gcc/genconditions.c

   1 /* Process machine description and calculate constant conditions.
   2    Copyright (C) 2001-2017 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 #include \"bconfig.h\"\n\
  54 #define INCLUDE_STRING\n\
  55 #include \"system.h\"\n\
  56 \n\
  57 /* It is necessary, but not entirely safe, to include the headers below\n\
  58    in a generator program.  As a defensive measure, don't do so when the\n\
  59    table isn't going to have anything in it.  */\n\
  60 #if GCC_VERSION >= 3001\n\
  61 \n\
  62 /* Do not allow checking to confuse the issue.  */\n\
  63 #undef CHECKING_P\n\
  64 #define CHECKING_P 0\n\
  65 #undef ENABLE_TREE_CHECKING\n\
  66 #undef ENABLE_RTL_CHECKING\n\
  67 #undef ENABLE_RTL_FLAG_CHECKING\n\
  68 #undef ENABLE_GC_CHECKING\n\
  69 #undef ENABLE_GC_ALWAYS_COLLECT\n\
  70 \n\
  71 #include \"coretypes.h\"\n\
  72 #include \"tm.h\"\n\
  73 #include \"insn-constants.h\"\n\
  74 #include \"rtl.h\"\n\
  75 #include \"memmodel.h\"\n\
  76 #include \"tm_p.h\"\n\
  77 #include \"hard-reg-set.h\"\n\
  78 #include \"function.h\"\n\
  79 #include \"emit-rtl.h\"\n\
  80 \n\
  81 /* Fake - insn-config.h doesn't exist yet.  */\n\
  82 #define MAX_RECOG_OPERANDS 10\n\
  83 #define MAX_DUP_OPERANDS 10\n\
  84 #define MAX_INSNS_PER_SPLIT 5\n\
  85 \n\
  86 #include \"regs.h\"\n\
  87 #include \"recog.h\"\n\
  88 #include \"output.h\"\n\
  89 #include \"flags.h\"\n\
  90 #include \"hard-reg-set.h\"\n\
  91 #include \"predict.h\"\n\
  92 #include \"basic-block.h\"\n\
  93 #include \"bitmap.h\"\n\
  94 #include \"df.h\"\n\
  95 #include \"resource.h\"\n\
  96 #include \"diagnostic-core.h\"\n\
  97 #include \"reload.h\"\n\
  98 #include \"tm-constrs.h\"\n");
  99
 100   if (saw_eh_return)
 101     puts ("#define HAVE_eh_return 1");
 102   puts ("#include \"except.h\"\n");
 103
 104   puts ("\
 105 /* Dummy external declarations.  */\n\
 106 extern rtx_insn *insn;\n\
 107 extern rtx ins1;\n\
 108 extern rtx operands[];\n\
 109 \n\
 110 #endif /* gcc >= 3.0.1 */\n");
 111 }
 112
 113 /* Write out one entry in the conditions table, using the data pointed
 114    to by SLOT.  Each entry looks like this:
 115
 116    { "! optimize_size && ! TARGET_READ_MODIFY_WRITE",
 117      __builtin_constant_p (! optimize_size && ! TARGET_READ_MODIFY_WRITE)
 118      ? (int) (! optimize_size && ! TARGET_READ_MODIFY_WRITE)
 119      : -1) },  */
 120
 121 static int
 122 write_one_condition (void **slot, void * ARG_UNUSED (dummy))
 123 {
 124   const struct c_test *test = * (const struct c_test **) slot;
 125   const char *p;
 126
 127   rtx_reader_ptr->print_md_ptr_loc (test->expr);
 128   fputs ("  { \"", stdout);
 129   for (p = test->expr; *p; p++)
 130     {
 131       switch (*p)
 132         {
 133         case '\n': fputs ("\\n\\", stdout); break;
 134         case '\\':
 135         case '\"': putchar ('\\'); break;
 136         default: break;
 137         }
 138       putchar (*p);
 139     }
 140
 141   fputs ("\",\n    __builtin_constant_p ", stdout);
 142   rtx_reader_ptr->print_c_condition (test->expr);
 143   fputs ("\n    ? (int) ", stdout);
 144   rtx_reader_ptr->print_c_condition (test->expr);
 145   fputs ("\n    : -1 },\n", stdout);
 146   return 1;
 147 }
 148
 149 /* Write out the complete conditions table, its size, and a flag
 150    indicating that gensupport.c can now do insn elision.  */
