re PR c++/5661 (Gcc 3.0.3 Seg faults compiling bad code)

PR c++/5661
	* cp-tree.h (variably_modified_type_p): New function.
	(grokdeclarator) Tighten check for variably modified types as
	fields.
	* pt.c (convert_template_argument): Do not allow variably modified
	types as template arguments.
	* tree.c (variably_modified_type_p): New function.

	PR c++/5661
	* g++.dg/ext/vlm1.C: New test.
	* g++.dg/ext/vlm2.C: Likewise.

From-SVN: r58060
This commit is contained in:
Mark Mitchell 2002-10-11 19:55:21 +00:00 committed by Mark Mitchell
parent 46dd38849b
commit dac45b5c09
8 changed files with 123 additions and 13 deletions

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@ -11,6 +11,14 @@
2002-10-11 Mark Mitchell <mark@codesourcery.com> 2002-10-11 Mark Mitchell <mark@codesourcery.com>
PR c++/5661
* cp-tree.h (variably_modified_type_p): New function.
(grokdeclarator) Tighten check for variably modified types as
fields.
* pt.c (convert_template_argument): Do not allow variably modified
types as template arguments.
* tree.c (variably_modified_type_p): New function.
* NEWS: Document removal of "new X = ..." extension. * NEWS: Document removal of "new X = ..." extension.
* class.c (initialize_array): Set TREE_HAS_CONSTRUCTOR on * class.c (initialize_array): Set TREE_HAS_CONSTRUCTOR on
brace-enclosed initializers. brace-enclosed initializers.

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@ -4179,6 +4179,7 @@ extern tree cxx_unsave_expr_now PARAMS ((tree));
extern tree cxx_maybe_build_cleanup PARAMS ((tree)); extern tree cxx_maybe_build_cleanup PARAMS ((tree));
extern void init_tree PARAMS ((void)); extern void init_tree PARAMS ((void));
extern int pod_type_p PARAMS ((tree)); extern int pod_type_p PARAMS ((tree));
extern bool variably_modified_type_p (tree);
extern int zero_init_p PARAMS ((tree)); extern int zero_init_p PARAMS ((tree));
extern tree canonical_type_variant PARAMS ((tree)); extern tree canonical_type_variant PARAMS ((tree));
extern void unshare_base_binfos PARAMS ((tree)); extern void unshare_base_binfos PARAMS ((tree));

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@ -10928,19 +10928,6 @@ grokdeclarator (declarator, declspecs, decl_context, initialized, attrlist)
type = create_array_type_for_decl (dname, type, size); type = create_array_type_for_decl (dname, type, size);
/* VLAs never work as fields. */
if (decl_context == FIELD && !processing_template_decl
&& TREE_CODE (type) == ARRAY_TYPE
&& TYPE_DOMAIN (type) != NULL_TREE
&& !TREE_CONSTANT (TYPE_MAX_VALUE (TYPE_DOMAIN (type))))
{
error ("size of member `%D' is not constant", dname);
/* Proceed with arbitrary constant size, so that offset
computations don't get confused. */
type = create_array_type_for_decl (dname, TREE_TYPE (type),
integer_one_node);
}
ctype = NULL_TREE; ctype = NULL_TREE;
} }
break; break;
@ -11420,6 +11407,14 @@ grokdeclarator (declarator, declspecs, decl_context, initialized, attrlist)
type = error_mark_node; type = error_mark_node;
} }
if (decl_context == FIELD
&& !processing_template_decl
&& variably_modified_type_p (type))
{
error ("data member may not have variably modified type `%T'", type);
type = error_mark_node;
}
if (explicitp == 1 || (explicitp && friendp)) if (explicitp == 1 || (explicitp && friendp))
{ {
/* [dcl.fct.spec] The explicit specifier shall only be used in /* [dcl.fct.spec] The explicit specifier shall only be used in

