Re: Suspicious warning in W64 build

[Fabrice Popineau]

2017-09-15 11:12 GMT+02:00 Eli Zaretskii <address@hidden>:

> From: Fabrice Popineau <address@hiddenlec.fr>
> Date: Fri, 15 Sep 2017 08:55:06 +0200
> Cc: Emacs developers <address@hidden>
>
>  # define pDWP "16llx"
>  ^
>
>  Should these be using the ptrdiff_t formatter pD from lisp.h ?
>
> I'd rather cast the values to "long long unsigned int" as these values are assumed to be positive,
> and would be meaningless if printed in decimal.

That's what I did.

That's ok and no more warnings now.

 

> There are also a bunch of warnings in dispnew.c:adjust_glyph_matrix()
> because the w parameter could be NULL. Actually, some parts of the code
> are protected with if (w) { ... } but much more than those ones assume that
> w is not NULL.

That's because they really cannot be NULL at that point.  GCC 7
doesn't really understand the code, so it shouldn't emit these
warnings, if it wants them to be useful.

> I wonder if the whole function should not just return if w is NULL.

No!

Ok. I see your eassert() added at this point.

But clearly there is a problem with GCC 7, because it doesn't understand

the implications of this eassert() :

  CC       dispnew.o

../../emacs/src/dispnew.c: In function 'adjust_frame_glyphs':

../../emacs/src/dispnew.c:392:14: warning: null pointer dereference [-Wnull-dereference]

       left = margin_glyphs_to_reserve (w, dim.width, w->left_margin_cols);

              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

../../emacs/src/dispnew.c:322:11: warning: null pointer dereference [-Wnull-dereference]

       int width = w->total_cols;

           ^~~~~

../../emacs/src/dispnew.c:393:15: warning: null pointer dereference [-Wnull-dereference]

       right = margin_glyphs_to_reserve (w, dim.width, w->right_margin_cols);

               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

../../emacs/src/dispnew.c:322:11: warning: null pointer dereference [-Wnull-dereference]

       int width = w->total_cols;

           ^~~~~

In file included from ../../emacs/src/frame.h:23:0,

                 from ../../emacs/src/dispnew.c:34:

../../emacs/src/window.h:651:38: warning: null pointer dereference [-Wnull-dereference]

 #define WINDOW_LEFT_PIXEL_EDGE(W) (W)->pixel_left

                                   ~~~^~~

../../emacs/src/dispnew.c:401:36: note: in expansion of macro 'WINDOW_LEFT_PIXEL_EDGE'

    && matrix->window_pixel_left == WINDOW_LEFT_PIXEL_EDGE (w)

                                    ^~~~~~~~~~~~~~~~~~~~~~

../../emacs/src/window.h:660:37: warning: null pointer dereference [-Wnull-dereference]

 #define WINDOW_TOP_PIXEL_EDGE(W) (W)->pixel_top

                                  ~~~^~~

../../emacs/src/dispnew.c:402:35: note: in expansion of macro 'WINDOW_TOP_PIXEL_EDGE'

    && matrix->window_pixel_top == WINDOW_TOP_PIXEL_EDGE (w)

                                   ^~~~~~~~~~~~~~~~~~~~~

../../emacs/src/dispnew.c:404:34: warning: null pointer dereference [-Wnull-dereference]

    && matrix->window_vscroll == w->vscroll

                                 ~^~~~~~~~~

../../emacs/src/dispnew.c:392:14: warning: null pointer dereference [-Wnull-dereference]

       left = margin_glyphs_to_reserve (w, dim.width, w->left_margin_cols);

              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

../../emacs/src/dispnew.c:322:11: warning: null pointer dereference [-Wnull-dereference]

       int width = w->total_cols;

           ^~~~~

../../emacs/src/dispnew.c:393:15: warning: null pointer dereference [-Wnull-dereference]

       right = margin_glyphs_to_reserve (w, dim.width, w->right_margin_cols);

               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

../../emacs/src/dispnew.c:322:11: warning: null pointer dereference [-Wnull-dereference]

       int width = w->total_cols;

           ^~~~~

In file included from ../../emacs/src/frame.h:23:0,

                 from ../../emacs/src/dispnew.c:34:

../../emacs/src/window.h:651:38: warning: null pointer dereference [-Wnull-dereference]

 #define WINDOW_LEFT_PIXEL_EDGE(W) (W)->pixel_left

                                   ~~~^~~

../../emacs/src/dispnew.c:401:36: note: in expansion of macro 'WINDOW_LEFT_PIXEL_EDGE'

    && matrix->window_pixel_left == WINDOW_LEFT_PIXEL_EDGE (w)

                                    ^~~~~~~~~~~~~~~~~~~~~~

../../emacs/src/window.h:660:37: warning: null pointer dereference [-Wnull-dereference]

 #define WINDOW_TOP_PIXEL_EDGE(W) (W)->pixel_top

                                  ~~~^~~

../../emacs/src/dispnew.c:402:35: note: in expansion of macro 'WINDOW_TOP_PIXEL_EDGE'

    && matrix->window_pixel_top == WINDOW_TOP_PIXEL_EDGE (w)

                                   ^~~~~~~~~~~~~~~~~~~~~

../../emacs/src/dispnew.c:404:34: warning: null pointer dereference [-Wnull-dereference]

    && matrix->window_vscroll == w->vscroll

                                 ~^~~~~~~~~

cc1.exe: warning: null pointer dereference [-Wnull-dereference]

cc1.exe: warning: null pointer dereference [-Wnull-dereference]

--

Fabrice