[virt-tools-list] [virt-viewer PATCH v2 3/3] Switch to gnulib's compiler warning flags

Daniel P. Berrangé berrange at redhat.com
Tue Feb 19 15:00:11 UTC 2019


This enables many more compiler warnings than the current code. It also
ensures that -Werror is enabled by default when building from GIT so
that maintainers see regressions as hard failures.

Reviewed-by: Marc-André Lureau <marcandre.lureau at redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange at redhat.com>
---
 acinclude.m4               |  98 -----------
 configure.ac               |   2 +-
 m4/manywarnings.m4         | 334 +++++++++++++++++++++++++++++++++++++
 m4/virt-viewer-warnings.m4 | 159 ++++++++++++++++++
 m4/warnings.m4             | 115 +++++++++++++
 prepare-release.sh         |   2 +-
 6 files changed, 610 insertions(+), 100 deletions(-)
 delete mode 100644 acinclude.m4
 create mode 100644 m4/manywarnings.m4
 create mode 100644 m4/virt-viewer-warnings.m4
 create mode 100644 m4/warnings.m4

diff --git a/acinclude.m4 b/acinclude.m4
deleted file mode 100644
index 68398a6..0000000
--- a/acinclude.m4
+++ /dev/null
@@ -1,98 +0,0 @@
-dnl
-dnl Taken from gnome-common/macros2/gnome-compiler-flags.m4
-dnl
-dnl We've added:
-dnl   -Wextra -Wshadow -Wcast-align -Wwrite-strings -Waggregate-return -Wstrict-prototypes -Winline -Wredundant-decls
-dnl We've removed
-dnl   CFLAGS="$realsave_CFLAGS"
-dnl   to avoid clobbering user-specified CFLAGS
-dnl
-AC_DEFUN([VIRT_VIEWER_COMPILE_WARNINGS],[
-    dnl ******************************
-    dnl More compiler warnings
-    dnl ******************************
-
-    AC_ARG_ENABLE(compile-warnings,
-                  AC_HELP_STRING([--enable-compile-warnings=@<:@no/minimum/yes/maximum/error@:>@],
-                                 [Turn on compiler warnings]),,
-                  [enable_compile_warnings="m4_default([$1],[maximum])"])
-
-    warnCFLAGS=
-
-    try_compiler_flags="-fexceptions -fstack-protector --param=ssp-buffer-size=4 -fasynchronous-unwind-tables"
-
-    case "$enable_compile_warnings" in
-    no)
-	;;
-    minimum)
-	try_compiler_flags="$try_compiler_flags -Wall"
-	;;
-    yes)
-	try_compiler_flags="$try_compiler_flags -Wall -Wmissing-prototypes -std=c99"
-	;;
-    maximum|error)
-	try_compiler_flags="$try_compiler_flags -Wall -Wmissing-prototypes -std=c99 -Wnested-externs -Wpointer-arith"
-        try_compiler_flags="$try_compiler_flags -Wextra -Wshadow -Wcast-align -Wwrite-strings -Waggregate-return"
-        # Removed -Wstrict-prototypes to avoid GTK bug
-	try_compiler_flags="$try_compiler_flags -Winline -Wredundant-decls -Wdeprecated-declarations -Wno-sign-compare"
-	# Remove as glib function casts hit
-	try_compiler_flags="$try_compiler_flags -Wno-cast-function-type"
-	if test "$enable_compile_warnings" = "error" ; then
-	    try_compiler_flags="$try_compiler_flags -Werror"
-	fi
-	;;
-    *)
-	AC_MSG_ERROR(Unknown argument '$enable_compile_warnings' to --enable-compile-warnings)
-	;;
-    esac
-
-    AH_VERBATIM([FORTIFY_SOURCE],
-                [/* Enable compile-time and run-time bounds-checking, and some warnings. */
-                 #if !defined _FORTIFY_SOURCE && defined __OPTIMIZE__ && __OPTIMIZE__
-                 # define _FORTIFY_SOURCE 2
-                 #endif
