diff options
Diffstat (limited to 'm4/gnulib-common.m4')
| -rw-r--r-- | m4/gnulib-common.m4 | 269 |
1 files changed, 246 insertions, 23 deletions
diff --git a/m4/gnulib-common.m4 b/m4/gnulib-common.m4 index f2eff10de6d..12b19dbcb44 100644 --- a/m4/gnulib-common.m4 +++ b/m4/gnulib-common.m4 @@ -1,4 +1,4 @@ -# gnulib-common.m4 serial 63 +# gnulib-common.m4 serial 67 dnl Copyright (C) 2007-2021 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, @@ -85,12 +85,12 @@ AC_DEFUN([gl_COMMON_BODY], [ # define _GL_ATTR_fallthrough _GL_GNUC_PREREQ (7, 0) # define _GL_ATTR_format _GL_GNUC_PREREQ (2, 7) # define _GL_ATTR_leaf _GL_GNUC_PREREQ (4, 6) +# define _GL_ATTR_malloc _GL_GNUC_PREREQ (3, 0) # ifdef _ICC # define _GL_ATTR_may_alias 0 # else # define _GL_ATTR_may_alias _GL_GNUC_PREREQ (3, 3) # endif -# define _GL_ATTR_malloc _GL_GNUC_PREREQ (3, 0) # define _GL_ATTR_noinline _GL_GNUC_PREREQ (3, 1) # define _GL_ATTR_nonnull _GL_GNUC_PREREQ (3, 3) # define _GL_ATTR_nonstring _GL_GNUC_PREREQ (8, 0) @@ -103,26 +103,47 @@ AC_DEFUN([gl_COMMON_BODY], [ # define _GL_ATTR_warn_unused_result _GL_GNUC_PREREQ (3, 4) #endif +#ifdef __has_c_attribute +# define _GL_HAS_C_ATTRIBUTE(attr) __has_c_attribute (__##attr##__) +#else +# define _GL_HAS_C_ATTRIBUTE(attr) 0 +#endif + ]dnl There is no _GL_ATTRIBUTE_ALIGNED; use stdalign's _Alignas instead. [ +/* _GL_ATTRIBUTE_ALLOC_SIZE ((N)) declares that the Nth argument of the function + is the size of the returned memory block. + _GL_ATTRIBUTE_ALLOC_SIZE ((M, N)) declares that the Mth argument multiplied + by the Nth argument of the function is the size of the returned memory block. + */ +/* Applies to: function, pointer to function, function types. */ #if _GL_HAS_ATTRIBUTE (alloc_size) # define _GL_ATTRIBUTE_ALLOC_SIZE(args) __attribute__ ((__alloc_size__ args)) #else # define _GL_ATTRIBUTE_ALLOC_SIZE(args) #endif +/* _GL_ATTRIBUTE_ALWAYS_INLINE tells that the compiler should always inline the + function and report an error if it cannot do so. */ +/* Applies to: function. */ #if _GL_HAS_ATTRIBUTE (always_inline) # define _GL_ATTRIBUTE_ALWAYS_INLINE __attribute__ ((__always_inline__)) #else # define _GL_ATTRIBUTE_ALWAYS_INLINE #endif +/* _GL_ATTRIBUTE_ARTIFICIAL declares that the function is not important to show + in stack traces when debugging. The compiler should omit the function from + stack traces. */ +/* Applies to: function. */ #if _GL_HAS_ATTRIBUTE (artificial) # define _GL_ATTRIBUTE_ARTIFICIAL __attribute__ ((__artificial__)) #else # define _GL_ATTRIBUTE_ARTIFICIAL #endif +/* _GL_ATTRIBUTE_COLD declares that the function is rarely executed. */ +/* Applies to: functions. */ /* Avoid __attribute__ ((cold)) on MinGW; see thread starting at <https://lists.gnu.org/r/emacs-devel/2019-04/msg01152.html>. Also, Oracle Studio 12.6 requires 'cold' not '__cold__'. */ @@ -136,13 +157,41 @@ AC_DEFUN([gl_COMMON_BODY], [ # define _GL_ATTRIBUTE_COLD #endif +/* _GL_ATTRIBUTE_CONST declares