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[PATCH]: PR c/22476 -Wmissing-format-attribute [take 4]
> In principle it would be best for the options to be completely
> independent. That is, check_function_arguments would call
> check_function_format if either option is enabled, and
> check_function_format would then only call check_format_info if
> -Wformat is enabled. (Plus of course removal of the warning for
> -Wmissing-format-attribute on its own, updating of the documentation
> accordingly, removal of gcc.dg/format/opt-6.c which tests for the
> warning and adding a test that -Wmissing-format-attribute on its own
> enables the current warnings.)
This revision of my patch implements your suggestions above.
Bootstraped and tested on x86_64-unknown-linux-gnu, no regressions.
Okay for 4.2? Okay for 4.1?
Thanks,
--Kaveh
2005-07-18 Kaveh R. Ghazi <ghazi@caip.rutgers.edu>
PR c/22476
* c-common.c (check_function_arguments): Call
'check_function_format' if either -Wformat or
-Wmissing-format-attribute are specified.
* c-format.c (check_function_format): Check -Wformat before
calling 'check_format_info'.
* c-opts.c (c_common_post_options): Don't warn for
-Wmissing-format-attribute without -Wformat.
* c-typeck.c (convert_for_assignment): Detect additional cases for
-Wmissing-format-attribute.
* doc/invoke.texi (-Wmissing-format-attribute): Document new
behavior.
testsuite:
* gcc.dg/format/miss-1.c, gcc.dg/format/miss-2.c: Don't
specify -Wformat for these tests.
* gcc.dg/format/miss-3.c, gcc.dg/format/miss-4.c,
gcc.dg/format/miss-5.c, gcc.dg/format/miss-6.c: New.
* gcc.dg/format/opt-6.c: Delete.
diff -rup orig/egcc-CVS20050718/gcc/c-common.c egcc-CVS20050718/gcc/c-common.c
--- orig/egcc-CVS20050718/gcc/c-common.c 2005-07-15 23:18:30.000000000 -0400
+++ egcc-CVS20050718/gcc/c-common.c 2005-07-18 04:56:10.000000000 -0400
@@ -5505,11 +5505,11 @@ check_function_arguments (tree attrs, tr
/* Check for errors in format strings. */
- if (warn_format)
- {
+ if (warn_format || warn_missing_format_attribute)
check_function_format (attrs, params);
- check_function_sentinel (attrs, params, typelist);
- }
+
+ if (warn_format)
+ check_function_sentinel (attrs, params, typelist);
}
/* Generic argument checking recursion routine. PARAM is the argument to
diff -rup orig/egcc-CVS20050718/gcc/c-format.c egcc-CVS20050718/gcc/c-format.c
--- orig/egcc-CVS20050718/gcc/c-format.c 2005-07-03 21:40:00.000000000 -0400
+++ egcc-CVS20050718/gcc/c-format.c 2005-07-18 04:59:20.000000000 -0400
@@ -864,7 +864,8 @@ check_function_format (tree attrs, tree
/* Yup; check it. */
function_format_info info;
decode_format_attr (TREE_VALUE (a), &info, 1);
- check_format_info (&info, params);
+ if (warn_format)
+ check_format_info (&info, params);
if (warn_missing_format_attribute && info.first_arg_num == 0
&& (format_types[info.format_type].flags
& (int) FMT_FLAG_ARG_CONVERT))
diff -rup orig/egcc-CVS20050718/gcc/c-opts.c egcc-CVS20050718/gcc/c-opts.c
--- orig/egcc-CVS20050718/gcc/c-opts.c 2005-06-25 22:37:13.000000000 -0400
+++ egcc-CVS20050718/gcc/c-opts.c 2005-07-18 05:00:27.000000000 -0400
@@ -991,8 +991,6 @@ c_common_post_options (const char **pfil
"-Wformat-nonliteral ignored without -Wformat");
warning (OPT_Wformat_security,
"-Wformat-security ignored without -Wformat");
- warning (OPT_Wmissing_format_attribute,
- "-Wmissing-format-attribute ignored without -Wformat");
}
/* C99 requires special handling of complex multiplication and division;
diff -rup orig/egcc-CVS20050718/gcc/c-typeck.c egcc-CVS20050718/gcc/c-typeck.c
