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C1x typedef redeclarations patch
- From: "Joseph S. Myers" <joseph at codesourcery dot com>
- To: gcc-patches at gcc dot gnu dot org
- Date: Sun, 23 May 2010 20:49:19 +0000 (UTC)
- Subject: C1x typedef redeclarations patch
This patch implements C1X rules on duplicate typedef declarations.
This is something previously allowed by GCC in system headers that C1X
allows more generally but with a restriction that the types be the
same (not just compatible) - which in turn requires a warning in the
case of VLAs that there might be a constraint violation that cannot be
detected at compile time.
Bootstrapped with no regressions on x86_64-unknown-linux-gnu. Applied
to mainline.
2010-05-23 Joseph Myers <joseph@codesourcery.com>
* c-decl.c (diagnose_mismatched_decls): Give error for duplicate
typedefs with different but compatible types. Allow duplicate
typedefs with the same type except for pedantic non-C1X, but give
warning for variably modified types.
* c-typeck.c (tagged_types_tu_compatible_p,
function_types_compatible_p, type_lists_compatible_p,
comptypes_internal): Add parameter different_types_p; set
*different_types_p for different but compatible types. All
callers changed.
(comptypes_check_different_types): New.
* c-tree.h (comptypes_check_different_types): Declare.
testsuite:
2010-05-23 Joseph Myers <joseph@codesourcery.com>
* gcc.dg/c1x-typedef-1.c, gcc.dg/c1x-typedef-2.c,
gcc.dg/c90-typedef-1.c, gcc.dg/c99-typedef-1.c: New tests.
* gcc.dg/decl-8.c: Use -std=gnu89 -pedantic-errors.
Index: testsuite/gcc.dg/c1x-typedef-1.c
===================================================================
--- testsuite/gcc.dg/c1x-typedef-1.c (revision 0)
+++ testsuite/gcc.dg/c1x-typedef-1.c (revision 0)
@@ -0,0 +1,68 @@
+/* Test typedef redeclaration in C1X. */
+/* { dg-do compile } */
+/* { dg-options "-std=c1x -pedantic-errors" } */
+
+/* C1X permits typedefs to be redeclared to the same type, but not to
+ different-but-compatible types. */
+
+#include <limits.h>
+
+typedef int TI;
+typedef int TI2;
+typedef TI2 TI;
+typedef TI TI2;
+
+enum e { E1 = 0, E2 = INT_MAX, E3 = -1 };
+typedef enum e TE;
+typedef enum e TE; /* { dg-message "previous declaration" } */
+typedef int TE; /* { dg-error "with different type" } */
+
+struct s;
+typedef struct s TS;
+struct s { int i; };
+typedef struct s TS;
+
+typedef int IA[];
+typedef TI2 IA[]; /* { dg-message "previous declaration" } */
+typedef int A2[2];
+typedef TI A2[2]; /* { dg-message "previous declaration" } */
+typedef IA A2; /* { dg-error "with different type" } */
+typedef int A3[3];
+typedef A3 IA; /* { dg-error "with different type" } */
+
+typedef void F(int);
+typedef void F(TI); /* { dg-message "previous declaration" } */
+typedef void F(enum e); /* { dg-error "with different type" } */
+
+typedef int G(void);
+typedef TI G(void); /* { dg-message "previous declaration" } */
+typedef enum e G(void); /* { dg-error "with different type" } */
+
+typedef int *P;
+typedef TI *P; /* { dg-message "previous declaration" } */
+typedef enum e *P; /* { dg-error "with different type" } */
+
+typedef void F2();
+typedef void F2(); /* { dg-message "previous declaration" } */
+typedef void F2(int); /* { dg-error "with different type" } */
+
+void
+f (void)
+{
+ int a = 1;
+ int b = 2;
+ typedef void FN(int (*p)[a]);
+ typedef void FN(int (*p)[b]);
+ typedef void FN(int (*p)[*]); /* { dg-message "previous declaration" } */
+ typedef void FN(int (*p)[1]); /* { dg-error "with different type" } */
+ typedef void FN2(int (*p)[a]);
+ typedef void FN2(int (*p)[b]);
+ typedef void FN2(int (*p)[*]); /* { dg-message "previous declaration" } */
+ typedef void FN2(int (*p)[]); /* { dg-error "with different type" } */
+ typedef int AV[a]; /* { dg-message "previous declaration" } */
+ typedef int AV[b-1]; /* { dg-warning "may be a constraint violation at runtime" } */
+ typedef int AAa[a];
+ typedef int AAb[b-1];
