Enable many more compiler warnings

* m4/manywarnings.m4m, m4/warnings.m4: Import GNULIB warnings
  modules
* m4/spice-compile-warnings.m4: Define SPICE_COMPILE_WARNINGS
* configure.ac: Replace compile warning check with a call to
  SPICE_COMPILE_WARNINGS
* client/Makefile.am: Use WARN_CXXFLAGS instead of WARN_CFLAGS

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

1 files changed, 162 insertions, 0 deletions

diff --git a/m4/spice-compile-warnings.m4 b/m4/spice-compile-warnings.m4
new file mode 100644
index 00000000..8de2ffd0
--- /dev/null
+++ b/m4/spice-compile-warnings.m4
@@ -0,0 +1,162 @@
+dnl
+dnl Enable all known GCC compiler warnings, except for those
+dnl we can't yet cope with
+dnl
+AC_DEFUN([SPICE_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="$dontwarn -Wunreachable-code"
+
+
+    dontwarn="$dontwarn -Wconversion"
+    dontwarn="$dontwarn -Wsign-conversion"
+    dontwarn="$dontwarn -Wvla"
+    dontwarn="$dontwarn -Wundef"
+    dontwarn="$dontwarn -Wcast-qual"
+    dontwarn="$dontwarn -Wlong-long"
+    dontwarn="$dontwarn -Wswitch-default"
+    dontwarn="$dontwarn -Wswitch-enum"
+    dontwarn="$dontwarn -Wstrict-overflow"
+    dontwarn="$dontwarn -Wunsafe-loop-optimizations"
+    dontwarn="$dontwarn -Wformat-nonliteral"
+    dontwarn="$dontwarn -Wfloat-equal"
+    dontwarn="$dontwarn -Wdeclaration-after-statement"
+    dontwarn="$dontwarn -Wcast-qual"
+    dontwarn="$dontwarn -Wconversion"
+    dontwarn="$dontwarn -Wsign-conversion"
+    dontwarn="$dontwarn -Wpacked"
+    dontwarn="$dontwarn -Wunused-macros"
+    dontwarn="$dontwarn -Woverlength-strings"
+    dontwarn="$dontwarn -Wstack-protector"
+    dontwarn="$dontwarn -Winline"
+    dontwarn="$dontwarn -Wbad-function-cast"
+    dontwarn="$dontwarn -Wshadow"
+
+    # We want to enable thse, but need to sort out the
+    # decl mess with  gtk/generated_*.c
+    dontwarn="$dontwarn -Wmissing-prototypes"
+    dontwarn="$dontwarn -Wmissing-declarations"
+
+    # Stuff that C++ won't allow. Turn them back on later
+    dontwarn="$dontwarn -Waggregate-return"
+    dontwarn="$dontwarn -Wstrict-prototypes"
+    dontwarn="$dontwarn -Wold-style-definition"
+    dontwarn="$dontwarn -Wnested-externs"
+    dontwarn="$dontwarn -Wformat-zero-length"
+    dontwarn="$dontwarn -Wpointer-to-int-cast"
+    dontwarn="$dontwarn -Wjump-misses-init"
+
+    # Issues in x11/platform_utils.cpp prevent us turning this on
+    dontwarn="$dontwarn -Wmissing-format-attribute"
+
+    # 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])
+
+    # Check for $CC support of each warning
+    for w in $wantwarn; do
+      gl_WARN_ADD([$w])
+    done
+
+    # 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...
+    gl_WARN_ADD([-Wno-sign-compare])
+    gl_WARN_ADD([-Wno-unused-parameter])
+    # We can't enable this due to horrible spice_usb_device_get_description
+    # signature
+    gl_WARN_ADD([-Wno-format-nonliteral])
+    # CEGui headers cause violation of this
+    gl_WARN_ADD([-Wno-ignored-qualifiers])
+
+
+
+
+    # GNULIB turns on -Wformat=2 which implies -Wformat-nonliteral,
+    # so we need to manually re-exclude it.
+    gl_WARN_ADD([-Wno-format-nonliteral])
+
+    # This should be < 1024 really. pixman_utils is the blackspot
+    # preventing lower usage
+    gl_WARN_ADD([-Wframe-larger-than=20460])
+
+    # Use improved glibc headers
+    AC_DEFINE([_FORTIFY_SOURCE], [2],
+      [enable compile-time and run-time bounds-checking, and some warnings])
+
+    # Extra special flags
+    dnl -fstack-protector stuff passes gl_WARN_ADD with gcc
+    dnl on Mingw32, but fails when actually used
+    case $host in
+       *-*-linux*)
+       dnl Fedora only uses -fstack-protector, but doesn't seem to
+       dnl be great overhead in adding -fstack-protector-all instead
+       dnl gl_WARN_ADD([-fstack-protector])
+       gl_WARN_ADD([-fstack-protector-all])
+       gl_WARN_ADD([--param=ssp-buffer-size=4])
+       ;;
+    esac
+    gl_WARN_ADD([-fexceptions])
+    gl_WARN_ADD([-fasynchronous-unwind-tables])
+    gl_WARN_ADD([-fdiagnostics-show-option])
+    gl_WARN_ADD([-funit-at-a-time])
+
+    # Need -fipa-pure-const in order to make -Wsuggest-attribute=pure
+    # fire even without -O.
+    gl_WARN_ADD([-fipa-pure-const])
+
+    # We should eventually enable this, but right now there are at
+    # least 75 functions triggering warnings.
+    gl_WARN_ADD([-Wno-suggest-attribute=pure])
+    gl_WARN_ADD([-Wno-suggest-attribute=const])
+
+    if test "$set_werror" = "yes"
+    then
+      gl_WARN_ADD([-Werror])
+    fi
+    WARN_CXXFLAGS=$WARN_CFLAGS
+    AC_SUBST([WARN_CXXFLAGS])
+
+    # These are C-only warnings
+    gl_WARN_ADD([-Waggregate-return])
+    gl_WARN_ADD([-Wstrict-prototypes])
+    gl_WARN_ADD([-Wold-style-definition])
+    gl_WARN_ADD([-Wnested-externs])
+    gl_WARN_ADD([-Wformat-zero-length])
+    gl_WARN_ADD([-Wpointer-to-int-cast])
+    gl_WARN_ADD([-Wjump-misses-init])
+
+    WARN_LDFLAGS=$WARN_CFLAGS
+    AC_SUBST([WARN_CFLAGS])
+    AC_SUBST([WARN_LDFLAGS])
+])