On Sat, 27 Nov 2021 22:18:23 +0000
Daniil Stas <daniil.s...@posteo.net> wrote:
> This option is enabled by default when -Wformat option is enabled. A
> user can specify -Wno-format-int-precision to disable emitting
> warnings when passing an argument of an incompatible integer type to
> a 'd', 'i', 'b', 'B', 'o', 'u', 'x', or 'X' conversion specifier when
> it has the same precision as the expected type.
>
> Signed-off-by: Daniil Stas <daniil.s...@posteo.net>
>
> gcc/c-family/ChangeLog:
>
> * c-format.c (check_format_types): Don't emit warnings when
> passing an argument of an incompatible integer type to
> a 'd', 'i', 'b', 'B', 'o', 'u', 'x', or 'X' conversion
> specifier when it has the same precision as the expected type
> if -Wno-format-int-precision option is specified.
> * c.opt: Add -Wformat-int-precision option.
>
> gcc/ChangeLog:
>
> * doc/invoke.texi: Add -Wformat-int-precision option
> description.
>
> gcc/testsuite/ChangeLog:
>
> * c-c++-common/Wformat-int-precision-1.c: New test.
> * c-c++-common/Wformat-int-precision-2.c: New test.
> ---
> Changes for v4:
> - Added 'b' and 'B' format specifiers to the option descriptions.
>
> Changes for v3:
> - Added additional @code{} derictives to the documentation where
> needed.
> - Changed tests to run on "! long_neq_int" target instead of "lp64".
> - Added a test case to check that gcc still emits warnings for
> arguments with different precision even with
> -Wno-format-int-precision option enabled.
>
> Changes for v2:
> - Changed the option name to -Wformat-int-precision.
> - Changed the option description as was suggested by Martin.
> - Changed Wformat-int-precision-2.c to use dg-bogus instead of
> previous invalid syntax.
>
> gcc/c-family/c-format.c | 2 +-
> gcc/c-family/c.opt | 6 ++++++
> gcc/doc/invoke.texi | 17
> ++++++++++++++++- .../c-c++-common/Wformat-int-precision-1.c |
> 7 +++++++ .../c-c++-common/Wformat-int-precision-2.c | 8
> ++++++++ 5 files changed, 38 insertions(+), 2 deletions(-)
> create mode 100644
> gcc/testsuite/c-c++-common/Wformat-int-precision-1.c create mode
> 100644 gcc/testsuite/c-c++-common/Wformat-int-precision-2.c
>
> diff --git a/gcc/c-family/c-format.c b/gcc/c-family/c-format.c
> index e735e092043..c66787f931f 100644
> --- a/gcc/c-family/c-format.c
> +++ b/gcc/c-family/c-format.c
> @@ -4248,7 +4248,7 @@ check_format_types (const substring_loc
> &fmt_loc, && (!pedantic || i < 2)
> && char_type_flag)
> continue;
> - if (types->scalar_identity_flag
> + if ((types->scalar_identity_flag || !warn_format_int_precision)
> && (TREE_CODE (cur_type) == TREE_CODE (wanted_type)
> || (INTEGRAL_TYPE_P (cur_type)
> && INTEGRAL_TYPE_P (wanted_type)))
> diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
> index 4b8a094b206..d7d952765c6 100644
> --- a/gcc/c-family/c.opt
> +++ b/gcc/c-family/c.opt
> @@ -684,6 +684,12 @@ C ObjC C++ LTO ObjC++ Warning
> Alias(Wformat-overflow=, 1, 0) IntegerRange(0, 2) Warn about function
> calls with format strings that write past the end of the destination
> region. Same as -Wformat-overflow=1.
