gcc/genconditions.c

   1 /* Process machine description and calculate constant conditions.
   2    Copyright (C) 2001-2016 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 #define INCLUDE_STRING\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 CHECKING_P\n\
  64 #define CHECKING_P 0\n\
  65 #undef ENABLE_TREE_CHECKING\n\
  66 #undef ENABLE_RTL_CHECKING\n\
  67 #undef ENABLE_RTL_FLAG_CHECKING\n\
  68 #undef ENABLE_GC_CHECKING\n\
  69 #undef ENABLE_GC_ALWAYS_COLLECT\n\
  70 \n\
  71 #include \"coretypes.h\"\n\
  72 #include \"tm.h\"\n\
  73 #include \"insn-constants.h\"\n\
  74 #include \"rtl.h\"\n\
  75 #include \"tm_p.h\"\n\
  76 #include \"hard-reg-set.h\"\n\
  77 #include \"function.h\"\n\
  78 #include \"emit-rtl.h\"\n\
  79 \n\
  80 /* Fake - insn-config.h doesn't exist yet.  */\n\
  81 #define MAX_RECOG_OPERANDS 10\n\
  82 #define MAX_DUP_OPERANDS 10\n\
  83 #define MAX_INSNS_PER_SPLIT 5\n\
  84 \n\
  85 #include \"regs.h\"\n\
  86 #include \"recog.h\"\n\
  87 #include \"output.h\"\n\
  88 #include \"flags.h\"\n\
  89 #include \"hard-reg-set.h\"\n\
  90 #include \"predict.h\"\n\
  91 #include \"basic-block.h\"\n\
  92 #include \"bitmap.h\"\n\
  93 #include \"df.h\"\n\
  94 #include \"resource.h\"\n\
  95 #include \"diagnostic-core.h\"\n\
  96 #include \"reload.h\"\n\
  97 #include \"tm-constrs.h\"\n");
  98
  99   if (saw_eh_return)
 100     puts ("#define HAVE_eh_return 1");
 101   puts ("#include \"except.h\"\n");
 102
 103   puts ("\
 104 /* Dummy external declarations.  */\n\
 105 extern rtx_insn *insn;\n\
 106 extern rtx ins1;\n\
 107 extern rtx operands[];\n\
 108 \n\
 109 #endif /* gcc >= 3.0.1 */\n");
 110 }
 111
 112 /* Write out one entry in the conditions table, using the data pointed
 113    to by SLOT.  Each entry looks like this:
 114
 115    { "! optimize_size && ! TARGET_READ_MODIFY_WRITE",
 116      __builtin_constant_p (! optimize_size && ! TARGET_READ_MODIFY_WRITE)
 117      ? (int) (! optimize_size && ! TARGET_READ_MODIFY_WRITE)
 118      : -1) },  */
 119
 120 static int
 121 write_one_condition (void **slot, void * ARG_UNUSED (dummy))
 122 {
 123   const struct c_test *test = * (const struct c_test **) slot;
 124   const char *p;
 125
 126   print_md_ptr_loc (test->expr);
 127   fputs ("  { \"", stdout);
 128   for (p = test->expr; *p; p++)
 129     {
 130       switch (*p)
 131         {
 132         case '\n': fputs ("\\n\\", stdout); break;
 133         case '\\':
 134         case '\"': putchar ('\\'); break;
 135         default: break;
 136         }
 137       putchar (*p);
 138     }
 139
 140   fputs ("\",\n    __builtin_constant_p ", stdout);
 141   print_c_condition (test->expr);
 142   fputs ("\n    ? (int) ", stdout);
 143   print_c_condition (test->expr);
 144   fputs ("\n    : -1 },\n", stdout);
 145   return 1;
 146 }
 147
 148 /* Write out the complete conditions table, its size, and a flag
 149    indicating that gensupport.c can now do insn elision.  */
 150 static void
 151 write_conditions (void)
 152 {
 153   puts ("\
 154 /* Structure definition duplicated from gensupport.h rather than\n\
 155    drag in that file and its dependencies.  */\n\
 156 struct c_test\n\
 157 {\n\
 158   const char *expr;\n\
 159   int value;\n\
 160 };\n\
 161 \n\
 162 /* This table lists each condition found in the machine description.\n\
 163    Each condition is mapped to its truth value (0 or 1), or -1 if that\n\
 164    cannot be calculated at compile time.\n\
 165    If we don't have __builtin_constant_p, or it's not acceptable in array\n\
 166    initializers, fall back to assuming that all conditions potentially\n\
 167    vary at run time.  It works in 3.0.1 and later; 3.0 only when not\n\
 168    optimizing.  */\n\
 169 \n\
 170 #if GCC_VERSION >= 3001\n\
 171 static const struct c_test insn_conditions[] = {\n");
 172
 173   traverse_c_tests (write_one_condition, 0);
 174
 175   puts ("\n};\n#endif /* gcc >= 3.0.1 */\n");
 176 }
 177
 178 /* Emit code which will convert the C-format table to a
 179    (define_conditions) form, which the MD reader can understand.
 180    The result will be added to the set of files scanned by
 181    'downstream' generators.  */
 182 static void
 183 write_writer (void)
 184 {
 185   puts ("int\n"
 186         "main(void)\n"
 187         "{\n"
 188         "  unsigned int i;\n"
 189         "  const char *p;\n"
 190         "  puts (\"(define_conditions [\");\n"
 191         "#if GCC_VERSION >= 3001\n"
 192         "  for (i = 0; i < ARRAY_SIZE (insn_conditions); i++)\n"
 193         "    {\n"
 194         "      printf (\"  (%d \\\"\", insn_conditions[i].value);\n"
 195         "      for (p = insn_conditions[i].expr; *p; p++)\n"
 196         "        {\n"
 197         "          switch (*p)\n"
 198         "            {\n"
 199         "            case '\\\\':\n"
 200         "            case '\\\"': putchar ('\\\\'); break;\n"
 201         "            default: break;\n"
 202         "            }\n"
 203         "          putchar (*p);\n"
 204         "        }\n"
 205         "      puts (\"\\\")\");\n"
 206         "    }\n"
 207         "#endif /* gcc >= 3.0.1 */\n"
 208         "  puts (\"])\");\n"
 209         "  fflush (stdout);\n"
 210         "return ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE;\n"
 211         "}");
 212 }
 213
 214 int
 215 main (int argc, const char **argv)
 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   md_rtx_info info;
 224   while (read_md_rtx (&info))
 225     {
 226       rtx def = info.def;
 227       add_c_test (get_c_test (def), -1);
 228       switch (GET_CODE (def))
 229         {
 230         case DEFINE_INSN:
 231         case DEFINE_EXPAND:
 232           /* except.h needs to know whether there is an eh_return
 233              pattern in the machine description.  */
 234           if (!strcmp (XSTR (def, 0), "eh_return"))
 235             saw_eh_return = 1;
 236           break;
 237
 238         default:
 239           break;
 240         }
 241     }
 242
 243   write_header ();
 244   write_conditions ();
 245   write_writer ();
 246
 247   fflush (stdout);
 248   return (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
 249 }