gcc/genconditions.c

   1 /* Process machine description and calculate constant conditions.
   2    Copyright (C) 2001-2015 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 3, 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 COPYING3.  If not see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 /* In a machine description, all of the insn patterns - define_insn,
  21    define_expand, define_split, define_peephole, define_peephole2 -
  22    contain an optional C expression which makes the final decision
  23    about whether or not this pattern is usable.  That expression may
  24    turn out to be always false when the compiler is built.  If it is,
  25    most of the programs that generate code from the machine
  26    description can simply ignore the entire pattern.  */
  27
  28 #include "bconfig.h"
  29 #include "system.h"
  30 #include "coretypes.h"
  31 #include "tm.h"
  32 #include "rtl.h"
  33 #include "errors.h"
  34 #include "hashtab.h"
  35 #include "read-md.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 \"ggc.h\"\n\
  74 #include \"rtl.h\"\n\
  75 #include \"tm_p.h\"\n\
  76 #include \"hashtab.h\"\n\
  77 #include \"hash-set.h\"\n\
  78 #include \"hard-reg-set.h\"\n\
  79 #include \"function.h\"\n\
  80 \n\
  81 /* Fake - insn-config.h doesn't exist yet.  */\n\
  82 #define MAX_RECOG_OPERANDS 10\n\
  83 #define MAX_DUP_OPERANDS 10\n\
  84 #define MAX_INSNS_PER_SPLIT 5\n\
  85 \n\
  86 #include \"regs.h\"\n\
  87 #include \"recog.h\"\n\
  88 #include \"output.h\"\n\
  89 #include \"flags.h\"\n\
  90 #include \"hard-reg-set.h\"\n\
  91 #include \"predict.h\"\n\
  92 #include \"basic-block.h\"\n\
  93 #include \"resource.h\"\n\
  94 #include \"diagnostic-core.h\"\n\
  95 #include \"reload.h\"\n\
  96 #include \"tm-constrs.h\"\n");
  97
  98   if (saw_eh_return)
  99     puts ("#define HAVE_eh_return 1");
 100   puts ("#include \"except.h\"\n");
 101
 102   puts ("\
 103 /* Dummy external declarations.  */\n\
 104 extern rtx_insn *insn;\n\
 105 extern rtx ins1;\n\
 106 extern rtx operands[];\n\
 107 \n\
 108 #endif /* gcc >= 3.0.1 */\n");
 109 }
 110
 111 /* Write out one entry in the conditions table, using the data pointed
 112    to by SLOT.  Each entry looks like this:
 113
 114    { "! optimize_size && ! TARGET_READ_MODIFY_WRITE",
 115      __builtin_constant_p (! optimize_size && ! TARGET_READ_MODIFY_WRITE)
 116      ? (int) (! optimize_size && ! TARGET_READ_MODIFY_WRITE)
 117      : -1) },  */
 118
 119 static int
 120 write_one_condition (void **slot, void * ARG_UNUSED (dummy))
 121 {
 122   const struct c_test *test = * (const struct c_test **) slot;
 123   const char *p;
 124
 125   print_md_ptr_loc (test->expr);
 126   fputs ("  { \"", stdout);
 127   for (p = test->expr; *p; p++)
 128     {
 129       switch (*p)
 130         {
 131         case '\n': fputs ("\\n\\", stdout); break;
 132         case '\\':
 133         case '\"': putchar ('\\'); break;
 134         default: break;
 135         }
 136       putchar (*p);
 137     }
 138
 139   fputs ("\",\n    __builtin_constant_p ", stdout);
 140   print_c_condition (test->expr);
 141   fputs ("\n    ? (int) ", stdout);
 142   print_c_condition (test->expr);
 143   fputs ("\n    : -1 },\n", stdout);
 144   return 1;
 145 }
 146
 147 /* Write out the complete conditions table, its size, and a flag
 148    indicating that gensupport.c can now do insn elision.  */
 149 static void
 150 write_conditions (void)
 151 {
 152   puts ("\
 153 /* Structure definition duplicated from gensupport.h rather than\n\
 154    drag in that file and its dependencies.  */\n\
 155 struct c_test\n\
 156 {\n\
 157   const char *expr;\n\
 158   int value;\n\
 159 };\n\
 160 \n\
 161 /* This table lists each condition found in the machine description.\n\
 162    Each condition is mapped to its truth value (0 or 1), or -1 if that\n\
 163    cannot be calculated at compile time.\n\
 164    If we don't have __builtin_constant_p, or it's not acceptable in array\n\
 165    initializers, fall back to assuming that all conditions potentially\n\
 166    vary at run time.  It works in 3.0.1 and later; 3.0 only when not\n\
 167    optimizing.  */\n\
 168 \n\
 169 #if GCC_VERSION >= 3001\n\
 170 static const struct c_test insn_conditions[] = {\n");
 171
 172   traverse_c_tests (write_one_condition, 0);
 173
 174   puts ("\n};\n#endif /* gcc >= 3.0.1 */\n");
 175 }
 176
 177 /* Emit code which will convert the C-format table to a
 178    (define_conditions) form, which the MD reader can understand.
