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 "read-md.h"
  35 #include "gensupport.h"
  36
  37 /* so we can include except.h in the generated file.  */
  38 static int saw_eh_return;
  39
  40 static void write_header        (void);
  41 static void write_conditions    (void);
  42 static int write_one_condition  (void **, void *);
  43
  44 /* Generate the header for insn-conditions.c.  */
  45
  46 static void
  47 write_header (void)
  48 {
  49   puts ("\
  50 /* Generated automatically by the program `genconditions' from the target\n\
  51    machine description file.  */\n\
  52 \n\
  53 #include \"bconfig.h\"\n\
  54 #include \"system.h\"\n\
  55 \n\
  56 /* It is necessary, but not entirely safe, to include the headers below\n\
  57    in a generator program.  As a defensive measure, don't do so when the\n\
  58    table isn't going to have anything in it.  */\n\
  59 #if GCC_VERSION >= 3001\n\
  60 \n\
  61 /* Do not allow checking to confuse the issue.  */\n\
  62 #undef ENABLE_CHECKING\n\
  63 #undef ENABLE_TREE_CHECKING\n\
  64 #undef ENABLE_RTL_CHECKING\n\
  65 #undef ENABLE_RTL_FLAG_CHECKING\n\
  66 #undef ENABLE_GC_CHECKING\n\
  67 #undef ENABLE_GC_ALWAYS_COLLECT\n\
  68 \n\
  69 #include \"coretypes.h\"\n\
  70 #include \"tm.h\"\n\
  71 #include \"insn-constants.h\"\n\
  72 #include \"rtl.h\"\n\
  73 #include \"tm_p.h\"\n\
  74 #include \"hard-reg-set.h\"\n\
  75 #include \"function.h\"\n\
  76 #include \"emit-rtl.h\"\n\
  77 \n\
  78 /* Fake - insn-config.h doesn't exist yet.  */\n\
  79 #define MAX_RECOG_OPERANDS 10\n\
  80 #define MAX_DUP_OPERANDS 10\n\
  81 #define MAX_INSNS_PER_SPLIT 5\n\
  82 \n\
  83 #include \"regs.h\"\n\
  84 #include \"recog.h\"\n\
  85 #include \"output.h\"\n\
  86 #include \"flags.h\"\n\
  87 #include \"hard-reg-set.h\"\n\
  88 #include \"predict.h\"\n\
  89 #include \"basic-block.h\"\n\
  90 #include \"resource.h\"\n\
  91 #include \"diagnostic-core.h\"\n\
  92 #include \"reload.h\"\n\
  93 #include \"tm-constrs.h\"\n");
  94
  95   if (saw_eh_return)
  96     puts ("#define HAVE_eh_return 1");
  97   puts ("#include \"except.h\"\n");
  98
  99   puts ("\
 100 /* Dummy external declarations.  */\n\
 101 extern rtx_insn *insn;\n\
 102 extern rtx ins1;\n\
 103 extern rtx operands[];\n\
 104 \n\
 105 #endif /* gcc >= 3.0.1 */\n");
 106 }
 107
 108 /* Write out one entry in the conditions table, using the data pointed
 109    to by SLOT.  Each entry looks like this:
 110
 111    { "! optimize_size && ! TARGET_READ_MODIFY_WRITE",
 112      __builtin_constant_p (! optimize_size && ! TARGET_READ_MODIFY_WRITE)
 113      ? (int) (! optimize_size && ! TARGET_READ_MODIFY_WRITE)
 114      : -1) },  */
 115
 116 static int
 117 write_one_condition (void **slot, void * ARG_UNUSED (dummy))
 118 {
 119   const struct c_test *test = * (const struct c_test **) slot;
 120   const char *p;
 121
 122   print_md_ptr_loc (test->expr);
 123   fputs ("  { \"", stdout);
 124   for (p = test->expr; *p; p++)
 125     {
 126       switch (*p)
 127         {
 128         case '\n': fputs ("\\n\\", stdout); break;
 129         case '\\':
 130         case '\"': putchar ('\\'); break;
 131         default: break;
 132         }
 133       putchar (*p);
 134     }
 135
 136   fputs ("\",\n    __builtin_constant_p ", stdout);
 137   print_c_condition (test->expr);
 138   fputs ("\n    ? (int) ", stdout);
 139   print_c_condition (test->expr);
 140   fputs ("\n    : -1 },\n", stdout);
 141   return 1;
 142 }
 143
 144 /* Write out the complete conditions table, its size, and a flag
 145    indicating that gensupport.c can now do insn elision.  */
 146 static void
 147 write_conditions (void)
 148 {
 149   puts ("\
