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c-parse.in (structsp): Pedwarn when "enum foo" refers to an incomplete type.

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* c-parse.in (structsp): Pedwarn when "enum foo" refers to an
	incomplete type.
	(typename): Call pending_xref_error after parsing typed_typespecs.
	* c-decl.c (lookup_tag): Give error immediately rather than
	leaving it pending if the tag of the wrong type is in the same
	binding level.
	(xref_tag): Don't pedwarn for forward declarations of enum types
	here.
	* gcc.texi (Actual Bugs): Remove entry for misuse of struct, union
	and enum tags.

testsuite:
	* gcc.dg/c99-tag-1.c: New test.

From-SVN: r39372
This commit is contained in:
Joseph Myers 2001-01-31 10:24:40 +00:00 • committed by Joseph Myers
parent 92fa350add
commit 0aca1a4fd3
6 changed files with 175 additions and 12 deletions
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13
gcc/ChangeLog
View file

@ -1,3 +1,16 @@
2001-01-31 Joseph S. Myers <jsm28@cam.ac.uk>
* c-parse.in (structsp): Pedwarn when "enum foo" refers to an
incomplete type.
(typename): Call pending_xref_error after parsing typed_typespecs.
* c-decl.c (lookup_tag): Give error immediately rather than
leaving it pending if the tag of the wrong type is in the same
binding level.
(xref_tag): Don't pedwarn for forward declarations of enum types
here.
* gcc.texi (Actual Bugs): Remove entry for misuse of struct, union
and enum tags.
2001-01-31 Alexandre Oliva <aoliva@redhat.com>
* config/float-sparc.h (LDBL_MAX) [sparc32]: Fix typo.

18
gcc/c-decl.c
View file

@ -2815,6 +2815,7 @@ lookup_tag (code, name, binding_level, thislevel_only)
int thislevel_only;
{
register struct binding_level *level;
int thislevel = 1;
for (level = binding_level; level; level = level->level_chain)
{
@ -2829,12 +2830,22 @@ lookup_tag (code, name, binding_level, thislevel_only)
pending_invalid_xref = name;
pending_invalid_xref_file = input_filename;
pending_invalid_xref_line = lineno;
/* If in the same binding level as a declaration as a tag
of a different type, this must not be allowed to
shadow that tag, so give the error immediately.
(For example, "struct foo; union foo;" is invalid.) */
if (thislevel)
pending_xref_error ();
}
return TREE_VALUE (tail);
}
}
if (thislevel_only && ! level->tag_transparent)
return NULL_TREE;
if (! level->tag_transparent)
{
if (thislevel_only)
return NULL_TREE;
thislevel = 0;
}
}
return NULL_TREE;
}
@ -5112,9 +5123,6 @@ xref_tag (code, name)
ref = make_node (code);
if (code == ENUMERAL_TYPE)
{
/* (In ANSI, Enums can be referred to only if already defined.) */
if (pedantic)
pedwarn ("ISO C forbids forward references to `enum' types");
/* Give the type a default layout like unsigned int
to avoid crashing if it does not get defined. */
TYPE_MODE (ref) = TYPE_MODE (unsigned_type_node);

12
gcc/c-parse.in
View file

@ -1397,7 +1397,11 @@ structsp:
{ $$ = finish_enum ($<ttype>3, nreverse ($4),
chainon ($1, $7)); }
| enum_head identifier
{ $$ = xref_tag (ENUMERAL_TYPE, $2); }
{ $$ = xref_tag (ENUMERAL_TYPE, $2);
/* In ISO C, enumerated types can be referred to
only if already defined. */
if (pedantic && !COMPLETE_TYPE_P ($$))
pedwarn ("ISO C forbids forward references to `enum' types"); }
;
maybecomma:
@ -1534,8 +1538,10 @@ enumerator:
;
typename:
typed_typespecs absdcl
{ $$ = build_tree_list ($1, $2); }
typed_typespecs
{ pending_xref_error (); }
absdcl
{ $$ = build_tree_list ($1, $3); }
| nonempty_type_quals absdcl
{ $$ = build_tree_list ($1, $2); }
;

4
gcc/gcc.texi
View file

@ -536,10 +536,6 @@ The @code{fixproto} script will sometimes add prototypes for the
edit the offending file and place the typedef in front of the
prototypes.
@item
There are several obscure case of mis-using struct, union, and
enum tags that are not detected as errors by the compiler.
@item
When @samp{-pedantic-errors} is specified, GCC will incorrectly give
an error message when a function name is specified in an expression

4
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,7 @@
2001-01-31 Joseph S. Myers <jsm28@cam.ac.uk>
* gcc.dg/c99-tag-1.c: New test.
2001-01-31 Neil Booth <neil@daikokuya.demon.co.uk>
* gcc.dg/cpp/tr-warn1.c: Add tests.

