gcc/genconditions.c

   1 /* Process machine description and calculate constant conditions.
   2    Copyright (C) 2001-2017 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 #define USE_ENUM_MODES\n\
  71 \n\
  72 #include \"coretypes.h\"\n\
  73 #include \"tm.h\"\n\
  74 #include \"insn-constants.h\"\n\
  75 #include \"rtl.h\"\n\
  76 #include \"memmodel.h\"\n\
  77 #include \"tm_p.h\"\n\
  78 #include \"hard-reg-set.h\"\n\
  79 #include \"function.h\"\n\
  80 #include \"emit-rtl.h\"\n\
  81 \n\
  82 /* Fake - insn-config.h doesn't exist yet.  */\n\
  83 #define MAX_RECOG_OPERANDS 10\n\
  84 #define MAX_DUP_OPERANDS 10\n\
  85 #define MAX_INSNS_PER_SPLIT 5\n\
  86 \n\
  87 #include \"regs.h\"\n\
  88 #include \"recog.h\"\n\
  89 #include \"output.h\"\n\
  90 #include \"flags.h\"\n\
  91 #include \"hard-reg-set.h\"\n\
  92 #include \"predict.h\"\n\
  93 #include \"basic-block.h\"\n\
  94 #include \"bitmap.h\"\n\
  95 #include \"df.h\"\n\
  96 #include \"resource.h\"\n\
  97 #include \"diagnostic-core.h\"\n\
  98 #include \"reload.h\"\n\
  99 #include \"tm-constrs.h\"\n");
 100
 101   if (saw_eh_return)
 102     puts ("#define HAVE_eh_return 1");
 103   puts ("#include \"except.h\"\n");
 104
 105   puts ("\
 106 /* Dummy external declarations.  */\n\
 107 extern rtx_insn *insn;\n\
 108 extern rtx ins1;\n\
 109 extern rtx operands[];\n\
 110 \n\
 111 #endif /* gcc >= 3.0.1 */\n");
 112 }
 113
 114 /* Write out one entry in the conditions table, using the data pointed
 115    to by SLOT.  Each entry looks like this:
 116
 117    { "! optimize_size && ! TARGET_READ_MODIFY_WRITE",
 118      __builtin_constant_p (! optimize_size && ! TARGET_READ_MODIFY_WRITE)
 119      ? (int) (! optimize_size && ! TARGET_READ_MODIFY_WRITE)
 120      : -1) },  */
 121
 122 static int
 123 write_one_condition (void **slot, void * ARG_UNUSED (dummy))
 124 {
 125   const struct c_test *test = * (const struct c_test **) slot;
 126   const char *p;
 127
 128   rtx_reader_ptr->print_md_ptr_loc (test->expr);
 129   fputs ("  { \"", stdout);
 130   for (p = test->expr; *p; p++)
 131     {
 132       switch (*p)
 133         {
 134         case '\n': fputs ("\\n\\", stdout); break;
 135         case '\\':
 136         case '\"': putchar ('\\'); break;
 137         default: break;
 138         }
 139       putchar (*p);
 140     }
 141
 142   fputs ("\",\n    __builtin_constant_p ", stdout);
 143   rtx_reader_ptr->print_c_condition (test->expr);
 144   fputs ("\n    ? (int) ", stdout);
 145   rtx_reader_ptr->print_c_condition (test->expr);
 146   fputs ("\n    : -1 },\n", stdout);
 147   return 1;
 148 }
 149
 150 /* Write out the complete conditions table, its size, and a flag
 151    indicating that gensupport.c can now do insn elision.  */
 152 static void
 153 write_conditions (void)
 154 {
 155   puts ("\
 156 /* Structure definition duplicated from gensupport.h rather than\n\
 157    drag in that file and its dependencies.  */\n\
 158 struct c_test\n\
 159 {\n\
 160   const char *expr;\n\
 161   int value;\n\
 162 };\n\
 163 \n\
 164 /* This table lists each condition found in the machine description.\n\
 165    Each condition is mapped to its truth value (0 or 1), or -1 if that\n\
 166    cannot be calculated at compile time.\n\
 167    If we don't have __builtin_constant_p, or it's not acceptable in array\n\
 168    initializers, fall back to assuming that all conditions potentially\n\
 169    vary at run time.  It works in 3.0.1 and later; 3.0 only when not\n\
 170    optimizing.  */\n\
 171 \n\
 172 #if GCC_VERSION >= 3001\n\
 173 static const struct c_test insn_conditions[] = {\n");
 174
 175   traverse_c_tests (write_one_condition, 0);
 176
 177   puts ("\n};\n#endif /* gcc >= 3.0.1 */\n");
 178 }
 179
 180 /* Emit code which will convert the C-format table to a
 181    (define_conditions) form, which the MD reader can understand.
 182    The result will be added to the set of files scanned by
 183    'downstream' generators.  */
 184 static void
 185 write_writer (void)
 186 {
 187   puts ("int\n"
 188         "main(void)\n"
 189         "{\n"
 190         "  unsigned int i;\n"
 191         "  const char *p;\n"
 192         "  puts (\"(define_conditions [\");\n"
 193         "#if GCC_VERSION >= 3001\n"
 194         "  for (i = 0; i < ARRAY_SIZE (insn_conditions); i++)\n"
 195         "    {\n"
 196         "      printf (\"  (%d \\\"\", insn_conditions[i].value);\n"
 197         "      for (p = insn_conditions[i].expr; *p; p++)\n"
 198         "        {\n"
 199         "          switch (*p)\n"
 200         "            {\n"
 201         "            case '\\\\':\n"
 202         "            case '\\\"': putchar ('\\\\'); break;\n"
 203         "            default: break;\n"
 204         "            }\n"
 205         "          putchar (*p);\n"
 206         "        }\n"
 207         "      puts (\"\\\")\");\n"
 208         "    }\n"
 209         "#endif /* gcc >= 3.0.1 */\n"
 210         "  puts (\"])\");\n"
 211         "  fflush (stdout);\n"
 212         "return ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE;\n"
 213         "}");
 214 }
 215
 216 int
 217 main (int argc, const char **argv)
 218 {
 219   progname = "genconditions";
 220
 221   if (!init_rtx_reader_args (argc, argv))
 222     return (FATAL_EXIT_CODE);
 223
 224   /* Read the machine description.  */
 225   md_rtx_info info;
 226   while (read_md_rtx (&info))
 227     {
 228       rtx def = info.def;
 229       add_c_test (get_c_test (def), -1);
 230       switch (GET_CODE (def))
 231         {
 232         case DEFINE_INSN:
 233         case DEFINE_EXPAND:
 234           /* except.h needs to know whether there is an eh_return
 235              pattern in the machine description.  */
 236           if (!strcmp (XSTR (def, 0), "eh_return"))
 237             saw_eh_return = 1;
 238           break;
 239
 240         default:
 241           break;
 242         }
 243     }
 244
 245   write_header ();
 246   write_conditions ();
 247   write_writer ();
 248
 249   fflush (stdout);
 250   return (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
 251 }