On Sep 22 2021, Florian Weimer via Libc-alpha wrote:
> Instead of checking a pointer argument for NULL, use helper macros
> defined differently in the non-positional and positional cases.
> This avoids frequent conditional checks and a GCC 12 warning
> about comparing pointers against NULL which cannot be NULL.
Ok.
> @@ -1545,8 +1474,28 @@ vfprintf (FILE *s, const CHAR_T *format, va_list ap, unsigned int mode_flags)
> /* Process current format. */
> while (1)
> {
> - process_arg (((struct printf_spec *) NULL));
> - process_string_arg (((struct printf_spec *) NULL));
> +#define PROCESS_ARG_INT() va_arg (ap, int)
> +#define PROCESS_ARG_LONG_INT() va_arg (ap, long int)
> +#define PROCESS_ARG_LONG_LONG_INT() va_arg (ap, long long int)
> +#define PROCESS_ARG_POINTER() va_arg (ap, void *)
> +#define PROCESS_ARG_STRING() va_arg (ap, const char *)
> +#define PROCESS_ARG_UNSIGNED_INT() va_arg (ap, unsigned int)
> +#define PROCESS_ARG_UNSIGNED_LONG_INT() va_arg (ap, unsigned long int)
> +#define PROCESS_ARG_UNSIGNED_LONG_LONG_INT() va_arg (ap, unsigned long long int)
> +#define PROCESS_ARG_WCHAR_T() va_arg (ap, wchar_t)
> +#define PROCESS_ARG_WSTRING() va_arg (ap, const wchar_t *)
I think it would be nicer to spell these macros in lower case.
Andreas.
* Andreas Schwab:
> On Sep 22 2021, Florian Weimer via Libc-alpha wrote:
>
>> Instead of checking a pointer argument for NULL, use helper macros
>> defined differently in the non-positional and positional cases.
>> This avoids frequent conditional checks and a GCC 12 warning
>> about comparing pointers against NULL which cannot be NULL.
>
> Ok.
>
>> @@ -1545,8 +1474,28 @@ vfprintf (FILE *s, const CHAR_T *format, va_list ap, unsigned int mode_flags)
>> /* Process current format. */
>> while (1)
>> {
>> - process_arg (((struct printf_spec *) NULL));
>> - process_string_arg (((struct printf_spec *) NULL));
>> +#define PROCESS_ARG_INT() va_arg (ap, int)
>> +#define PROCESS_ARG_LONG_INT() va_arg (ap, long int)
>> +#define PROCESS_ARG_LONG_LONG_INT() va_arg (ap, long long int)
>> +#define PROCESS_ARG_POINTER() va_arg (ap, void *)
>> +#define PROCESS_ARG_STRING() va_arg (ap, const char *)
>> +#define PROCESS_ARG_UNSIGNED_INT() va_arg (ap, unsigned int)
>> +#define PROCESS_ARG_UNSIGNED_LONG_INT() va_arg (ap, unsigned long int)
>> +#define PROCESS_ARG_UNSIGNED_LONG_LONG_INT() va_arg (ap, unsigned long long int)
>> +#define PROCESS_ARG_WCHAR_T() va_arg (ap, wchar_t)
>> +#define PROCESS_ARG_WSTRING() va_arg (ap, const wchar_t *)
>
> I think it would be nicer to spell these macros in lower case.
Fair enough, I've renamed the macros to lower case before pushing.