 151 static void
 152 write_conditions (void)
 153 {
 154   puts ("\
 155 /* Structure definition duplicated from gensupport.h rather than\n\
 156    drag in that file and its dependencies.  */\n\
 157 struct c_test\n\
 158 {\n\
 159   const char *expr;\n\
 160   int value;\n\
 161 };\n\
 162 \n\
 163 /* This table lists each condition found in the machine description.\n\
 164    Each condition is mapped to its truth value (0 or 1), or -1 if that\n\
 165    cannot be calculated at compile time.\n\
 166    If we don't have __builtin_constant_p, or it's not acceptable in array\n\
 167    initializers, fall back to assuming that all conditions potentially\n\
 168    vary at run time.  It works in 3.0.1 and later; 3.0 only when not\n\
 169    optimizing.  */\n\
 170 \n\
 171 #if GCC_VERSION >= 3001\n\
 172 static const struct c_test insn_conditions[] = {\n");
 173
 174   traverse_c_tests (write_one_condition, 0);
 175
 176   puts ("\n};\n#endif /* gcc >= 3.0.1 */\n");
 177 }
 178
 179 /* Emit code which will convert the C-format table to a
 180    (define_conditions) form, which the MD reader can understand.
 181    The result will be added to the set of files scanned by
 182    'downstream' generators.  */
 183 static void
 184 write_writer (void)
 185 {
 186   puts ("int\n"
 187         "main(void)\n"
 188         "{\n"
 189         "  unsigned int i;\n"
 190         "  const char *p;\n"
 191         "  puts (\"(define_conditions [\");\n"
 192         "#if GCC_VERSION >= 3001\n"
 193         "  for (i = 0; i < ARRAY_SIZE (insn_conditions); i++)\n"
 194         "    {\n"
 195         "      printf (\"  (%d \\\"\", insn_conditions[i].value);\n"
 196         "      for (p = insn_conditions[i].expr; *p; p++)\n"
 197         "        {\n"
 198         "          switch (*p)\n"
 199         "            {\n"
 200         "            case '\\\\':\n"
 201         "            case '\\\"': putchar ('\\\\'); break;\n"
 202         "            default: break;\n"
 203         "            }\n"
 204         "          putchar (*p);\n"
 205         "        }\n"
 206         "      puts (\"\\\")\");\n"
 207         "    }\n"
 208         "#endif /* gcc >= 3.0.1 */\n"
 209         "  puts (\"])\");\n"
 210         "  fflush (stdout);\n"
 211         "return ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE;\n"
 212         "}");
 213 }
 214
 215 int
 216 main (int argc, const char **argv)
 217 {
 218   progname = "genconditions";
 219
 220   if (!init_rtx_reader_args (argc, argv))
 221     return (FATAL_EXIT_CODE);
 222
 223   /* Read the machine description.  */
 224   md_rtx_info info;
 225   while (read_md_rtx (&info))
 226     {
 227       rtx def = info.def;
 228       add_c_test (get_c_test (def), -1);
 229       switch (GET_CODE (def))
 230         {
 231         case DEFINE_INSN:
 232         case DEFINE_EXPAND:
 233           /* except.h needs to know whether there is an eh_return
 234              pattern in the machine description.  */
 235           if (!strcmp (XSTR (def, 0), "eh_return"))
 236             saw_eh_return = 1;
 237           break;
 238
 239         default:
 240           break;
 241         }
 242     }
 243
 244   write_header ();
 245   write_conditions ();
 246   write_writer ();
 247
 248   fflush (stdout);
 249   return (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
 250 }