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 "hashtab.h"
35#include "read-md.h"
36#include "gensupport.h"
37
38/* so we can include except.h in the generated file.  */
39static int saw_eh_return;
40
41static void write_header	(void);
42static void write_conditions	(void);
43static int write_one_condition	(void **, void *);
44
45/* Generate the header for insn-conditions.c.  */
46
47static void
48write_header (void)
49{
50  puts ("\
51/* Generated automatically by the program `genconditions' from the target\n\
52   machine description file.  */\n\
53\n\
54#include \"bconfig.h\"\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 ENABLE_CHECKING\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 \"ggc.h\"\n\
74#include \"rtl.h\"\n\
75#include \"tm_p.h\"\n\
76#include \"hashtab.h\"\n\
77#include \"hash-set.h\"\n\
78#include \"hard-reg-set.h\"\n\
79#include \"function.h\"\n\
80\n\
81/* Fake - insn-config.h doesn't exist yet.  */\n\
82#define MAX_RECOG_OPERANDS 10\n\
83#define MAX_DUP_OPERANDS 10\n\
84#define MAX_INSNS_PER_SPLIT 5\n\
85\n\
86#include \"regs.h\"\n\
87#include \"recog.h\"\n\
88#include \"output.h\"\n\
89#include \"flags.h\"\n\
90#include \"hard-reg-set.h\"\n\
91#include \"predict.h\"\n\
92#include \"basic-block.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\
104extern rtx_insn *insn;\n\
105extern rtx ins1;\n\
106extern 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
119static int
120write_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.  */
149static void
150write_conditions (void)
151{
152  puts ("\
153/* Structure definition duplicated from gensupport.h rather than\n\
154   drag in that file and its dependencies.  */\n\
155struct 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\
170static 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.  */
181static void
182write_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
213int
214main (int argc, char **argv)
215{
216  rtx desc;
217  int pattern_lineno; /* not used */
218  int code;
219
220  progname = "genconditions";
221
222  if (!init_rtx_reader_args (argc, argv))
223    return (FATAL_EXIT_CODE);
224
225  /* Read the machine description.  */
226  while (1)
227    {
228      desc = read_md_rtx (&pattern_lineno, &code);
229      if (desc == NULL)
230	break;
231
232      /* N.B. define_insn_and_split, define_cond_exec are handled
233	 entirely within read_md_rtx; we never see them.  */
234      switch (GET_CODE (desc))
235	{
236	default:
237	  break;
238
239	case DEFINE_INSN:
240	case DEFINE_EXPAND:
241	  add_c_test (XSTR (desc, 2), -1);
242	  /* except.h needs to know whether there is an eh_return
243	     pattern in the machine description.  */
244	  if (!strcmp (XSTR (desc, 0), "eh_return"))
245	    saw_eh_return = 1;
246	  break;
247
248	case DEFINE_SPLIT:
249	case DEFINE_PEEPHOLE:
250	case DEFINE_PEEPHOLE2:
251	  add_c_test (XSTR (desc, 1), -1);
252	  break;
253	}
254    }
255
256  write_header ();
257  write_conditions ();
258  write_writer ();
259
260  fflush (stdout);
261  return (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
262}
263