+ typedef AAa *VF(void); /* { dg-message "previous declaration" } */
+ typedef AAb *VF(void); /* { dg-warning "may be a constraint violation at runtime" } */
+}
Index: testsuite/gcc.dg/c90-typedef-1.c
===================================================================
--- testsuite/gcc.dg/c90-typedef-1.c (revision 0)
+++ testsuite/gcc.dg/c90-typedef-1.c (revision 0)
@@ -0,0 +1,6 @@
+/* Test typedef redeclaration not permitted in C90. */
+/* { dg-do compile } */
+/* { dg-options "-std=iso9899:1990 -pedantic-errors" } */
+
+typedef int TI; /* { dg-message "previous declaration" } */
+typedef int TI; /* { dg-error "redefinition of typedef" } */
Index: testsuite/gcc.dg/c1x-typedef-2.c
===================================================================
--- testsuite/gcc.dg/c1x-typedef-2.c (revision 0)
+++ testsuite/gcc.dg/c1x-typedef-2.c (revision 0)
@@ -0,0 +1,18 @@
+/* Test typedef redeclaration in C1X. Side effects from duplicate
+ declarations still apply. */
+/* { dg-do run } */
+/* { dg-options "-std=c1x -pedantic-errors" } */
+
+extern void exit (int);
+extern void abort (void);
+
+int
+main (void)
+{
+ int a = 1, b = 1;
+ typedef int T[++a]; /* { dg-message "previous declaration" } */
+ typedef int T[++b]; /* { dg-warning "may be a constraint violation at runtime" } */
+ if (a != 2 || b != 2)
+ abort ();
+ exit (0);
+}
Index: testsuite/gcc.dg/decl-8.c
===================================================================
--- testsuite/gcc.dg/decl-8.c (revision 159753)
+++ testsuite/gcc.dg/decl-8.c (working copy)
@@ -1,7 +1,7 @@
/* Test diagnostics for duplicate typedefs. Basic diagnostics. */
/* Origin: Joseph Myers <joseph@codesourcery.com> */
/* { dg-do compile } */
-/* { dg-options "" } */
+/* { dg-options "-std=gnu89 -pedantic-errors" } */
typedef int I; /* { dg-message "note: previous declaration of 'I' was here" } */
typedef int I; /* { dg-error "redefinition of typedef 'I'" } */
Index: testsuite/gcc.dg/c99-typedef-1.c
===================================================================
--- testsuite/gcc.dg/c99-typedef-1.c (revision 0)
+++ testsuite/gcc.dg/c99-typedef-1.c (revision 0)
@@ -0,0 +1,6 @@
+/* Test typedef redeclaration not permitted in C99. */
+/* { dg-do compile } */
+/* { dg-options "-std=iso9899:1999 -pedantic-errors" } */
+
+typedef int TI; /* { dg-message "previous declaration" } */
+typedef int TI; /* { dg-error "redefinition of typedef" } */
Index: c-tree.h
===================================================================
--- c-tree.h (revision 159753)
+++ c-tree.h (working copy)
@@ -506,6 +506,7 @@ extern tree c_objc_common_truthvalue_con
extern tree require_complete_type (tree);
extern int same_translation_unit_p (const_tree, const_tree);
extern int comptypes (tree, tree);
+extern int comptypes_check_different_types (tree, tree, bool *);
extern bool c_vla_type_p (const_tree);
extern bool c_mark_addressable (tree);
extern void c_incomplete_type_error (const_tree, const_tree);
Index: c-decl.c
===================================================================
--- c-decl.c (revision 159753)
+++ c-decl.c (working copy)
@@ -1786,18 +1786,48 @@ diagnose_mismatched_decls (tree newdecl,
/* Redeclaration of a type is a constraint violation (6.7.2.3p1),
but silently ignore the redeclaration if either is in a system
- header. (Conflicting redeclarations were handled above.) */
+ header. (Conflicting redeclarations were handled above.) This
+ is allowed for C1X if the types are the same, not just
+ compatible. */
if (TREE_CODE (newdecl) == TYPE_DECL)
{
+ bool types_different = false;
+ int comptypes_result;
+
+ comptypes_result
+ = comptypes_check_different_types (oldtype, newtype, &types_different);
+
+ if (comptypes_result != 1 || types_different)
+ {
+ error ("redefinition of typedef %q+D with different type", newdecl);
+ locate_old_decl (olddecl);
+ return false;
+ }
+
if (DECL_IN_SYSTEM_HEADER (newdecl)
|| DECL_IN_SYSTEM_HEADER (olddecl)
|| TREE_NO_WARNING (newdecl)