that it is OK for a compiler to omit duplicate + calls to the function with the same arguments. + This attribute is safe for a function that neither depends on nor affects + observable state, and always returns exactly once - e.g., does not loop + forever, and does not call longjmp. + (This attribute is stricter than _GL_ATTRIBUTE_PURE.) */ +/* Applies to: functions. */ #if _GL_HAS_ATTRIBUTE (const) # define _GL_ATTRIBUTE_CONST __attribute__ ((__const__)) #else # define _GL_ATTRIBUTE_CONST #endif -#if 201710L < __STDC_VERSION__ +/* _GL_ATTRIBUTE_DEALLOC (F, I) declares that the function returns pointers + that can be freed by passing them as the Ith argument to the + function F. + _GL_ATTRIBUTE_DEALLOC_FREE declares that the function returns pointers that + can be freed via 'free'; it can be used only after declaring 'free'. */ +/* Applies to: functions. Cannot be used on inline functions. */ +#if _GL_GNUC_PREREQ (11, 0) +# define _GL_ATTRIBUTE_DEALLOC(f, i) __attribute__ ((__malloc__ (f, i))) +#else +# define _GL_ATTRIBUTE_DEALLOC(f, i) +#endif +#define _GL_ATTRIBUTE_DEALLOC_FREE _GL_ATTRIBUTE_DEALLOC (free, 1) + +/* _GL_ATTRIBUTE_DEPRECATED: Declares that an entity is deprecated. + The compiler may warn if the entity is used. */ +/* Applies to: + - function, variable, + - struct, union, struct/union member, + - enumeration, enumeration item, + - typedef, + in C++ also: namespace, class, template specialization. */ +#if _GL_HAS_C_ATTRIBUTE (deprecated) # define _GL_ATTRIBUTE_DEPRECATED [[__deprecated__]] #elif _GL_HAS_ATTRIBUTE (deprecated) # define _GL_ATTRIBUTE_DEPRECATED __attribute__ ((__deprecated__)) @@ -150,6 +199,11 @@ AC_DEFUN([gl_COMMON_BODY], [ # define _GL_ATTRIBUTE_DEPRECATED #endif +/* _GL_ATTRIBUTE_ERROR(msg) requests an error if a function is called and + the function call is not optimized away. + _GL_ATTRIBUTE_WARNING(msg) requests a warning if a function is called and + the function call is not optimized away. */ +/* Applies to: functions. */ #if _GL_HAS_ATTRIBUTE (error) # define _GL_ATTRIBUTE_ERROR(msg) __attribute__ ((__error__ (msg))) # define _GL_ATTRIBUTE_WARNING(msg) __attribute__ ((__warning__ (msg))) @@ -161,14 +215,21 @@ AC_DEFUN([gl_COMMON_BODY], [ # define _GL_ATTRIBUTE_WARNING(msg) #endif +/* _GL_ATTRIBUTE_EXTERNALLY_VISIBLE declares that the entity should remain + visible to debuggers etc., even with '-fwhole-program'. */ +/* Applies to: functions, variables. */ #if _GL_HAS_ATTRIBUTE (externally_visible) # define _GL_ATTRIBUTE_EXTERNALLY_VISIBLE __attribute__ ((externally_visible)) #else # define _GL_ATTRIBUTE_EXTERNALLY_VISIBLE #endif -/* FALLTHROUGH is special, because it always expands to something. */ -#if 201710L < __STDC_VERSION__ +/* _GL_ATTRIBUTE_FALLTHROUGH declares that it is not a programming mistake if + the control flow falls through to the immediately following 'case' or + 'default' label. The compiler should not warn in this case. */ +/* Applies to: