gcc/genconditions.c

   1 /* Process machine description and calculate constant conditions.
   2    Copyright (C) 2001, 2002, 2003 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 = (struct c_test *) xmalloc (sizeof (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 extern int next_insn_tests_no_inequality (rtx);\n");
 123
 124   puts ("\
 125 /* If we don't have __builtin_constant_p, or it's not acceptable in\n\
 126    array initializers, fall back to assuming that all conditions\n\
 127    potentially vary at run time.  It works in 3.0.1 and later; 3.0\n\
 128    only when not optimizing.  */\n\
 129 #if (GCC_VERSION >= 3001) || ((GCC_VERSION == 3000) && !__OPTIMIZE__)\n\
 130 # define MAYBE_EVAL(expr) (__builtin_constant_p(expr) ? (int) (expr) : -1)\n\
 131 #else\n\
 132 # define MAYBE_EVAL(expr) -1\n\
 133 #endif\n");
 134 }
 135
 136 /* Write out one entry in the conditions table, using the data pointed
 137    to by SLOT.  Each entry looks like this:
 138   { "! optimize_size && ! TARGET_READ_MODIFY_WRITE",
 139     MAYBE_EVAL (! optimize_size && ! TARGET_READ_MODIFY_WRITE) },  */
 140
 141 static int
 142 write_one_condition (void **slot, void *dummy ATTRIBUTE_UNUSED)
 143 {
 144   const struct c_test *test = * (const struct c_test **) slot;
 145   const char *p;
 146
 147   fputs ("  { \"", stdout);
 148   for (p = test->expr; *p; p++)
 149     {
 150       if (*p == '\n')
 151         fputs ("\\n\\\n", stdout);
 152       else if (*p == '"')
 153         fputs ("\\\"", stdout);
 154       else
 155         putchar (*p);
 156     }
 157
 158   printf ("\",\n    MAYBE_EVAL (%s) },\n", test->expr);
 159   return 1;
 160 }
 161
 162 /* Write out the complete conditions table, its size, and a flag
 163    indicating that gensupport.c can now do insn elision.  */
 164 static void
 165 write_conditions (void)
 166 {
 167   puts ("\
 168 /* This table lists each condition found in the machine description.\n\
 169    Each condition is mapped to its truth value (0 or 1), or -1 if that\n\
 170    cannot be calculated at compile time. */\n\
 171 \n\
 172 const struct c_test insn_conditions[] = {");
 173
 174   htab_traverse (condition_table, write_one_condition, 0);
 175
 176   puts ("};\n");
 177
 178   printf ("const size_t n_insn_conditions = %lu;\n",
 179           (unsigned long) htab_elements (condition_table));
 180   puts ("const int insn_elision_unavailable = 0;");
 181 }
 182
 183 int
 184 main (int argc, char **argv)
 185 {
 186   rtx desc;
 187   int pattern_lineno; /* not used */
 188   int code;
 189
 190   progname = "genconditions";
 191
 192   if (argc <= 1)
 193     fatal ("No input file name.");
 194
 195   if (init_md_reader (argv[1]) != SUCCESS_EXIT_CODE)
 196     return (FATAL_EXIT_CODE);
 197
 198   condition_table = htab_create (1000, hash_c_test, cmp_c_test, NULL);
 199
 200   /* Read the machine description.  */
 201
 202   while (1)
 203     {
 204       desc = read_md_rtx (&pattern_lineno, &code);
 205       if (desc == NULL)
 206         break;
 207
 208       /* N.B. define_insn_and_split, define_cond_exec are handled
 209          entirely within read_md_rtx; we never see them.  */
 210       switch (GET_CODE (desc))
 211         {
 212         default:
 213           break;
 214
 215         case DEFINE_INSN:
 216         case DEFINE_EXPAND:
 217           add_condition (XSTR (desc, 2));
 218           /* except.h needs to know whether there is an eh_return
 219              pattern in the machine description.  */
 220           if (!strcmp (XSTR (desc, 0), "eh_return"))
 221             saw_eh_return = 1;
 222           break;
 223
 224         case DEFINE_SPLIT:
 225         case DEFINE_PEEPHOLE:
 226         case DEFINE_PEEPHOLE2:
 227           add_condition (XSTR (desc, 1));
 228           break;
 229         }
 230     }
 231
 232   write_header ();
 233   write_conditions ();
 234
 235   fflush (stdout);
 236   return (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
 237 }