gcc/genconditions.c

   1 /* Process machine description and calculate constant conditions.
   2    Copyright (C) 2001, 2002, 2003, 2004, 2005, 2007
   3    Free Software Foundation, Inc.
   4
   5    This file is part of GCC.
   6
   7    GCC is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3, or (at your option)
  10    any later version.
  11
  12    GCC is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with GCC; see the file COPYING3.  If not see
  19    <http://www.gnu.org/licenses/>.  */
  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 \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 ENABLE_CHECKING\n\
  64 #undef ENABLE_TREE_CHECKING\n\
  65 #undef ENABLE_RTL_CHECKING\n\
  66 #undef ENABLE_RTL_FLAG_CHECKING\n\
  67 #undef ENABLE_GC_CHECKING\n\
  68 #undef ENABLE_GC_ALWAYS_COLLECT\n\
  69 \n\
  70 #include \"coretypes.h\"\n\
  71 #include \"tm.h\"\n\
  72 #include \"insn-constants.h\"\n\
  73 #include \"rtl.h\"\n\
  74 #include \"tm_p.h\"\n\
  75 #include \"function.h\"\n\
  76 \n\
  77 /* Fake - insn-config.h doesn't exist yet.  */\n\
  78 #define MAX_RECOG_OPERANDS 10\n\
  79 #define MAX_DUP_OPERANDS 10\n\
  80 #define MAX_INSNS_PER_SPLIT 5\n\
  81 \n\
  82 #include \"regs.h\"\n\
  83 #include \"recog.h\"\n\
  84 #include \"real.h\"\n\
  85 #include \"output.h\"\n\
  86 #include \"flags.h\"\n\
  87 #include \"hard-reg-set.h\"\n\
  88 #include \"resource.h\"\n\
  89 #include \"toplev.h\"\n\
  90 #include \"reload.h\"\n\
  91 #include \"tm-constrs.h\"\n");
  92
  93   if (saw_eh_return)
  94     puts ("#define HAVE_eh_return 1");
  95   puts ("#include \"except.h\"\n");
  96
  97   puts ("\
  98 /* Dummy external declarations.  */\n\
  99 extern rtx insn;\n\
 100 extern rtx ins1;\n\
 101 extern rtx operands[];\n\
 102 \n\
 103 #endif /* gcc >= 3.0.1 */\n");
 104 }
 105
 106 /* Write out one entry in the conditions table, using the data pointed
 107    to by SLOT.  Each entry looks like this:
 108
 109    { "! optimize_size && ! TARGET_READ_MODIFY_WRITE",
 110      __builtin_constant_p (! optimize_size && ! TARGET_READ_MODIFY_WRITE)
 111      ? (int) (! optimize_size && ! TARGET_READ_MODIFY_WRITE)
 112      : -1) },  */
 113
 114 static int
 115 write_one_condition (void **slot, void * ARG_UNUSED (dummy))
 116 {
 117   const struct c_test *test = * (const struct c_test **) slot;
 118   const char *p;
 119
 120   print_rtx_ptr_loc (test->expr);
 121   fputs ("  { \"", stdout);
 122   for (p = test->expr; *p; p++)
 123     {
 124       switch (*p)
 125         {
 126         case '\n': fputs ("\\n\\", stdout); break;
 127         case '\\':
 128         case '\"': putchar ('\\'); break;
 129         default: break;
 130         }
 131       putchar (*p);
 132     }
 133
 134   fputs ("\",\n    __builtin_constant_p ", stdout);
 135   print_c_condition (test->expr);
 136   fputs ("\n    ? (int) ", stdout);
 137   print_c_condition (test->expr);
 138   fputs ("\n    : -1 },\n", stdout);
 139   return 1;
 140 }
 141
 142 /* Write out the complete conditions table, its size, and a flag
 143    indicating that gensupport.c can now do insn elision.  */
 144 static void
 145 write_conditions (void)
 146 {
 147   puts ("\
 148 /* Structure definition duplicated from gensupport.h rather than\n\
 149    drag in that file and its dependencies.  */\n\
 150 struct c_test\n\
 151 {\n\
 152   const char *expr;\n\
 153   int value;\n\
 154 };\n\
 155 \n\
 156 /* This table lists each condition found in the machine description.\n\
 157    Each condition is mapped to its truth value (0 or 1), or -1 if that\n\
 158    cannot be calculated at compile time.\n\
 159    If we don't have __builtin_constant_p, or it's not acceptable in array\n\
 160    initializers, fall back to assuming that all conditions potentially\n\
 161    vary at run time.  It works in 3.0.1 and later; 3.0 only when not\n\
 162    optimizing.  */\n\
 163 \n\
 164 #if GCC_VERSION >= 3001\n\
 165 static const struct c_test insn_conditions[] = {\n");
 166
 167   traverse_c_tests (write_one_condition, 0);
 168
 169   puts ("\n};\n#endif /* gcc >= 3.0.1 */\n");
 170 }
 171
 172 /* Emit code which will convert the C-format table to a
 173    (define_conditions) form, which the MD reader can understand.
