Add configure options for disabling extension features (#4277)

Add configure option to enable or disable extension features in general

Add configure option to enable or disable _Float16 support

Add new config options to various settings files

config/cmake/ConfigureChecks.cmake

@@ -871,13 +871,28 @@ H5ConversionTests (${HDF_PREFIX}_LLONG_TO_LDOUBLE_CORRECT TRUE "Checking IF corr
 #-----------------------------------------------------------------------------
 H5ConversionTests (${HDF_PREFIX}_DISABLE_SOME_LDOUBLE_CONV FALSE "Checking IF the cpu is power9 and cannot correctly converting long double values")
 
+#-----------------------------------------------------------------------------
+# Options for enabling/disabling support for non-standard features, datatypes,
+# etc. These features should still be checked for at configure time, but these
+# options allow disabling of support for these features when compiler support
+# is incomplete or broken. In this case, configure time checks may not be
+# enough to properly enable/disable a feature and can cause library build
+# problems.
+#-----------------------------------------------------------------------------
+# Option to enable or disable all non-standard features. Specific features can
+# be enabled or disabled with their respective options below
+option (HDF5_ENABLE_NONSTANDARD_FEATURES "Enable support for non-standard programming language features" ON)
+# Options for enabling or disabling individual features
+option (HDF5_ENABLE_NONSTANDARD_FEATURE_FLOAT16 "Enable support for _Float16 C datatype" ${HDF5_ENABLE_NONSTANDARD_FEATURES})
+
 #-----------------------------------------------------------------------------
 # Check if _Float16 type is available
 #-----------------------------------------------------------------------------
-message (STATUS "Checking if _Float16 support is available")
-set (${HDF_PREFIX}_HAVE__FLOAT16 0)
-HDF_CHECK_TYPE_SIZE (_Float16 ${HDF_PREFIX}_SIZEOF__FLOAT16)
-if (${HDF_PREFIX}_SIZEOF__FLOAT16)
+if (HDF5_ENABLE_NONSTANDARD_FEATURE_FLOAT16)
+  message (STATUS "Checking if _Float16 support is available")
+  HDF_CHECK_TYPE_SIZE (_Float16 ${HDF_PREFIX}_SIZEOF__FLOAT16)
+
+  if (${HDF_PREFIX}_SIZEOF__FLOAT16)
     # Request _Float16 support
     set (CMAKE_REQUIRED_DEFINITIONS ${CMAKE_REQUIRED_DEFINITIONS} "-D__STDC_WANT_IEC_60559_TYPES_EXT__")
 
@@ -959,6 +974,11 @@ if (${HDF_PREFIX}_SIZEOF__FLOAT16)
     else ()
       message (STATUS "_Float16 support has been disabled since the required macros (FLT16_MAX, FLT16_EPSILON, etc. were not found)")
     endif ()
-else ()
+  else ()
     message (STATUS "_Float16 support has been disabled since the _Float16 type was not found")
+  endif ()
+else ()
+  set (${HDF_PREFIX}_SIZEOF__FLOAT16 0 CACHE INTERNAL "SizeOf for ${HDF_PREFIX}_SIZEOF__FLOAT16")
+  unset (${HDF_PREFIX}_HAVE__FLOAT16 CACHE)
+  unset (${HDF_PREFIX}_LDOUBLE_TO_FLOAT16_CORRECT CACHE)
 endif ()

config/cmake/hdf5-config.cmake.in

@@ -54,6 +54,8 @@ set (${HDF5_PACKAGE_NAME}_BUILD_TOOLS           @HDF5_BUILD_TOOLS@)
 set (${HDF5_PACKAGE_NAME}_BUILD_HL_GIF_TOOLS    @HDF5_BUILD_HL_GIF_TOOLS@)
 set (${HDF5_PACKAGE_NAME}_BUILD_STATIC_TOOLS    @HDF5_BUILD_STATIC_TOOLS@)
 #-----------------------------------------------------------------------------
+set (${HDF5_PACKAGE_NAME}_ENABLE_NONSTANDARD_FEATURE_FLOAT16 @HDF5_ENABLE_NONSTANDARD_FEATURE_FLOAT16@)
+#-----------------------------------------------------------------------------
 set (${HDF5_PACKAGE_NAME}_ENABLE_Z_LIB_SUPPORT  @HDF5_ENABLE_Z_LIB_SUPPORT@)
 set (${HDF5_PACKAGE_NAME}_ENABLE_SZIP_SUPPORT   @HDF5_ENABLE_SZIP_SUPPORT@)
 set (${HDF5_PACKAGE_NAME}_ENABLE_SZIP_ENCODING  @HDF5_ENABLE_SZIP_ENCODING@)