-                ])
-
-    compiler_flags=
-    for option in $try_compiler_flags; do
-	SAVE_CFLAGS="$CFLAGS"
-	CFLAGS="$CFLAGS $option"
-	AC_MSG_CHECKING([whether gcc understands $option])
-	AC_TRY_COMPILE([], [],
-		has_option=yes,
-		has_option=no,)
-	CFLAGS="$SAVE_CFLAGS"
-	AC_MSG_RESULT($has_option)
-	if test $has_option = yes; then
-	  compiler_flags="$compiler_flags $option"
-	fi
-	unset has_option
-	unset SAVE_CFLAGS
-    done
-    unset option
-    unset try_compiler_flags
-
-    AC_ARG_ENABLE(iso-c,
-                  AC_HELP_STRING([--enable-iso-c],
-                                 [Try to warn if code is not ISO C ]),,
-                  [enable_iso_c=no])
-
-    AC_MSG_CHECKING(what language compliance flags to pass to the C compiler)
-    complCFLAGS=
-    if test "x$enable_iso_c" != "xno"; then
-	if test "x$GCC" = "xyes"; then
-	case " $CFLAGS " in
-	    *[\ \	]-ansi[\ \	]*) ;;
-	    *) complCFLAGS="$complCFLAGS -ansi" ;;
-	esac
-	case " $CFLAGS " in
-	    *[\ \	]-pedantic[\ \	]*) ;;
-	    *) complCFLAGS="$complCFLAGS -pedantic" ;;
-	esac
-	fi
-    fi
-    AC_MSG_RESULT($complCFLAGS)
-
-    WARN_CFLAGS="$compiler_flags $complCFLAGS"
-    AC_SUBST(WARN_CFLAGS)
-])
diff --git a/configure.ac b/configure.ac
index 5598c61..8ff69ac 100644
--- a/configure.ac
+++ b/configure.ac
@@ -90,7 +90,7 @@ m4_if(m4_version_compare([2.61a.100],
       [AC_CONFIG_LINKS([$GNUmakefile:$GNUmakefile], [],
         [GNUmakefile=$GNUmakefile])])
 
-VIRT_VIEWER_COMPILE_WARNINGS(maximum)
+VIRT_VIEWER_COMPILE_WARNINGS()
 
 GETTEXT_PACKAGE=virt-viewer
 AC_SUBST(GETTEXT_PACKAGE)
diff --git a/m4/manywarnings.m4 b/m4/manywarnings.m4
new file mode 100644
index 0000000..e0488a5
--- /dev/null
+++ b/m4/manywarnings.m4
@@ -0,0 +1,334 @@
+# manywarnings.m4 serial 17
+dnl Copyright (C) 2008-2019 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Simon Josefsson
+
+# gl_MANYWARN_COMPLEMENT(OUTVAR, LISTVAR, REMOVEVAR)
+# --------------------------------------------------
+# Copy LISTVAR to OUTVAR except for the entries in REMOVEVAR.
+# Elements separated by whitespace.  In set logic terms, the function
+# does OUTVAR = LISTVAR \ REMOVEVAR.
+AC_DEFUN([gl_MANYWARN_COMPLEMENT],
+[
+  gl_warn_set=
+  set x $2; shift
+  for gl_warn_item
+  do
+    case " $3 " in
+      *" $gl_warn_item "*)
+        ;;
+      *)
+        gl_warn_set="$gl_warn_set $gl_warn_item"
+        ;;
+    esac
+  done
+  $1=$gl_warn_set
+])
+
+# gl_MANYWARN_ALL_GCC(VARIABLE)
+# -----------------------------
+# Add all documented GCC warning parameters to variable VARIABLE.
+# Note that you need to test them using gl_WARN_ADD if you want to
+# make sure your gcc understands it.
+#
+# The effects of this macro depend on the current language (_AC_LANG).
+AC_DEFUN([gl_MANYWARN_ALL_GCC],
+[_AC_LANG_DISPATCH([$0], _AC_LANG, $@)])
+
+# Specialization for _AC_LANG = C.
+# Use of m4_defun rather than AC_DEFUN works around a bug in autoconf < 2.63b.
+m4_defun([gl_MANYWARN_ALL_GCC(C)],
+[
+  AC_LANG_PUSH([C])
+
+  dnl First, check for some issues that only occur when combining multiple
+  dnl gcc warning categories.
+  AC_REQUIRE([AC_PROG_CC])
+  if test -n "$GCC"; then
+
+    dnl Check if -W -Werror -Wno-missing-field-initializers is supported
+    dnl with the current $CC $CFLAGS $CPPFLAGS.
