of CPU
 ########################################################################

src/algorithms/libs/volk_gnsssdr_module/volk_gnsssdr/lib/volk_gnsssdr_malloc.c

@@ -14,107 +14,62 @@
 #include <string.h>
 
 /*
- * For #defines used to determine support for allocation functions,
+ * C11 features:
- * see: http://linux.die.net/man/3/aligned_alloc
+ * see: https://en.cppreference.com/w/c/memory/aligned_alloc
+ *
+ * MSVC is broken
+ * see: https://docs.microsoft.com/en-us/cpp/overview/visual-cpp-language-conformance?view=vs-2019
+ * This section:
+ * C11 The Universal CRT implemented the parts of the
+ * C11 Standard Library that are required by C++17,
+ * with the exception of C99 strftime() E/O alternative
+ * conversion specifiers, C11 fopen() exclusive mode,
+ * and C11 aligned_alloc(). The latter is unlikely to
+ * be implemented, because C11 specified aligned_alloc()
+ * in a way that's incompatible with the Microsoft
+ * implementation of free():
+ * namely, that free() must be able to handle highly aligned allocations.
+ *
+ * We must work around this problem because MSVC is non-compliant!
  */
 
-// Otherwise, test if we are a POSIX or X/Open system
-// This only has a restriction that alignment be a power of 2and a
-// multiple of sizeof(void *).
-#if _POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600 || HAVE_POSIX_MEMALIGN
-
 void *volk_gnsssdr_malloc(size_t size, size_t alignment)
 {
-    void *ptr;
+#if HAVE_POSIX_MEMALIGN
-
     // quoting posix_memalign() man page:
     // "alignment must be a power of two and a multiple of sizeof(void *)"
-    // volk_get_alignment() could return 1 for some machines (e.g. generic_orc)
+    // volk_gnsssdr_get_alignment() could return 1 for some machines (e.g. generic_orc)
     if (alignment == 1)
-        return malloc(size);
-
-    int err = posix_memalign(&ptr, alignment, size);
-    if (err == 0)
         {
-            return ptr;
+            return malloc(size);
         }
-    else
+    void *ptr;
+    int err = posix_memalign(&ptr, alignment, size);
+    if (err != 0)
         {
+            ptr = NULL;
             fprintf(stderr,
                 "VOLK_GNSSSDR: Error allocating memory "
                 "(posix_memalign: error %d: %s)\n",
                 err, strerror(err));
-            return NULL;
         }
-}
+#elif defined(_MSC_VER)
-
-void volk_gnsssdr_free(void *ptr)
-{
-    free(ptr);
-}
-
-// _aligned_malloc has no restriction on size,
-// available on Windows since Visual C++ 2005
-#elif _MSC_VER >= 1400
-
-void *volk_gnsssdr_malloc(size_t size, size_t alignment)
-{
     void *ptr = _aligned_malloc(size, alignment);
+#else
+    void *ptr = aligned_alloc(alignment, size);
+#endif
     if (ptr == NULL)
         {
-            fprintf(stderr, "VOLK_GNSSSDR: Error allocating memory (_aligned_malloc)\n");
+            fprintf(stderr, "VOLK_GNSSSDR: Error allocating memory (aligned_alloc/_aligned_malloc)\n");
         }
     return ptr;
 }
 
 void volk_gnsssdr_free(void *ptr)
 {
+#if defined(_MSC_VER)
     _aligned_free(ptr);
+#else
+    free(ptr);
+#endif
 }
-
-// No standard handlers; we'll do it ourselves.
-#else  // _POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600 || HAVE_POSIX_MEMALIGN
-
-struct block_info
-{
-    void *real;
-};
-
-void *
-volk_gnsssdr_malloc(size_t size, size_t alignment)
-{
-    void *real, *user;
-    struct block_info *info;
-
-    /* At least align to sizeof our struct */
-    if (alignment < sizeof(struct block_info))
-        alignment = sizeof(struct block_info);
-
-    /* Alloc */
-    real = malloc(size + (2 * alignment - 1));
-
-    /* Get pointer to the various zones */
-    user = (void *)((((uintptr_t)real) + sizeof(struct block_info) + alignment - 1) & ~(alignment - 1));
-    info = (struct block_info *)(((uintptr_t)user) - sizeof(struct block_info));
-
-    /* Store the info for the free */
-    info->real = real;
-
-    /* Return pointer to user */
-    return user;
-}
-
-void volk_gnsssdr_free(void *ptr)
-{
-    struct block_info *info;
-
-    /* Get the real pointer */
-    info = (struct block_info *)(((uintptr_t)ptr) - sizeof(struct block_info));
-
-    /* Release real pointer */
-    free(info->real);
-}
-
-#endif  // _POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600 || HAVE_POSIX_MEMALIGN
-
-//#endif  //_ISOC11_SOURCE