config/cmake/libhdf5.settings.cmake.in

@@ -78,6 +78,7 @@ Dimension scales w/ new references: @DIMENSION_SCALES_WITH_NEW_REF@
                Default API mapping: @DEFAULT_API_VERSION@
     With deprecated public symbols: @HDF5_ENABLE_DEPRECATED_SYMBOLS@
             I/O filters (external): @EXTERNAL_FILTERS@
+                  _Float16 support: @HDF5_ENABLE_NONSTANDARD_FEATURE_FLOAT16@
                      Map (H5M) API: @H5_HAVE_MAP_API@
                         Direct VFD: @HDF5_ENABLE_DIRECT_VFD@
                         Mirror VFD: @H5_HAVE_MIRROR_VFD@

configure.ac

@@ -574,13 +574,62 @@ AC_CHECK_SIZEOF([float])
 AC_CHECK_SIZEOF([double])
 AC_CHECK_SIZEOF([long double])
 
+#-----------------------------------------------------------------------------
+# Option for enabling/disabling support for non-standard features, datatypes,
+# etc. These features should still be checked for at configure time, but these
+# options allow disabling of support for these features when compiler support
+# is incomplete or broken. In this case, configure time checks may not be
+# enough to properly enable/disable a feature and can cause library build
+# problems.
+#-----------------------------------------------------------------------------
+AC_MSG_CHECKING([if non-standard feature support is enabled])
+AC_ARG_ENABLE([nonstandard-features],
+              [AS_HELP_STRING([--enable-nonstandard-features],
+                              [Enable support for non-standard programming language features [default=yes]])],
+              [NONSTANDARD_FEATURES=$enableval])
+
+## Set default
+if test "X-$NONSTANDARD_FEATURES" = X- ; then
+  NONSTANDARD_FEATURES=yes
+fi
+
+case "X-$NONSTANDARD_FEATURES" in
+  X-yes|X-no)
+    AC_MSG_RESULT([$NONSTANDARD_FEATURES])
+    ;;
+  *)
+    AC_MSG_ERROR([Unrecognized value: $NONSTANDARD_FEATURES])
+    ;;
+esac
+
 ## ----------------------------------------------------------------------
 ## Check if _Float16 support is available
 ##
-AC_MSG_NOTICE([checking if _Float16 support is available])
+AC_MSG_CHECKING([if _Float16 support is enabled])
+AC_ARG_ENABLE([nonstandard-feature-float16],
+              [AS_HELP_STRING([--enable-nonstandard-feature-float16],
+                              [Enable support for _Float16 C datatype [default=yes]])],
+              [ENABLE_FLOAT16=$enableval])
+
+## Set default
+if test "X-$ENABLE_FLOAT16" = X- ; then
+  ENABLE_FLOAT16=$NONSTANDARD_FEATURES
+fi
+
+case "X-$ENABLE_FLOAT16" in
+  X-yes|X-no)
+    AC_MSG_RESULT([$ENABLE_FLOAT16])
+    ;;
+  *)
+    AC_MSG_ERROR([Unrecognized value: $ENABLE_FLOAT16])
+    ;;
+esac
+
 HAVE__FLOAT16="no"
-AC_CHECK_SIZEOF([_Float16])
-if test "$ac_cv_sizeof__Float16" != 0; then
+if test "X$ENABLE_FLOAT16" = "Xyes"; then
+  AC_MSG_NOTICE([checking if _Float16 support is available])
+  AC_CHECK_SIZEOF([_Float16])
+  if test "$ac_cv_sizeof__Float16" != 0; then
     # Some compilers expose the _Float16 datatype, but not the macros and
     # functions used with the datatype. We need the macros for proper
     # datatype conversion support. Check for these here.
@@ -672,6 +721,9 @@ if test "$ac_cv_sizeof__Float16" != 0; then
 
