[PATCH]: PR c/22476 -Wmissing-format-attribute [take 3]
Kaveh R. Ghazi
ghazi@caipclassic.rutgers.edu
Mon Jul 18 08:07:00 GMT 2005
> The warning in c_common_post_options for -Wmissing-format-attribute
> without -Wformat will need rewording, and "warning (0," in the patch
> should use OPT_Wmissing_format_attribute instead of 0.
This version addresses your comments above and passed regression
testing. This post for reference only, I'm going to split
-Wmissing-format-attribute and -Wformat next as per your message here:
http://gcc.gnu.org/ml/gcc-patches/2005-07/msg01092.html
--Kaveh
2005-07-16 Kaveh R. Ghazi <ghazi@caip.rutgers.edu>
PR c/22476
* c-opts.c (c_common_post_options): Update diagnostic for
-Wmissing-format-attribute.
* 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-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: Update.
diff -rup orig/egcc-CVS20050716/gcc/c-opts.c egcc-CVS20050716/gcc/c-opts.c
--- orig/egcc-CVS20050716/gcc/c-opts.c 2005-06-25 22:37:13.000000000 -0400
+++ egcc-CVS20050716/gcc/c-opts.c 2005-07-16 11:12:30.000000000 -0400
@@ -992,7 +992,7 @@ c_common_post_options (const char **pfil
warning (OPT_Wformat_security,
"-Wformat-security ignored without -Wformat");
warning (OPT_Wmissing_format_attribute,
- "-Wmissing-format-attribute ignored without -Wformat");
+ "-Wmissing-format-attribute is less effective without -Wformat");
}
/* C99 requires special handling of complex multiplication and division;
diff -rup orig/egcc-CVS20050716/gcc/c-typeck.c egcc-CVS20050716/gcc/c-typeck.c
--- orig/egcc-CVS20050716/gcc/c-typeck.c 2005-07-16 10:38:02.000000000 -0400
+++ egcc-CVS20050716/gcc/c-typeck.c 2005-07-16 10:57:01.000000000 -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-CVS20050716/gcc/doc/invoke.texi egcc-CVS20050716/gcc/doc/invoke.texi
--- orig/egcc-CVS20050716/gcc/doc/invoke.texi 2005-07-13 21:43:26.000000000 -0400
+++ egcc-CVS20050716/gcc/doc/invoke.texi 2005-07-16 10:51:40.000000000 -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
-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}).
+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.
+
+If @option{-Wformat} is enabled (possibly by @option{-Wall}), 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.
@item -Wno-multichar
@opindex Wno-multichar
diff -rup orig/egcc-CVS20050716/gcc/testsuite/gcc.dg/format/miss-3.c egcc-CVS20050716/gcc/testsuite/gcc.dg/format/miss-3.c
--- orig/egcc-CVS20050716/gcc/testsuite/gcc.dg/format/miss-3.c 2005-07-16 10:52:12.000000000 -0400
+++ egcc-CVS20050716/gcc/testsuite/gcc.dg/format/miss-3.c 2005-07-16 10:51:40.000000000 -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 -Wformat -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-CVS20050716/gcc/testsuite/gcc.dg/format/miss-4.c egcc-CVS20050716/gcc/testsuite/gcc.dg/format/miss-4.c
--- orig/egcc-CVS20050716/gcc/testsuite/gcc.dg/format/miss-4.c 2005-07-16 10:52:15.000000000 -0400
+++ egcc-CVS20050716/gcc/testsuite/gcc.dg/format/miss-4.c 2005-07-16 10:51:40.000000000 -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 -Wformat -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-CVS20050716/gcc/testsuite/gcc.dg/format/miss-5.c egcc-CVS20050716/gcc/testsuite/gcc.dg/format/miss-5.c
--- orig/egcc-CVS20050716/gcc/testsuite/gcc.dg/format/miss-5.c 2005-07-16 10:52:17.000000000 -0400
+++ egcc-CVS20050716/gcc/testsuite/gcc.dg/format/miss-5.c 2005-07-16 10:51:40.000000000 -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 -Wformat -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-CVS20050716/gcc/testsuite/gcc.dg/format/miss-6.c egcc-CVS20050716/gcc/testsuite/gcc.dg/format/miss-6.c
--- orig/egcc-CVS20050716/gcc/testsuite/gcc.dg/format/miss-6.c 2005-07-16 10:52:19.000000000 -0400
+++ egcc-CVS20050716/gcc/testsuite/gcc.dg/format/miss-6.c 2005-07-16 10:51:40.000000000 -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 -Wformat -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-CVS20050716/gcc/testsuite/gcc.dg/format/opt-6.c egcc-CVS20050716/gcc/testsuite/gcc.dg/format/opt-6.c
--- orig/egcc-CVS20050716/gcc/testsuite/gcc.dg/format/opt-6.c 2004-11-27 21:16:57.000000000 -0500
+++ egcc-CVS20050716/gcc/testsuite/gcc.dg/format/opt-6.c 2005-07-16 11:14:15.000000000 -0400
@@ -4,4 +4,4 @@
/* { dg-do compile } */
/* { dg-options "-Wmissing-format-attribute" } */
-/* { dg-warning "warning: -Wmissing-format-attribute ignored without -Wformat" "ignored" { target *-*-* } 0 } */
+/* { dg-warning "warning: -Wmissing-format-attribute is less effective without -Wformat" "ignored" { target *-*-* } 0 } */
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