[Emacs-diffs] emacs-25 1985e9d 2/2: Port --enable-gcc-warnings to GCC 7

[Paul Eggert]

branch: emacs-25
commit 1985e9dcbb4ebc4df651decfdad72fae7cff3ed3
Author: Paul Eggert <address@hidden>
Commit: Paul Eggert <address@hidden>

    Port --enable-gcc-warnings to GCC 7
    
    Do not merge to master.
    * configure.ac: Pacify GCC 7 with -Wno-bool-operation
    -Wno-implicit-fallthrough.
    * src/search.c (boyer_moore):
    Tell GCC that CHAR_BASE, if nonzero, must be a non-ASCII character.
    * src/xterm.c (x_draw_glyphless_glyph_string_foreground):
    Tell GCC that glyph->u.glyphless.ch must be a character.
---
 configure.ac | 2 ++
 src/search.c | 1 +
 src/xterm.c  | 1 +
 3 files changed, 4 insertions(+)

diff --git a/configure.ac b/configure.ac
index 4beda65..2ccfca4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -953,6 +953,8 @@ AS_IF([test "$gl_gcc_warnings" != yes],
     gl_WARN_ADD([$w])
   done
   gl_WARN_ADD([-Wredundant-decls])     # Prefer this, as we don't use Bison.
+  gl_WARN_ADD([-Wno-bool-operation])   # Emacs 26 is clean, 25 is not.
+  gl_WARN_ADD([-Wno-implicit-fallthrough]) # Emacs 26 is clean, 25 is not.
   gl_WARN_ADD([-Wno-missing-field-initializers]) # We need this one
   gl_WARN_ADD([-Wno-sign-compare])     # Too many warnings for now
   gl_WARN_ADD([-Wno-type-limits])      # Too many warnings for now
diff --git a/src/search.c b/src/search.c
index 0793f9a..e676aac 100644
--- a/src/search.c
+++ b/src/search.c
@@ -1833,6 +1833,7 @@ boyer_moore (EMACS_INT n, unsigned char *base_pat,
     {
       /* Setup translate_prev_byte1/2/3/4 from CHAR_BASE.  Only a
         byte following them are the target of translation.  */
+      eassume (0x80 <= char_base && char_base <= MAX_CHAR);
       unsigned char str[MAX_MULTIBYTE_LENGTH];
       int cblen = CHAR_STRING (char_base, str);
 
diff --git a/src/xterm.c b/src/xterm.c
index 74e1a5a..988e98d 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -1911,6 +1911,7 @@ x_draw_glyphless_glyph_string_foreground (struct 
glyph_string *s)
        }
       else if (glyph->u.glyphless.method == GLYPHLESS_DISPLAY_HEX_CODE)
        {
+         eassume (glyph->u.glyphless.ch <= MAX_CHAR);
          sprintf (buf, "%0*X",
                   glyph->u.glyphless.ch < 0x10000 ? 4 : 6,
                   glyph->u.glyphless.ch + 0u);