|| TREE_NO_WARNING (olddecl))
return true; /* Allow OLDDECL to continue in use. */
- error ("redefinition of typedef %q+D", newdecl);
- locate_old_decl (olddecl);
- return false;
+ if (pedantic && !flag_isoc1x)
+ {
+ pedwarn (input_location, OPT_pedantic,
+ "redefinition of typedef %q+D", newdecl);
+ locate_old_decl (olddecl);
+ }
+ else if (variably_modified_type_p (newtype, NULL))
+ {
+ /* Whether there is a constraint violation for the types not
+ being the same cannot be determined at compile time; a
+ warning that there may be one at runtime is considered
+ appropriate (WG14 reflector message 11743, 8 May 2009). */
+ warning (0, "redefinition of typedef %q+D may be a constraint "
+ "violation at runtime", newdecl);
+ locate_old_decl (olddecl);
+ }
+
+ return true;
}
/* Function declarations can either be 'static' or 'extern' (no
Index: c-typeck.c
===================================================================
--- c-typeck.c (revision 159753)
+++ c-typeck.c (working copy)
@@ -76,10 +76,12 @@ static int require_constant_elements;
static bool null_pointer_constant_p (const_tree);
static tree qualify_type (tree, tree);
-static int tagged_types_tu_compatible_p (const_tree, const_tree, bool *);
+static int tagged_types_tu_compatible_p (const_tree, const_tree, bool *,
+ bool *);
static int comp_target_types (location_t, tree, tree);
-static int function_types_compatible_p (const_tree, const_tree, bool *);
-static int type_lists_compatible_p (const_tree, const_tree, bool *);
+static int function_types_compatible_p (const_tree, const_tree, bool *,
+ bool *);
+static int type_lists_compatible_p (const_tree, const_tree, bool *, bool *);
static tree lookup_field (tree, tree);
static int convert_arguments (tree, VEC(tree,gc) *, VEC(tree,gc) *, tree,
tree);
@@ -106,7 +108,7 @@ static void readonly_error (tree, enum l
static void readonly_warning (tree, enum lvalue_use);
static int lvalue_or_else (const_tree, enum lvalue_use);
static void record_maybe_used_decl (tree);
-static int comptypes_internal (const_tree, const_tree, bool *);
+static int comptypes_internal (const_tree, const_tree, bool *, bool *);
/* Return true if EXP is a null pointer constant, false otherwise. */
@@ -972,7 +974,7 @@ comptypes (tree type1, tree type2)
const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
int val;
- val = comptypes_internal (type1, type2, NULL);
+ val = comptypes_internal (type1, type2, NULL, NULL);
free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
return val;
@@ -987,7 +989,23 @@ comptypes_check_enum_int (tree type1, tr
const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
int val;
- val = comptypes_internal (type1, type2, enum_and_int_p);
+ val = comptypes_internal (type1, type2, enum_and_int_p, NULL);
+ free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
+
+ return val;
+}
+
+/* Like comptypes, but if it returns nonzero for different types, it
+ sets *DIFFERENT_TYPES_P to true. */
+
+int
+comptypes_check_different_types (tree type1, tree type2,
+ bool *different_types_p)
+{
+ const struct tagged_tu_seen_cache * tagged_tu_seen_base1 = tagged_tu_seen_base;
+ int val;
+
+ val = comptypes_internal (type1, type2, NULL, different_types_p);
free_all_tagged_tu_seen_up_to (tagged_tu_seen_base1);
return val;
@@ -998,11 +1016,17 @@ comptypes_check_enum_int (tree type1, tr
but a warning may be needed if you use them together. If
ENUM_AND_INT_P is not NULL, and one type is an enum and the other a
compatible integer type, then this sets *ENUM_AND_INT_P to true;
- *ENUM_AND_INT_P is never set to false. This differs from
- comptypes, in that we don't free the seen types. */
+ *ENUM_AND_INT_P is never set to false. If DIFFERENT_TYPES_P is not
+ NULL, and the types are compatible but different enough not to be
+ permitted in C1X typedef redeclarations, then this sets
+ *DIFFERENT_TYPES_P to true; *DIFFERENT_TYPES_P is never set to
+ false, but may or may not be set if the types are incompatible.
