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* [Bug c/30006] New: Compound literal in structure initializer causes irrelevant warning
@ 2006-11-28 8:47 yar at bsd dot chem dot msu dot ru
2006-12-02 8:10 ` [Bug c/30006] Compound literal in structure initializer causes missing initializer warning to happen pinskia at gcc dot gnu dot org
2008-06-06 9:51 ` he at uninett dot no
0 siblings, 2 replies; 3+ messages in thread
From: yar at bsd dot chem dot msu dot ru @ 2006-11-28 8:47 UTC (permalink / raw)
To: gcc-bugs
Note: This report doesn't use the FreeBSD system GCC compiler; it uses an
original GCC 4.3.0 snapshot built and installed separately. However, the bug
also persists in GCC 3.4.6 found in FreeBSD, and in original GCC 4.2.0.
The complete test.c program:
struct foo {
char *p;
int i;
} bar = {
#ifdef BUG
.p = (char[]){"abc"}
#else
.p = "abc"
#endif
};
I.e., it will use a plain string to initialize bar.p if BUG is undefined,
but it will use a compound literal if BUG is defined.
The attempts to compile it (blank lines added for clarity):
$gcc43 -v
Using built-in specs.
Target: i386-portbld-freebsd7.0
Configured with: ./..//gcc-4.3-20061125/configure --disable-nls
--with-system-zlib --with-libiconv-prefix=/usr/local --with-gmp=/usr/local
--program-suffix=43 --libdir=/usr/local/lib/gcc-4.3.0
--with-gxx-include-dir=/usr/local/lib/gcc-4.3.0/include/c++/
--infodir=/usr/local/info/gcc43 --disable-rpath --prefix=/usr/local
i386-portbld-freebsd7.0
Thread model: posix
gcc version 4.3.0 20061125 (experimental)
$gcc43 -Wall -W -Werror -c test.c
$gcc43 -DBUG -Wall -W -Werror -c test.c
cc1: warnings being treated as errors
test.c:10: warning: missing initializer
test.c:10: warning: (near initialization for 'bar.i')
That is, using a compound literal instead of a plain string
to initialize bar.p leads to a warning on a different structure
member, bar.i.
AFAIK GCC would issue such a warning if an old-style structure
initializer were used and not all its members were specified.
However, the example program uses a C99 structure initializer,
and GCC is happy about it unless the compound literal is there
(see the successful compilation when BUG wasn't defined.)
Although it's just a warning, it can be painful for projects
that enforce -Werror policy for their code.
Thanks a lot!
--
Summary: Compound literal in structure initializer causes
irrelevant warning
Product: gcc
Version: 4.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: yar at bsd dot chem dot msu dot ru
GCC build triplet: i386-portbld-freebsd7.0
GCC host triplet: i386-portbld-freebsd7.0
GCC target triplet: i386-portbld-freebsd7.0
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30006
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c/30006] Compound literal in structure initializer causes missing initializer warning to happen
2006-11-28 8:47 [Bug c/30006] New: Compound literal in structure initializer causes irrelevant warning yar at bsd dot chem dot msu dot ru
@ 2006-12-02 8:10 ` pinskia at gcc dot gnu dot org
2008-06-06 9:51 ` he at uninett dot no
1 sibling, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2006-12-02 8:10 UTC (permalink / raw)
To: gcc-bugs
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------- Comment #1 from pinskia at gcc dot gnu dot org 2006-12-02 08:10 -------
Confirmed.
/* Do not warn if this level of the initializer uses member
designators; it is likely to be deliberate. */
if (constructor_unfilled_fields && !constructor_designated)
I think we forget to push/pop the context for compound literals.
Here is another testcase where we warn:
struct foo {
char *p;
int i;
int j;
} bar = {
.j = 1,
.p = (char[]){"abc"}
};
And one where we don't as the order of the compound literal has changed:
struct foo {
char *p;
int i;
int j;
} bar = {
.p = (char[]){"abc"},
.j = 1
};
-----
Here is an even more complex testcase where we warn too much:
struct h
{
int x, y;
};
struct g
{
struct h *i;
int j;
};
struct foo {
struct g *v;
int i1;
int j1;
} bar = {
&(struct g) {
.i = &(struct h){1}
}
};
------------------------------------
t.c:16: warning: missing initializer
t.c:16: warning: (near initialization for (anonymous).y)
t.c:17: warning: missing initializer
t.c:17: warning: (near initialization for (anonymous).j)
t.c:18: warning: missing initializer
t.c:18: warning: (near initialization for bar.i1)
We should not warn about (anonymous).j.
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever Confirmed|0 |1
GCC build triplet|i386-portbld-freebsd7.0 |
GCC host triplet|i386-portbld-freebsd7.0 |
GCC target triplet|i386-portbld-freebsd7.0 |
Keywords| |diagnostic
Known to fail| |2.95 3.2.3 3.4.0 4.0.0 4.2.0
| |4.0.4 4.1.2 4.2.0 4.3.0
Last reconfirmed|0000-00-00 00:00:00 |2006-12-02 08:10:07
date| |
Summary|Compound literal in |Compound literal in
|structure initializer causes|structure initializer causes
|irrelevant warning |missing initializer warning
| |to happen
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30006
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c/30006] Compound literal in structure initializer causes missing initializer warning to happen
2006-11-28 8:47 [Bug c/30006] New: Compound literal in structure initializer causes irrelevant warning yar at bsd dot chem dot msu dot ru
2006-12-02 8:10 ` [Bug c/30006] Compound literal in structure initializer causes missing initializer warning to happen pinskia at gcc dot gnu dot org
@ 2008-06-06 9:51 ` he at uninett dot no
1 sibling, 0 replies; 3+ messages in thread
From: he at uninett dot no @ 2008-06-06 9:51 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from he at uninett dot no 2008-06-06 09:50 -------
Hi,
here is another testcase which I think might have the
same or at least a similar root cause:
struct o {
struct n {
int b;
int a;
} n;
};
const struct o o = {
#ifdef BUG
.n.b = 1
#else
.n = { .b = 1 }
#endif
};
When compiled with "-c -Wextra" with gcc 4.1.3 as found in NetBSD-current,
this will complain about missing initializers if BUG is defined, even though
a C99-style initializer is used, something which I thought should have obviated
the insistence on initializing all the fields of the struct.
--
he at uninett dot no changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |he at uninett dot no
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30006
^ permalink raw reply [flat|nested] 3+ messages in thread
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2006-11-28 8:47 [Bug c/30006] New: Compound literal in structure initializer causes irrelevant warning yar at bsd dot chem dot msu dot ru
2006-12-02 8:10 ` [Bug c/30006] Compound literal in structure initializer causes missing initializer warning to happen pinskia at gcc dot gnu dot org
2008-06-06 9:51 ` he at uninett dot no
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