gcc/genconditions.c

   1 /* Process machine description and calculate constant conditions.
   2    Copyright (C) 2001, 2002, 2003, 2004, 2005 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 2, 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 COPYING.  If not, write to
  18    the Free Software Foundation, 51 Franklin Street, Fifth Floor,
  19    Boston, MA 02110-1301, USA.  */
  20
  21 /* In a machine description, all of the insn patterns - define_insn,
  22    define_expand, define_split, define_peephole, define_peephole2 -
  23    contain an optional C expression which makes the final decision
  24    about whether or not this pattern is usable.  That expression may
  25    turn out to be always false when the compiler is built.  If it is,
  26    most of the programs that generate code from the machine
  27    description can simply ignore the entire pattern.  */
  28
  29 #include "bconfig.h"
  30 #include "system.h"
  31 #include "coretypes.h"
  32 #include "tm.h"
  33 #include "rtl.h"
  34 #include "errors.h"
  35 #include "hashtab.h"
  36 #include "gensupport.h"
  37
  38 /* so we can include except.h in the generated file.  */
  39 static int saw_eh_return;
  40
  41 static void write_header        (void);
  42 static void write_conditions    (void);
  43 static int write_one_condition  (void **, void *);
  44
  45 /* Generate the header for insn-conditions.c.  */
  46
  47 static void
  48 write_header (void)
  49 {
  50   puts ("\
  51 /* Generated automatically by the program `genconditions' from the target\n\
  52    machine description file.  */\n\
  53 \n\
  54 #include \"bconfig.h\"\n\
  55 #include \"system.h\"\n");
  56
  57   puts ("\
  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 ENABLE_CHECKING\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
  71   puts ("\
  72 #include \"coretypes.h\"\n\
  73 #include \"tm.h\"\n\
  74 #include \"insn-constants.h\"\n\
  75 #include \"rtl.h\"\n\
  76 #include \"tm_p.h\"\n\
  77 #include \"function.h\"\n");
  78
  79   puts ("\
  80 /* Fake - insn-config.h doesn't exist yet.  */\n\
  81 #define MAX_RECOG_OPERANDS 10\n\
  82 #define MAX_DUP_OPERANDS 10\n\
  83 #define MAX_INSNS_PER_SPLIT 5\n");
  84
  85   puts ("\
  86 #include \"regs.h\"\n\
  87 #include \"recog.h\"\n\
  88 #include \"real.h\"\n\
  89 #include \"output.h\"\n\
  90 #include \"flags.h\"\n\
  91 #include \"hard-reg-set.h\"\n\
  92 #include \"resource.h\"\n\
  93 #include \"toplev.h\"\n\
  94 #include \"reload.h\"\n");
  95
  96   if (saw_eh_return)
  97     puts ("#define HAVE_eh_return 1");
  98   puts ("#include \"except.h\"\n");
  99
 100   puts ("\
 101 /* Dummy external declarations.  */\n\
 102 extern rtx insn;\n\
 103 extern rtx ins1;\n\
 104 extern rtx operands[];\n\
 105 \n\
 106 #endif /* gcc >= 3.0.1 */\n");
 107 }
 108
 109 /* Write out one entry in the conditions table, using the data pointed
 110    to by SLOT.  Each entry looks like this:
 111
 112    { "! optimize_size && ! TARGET_READ_MODIFY_WRITE",
 113      __builtin_constant_p (! optimize_size && ! TARGET_READ_MODIFY_WRITE)
 114      ? (int) (! optimize_size && ! TARGET_READ_MODIFY_WRITE)
 115      : -1) },  */
 116
 117 static int
 118 write_one_condition (void **slot, void * ARG_UNUSED (dummy))
 119 {
 120   const struct c_test *test = * (const struct c_test **) slot;
 121   const char *p;
 122
 123   print_rtx_ptr_loc (test->expr);
 124   fputs ("  { \"", stdout);
 125   for (p = test->expr; *p; p++)
 126     {
 127       switch (*p)
 128         {
 129         case '\n': fputs ("\\n\\", stdout); break;
 130         case '\\':
 131         case '\"': putchar ('\\'); break;
 132         default: break;
 133         }
 134       putchar (*p);
 135     }
 136
 137   printf ("\",\n    __builtin_constant_p ");
 138   print_c_condition (test->expr);
 139   printf ("\n    ? (int) ");
 140   print_c_condition (test->expr);
 141   printf ("\n    : -1 },\n");