 179    The result will be added to the set of files scanned by
 180    'downstream' generators.  */
 181 static void
 182 write_writer (void)
 183 {
 184   puts ("int\n"
 185         "main(void)\n"
 186         "{\n"
 187         "  unsigned int i;\n"
 188         "  const char *p;\n"
 189         "  puts (\"(define_conditions [\");\n"
 190         "#if GCC_VERSION >= 3001\n"
 191         "  for (i = 0; i < ARRAY_SIZE (insn_conditions); i++)\n"
 192         "    {\n"
 193         "      printf (\"  (%d \\\"\", insn_conditions[i].value);\n"
 194         "      for (p = insn_conditions[i].expr; *p; p++)\n"
 195         "        {\n"
 196         "          switch (*p)\n"
 197         "            {\n"
 198         "            case '\\\\':\n"
 199         "            case '\\\"': putchar ('\\\\'); break;\n"
 200         "            default: break;\n"
 201         "            }\n"
 202         "          putchar (*p);\n"
 203         "        }\n"
 204         "      puts (\"\\\")\");\n"
 205         "    }\n"
 206         "#endif /* gcc >= 3.0.1 */\n"
 207         "  puts (\"])\");\n"
 208         "  fflush (stdout);\n"
 209         "return ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE;\n"
 210         "}");
 211 }
 212
 213 int
 214 main (int argc, char **argv)
 215 {
 216   rtx desc;
 217   int pattern_lineno; /* not used */
 218   int code;
 219
 220   progname = "genconditions";
 221
 222   if (!init_rtx_reader_args (argc, argv))
 223     return (FATAL_EXIT_CODE);
 224
 225   /* Read the machine description.  */
 226   while (1)
 227     {
 228       desc = read_md_rtx (&pattern_lineno, &code);
 229       if (desc == NULL)
 230         break;
 231
 232       /* N.B. define_insn_and_split, define_cond_exec are handled
 233          entirely within read_md_rtx; we never see them.  */
 234       switch (GET_CODE (desc))
 235         {
 236         default:
 237           break;
 238
 239         case DEFINE_INSN:
 240         case DEFINE_EXPAND:
 241           add_c_test (XSTR (desc, 2), -1);
 242           /* except.h needs to know whether there is an eh_return
 243              pattern in the machine description.  */
 244           if (!strcmp (XSTR (desc, 0), "eh_return"))
 245             saw_eh_return = 1;
 246           break;
 247
 248         case DEFINE_SPLIT:
 249         case DEFINE_PEEPHOLE:
 250         case DEFINE_PEEPHOLE2:
 251           add_c_test (XSTR (desc, 1), -1);
 252           break;
 253         }
 254     }
 255
 256   write_header ();
 257   write_conditions ();
 258   write_writer ();
 259
 260   fflush (stdout);
 261   return (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
 262 }