+    AC_CACHE_CHECK([whether -Wno-missing-field-initializers is supported],
+      [gl_cv_cc_nomfi_supported],
+      [gl_save_CFLAGS="$CFLAGS"
+       CFLAGS="$CFLAGS -W -Werror -Wno-missing-field-initializers"
+       AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM([[]], [[]])],
+         [gl_cv_cc_nomfi_supported=yes],
+         [gl_cv_cc_nomfi_supported=no])
+       CFLAGS="$gl_save_CFLAGS"
+      ])
+
+    if test "$gl_cv_cc_nomfi_supported" = yes; then
+      dnl Now check whether -Wno-missing-field-initializers is needed
+      dnl for the { 0, } construct.
+      AC_CACHE_CHECK([whether -Wno-missing-field-initializers is needed],
+        [gl_cv_cc_nomfi_needed],
+        [gl_save_CFLAGS="$CFLAGS"
+         CFLAGS="$CFLAGS -W -Werror"
+         AC_COMPILE_IFELSE(
+           [AC_LANG_PROGRAM(
+              [[int f (void)
+                {
+                  typedef struct { int a; int b; } s_t;
+                  s_t s1 = { 0, };
+                  return s1.b;
+                }
+              ]],
+              [[]])],
+           [gl_cv_cc_nomfi_needed=no],
+           [gl_cv_cc_nomfi_needed=yes])
+         CFLAGS="$gl_save_CFLAGS"
+        ])
+    fi
+
+    dnl Next, check if -Werror -Wuninitialized is useful with the
+    dnl user's choice of $CFLAGS; some versions of gcc warn that it
+    dnl has no effect if -O is not also used
+    AC_CACHE_CHECK([whether -Wuninitialized is supported],
+      [gl_cv_cc_uninitialized_supported],
+      [gl_save_CFLAGS="$CFLAGS"
+       CFLAGS="$CFLAGS -Werror -Wuninitialized"
+       AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM([[]], [[]])],
+         [gl_cv_cc_uninitialized_supported=yes],
+         [gl_cv_cc_uninitialized_supported=no])
+       CFLAGS="$gl_save_CFLAGS"
+      ])
+
+  fi
+
+  # List all gcc warning categories.
+  # To compare this list to your installed GCC's, run this Bash command:
+  #
+  # comm -3 \
+  #  <((sed -n 's/^  *\(-[^ 0-9][^ ]*\) .*/\1/p' manywarnings.m4; \
+  #     awk '/^[^#]/ {print $1}' ../build-aux/gcc-warning.spec) | sort) \
+  #  <(LC_ALL=C gcc --help=warnings | sed -n 's/^  \(-[^ ]*\) .*/\1/p' | sort)
+
+  gl_manywarn_set=
+  for gl_manywarn_item in -fno-common \
+    -W \
+    -Waddress \
+    -Waggressive-loop-optimizations \
+    -Wall \
+    -Wattribute-alias \
+    -Wattributes \
+    -Wbad-function-cast \
+    -Wbool-compare \
+    -Wbool-operation \
+    -Wbuiltin-declaration-mismatch \
+    -Wbuiltin-macro-redefined \
+    -Wcast-align \
+    -Wcast-align=strict \
+    -Wcast-function-type \
+    -Wchar-subscripts \
+    -Wclobbered \
+    -Wcomment \
+    -Wcomments \
+    -Wcoverage-mismatch \
+    -Wcpp \
+    -Wdangling-else \
+    -Wdate-time \
+    -Wdeprecated \
+    -Wdeprecated-declarations \
+    -Wdesignated-init \
+    -Wdisabled-optimization \
+    -Wdiscarded-array-qualifiers \
+    -Wdiscarded-qualifiers \
+    -Wdiv-by-zero \
+    -Wdouble-promotion \
+    -Wduplicated-branches \
+    -Wduplicated-cond \
+    -Wduplicate-decl-specifier \
+    -Wempty-body \
+    -Wendif-labels \
+    -Wenum-compare \
+    -Wexpansion-to-defined \
+    -Wextra \
+    -Wformat-contains-nul \
+    -Wformat-extra-args \
+    -Wformat-nonliteral \
+    -Wformat-security \
+    -Wformat-signedness \
+    -Wformat-y2k \
