attribs.c (decl_attributes): Possibly call insert_default_attributes to insert default attributes on...

	* attribs.c (decl_attributes): Possibly call
	insert_default_attributes to insert default attributes on
	functions in a lazy manner.
	* builtin-attrs.def: New file; define the default format and
	format_arg attributes.
	* c-common.c (c_format_attribute_table): Move to earlier in the
	file.
	(c_common_nodes_and_builtins): Initialize format_attribute_table.
	(enum built_in_attribute, built_in_attributes,
	c_attrs_initialized, c_init_attributes,
	c_common_insert_default_attributes): New.
	(c_common_lang_init): Don't initialize format_attribute_table.  Do
	call c_init_attributes.
	* Makefile.in (c-common.o): Depend on builtin-attrs.def.
	* c-common.h (init_function_format_info): Don't declare.
	(c_common_insert_default_attributes): Declare.
	* c-decl.c (implicitly_declare, builtin_function): Call
	decl_attributes.
	(init_decl_processing): Don't call init_function_format_info.
	(insert_default_attributes): New.
	* c-format.c (handle_format_attribute,
	handle_format_arg_attribute): Be quiet about inappropriate
	declaration when applying default attributes.
	(init_function_format_info): Remove.
	* tree.h (enum attribute_flags): Add ATTR_FLAG_BUILT_IN.
	(insert_default_attributes): Declare.

cp:
	* decl.c (init_decl_processing): Don't call
	init_function_format_info.  Initialize lang_attribute_table
	earlier.
	(builtin_function): Call decl_attributes.
	(insert_default_attributes): New.

testsuite:
	* gcc.dg/format/attr-5.c, gcc.dg/format/attr-6.c: New tests.

From-SVN: r45942

2 files changed, 49 insertions, 0 deletions

diff --git a/gcc/testsuite/gcc.dg/format/attr-5.c b/gcc/testsuite/gcc.dg/format/attr-5.c
new file mode 100644
index 0000000..a4e9634
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/format/attr-5.c
@@ -0,0 +1,28 @@
+/* Test for format attributes: test default attributes are silently ignored
+   when a function is redeclared in an inappropriate manner.  */
+/* Origin: Joseph Myers <jsm28@cam.ac.uk> */
+/* { dg-do compile } */
+/* { dg-options "-std=gnu99 -Wformat" } */
+
+/* We can't #include "format.h" here.  */
+
+/* This scanf declaration is static, so can't be the system function.  */
+static int scanf(const char *restrict, ...);
+
+/* This sscanf declaration doesn't have variable arguments, so isn't
+   compatible with a format attribute.  */
+extern int sscanf(const char *restrict, const char *restrict, int *);
+
+void
+foo (const char *s, int *p)
+{
+  scanf("%ld", p); /* { dg-bogus "format" "static" } */
+  sscanf(s, "%ld", p); /* { dg-bogus "format" "wrong type" } */
+}
+
+/* Dummy definition of scanf.  */
+static int
+scanf (const char *restrict fmt, ...)
+{
+  return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/format/attr-6.c b/gcc/testsuite/gcc.dg/format/attr-6.c
new file mode 100644
index 0000000..4e95cfb
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/format/attr-6.c
@@ -0,0 +1,21 @@
+/* Test for format attributes: test default attributes are applied
+   to implicit declarations.  */
+/* Origin: Joseph Myers <jsm28@cam.ac.uk> */
+/* { dg-do compile } */
+/* { dg-options "-std=gnu89 -Wformat" } */
+
+/* We can't #include "format.h" here.  */
+
+/* Technically, none of the format functions should be implicitly declared;
+   either the implicit type is wrong, the function has variable arguments
+   or it requires a type declared in a header.  However, some bad programming
+   practice uses implicit declarations of some of these functions.
+
+   Note that printf is not used in this test because of the declaration
+   of it as a built-in function.  */
+
+void
+foo (const char *s, int *p)
+{
+  scanf("%ld", p); /* { dg-warning "format" "implicit scanf" } */
+}