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 \"bitmap.h\"\n\
  91 #include \"df.h\"\n\
  92 #include \"resource.h\"\n\
  93 #include \"diagnostic-core.h\"\n\
  94 #include \"reload.h\"\n\
  95 #include \"tm-constrs.h\"\n");
  96
  97   if (saw_eh_return)
  98     puts ("#define HAVE_eh_return 1");
  99   puts ("#include \"except.h\"\n");
 100
 101   puts ("\
 102 /* Dummy external declarations.  */\n\
 103 extern rtx_insn *insn;\n\
 104 extern rtx ins1;\n\
 105 extern rtx operands[];\n\
 106 \n\
 107 #endif /* gcc >= 3.0.1 */\n");
 108 }
 109
 110 /* Write out one entry in the conditions table, using the data pointed
 111    to by SLOT.  Each entry looks like this:
 112
 113    { "! optimize_size && ! TARGET_READ_MODIFY_WRITE",
 114      __builtin_constant_p (! optimize_size && ! TARGET_READ_MODIFY_WRITE)
 115      ? (int) (! optimize_size && ! TARGET_READ_MODIFY_WRITE)
 116      : -1) },  */
 117
 118 static int
 119 write_one_condition (void **slot, void * ARG_UNUSED (dummy))
 120 {
 121   const struct c_test *test = * (const struct c_test **) slot;
 122   const char *p;
 123
 124   print_md_ptr_loc (test->expr);
 125   fputs ("  { \"", stdout);
 126   for (p = test->expr; *p; p++)
 127     {
 128       switch (*p)
 129         {
 130         case '\n': fputs ("\\n\\", stdout); break;
 131         case '\\':
 132         case '\"': putchar ('\\'); break;
 133         default: break;
 134         }
 135       putchar (*p);
 136     }
 137
 138   fputs ("\",\n    __builtin_constant_p ", stdout);
 139   print_c_condition (test->expr);
 140   fputs ("\n    ? (int) ", stdout);
 141   print_c_condition (test->expr);
 142   fputs ("\n    : -1 },\n", stdout);
 143   return 1;
 144 }
 145
 146 /* Write out the complete conditions table, its size, and a flag
 147    indicating that gensupport.c can now do insn elision.  */
 148 static void
 149 write_conditions (void)
 150 {
 151   puts ("\
 152 /* Structure definition duplicated from gensupport.h rather than\n\
 153    drag in that file and its dependencies.  */\n\
 154 struct c_test\n\
 155 {\n\
 156   const char *expr;\n\
 157   int value;\n\
 158 };\n\
 159 \n\
 160 /* This table lists each condition found in the machine description.\n\
 161    Each condition is mapped to its truth value (0 or 1), or -1 if that\n\
 162    cannot be calculated at compile time.\n\
 163    If we don't have __builtin_constant_p, or it's not acceptable in array\n\
 164    initializers, fall back to assuming that all conditions potentially\n\
 165    vary at run time.  It works in 3.0.1 and later; 3.0 only when not\n\
 166    optimizing.  */\n\
 167 \n\
 168 #if GCC_VERSION >= 3001\n\
 169 static const struct c_test insn_conditions[] = {\n");
 170
 171   traverse_c_tests (write_one_condition, 0);
 172
 173   puts ("\n};\n#endif /* gcc >= 3.0.1 */\n");
 174 }
 175
 176 /* Emit code which will convert the C-format table to a
 177    (define_conditions) form, which the MD reader can understand.
 178    The result will be added to the set of files scanned by
 179    'downstream' generators.  */
 180 static void
 181 write_writer (void)
 182 {
 183   puts ("int\n"
 184         "main(void)\n"
 185         "{\n"
 186         "  unsigned int i;\n"
 187         "  const char *p;\n"
 188         "  puts (\"(define_conditions [\");\n"
 189         "#if GCC_VERSION >= 3001\n"
 190         "  for (i = 0; i < ARRAY_SIZE (insn_conditions); i++)\n"
 191         "    {\n"
 192         "      printf (\"  (%d \\\"\", insn_conditions[i].value);\n"
 193         "      for (p = insn_conditions[i].expr; *p; p++)\n"
 194         "        {\n"
 195         "          switch (*p)\n"
 196         "            {\n"
 197         "            case '\\\\':\n"
 198         "            case '\\\"': putchar ('\\\\'); break;\n"
 199         "            default: break;\n"
 200         "            }\n"
 201         "          putchar (*p);\n"
 202         "        }\n"
 203         "      puts (\"\\\")\");\n"
 204         "    }\n"
 205         "#endif /* gcc >= 3.0.1 */\n"
 206         "  puts (\"])\");\n"
 207         "  fflush (stdout);\n"
 208         "return ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE;\n"
 209         "}");
 210 }
 211
 212 int
 213 main (int argc, char **argv)
 214 {
 215   progname = "genconditions";
 216
 217   if (!init_rtx_reader_args (argc, argv))
 218     return (FATAL_EXIT_CODE);
 219
 220   /* Read the machine description.  */
 221   md_rtx_info info;
 222   while (read_md_rtx (&info))
 223     {
 224       rtx def = info.def;
 225       /* N.B. define_insn_and_split, define_cond_exec are handled
 226          entirely within read_md_rtx; we never see them.  */
 227       switch (GET_CODE (def))
 228         {
 229         case DEFINE_INSN:
 230         case DEFINE_EXPAND:
 231           add_c_test (XSTR (def, 2), -1);
 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         case DEFINE_SPLIT:
 239         case DEFINE_PEEPHOLE:
 240         case DEFINE_PEEPHOLE2:
 241           add_c_test (XSTR (def, 1), -1);
 242           break;
 243
 244         default:
 245           break;
 246         }
 247     }
 248
 249   write_header ();
 250   write_conditions ();
 251   write_writer ();
 252
 253   fflush (stdout);
 254   return (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
 255 }