+    -Wformat-zero-length \
+    -Wframe-address \
+    -Wfree-nonheap-object \
+    -Whsa \
+    -Wif-not-aligned \
+    -Wignored-attributes \
+    -Wignored-qualifiers \
+    -Wimplicit \
+    -Wimplicit-function-declaration \
+    -Wimplicit-int \
+    -Wincompatible-pointer-types \
+    -Winit-self \
+    -Winline \
+    -Wint-conversion \
+    -Wint-in-bool-context \
+    -Wint-to-pointer-cast \
+    -Winvalid-memory-model \
+    -Winvalid-pch \
+    -Wlogical-not-parentheses \
+    -Wlogical-op \
+    -Wmain \
+    -Wmaybe-uninitialized \
+    -Wmemset-elt-size \
+    -Wmemset-transposed-args \
+    -Wmisleading-indentation \
+    -Wmissing-attributes \
+    -Wmissing-braces \
+    -Wmissing-declarations \
+    -Wmissing-field-initializers \
+    -Wmissing-include-dirs \
+    -Wmissing-parameter-type \
+    -Wmissing-prototypes \
+    -Wmultichar \
+    -Wmultistatement-macros \
+    -Wnarrowing \
+    -Wnested-externs \
+    -Wnonnull \
+    -Wnonnull-compare \
+    -Wnull-dereference \
+    -Wodr \
+    -Wold-style-declaration \
+    -Wold-style-definition \
+    -Wopenmp-simd \
+    -Woverflow \
+    -Woverlength-strings \
+    -Woverride-init \
+    -Wpacked \
+    -Wpacked-bitfield-compat \
+    -Wpacked-not-aligned \
+    -Wparentheses \
+    -Wpointer-arith \
+    -Wpointer-compare \
+    -Wpointer-sign \
+    -Wpointer-to-int-cast \
+    -Wpragmas \
+    -Wpsabi \
+    -Wrestrict \
+    -Wreturn-local-addr \
+    -Wreturn-type \
+    -Wscalar-storage-order \
+    -Wsequence-point \
+    -Wshadow \
+    -Wshift-count-negative \
+    -Wshift-count-overflow \
+    -Wshift-negative-value \
+    -Wsizeof-array-argument \
+    -Wsizeof-pointer-div \
+    -Wsizeof-pointer-memaccess \
+    -Wstack-protector \
+    -Wstrict-aliasing \
+    -Wstrict-overflow \
+    -Wstrict-prototypes \
+    -Wstringop-truncation \
+    -Wsuggest-attribute=cold \
+    -Wsuggest-attribute=const \
+    -Wsuggest-attribute=format \
+    -Wsuggest-attribute=malloc \
+    -Wsuggest-attribute=noreturn \
+    -Wsuggest-attribute=pure \
+    -Wsuggest-final-methods \
+    -Wsuggest-final-types \
+    -Wswitch \
+    -Wswitch-bool \
+    -Wswitch-unreachable \
+    -Wsync-nand \
+    -Wsystem-headers \
+    -Wtautological-compare \
+    -Wtrampolines \
+    -Wtrigraphs \
+    -Wtype-limits \
+    -Wuninitialized \
+    -Wunknown-pragmas \
+    -Wunsafe-loop-optimizations \
+    -Wunused \
+    -Wunused-but-set-parameter \
+    -Wunused-but-set-variable \
+    -Wunused-function \
+    -Wunused-label \
+    -Wunused-local-typedefs \
+    -Wunused-macros \
+    -Wunused-parameter \
+    -Wunused-result \
+    -Wunused-value \
+    -Wunused-variable \
+    -Wvarargs \
+    -Wvariadic-macros \
+    -Wvector-operation-performance \
+    -Wvla \
+    -Wvolatile-register-var \
+    -Wwrite-strings \
+    \
+    ; do
+    gl_manywarn_set="$gl_manywarn_set $gl_manywarn_item"
+  done
+
+  # gcc --help=warnings outputs an unusual form for these options; list
+  # them here so that the above 'comm' command doesn't report a false match.
+  # Would prefer "min (PTRDIFF_MAX, SIZE_MAX)", but it must be a literal.
+  # Also, AC_COMPUTE_INT requires it to fit in a long; it is 2**63 on
+  # the only platforms where it does not fit in a long, so make that
+  # a special case.
