gcc/c-family/c-format.h

   1 /* Check calls to formatted I/O functions (-Wformat).
   2    Copyright (C) 1992-2020 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 3, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 #ifndef GCC_C_FORMAT_H
  21 #define GCC_C_FORMAT_H
  22
  23 /* The meaningfully distinct length modifiers for format checking recognized
  24    by GCC.  */
  25 enum format_lengths
  26 {
  27   FMT_LEN_none,
  28   FMT_LEN_hh,
  29   FMT_LEN_h,
  30   FMT_LEN_l,
  31   FMT_LEN_ll,
  32   FMT_LEN_L,
  33   FMT_LEN_z,
  34   FMT_LEN_t,
  35   FMT_LEN_j,
  36   FMT_LEN_H,
  37   FMT_LEN_D,
  38   FMT_LEN_DD,
  39   FMT_LEN_w,   /* GCC's HOST_WIDE_INT.  */
  40   FMT_LEN_MAX
  41 };
  42
  43
  44 /* The standard versions in which various format features appeared.  */
  45 enum format_std_version
  46 {
  47   STD_C89,
  48   STD_C94,
  49   STD_C9L, /* C99, but treat as C89 if -Wno-long-long.  */
  50   STD_C99,
  51   STD_C2X,
  52   STD_EXT
  53 };
  54
  55 /* Flags that may apply to a particular kind of format checked by GCC.  */
  56 enum
  57 {
  58   /* This format converts arguments of types determined by the
  59      format string.  */
  60   FMT_FLAG_ARG_CONVERT = 1,
  61   /* The scanf allocation 'a' kludge applies to this format kind.  */
  62   FMT_FLAG_SCANF_A_KLUDGE = 2,
  63   /* A % during parsing a specifier is allowed to be a modified % rather
  64      that indicating the format is broken and we are out-of-sync.  */
  65   FMT_FLAG_FANCY_PERCENT_OK = 4,
  66   /* With $ operand numbers, it is OK to reference the same argument more
  67      than once.  */
  68   FMT_FLAG_DOLLAR_MULTIPLE = 8,
  69   /* This format type uses $ operand numbers (strfmon doesn't).  */
  70   FMT_FLAG_USE_DOLLAR = 16,
  71   /* Zero width is bad in this type of format (scanf).  */
  72   FMT_FLAG_ZERO_WIDTH_BAD = 32,
  73   /* Empty precision specification is OK in this type of format (printf).  */
  74   FMT_FLAG_EMPTY_PREC_OK = 64,
  75   /* Gaps are allowed in the arguments with $ operand numbers if all
  76      arguments are pointers (scanf).  */
  77   FMT_FLAG_DOLLAR_GAP_POINTER_OK = 128,
  78   /* The format arg is an opaque object that will be parsed by an external
  79      facility.  */
  80   FMT_FLAG_PARSE_ARG_CONVERT_EXTERNAL = 256
  81   /* Not included here: details of whether width or precision may occur
  82      (controlled by width_char and precision_char); details of whether
  83      '*' can be used for these (width_type and precision_type); details
  84      of whether length modifiers can occur (length_char_specs).  */
  85 };
  86
  87 /* Structure describing a length modifier supported in format checking, and
  88    possibly a doubled version such as "hh".  */
  89 struct format_length_info
  90 {
  91   /* Name of the single-character length modifier. If prefixed by
  92      a zero character, it describes a multi character length
  93      modifier, like I64, I32, etc.  */
  94   const char *name;
  95   /* Index into a format_char_info.types array.  */
  96   enum format_lengths index;
  97   /* Standard version this length appears in.  */
  98   enum format_std_version std;
  99   /* Same, if the modifier can be repeated, or NULL if it can't.  */
 100   const char *double_name;
 101   enum format_lengths double_index;
 102   enum format_std_version double_std;
 103
 104   /* If this flag is set, just scalar width identity is checked, and
 105      not the type identity itself.  */
 106   int scalar_identity_flag;
 107 };
 108
 109
 110 /* Structure describing the combination of a conversion specifier
 111    (or a set of specifiers which act identically) and a length modifier.  */
 112 struct format_type_detail
 113 {
 114   /* The standard version this combination of length and type appeared in.
