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 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 /* If we don't have __builtin_constant_p, or it's not acceptable in array\n\
  90    initializers, fall back to assuming that all conditions potentially\n\
  91    vary at run time.  It works in 3.0.1 and later; 3.0 only when not\n\
  92    optimizing.  */\n\
  93 #if GCC_VERSION < 3001\n\
  94 #include \"dummy-conditions.c\"\n\
  95 #else\n\
  96 #include \"coretypes.h\"\n\
  97 #include \"tm.h\"\n\
  98 #include \"rtl.h\"\n\
  99 #include \"tm_p.h\"\n\
 100 #include \"function.h\"\n");
 101
 102   puts ("\
 103 /* Fake - insn-config.h doesn't exist yet.  */\n\
 104 #define MAX_RECOG_OPERANDS 10\n\
 105 #define MAX_DUP_OPERANDS 10\n\
 106 #define MAX_INSNS_PER_SPLIT 5\n");
 107
 108   puts ("\
 109 #include \"regs.h\"\n\
 110 #include \"recog.h\"\n\
 111 #include \"real.h\"\n\
 112 #include \"output.h\"\n\
 113 #include \"flags.h\"\n\
 114 #include \"hard-reg-set.h\"\n\
 115 #include \"resource.h\"\n\
 116 #include \"toplev.h\"\n\
 117 #include \"reload.h\"\n\
 118 #include \"gensupport.h\"\n");
 119
 120   if (saw_eh_return)
 121     puts ("#define HAVE_eh_return 1");
 122   puts ("#include \"except.h\"\n");
 123
 124   puts ("\
 125 /* Dummy external declarations.  */\n\
 126 extern rtx insn;\n\
 127 extern rtx ins1;\n\
 128 extern rtx operands[];\n");
 129 }
 130
 131 /* Write out one entry in the conditions table, using the data pointed
 132    to by SLOT.  Each entry looks like this:
 133
 134    { "! optimize_size && ! TARGET_READ_MODIFY_WRITE",
 135      __builtin_constant_p (! optimize_size && ! TARGET_READ_MODIFY_WRITE)
 136      ? (int) (! optimize_size && ! TARGET_READ_MODIFY_WRITE)
 137      : -1) },  */
 138
 139 static int
 140 write_one_condition (void **slot, void * ARG_UNUSED (dummy))
 141 {
 142   const struct c_test *test = * (const struct c_test **) slot;
 143   const char *p;
 144
 145   print_rtx_ptr_loc (test->expr);
 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    __builtin_constant_p ");
 158   print_c_condition (test->expr);
 159   printf ("\n    ? (int) ");
 160   print_c_condition (test->expr);
 161   printf ("\n    : -1 },\n");
 162   return 1;
 163 }
 164
 165 /* Write out the complete conditions table, its size, and a flag
 166    indicating that gensupport.c can now do insn elision.  */
 167 static void
 168 write_conditions (void)
 169 {
 170   puts ("\
 171 /* This table lists each condition found in the machine description.\n\
 172    Each condition is mapped to its truth value (0 or 1), or -1 if that\n\
 173    cannot be calculated at compile time. */\n\
 174 \n\
 175 const struct c_test insn_conditions[] = {");
 176
 177   htab_traverse (condition_table, write_one_condition, 0);
 178
 179   puts ("};\n");
 180
 181   printf ("const size_t n_insn_conditions = %lu;\n",
 182           (unsigned long) htab_elements (condition_table));
 183   puts ("const int insn_elision_unavailable = 0;\n#endif");
 184 }
 185
 186 int
 187 main (int argc, char **argv)
 188 {
 189   rtx desc;
 190   int pattern_lineno; /* not used */
 191   int code;
 192
 193   progname = "genconditions";
 194
 195   if (init_md_reader_args (argc, argv) != 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 }