gcc/genconditions.c

   1 /* Process machine description and calculate constant conditions.
   2    Copyright (C) 2001, 2002, 2003, 2004 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       (const char *);
  44 static void write_header        (void);
  45 static void write_conditions    (void);
  46 static int write_one_condition  (void **, void *);
  47
  48 /* Record the C test expression EXPR in the condition_table.
  49    Duplicates clobber previous entries, which leaks memory, but
  50    we don't care for this application.  */
  51
  52 static void
  53 add_condition (const char *expr)
  54 {
  55   struct c_test *test;
  56
  57   if (expr[0] == 0)
  58     return;
  59
  60   test = XNEW (struct c_test);
  61   test->expr = expr;
  62
  63   *(htab_find_slot (condition_table, test, INSERT)) = test;
  64 }
  65
  66 /* Generate the header for insn-conditions.c.  */
  67
  68 static void
  69 write_header (void)
  70 {
  71   puts ("\
  72 /* Generated automatically by the program `genconditions' from the target\n\
  73    machine description file.  */\n\
  74 \n\
  75 #include \"bconfig.h\"\n\
  76 #include \"insn-constants.h\"\n");
  77
  78   puts ("\
  79 /* Do not allow checking to confuse the issue.  */\n\
  80 #undef ENABLE_CHECKING\n\
  81 #undef ENABLE_TREE_CHECKING\n\
  82 #undef ENABLE_RTL_CHECKING\n\
  83 #undef ENABLE_RTL_FLAG_CHECKING\n\
  84 #undef ENABLE_GC_CHECKING\n\
  85 #undef ENABLE_GC_ALWAYS_COLLECT\n");
  86
  87   puts ("\
  88 #include \"system.h\"\n\
  89 #include \"coretypes.h\"\n\
  90 #include \"tm.h\"\n\
  91 #include \"rtl.h\"\n\
  92 #include \"tm_p.h\"\n\
  93 #include \"function.h\"\n");
  94
  95   puts ("\
  96 /* Fake - insn-config.h doesn't exist yet.  */\n\
  97 #define MAX_RECOG_OPERANDS 10\n\
  98 #define MAX_DUP_OPERANDS 10\n\
  99 #define MAX_INSNS_PER_SPLIT 5\n");
 100
 101   puts ("\
 102 #include \"regs.h\"\n\
 103 #include \"recog.h\"\n\
 104 #include \"real.h\"\n\
 105 #include \"output.h\"\n\
 106 #include \"flags.h\"\n\
 107 #include \"hard-reg-set.h\"\n\
 108 #include \"resource.h\"\n\
 109 #include \"toplev.h\"\n\
 110 #include \"reload.h\"\n\
 111 #include \"gensupport.h\"\n");
 112
 113   if (saw_eh_return)
 114     puts ("#define HAVE_eh_return 1");
 115   puts ("#include \"except.h\"\n");
 116
 117   puts ("\
 118 /* Dummy external declarations.  */\n\
 119 extern rtx insn;\n\
 120 extern rtx ins1;\n\
 121 extern rtx operands[];\n");
 122
 123   puts ("\
 124 /* If we don't have __builtin_constant_p, or it's not acceptable in\n\
 125    array initializers, fall back to assuming that all conditions\n\
 126    potentially vary at run time.  It works in 3.0.1 and later; 3.0\n\
 127    only when not optimizing.  */\n\
 128 #if (GCC_VERSION >= 3001) || ((GCC_VERSION == 3000) && !__OPTIMIZE__)\n\
 129 # define MAYBE_EVAL(expr) (__builtin_constant_p(expr) ? (int) (expr) : -1)\n\
 130 #else\n\
 131 # define MAYBE_EVAL(expr) -1\n\
 132 #endif\n");
 133 }
 134
 135 /* Write out one entry in the conditions table, using the data pointed
 136    to by SLOT.  Each entry looks like this:
 137   { "! optimize_size && ! TARGET_READ_MODIFY_WRITE",
 138     MAYBE_EVAL (! optimize_size && ! TARGET_READ_MODIFY_WRITE) },  */
 139
 140 static int
 141 write_one_condition (void **slot, void * ARG_UNUSED (dummy))
 142 {
 143   const struct c_test *test = * (const struct c_test **) slot;
 144   const char *p;
 145
 146   fputs ("  { \"", stdout);
 147   for (p = test->expr; *p; p++)
 148     {
 149       if (*p == '\n')
 150         fputs ("\\n\\\n", stdout);
 151       else if (*p == '"')
 152         fputs ("\\\"", stdout);
 153       else
 154         putchar (*p);
 155     }
 156
 157   printf ("\",\n    MAYBE_EVAL (%s) },\n", test->expr);
 158   return 1;
 159 }
 160
 161 /* Write out the complete conditions table, its size, and a flag
 162    indicating that gensupport.c can now do insn elision.  */
 163 static void
 164 write_conditions (void)
 165 {
 166   puts ("\
 167 /* This table lists each condition found in the machine description.\n\
 168    Each condition is mapped to its truth value (0 or 1), or -1 if that\n\
 169    cannot be calculated at compile time. */\n\
 170 \n\
 171 const struct c_test insn_conditions[] = {");
 172
 173   htab_traverse (condition_table, write_one_condition, 0);
 174
 175   puts ("};\n");
 176
 177   printf ("const size_t n_insn_conditions = %lu;\n",
 178           (unsigned long) htab_elements (condition_table));
 179   puts ("const int insn_elision_unavailable = 0;");
 180 }
 181
 182 int
 183 main (int argc, char **argv)
 184 {
 185   rtx desc;
 186   int pattern_lineno; /* not used */
 187   int code;
 188
 189   progname = "genconditions";
 190
 191   if (init_md_reader_args (argc, argv) != SUCCESS_EXIT_CODE)
 192     return (FATAL_EXIT_CODE);
 193
 194   condition_table = htab_create (1000, hash_c_test, cmp_c_test, NULL);
 195
 196   /* Read the machine description.  */
 197
 198   while (1)
 199     {
 200       desc = read_md_rtx (&pattern_lineno, &code);
 201       if (desc == NULL)
 202         break;
 203
 204       /* N.B. define_insn_and_split, define_cond_exec are handled
 205          entirely within read_md_rtx; we never see them.  */
 206       switch (GET_CODE (desc))
 207         {
 208         default:
 209           break;
 210
 211         case DEFINE_INSN:
 212         case DEFINE_EXPAND:
 213           add_condition (XSTR (desc, 2));
 214           /* except.h needs to know whether there is an eh_return
 215              pattern in the machine description.  */
 216           if (!strcmp (XSTR (desc, 0), "eh_return"))
 217             saw_eh_return = 1;
 218           break;
 219
 220         case DEFINE_SPLIT:
 221         case DEFINE_PEEPHOLE:
 222         case DEFINE_PEEPHOLE2:
 223           add_condition (XSTR (desc, 1));
 224           break;
 225         }
 226     }
 227
 228   write_header ();
 229   write_conditions ();
 230
 231   fflush (stdout);
 232   return (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
 233 }