--enable-gcc-warnings now uses -Wjump-misses-init

When configuring with --enable-gcc-warnings, also enable
-Wjump-misses-init, as it’s confusing to use a goto to skip over
an initialization.  Fix the few places in the code that run afoul
of this warning.
* configure.ac (WERROR_CFLAGS): Add -Wjump-misses-init.
* src/doc.c (Fsubstitute_command_keys):
* src/image.c (svg_load_image):
* src/regex.c (re_match_2_internal):
* src/xdisp.c (redisplay_internal, redisplay_window):
Don’t jump over initialization.

4 files changed, 89 insertions, 95 deletions

diff --git a/src/doc.c b/src/doc.c
index a9273f05809..ae807910316 100644
--- a/src/doc.c
+++ b/src/doc.c
@@ -865,16 +865,14 @@ Otherwise, return a new string.  */)
          \<foo> just sets the keymap used for \[cmd].  */
       else if (strp[0] == '\\' && (strp[1] == '{' || strp[1] == '<'))
         {
-          struct buffer *oldbuf;
-          ptrdiff_t start_idx;
+         {
           /* This is for computing the SHADOWS arg for describe_map_tree.  */
           Lisp_Object active_maps = Fcurrent_active_maps (Qnil, Qnil);
-          Lisp_Object earlier_maps;
           ptrdiff_t count = SPECPDL_INDEX ();
 
           strp += 2;            /* skip \{ or \< */
           start = strp;
-          start_idx = start - SDATA (string);
+          ptrdiff_t start_idx = start - SDATA (string);
 
           while ((strp - SDATA (string) < SBYTES (string))
                  && *strp != '}' && *strp != '>')
@@ -904,7 +902,7 @@ Otherwise, return a new string.  */)
             }
 
           /* Now switch to a temp buffer.  */
-          oldbuf = current_buffer;
+          struct buffer *oldbuf = current_buffer;
           set_buffer_internal (XBUFFER (Vprin1_to_string_buffer));
           /* This is for an unusual case where some after-change
              function uses 'format' or 'prin1' or something else that
@@ -929,7 +927,8 @@ Otherwise, return a new string.  */)
             {
               /* Get the list of active keymaps that precede this one.
                  If this one's not active, get nil.  */
-              earlier_maps = Fcdr (Fmemq (tem, Freverse (active_maps)));
+              Lisp_Object earlier_maps
+                = Fcdr (Fmemq (tem, Freverse (active_maps)));
               describe_map_tree (tem, 1, Fnreverse (earlier_maps),
                                  Qnil, 0, 1, 0, 0, 1);
             }
@@ -937,6 +936,7 @@ Otherwise, return a new string.  */)
           Ferase_buffer ();
           set_buffer_internal (oldbuf);
           unbind_to (count, Qnil);
+         }
 
         subst_string:
           start = SDATA (tem);
diff --git a/src/image.c b/src/image.c
index 9ba1a7972f0..aa45b001d30 100644
--- a/src/image.c
+++ b/src/image.c
@@ -9257,8 +9257,8 @@ svg_load_image (struct frame *f,         /* Pointer to emacs frame structure.  *
   eassert (gdk_pixbuf_get_has_alpha (pixbuf));
   eassert (gdk_pixbuf_get_bits_per_sample (pixbuf) == 8);
 
-#ifdef USE_CAIRO
   {
+#ifdef USE_CAIRO
     unsigned char *data = (unsigned char *) xmalloc (width*height*4);
     uint32_t bgcolor = get_spec_bg_or_alpha_as_argb (img, f);
 
@@ -9284,82 +9284,77 @@ svg_load_image (struct frame *f,         /* Pointer to emacs frame structure.  *
 
     create_cairo_image_surface (img, data, width, height);
     g_object_unref (pixbuf);
-  }
 #else
-  /* Try to create a x pixmap to hold the svg pixmap.  */
-  XImagePtr ximg;
-  if (!image_create_x_image_and_pixmap (f, img, width, height, 0, &ximg, 0))
-    {
-      g_object_unref (pixbuf);
-      return 0;
-    }
+    /* Try to create a x pixmap to hold the svg pixmap.  */
+    XImagePtr ximg;
+    if (!image_create_x_image_and_pixmap (f, img, width, height, 0, &ximg, 0))
+      {
+        g_object_unref (pixbuf);
+        return 0;
+      }
 
-  init_color_table ();
+    init_color_table ();
 