--- orig/egcc-CVS20050718/gcc/c-typeck.c 2005-07-16 10:38:02.000000000 -0400
+++ egcc-CVS20050718/gcc/c-typeck.c 2005-07-18 04:53:25.000000000 -0400
@@ -3793,6 +3793,55 @@ convert_for_assignment (tree type, tree
warning (OPT_Wc___compat, "request for implicit conversion from "
"%qT to %qT not permitted in C++", rhstype, type);
+ /* Check if the right-hand side has a format attribute but the
+ left-hand side doesn't. */
+ if (warn_missing_format_attribute)
+ {
+ tree rattrs = TYPE_ATTRIBUTES (ttr), ra;
+ for (ra = rattrs; ra; ra = TREE_CHAIN (ra))
+ {
+ if (is_attribute_p ("format", TREE_PURPOSE (ra)))
+ break;
+ }
+ if (ra)
+ {
+ tree lattrs = TYPE_ATTRIBUTES (ttl), la;
+ for (la = lattrs; la; la = TREE_CHAIN (la))
+ {
+ if (is_attribute_p ("format", TREE_PURPOSE (la)))
+ break;
+ }
+ if (!la)
+ switch (errtype)
+ {
+ case ic_argpass:
+ case ic_argpass_nonproto:
+ warning (OPT_Wmissing_format_attribute,
+ "argument %d of %qE might be "
+ "a candidate for a format attribute",
+ parmnum, rname);
+ break;
+ case ic_assign:
+ warning (OPT_Wmissing_format_attribute,
+ "assignment left-hand side might be "
+ "a candidate for a format attribute");
+ break;
+ case ic_init:
+ warning (OPT_Wmissing_format_attribute,
+ "initialization left-hand side might be "
+ "a candidate for a format attribute");
+ break;
+ case ic_return:
+ warning (OPT_Wmissing_format_attribute,
+ "return type might be "
+ "a candidate for a format attribute");
+ break;
+ default:
+ gcc_unreachable ();
+ }
+ }
+ }
+
/* Any non-function converts to a [const][volatile] void *
and vice versa; otherwise, targets must be the same.
Meanwhile, the lhs target must have all the qualifiers of the rhs. */
diff -rup orig/egcc-CVS20050718/gcc/doc/invoke.texi egcc-CVS20050718/gcc/doc/invoke.texi
--- orig/egcc-CVS20050718/gcc/doc/invoke.texi 2005-07-13 21:43:26.000000000 -0400
+++ egcc-CVS20050718/gcc/doc/invoke.texi 2005-07-18 05:01:55.000000000 -0400
@@ -3126,14 +3126,23 @@ hosted C environments.
@item -Wmissing-format-attribute
@opindex Wmissing-format-attribute
@opindex Wformat
-If @option{-Wformat} is enabled, also warn about functions which might be
-candidates for @code{format} attributes. Note these are only possible
-candidates, not absolute ones. GCC will guess that @code{format}
-attributes might be appropriate for any function that calls a function
-like @code{vprintf} or @code{vscanf}, but this might not always be the
+Warn about function pointers which might be candidates for @code{format}
+attributes. Note these are only possible candidates, not absolute ones.
+GCC will guess that function pointers with @code{format} attributes that
+are used in assignment, initialization, parameter passing or return
+statements should have a corresponding @code{format} attribute in the
+resulting type. I.e.@: the left-hand side of the assignment or
+initialization, the type of the parameter variable, or the return type
+of the containing function respectively should also have a @code{format}
+attribute to avoid the warning.
+
+GCC will also warn about function definitions which might be
+candidates for @code{format} attributes. Again, these are only
+possible candidates. GCC will guess that @code{format} attributes
+might be appropriate for any function that calls a function like
+@code{vprintf} or @code{vscanf}, but this might not always be the
case, and some functions for which @code{format} attributes are
-appropriate may not be detected. This option has no effect unless
-@option{-Wformat} is enabled (possibly by @option{-Wall}).
+appropriate may not be detected.