Empty statement (;), inside a 'switch' statement. */ +/* Always expands to something. */ +#if _GL_HAS_C_ATTRIBUTE (fallthrough) # define _GL_ATTRIBUTE_FALLTHROUGH [[__fallthrough__]] #elif _GL_HAS_ATTRIBUTE (fallthrough) # define _GL_ATTRIBUTE_FALLTHROUGH __attribute__ ((__fallthrough__)) @@ -176,18 +237,47 @@ AC_DEFUN([gl_COMMON_BODY], [ # define _GL_ATTRIBUTE_FALLTHROUGH ((void) 0) #endif +/* _GL_ATTRIBUTE_FORMAT ((ARCHETYPE, STRING-INDEX, FIRST-TO-CHECK)) + declares that the STRING-INDEXth function argument is a format string of + style ARCHETYPE, which is one of: + printf, gnu_printf + scanf, gnu_scanf, + strftime, gnu_strftime, + strfmon, + or the same thing prefixed and suffixed with '__'. + If FIRST-TO-CHECK is not 0, arguments starting at FIRST-TO_CHECK + are suitable for the format string. */ +/* Applies to: functions. */ #if _GL_HAS_ATTRIBUTE (format) # define _GL_ATTRIBUTE_FORMAT(spec) __attribute__ ((__format__ spec)) #else # define _GL_ATTRIBUTE_FORMAT(spec) #endif +/* _GL_ATTRIBUTE_LEAF declares that if the function is called from some other + compilation unit, it executes code from that unit only by return or by + exception handling. This declaration lets the compiler optimize that unit + more aggressively. */ +/* Applies to: functions. */ #if _GL_HAS_ATTRIBUTE (leaf) # define _GL_ATTRIBUTE_LEAF __attribute__ ((__leaf__)) #else # define _GL_ATTRIBUTE_LEAF #endif +/* _GL_ATTRIBUTE_MALLOC declares that the function returns a pointer to freshly + allocated memory. */ +/* Applies to: functions. */ +#if _GL_HAS_ATTRIBUTE (malloc) +# define _GL_ATTRIBUTE_MALLOC __attribute__ ((__malloc__)) +#else +# define _GL_ATTRIBUTE_MALLOC +#endif + +/* _GL_ATTRIBUTE_MAY_ALIAS declares that pointers to the type may point to the + same storage as pointers to other types. Thus this declaration disables + strict aliasing optimization. */ +/* Applies to: types. */ /* Oracle Studio 12.6 mishandles may_alias despite __has_attribute OK. */ #if _GL_HAS_ATTRIBUTE (may_alias) && !defined __SUNPRO_C # define _GL_ATTRIBUTE_MAY_ALIAS __attribute__ ((__may_alias__)) @@ -195,24 +285,33 @@ AC_DEFUN([gl_COMMON_BODY], [ # define _GL_ATTRIBUTE_MAY_ALIAS #endif -#if 201710L < __STDC_VERSION__ +/* _GL_ATTRIBUTE_MAYBE_UNUSED declares that it is not a programming mistake if + the entity is not used. The compiler should not warn if the entity is not + used. */ +/* Applies to: + - function, variable, + - struct, union, struct/union member, + - enumeration, enumeration item, + - typedef, + in C++ also: class. */ +/* In C++ and C2x, this is spelled [[__maybe_unused__]]. + GCC's syntax is __attribute__ ((__unused__)). + clang supports both syntaxes. */ +#if _GL_HAS_C_ATTRIBUTE (maybe_unused) # define _GL_ATTRIBUTE_MAYBE_UNUSED [[__maybe_unused__]] -#elif _GL_HAS_ATTRIBUTE (unused) -# define _GL_ATTRIBUTE_MAYBE_UNUSED __attribute__ ((__unused__)) #else -# define _GL_ATTRIBUTE_MAYBE_UNUSED +# define _GL_ATTRIBUTE_MAYBE_UNUSED _GL_ATTRIBUTE_UNUSED #endif -/* Earlier spellings of this macro. */ +/* Alternative spelling of this macro, for convenience. */ #define _GL_UNUSED _GL_ATTRIBUTE_MAYBE_UNUSED +/* Earlier spellings of this macro. */ #define _UNUSED_PARAMETER_ _GL_ATTRIBUTE_MAYBE_UNUSED -#if _GL_HAS_ATTRIBUTE (malloc) -# define _GL_ATTRIBUTE_MALLOC __attribute__ ((__malloc__)) -#else -# define _GL_ATTRIBUTE_MALLOC -#endif - -#if 201710L < __STDC_VERSION__ +/* _GL_ATTRIBUTE_NODISCARD declares that the caller of the function should not + discard the return value. The compiler may warn if the caller does not use + the return value, unless the caller uses something like ignore_value. */ +/* Applies to: function, enumeration, class. */ +#if _GL_HAS_C_ATTRIBUTE (nodiscard) # define _GL_ATTRIBUTE_NODISCARD [[__nodiscard__]] #elif _GL_HAS_ATTRIBUTE (warn_unused_result) # define _GL_ATTRIBUTE_NODISCARD __attribute__ ((__warn_unused_result__)) @@ -220,18 +319,30 @@ AC_DEFUN([gl_COMMON_BODY], [ # define _GL_ATTRIBUTE_NODISCARD #endif +/* _GL_ATTRIBUTE_NOINLINE tells that the compiler should not inline the + function. */ +/* Applies to: functions. */ #if _GL_HAS_ATTRIBUTE (noinline) # define _GL_ATTRIBUTE_NOINLINE __attribute__ ((__noinline__)) #else # define _GL_ATTRIBUTE_NOINLINE #endif +/* _GL_ATTRIBUTE_NONNULL ((N1, N2,...)) declares that the arguments N1, N2,... + must not be NULL. + _GL_ATTRIBUTE_NONNULL () declares that all pointer arguments must not be + null. */ +/* Applies to: functions. */ #if _GL_HAS_ATTRIBUTE (nonnull) # define _GL_ATTRIBUTE_NONNULL(args) __attribute__ ((__nonnull__ args)) #else # define _GL_ATTRIBUTE_NONNULL(args) #endif +/* _GL_ATTRIBUTE_NONSTRING declares that the contents of a character array is + not meant to be NUL-terminated. */ +/* Applies to: struct/union members and variables that are arrays of element + type '[[un]signed] char'. */ #if _GL_HAS_ATTRIBUTE (nonstring) # define _GL_ATTRIBUTE_NONSTRING __attribute__ ((__nonstring__)) #else @@ -240,41 +351,77 @@ AC_DEFUN([gl_COMMON_BODY], [ /* There is no _GL_ATTRIBUTE_NORETURN; use _Noreturn instead. */ +/* _GL_ATTRIBUTE_NOTHROW declares that the function does not throw exceptions. + */ +/* Applies to: functions. */ #if _GL_HAS_ATTRIBUTE (nothrow) && !defined __cplusplus # define _GL_ATTRIBUTE_NOTHROW __attribute__ ((__nothrow__)) #else # define _GL_ATTRIBUTE_NOTHROW #endif +/* _GL_ATTRIBUTE_PACKED declares: + For struct members: The member has the smallest possible alignment. + For struct, union, class: All members have the smallest possible alignment, + minimizing the memory required. */ +/* Applies to: struct members, struct, union, + in C++ also: class. */ #if _GL_HAS_ATTRIBUTE (packed) # define _GL_ATTRIBUTE_PACKED __attribute__ ((__packed__)) #else # define _GL_ATTRIBUTE_PACKED #endif +/* _GL_ATTRIBUTE_PURE declares that It is OK for a compiler to omit duplicate + calls to the function with the same arguments if observable state is not + changed