gcc/builtins.h

   1 /* Expand builtin functions.
   2    Copyright (C) 1988-2020 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_BUILTINS_H
  21 #define GCC_BUILTINS_H
  22
  23 #include <mpc.h>
  24
  25 /* Target-dependent globals.  */
  26 struct target_builtins {
  27   /* For each register that may be used for calling a function, this
  28      gives a mode used to copy the register's value.  VOIDmode indicates
  29      the register is not used for calling a function.  If the machine
  30      has register windows, this gives only the outbound registers.
  31      INCOMING_REGNO gives the corresponding inbound register.  */
  32   fixed_size_mode_pod x_apply_args_mode[FIRST_PSEUDO_REGISTER];
  33
  34   /* For each register that may be used for returning values, this gives
  35      a mode used to copy the register's value.  VOIDmode indicates the
  36      register is not used for returning values.  If the machine has
  37      register windows, this gives only the outbound registers.
  38      INCOMING_REGNO gives the corresponding inbound register.  */
  39   fixed_size_mode_pod x_apply_result_mode[FIRST_PSEUDO_REGISTER];
  40 };
  41
  42 extern struct target_builtins default_target_builtins;
  43 #if SWITCHABLE_TARGET
  44 extern struct target_builtins *this_target_builtins;
  45 #else
  46 #define this_target_builtins (&default_target_builtins)
  47 #endif
  48
  49 /* Non-zero if __builtin_constant_p should be folded right away.  */
  50 extern bool force_folding_builtin_constant_p;
  51
  52 extern bool called_as_built_in (tree);
  53 extern bool get_object_alignment_1 (tree, unsigned int *,
  54                                     unsigned HOST_WIDE_INT *);
  55 extern unsigned int get_object_alignment (tree);
  56 extern bool get_pointer_alignment_1 (tree, unsigned int *,
  57                                      unsigned HOST_WIDE_INT *);
  58 extern unsigned int get_pointer_alignment (tree);
  59 extern unsigned string_length (const void*, unsigned, unsigned);
  60
  61 struct c_strlen_data
  62 {
  63   /* [MINLEN, MAXBOUND, MAXLEN] is a range describing the length of
  64      one or more strings of possibly unknown length.  For a single
  65      string of known length the range is a constant where
  66      MINLEN == MAXBOUND == MAXLEN holds.
  67      For other strings, MINLEN is the length of the shortest known
  68      string.  MAXBOUND is the length of a string that could be stored
  69      in the largest array referenced by the expression.  MAXLEN is
  70      the length of the longest sequence of non-zero bytes
  71      in an object referenced by the expression.  For such strings,
  72      MINLEN <= MAXBOUND <= MAXLEN holds.  For example, given:
  73        struct A { char a[7], b[]; };
  74        extern struct A *p;
  75        n = strlen (p->a);
  76      the computed range will be [0, 6, ALL_ONES].
  77      However, for a conditional expression involving a string
  78      of known length and an array of unknown bound such as
  79        n = strlen (i ? p->b : "123");
  80      the range will be [3, 3, ALL_ONES].
  81      MINLEN != 0 && MAXLEN == ALL_ONES indicates that MINLEN is
  82      the length of the shortest known string and implies that
  83      the shortest possible string referenced by the expression may
  84      actually be the empty string.  This distinction is useful for
  85      diagnostics.  get_range_strlen() return value distinguishes
  86      between these two cases.
  87      As the tighter (and more optimistic) bound, MAXBOUND is suitable
  88      for diagnostics but not for optimization.