@item -Wno-multichar
@opindex Wno-multichar
diff -rup orig/egcc-CVS20050718/gcc/testsuite/gcc.dg/format/miss-1.c egcc-CVS20050718/gcc/testsuite/gcc.dg/format/miss-1.c
--- orig/egcc-CVS20050718/gcc/testsuite/gcc.dg/format/miss-1.c 2001-01-07 05:44:59.000000000 -0500
+++ egcc-CVS20050718/gcc/testsuite/gcc.dg/format/miss-1.c 2005-07-18 05:02:27.000000000 -0400
@@ -1,7 +1,7 @@
/* Test for warnings for missing format attributes. */
/* Origin: Joseph Myers <jsm28@cam.ac.uk> */
/* { dg-do compile } */
-/* { dg-options "-std=gnu99 -Wformat -Wmissing-format-attribute" } */
+/* { dg-options "-std=gnu99 -Wmissing-format-attribute" } */
#include "format.h"
diff -rup orig/egcc-CVS20050718/gcc/testsuite/gcc.dg/format/miss-2.c egcc-CVS20050718/gcc/testsuite/gcc.dg/format/miss-2.c
--- orig/egcc-CVS20050718/gcc/testsuite/gcc.dg/format/miss-2.c 2001-01-07 05:44:59.000000000 -0500
+++ egcc-CVS20050718/gcc/testsuite/gcc.dg/format/miss-2.c 2005-07-18 05:02:35.000000000 -0400
@@ -2,7 +2,7 @@
relevant parameters for a format attribute; see c/1017. */
/* Origin: Joseph Myers <jsm28@cam.ac.uk> */
/* { dg-do compile } */
-/* { dg-options "-std=gnu99 -Wformat -Wmissing-format-attribute" } */
+/* { dg-options "-std=gnu99 -Wmissing-format-attribute" } */
#include "format.h"
diff -rup orig/egcc-CVS20050718/gcc/testsuite/gcc.dg/format/miss-3.c egcc-CVS20050718/gcc/testsuite/gcc.dg/format/miss-3.c
--- orig/egcc-CVS20050718/gcc/testsuite/gcc.dg/format/miss-3.c 2005-07-18 05:04:35.000000000 -0400
+++ egcc-CVS20050718/gcc/testsuite/gcc.dg/format/miss-3.c 2005-07-18 05:02:42.000000000 -0400
@@ -0,0 +1,26 @@
+/* Test warnings for missing format attributes on function pointers. */
+/* Origin: Kaveh Ghazi <ghazi@caip.rutgers.edu> */
+/* { dg-do compile } */
+/* { dg-options "-std=gnu99 -Wmissing-format-attribute" } */
+
+#include "format.h"
+
+typedef void (*noattr_t) (const char *, ...);
+typedef noattr_t __attribute__ ((__format__(__printf__, 1, 2))) attr_t;
+
+typedef void (*vnoattr_t) (const char *, va_list);
+typedef vnoattr_t __attribute__ ((__format__(__printf__, 1, 0))) vattr_t;
+
+void
+foo1 (noattr_t na, attr_t a, vnoattr_t vna, vattr_t va)
+{
+ noattr_t na1 = na;
+ noattr_t na2 = a; /* { dg-warning "candidate" "initialization warning" } */
+ attr_t a1 = na;
+ attr_t a2 = a;
+
+ vnoattr_t vna1 = vna;
+ vnoattr_t vna2 = va; /* { dg-warning "candidate" "initialization warning" } */
+ vattr_t va1 = vna;
+ vattr_t va2 = va;
+}
diff -rup orig/egcc-CVS20050718/gcc/testsuite/gcc.dg/format/miss-4.c egcc-CVS20050718/gcc/testsuite/gcc.dg/format/miss-4.c
--- orig/egcc-CVS20050718/gcc/testsuite/gcc.dg/format/miss-4.c 2005-07-18 05:04:38.000000000 -0400
+++ egcc-CVS20050718/gcc/testsuite/gcc.dg/format/miss-4.c 2005-07-18 05:02:46.000000000 -0400
@@ -0,0 +1,32 @@
+/* Test warnings for missing format attributes on function pointers. */
+/* Origin: Kaveh Ghazi <ghazi@caip.rutgers.edu> */
+/* { dg-do compile } */
+/* { dg-options "-std=gnu99 -Wmissing-format-attribute" } */
+
+#include "format.h"
+
+typedef void (*noattr_t) (const char *, ...);
+typedef noattr_t __attribute__ ((__format__(__printf__, 1, 2))) attr_t;
+
+typedef void (*vnoattr_t) (const char *, va_list);
+typedef vnoattr_t __attribute__ ((__format__(__printf__, 1, 0))) vattr_t;
+
+void
+foo1 (noattr_t na, attr_t a, vnoattr_t vna, vattr_t va)
+{
+ noattr_t na1, na2;
+ attr_t a1, a2;
+
+ vnoattr_t vna1, vna2;
+ vattr_t va1, va2;
+
+ na1 = na;