between calls. + This attribute is safe for a function that does not affect + observable state, and always returns exactly once. + (This attribute is looser than _GL_ATTRIBUTE_CONST.) */ +/* Applies to: functions. */ #if _GL_HAS_ATTRIBUTE (pure) # define _GL_ATTRIBUTE_PURE __attribute__ ((__pure__)) #else # define _GL_ATTRIBUTE_PURE #endif +/* _GL_ATTRIBUTE_RETURNS_NONNULL declares that the function's return value is + a non-NULL pointer. */ +/* Applies to: functions. */ #if _GL_HAS_ATTRIBUTE (returns_nonnull) # define _GL_ATTRIBUTE_RETURNS_NONNULL __attribute__ ((__returns_nonnull__)) #else # define _GL_ATTRIBUTE_RETURNS_NONNULL #endif +/* _GL_ATTRIBUTE_SENTINEL(pos) declares that the variadic function expects a + trailing NULL argument. + _GL_ATTRIBUTE_SENTINEL () - The last argument is NULL (requires C99). + _GL_ATTRIBUTE_SENTINEL ((N)) - The (N+1)st argument from the end is NULL. */ +/* Applies to: functions. */ #if _GL_HAS_ATTRIBUTE (sentinel) # define _GL_ATTRIBUTE_SENTINEL(pos) __attribute__ ((__sentinel__ pos)) #else # define _GL_ATTRIBUTE_SENTINEL(pos) #endif +/* A helper macro. Don't use it directly. */ +#if _GL_HAS_ATTRIBUTE (unused) +# define _GL_ATTRIBUTE_UNUSED __attribute__ ((__unused__)) +#else +# define _GL_ATTRIBUTE_UNUSED +#endif + ]dnl There is no _GL_ATTRIBUTE_VISIBILITY; see m4/visibility.m4 instead. [ -/* To support C++ as well as C, use _GL_UNUSED_LABEL with trailing ';'. */ -#if !defined __cplusplus || _GL_GNUC_PREREQ (4, 5) -# define _GL_UNUSED_LABEL _GL_ATTRIBUTE_MAYBE_UNUSED +/* _GL_UNUSED_LABEL; declares that it is not a programming mistake if the + immediately preceding label is not used. The compiler should not warn + if the label is not used. */ +/* Applies to: label (both in C and C++). */ +/* Note that g++ < 4.5 does not support the '__attribute__ ((__unused__)) ;' + syntax. But clang does. */ +#if !(defined __cplusplus && !_GL_GNUC_PREREQ (4, 5)) || defined __clang__ +# define _GL_UNUSED_LABEL _GL_ATTRIBUTE_UNUSED #else # define _GL_UNUSED_LABEL #endif @@ -357,6 +504,16 @@ AC_DEFUN([gl_COMMON_BODY], [ export LIBC_FATAL_STDERR_ ]) +# gl_MODULE_INDICATOR_INIT_VARIABLE([variablename]) +# gl_MODULE_INDICATOR_INIT_VARIABLE([variablename], [initialvalue]) +# initializes the shell variable that indicates the presence of the given module +# as a C preprocessor expression. +AC_DEFUN([gl_MODULE_INDICATOR_INIT_VARIABLE], +[ + GL_MODULE_INDICATOR_PREFIX[]_[$1]=m4_if([$2], , [0], [$2]) + AC_SUBST(GL_MODULE_INDICATOR_PREFIX[]_[$1]) +]) + # gl_MODULE_INDICATOR_CONDITION # expands to a C preprocessor expression that evaluates to 1 or 0, depending # whether a gnulib module that has been requested shall be considered present @@ -369,9 +526,9 @@ m4_define([gl_MODULE_INDICATOR_CONDITION], [1]) AC_DEFUN([gl_MODULE_INDICATOR_SET_VARIABLE], [ gl_MODULE_INDICATOR_SET_VARIABLE_AUX( - [GNULIB_[]m4_translit([[$1]], - [abcdefghijklmnopqrstuvwxyz./-], - [ABCDEFGHIJKLMNOPQRSTUVWXYZ___])], + [GL_MODULE_INDICATOR_PREFIX[]_GNULIB_[]m4_translit([[$1]], + [abcdefghijklmnopqrstuvwxyz./-], + [ABCDEFGHIJKLMNOPQRSTUVWXYZ___])], [gl_MODULE_INDICATOR_CONDITION]) ]) @@ -656,6 +813,72 @@ AC_DEFUN([gl_CACHE_VAL_SILENT], ]) ]) +# gl_CC_ALLOW_WARNINGS +# sets and substitutes a variable GL_CFLAG_ALLOW_WARNINGS, to a $(CC) option +# that reverts a preceding '-Werror' option, if available. +# This is expected to be '-Wno-error' on gcc, clang (except clang/MSVC), xlclang +# and empty otherwise. +AC_DEFUN([gl_CC_ALLOW_WARNINGS], +[ + AC_REQUIRE([AC_PROG_CC]) + AC_CACHE_CHECK([for C compiler option to allow warnings], + [gl_cv_cc_wallow], + [rm -f conftest* + echo 'int dummy;' > conftest.c + AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS -c conftest.c 2>conftest1.err]) >/dev/null + AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS -Wno-error -c conftest.c 2>conftest2.err]) >/dev/null + dnl Test the number of error output lines, because AIX xlc accepts the + dnl option '-Wno-error', just to produce a warning + dnl "Option -Wno-error was incorrectly specified. The option will be ignored." + dnl afterwards. + if test $? = 0 && test `wc -l < conftest1.err` = `wc -l < conftest2.err`; then + gl_cv_cc_wallow='-Wno-error' + else + gl_cv_cc_wallow=none + fi + rm -f conftest* + ]) + case "$gl_cv_cc_wallow" in + none) GL_CFLAG_ALLOW_WARNINGS='' ;; + *) GL_CFLAG_ALLOW_WARNINGS="$gl_cv_cc_wallow" ;; + esac + AC_SUBST([GL_CFLAG_ALLOW_WARNINGS]) +]) + +# gl_CXX_ALLOW_WARNINGS +# sets and substitutes a variable GL_CXXFLAG_ALLOW_WARNINGS, to a $(CC) option +# that reverts a preceding '-Werror' option, if available. +AC_DEFUN([gl_CXX_ALLOW_WARNINGS], +[ + dnl Requires AC_PROG_CXX or gl_PROG_ANSI_CXX. + if test -n "$CXX" && test "$CXX" != no; then + AC_CACHE_CHECK([for C++ compiler option to allow warnings], + [gl_cv_cxx_wallow], + [rm -f conftest* + echo 'int dummy;' > conftest.cc + AC_TRY_COMMAND([${CXX-c++} $CXXFLAGS $CPPFLAGS -c conftest.cc 2>conftest1.err]) >/dev/null + AC_TRY_COMMAND([${CXX-c++} $CXXFLAGS $CPPFLAGS -Wno-error -c conftest.cc 2>conftest2.err]) >/dev/null + dnl Test the number of error output lines, because AIX xlC accepts the + dnl option '-Wno-error', just to produce a warning + dnl "Option -Wno-error was incorrectly specified. The option will be ignored." + dnl afterwards. + if test $? = 0 && test `wc -l < conftest1.err` = `wc -l < conftest2.err`; then + gl_cv_cxx_wallow='-Wno-error' + else + gl_cv_cxx_wallow=none + fi + rm -f conftest* + ]) + case "$gl_cv_cxx_wallow" in + none) GL_CXXFLAG_ALLOW_WARNINGS='' ;; + *) GL_CXXFLAG_ALLOW_WARNINGS="$gl_cv_cxx_wallow" ;; + esac + else + GL_CXXFLAG_ALLOW_WARNINGS='' + fi + AC_SUBST([GL_CXXFLAG_ALLOW_WARNINGS]) +]) + dnl Expands to some code for use in .c programs that, on native Windows, defines dnl the Microsoft deprecated alias function names to the underscore-prefixed dnl actual function names. With this macro, these function names are available |