[Mesa-dev] [PATCH 01/24] configure.ac: Add CFLAG -Wno-missing-field-initializers (v3)

[Gert Wollny]

This warning is misleading: When a struct is partially initialized without
assigning to the structure members by name, then the remaining fields
will be zeroed out, and this warning will be issued (if enabled). If, on the
other hand, the partial initialization is done by assigning to named members,
the remaining structure elements may hold random data, but the warning is not
issued. Since in Mesa the first approach to initialize structure elements is
used very often, and it is usually assumed that the remaining elements are
zeroed out, heeding this warning would be counter-productive.

v2: - add -Wno-missing-field-initializers to meson-build
    - fix empty line error
    (both Eric Engestrom)

v3: * check for -Wmissing-field-initializers warning and then disable it
      because gcc and clang always accept -Wno-* (Dylan Baker)
    * Also disable this warning for C++

Reviewed-by: Marek Olšák <marek.olsak at amd.com> (v1)
Reviewed-by: Emil Velikov <emil.velikov at collabora.com> (v2)
Signed-off-by: Gert Wollny <gert.wollny at collabora.com>
---
 configure.ac |  4 ++++
 meson.build  | 11 +++++++----
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/configure.ac b/configure.ac
index 75ee1a7c01..6a9e56f974 100644
--- a/configure.ac
+++ b/configure.ac
@@ -302,7 +302,10 @@ AX_CHECK_COMPILE_FLAG([-Wall],                                 [CFLAGS="$CFLAGS
 AX_CHECK_COMPILE_FLAG([-Werror=implicit-function-declaration], [CFLAGS="$CFLAGS -Werror=implicit-function-declaration"])
 AX_CHECK_COMPILE_FLAG([-Werror=missing-prototypes],            [CFLAGS="$CFLAGS -Werror=missing-prototypes"])
 AX_CHECK_COMPILE_FLAG([-Wmissing-prototypes],                  [CFLAGS="$CFLAGS -Wmissing-prototypes"])
+dnl Dylan Baker: gcc and clang always accepr -Wno-*, hence check for the original warning, then set the no-* flag
+AX_CHECK_COMPILE_FLAG([-Wmissing-field-initializers],          [CFLAGS="$CFLAGS -Wno-missing-field-initializers"])
 AX_CHECK_COMPILE_FLAG([-fno-math-errno],                       [CFLAGS="$CFLAGS -fno-math-errno"])
+
 AX_CHECK_COMPILE_FLAG([-fno-trapping-math],                    [CFLAGS="$CFLAGS -fno-trapping-math"])
 AX_CHECK_COMPILE_FLAG([-fvisibility=hidden],                   [VISIBILITY_CFLAGS="-fvisibility=hidden"])
 
@@ -314,6 +317,7 @@ AX_CHECK_COMPILE_FLAG([-Wall],                                 [CXXFLAGS="$CXXFL
 AX_CHECK_COMPILE_FLAG([-fno-math-errno],                       [CXXFLAGS="$CXXFLAGS -fno-math-errno"])
 AX_CHECK_COMPILE_FLAG([-fno-trapping-math],                    [CXXFLAGS="$CXXFLAGS -fno-trapping-math"])
 AX_CHECK_COMPILE_FLAG([-fvisibility=hidden],                   [VISIBILITY_CXXFLAGS="-fvisibility=hidden"])
+AX_CHECK_COMPILE_FLAG([-Wmissing-field-initializers],          [CFLAGS="$CFLAGS -Wno-missing-field-initializers"])
 AC_LANG_POP([C++])
 
 # Flags to help ensure that certain portions of the code -- and only those
diff --git a/meson.build b/meson.build
index 160bbfa30b..668fa38328 100644
--- a/meson.build
+++ b/meson.build
@@ -760,12 +760,15 @@ endforeach
 
 # For some reason, the test for -Wno-foo always succeeds with gcc, even if the
 # option is not supported. Hence, check for -Wfoo instead.
-if cpp.has_argument('-Wnon-virtual-dtor')
-  cpp_args += '-Wno-non-virtual-dtor'
-endif
+
+foreach a : ['non-virtual-dtor', 'missing-field-initializers']
+  if cpp.has_argument('-W' + a)
+    cpp_args += '-Wno-' + a
+  endif
+endforeach
 
 no_override_init_args = []
-foreach a : ['override-init', 'initializer-overrides']
+foreach a : ['override-init', 'initializer-overrides', 'missing-field-initializers']
   if cc.has_argument('-W' + a)
     no_override_init_args += '-Wno-' + a
   endif
-- 
2.17.1