Thanks,
Florian
@@ -650,8 +650,9 @@ static const uint8_t jump_table[] =
REF (form_unknown) /* for 'I' */ \
}
-
-#define process_arg(fspec) \
+/* Before invoking this macro, PROCESS_ARG_INT etc. macros have to be
+ defined to extract one argument of the appropriate type. */
+#define process_arg() \
/* Start real work. We know about all flags and modifiers and \
now process the wanted format specifier. */ \
LABEL (form_percent): \
@@ -665,13 +666,7 @@ static const uint8_t jump_table[] =
\
if (is_longlong) \
{ \
- long long int signed_number; \
- \
- if (fspec == NULL) \
- signed_number = va_arg (ap, long long int); \
- else \
- signed_number = args_value[fspec->data_arg].pa_long_long_int; \
- \
+ long long int signed_number = PROCESS_ARG_LONG_LONG_INT (); \
is_negative = signed_number < 0; \
number.longlong = is_negative ? (- signed_number) : signed_number; \
\
@@ -680,29 +675,14 @@ static const uint8_t jump_table[] =
else \
{ \
long int signed_number; \
- \
- if (fspec == NULL) \
- { \
- if (is_long_num) \
- signed_number = va_arg (ap, long int); \
- else if (is_char) \
- signed_number = (signed char) va_arg (ap, unsigned int); \
- else if (!is_short) \
- signed_number = va_arg (ap, int); \
- else \
- signed_number = (short int) va_arg (ap, unsigned int); \
- } \
+ if (is_long_num) \
+ signed_number = PROCESS_ARG_LONG_INT (); \
+ else if (is_char) \
+ signed_number = (signed char) PROCESS_ARG_UNSIGNED_INT (); \
+ else if (!is_short) \
+ signed_number = PROCESS_ARG_INT (); \
else \
- if (is_long_num) \
- signed_number = args_value[fspec->data_arg].pa_long_int; \
- else if (is_char) \
- signed_number = (signed char) \
- args_value[fspec->data_arg].pa_u_int; \
- else if (!is_short) \
- signed_number = args_value[fspec->data_arg].pa_int; \
- else \
- signed_number = (short int) \
- args_value[fspec->data_arg].pa_u_int; \
+ signed_number = (short int) PROCESS_ARG_UNSIGNED_INT (); \
\
is_negative = signed_number < 0; \
number.word = is_negative ? (- signed_number) : signed_number; \
@@ -737,10 +717,7 @@ static const uint8_t jump_table[] =
\
if (is_longlong) \
{ \
- if (fspec == NULL) \
- number.longlong = va_arg (ap, unsigned long long int); \
- else \
- number.longlong = args_value[fspec->data_arg].pa_u_long_long_int; \
+ number.longlong = PROCESS_ARG_UNSIGNED_LONG_LONG_INT (); \
\
LABEL (longlong_number): \
if (prec < 0) \
@@ -776,28 +753,14 @@ static const uint8_t jump_table[] =
} \
else \
{ \
- if (fspec == NULL) \
- { \
- if (is_long_num) \
- number.word = va_arg (ap, unsigned long int); \
- else if (is_char) \
- number.word = (unsigned char) va_arg (ap, unsigned int); \
- else if (!is_short) \
- number.word = va_arg (ap, unsigned int); \
- else \
- number.word = (unsigned short int) va_arg (ap, unsigned int); \
- } \
+ if (is_long_num) \
+ number.word = PROCESS_ARG_UNSIGNED_LONG_INT (); \
+ else if (is_char) \
+ number.word = (unsigned char) PROCESS_ARG_UNSIGNED_INT (); \
+ else if (!is_short) \
+ number.word = PROCESS_ARG_UNSIGNED_INT (); \
else \
- if (is_long_num) \
- number.word = args_value[fspec->data_arg].pa_u_long_int; \
- else if (is_char) \
- number.word = (unsigned char) \
- args_value[fspec->data_arg].pa_u_int; \
- else if (!is_short) \
- number.word = args_value[fspec->data_arg].pa_u_int; \
- else \
- number.word = (unsigned short int) \
- args_value[fspec->data_arg].pa_u_int; \
+ number.word = (unsigned short int) PROCESS_ARG_UNSIGNED_INT (); \
\
LABEL (number): \
if (prec < 0) \
@@ -917,11 +880,7 @@ static const uint8_t jump_table[] =
LABEL (form_pointer): \
/* Generic pointer. */ \
{ \
- const void *ptr; \
- if (fspec == NULL) \
- ptr = va_arg (ap, void *); \
- else \
- ptr = args_value[fspec->data_arg].pa_pointer; \
+ const void *ptr = PROCESS_ARG_POINTER (); \
if (ptr != NULL) \
{ \
/* If the pointer is not NULL, write it as a %#x spec. */ \
@@ -962,30 +921,17 @@ static const uint8_t jump_table[] =
__libc_fatal ("*** %n in writable segment detected ***\n"); \
} \
/* Answer the count of characters written. */ \