+ This differs from comptypes, in that we don't free the seen
+ types. */
static int
-comptypes_internal (const_tree type1, const_tree type2, bool *enum_and_int_p)
+comptypes_internal (const_tree type1, const_tree type2, bool *enum_and_int_p,
+ bool *different_types_p)
{
const_tree t1 = type1;
const_tree t2 = type2;
@@ -1032,14 +1056,24 @@ comptypes_internal (const_tree type1, co
if (TREE_CODE (t1) == ENUMERAL_TYPE && TREE_CODE (t2) != ENUMERAL_TYPE)
{
t1 = c_common_type_for_size (TYPE_PRECISION (t1), TYPE_UNSIGNED (t1));
- if (enum_and_int_p != NULL && TREE_CODE (t2) != VOID_TYPE)
- *enum_and_int_p = true;
+ if (TREE_CODE (t2) != VOID_TYPE)
+ {
+ if (enum_and_int_p != NULL)
+ *enum_and_int_p = true;
+ if (different_types_p != NULL)
+ *different_types_p = true;
+ }
}
else if (TREE_CODE (t2) == ENUMERAL_TYPE && TREE_CODE (t1) != ENUMERAL_TYPE)
{
t2 = c_common_type_for_size (TYPE_PRECISION (t2), TYPE_UNSIGNED (t2));
- if (enum_and_int_p != NULL && TREE_CODE (t1) != VOID_TYPE)
- *enum_and_int_p = true;
+ if (TREE_CODE (t1) != VOID_TYPE)
+ {
+ if (enum_and_int_p != NULL)
+ *enum_and_int_p = true;
+ if (different_types_p != NULL)
+ *different_types_p = true;
+ }
}
if (t1 == t2)
@@ -1079,11 +1113,12 @@ comptypes_internal (const_tree type1, co
break;
val = (TREE_TYPE (t1) == TREE_TYPE (t2)
? 1 : comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2),
- enum_and_int_p));
+ enum_and_int_p, different_types_p));
break;
case FUNCTION_TYPE:
- val = function_types_compatible_p (t1, t2, enum_and_int_p);
+ val = function_types_compatible_p (t1, t2, enum_and_int_p,
+ different_types_p);
break;
case ARRAY_TYPE:
@@ -1097,9 +1132,13 @@ comptypes_internal (const_tree type1, co
/* Target types must match incl. qualifiers. */
if (TREE_TYPE (t1) != TREE_TYPE (t2)
&& 0 == (val = comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2),
- enum_and_int_p)))
+ enum_and_int_p,
+ different_types_p)))
return 0;
+ if (different_types_p != NULL
+ && (d1 == 0) != (d2 == 0))
+ *different_types_p = true;
/* Sizes must match unless one is missing or variable. */
if (d1 == 0 || d2 == 0 || d1 == d2)
break;
@@ -1116,6 +1155,9 @@ comptypes_internal (const_tree type1, co
d1_variable = d1_variable || (d1_zero && c_vla_type_p (t1));
d2_variable = d2_variable || (d2_zero && c_vla_type_p (t2));
+ if (different_types_p != NULL