  89      As the more conservative bound, MAXLEN is intended to be used
  90      for optimization.  */
  91   tree minlen;
  92   tree maxlen;
  93   tree maxbound;
  94   /* When non-null, DECL refers to the declaration known to store
  95      an unterminated constant character array, as in:
  96      const char s[] = { 'a', 'b', 'c' };
  97      It is used to diagnose uses of such arrays in functions such as
  98      strlen() that expect a nul-terminated string as an argument.  */
  99   tree decl;
 100   /* Non-constant offset from the beginning of a string not accounted
 101      for in the length range.  Used to improve diagnostics.  */
 102   tree off;
 103 };
 104
 105 extern tree c_strlen (tree, int, c_strlen_data * = NULL, unsigned = 1);
 106 extern rtx c_readstr (const char *, scalar_int_mode, bool = true);
 107 extern void expand_builtin_setjmp_setup (rtx, rtx);
 108 extern void expand_builtin_setjmp_receiver (rtx);
 109 extern void expand_builtin_update_setjmp_buf (rtx);
 110 extern tree mathfn_built_in (tree, enum built_in_function fn);
 111 extern tree mathfn_built_in (tree, combined_fn);
 112 extern tree mathfn_built_in_type (combined_fn);
 113 extern rtx builtin_strncpy_read_str (void *, HOST_WIDE_INT, scalar_int_mode);
 114 extern rtx builtin_memset_read_str (void *, HOST_WIDE_INT, scalar_int_mode);
 115 extern rtx expand_builtin_saveregs (void);
 116 extern tree std_build_builtin_va_list (void);
 117 extern tree std_fn_abi_va_list (tree);
 118 extern tree std_canonical_va_list_type (tree);
 119 extern void std_expand_builtin_va_start (tree, rtx);
 120 extern void expand_builtin_trap (void);
 121 extern void expand_ifn_atomic_bit_test_and (gcall *);
 122 extern void expand_ifn_atomic_compare_exchange (gcall *);
 123 extern rtx expand_builtin (tree, rtx, rtx, machine_mode, int);
 124 extern enum built_in_function builtin_mathfn_code (const_tree);
 125 extern tree fold_builtin_expect (location_t, tree, tree, tree, tree);
 126 extern bool avoid_folding_inline_builtin (tree);
 127 extern tree fold_call_expr (location_t, tree, bool);
 128 extern tree fold_builtin_call_array (location_t, tree, tree, int, tree *);
 129 extern bool validate_gimple_arglist (const gcall *, ...);
 130 extern rtx default_expand_builtin (tree, rtx, rtx, machine_mode, int);
 131 extern bool fold_builtin_next_arg (tree, bool);
 132 extern tree do_mpc_arg2 (tree, tree, tree, int, int (*)(mpc_ptr, mpc_srcptr, mpc_srcptr, mpc_rnd_t));
 133 extern tree fold_call_stmt (gcall *, bool);
 134 extern void set_builtin_user_assembler_name (tree decl, const char *asmspec);
 135 extern bool is_simple_builtin (tree);
 136 extern bool is_inexpensive_builtin (tree);
 137 extern bool readonly_data_expr (tree exp);
 138 extern bool init_target_chars (void);
 139 extern unsigned HOST_WIDE_INT target_newline;
 140 extern unsigned HOST_WIDE_INT target_percent;
 141 extern char target_percent_s[3];
 142 extern char target_percent_c[3];
 143 extern char target_percent_s_newline[4];
 144 extern bool target_char_cst_p (tree t, char *p);
 145
 146 extern internal_fn associated_internal_fn (tree);
 147 extern internal_fn replacement_internal_fn (gcall *);
 148
 149 extern bool check_nul_terminated_array (tree, tree, tree = NULL_TREE);
 150 extern void warn_string_no_nul (location_t, tree, const char *, tree,
 151                                 tree, tree = NULL_TREE, bool = false,
 152                                 const wide_int[2] = NULL);
 153 extern tree unterminated_array (tree, tree * = NULL, bool * = NULL);
 154 extern bool builtin_with_linkage_p (tree);
 155
 156 /* Describes a reference to an object used in an access.  */
 157 struct access_ref
 158 {
 159   /* Set the bounds of the reference to at most as many bytes
 160      as the first argument or unknown when null, and at least
 161      one when the second argument is true unless the first one
 162      is a constant zero.  */
 163   access_ref (tree = NULL_TREE, bool = false);
 164
 165   /* Reference to the accessed object(s).  */
 166   tree ref;
 167
 168   /* Range of byte offsets into and sizes of the object(s).  */
 169   offset_int offrng[2];
 170   offset_int sizrng[2];
 171   /* Range of the bound of the access: denotes that the access
 172      is at least BNDRNG[0] bytes but no more than BNDRNG[1].