 115      This is only relevant if greater than those for length and type
 116      individually; otherwise it is ignored.  */
 117   enum format_std_version std;
 118   /* The name to use for the type, if different from that generated internally
 119      (e.g., "signed size_t").  */
 120   const char *name;
 121   /* The type itself.  */
 122   tree *type;
 123 };
 124
 125
 126 /* Macros to fill out tables of these.  */
 127 #define NOARGUMENTS     { T89_V, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN }
 128 #define BADLEN  { STD_C89, NULL, NULL }
 129 #define NOLENGTHS       { BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN }
 130
 131
 132 /* Structure describing a format conversion specifier (or a set of specifiers
 133    which act identically), and the length modifiers used with it.  */
 134 struct format_char_info
 135 {
 136   const char *format_chars;
 137   int pointer_count;
 138   enum format_std_version std;
 139   /* Types accepted for each length modifier.  */
 140   format_type_detail types[FMT_LEN_MAX];
 141   /* List of other modifier characters allowed with these specifiers.
 142      This lists flags, and additionally "w" for width, "p" for precision
 143      (right precision, for strfmon), "#" for left precision (strfmon),
 144      "a" for scanf "a" allocation extension (not applicable in C99 mode),
 145      "*" for scanf suppression, and "E" and "O" for those strftime
 146      modifiers.  */
 147   const char *flag_chars;
 148   /* List of additional flags describing these conversion specifiers.
 149      "c" for generic character pointers being allowed, "2" for strftime
 150      two digit year formats, "3" for strftime formats giving two digit
 151      years in some locales, "4" for "2" which becomes "3" with an "E" modifier,
 152      "o" if use of strftime "O" is a GNU extension beyond C99,
 153      "p" if use of strftime "O" is a C2x feature,
 154      "W" if the argument is a pointer which is dereferenced and written into,
 155      "R" if the argument is a pointer which is dereferenced and read from,
 156      "i" for printf integer formats where the '0' flag is ignored with
 157      precision, and "[" for the starting character of a scanf scanset,
 158      "<" if the specifier introduces a quoted sequence (such as "%<"),
 159      ">" if the specifier terminates a quoted sequence (such as "%>"),
 160      "[" if the specifier introduces a color sequence (such as "%r"),
 161      "]" if the specifier terminates a color sequence (such as "%R"),
 162      "'" (single quote) if the specifier is expected to be quoted when
 163      it appears outside a quoted sequence and unquoted otherwise (such
 164      as the GCC internal printf format directive "%T"), and
 165      "\"" (double quote) if the specifier is not expected to appear in
 166      a quoted sequence (such as the GCC internal format directive "%K".  */
 167   const char *flags2;
 168   /* If this format conversion character consumes more than one argument,
 169      CHAIN points to information about the next argument.  For later
 170      arguments, only POINTER_COUNT, TYPES, and the "c", "R", and "W" flags
 171      in FLAGS2 are used.  */
 172   const struct format_char_info *chain;
 173 };
 174
 175
 176 /* Structure describing a flag accepted by some kind of format.  */
 177 struct format_flag_spec
 178 {
 179   /* The flag character in question (0 for end of array).  */
 180   int flag_char;
 181   /* Zero if this entry describes the flag character in general, or a
 182      nonzero character that may be found in flags2 if it describes the
 183      flag when used with certain formats only.  If the latter, only
 184      the first such entry found that applies to the current conversion
