gcc/genconditions.cc

   1 /* Process machine description and calculate constant conditions.
   2    Copyright (C) 2001-2023 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
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3, or (at your option)
   9    any later version.
  10
  11    GCC is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License 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 /* In a machine description, all of the insn patterns - define_insn,
  21    define_expand, define_split, define_peephole, define_peephole2 -
  22    contain an optional C expression which makes the final decision
  23    about whether or not this pattern is usable.  That expression may
  24    turn out to be always false when the compiler is built.  If it is,
  25    most of the programs that generate code from the machine
  26    description can simply ignore the entire pattern.  */
  27
  28 #include "bconfig.h"
  29 #include "system.h"
  30 #include "coretypes.h"
  31 #include "tm.h"
  32 #include "rtl.h"
  33 #include "errors.h"
  34 #include "read-md.h"
  35 #include "gensupport.h"
  36
  37 /* so we can include except.h in the generated file.  */
  38 static int saw_eh_return;
  39
  40 static void write_header        (void);
  41 static void write_conditions    (void);
  42 static int write_one_condition  (void **, void *);
  43
  44 /* Generate the header for insn-conditions.c.  */
  45
  46 static void
  47 write_header (void)
  48 {
  49   puts ("\
  50 /* Generated automatically by the program `genconditions' from the target\n\
  51    machine description file.  */\n\
  52 \n\
  53 #define IN_TARGET_CODE 1\n\
  54 #include \"bconfig.h\"\n\
  55 #define INCLUDE_STRING\n\
  56 #include \"system.h\"\n\
  57 \n\
  58 /* It is necessary, but not entirely safe, to include the headers below\n\
  59    in a generator program.  As a defensive measure, don't do so when the\n\
  60    table isn't going to have anything in it.  */\n\
  61 #if GCC_VERSION >= 3001\n\
  62 \n\
  63 /* Do not allow checking to confuse the issue.  */\n\
  64 #undef CHECKING_P\n\
  65 #define CHECKING_P 0\n\
  66 #undef ENABLE_TREE_CHECKING\n\
  67 #undef ENABLE_RTL_CHECKING\n\
  68 #undef ENABLE_RTL_FLAG_CHECKING\n\
  69 #undef ENABLE_GC_CHECKING\n\
  70 #undef ENABLE_GC_ALWAYS_COLLECT\n\
  71 #define USE_ENUM_MODES\n\
  72 \n\
  73 #include \"coretypes.h\"\n\
  74 #include \"tm.h\"\n\
  75 #include \"insn-constants.h\"\n\
  76 #include \"rtl.h\"\n\
  77 #include \"memmodel.h\"\n\
  78 #include \"tm_p.h\"\n\
  79 #include \"hard-reg-set.h\"\n\
  80 #include \"function.h\"\n\
  81 #include \"emit-rtl.h\"\n\
  82 \n\
  83 /* Fake - insn-config.h doesn't exist yet.  */\n\
  84 #define MAX_RECOG_OPERANDS 10\n\
  85 #define MAX_DUP_OPERANDS 10\n\
  86 #define MAX_INSNS_PER_SPLIT 5\n\
  87 \n\
  88 #include \"regs.h\"\n\
  89 #include \"recog.h\"\n\
  90 #include \"output.h\"\n\
  91 #include \"flags.h\"\n\
  92 #include \"hard-reg-set.h\"\n\
  93 #include \"predict.h\"\n\
  94 #include \"basic-block.h\"\n\
  95 #include \"bitmap.h\"\n\
  96 #include \"df.h\"\n\
  97 #include \"resource.h\"\n\
  98 #include \"diagnostic-core.h\"\n\
  99 #include \"reload.h\"\n\
 100 #include \"tm-constrs.h\"\n");
 101
 102   if (saw_eh_return)
 103     puts ("#define HAVE_eh_return 1");
 104   puts ("#include \"except.h\"\n");
 105
 106   puts ("\
 107 /* Dummy external declarations.  */\n\
 108 extern rtx_insn *insn;\n\
 109 extern rtx ins1;\n\
 110 extern rtx operands[];\n\
 111 \n\
 112 #endif /* gcc >= 3.0.1 */\n");
 113 }
 114
 115 /* Write out one entry in the conditions table, using the data pointed
 116    to by SLOT.  Each entry looks like this:
 117
 118    { "! optimize_size && ! TARGET_READ_MODIFY_WRITE",
 119      __builtin_constant_p (! optimize_size && ! TARGET_READ_MODIFY_WRITE)
 120      ? (int) (! optimize_size && ! TARGET_READ_MODIFY_WRITE)
 121      : -1) },  */
 122
 123 static int
 124 write_one_condition (void **slot, void * ARG_UNUSED (dummy))
 125 {
 126   const struct c_test *test = *(const struct c_test *const *) slot;
 127   const char *p;
 128
 129   rtx_reader_ptr->print_md_ptr_loc (test->expr);