 173      For string functions the size of the actual access is
 174      further constrained by the length of the string.  */
 175   offset_int bndrng[2];
 176
 177   /* Return true if OFFRNG is the constant zero.  */
 178   bool offset_zero () const
 179   {
 180     return offrng[0] == 0 && offrng[1] == 0;
 181   }
 182
 183   /* Return true if OFFRNG is bounded to a subrange of offset values
 184      valid for the largest possible object.  */
 185   bool offset_bounded () const;
 186
 187   /* Return the maximum amount of space remaining and if non-null, set
 188      argument to the minimum.  */
 189   offset_int size_remaining (offset_int * = NULL) const;
 190
 191   /* Set the size range to the maximum.  */
 192   void set_max_size_range ()
 193   {
 194     sizrng[0] = 0;
 195     sizrng[1] = wi::to_offset (max_object_size ());
 196   }
 197
 198   /* Add OFF to the offset range.  */
 199   void add_offset (const offset_int &off)
 200   {
 201     add_offset (off, off);
 202   }
 203
 204   /* Add the range [MIN, MAX] to the offset range.  */
 205   void add_offset (const offset_int &, const offset_int &);
 206
 207   /* Add the maximum representable offset to the offset range.  */
 208   void add_max_offset ()
 209   {
 210     offset_int maxoff = wi::to_offset (TYPE_MAX_VALUE (ptrdiff_type_node));
 211     add_offset (-maxoff - 1, maxoff);
 212   }
 213
 214   /* Used to fold integer expressions when called from front ends.  */
 215   tree (*eval)(tree);
 216   /* Set if trailing one-element arrays should be treated as flexible
 217      array members.  */
 218   bool trail1special;
 219   /* Set if valid offsets must start at zero (for declared and allocated
 220      objects but not for others referenced by pointers).  */
 221   bool base0;
 222 };
 223
 224 /* Describes a pair of references used in an access by built-in
 225    functions like memcpy.  */
 226 struct access_data
 227 {
 228   /* Set the access to at most MAXWRITE and MAXREAD bytes, and
 229      at least 1 when MINWRITE or MINREAD, respectively, is set.  */
 230   access_data (tree expr, access_mode mode,
 231                tree maxwrite = NULL_TREE, bool minwrite = false,
 232                tree maxread = NULL_TREE, bool minread = false)
 233     : call (expr),
 234       dst (maxwrite, minwrite), src (maxread, minread), mode (mode) { }
 235
 236   /* Built-in function call.  */
 237   tree call;
 238   /* Destination and source of the access.  */
 239   access_ref dst, src;
 240   /* Read-only for functions like memcmp or strlen, write-only
 241      for memset, read-write for memcpy or strcat.  */
 242   access_mode mode;
 243 };
 244
 245 class range_query;
 246 extern tree gimple_call_alloc_size (gimple *, wide_int[2] = NULL,
 247                                     range_query * = NULL);
 248 extern tree gimple_parm_array_size (tree, wide_int[2], range_query * = NULL);
 249 extern tree compute_objsize (tree, int, access_ref *, range_query * = NULL);
 250 extern tree compute_objsize (tree, int, tree * = NULL, tree * = NULL,
 251                              range_query * = NULL);
 252 extern bool check_access (tree, tree, tree, tree, tree,
 253                           access_mode, const access_data * = NULL);
 254
 255 #endif /* GCC_BUILTINS_H */