 185      specifier is used; the values of 'name' and 'long_name' it supplies
 186      will be used, if non-NULL and the standard version is higher than
 187      the unpredicated one, for any pedantic warning.  For example, 'o'
 188      for strftime formats (meaning 'O' is an extension over C99).  */
 189   int predicate;
 190   /* Nonzero if the next character after this flag in the format should
 191      be skipped ('=' in strfmon), zero otherwise.  */
 192   int skip_next_char;
 193   /* True if the flag introduces quoting (as in GCC's %qE).  */
 194   bool quoting;
 195   /* The name to use for this flag in diagnostic messages.  For example,
 196      N_("'0' flag"), N_("field width").  */
 197   const char *name;
 198   /* Long name for this flag in diagnostic messages; currently only used for
 199      "ISO C does not support ...".  For example, N_("the 'I' printf flag").  */
 200   const char *long_name;
 201   /* The standard version in which it appeared.  */
 202   enum format_std_version std;
 203 };
 204
 205
 206 /* Structure describing a combination of flags that is bad for some kind
 207    of format.  */
 208 struct format_flag_pair
 209 {
 210   /* The first flag character in question (0 for end of array).  */
 211   int flag_char1;
 212   /* The second flag character.  */
 213   int flag_char2;
 214   /* Nonzero if the message should say that the first flag is ignored with
 215      the second, zero if the combination should simply be objected to.  */
 216   int ignored;
 217   /* Zero if this entry applies whenever this flag combination occurs,
 218      a nonzero character from flags2 if it only applies in some
 219      circumstances (e.g. 'i' for printf formats ignoring 0 with precision).  */
 220   int predicate;
 221 };
 222
 223
 224 /* Structure describing a particular kind of format processed by GCC.  */
 225 struct format_kind_info
 226 {
 227   /* The name of this kind of format, for use in diagnostics.  Also
 228      the name of the attribute (without preceding and following __).  */
 229   const char *name;
 230   /* Specifications of the length modifiers accepted; possibly NULL.  */
 231   const format_length_info *length_char_specs;
 232   /* Details of the conversion specification characters accepted.  */
 233   const format_char_info *conversion_specs;
 234   /* String listing the flag characters that are accepted.  */
 235   const char *flag_chars;
 236   /* String listing modifier characters (strftime) accepted.  May be NULL.  */
 237   const char *modifier_chars;
 238   /* Details of the flag characters, including pseudo-flags.  */
 239   const format_flag_spec *flag_specs;
 240   /* Details of bad combinations of flags.  */
 241   const format_flag_pair *bad_flag_pairs;
 242   /* Flags applicable to this kind of format.  */
 243   int flags;
 244   /* Flag character to treat a width as, or 0 if width not used.  */
 245   int width_char;
 246   /* Flag character to treat a left precision (strfmon) as,
 247      or 0 if left precision not used.  */
 248   int left_precision_char;
 249   /* Flag character to treat a precision (for strfmon, right precision) as,
 250      or 0 if precision not used.  */
 251   int precision_char;
 252   /* If a flag character has the effect of suppressing the conversion of
 253      an argument ('*' in scanf), that flag character, otherwise 0.  */
 254   int suppression_char;
 255   /* Flag character to treat a length modifier as (ignored if length
 256      modifiers not used).  Need not be placed in flag_chars for conversion
 257      specifiers, but is used to check for bad combinations such as length
 258      modifier with assignment suppression in scanf.  */
 259   int length_code_char;
 260   /* Assignment-allocation flag character ('m' in scanf), otherwise 0.  */