     AC_MSG_CHECKING([if _Float16 support is enabled])
     AC_MSG_RESULT([$HAVE__FLOAT16])
+  fi
+else
+  AC_DEFINE([SIZEOF__FLOAT16], [0])
 fi
 
 # Define HAVE__FLOAT16 value to substitute into other files for conditional testing

release_docs/RELEASE.txt

@@ -47,6 +47,36 @@ New Features
 
     Configuration:
     -------------
+    - Added configure options for enabling/disabling non-standard programming
+      language features
+
+      * Added a new configuration option that allows enabling or disabling of
+        support for features that are extensions to programming languages, such
+        as support for the _Float16 datatype:
+
+          CMake:      HDF5_ENABLE_NONSTANDARD_FEATURES (ON/OFF) (Default: ON)
+          Autotools:  --enable-nonstandard-features    (yes/no) (Default: yes)
+
+        When this option is enabled, configure time checks are still performed
+        to ensure that a feature can be used properly, but these checks may not
+        be sufficient when compiler support for a feature is incomplete or broken,
+        resulting in library build failures. When set to OFF/no, this option
+        provides a way to disable support for all non-standard features to avoid
+        these issues. Individual features can still be re-enabled with their
+        respective configuration options.
+
+      * Added a new configuration option that allows enabling or disabling of
+        support for the _Float16 C datatype:
+
+          CMake:      HDF5_ENABLE_NONSTANDARD_FEATURE_FLOAT16 (ON/OFF) (Default: ON)
+          Autotools:  --enable-nonstandard-feature-float16    (yes/no) (Default: yes)
+
+        While support for the _Float16 C datatype can generally be detected and
+        used properly, some compilers have incomplete support for the datatype
+        and will pass configure time checks while still failing to build HDF5.
+        This option provides a way to disable support for the _Float16 datatype
+        when the compiler doesn't have the proper support for it.
+
     - Deprecate bin/cmakehdf5 script
 
       With the improvements made in CMake since version 3.23 and the addition

src/H5build_settings.autotools.c.in

@@ -99,6 +99,7 @@ const char H5build_settings[]=
     "               Default API mapping: @DEFAULT_API_VERSION@\n"
     "    With deprecated public symbols: @DEPRECATED_SYMBOLS@\n"
     "            I/O filters (external): @EXTERNAL_FILTERS@\n"
+    "                  _Float16 support: @HAVE__FLOAT16@\n"
     "                     Map (H5M) API: @MAP_API@\n"
     "                        Direct VFD: @DIRECT_VFD@\n"
     "                        Mirror VFD: @MIRROR_VFD@\n"

src/H5build_settings.cmake.c.in

@@ -98,6 +98,7 @@ const char H5build_settings[]=
     "               Default API mapping: @DEFAULT_API_VERSION@\n"
     "    With deprecated public symbols: @HDF5_ENABLE_DEPRECATED_SYMBOLS@\n"
     "            I/O filters (external): @EXTERNAL_FILTERS@\n"
+    "                  _Float16 support: @HDF5_ENABLE_NONSTANDARD_FEATURE_FLOAT16@\n"
     "                     Map (H5M) API: @H5_HAVE_MAP_API@\n"
     "                        Direct VFD: @H5_HAVE_DIRECT@\n"
     "                        Mirror VFD: @H5_HAVE_MIRROR_VFD@\n"

src/libhdf5.settings.in

@@ -80,6 +80,7 @@ Dimension scales w/ new references: @DIMENSION_SCALES_WITH_NEW_REF@
                Default API mapping: @DEFAULT_API_VERSION@
     With deprecated public symbols: @DEPRECATED_SYMBOLS@
             I/O filters (external): @EXTERNAL_FILTERS@
+                  _Float16 support: @HAVE__FLOAT16@
                      Map (H5M) API: @MAP_API@
                         Direct VFD: @DIRECT_VFD@
                         Mirror VFD: @MIRROR_VFD@