c-common.c (format_wanted_type): Add reading_from_flag.

* c-common.c (format_wanted_type): Add reading_from_flag.
	(print_char_table): Mark %s and %S formats with flag "R".
	(check_format_info_main): Set up reading_from_flag appropriately.
	If aflag, always set writing_in_flag rather than relying on the
	format used being a scanf format and so having it set.
	(check_format_types): Check for formats reading through null
	pointers.

testsuite:
	* gcc.dg/c90-printf-1.c: Add test for printf formats reading
	through a null pointer.

From-SVN: r38104
This commit is contained in:
Joseph Myers 2000-12-07 07:40:45 +00:00 committed by Joseph Myers
parent 8308e0b786
commit 014e7f1d30
4 changed files with 54 additions and 15 deletions

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@ -1,3 +1,13 @@
2000-12-07 Joseph S. Myers <jsm28@cam.ac.uk>
* c-common.c (format_wanted_type): Add reading_from_flag.
(print_char_table): Mark %s and %S formats with flag "R".
(check_format_info_main): Set up reading_from_flag appropriately.
If aflag, always set writing_in_flag rather than relying on the
format used being a scanf format and so having it set.
(check_format_types): Check for formats reading through null
pointers.
2000-12-07 Joseph S. Myers <jsm28@cam.ac.uk>
* invoke.texi (-Wformat): Document what format features are