 261   int alloc_char;
 262   /* Pointer to type of argument expected if '*' is used for a width,
 263      or NULL if '*' not used for widths.  */
 264   tree *width_type;
 265   /* Pointer to type of argument expected if '*' is used for a precision,
 266      or NULL if '*' not used for precisions.  */
 267   tree *precision_type;
 268 };
 269
 270 #define T_I     &integer_type_node
 271 #define T89_I   { STD_C89, NULL, T_I }
 272 #define T_L     &long_integer_type_node
 273 #define T89_L   { STD_C89, NULL, T_L }
 274 #define T_LL    &long_long_integer_type_node
 275 #define T9L_LL  { STD_C9L, NULL, T_LL }
 276 #define TEX_LL  { STD_EXT, NULL, T_LL }
 277 #define T_S     &short_integer_type_node
 278 #define T89_S   { STD_C89, NULL, T_S }
 279 #define T_UI    &unsigned_type_node
 280 #define T89_UI  { STD_C89, NULL, T_UI }
 281 #define T_UL    &long_unsigned_type_node
 282 #define T89_UL  { STD_C89, NULL, T_UL }
 283 #define T_ULL   &long_long_unsigned_type_node
 284 #define T9L_ULL { STD_C9L, NULL, T_ULL }
 285 #define TEX_ULL { STD_EXT, NULL, T_ULL }
 286 #define T_US    &short_unsigned_type_node
 287 #define T89_US  { STD_C89, NULL, T_US }
 288 #define T_F     &float_type_node
 289 #define T89_F   { STD_C89, NULL, T_F }
 290 #define T99_F   { STD_C99, NULL, T_F }
 291 #define T_D     &double_type_node
 292 #define T89_D   { STD_C89, NULL, T_D }
 293 #define T99_D   { STD_C99, NULL, T_D }
 294 #define T_LD    &long_double_type_node
 295 #define T89_LD  { STD_C89, NULL, T_LD }
 296 #define T99_LD  { STD_C99, NULL, T_LD }
 297 #define T_C     &char_type_node
 298 #define T89_C   { STD_C89, NULL, T_C }
 299 #define T_SC    &signed_char_type_node
 300 #define T99_SC  { STD_C99, NULL, T_SC }
 301 #define T_UC    &unsigned_char_type_node
 302 #define T99_UC  { STD_C99, NULL, T_UC }
 303 #define T_V     &void_type_node
 304 #define T89_G   { STD_C89, NULL, &local_gimple_ptr_node }
 305 #define T_CGRAPH_NODE   { STD_C89, NULL, &local_cgraph_node_ptr_node }
 306 #define T89_T   { STD_C89, NULL, &local_tree_type_node }
 307 #define T89_V   { STD_C89, NULL, T_V }
 308 #define T_W     &wchar_type_node
 309 #define T94_W   { STD_C94, "wchar_t", T_W }
 310 #define TEX_W   { STD_EXT, "wchar_t", T_W }
 311 #define T_WI    &wint_type_node
 312 #define T94_WI  { STD_C94, "wint_t", T_WI }
 313 #define TEX_WI  { STD_EXT, "wint_t", T_WI }
 314 #define T_ST    &size_type_node
 315 #define T99_ST  { STD_C99, "size_t", T_ST }
 316 #define T_SST   &signed_size_type_node
 317 #define T99_SST { STD_C99, "signed size_t", T_SST }
 318 #define T_PD    &ptrdiff_type_node
 319 #define T99_PD  { STD_C99, "ptrdiff_t", T_PD }
 320 #define T_UPD   &unsigned_ptrdiff_type_node
 321 #define T99_UPD { STD_C99, "unsigned ptrdiff_t", T_UPD }
 322 #define T_IM    &intmax_type_node
 323 #define T99_IM  { STD_C99, "intmax_t", T_IM }
 324 #define T_UIM   &uintmax_type_node
 325 #define T99_UIM { STD_C99, "uintmax_t", T_UIM }
 326 #define T_D32   &dfloat32_type_node
 327 #define TEX_D32 { STD_EXT, "_Decimal32", T_D32 }
 328 #define T_D64   &dfloat64_type_node
 329 #define TEX_D64 { STD_EXT, "_Decimal64", T_D64 }
 330 #define T_D128  &dfloat128_type_node
 331 #define TEX_D128 { STD_EXT, "_Decimal128", T_D128 }
 332
 333 /* Structure describing how format attributes such as "printf" are
 334    interpreted as "gnu_printf" or "ms_printf" on a particular system.
 335    TARGET_OVERRIDES_FORMAT_ATTRIBUTES is used to specify target-specific
 336    defaults.  */
 337 struct target_ovr_attr
 338 {
 339   /* The name of the to be copied format attribute. */
 340   const char *named_attr_src;
 341   /* The name of the to be overridden format attribute. */
 342   const char *named_attr_dst;
 343 };
 344
 345 #endif /* GCC_C_FORMAT_H */