 142   return 1;
 143 }
 144
 145 /* Write out the complete conditions table, its size, and a flag
 146    indicating that gensupport.c can now do insn elision.  */
 147 static void
 148 write_conditions (void)
 149 {
 150   puts ("\
 151 /* Structure definition duplicated from gensupport.h rather than\n\
 152    drag in that file and its dependencies.  */\n\
 153 struct c_test\n\
 154 {\n\
 155   const char *expr;\n\
 156   int value;\n\
 157 };\n");
 158
 159   puts ("\
 160 /* This table lists each condition found in the machine description.\n\
 161    Each condition is mapped to its truth value (0 or 1), or -1 if that\n\
 162    cannot be calculated at compile time.\n\
 163    If we don't have __builtin_constant_p, or it's not acceptable in array\n\
 164    initializers, fall back to assuming that all conditions potentially\n\
 165    vary at run time.  It works in 3.0.1 and later; 3.0 only when not\n\
 166    optimizing.  */\n\
 167 \n\
 168 static const struct c_test insn_conditions[] = {\n\
 169 #if GCC_VERSION >= 3001\n");
 170
 171   traverse_c_tests (write_one_condition, 0);
 172
 173   puts ("\n#endif /* gcc >= 3.0.1 */\n};\n");
 174 }
 175
 176 /* Emit code which will convert the C-format table to a
 177    (define_conditions) form, which the MD reader can understand.
 178    The result will be added to the set of files scanned by
 179    'downstream' generators.  */
 180 static void
 181 write_writer (void)
 182 {
 183   puts ("int\n"
 184         "main(void)\n"
 185         "{\n"
 186         "  unsigned int i;\n"
 187         "  const char *p;\n"
 188         "  puts (\"(define_conditions [\");\n"
 189         "  for (i = 0; i < ARRAY_SIZE (insn_conditions); i++)\n"
 190         "    {\n"
 191         "      printf (\"  (%d \\\"\", insn_conditions[i].value);\n"
 192         "      for (p = insn_conditions[i].expr; *p; p++)\n"
 193         "        {\n"
 194         "          switch (*p)\n"
 195         "            {\n"
 196         "            case '\\\\':\n"
 197         "            case '\\\"': putchar ('\\\\'); break;\n"
 198         "            default: break;\n"
 199         "            }\n"
 200         "          putchar (*p);\n"
 201         "        }\n"
 202         "      puts (\"\\\")\");\n"
 203         "    }");
 204   puts ("  puts (\"])\");\n"
 205         "  fflush (stdout);\n"
 206         "return ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE;\n"
 207         "}");
 208 }
 209
 210 int
 211 main (int argc, char **argv)
 212 {
 213   rtx desc;
 214   int pattern_lineno; /* not used */
 215   int code;
 216
 217   progname = "genconditions";
 218
 219   if (init_md_reader_args (argc, argv) != SUCCESS_EXIT_CODE)
 220     return (FATAL_EXIT_CODE);
 221
 222   /* Read the machine description.  */
 223   while (1)
 224     {
 225       desc = read_md_rtx (&pattern_lineno, &code);
 226       if (desc == NULL)
 227         break;
 228
 229       /* N.B. define_insn_and_split, define_cond_exec are handled
 230          entirely within read_md_rtx; we never see them.  */
 231       switch (GET_CODE (desc))
 232         {
 233         default:
 234           break;
 235
 236         case DEFINE_INSN:
 237         case DEFINE_EXPAND:
 238           add_c_test (XSTR (desc, 2), -1);
 239           /* except.h needs to know whether there is an eh_return
 240              pattern in the machine description.  */
 241           if (!strcmp (XSTR (desc, 0), "eh_return"))
 242             saw_eh_return = 1;
 243           break;
 244
 245         case DEFINE_SPLIT:
 246         case DEFINE_PEEPHOLE:
 247         case DEFINE_PEEPHOLE2:
 248           add_c_test (XSTR (desc, 1), -1);
 249           break;
 250         }
 251     }
 252
 253   write_header ();
 254   write_conditions ();
 255   write_writer ();
 256
 257   fflush (stdout);
 258   return (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
 259 }