> +Wformat-int-precision
> +C ObjC C++ ObjC++ Var(warn_format_int_precision) Warning
> LangEnabledBy(C ObjC C++ ObjC++,Wformat=,warn_format >= 1, 0) +Warn
> when passing an argument of an incompatible integer type to a 'd',
> 'i', +'b', 'B', 'o', 'u', 'x', or 'X' conversion specifier even when
> it has the same +precision as the expected type. +
> Wformat-security
> C ObjC C++ ObjC++ Var(warn_format_security) Warning LangEnabledBy(C
> ObjC C++ ObjC++,Wformat=, warn_format >= 2, 0) Warn about possible
> security problems with format functions. diff --git
> a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index
> 3bddfbaae6a..94a7ad96c50 100644 --- a/gcc/doc/invoke.texi
> +++ b/gcc/doc/invoke.texi
> @@ -351,7 +351,7 @@ Objective-C and Objective-C++ Dialects}.
> -Werror -Werror=* -Wexpansion-to-defined -Wfatal-errors @gol
> -Wfloat-conversion -Wfloat-equal -Wformat -Wformat=2 @gol
> -Wno-format-contains-nul -Wno-format-extra-args @gol
> --Wformat-nonliteral -Wformat-overflow=@var{n} @gol
> +-Wformat-nonliteral -Wformat-overflow=@var{n}
> -Wformat-int-precision @gol -Wformat-security -Wformat-signedness
> -Wformat-truncation=@var{n} @gol -Wformat-y2k -Wframe-address @gol
> -Wframe-larger-than=@var{byte-size} -Wno-free-nonheap-object @gol
> @@ -6122,6 +6122,21 @@ If @option{-Wformat} is specified, also warn
> if the format string is not a string literal and so cannot be
> checked, unless the format function takes its format arguments as a
> @code{va_list}.
> +@item -Wformat-int-precision
> +@opindex Wformat-int-precision
> +@opindex Wno-format-int-precision
> +Warn when passing an argument of an incompatible integer type to
> +a @samp{d}, @samp{i}, @samp{b}, @samp{B}, @samp{o}, @samp{u},
> @samp{x}, +or @samp{X} conversion specifier even when it has the same
> precision as +the expected type. For example, on targets where
> @code{int64_t} is a typedef +for @code{long}, the warning is issued
> for the @code{printf} call below even +when both @code{long} and
> @code{long long} have the same size and precision. +
> +@smallexample
> + extern int64_t n;
> + printf ("%lli", n);
> +@end smallexample
> +
> @item -Wformat-security
> @opindex Wformat-security
> @opindex Wno-format-security
> diff --git a/gcc/testsuite/c-c++-common/Wformat-int-precision-1.c
> b/gcc/testsuite/c-c++-common/Wformat-int-precision-1.c new file mode
> 100644 index 00000000000..a06e047c933
> --- /dev/null
> +++ b/gcc/testsuite/c-c++-common/Wformat-int-precision-1.c
> @@ -0,0 +1,7 @@
> +/* { dg-do compile { target { ! long_neq_int } } } */
> +/* { dg-options "-Wformat" } */
> +
> +void test ()
> +{
> + __builtin_printf ("%d\n", (long) 1); /* { dg-warning "expects
> argument of type" } */ +}
> diff --git a/gcc/testsuite/c-c++-common/Wformat-int-precision-2.c
> b/gcc/testsuite/c-c++-common/Wformat-int-precision-2.c new file mode
> 100644 index 00000000000..e9b41b4f42e
> --- /dev/null
> +++ b/gcc/testsuite/c-c++-common/Wformat-int-precision-2.c
> @@ -0,0 +1,8 @@
> +/* { dg-do compile { target { ! long_neq_int } } } */
> +/* { dg-options "-Wformat -Wno-format-int-precision" } */
> +
> +void test ()
> +{
> + __builtin_printf ("%d\n", (long) 1); /* { dg-bogus "expects
> argument of type" } */
> + __builtin_printf ("%d\n", (long long) 1); /* { dg-warning "expects
> argument of type" "" { target int32 } } */ +}
Hi Joseph,
Can your review this patch?
Thank you