- if (fspec == NULL) \
- { \
- if (is_longlong) \
- *(long long int *) va_arg (ap, void *) = done; \
- else if (is_long_num) \
- *(long int *) va_arg (ap, void *) = done; \
- else if (is_char) \
- *(char *) va_arg (ap, void *) = done; \
- else if (!is_short) \
- *(int *) va_arg (ap, void *) = done; \
- else \
- *(short int *) va_arg (ap, void *) = done; \
- } \
+ void *ptrptr = PROCESS_ARG_POINTER (); \
+ if (is_longlong) \
+ *(long long int *) ptrptr = done; \
+ else if (is_long_num) \
+ *(long int *) ptrptr = done; \
+ else if (is_char) \
+ *(char *) ptrptr = done; \
+ else if (!is_short) \
+ *(int *) ptrptr = done; \
else \
- if (is_longlong) \
- *(long long int *) args_value[fspec->data_arg].pa_pointer = done; \
- else if (is_long_num) \
- *(long int *) args_value[fspec->data_arg].pa_pointer = done; \
- else if (is_char) \
- *(char *) args_value[fspec->data_arg].pa_pointer = done; \
- else if (!is_short) \
- *(int *) args_value[fspec->data_arg].pa_pointer = done; \
- else \
- *(short int *) args_value[fspec->data_arg].pa_pointer = done; \
+ *(short int *) ptrptr = done; \
break; \
\
LABEL (form_strerror): \
@@ -997,7 +943,7 @@ static const uint8_t jump_table[] =
goto LABEL (print_string)
#ifdef COMPILE_WPRINTF
-# define process_string_arg(fspec) \
+# define process_string_arg() \
LABEL (form_character): \
/* Character. */ \
if (is_long) \
@@ -1005,11 +951,7 @@ static const uint8_t jump_table[] =
--width; /* Account for the character itself. */ \
if (!left) \
PAD (L' '); \
- if (fspec == NULL) \
- outchar (__btowc ((unsigned char) va_arg (ap, int))); /* Promoted. */ \
- else \
- outchar (__btowc ((unsigned char) \
- args_value[fspec->data_arg].pa_int)); \
+ outchar (__btowc ((unsigned char) PROCESS_ARG_INT ())); /* Promoted. */ \
if (left) \
PAD (L' '); \
break; \
@@ -1020,10 +962,7 @@ static const uint8_t jump_table[] =
--width; \
if (!left) \
PAD (L' '); \
- if (fspec == NULL) \
- outchar (va_arg (ap, wchar_t)); \
- else \
- outchar (args_value[fspec->data_arg].pa_wchar); \
+ outchar (PROCESS_ARG_WCHAR_T ()); \
if (left) \
PAD (L' '); \
} \
@@ -1035,10 +974,7 @@ static const uint8_t jump_table[] =
\
/* The string argument could in fact be `char *' or `wchar_t *'. \
But this should not make a difference here. */ \
- if (fspec == NULL) \
- string = (CHAR_T *) va_arg (ap, const wchar_t *); \
- else \
- string = (CHAR_T *) args_value[fspec->data_arg].pa_wstring; \
+ string = (CHAR_T *) PROCESS_ARG_WSTRING (); \
\
/* Entry point for printing other strings. */ \
LABEL (print_string): \
@@ -1090,7 +1026,7 @@ static const uint8_t jump_table[] =
} \
break;
#else
-# define process_string_arg(fspec) \
+# define process_string_arg() \
LABEL (form_character): \
/* Character. */ \
if (is_long) \
@@ -1098,10 +1034,7 @@ static const uint8_t jump_table[] =
--width; /* Account for the character itself. */ \
if (!left) \
PAD (' '); \
- if (fspec == NULL) \
- outchar ((unsigned char) va_arg (ap, int)); /* Promoted. */ \
- else \
- outchar ((unsigned char) args_value[fspec->data_arg].pa_int); \
+ outchar ((unsigned char) PROCESS_ARG_INT ()); /* Promoted. */ \
if (left) \
PAD (' '); \
break; \
@@ -1114,9 +1047,7 @@ static const uint8_t jump_table[] =
size_t len; \
\
memset (&mbstate, '\0', sizeof (mbstate_t)); \
- len = __wcrtomb (buf, (fspec == NULL ? va_arg (ap, wchar_t) \
- : args_value[fspec->data_arg].pa_wchar), \
- &mbstate); \
+ len = __wcrtomb (buf, PROCESS_ARG_WCHAR_T (), &mbstate); \
if (len == (size_t) -1) \
{ \
/* Something went wrong during the conversion. Bail out. */ \
@@ -1138,10 +1069,7 @@ static const uint8_t jump_table[] =
\
/* The string argument could in fact be `char *' or `wchar_t *'. \
But this should not make a difference here. */ \
- if (fspec == NULL) \
- string = (char *) va_arg (ap, const char *); \
- else \
- string = (char *) args_value[fspec->data_arg].pa_string; \
+ string = (char *) PROCESS_ARG_STRING (); \
\
/* Entry point for printing other strings. */ \
LABEL (print_string): \