+  AC_MSG_CHECKING([max safe object size])
+  AC_COMPUTE_INT([gl_alloc_max],
+    [LONG_MAX < (PTRDIFF_MAX < (size_t) -1 ? PTRDIFF_MAX : (size_t) -1)
+     ? -1
+     : PTRDIFF_MAX < (size_t) -1 ? (long) PTRDIFF_MAX : (long) (size_t) -1],
+    [[#include <limits.h>
+      #include <stddef.h>
+      #include <stdint.h>
+    ]],
+    [gl_alloc_max=2147483647])
+  case $gl_alloc_max in
+    -1) gl_alloc_max=9223372036854775807;;
+  esac
+  AC_MSG_RESULT([$gl_alloc_max])
+  gl_manywarn_set="$gl_manywarn_set -Walloc-size-larger-than=$gl_alloc_max"
+  gl_manywarn_set="$gl_manywarn_set -Warray-bounds=2"
+  gl_manywarn_set="$gl_manywarn_set -Wformat-overflow=2"
+  gl_manywarn_set="$gl_manywarn_set -Wformat-truncation=2"
+  gl_manywarn_set="$gl_manywarn_set -Wimplicit-fallthrough=5"
+  gl_manywarn_set="$gl_manywarn_set -Wnormalized=nfc"
+  gl_manywarn_set="$gl_manywarn_set -Wshift-overflow=2"
+  gl_manywarn_set="$gl_manywarn_set -Wstringop-overflow=2"
+  gl_manywarn_set="$gl_manywarn_set -Wunused-const-variable=2"
+  gl_manywarn_set="$gl_manywarn_set -Wvla-larger-than=4031"
+
+  # These are needed for older GCC versions.
+  if test -n "$GCC"; then
+    case `($CC --version) 2>/dev/null` in
+      'gcc (GCC) '[[0-3]].* | \
+      'gcc (GCC) '4.[[0-7]].*)
+        gl_manywarn_set="$gl_manywarn_set -fdiagnostics-show-option"
+        gl_manywarn_set="$gl_manywarn_set -funit-at-a-time"
+          ;;
+    esac
+  fi
+
+  # Disable specific options as needed.
+  if test "$gl_cv_cc_nomfi_needed" = yes; then
+    gl_manywarn_set="$gl_manywarn_set -Wno-missing-field-initializers"
+  fi
+
+  if test "$gl_cv_cc_uninitialized_supported" = no; then
+    gl_manywarn_set="$gl_manywarn_set -Wno-uninitialized"
+  fi
+
+  $1=$gl_manywarn_set
+
+  AC_LANG_POP([C])
+])
+
+# Specialization for _AC_LANG = C++.
+# Use of m4_defun rather than AC_DEFUN works around a bug in autoconf < 2.63b.
+m4_defun([gl_MANYWARN_ALL_GCC(C++)],
+[
+  gl_MANYWARN_ALL_GCC_CXX_IMPL([$1])
+])
diff --git a/m4/virt-viewer-warnings.m4 b/m4/virt-viewer-warnings.m4
new file mode 100644
index 0000000..4036b75
--- /dev/null
+++ b/m4/virt-viewer-warnings.m4
@@ -0,0 +1,159 @@
+dnl
+dnl Enable all known GCC compiler warnings, except for those
+dnl we can't yet cope with
+dnl
+AC_DEFUN([VIRT_VIEWER_COMPILE_WARNINGS],[
+    dnl ******************************
+    dnl More compiler warnings
+    dnl ******************************
+
+    AC_ARG_ENABLE([werror],
+                  AS_HELP_STRING([--enable-werror], [Use -Werror (if supported)]),
+                  [set_werror="$enableval"],
+                  [if test -d $srcdir/.git; then
+                     is_git_version=true
+                     set_werror=yes
+                   else
+                     set_werror=no
+                   fi])
+
+    # List of warnings that are not relevant / wanted
+
+    # Don't care about C++ compiler compat
+    dontwarn="$dontwarn -Wc++-compat"
+    dontwarn="$dontwarn -Wabi"
+    dontwarn="$dontwarn -Wdeprecated"
+    # Don't care about ancient C standard compat
+    dontwarn="$dontwarn -Wtraditional"
+    # Don't care about ancient C standard compat
+    dontwarn="$dontwarn -Wtraditional-conversion"
+    # Ignore warnings in /usr/include
+    dontwarn="$dontwarn -Wsystem-headers"
+    # Happy for compiler to add struct padding
+    dontwarn="$dontwarn -Wpadded"
+    # GCC very confused with -O2
+    dontwarn="$dontwarn -Wunreachable-code"
+    # Too many to deal with
+    dontwarn="$dontwarn -Wconversion"
+    # Too many to deal with
+    dontwarn="$dontwarn -Wsign-conversion"
+    # We need to use long long in many places
+    dontwarn="$dontwarn -Wlong-long"
+    # Not a problem since we don't use -fstrict-overflow
+    dontwarn="$dontwarn -Wstrict-overflow"
+    # Not a problem since we don't use -funsafe-loop-optimizations
+    dontwarn="$dontwarn -Wunsafe-loop-optimizations"
+    # gcc 4.4.6 complains this is C++ only; gcc 4.7.0 implies this from -Wall
+    dontwarn="$dontwarn -Wenum-compare"
+    # /usr/include/spice-1/spice/protocol.h triggers violations
+    dontwarn="$dontwarn -Wpacked"
+
+    # g_clear_object & G_ATOMIC_OP_USE_GCC_BUILTINS causes
+    # violations with this. XXX Fix glib ?