+ && d1_variable != d2_variable)
+ *different_types_p = true;
if (d1_variable || d2_variable)
break;
if (d1_zero && d2_zero)
@@ -1141,15 +1183,17 @@ comptypes_internal (const_tree type1, co
break;
if (attrval != 2)
- return tagged_types_tu_compatible_p (t1, t2, enum_and_int_p);
- val = tagged_types_tu_compatible_p (t1, t2, enum_and_int_p);
+ return tagged_types_tu_compatible_p (t1, t2, enum_and_int_p,
+ different_types_p);
+ val = tagged_types_tu_compatible_p (t1, t2, enum_and_int_p,
+ different_types_p);
}
break;
case VECTOR_TYPE:
val = (TYPE_VECTOR_SUBPARTS (t1) == TYPE_VECTOR_SUBPARTS (t2)
&& comptypes_internal (TREE_TYPE (t1), TREE_TYPE (t2),
- enum_and_int_p));
+ enum_and_int_p, different_types_p));
break;
default:
@@ -1281,11 +1325,12 @@ free_all_tagged_tu_seen_up_to (const str
compatible. If the two types are not the same (which has been
checked earlier), this can only happen when multiple translation
units are being compiled. See C99 6.2.7 paragraph 1 for the exact
- rules. ENUM_AND_INT_P is as in comptypes_internal. */
+ rules. ENUM_AND_INT_P and DIFFERENT_TYPES_P are as in
+ comptypes_internal. */
static int
tagged_types_tu_compatible_p (const_tree t1, const_tree t2,
- bool *enum_and_int_p)
+ bool *enum_and_int_p, bool *different_types_p)
{
tree s1, s2;
bool needs_warning = false;
@@ -1396,7 +1441,7 @@ tagged_types_tu_compatible_p (const_tree
if (DECL_NAME (s1) != DECL_NAME (s2))
break;
result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2),
- enum_and_int_p);
+ enum_and_int_p, different_types_p);
if (result != 1 && !DECL_NAME (s1))
break;
@@ -1432,7 +1477,8 @@ tagged_types_tu_compatible_p (const_tree
int result;
result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2),
- enum_and_int_p);
+ enum_and_int_p,
+ different_types_p);
if (result != 1 && !DECL_NAME (s1))
continue;
@@ -1475,7 +1521,7 @@ tagged_types_tu_compatible_p (const_tree
|| DECL_NAME (s1) != DECL_NAME (s2))
break;
result = comptypes_internal (TREE_TYPE (s1), TREE_TYPE (s2),
- enum_and_int_p);
+ enum_and_int_p, different_types_p);
if (result == 0)
break;
if (result == 2)
@@ -1504,11 +1550,11 @@ tagged_types_tu_compatible_p (const_tree
Otherwise, if one type specifies only the number of arguments,
the other must specify that number of self-promoting arg types.
Otherwise, the argument types must match.