@@ -1322,7 +1250,6 @@ vfprintf (FILE *s, const CHAR_T *format, va_list ap, unsigned int mode_flags)
STEP0_3_TABLE;
STEP4_TABLE;
- union printf_arg *args_value; /* This is not used here but ... */
int is_negative; /* Flag for negative number. */
union
{
@@ -1337,7 +1264,9 @@ vfprintf (FILE *s, const CHAR_T *format, va_list ap, unsigned int mode_flags)
int left = 0; /* Left-justify output. */
int showsign = 0; /* Always begin with plus or minus sign. */
int group = 0; /* Print numbers according grouping rules. */
- int is_long_double = 0; /* Argument is long double/ long long int. */
+ /* Argument is long double/long long int. Only used if
+ double/long double or long int/long long int are distinct. */
+ int is_long_double __attribute__ ((unused)) = 0;
int is_short = 0; /* Argument is short int. */
int is_long = 0; /* Argument is long int. */
int is_char = 0; /* Argument is promoted (unsigned) char. */
@@ -1545,8 +1474,28 @@ vfprintf (FILE *s, const CHAR_T *format, va_list ap, unsigned int mode_flags)
/* Process current format. */
while (1)
{
- process_arg (((struct printf_spec *) NULL));
- process_string_arg (((struct printf_spec *) NULL));
+#define PROCESS_ARG_INT() va_arg (ap, int)
+#define PROCESS_ARG_LONG_INT() va_arg (ap, long int)
+#define PROCESS_ARG_LONG_LONG_INT() va_arg (ap, long long int)
+#define PROCESS_ARG_POINTER() va_arg (ap, void *)
+#define PROCESS_ARG_STRING() va_arg (ap, const char *)
+#define PROCESS_ARG_UNSIGNED_INT() va_arg (ap, unsigned int)
+#define PROCESS_ARG_UNSIGNED_LONG_INT() va_arg (ap, unsigned long int)
+#define PROCESS_ARG_UNSIGNED_LONG_LONG_INT() va_arg (ap, unsigned long long int)
+#define PROCESS_ARG_WCHAR_T() va_arg (ap, wchar_t)
+#define PROCESS_ARG_WSTRING() va_arg (ap, const wchar_t *)
+ process_arg ();
+ process_string_arg ();
+#undef PROCESS_ARG_INT
+#undef PROCESS_ARG_LONG_INT
+#undef PROCESS_ARG_LONG_LONG_INT
+#undef PROCESS_ARG_POINTER
+#undef PROCESS_ARG_STRING
+#undef PROCESS_ARG_UNSIGNED_INT
+#undef PROCESS_ARG_UNSIGNED_LONG_INT
+#undef PROCESS_ARG_UNSIGNED_LONG_LONG_INT
+#undef PROCESS_ARG_WCHAR_T
+#undef PROCESS_ARG_WSTRING
LABEL (form_float):
LABEL (form_floathex):
@@ -1850,7 +1799,8 @@ printf_positional (FILE *s, const CHAR_T *format, int readonly_format,
int left = specs[nspecs_done].info.left;
int showsign = specs[nspecs_done].info.showsign;
int group = specs[nspecs_done].info.group;
- int is_long_double = specs[nspecs_done].info.is_long_double;
+ int is_long_double __attribute__ ((unused))
+ = specs[nspecs_done].info.is_long_double;
int is_short = specs[nspecs_done].info.is_short;
int is_char = specs[nspecs_done].info.is_char;
int is_long = specs[nspecs_done].info.is_long;
@@ -1933,8 +1883,30 @@ printf_positional (FILE *s, const CHAR_T *format, int readonly_format,
JUMP (spec, step4_jumps);
- process_arg ((&specs[nspecs_done]));
- process_string_arg ((&specs[nspecs_done]));
+#define PROCESS_ARG_DATA args_value[specs[nspecs_done].data_arg]
+#define PROCESS_ARG_INT() PROCESS_ARG_DATA.pa_int
+#define PROCESS_ARG_LONG_INT() PROCESS_ARG_DATA.pa_long_int
+#define PROCESS_ARG_LONG_LONG_INT() PROCESS_ARG_DATA.pa_long_long_int
+#define PROCESS_ARG_POINTER() PROCESS_ARG_DATA.pa_pointer
+#define PROCESS_ARG_STRING() PROCESS_ARG_DATA.pa_string
+#define PROCESS_ARG_UNSIGNED_INT() PROCESS_ARG_DATA.pa_u_int
+#define PROCESS_ARG_UNSIGNED_LONG_INT() PROCESS_ARG_DATA.pa_u_long_int
+#define PROCESS_ARG_UNSIGNED_LONG_LONG_INT() PROCESS_ARG_DATA.pa_u_long_long_int
+#define PROCESS_ARG_WCHAR_T() PROCESS_ARG_DATA.pa_wchar
+#define PROCESS_ARG_WSTRING() PROCESS_ARG_DATA.pa_wstring
+ process_arg ();
+ process_string_arg ();
+#undef PROCESS_ARG_DATA
+#undef PROCESS_ARG_INT
+#undef PROCESS_ARG_LONG_INT
+#undef PROCESS_ARG_LONG_LONG_INT
+#undef PROCESS_ARG_POINTER
+#undef PROCESS_ARG_STRING
+#undef PROCESS_ARG_UNSIGNED_INT
+#undef PROCESS_ARG_UNSIGNED_LONG_INT
+#undef PROCESS_ARG_UNSIGNED_LONG_LONG_INT
+#undef PROCESS_ARG_WCHAR_T
+#undef PROCESS_ARG_WSTRING
LABEL (form_float):
LABEL (form_floathex):