136
gcc/testsuite/gcc.dg/c99-tag-1.c Normal file
View file

@ -0,0 +1,136 @@
/* Test for handling of tags (6.7.2.3). */
/* Origin: Joseph Myers <jsm28@cam.ac.uk> */
/* { dg-do compile } */
/* { dg-options "-std=iso9899:1999 -pedantic-errors" } */
void
foo (void)
{
/* Forward declarations of structs and unions are OK; those of enums are
not. */
{
struct s0;
struct s1 *x0;
union u0;
union u1 *x1;
enum e0; /* { dg-bogus "warning" "warning in place of error" } */
/* { dg-error "forward" "enum forward 1" { target *-*-* } 16 } */
enum e1 *x2; /* { dg-bogus "warning" "warning in place of error" } */
/* { dg-error "forward" "enum forward 2" { target *-*-* } 18 } */
/* GCC used to fail to diagnose a use of an enum inside its definition. */
enum e2 { E2A = sizeof (enum e2 *) }; /* { dg-bogus "warning" "warning in place of error" } */
/* { dg-error "forward" "enum forward 3" { target *-*-* } 21 } */
}
/* A specific type shall have its content defined at most once. But we
may redeclare the tag in different scopes. */
{
struct s0 { int i; };
{
struct s0 { long l; };
}
{
union s0 { long l; };
}
struct s0 { int i; }; /* { dg-bogus "warning" "warning in place of error" } */
/* { dg-error "rede" "struct redef" { target *-*-* } 34 } */
union u0 { int i; };
{
union u0 { long l; };
}
{
struct u0 { long l; };
}
union u0 { int i; }; /* { dg-bogus "warning" "warning in place of error" } */
/* { dg-error "rede" "union redef" { target *-*-* } 43 } */
enum e0 { E0A };
{
enum e0 { E0B };
}
{
struct e0 { long l; };
}
enum e0 { E0B }; /* { dg-bogus "warning" "warning in place of error" } */
/* { dg-error "rede" "enum redef" { target *-*-* } 52 } */
}
/* Structure, union and enumerated types have a single namespace of tags. */
{
struct s0;
struct s1;
struct s2 { int i; };
struct s2;
struct s3 { int i; };
struct s2 sv;
union u0;
union u2 { int i; };
union u2;
union u2 uv;
enum e0 { E0A };
enum e1 { E1A };
/* None of the following are allowed; some were not detected by GCC. */
union s0; /* { dg-bogus "warning" "warning in place of error" } */
/* { dg-error "wrong" "wrong tag type" { target *-*-* } 70 } */
union s1 { int i; }; /* { dg-bogus "warning" "warning in place of error" } */
/* { dg-error "wrong" "wrong tag type" { target *-*-* } 72 } */
union s2; /* { dg-bogus "warning" "warning in place of error" } */
/* { dg-error "wrong" "wrong tag type" { target *-*-* } 74 } */
union s3 { int i; }; /* { dg-bogus "warning" "warning in place of error" } */
/* { dg-error "wrong" "wrong tag type" { target *-*-* } 76 } */
enum u0 { U0A }; /* { dg-bogus "warning" "warning in place of error" } */
/* { dg-error "wrong" "wrong tag type" { target *-*-* } 78 } */
enum u2 { U2A }; /* { dg-bogus "warning" "warning in place of error" } */
/* { dg-error "wrong" "wrong tag type" { target *-*-* } 80 } */
struct e0; /* { dg-bogus "warning" "warning in place of error" } */
/* { dg-error "wrong" "wrong tag type" { target *-*-* } 82 } */
struct e1 { int i; }; /* { dg-bogus "warning" "warning in place of error" } */
/* { dg-error "wrong" "wrong tag type" { target *-*-* } 84 } */
}
/* Explicit shadowing in inner scopes is OK, but references to the tag
that don't explicitly shadow it must (whether in declarations or
expressions) use the correct one of struct/union/enum. */
{
struct s0;
struct s1;
struct s2 { int i; };
struct s2;
struct s3 { int i; };
struct s2 sv;
union u0;
union u2 { int i; };
union u2;
union u2 uv;
enum e0 { E0A };
enum e1 { E1A };
{
union s0;
union s1;
union s2;
union s3;
struct u0;
struct u2;
struct e0;
union e1;
}
{
union s0 *x0; /* { dg-bogus "warning" "warning in place of error" } */
/* { dg-error "wrong" "wrong tag type" { target *-*-* } 114 } */
int x1[sizeof (union s1 *)]; /* { dg-bogus "warning" "warning in place of error" } */
/* { dg-error "wrong" "wrong tag type" { target *-*-* } 116 } */
struct t;
union s2 *x2;
/* { dg-error "wrong" "wrong tag type" { target *-*-* } 119 } */
int x3[sizeof (union s3 *)]; /* { dg-bogus "warning" "warning in place of error" } */
/* { dg-error "wrong" "wrong tag type" { target *-*-* } 121 } */
struct u;
enum u0 *y0; /* { dg-bogus "warning" "warning in place of error" } */
/* { dg-error "wrong|forward" "wrong tag type" { target *-*-* } 124 } */
int y1[sizeof (enum u2 *)]; /* { dg-bogus "warning" "warning in place of error" } */
/* { dg-error "wrong" "wrong tag type" { target *-*-* } 126 } */
struct v;
struct e0 *z0; /* { dg-bogus "warning" "warning in place of error" } */
/* { dg-error "wrong" "wrong tag type" { target *-*-* } 129 } */
int z1[sizeof (struct e1 *)]; /* { dg-bogus "warning" "warning in place of error" } */
/* { dg-error "wrong" "wrong tag type" { target *-*-* } 131 } */
struct w;
}
}
}