1# manywarnings.m4 serial 21
2dnl Copyright (C) 2008-2021 Free Software Foundation, Inc.
3dnl This file is free software; the Free Software Foundation
4dnl gives unlimited permission to copy and/or distribute it,
5dnl with or without modifications, as long as this notice is preserved.
6
7dnl From Simon Josefsson
8
9# gl_MANYWARN_COMPLEMENT(OUTVAR, LISTVAR, REMOVEVAR)
10# --------------------------------------------------
11# Copy LISTVAR to OUTVAR except for the entries in REMOVEVAR.
12# Elements separated by whitespace.  In set logic terms, the function
13# does OUTVAR = LISTVAR \ REMOVEVAR.
14AC_DEFUN([gl_MANYWARN_COMPLEMENT],
15[
16  gl_warn_set=
17  set x $2; shift
18  for gl_warn_item
19  do
20    case " $3 " in
21      *" $gl_warn_item "*)
22        ;;
23      *)
24        gl_AS_VAR_APPEND([gl_warn_set], [" $gl_warn_item"])
25        ;;
26    esac
27  done
28  $1=$gl_warn_set
29])
30
31# gl_MANYWARN_ALL_GCC(VARIABLE)
32# -----------------------------
33# Add all documented GCC warning parameters to variable VARIABLE.
34# Note that you need to test them using gl_WARN_ADD if you want to
35# make sure your gcc understands it.
36#
37# The effects of this macro depend on the current language (_AC_LANG).
38AC_DEFUN([gl_MANYWARN_ALL_GCC],
39[_AC_LANG_DISPATCH([$0], _AC_LANG, $@)])
40
41# Specialization for _AC_LANG = C.
42AC_DEFUN([gl_MANYWARN_ALL_GCC(C)],
43[
44  AC_LANG_PUSH([C])
45
46  dnl First, check for some issues that only occur when combining multiple
47  dnl gcc warning categories.
48  AC_REQUIRE([AC_PROG_CC])
49  if test -n "$GCC"; then
50
51    dnl Check if -Wextra -Werror -Wno-missing-field-initializers is supported
52    dnl with the current $CC $CFLAGS $CPPFLAGS.
53    AC_CACHE_CHECK([whether -Wno-missing-field-initializers is supported],
54      [gl_cv_cc_nomfi_supported],
55      [gl_save_CFLAGS="$CFLAGS"
56       CFLAGS="$CFLAGS -Wextra -Werror -Wno-missing-field-initializers"
57       AC_COMPILE_IFELSE(
58         [AC_LANG_PROGRAM([[]], [[]])],
59         [gl_cv_cc_nomfi_supported=yes],
60         [gl_cv_cc_nomfi_supported=no])
61       CFLAGS="$gl_save_CFLAGS"
62      ])
63
64    if test "$gl_cv_cc_nomfi_supported" = yes; then
65      dnl Now check whether -Wno-missing-field-initializers is needed
66      dnl for the { 0, } construct.
67      AC_CACHE_CHECK([whether -Wno-missing-field-initializers is needed],
68        [gl_cv_cc_nomfi_needed],
69        [gl_save_CFLAGS="$CFLAGS"
70         CFLAGS="$CFLAGS -Wextra -Werror"
71         AC_COMPILE_IFELSE(
72           [AC_LANG_PROGRAM(
73              [[int f (void)
74                {
75                  typedef struct { int a; int b; } s_t;
76                  s_t s1 = { 0, };
77                  return s1.b;
78                }
79              ]],
80              [[]])],
81           [gl_cv_cc_nomfi_needed=no],
82           [gl_cv_cc_nomfi_needed=yes])
83         CFLAGS="$gl_save_CFLAGS"
84        ])
85    fi
86
87    dnl Next, check if -Werror -Wuninitialized is useful with the
88    dnl user's choice of $CFLAGS; some versions of gcc warn that it
89    dnl has no effect if -O is not also used
90    AC_CACHE_CHECK([whether -Wuninitialized is supported],
91      [gl_cv_cc_uninitialized_supported],
92      [gl_save_CFLAGS="$CFLAGS"
93       CFLAGS="$CFLAGS -Werror -Wuninitialized"
94       AC_COMPILE_IFELSE(
95         [AC_LANG_PROGRAM([[]], [[]])],
96         [gl_cv_cc_uninitialized_supported=yes],
97         [gl_cv_cc_uninitialized_supported=no])
98       CFLAGS="$gl_save_CFLAGS"
99      ])
100
101  fi
102
103  # List all gcc warning categories.