-  /* Handle alpha channel by combining the image with a background
-     color.  */
-  XColor background;
-  Lisp_Object specified_bg = image_spec_value (img->spec, QCbackground, NULL);
-  if (!STRINGP (specified_bg)
-      || !x_defined_color (f, SSDATA (specified_bg), &background, 0))
-    x_query_frame_background_color (f, &background);
-
-  /* SVG pixmaps specify transparency in the last byte, so right
-     shift 8 bits to get rid of it, since emacs doesn't support
-     transparency.  */
-  background.red   >>= 8;
-  background.green >>= 8;
-  background.blue  >>= 8;
-
-  /* This loop handles opacity values, since Emacs assumes
-     non-transparent images.  Each pixel must be "flattened" by
-     calculating the resulting color, given the transparency of the
-     pixel, and the image background color.  */
-  for (int y = 0; y < height; ++y)
-    {
-      for (int x = 0; x < width; ++x)
-        {
-          int red;
-          int green;
-          int blue;
-          int opacity;
-
-          red     = *pixels++;
-          green   = *pixels++;
-          blue    = *pixels++;
-          opacity = *pixels++;
-
-          red   = ((red * opacity)
-                   + (background.red * ((1 << 8) - opacity)));
-          green = ((green * opacity)
-                   + (background.green * ((1 << 8) - opacity)));
-          blue  = ((blue * opacity)
-                   + (background.blue * ((1 << 8) - opacity)));
-
-          XPutPixel (ximg, x, y, lookup_rgb_color (f, red, green, blue));
-        }
+    /* Handle alpha channel by combining the image with a background
+       color.  */
+    XColor background;
+    Lisp_Object specified_bg = image_spec_value (img->spec, QCbackground, NULL);
+    if (!STRINGP (specified_bg)
+        || !x_defined_color (f, SSDATA (specified_bg), &background, 0))
+      x_query_frame_background_color (f, &background);
+
+    /* SVG pixmaps specify transparency in the last byte, so right
+       shift 8 bits to get rid of it, since emacs doesn't support
+       transparency.  */
+    background.red   >>= 8;
+    background.green >>= 8;
+    background.blue  >>= 8;
+
+    /* This loop handles opacity values, since Emacs assumes
+       non-transparent images.  Each pixel must be "flattened" by
+       calculating the resulting color, given the transparency of the
+       pixel, and the image background color.  */
+    for (int y = 0; y < height; ++y)
+      {
+        for (int x = 0; x < width; ++x)
+          {
+            int red     = *pixels++;
+            int green   = *pixels++;
+            int blue    = *pixels++;
+            int opacity = *pixels++;
+
+            red   = ((red * opacity)
+                     + (background.red * ((1 << 8) - opacity)));
+            green = ((green * opacity)
+                     + (background.green * ((1 << 8) - opacity)));
+            blue  = ((blue * opacity)
+                     + (background.blue * ((1 << 8) - opacity)));
+
+            XPutPixel (ximg, x, y, lookup_rgb_color (f, red, green, blue));
+          }
 
-      pixels += rowstride - 4 * width;
-    }
+        pixels += rowstride - 4 * width;
+      }
 
 #ifdef COLOR_TABLE_SUPPORT
-  /* Remember colors allocated for this image.  */
-  img->colors = colors_in_color_table (&img->ncolors);
-  free_color_table ();
+    /* Remember colors allocated for this image.  */
+    img->colors = colors_in_color_table (&img->ncolors);
+    free_color_table ();
 #endif /* COLOR_TABLE_SUPPORT */
 
-  g_object_unref (pixbuf);
+    g_object_unref (pixbuf);
 
-  img->width  = width;
-  img->height = height;
+    img->width  = width;
+    img->height = height;
 
-  /* Maybe fill in the background field while we have ximg handy.
-     Casting avoids a GCC warning.  */
-  IMAGE_BACKGROUND (img, f, (XImagePtr_or_DC)ximg);
+    /* Maybe fill in the background field while we have ximg handy.
+       Casting avoids a GCC warning.  */
+    IMAGE_BACKGROUND (img, f, (XImagePtr_or_DC)ximg);
 
-  /* Put ximg into the image.  */
-  image_put_x_image (f, img, ximg, 0);
+    /* Put ximg into the image.  */
+    image_put_x_image (f, img, ximg, 0);
 #endif /* ! USE_CAIRO */
+  }
 
   return 1;
 
diff --git a/src/regex.c b/src/regex.c
index 164eb4612ae..d5c58aeaf8b 100644
--- a/src/regex.c
+++ b/src/regex.c
@@ -5140,8 +5140,6 @@ re_match_2_internal (struct re_pattern_buffer *bufp, const_re_char *string1,
 
       if (p == pend)
         {
-          ptrdiff_t dcnt;
-
           /* End of pattern means we might have succeeded.  */
           DEBUG_PRINT ("end of pattern ... ");
 