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@ -3467,6 +3467,16 @@ convert_template_argument (parm, arg, args, complain, i, in_decl)
val, t); val, t);
return error_mark_node; return error_mark_node;
} }
/* In order to avoid all sorts of complications, we do
not allow variably-modified types as template
arguments. */
if (variably_modified_type_p (val))
{
error ("template-argument `%T' is a variably modified type",
val);
return error_mark_node;
}
} }
} }
} }

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@ -1958,6 +1958,72 @@ pod_type_p (t)
return 1; return 1;
} }
/* Returns true if T is a variably modified type, in the sense of
C99.
In C99, a struct type is never variably modified because a VLA may
not appear as a structure member. However, in GNU C code like:
struct S { int i[f()]; };
is valid. Even though GNU C++ does not allow that, this function
may sometimes be used in the C front end, so it treats any type
with variable size in the same way that C99 treats VLAs.
In particular, a variably modified type is one that involves a type
with variable size. */
bool
variably_modified_type_p (tree type)
{
/* If TYPE itself has variable size, it is variably modified.
We do not yet have a representation of the C99 '[*]' syntax.
When a representation is chosen, this function should be modified
to test for that case as well. */
if (TYPE_SIZE (type)
&& TYPE_SIZE (type) != error_mark_node
&& TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
return true;
/* If TYPE is a pointer or reference, it is variably modified if and
only if the type pointed to is variably modified. */
if (TYPE_PTR_P (type)
|| TREE_CODE (type) == REFERENCE_TYPE)
return variably_modified_type_p (TREE_TYPE (type));
/* If TYPE is an array, it is variably modified if the array
elements are. (Note that the VLA case has alredy been checked
above). */
if (TREE_CODE (type) == ARRAY_TYPE)
return variably_modified_type_p (TREE_TYPE (type));
/* If TYPE is a pointer-to-member, it is variably modified if either
the class or the member are variably modified. */
if (TYPE_PTRMEM_P (type) || TYPE_PTRMEMFUNC_P (type))
return (variably_modified_type_p (TYPE_PTRMEM_CLASS_TYPE (type))
|| variably_modified_type_p (TYPE_PTRMEM_POINTED_TO_TYPE (type)));
/* If TYPE Is a function type, it is variably modified if any of the
parameters or the return type are variably modified. */
if (TREE_CODE (type) == FUNCTION_TYPE
|| TREE_CODE (type) == METHOD_TYPE)
{
tree parm;
if (variably_modified_type_p (TREE_TYPE (type)))
return true;
for (parm = TYPE_ARG_TYPES (type);
parm && parm != void_list_node;
parm = TREE_CHAIN (parm))
if (variably_modified_type_p (TREE_VALUE (parm)))
return true;
}
/* All other types are not variably modified. */
return false;
}
/* Returns 1 iff zero initialization of type T means actually storing /* Returns 1 iff zero initialization of type T means actually storing
zeros in it. */ zeros in it. */

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@ -1,5 +1,9 @@
2002-10-11 Mark Mitchell <mark@codesourcery.com> 2002-10-11 Mark Mitchell <mark@codesourcery.com>
PR c++/5661
* g++.dg/ext/vlm1.C: New test.
* g++.dg/ext/vlm2.C: Likewise.
* g++.dg/init/array1.C: Remove invalid braces. * g++.dg/init/array1.C: Remove invalid braces.
* g++.dg/init/brace1.C: New test. * g++.dg/init/brace1.C: New test.
* g++.dg/init/copy2.C: Likewise. * g++.dg/init/copy2.C: Likewise.

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@ -0,0 +1,13 @@
// { dg-options "" }
template <class T> struct A {};
struct B {
static const int s;
A<int[s]> a; // { dg-error "variably modified|no type" }
};
const int B::s=16;
B b;

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@ -0,0 +1,13 @@
// { dg-options "" }
int n;
struct Y
{
void f () {
typedef int X[n];
struct Z {
X x; // { dg-error "variably modified" }
};
}
};