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maint: Fix macros with broken 'do/while(0); ' usage

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The point of writing a macro embedded in a 'do { ... } while (0)'
loop (particularly if the macro has multiple statements or would
otherwise end with an 'if' statement) is so that the macro can be
used as a drop-in statement with the caller supplying the
trailing ';'.  Although our coding style frowns on brace-less 'if':
  if (cond)
    statement;
  else
    something else;
that is the classic case where failure to use do/while(0) wrapping
would cause the 'else' to pair with any embedded 'if' in the macro
rather than the intended outer 'if'.  But conversely, if the macro
includes an embedded ';', then the same brace-less coding style
would now have two statements, making the 'else' a syntax error
rather than pairing with the outer 'if'.  Thus, even though our
coding style with required braces is not impacted, ending a macro
with ';' makes our code harder to port to projects that use
brace-less styles.

The change should have no semantic impact.  I was not able to
fully compile-test all of the changes (as some of them are
examples of the ugly bit-rotting debug print statements that are
completely elided by default, and I didn't want to recompile
with the necessary -D witnesses - cleaning those up is left as a
bite-sized task for another day); I did, however, audit that for
all files touched, all callers of the changed macros DID supply
a trailing ';' at the callsite, and did not appear to be used
as part of a brace-less conditional.

Found mechanically via: $ git grep -B1 'while (0);' | grep -A1 \\\\

Signed-off-by: Eric Blake <eblake@redhat.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20171201232433.25193-7-eblake@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Eric Blake 2017-12-01 17:24:32 -06:00 • committed by Paolo Bonzini
parent 241187c118
commit 2562755ee7
34 changed files with 42 additions and 42 deletions
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8
ui/sdl_zoom_template.h
View file

@ -34,22 +34,22 @@
#define setRed(r, pcolor) do { \
*pcolor = ((*pcolor) & (~(dpf->Rmask))) + \
(((r) & (dpf->Rmask >> dpf->Rshift)) << dpf->Rshift); \
} while (0);
} while (0)
#define setGreen(g, pcolor) do { \
*pcolor = ((*pcolor) & (~(dpf->Gmask))) + \
(((g) & (dpf->Gmask >> dpf->Gshift)) << dpf->Gshift); \
} while (0);
} while (0)
#define setBlue(b, pcolor) do { \
*pcolor = ((*pcolor) & (~(dpf->Bmask))) + \
(((b) & (dpf->Bmask >> dpf->Bshift)) << dpf->Bshift); \
} while (0);
} while (0)
#define setAlpha(a, pcolor) do { \
*pcolor = ((*pcolor) & (~(dpf->Amask))) + \
(((a) & (dpf->Amask >> dpf->Ashift)) << dpf->Ashift); \
} while (0);
} while (0)
static void glue(sdl_zoom_rgb, BPP)(SDL_Surface *src, SDL_Surface *dst, int smooth,
SDL_Rect *dst_rect)