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', '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', '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. --- This is an update of patch "c-format: Add -Wformat-same-precision option [PR80060]". The changes comparing to the first patch version: - changed the option name to -Wformat-int-precision - changed the option description as was suggested by Martin - changed Wformat-int-precision-2.c to used dg-bogus instead of previous invalid syntax I also tried to combine the tests into one file with #pragma GCC diagnostic, but looks like it's not possible. I want to test that when passing just -Wformat option everything works as before my patch by default. And then in another test case to check that passing -Wno-format-int-precision disables the warning. But looks like in GCC you can't toggle the warnings such as -Wno-format-int-precision individually but only can disable the general -Wformat option that will disable all the formatting warnings together, which is not the proper test. 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 | 7 +++++++ 5 files changed, 37 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 ca66c81f716..dd4436929f8 100644 --- a/gcc/c-family/c-format.c +++ b/gcc/c-family/c-format.c @@ -4243,7 +4243,7 @@ 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 06457ac739e..f5b4af3f3f6 100644 --- a/gcc/c-family/c.opt +++ b/gcc/c-family/c.opt @@ -660,6 +660,12 @@ 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', +'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 8b3ebcfbc4f..05dec6ba832 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -348,7 +348,7 @@ 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 @@ -6056,6 +6056,21 @@ 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{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 int64_t is a typedef for long, the warning +is issued for the printf call below even when both long and 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..fbc11e4200a --- /dev/null +++ b/gcc/testsuite/c-c++-common/Wformat-int-precision-1.c @@ -0,0 +1,7 @@ +/* { dg-do compile { target lp64 } } */ +/* { dg-options "-Wformat" } */ + +void test () +{ + __builtin_printf ("%lu\n", (long 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..63536bf5ff2 --- /dev/null +++ b/gcc/testsuite/c-c++-common/Wformat-int-precision-2.c @@ -0,0 +1,7 @@ +/* { dg-do compile { target lp64 } } */ +/* { dg-options "-Wformat -Wno-format-int-precision" } */ + +void test () +{ + __builtin_printf ("%lu\n", (long long) 1); /* { dg-bogus "expects argument of type" } */ +} -- 2.33.0