 150 /* Structure definition duplicated from gensupport.h rather than\n\
 151    drag in that file and its dependencies.  */\n\
 152 struct c_test\n\
 153 {\n\
 154   const char *expr;\n\
 155   int value;\n\
 156 };\n\
 157 \n\
 158 /* This table lists each condition found in the machine description.\n\
 159    Each condition is mapped to its truth value (0 or 1), or -1 if that\n\
 160    cannot be calculated at compile time.\n\
 161    If we don't have __builtin_constant_p, or it's not acceptable in array\n\
 162    initializers, fall back to assuming that all conditions potentially\n\
 163    vary at run time.  It works in 3.0.1 and later; 3.0 only when not\n\
 164    optimizing.  */\n\
 165 \n\
 166 #if GCC_VERSION >= 3001\n\
 167 static const struct c_test insn_conditions[] = {\n");
 168
 169   traverse_c_tests (write_one_condition, 0);
 170
 171   puts ("\n};\n#endif /* gcc >= 3.0.1 */\n");
 172 }
 173
 174 /* Emit code which will convert the C-format table to a
 175    (define_conditions) form, which the MD reader can understand.
 176    The result will be added to the set of files scanned by
 177    'downstream' generators.  */
 178 static void
 179 write_writer (void)
 180 {
 181   puts ("int\n"
 182         "main(void)\n"
 183         "{\n"
 184         "  unsigned int i;\n"
 185         "  const char *p;\n"
 186         "  puts (\"(define_conditions [\");\n"
 187         "#if GCC_VERSION >= 3001\n"
 188         "  for (i = 0; i < ARRAY_SIZE (insn_conditions); i++)\n"
 189         "    {\n"
 190         "      printf (\"  (%d \\\"\", insn_conditions[i].value);\n"
 191         "      for (p = insn_conditions[i].expr; *p; p++)\n"
 192         "        {\n"
 193         "          switch (*p)\n"
 194         "            {\n"
 195         "            case '\\\\':\n"
 196         "            case '\\\"': putchar ('\\\\'); break;\n"
 197         "            default: break;\n"
 198         "            }\n"
 199         "          putchar (*p);\n"
 200         "        }\n"
 201         "      puts (\"\\\")\");\n"
 202         "    }\n"
 203         "#endif /* gcc >= 3.0.1 */\n"
 204         "  puts (\"])\");\n"
 205         "  fflush (stdout);\n"
 206         "return ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE;\n"
 207         "}");
 208 }
 209
 210 int
 211 main (int argc, char **argv)
 212 {
 213   rtx desc;
 214   int pattern_lineno; /* not used */
 215   int code;
 216
 217   progname = "genconditions";
 218
 219   if (!init_rtx_reader_args (argc, argv))
 220     return (FATAL_EXIT_CODE);
 221
 222   /* Read the machine description.  */
 223   while (1)
 224     {
 225       desc = read_md_rtx (&pattern_lineno, &code);
 226       if (desc == NULL)
 227         break;
 228
 229       /* N.B. define_insn_and_split, define_cond_exec are handled
 230          entirely within read_md_rtx; we never see them.  */
 231       switch (GET_CODE (desc))
 232         {
 233         default:
 234           break;
 235
 236         case DEFINE_INSN:
 237         case DEFINE_EXPAND:
 238           add_c_test (XSTR (desc, 2), -1);
 239           /* except.h needs to know whether there is an eh_return
 240              pattern in the machine description.  */
 241           if (!strcmp (XSTR (desc, 0), "eh_return"))
 242             saw_eh_return = 1;
 243           break;
 244
 245         case DEFINE_SPLIT:
 246         case DEFINE_PEEPHOLE:
 247         case DEFINE_PEEPHOLE2:
 248           add_c_test (XSTR (desc, 1), -1);
 249           break;
 250         }
 251     }
 252
 253   write_header ();
 254   write_conditions ();
 255   write_writer ();
 256
 257   fflush (stdout);
 258   return (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
 259 }