+ na2 = a; /* { dg-warning "candidate" "assignment warning" } */
+ a1 = na;
+ a2 = a;
+
+ vna1 = vna;
+ vna2 = va; /* { dg-warning "candidate" "assignment warning" } */
+ va1 = vna;
+ va1 = va;
+}
diff -rup orig/egcc-CVS20050718/gcc/testsuite/gcc.dg/format/miss-5.c egcc-CVS20050718/gcc/testsuite/gcc.dg/format/miss-5.c
--- orig/egcc-CVS20050718/gcc/testsuite/gcc.dg/format/miss-5.c 2005-07-18 05:04:40.000000000 -0400
+++ egcc-CVS20050718/gcc/testsuite/gcc.dg/format/miss-5.c 2005-07-18 05:02:56.000000000 -0400
@@ -0,0 +1,48 @@
+/* Test warnings for missing format attributes on function pointers. */
+/* Origin: Kaveh Ghazi <ghazi@caip.rutgers.edu> */
+/* { dg-do compile } */
+/* { dg-options "-std=gnu99 -Wmissing-format-attribute" } */
+
+#include "format.h"
+
+typedef void (*noattr_t) (const char *, ...);
+typedef noattr_t __attribute__ ((__format__(__printf__, 1, 2))) attr_t;
+
+typedef void (*vnoattr_t) (const char *, va_list);
+typedef vnoattr_t __attribute__ ((__format__(__printf__, 1, 0))) vattr_t;
+
+noattr_t
+foo1 (noattr_t na, attr_t a, int i)
+{
+ if (i)
+ return na;
+ else
+ return a; /* { dg-warning "candidate" "return type warning" } */
+}
+
+attr_t
+foo2 (noattr_t na, attr_t a, int i)
+{
+ if (i)
+ return na;
+ else
+ return a;
+}
+
+vnoattr_t
+foo3 (vnoattr_t vna, vattr_t va, int i)
+{
+ if (i)
+ return vna;
+ else
+ return va; /* { dg-warning "candidate" "return type warning" } */
+}
+
+vattr_t
+foo4 (vnoattr_t vna, vattr_t va, int i)
+{
+ if (i)
+ return vna;
+ else
+ return va;
+}
diff -rup orig/egcc-CVS20050718/gcc/testsuite/gcc.dg/format/miss-6.c egcc-CVS20050718/gcc/testsuite/gcc.dg/format/miss-6.c
--- orig/egcc-CVS20050718/gcc/testsuite/gcc.dg/format/miss-6.c 2005-07-18 05:04:42.000000000 -0400
+++ egcc-CVS20050718/gcc/testsuite/gcc.dg/format/miss-6.c 2005-07-18 05:03:04.000000000 -0400
@@ -0,0 +1,31 @@
+/* Test warnings for missing format attributes on function pointers. */
+/* Origin: Kaveh Ghazi <ghazi@caip.rutgers.edu> */
+/* { dg-do compile } */
+/* { dg-options "-std=gnu99 -Wmissing-format-attribute" } */
+
+#include "format.h"
+
+typedef void (*noattr_t) (const char *, ...);
+typedef noattr_t __attribute__ ((__format__(__printf__, 1, 2))) attr_t;
+
+typedef void (*vnoattr_t) (const char *, va_list);
+typedef vnoattr_t __attribute__ ((__format__(__printf__, 1, 0))) vattr_t;
+
+extern void foo1 (noattr_t);
+extern void foo2 (attr_t);
+extern void foo3 (vnoattr_t);
+extern void foo4 (vattr_t);
+
+void
+foo (noattr_t na, attr_t a, vnoattr_t vna, vattr_t va)
+{
+ foo1 (na);
+ foo1 (a); /* { dg-warning "candidate" "parameter passing warning" } */
+ foo2 (na);
+ foo2 (a);
+
+ foo3 (vna);
+ foo3 (va); /* { dg-warning "candidate" "parameter passing warning" } */
+ foo4 (vna);
+ foo4 (va);
+}
diff -rup orig/egcc-CVS20050718/gcc/testsuite/gcc.dg/format/opt-6.c egcc-CVS20050718/gcc/testsuite/gcc.dg/format/opt-6.c
--- orig/egcc-CVS20050718/gcc/testsuite/gcc.dg/format/opt-6.c 2004-11-27 21:16:57.000000000 -0500
+++ egcc-CVS20050718/gcc/testsuite/gcc.dg/format/opt-6.c 2005-07-18 05:04:15.000000000 -0400
@@ -1,7 +0,0 @@
-/* Test diagnostics for options used on their own without
- -Wformat. -Wmissing-format-attribute. */
-/* Origin: Joseph Myers <joseph@codesourcery.com> */
-/* { dg-do compile } */
-/* { dg-options "-Wmissing-format-attribute" } */
-
-/* { dg-warning "warning: -Wmissing-format-attribute ignored without -Wformat" "ignored" { target *-*-* } 0 } */