104  # To compare this list to your installed GCC's, run this Bash command:
105  #
106  # comm -3 \
107  #  <((sed -n 's/^  *\(-[^ 0-9][^ ]*\).*/\1/p' manywarnings.m4; \
108  #     awk '/^[^#]/ {print $1}' ../build-aux/gcc-warning.spec) | sort) \
109  #  <(LC_ALL=C gcc --help=warnings | sed -n 's/^  \(-[^ ]*\) .*/\1/p' | sort)
110
111  $1=
112  for gl_manywarn_item in -fanalyzer -fno-common \
113    -Wall \
114    -Warith-conversion \
115    -Wbad-function-cast \
116    -Wcast-align=strict \
117    -Wdate-time \
118    -Wdisabled-optimization \
119    -Wdouble-promotion \
120    -Wduplicated-branches \
121    -Wduplicated-cond \
122    -Wextra \
123    -Wformat-signedness \
124    -Winit-self \
125    -Winline \
126    -Winvalid-pch \
127    -Wlogical-op \
128    -Wmissing-declarations \
129    -Wmissing-include-dirs \
130    -Wmissing-prototypes \
131    -Wnested-externs \
132    -Wnull-dereference \
133    -Wold-style-definition \
134    -Wopenmp-simd \
135    -Woverlength-strings \
136    -Wpacked \
137    -Wpointer-arith \
138    -Wshadow \
139    -Wstack-protector \
140    -Wstrict-overflow \
141    -Wstrict-prototypes \
142    -Wsuggest-attribute=cold \
143    -Wsuggest-attribute=const \
144    -Wsuggest-attribute=format \
145    -Wsuggest-attribute=malloc \
146    -Wsuggest-attribute=noreturn \
147    -Wsuggest-attribute=pure \
148    -Wsuggest-final-methods \
149    -Wsuggest-final-types \
150    -Wsync-nand \
151    -Wsystem-headers \
152    -Wtrampolines \
153    -Wuninitialized \
154    -Wunknown-pragmas \
155    -Wunsafe-loop-optimizations \
156    -Wunused-macros \
157    -Wvariadic-macros \
158    -Wvector-operation-performance \
159    -Wvla \
160    -Wwrite-strings \
161    \
162    ; do
163    gl_AS_VAR_APPEND([$1], [" $gl_manywarn_item"])
164  done
165
166  # gcc --help=warnings outputs an unusual form for these options; list
167  # them here so that the above 'comm' command doesn't report a false match.
168  gl_AS_VAR_APPEND([$1], [' -Warray-bounds=2'])
169  gl_AS_VAR_APPEND([$1], [' -Wattribute-alias=2'])
170  gl_AS_VAR_APPEND([$1], [' -Wformat-overflow=2'])
171  gl_AS_VAR_APPEND([$1], [' -Wformat=2'])
172  gl_AS_VAR_APPEND([$1], [' -Wformat-truncation=2'])
173  gl_AS_VAR_APPEND([$1], [' -Wimplicit-fallthrough=5'])
174  gl_AS_VAR_APPEND([$1], [' -Wshift-overflow=2'])
175  gl_AS_VAR_APPEND([$1], [' -Wunused-const-variable=2'])
176  gl_AS_VAR_APPEND([$1], [' -Wvla-larger-than=4031'])
177
178  # These are needed for older GCC versions.
179  if test -n "$GCC"; then
180    case `($CC --version) 2>/dev/null` in
181      'gcc (GCC) '[[0-3]].* | \
182      'gcc (GCC) '4.[[0-7]].*)
183        gl_AS_VAR_APPEND([$1], [' -fdiagnostics-show-option'])
184        gl_AS_VAR_APPEND([$1], [' -funit-at-a-time'])
185          ;;
186    esac
187  fi
188
189  # Disable specific options as needed.
190  if test "$gl_cv_cc_nomfi_needed" = yes; then
191    gl_AS_VAR_APPEND([$1], [' -Wno-missing-field-initializers'])
192  fi
193
194  if test "$gl_cv_cc_uninitialized_supported" = no; then
195    gl_AS_VAR_APPEND([$1], [' -Wno-uninitialized'])
196  fi
197
198  # Some warnings have too many false alarms in GCC 10.1.
199  # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93695
200  gl_AS_VAR_APPEND([$1], [' -Wno-analyzer-double-free'])
201  # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94458
202  gl_AS_VAR_APPEND([$1], [' -Wno-analyzer-malloc-leak'])
203  # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94851
204  gl_AS_VAR_APPEND([$1], [' -Wno-analyzer-null-dereference'])
205  # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95758
206  gl_AS_VAR_APPEND([$1], [' -Wno-analyzer-use-after-free'])
207
208  AC_LANG_POP([C])
209])
210
211# Specialization for _AC_LANG = C++.
212AC_DEFUN([gl_MANYWARN_ALL_GCC(C++)],
213[
214  gl_MANYWARN_ALL_GCC_CXX_IMPL([$1])
215])
216