+    dontwarn="$dontwarn -Wbad-function-cast"
+
+    # Due to gutils.h bug in g_bit_storage
+    wantwarn="$wantwarn -Wno-sign-conversion"
+    wantwarn="$wantwarn -Wno-conversion"
+    # We can't enable this due to horrible spice_usb_device_get_description
+    # signature
+#    wantwarn="$wantwarn -Wno-format-nonliteral"
+
+    # Get all possible GCC warnings
+    gl_MANYWARN_ALL_GCC([maybewarn])
+
+    # Remove the ones we don't want, blacklisted earlier
+    gl_MANYWARN_COMPLEMENT([wantwarn], [$maybewarn], [$dontwarn])
+
+    # GNULIB uses '-W' (aka -Wextra) which includes a bunch of stuff.
+    # Unfortunately, this means you can't simply use '-Wsign-compare'
+    # with gl_MANYWARN_COMPLEMENT
+    # So we have -W enabled, and then have to explicitly turn off...
+    wantwarn="$wantwarn -Wno-sign-compare"
+
+    # GNULIB expects this to be part of -Wc++-compat, but we turn
+    # that one off, so we need to manually enable this again
+    wantwarn="$wantwarn -Wjump-misses-init"
+
+    # We do "bad" function casts all the time for event callbacks
+    wantwarn="$wantwarn -Wno-cast-function-type"
+
+    # GNULIB turns on -Wformat=2 which implies -Wformat-nonliteral,
+    # so we need to manually re-exclude it.
+    wantwarn="$wantwarn -Wno-format-nonliteral"
+
+    # This should be < 256 really. Currently we're down to 4096,
+    # but using 1024 bytes sized buffers (mostly for virStrerror)
+    # stops us from going down further
+    wantwarn="$wantwarn -Wframe-larger-than=4096"
+
+    # We want to allow use of comments to annotate switch fallthrough
+    wantwarn="$wantwarn -Wimplicit-fallthrough=2"
+
+    # Extra special flags
+    dnl -fstack-protector stuff passes gl_WARN_ADD with gcc
+    dnl on Mingw32, but fails when actually used
+    case $host in
+       aarch64-*-*)
+       dnl "error: -fstack-protector not supported for this target [-Werror]"
+       ;;
+       *-*-linux*)
+       dnl Prefer -fstack-protector-strong if it's available.
+       dnl There doesn't seem to be great overhead in adding
+       dnl -fstack-protector-all instead of -fstack-protector.
+       dnl
+       dnl We also don't need ssp-buffer-size with -all or -strong,
+       dnl since functions are protected regardless of buffer size.
+       dnl wantwarn="$wantwarn --param=ssp-buffer-size=4"
+       wantwarn="$wantwarn -fstack-protector-strong"
+       ;;
+       *-*-freebsd*)
+       dnl FreeBSD ships old gcc 4.2.1 which doesn't handle
+       dnl -fstack-protector-all well
+       wantwarn="$wantwarn -fstack-protector"
+
+       wantwarn="$wantwarn -Wno-unused-command-line-argument"
+       ;;
+    esac
+    wantwarn="$wantwarn -fexceptions"
+    wantwarn="$wantwarn -fasynchronous-unwind-tables"
+
+    # Need -fipa-pure-const in order to make -Wsuggest-attribute=pure
+    # fire even without -O.