 130   fputs ("  { \"", stdout);
 131   for (p = test->expr; *p; p++)
 132     {
 133       switch (*p)
 134         {
 135         case '\n': fputs ("\\n\\", stdout); break;
 136         case '\\':
 137         case '\"': putchar ('\\'); break;
 138         default: break;
 139         }
 140       putchar (*p);
 141     }
 142
 143   fputs ("\",\n    __builtin_constant_p ", stdout);
 144   rtx_reader_ptr->print_c_condition (test->expr);
 145   fputs ("\n    ? (int) ", stdout);
 146   rtx_reader_ptr->print_c_condition (test->expr);
 147   fputs ("\n    : -1 },\n", stdout);
 148   return 1;
 149 }
 150
 151 /* Write out the complete conditions table, its size, and a flag
 152    indicating that gensupport.cc can now do insn elision.  */
 153 static void
 154 write_conditions (void)
 155 {
 156   puts ("\
 157 /* Structure definition duplicated from gensupport.h rather than\n\
 158    drag in that file and its dependencies.  */\n\
 159 struct c_test\n\
 160 {\n\
 161   const char *expr;\n\
 162   int value;\n\
 163 };\n\
 164 \n\
 165 /* This table lists each condition found in the machine description.\n\
 166    Each condition is mapped to its truth value (0 or 1), or -1 if that\n\
 167    cannot be calculated at compile time.\n\
 168    If we don't have __builtin_constant_p, or it's not acceptable in array\n\
 169    initializers, fall back to assuming that all conditions potentially\n\
 170    vary at run time.  It works in 3.0.1 and later; 3.0 only when not\n\
 171    optimizing.  */\n\
 172 \n\
 173 #if GCC_VERSION >= 3001\n\
 174 static const struct c_test insn_conditions[] = {\n");
 175
 176   traverse_c_tests (write_one_condition, 0);
 177
 178   puts ("  { nullptr, -1 }\n};\n#endif /* gcc >= 3.0.1 */\n");
 179 }
 180
 181 /* Emit code which will convert the C-format table to a
 182    (define_conditions) form, which the MD reader can understand.
 183    The result will be added to the set of files scanned by
 184    'downstream' generators.  */
 185 static void
 186 write_writer (void)
 187 {
 188   puts ("int\n"
 189         "main(void)\n"
 190         "{\n"
 191         "  unsigned int i;\n"
 192         "  const char *p;\n"
 193         "  puts (\"(define_conditions [\");\n"
 194         "#if GCC_VERSION >= 3001\n"
 195         "  for (i = 0; i < ARRAY_SIZE (insn_conditions) - 1; i++)\n"
 196         "    {\n"
 197         "      printf (\"  (%d \\\"\", insn_conditions[i].value);\n"
 198         "      for (p = insn_conditions[i].expr; *p; p++)\n"
 199         "        {\n"
 200         "          switch (*p)\n"
 201         "            {\n"
 202         "            case '\\\\':\n"
 203         "            case '\\\"': putchar ('\\\\'); break;\n"
 204         "            default: break;\n"
 205         "            }\n"
 206         "          putchar (*p);\n"
 207         "        }\n"
 208         "      puts (\"\\\")\");\n"
 209         "    }\n"
 210         "#endif /* gcc >= 3.0.1 */\n"
 211         "  puts (\"])\");\n"
 212         "  fflush (stdout);\n"
 213         "return ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE;\n"
 214         "}");
 215 }
 216
 217 int
 218 main (int argc, const char **argv)
 219 {
 220   progname = "genconditions";
 221
 222   if (!init_rtx_reader_args (argc, argv))
 223     return (FATAL_EXIT_CODE);
 224
 225   /* Read the machine description.  */
 226   md_rtx_info info;
 227   while (read_md_rtx (&info))
 228     {
 229       rtx def = info.def;
 230       add_c_test (get_c_test (def), -1);
 231       switch (GET_CODE (def))
 232         {
 233         case DEFINE_INSN:
 234         case DEFINE_EXPAND:
 235           /* except.h needs to know whether there is an eh_return
 236              pattern in the machine description.  */
 237           if (!strcmp (XSTR (def, 0), "eh_return"))
 238             saw_eh_return = 1;
 239           break;
 240
 241         default:
 242           break;
 243         }
 244     }
 245
 246   write_header ();
 247   write_conditions ();
 248   write_writer ();
 249
 250   fflush (stdout);
 251   return (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
 252 }