@@ -5149,19 +5147,22 @@ re_match_2_internal (struct re_pattern_buffer *bufp, const_re_char *string1,
              longest match, try backtracking.  */
           if (d != end_match_2)
             {
-              /* 1 if this match ends in the same string (string1 or string2)
-                 as the best previous match.  */
-              boolean same_str_p = (FIRST_STRING_P (match_end)
-                                    == FIRST_STRING_P (d));
-              /* 1 if this match is the best seen so far.  */
-              boolean best_match_p;
-
-              /* AIX compiler got confused when this was combined
-                 with the previous declaration.  */
-              if (same_str_p)
-                best_match_p = d > match_end;
-              else
-                best_match_p = !FIRST_STRING_P (d);
+              /* True if this match is the best seen so far.  */
+              bool best_match_p;
+
+              {
+                /* True if this match ends in the same string (string1
+                   or string2) as the best previous match.  */
+                bool same_str_p = (FIRST_STRING_P (match_end)
+                                   == FIRST_STRING_P (d));
+
+                /* AIX compiler got confused when this was combined
+                   with the previous declaration.  */
+                if (same_str_p)
+                  best_match_p = d > match_end;
+                else
+                  best_match_p = !FIRST_STRING_P (d);
+              }
 
               DEBUG_PRINT ("backtracking.\n");
 
@@ -5290,7 +5291,7 @@ re_match_2_internal (struct re_pattern_buffer *bufp, const_re_char *string1,
                        nfailure_points_pushed - nfailure_points_popped);
           DEBUG_PRINT ("%u registers pushed.\n", num_regs_pushed);
 
-          dcnt = POINTER_TO_OFFSET (d) - pos;
+          ptrdiff_t dcnt = POINTER_TO_OFFSET (d) - pos;
 
           DEBUG_PRINT ("Returning %td from re_match_2.\n", dcnt);
 
diff --git a/src/xdisp.c b/src/xdisp.c
index 4330f106002..acb275481ad 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -13989,9 +13989,6 @@ redisplay_internal (void)
     }
   else if (FRAME_VISIBLE_P (sf) && !FRAME_OBSCURED_P (sf))
     {
-      Lisp_Object mini_window = FRAME_MINIBUF_WINDOW (sf);
-      struct frame *mini_frame;
-
       displayed_buffer = XBUFFER (XWINDOW (selected_window)->contents);
       /* Use list_of_error, not Qerror, so that
          we catch only errors and don't run the debugger.  */
@@ -13999,8 +13996,8 @@ redisplay_internal (void)
                                  list_of_error,
                                  redisplay_window_error);
       if (update_miniwindow_p)
-        internal_condition_case_1 (redisplay_window_1, mini_window,
-                                   list_of_error,
+        internal_condition_case_1 (redisplay_window_1,
+                                   FRAME_MINIBUF_WINDOW (sf), list_of_error,
                                    redisplay_window_error);
 
       /* Compare desired and current matrices, perform output.  */
@@ -14050,8 +14047,8 @@ redisplay_internal (void)
          have put text on a frame other than the selected one, so the
          above call to update_frame would not have caught it.  Catch
          it here.  */
-      mini_window = FRAME_MINIBUF_WINDOW (sf);
-      mini_frame = XFRAME (WINDOW_FRAME (XWINDOW (mini_window)));
+      Lisp_Object mini_window = FRAME_MINIBUF_WINDOW (sf);
+      struct frame *mini_frame = XFRAME (WINDOW_FRAME (XWINDOW (mini_window)));
 
       if (mini_frame != sf && FRAME_WINDOW_P (mini_frame))
         {
@@ -16041,6 +16038,7 @@ redisplay_window (Lisp_Object window, bool just_this_one_p)
   bool last_line_misfit = false;
   ptrdiff_t beg_unchanged, end_unchanged;
   int frame_line_height;
+  bool use_desired_matrix;
 
   SET_TEXT_POS (lpoint, PT, PT_BYTE);
   opoint = lpoint;
@@ -16763,7 +16761,7 @@ redisplay_window (Lisp_Object window, bool just_this_one_p)
   startp = run_window_scroll_functions (window, it.current.pos);
 
   /* Redisplay the window.  */
-  bool use_desired_matrix = false;
+  use_desired_matrix = false;
   if (!current_matrix_up_to_date_p
       || windows_or_buffers_changed
       || f->cursor_type_changed