gcc/genconditions.c

   1 /* Process machine description and calculate constant conditions.
   2    Copyright (C) 2001, 2002 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, 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, 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 htab_t condition_table;
  42
  43 static void add_condition       PARAMS ((const char *));
  44 static void write_header        PARAMS ((void));
  45 static void write_conditions    PARAMS ((void));
  46 static int write_one_condition  PARAMS ((PTR *, PTR));
  47
  48 extern int main                 PARAMS ((int, char **));
  49
  50 /* Record the C test expression EXPR in the condition_table.
  51    Duplicates clobber previous entries, which leaks memory, but
  52    we don't care for this application.  */
  53
  54 static void
  55 add_condition (expr)
  56      const char *expr;
  57 {
  58   struct c_test *test;
  59
  60   if (expr[0] == 0)
  61     return;
  62
  63   test = (struct c_test *) xmalloc (sizeof (struct c_test));
  64   test->expr = expr;
  65
  66   *(htab_find_slot (condition_table, test, INSERT)) = test;
  67 }
  68
  69 /* Generate the header for insn-conditions.c.  */
  70
  71 static void
  72 write_header ()
  73 {
  74   puts ("\
  75 /* Generated automatically by the program `genconditions' from the target\n\
  76    machine description file.  */\n\
  77 \n\
  78 #include \"bconfig.h\"\n\
  79 #include \"insn-constants.h\"\n");
  80
  81   puts ("\
  82 /* Do not allow checking to confuse the issue.  */\n\
  83 #undef ENABLE_CHECKING\n\
  84 #undef ENABLE_TREE_CHECKING\n\
  85 #undef ENABLE_RTL_CHECKING\n\
  86 #undef ENABLE_RTL_FLAG_CHECKING\n\
  87 #undef ENABLE_GC_CHECKING\n\
  88 #undef ENABLE_GC_ALWAYS_COLLECT\n");
  89
  90   puts ("\
  91 #include \"system.h\"\n\
  92 #include \"coretypes.h\"\n\
  93 #include \"tm.h\"\n\
  94 #include \"rtl.h\"\n\
  95 #include \"tm_p.h\"\n\
  96 #include \"function.h\"\n");
  97
  98   puts ("\
  99 /* Fake - insn-config.h doesn't exist yet.  */\n\
 100 #define MAX_RECOG_OPERANDS 10\n\
 101 #define MAX_DUP_OPERANDS 10\n\
 102 #define MAX_INSNS_PER_SPLIT 5\n");
 103
 104   puts ("\
 105 #include \"regs.h\"\n\
 106 #include \"recog.h\"\n\
 107 #include \"real.h\"\n\
 108 #include \"output.h\"\n\
 109 #include \"flags.h\"\n\
 110 #include \"hard-reg-set.h\"\n\
 111 #include \"resource.h\"\n\
 112 #include \"toplev.h\"\n\
 113 #include \"reload.h\"\n\
 114 #include \"gensupport.h\"\n");
 115
 116   if (saw_eh_return)
 117     puts ("#define HAVE_eh_return 1");
 118   puts ("#include \"except.h\"\n");
 119
 120   puts ("\
 121 /* Dummy external declarations.  */\n\
 122 extern rtx insn;\n\
 123 extern rtx ins1;\n\
 124 extern rtx operands[];\n\
 125 extern int next_insn_tests_no_inequality PARAMS ((rtx));\n");
 126
 127   puts ("\
 128 /* If we don't have __builtin_constant_p, or it's not acceptable in\n\
 129    array initializers, fall back to assuming that all conditions\n\
 130    potentially vary at run time.  It works in 3.0.1 and later; 3.0\n\
 131    only when not optimizing.  */\n\
 132 #if (GCC_VERSION >= 3001) || ((GCC_VERSION == 3000) && !__OPTIMIZE__)\n\
 133 # define MAYBE_EVAL(expr) (__builtin_constant_p(expr) ? (int) (expr) : -1)\n\
 134 #else\n\
 135 # define MAYBE_EVAL(expr) -1\n\
 136 #endif\n");
 137 }
 138
 139 /* Write out one entry in the conditions table, using the data pointed
 140    to by SLOT.  Each entry looks like this:
 141   { "! optimize_size && ! TARGET_READ_MODIFY_WRITE",
 142     MAYBE_EVAL (! optimize_size && ! TARGET_READ_MODIFY_WRITE) },  */
 143
 144 static int
 145 write_one_condition (slot, dummy)
 146      PTR *slot;
 147      PTR dummy ATTRIBUTE_UNUSED;
 148 {
 149   const struct c_test *test = * (const struct c_test **) slot;
 150   const char *p;
 151
 152   fputs ("  { \"", stdout);
 153   for (p = test->expr; *p; p++)
 154     {
 155       if (*p == '\n')
 156         fputs ("\\n\\\n", stdout);
 157       else if (*p == '"')
 158         fputs ("\\\"", stdout);
 159       else
 160         putchar (*p);
 161     }
 162
 163   printf ("\",\n    MAYBE_EVAL (%s) },\n", test->expr);
 164   return 1;
 165 }
 166
 167 /* Write out the complete conditions table, its size, and a flag
 168    indicating that gensupport.c can now do insn elision.  */
 169 static void
 170 write_conditions ()
 171 {
 172   puts ("\
 173 /* This table lists each condition found in the machine description.\n\
 174    Each condition is mapped to its truth value (0 or 1), or -1 if that\n\
 175    cannot be calculated at compile time. */\n\
 176 \n\
 177 const struct c_test insn_conditions[] = {");
 178
 179   htab_traverse (condition_table, write_one_condition, 0);
 180
 181   puts ("};\n");
 182
 183   printf ("const size_t n_insn_conditions = %lu;\n",
 184           (unsigned long) htab_elements (condition_table));
 185   puts ("const int insn_elision_unavailable = 0;");
 186 }
 187
 188 int
 189 main (argc, argv)
 190      int argc;
 191      char **argv;
 192 {
 193   rtx desc;
 194   int pattern_lineno; /* not used */
 195   int code;
 196
 197   progname = "genconditions";
 198
 199   if (argc <= 1)
 200     fatal ("No input file name.");
 201
 202   if (init_md_reader (argv[1]) != SUCCESS_EXIT_CODE)
 203     return (FATAL_EXIT_CODE);
 204
 205   condition_table = htab_create (1000, hash_c_test, cmp_c_test, NULL);
 206
 207   /* Read the machine description.  */
 208
 209   while (1)
 210     {
 211       desc = read_md_rtx (&pattern_lineno, &code);
 212       if (desc == NULL)
 213         break;
 214
 215       /* N.B. define_insn_and_split, define_cond_exec are handled
 216          entirely within read_md_rtx; we never see them.  */
 217       switch (GET_CODE (desc))
 218         {
 219         default:
 220           break;
 221
 222         case DEFINE_INSN:
 223         case DEFINE_EXPAND:
 224           add_condition (XSTR (desc, 2));
 225           /* except.h needs to know whether there is an eh_return
 226              pattern in the machine description.  */
 227           if (!strcmp (XSTR (desc, 0), "eh_return"))
 228             saw_eh_return = 1;
 229           break;
 230
 231         case DEFINE_SPLIT:
 232         case DEFINE_PEEPHOLE:
 233         case DEFINE_PEEPHOLE2:
 234           add_condition (XSTR (desc, 1));
 235           break;
 236         }
 237     }
 238
 239   write_header ();
 240   write_conditions ();
 241
 242   fflush (stdout);
 243   return (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
 244 }