- ENUM_AND_INT_P is as in comptypes_internal. */
+ ENUM_AND_INT_P and DIFFERENT_TYPES_P are as in comptypes_internal. */
static int
function_types_compatible_p (const_tree f1, const_tree f2,
- bool *enum_and_int_p)
+ bool *enum_and_int_p, bool *different_types_p)
{
tree args1, args2;
/* 1 if no need for warning yet, 2 if warning cause has been seen. */
@@ -1529,13 +1575,17 @@ function_types_compatible_p (const_tree
if (TYPE_VOLATILE (ret2))
ret2 = build_qualified_type (TYPE_MAIN_VARIANT (ret2),
TYPE_QUALS (ret2) & ~TYPE_QUAL_VOLATILE);
- val = comptypes_internal (ret1, ret2, enum_and_int_p);
+ val = comptypes_internal (ret1, ret2, enum_and_int_p, different_types_p);
if (val == 0)
return 0;
args1 = TYPE_ARG_TYPES (f1);
args2 = TYPE_ARG_TYPES (f2);
+ if (different_types_p != NULL
+ && (args1 == 0) != (args2 == 0))
+ *different_types_p = true;
+
/* An unspecified parmlist matches any specified parmlist
whose argument types don't need default promotions. */
@@ -1548,7 +1598,7 @@ function_types_compatible_p (const_tree
If they don't match, ask for a warning (but no error). */
if (TYPE_ACTUAL_ARG_TYPES (f1)
&& 1 != type_lists_compatible_p (args2, TYPE_ACTUAL_ARG_TYPES (f1),
- enum_and_int_p))
+ enum_and_int_p, different_types_p))
val = 2;
return val;
}
@@ -1558,23 +1608,25 @@ function_types_compatible_p (const_tree
return 0;
if (TYPE_ACTUAL_ARG_TYPES (f2)
&& 1 != type_lists_compatible_p (args1, TYPE_ACTUAL_ARG_TYPES (f2),
- enum_and_int_p))
+ enum_and_int_p, different_types_p))
val = 2;
return val;
}
/* Both types have argument lists: compare them and propagate results. */
- val1 = type_lists_compatible_p (args1, args2, enum_and_int_p);
+ val1 = type_lists_compatible_p (args1, args2, enum_and_int_p,
+ different_types_p);
return val1 != 1 ? val1 : val;
}
/* Check two lists of types for compatibility, returning 0 for
incompatible, 1 for compatible, or 2 for compatible with
- warning. ENUM_AND_INT_P is as in comptypes_internal. */
+ warning. ENUM_AND_INT_P and DIFFERENT_TYPES_P are as in
+ comptypes_internal. */
static int
type_lists_compatible_p (const_tree args1, const_tree args2,
- bool *enum_and_int_p)
+ bool *enum_and_int_p, bool *different_types_p)
{
/* 1 if no need for warning yet, 2 if warning cause has been seen. */
int val = 1;
@@ -1599,6 +1651,9 @@ type_lists_compatible_p (const_tree args
means there is supposed to be an argument
but nothing is specified about what type it has.
So match anything that self-promotes. */
+ if (different_types_p != NULL
+ && (a1 == 0) != (a2 == 0))
+ *different_types_p = true;
if (a1 == 0)
{
if (c_type_promotes_to (a2) != a2)
@@ -1613,8 +1668,11 @@ type_lists_compatible_p (const_tree args
else if (TREE_CODE (a1) == ERROR_MARK
|| TREE_CODE (a2) == ERROR_MARK)
;
- else if (!(newval = comptypes_internal (mv1, mv2, enum_and_int_p)))
+ else if (!(newval = comptypes_internal (mv1, mv2, enum_and_int_p,
+ different_types_p)))
{
+ if (different_types_p != NULL)
+ *different_types_p = true;
/* Allow wait (union {union wait *u; int *i} *)
and wait (union wait *) to be compatible. */
if (TREE_CODE (a1) == UNION_TYPE
@@ -1632,7 +1690,8 @@ type_lists_compatible_p (const_tree args
if (mv3 && mv3 != error_mark_node
&& TREE_CODE (mv3) != ARRAY_TYPE)
mv3 = TYPE_MAIN_VARIANT (mv3);
- if (comptypes_internal (mv3, mv2, enum_and_int_p))
+ if (comptypes_internal (mv3, mv2, enum_and_int_p,
+ different_types_p))
break;
}
if (memb == 0)
@@ -1653,7 +1712,8 @@ type_lists_compatible_p (const_tree args
if (mv3 && mv3 != error_mark_node
&& TREE_CODE (mv3) != ARRAY_TYPE)
mv3 = TYPE_MAIN_VARIANT (mv3);
- if (comptypes_internal (mv3, mv1, enum_and_int_p))
+ if (comptypes_internal (mv3, mv1, enum_and_int_p,
+ different_types_p))
break;
}
if (memb == 0)
--
Joseph S. Myers
joseph@codesourcery.com