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re PR c/4784 (Anonymous structs issues) 

PR c/4784
	* c-decl.c (detect_field_duplicates_hash): New.  Handle anonymous
	structures and unions recursively.
	(detect_field_duplicates): Move duplicate detection with a hash to
	detect_field_duplicates_hash.  Always use a hash if anonymous
	structures or unions are present.
	* doc/extend.texi (Unnamed Fields): Document that duplicate fields
	give errors.

testsuite:
	* gcc.dg/anon-struct-9.c: New test.

From-SVN: r159204
This commit is contained in:
Joseph Myers 2010-05-09 17:19:28 +01:00 committed by Joseph Myers
parent 44f276c65f
commit 492fc0eec5
5 changed files with 179 additions and 17 deletions
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11
gcc/ChangeLog
View File

@ -1,3 +1,14 @@
2010-05-09 Joseph Myers <joseph@codesourcery.com>
PR c/4784
* c-decl.c (detect_field_duplicates_hash): New. Handle anonymous
structures and unions recursively.
(detect_field_duplicates): Move duplicate detection with a hash to
detect_field_duplicates_hash. Always use a hash if anonymous
structures or unions are present.
* doc/extend.texi (Unnamed Fields): Document that duplicate fields
give errors.
2010-05-09 H.J. Lu <hongjiu.lu@intel.com>
PR target/44046

48
gcc/c-decl.c
View File

@ -6629,6 +6629,31 @@ grokfield (location_t loc,
return value;
}
/* Subroutine of detect_field_duplicates: add the fields of FIELDLIST
to HTAB, giving errors for any duplicates. */
static void
detect_field_duplicates_hash (tree fieldlist, htab_t htab)
{
tree x, y;
void **slot;
for (x = fieldlist; x ; x = TREE_CHAIN (x))
if ((y = DECL_NAME (x)) != 0)
{
slot = htab_find_slot (htab, y, INSERT);
if (*slot)
{
error ("duplicate member %q+D", x);
DECL_NAME (x) = NULL_TREE;
}
*slot = y;
}
else if (TREE_CODE (TREE_TYPE (x)) == RECORD_TYPE
|| TREE_CODE (TREE_TYPE (x)) == UNION_TYPE)
detect_field_duplicates_hash (TYPE_FIELDS (TREE_TYPE (x)), htab);
}
/* Generate an error for any duplicate field names in FIELDLIST. Munge
the list such that this does not present a problem later. */
@ -6647,11 +6672,16 @@ detect_field_duplicates (tree fieldlist)
return;
do {
timeout--;
if (DECL_NAME (x) == NULL_TREE
&& (TREE_CODE (TREE_TYPE (x)) == RECORD_TYPE
|| TREE_CODE (TREE_TYPE (x)) == UNION_TYPE))
timeout = 0;
x = TREE_CHAIN (x);
} while (timeout > 0 && x);
/* If there were "few" fields, avoid the overhead of allocating
a hash table. Instead just do the nested traversal thing. */
/* If there were "few" fields and no anonymous structures or unions,
avoid the overhead of allocating a hash table. Instead just do
the nested traversal thing. */
if (timeout > 0)
{
for (x = TREE_CHAIN (fieldlist); x ; x = TREE_CHAIN (x))
@ -6668,20 +6698,8 @@ detect_field_duplicates (tree fieldlist)
else
{
htab_t htab = htab_create (37, htab_hash_pointer, htab_eq_pointer, NULL);
void **slot;
for (x = fieldlist; x ; x = TREE_CHAIN (x))
if ((y = DECL_NAME (x)) != 0)
{
slot = htab_find_slot (htab, y, INSERT);
if (*slot)
{
error ("duplicate member %q+D", x);
DECL_NAME (x) = NULL_TREE;
}
*slot = y;
}
detect_field_duplicates_hash (fieldlist, htab);
htab_delete (htab);
}
}

3
gcc/doc/extend.texi
View File

@ -12760,8 +12760,7 @@ struct @{
@end smallexample
It is ambiguous which @code{a} is being referred to with @samp{foo.a}.
Such constructs are not supported and must be avoided. In the future,
such constructs may be detected and treated as compilation errors.
The compiler gives errors for such constructs.
@opindex fms-extensions
Unless @option{-fms-extensions} is used, the unnamed field must be a

5
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,8 @@
2010-05-09 Joseph Myers <joseph@codesourcery.com>
PR c/4784
* gcc.dg/anon-struct-9.c: New test.
2010-05-09 Richard Guenther <rguenther@suse.de>
PR middle-end/44043

129
gcc/testsuite/gcc.dg/anon-struct-9.c Normal file
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@ -0,0 +1,129 @@
/* Test for diagnostics for duplicate member names in anonymous
structures and unions. PR 4784. */
/* { dg-do compile } */
/* { dg-options "" } */
struct s1
{
int x;
struct
{
int x; /* { dg-error "duplicate member" } */
};
};
struct s2
{
struct
{
int a;
struct
{
int b;
};
};
struct
{
int b; /* { dg-error "duplicate member" } */
};
};
struct s3
{
struct
{
int a;
struct
{
int b;
};
};
struct
{
int b; /* { dg-error "duplicate member" } */
int c;
};
};
struct s4
{
int x;
struct
{
int x;
} y;
};
union u1
{
int x;
union
{
int x; /* { dg-error "duplicate member" } */
};
};
union u2
{
union
{
int a;
union
{
int b;
};
};
union
{
int b; /* { dg-error "duplicate member" } */
};
};
union u3
{
union
{
int a;
union
{
int b;
};
};
union
{
int b; /* { dg-error "duplicate member" } */
int c;
};
};
union u4
{
int x;
union
{
int x;
} y;
};
#define D10(x) int x##0; int x##1; int x##2; int x##3; int x##4; int x##5; int x##6; int x##7; int x##8; int x##9;
#define D100(x) D10(x##0) D10(x##1) D10(x##2) D10(x##3) D10(x##4) D10(x##5) D10(x##6) D10(x##7) D10(x##8) D10(x##9)
#define S10(x) struct { D100(x##0) }; struct { D100(x##1) }; struct { D100(x##2) }; struct { D100(x##3) }; struct { D100(x##4) }; struct { D100(x##5) }; struct { D100(x##6) }; struct { D100(x##7) }; struct { D100(x##8) }; struct { D100(x##9) };
struct sbig
{
S10(a)
S10(b)
S10(c)
S10(d)
S10(e)
S10(f)
S10(g)
S10(h)
S10(i)
S10(j)
struct
{
int a123; /* { dg-error "duplicate member" } */
};
};