1/* Process machine description and calculate constant conditions.
2   Copyright (C) 2001-2020 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.  */
38static int saw_eh_return;
39
40static void write_header	(void);
41static void write_conditions	(void);
42static int write_one_condition	(void **, void *);
43
44/* Generate the header for insn-conditions.c.  */
45
46static void
47write_header (void)
48{
49  puts ("\
50/* Generated automatically by the program `genconditions' from the target\n\
51   machine description file.  */\n\
52\n\
53#define IN_TARGET_CODE 1\n\
54#include \"bconfig.h\"\n\
55#define INCLUDE_STRING\n\
56#include \"system.h\"\n\
57\n\
58/* It is necessary, but not entirely safe, to include the headers below\n\
59   in a generator program.  As a defensive measure, don't do so when the\n\
60   table isn't going to have anything in it.  */\n\
61#if GCC_VERSION >= 3001\n\
62\n\
63/* Do not allow checking to confuse the issue.  */\n\
64#undef CHECKING_P\n\
65#define CHECKING_P 0\n\
66#undef ENABLE_TREE_CHECKING\n\
67#undef ENABLE_RTL_CHECKING\n\
68#undef ENABLE_RTL_FLAG_CHECKING\n\
69#undef ENABLE_GC_CHECKING\n\
70#undef ENABLE_GC_ALWAYS_COLLECT\n\
71#define USE_ENUM_MODES\n\
72\n\
73#include \"coretypes.h\"\n\
74#include \"tm.h\"\n\
75#include \"insn-constants.h\"\n\
76#include \"rtl.h\"\n\
77#include \"memmodel.h\"\n\
78#include \"tm_p.h\"\n\
79#include \"hard-reg-set.h\"\n\
80#include \"function.h\"\n\
81#include \"emit-rtl.h\"\n\
82\n\
83/* Fake - insn-config.h doesn't exist yet.  */\n\
84#define MAX_RECOG_OPERANDS 10\n\
85#define MAX_DUP_OPERANDS 10\n\
86#define MAX_INSNS_PER_SPLIT 5\n\
87\n\
88#include \"regs.h\"\n\
89#include \"recog.h\"\n\
90#include \"output.h\"\n\
91#include \"flags.h\"\n\
92#include \"hard-reg-set.h\"\n\
93#include \"predict.h\"\n\
94#include \"basic-block.h\"\n\
95#include \"bitmap.h\"\n\
96#include \"df.h\"\n\
97#include \"resource.h\"\n\
98#include \"diagnostic-core.h\"\n\
99#include \"reload.h\"\n\
100#include \"tm-constrs.h\"\n");
101
102  if (saw_eh_return)
103    puts ("#define HAVE_eh_return 1");
104  puts ("#include \"except.h\"\n");
105
106  puts ("\
107/* Dummy external declarations.  */\n\
108extern rtx_insn *insn;\n\
109extern rtx ins1;\n\
110extern rtx operands[];\n\
111\n\
112#endif /* gcc >= 3.0.1 */\n");
113}
114
115/* Write out one entry in the conditions table, using the data pointed
116   to by SLOT.  Each entry looks like this:
117
118   { "! optimize_size && ! TARGET_READ_MODIFY_WRITE",
119     __builtin_constant_p (! optimize_size && ! TARGET_READ_MODIFY_WRITE)
120     ? (int) (! optimize_size && ! TARGET_READ_MODIFY_WRITE)
121     : -1) },  */
122
123static int
124write_one_condition (void **slot, void * ARG_UNUSED (dummy))
125{
126  const struct c_test *test = * (const struct c_test **) slot;
127  const char *p;
128
129  rtx_reader_ptr->print_md_ptr_loc (test->expr);
130  fputs ("  { \"", stdout);
131  for (p = test->expr; *p; p++)
132    {
133      switch (*p)
134	{
135	case '\n': fputs ("\\n\\", stdout); break;
136	case '\\':
137	case '\"': putchar ('\\'); break;
138	default: break;
139	}
140      putchar (*p);
141    }
142
143  fputs ("\",\n    __builtin_constant_p ", stdout);
144  rtx_reader_ptr->print_c_condition (test->expr);
145  fputs ("\n    ? (int) ", stdout);
146  rtx_reader_ptr->print_c_condition (test->expr);
147  fputs ("\n    : -1 },\n", stdout);
148  return 1;
149}
150
151/* Write out the complete conditions table, its size, and a flag
152   indicating that gensupport.c can now do insn elision.  */
153static void
154write_conditions (void)
155{
156  puts ("\
157/* Structure definition duplicated from gensupport.h rather than\n\
158   drag in that file and its dependencies.  */\n\
159struct c_test\n\
160{\n\
161  const char *expr;\n\
162  int value;\n\
163};\n\
164\n\
165/* This table lists each condition found in the machine description.\n\
166   Each condition is mapped to its truth value (0 or 1), or -1 if that\n\
167   cannot be calculated at compile time.\n\
168   If we don't have __builtin_constant_p, or it's not acceptable in array\n\
169   initializers, fall back to assuming that all conditions potentially\n\
170   vary at run time.  It works in 3.0.1 and later; 3.0 only when not\n\
171   optimizing.  */\n\
172\n\
173#if GCC_VERSION >= 3001\n\
174static const struct c_test insn_conditions[] = {\n");
175
176  traverse_c_tests (write_one_condition, 0);
177
178  puts ("\n};\n#endif /* gcc >= 3.0.1 */\n");
179}
180
181/* Emit code which will convert the C-format table to a
182   (define_conditions) form, which the MD reader can understand.
183   The result will be added to the set of files scanned by
184   'downstream' generators.  */
185static void
186write_writer (void)
187{
188  puts ("int\n"
189	"main(void)\n"
190	"{\n"
191	"  unsigned int i;\n"
192        "  const char *p;\n"
193        "  puts (\"(define_conditions [\");\n"
194	"#if GCC_VERSION >= 3001\n"
195	"  for (i = 0; i < ARRAY_SIZE (insn_conditions); i++)\n"
196	"    {\n"
197	"      printf (\"  (%d \\\"\", insn_conditions[i].value);\n"
198	"      for (p = insn_conditions[i].expr; *p; p++)\n"
199	"        {\n"
200	"          switch (*p)\n"
201	"	     {\n"
202	"	     case '\\\\':\n"
203	"	     case '\\\"': putchar ('\\\\'); break;\n"
204	"	     default: break;\n"
205	"	     }\n"
206	"          putchar (*p);\n"
207	"        }\n"
208        "      puts (\"\\\")\");\n"
209        "    }\n"
210	"#endif /* gcc >= 3.0.1 */\n"
211	"  puts (\"])\");\n"
212        "  fflush (stdout);\n"
213        "return ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE;\n"
214	"}");
215}
216
217int
218main (int argc, const char **argv)
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  md_rtx_info info;
227  while (read_md_rtx (&info))
228    {
229      rtx def = info.def;
230      add_c_test (get_c_test (def), -1);
231      switch (GET_CODE (def))
232	{
233	case DEFINE_INSN:
234	case DEFINE_EXPAND:
235	  /* except.h needs to know whether there is an eh_return
236	     pattern in the machine description.  */
237	  if (!strcmp (XSTR (def, 0), "eh_return"))
238	    saw_eh_return = 1;
239	  break;
240
241	default:
242	  break;
243	}
244    }
245
246  write_header ();
247  write_conditions ();
248  write_writer ();
249
250  fflush (stdout);
251  return (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
252}
253