+    wantwarn="$wantwarn -fipa-pure-const"
+    # We should eventually enable this, but right now there are at
+    # least 75 functions triggering warnings.
+    wantwarn="$wantwarn -Wno-suggest-attribute=pure"
+    wantwarn="$wantwarn -Wno-suggest-attribute=const"
+
+    if test "$set_werror" = "yes"
+    then
+      wantwarn="$wantwarn -Werror"
+    fi
+
+    # Check for $CC support of each warning
+    for w in $wantwarn; do
+      gl_WARN_ADD([$w])
+    done
+
+    case $host in
+        *-*-linux*)
+        dnl Fall back to -fstack-protector-all if -strong is not available
+        case $WARN_CFLAGS in
+        *-fstack-protector-strong*)
+        ;;
+        *)
+            gl_WARN_ADD(["-fstack-protector-all"])
+        ;;
+        esac
+        ;;
+    esac
+
+    AH_VERBATIM([FORTIFY_SOURCE],
+    [/* Enable compile-time and run-time bounds-checking, and some warnings,
+        without upsetting newer glibc. */
+     #if !defined _FORTIFY_SOURCE && defined __OPTIMIZE__ && __OPTIMIZE__
+     # define _FORTIFY_SOURCE 2
+     #endif
+    ])
+])
diff --git a/m4/warnings.m4 b/m4/warnings.m4
new file mode 100644
index 0000000..235cac6
--- /dev/null
+++ b/m4/warnings.m4
@@ -0,0 +1,115 @@
+# warnings.m4 serial 14
+dnl Copyright (C) 2008-2019 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Simon Josefsson
+
+# gl_AS_VAR_APPEND(VAR, VALUE)
+# ----------------------------
+# Provide the functionality of AS_VAR_APPEND if Autoconf does not have it.
+m4_ifdef([AS_VAR_APPEND],
+[m4_copy([AS_VAR_APPEND], [gl_AS_VAR_APPEND])],
+[m4_define([gl_AS_VAR_APPEND],
+[AS_VAR_SET([$1], [AS_VAR_GET([$1])$2])])])
+
+
+# gl_COMPILER_OPTION_IF(OPTION, [IF-SUPPORTED], [IF-NOT-SUPPORTED],
+#                       [PROGRAM = AC_LANG_PROGRAM()])
+# -----------------------------------------------------------------
+# Check if the compiler supports OPTION when compiling PROGRAM.
+#
+# The effects of this macro depend on the current language (_AC_LANG).
+AC_DEFUN([gl_COMPILER_OPTION_IF],
+[
+dnl FIXME: gl_Warn must be used unquoted until we can assume Autoconf
+dnl 2.64 or newer.
+AS_VAR_PUSHDEF([gl_Warn], [gl_cv_warn_[]_AC_LANG_ABBREV[]_$1])dnl
+AS_VAR_PUSHDEF([gl_Flags], [_AC_LANG_PREFIX[]FLAGS])dnl
+AS_LITERAL_IF([$1],
+  [m4_pushdef([gl_Positive], m4_bpatsubst([$1], [^-Wno-], [-W]))],
+  [gl_positive="$1"
+case $gl_positive in
+  -Wno-*) gl_positive=-W`expr "X$gl_positive" : 'X-Wno-\(.*\)'` ;;
+esac
+m4_pushdef([gl_Positive], [$gl_positive])])dnl
+AC_CACHE_CHECK([whether _AC_LANG compiler handles $1], m4_defn([gl_Warn]), [
+  gl_save_compiler_FLAGS="$gl_Flags"
+  gl_AS_VAR_APPEND(m4_defn([gl_Flags]),
+    [" $gl_unknown_warnings_are_errors ]m4_defn([gl_Positive])["])
+  AC_LINK_IFELSE([m4_default([$4], [AC_LANG_PROGRAM([])])],
+                 [AS_VAR_SET(gl_Warn, [yes])],
+                 [AS_VAR_SET(gl_Warn, [no])])
+  gl_Flags="$gl_save_compiler_FLAGS"
+])
+AS_VAR_IF(gl_Warn, [yes], [$2], [$3])
+m4_popdef([gl_Positive])dnl
+AS_VAR_POPDEF([gl_Flags])dnl
+AS_VAR_POPDEF([gl_Warn])dnl
+])
+
+# gl_UNKNOWN_WARNINGS_ARE_ERRORS
+# ------------------------------
+# Clang doesn't complain about unknown warning options unless one also
+# specifies -Wunknown-warning-option -Werror.  Detect this.
