Em Wed, Feb 17, 2021 at 07:58:30PM +0800, Jianlin Lv escreveu:
> gcc version: 11.0.0 20210208 (experimental) (GCC)
>
> Following build error on arm64:
>
> .......
> In function ‘printf’,
> inlined from ‘regs_dump__printf’ at util/session.c:1141:3,
> inlined from ‘regs__printf’ at util/session.c:1169:2:
> /usr/include/aarch64-linux-gnu/bits/stdio2.h:107:10: \
> error: ‘%-5s’ directive argument is null [-Werror=format-overflow=]
>
> 107 | return __printf_chk (__USE_FORTIFY_LEVEL - 1, __fmt, \
> __va_arg_pack ());
>
> ......
> In function ‘fprintf’,
> inlined from ‘perf_sample__fprintf_regs.isra’ at \
> builtin-script.c:622:14:
> /usr/include/aarch64-linux-gnu/bits/stdio2.h:100:10: \
> error: ‘%5s’ directive argument is null [-Werror=format-overflow=]
> 100 | return __fprintf_chk (__stream, __USE_FORTIFY_LEVEL - 1, __fmt,
> 101 | __va_arg_pack ());
>
> cc1: all warnings being treated as errors
> .......
>
> This patch fixes Wformat-overflow warnings. Add helper function to
> convert NULL to "unknown".
I think this is the right approach, but since both return a string, it
is strange that only one of them have its _str() at the end, what we
usually do in such cases is to have:
const char *__perf_reg_name(int id)
{
return NULL if id unknown;
}
And:
static inline const char *perf_reg_name(int id)
{
const char *name = __perf_reg_name(id);
return name ?: "unknown";
}
Ok?
- Arnaldo
> Signed-off-by: Jianlin Lv <[email protected]>
> ---
> v2: Add ternary operator to avoid similar errors in other arch.
> v3: Declared reg_name in inner block.
> v4: Add helper function: perf_reg_name_str, update changelog.
> ---
> tools/perf/builtin-script.c | 2 +-
> tools/perf/util/perf_regs.h | 11 ++++++++++-
> .../perf/util/scripting-engines/trace-event-python.c | 2 +-
> tools/perf/util/session.c | 2 +-
> 4 files changed, 13 insertions(+), 4 deletions(-)
>
> diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
> index 42dad4a0f8cf..35cddca2c7a7 100644
> --- a/tools/perf/builtin-script.c
> +++ b/tools/perf/builtin-script.c
> @@ -643,7 +643,7 @@ static int perf_sample__fprintf_regs(struct regs_dump *regs, uint64_t mask,
>
> for_each_set_bit(r, (unsigned long *) &mask, sizeof(mask) * 8) {
> u64 val = regs->regs[i++];
> - printed += fprintf(fp, "%5s:0x%"PRIx64" ", perf_reg_name(r), val);
> + printed += fprintf(fp, "%5s:0x%"PRIx64" ", perf_reg_name_str(r), val);
> }
>
> return printed;
> diff --git a/tools/perf/util/perf_regs.h b/tools/perf/util/perf_regs.h
> index a45499126184..e4a0a6f5408e 100644
> --- a/tools/perf/util/perf_regs.h
> +++ b/tools/perf/util/perf_regs.h
> @@ -33,13 +33,22 @@ extern const struct sample_reg sample_reg_masks[];
>
> int perf_reg_value(u64 *valp, struct regs_dump *regs, int id);
>
> +static inline const char *perf_reg_name_str(int id)
> +{
> + const char *str = perf_reg_name(id);
> +
> + if (!str)
> + return "unknown";
> + return str;
> +}
> +
> #else
> #define PERF_REGS_MASK 0
> #define PERF_REGS_MAX 0
>
> #define DWARF_MINIMAL_REGS PERF_REGS_MASK
>
> -static inline const char *perf_reg_name(int id __maybe_unused)
> +static inline const char *perf_reg_name_str(int id __maybe_unused)
> {
> return "unknown";
> }
> diff --git a/tools/perf/util/scripting-engines/trace-event-python.c b/tools/perf/util/scripting-engines/trace-event-python.c
> index c83c2c6564e0..361307026485 100644
> --- a/tools/perf/util/scripting-engines/trace-event-python.c
> +++ b/tools/perf/util/scripting-engines/trace-event-python.c
> @@ -702,7 +702,7 @@ static int regs_map(struct regs_dump *regs, uint64_t mask, char *bf, int size)
>
> printed += scnprintf(bf + printed, size - printed,
> "%5s:0x%" PRIx64 " ",
> - perf_reg_name(r), val);
> + perf_reg_name_str(r), val);
> }
>
> return printed;
> diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
> index 25adbcce0281..0737d3e7e698 100644
> --- a/tools/perf/util/session.c
> +++ b/tools/perf/util/session.c
> @@ -1140,7 +1140,7 @@ static void regs_dump__printf(u64 mask, u64 *regs)
> u64 val = regs[i++];
>
> printf(".... %-5s 0x%016" PRIx64 "\n",
> - perf_reg_name(rid), val);
> + perf_reg_name_str(rid), val);
> }
> }
>
> --
> 2.25.1
>
--
- Arnaldo