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