+#
+# The effects of this macro depend on the current language (_AC_LANG).
+AC_DEFUN([gl_UNKNOWN_WARNINGS_ARE_ERRORS],
+[_AC_LANG_DISPATCH([$0], _AC_LANG, $@)])
+
+# Specialization for _AC_LANG = C. This macro can be AC_REQUIREd.
+# Use of m4_defun rather than AC_DEFUN works around a bug in autoconf < 2.63b.
+m4_defun([gl_UNKNOWN_WARNINGS_ARE_ERRORS(C)],
+[
+  AC_LANG_PUSH([C])
+  gl_UNKNOWN_WARNINGS_ARE_ERRORS_IMPL
+  AC_LANG_POP([C])
+])
+
+# Specialization for _AC_LANG = C++. This macro can be AC_REQUIREd.
+# Use of m4_defun rather than AC_DEFUN works around a bug in autoconf < 2.63b.
+m4_defun([gl_UNKNOWN_WARNINGS_ARE_ERRORS(C++)],
+[
+  AC_LANG_PUSH([C++])
+  gl_UNKNOWN_WARNINGS_ARE_ERRORS_IMPL
+  AC_LANG_POP([C++])
+])
+
+# Specialization for _AC_LANG = Objective C. This macro can be AC_REQUIREd.
+# Use of m4_defun rather than AC_DEFUN works around a bug in autoconf < 2.63b.
+m4_defun([gl_UNKNOWN_WARNINGS_ARE_ERRORS(Objective C)],
+[
+  AC_LANG_PUSH([Objective C])
+  gl_UNKNOWN_WARNINGS_ARE_ERRORS_IMPL
+  AC_LANG_POP([Objective C])
+])
+
+AC_DEFUN([gl_UNKNOWN_WARNINGS_ARE_ERRORS_IMPL],
+[gl_COMPILER_OPTION_IF([-Werror -Wunknown-warning-option],
+   [gl_unknown_warnings_are_errors='-Wunknown-warning-option -Werror'],
+   [gl_unknown_warnings_are_errors=])])
+
+# gl_WARN_ADD(OPTION, [VARIABLE = WARN_CFLAGS/WARN_CXXFLAGS],
+#             [PROGRAM = AC_LANG_PROGRAM()])
+# -----------------------------------------------------------
+# Adds parameter to WARN_CFLAGS/WARN_CXXFLAGS if the compiler supports it
+# when compiling PROGRAM.  For example, gl_WARN_ADD([-Wparentheses]).
+#
+# If VARIABLE is a variable name, AC_SUBST it.
+#
+# The effects of this macro depend on the current language (_AC_LANG).
+AC_DEFUN([gl_WARN_ADD],
+[AC_REQUIRE([gl_UNKNOWN_WARNINGS_ARE_ERRORS(]_AC_LANG[)])
+gl_COMPILER_OPTION_IF([$1],
+  [gl_AS_VAR_APPEND(m4_if([$2], [], [[WARN_]_AC_LANG_PREFIX[FLAGS]], [[$2]]), [" $1"])],
+  [],
+  [$3])
+m4_ifval([$2],
+         [AS_LITERAL_IF([$2], [AC_SUBST([$2])])],
+         [AC_SUBST([WARN_]_AC_LANG_PREFIX[FLAGS])])dnl
+])
+
+# Local Variables:
+# mode: autoconf
+# End:
diff --git a/prepare-release.sh b/prepare-release.sh
index c2fbfdb..11e6abb 100755
--- a/prepare-release.sh
+++ b/prepare-release.sh
@@ -14,7 +14,7 @@ mkdir build
 cd build
 
 ../autogen.sh --prefix=$INSTALL_ROOT \
-    --enable-compile-warnings=error
+    --enable-werror
 
 make
 make install
-- 
2.20.1




More information about the virt-tools-list mailing list