 174    The result will be added to the set of files scanned by
 175    'downstream' generators.  */
 176 static void
 177 write_writer (void)
 178 {
 179   puts ("int\n"
 180         "main(void)\n"
 181         "{\n"
 182         "  unsigned int i;\n"
 183         "  const char *p;\n"
 184         "  puts (\"(define_conditions [\");\n"
 185         "#if GCC_VERSION >= 3001\n"
 186         "  for (i = 0; i < ARRAY_SIZE (insn_conditions); i++)\n"
 187         "    {\n"
 188         "      printf (\"  (%d \\\"\", insn_conditions[i].value);\n"
 189         "      for (p = insn_conditions[i].expr; *p; p++)\n"
 190         "        {\n"
 191         "          switch (*p)\n"
 192         "            {\n"
 193         "            case '\\\\':\n"
 194         "            case '\\\"': putchar ('\\\\'); break;\n"
 195         "            default: break;\n"
 196         "            }\n"
 197         "          putchar (*p);\n"
 198         "        }\n"
 199         "      puts (\"\\\")\");\n"
 200         "    }\n"
 201         "#endif /* gcc >= 3.0.1 */\n"
 202         "  puts (\"])\");\n"
 203         "  fflush (stdout);\n"
 204         "return ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE;\n"
 205         "}");
 206 }
 207
 208 int
 209 main (int argc, char **argv)
 210 {
 211   rtx desc;
 212   int pattern_lineno; /* not used */
 213   int code;
 214
 215   progname = "genconditions";
 216
 217   if (init_md_reader_args (argc, argv) != SUCCESS_EXIT_CODE)
 218     return (FATAL_EXIT_CODE);
 219
 220   /* Read the machine description.  */
 221   while (1)
 222     {
 223       desc = read_md_rtx (&pattern_lineno, &code);
 224       if (desc == NULL)
 225         break;
 226
 227       /* N.B. define_insn_and_split, define_cond_exec are handled
 228          entirely within read_md_rtx; we never see them.  */
 229       switch (GET_CODE (desc))
 230         {
 231         default:
 232           break;
 233
 234         case DEFINE_INSN:
 235         case DEFINE_EXPAND:
 236           add_c_test (XSTR (desc, 2), -1);
 237           /* except.h needs to know whether there is an eh_return
 238              pattern in the machine description.  */
 239           if (!strcmp (XSTR (desc, 0), "eh_return"))
 240             saw_eh_return = 1;
 241           break;
 242
 243         case DEFINE_SPLIT:
 244         case DEFINE_PEEPHOLE:
 245         case DEFINE_PEEPHOLE2:
 246           add_c_test (XSTR (desc, 1), -1);
 247           break;
 248         }
 249     }
 250
 251   write_header ();
 252   write_conditions ();
 253   write_writer ();
 254
 255   fflush (stdout);
 256   return (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
 257 }