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 CHECKING_P\n\
  63 #define CHECKING_P 0\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 \"rtl.h\"\n\
  74 #include \"tm_p.h\"\n\
  75 #include \"hard-reg-set.h\"\n\
  76 #include \"function.h\"\n\
  77 #include \"emit-rtl.h\"\n\
  78 \n\
  79 /* Fake - insn-config.h doesn't exist yet.  */\n\
  80 #define MAX_RECOG_OPERANDS 10\n\
  81 #define MAX_DUP_OPERANDS 10\n\
  82 #define MAX_INSNS_PER_SPLIT 5\n\
  83 \n\
  84 #include \"regs.h\"\n\
  85 #include \"recog.h\"\n\
  86 #include \"output.h\"\n\
  87 #include \"flags.h\"\n\
  88 #include \"hard-reg-set.h\"\n\
  89 #include \"predict.h\"\n\
  90 #include \"basic-block.h\"\n\
  91 #include \"bitmap.h\"\n\
  92 #include \"df.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   progname = "genconditions";
 217
 218   if (!init_rtx_reader_args (argc, argv))
 219     return (FATAL_EXIT_CODE);
 220
 221   /* Read the machine description.  */
 222   md_rtx_info info;
 223   while (read_md_rtx (&info))
 224     {
 225       rtx def = info.def;
 226       add_c_test (get_c_test (def), -1);
 227       switch (GET_CODE (def))
 228         {
 229         case DEFINE_INSN:
 230         case DEFINE_EXPAND:
 231           /* except.h needs to know whether there is an eh_return
 232              pattern in the machine description.  */
 233           if (!strcmp (XSTR (def, 0), "eh_return"))
 234             saw_eh_return = 1;
 235           break;
 236
 237         default:
 238           break;
 239         }
 240     }
 241
 242   write_header ();
 243   write_conditions ();
 244   write_writer ();
 245
 246   fflush (stdout);
 247   return (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
 248 }