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@ -1416,6 +1416,7 @@ typedef struct
years in some locales, "4" for "2" which becomes "3" with an "E" modifier,
"o" if use of strftime "O" is a GNU extension beyond C99,
"W" if the argument is a pointer which is dereferenced and written into,
"R" if the argument is a pointer which is dereferenced and read from,
"i" for printf integer formats where the '0' flag is ignored with
precision, and "[" for the starting character of a scanf scanset. */
const char *flags2;
@ -1521,6 +1522,9 @@ typedef struct format_wanted_type
/* Whether the argument, dereferenced once, is written into and so the
argument must not be a pointer to a const-qualified type. */
int writing_in_flag;
/* Whether the argument, dereferenced once, is read from and so
must not be a NULL pointer. */
int reading_from_flag;
/* If warnings should be of the form "field precision is not type int",
the name to use (in this case "field precision"), otherwise NULL,
for "%s format, %s arg" type messages. If (in an extension), this
@ -1694,23 +1698,23 @@ static const format_flag_pair strftime_flag_pairs[] =
static const format_char_info print_char_table[] =
{
/* C89 conversion specifiers. */
{ "di", 0, STD_C89, { T89_I, T99_SC, T89_S, T89_L, T99_LL, TEX_LL, T99_SST, T99_PD, T99_IM }, "-wp0 +'I", "i" },
{ "oxX", 0, STD_C89, { T89_UI, T99_UC, T89_US, T89_UL, T99_ULL, TEX_ULL, T99_ST, T99_UPD, T99_UIM }, "-wp0#", "i" },
{ "u", 0, STD_C89, { T89_UI, T99_UC, T89_US, T89_UL, T99_ULL, TEX_ULL, T99_ST, T99_UPD, T99_UIM }, "-wp0'I", "i" },
{ "fgG", 0, STD_C89, { T89_D, BADLEN, BADLEN, T99_D, BADLEN, T89_LD, BADLEN, BADLEN, BADLEN }, "-wp0 +#'", "" },
{ "eE", 0, STD_C89, { T89_D, BADLEN, BADLEN, T99_D, BADLEN, T89_LD, BADLEN, BADLEN, BADLEN }, "-wp0 +#", "" },
{ "c", 0, STD_C89, { T89_I, BADLEN, BADLEN, T94_WI, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN }, "-w", "" },
{ "s", 1, STD_C89, { T89_C, BADLEN, BADLEN, T94_W, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN }, "-wp", "c" },
{ "p", 1, STD_C89, { T89_V, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN }, "-w", "c" },
{ "n", 1, STD_C89, { T89_I, T99_SC, T89_S, T89_L, T99_LL, BADLEN, T99_SST, T99_PD, T99_IM }, "", "W" },
{ "di", 0, STD_C89, { T89_I, T99_SC, T89_S, T89_L, T99_LL, TEX_LL, T99_SST, T99_PD, T99_IM }, "-wp0 +'I", "i" },
{ "oxX", 0, STD_C89, { T89_UI, T99_UC, T89_US, T89_UL, T99_ULL, TEX_ULL, T99_ST, T99_UPD, T99_UIM }, "-wp0#", "i" },
{ "u", 0, STD_C89, { T89_UI, T99_UC, T89_US, T89_UL, T99_ULL, TEX_ULL, T99_ST, T99_UPD, T99_UIM }, "-wp0'I", "i" },
{ "fgG", 0, STD_C89, { T89_D, BADLEN, BADLEN, T99_D, BADLEN, T89_LD, BADLEN, BADLEN, BADLEN }, "-wp0 +#'", "" },
{ "eE", 0, STD_C89, { T89_D, BADLEN, BADLEN, T99_D, BADLEN, T89_LD, BADLEN, BADLEN, BADLEN }, "-wp0 +#", "" },
{ "c", 0, STD_C89, { T89_I, BADLEN, BADLEN, T94_WI, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN }, "-w", "" },
{ "s", 1, STD_C89, { T89_C, BADLEN, BADLEN, T94_W, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN }, "-wp", "cR" },
{ "p", 1, STD_C89, { T89_V, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN }, "-w", "c" },
{ "n", 1, STD_C89, { T89_I, T99_SC, T89_S, T89_L, T99_LL, BADLEN, T99_SST, T99_PD, T99_IM }, "", "W" },
/* C99 conversion specifiers. */
{ "F", 0, STD_C99, { T99_D, BADLEN, BADLEN, T99_D, BADLEN, T99_LD, BADLEN, BADLEN, BADLEN }, "-wp0 +#'", "" },
{ "aA", 0, STD_C99, { T99_D, BADLEN, BADLEN, T99_D, BADLEN, T99_LD, BADLEN, BADLEN, BADLEN }, "-wp0 +#", "" },
{ "F", 0, STD_C99, { T99_D, BADLEN, BADLEN, T99_D, BADLEN, T99_LD, BADLEN, BADLEN, BADLEN }, "-wp0 +#'", "" },
{ "aA", 0, STD_C99, { T99_D, BADLEN, BADLEN, T99_D, BADLEN, T99_LD, BADLEN, BADLEN, BADLEN }, "-wp0 +#", "" },
/* X/Open conversion specifiers. */
{ "C", 0, STD_EXT, { TEX_WI, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN }, "-w", "" },
{ "S", 1, STD_EXT, { TEX_W, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN }, "-wp", "" },
{ "C", 0, STD_EXT, { TEX_WI, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN }, "-w", "" },
{ "S", 1, STD_EXT, { TEX_W, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN }, "-wp", "R" },
/* GNU conversion specifiers. */
{ "m", 0, STD_EXT, { T89_V, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN }, "-wp", "" },
{ "m", 0, STD_EXT, { T89_V, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN }, "-wp", "" },
{ NULL, 0, 0, NOLENGTHS, NULL, NULL }
};
@ -2718,6 +2722,7 @@ check_format_info_main (status, res, info, format_chars, format_length,
width_wanted_type.pointer_count = 0;
width_wanted_type.char_lenient_flag = 0;
width_wanted_type.writing_in_flag = 0;
width_wanted_type.reading_from_flag = 0;
width_wanted_type.name = _("field width");
width_wanted_type.param = cur_param;
width_wanted_type.arg_num = arg_num;
@ -2803,6 +2808,7 @@ check_format_info_main (status, res, info, format_chars, format_length,
precision_wanted_type.pointer_count = 0;
precision_wanted_type.char_lenient_flag = 0;
precision_wanted_type.writing_in_flag = 0;
precision_wanted_type.reading_from_flag = 0;
precision_wanted_type.name = _("field precision");
precision_wanted_type.param = cur_param;
precision_wanted_type.arg_num = arg_num;
@ -3129,8 +3135,16 @@ check_format_info_main (status, res, info, format_chars, format_length,
if (strchr (fci->flags2, 'c') != 0)
main_wanted_type.char_lenient_flag = 1;
main_wanted_type.writing_in_flag = 0;
if (strchr (fci->flags2, 'W') != 0)
main_wanted_type.reading_from_flag = 0;
if (aflag)
main_wanted_type.writing_in_flag = 1;
else
{
if (strchr (fci->flags2, 'W') != 0)
main_wanted_type.writing_in_flag = 1;
if (strchr (fci->flags2, 'R') != 0)
main_wanted_type.reading_from_flag = 1;
}
main_wanted_type.name = NULL;
main_wanted_type.param = cur_param;
main_wanted_type.arg_num = arg_num;
@ -3208,6 +3222,15 @@ check_format_types (status, types)
"writing through null pointer (arg %d)",
arg_num);
/* Check for reading through a NULL pointer. */
if (types->reading_from_flag
&& i == 0
&& cur_param != 0
&& integer_zerop (cur_param))
status_warning (status,
"reading through null pointer (arg %d)",
arg_num);
if (cur_param != 0 && TREE_CODE (cur_param) == ADDR_EXPR)
cur_param = TREE_OPERAND (cur_param, 0);
else

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@ -1,3 +1,8 @@
2000-12-07 Joseph S. Myers <jsm28@cam.ac.uk>
* gcc.dg/c90-printf-1.c: Add test for printf formats reading
through a null pointer.
2000-12-06 Kriang Lerdsuwanakij <lerdsuwa@users.sourceforge.net>
* g++.old-deja/g++.oliva/partspec1.C: Remove XFAIL.

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@ -245,4 +245,5 @@ foo (int i, int i1, int i2, unsigned int u, double d, char *s, void *p,
printf ("%n", cn); /* { dg-warning "constant" "%n with const" } */
printf ((const char *)L"foo"); /* { dg-warning "wide" "wide string" } */
printf ("%n", (int *)0); /* { dg-warning "null" "%n with NULL" } */
printf ("%s", (char *)0); /* { dg-warning "null" "%s with NULL" } */
}