* gensupport.c: Include hashtab.h.

	(insn_elision, condition_table, hash_c_test, cmp_c_test,
	maybe_eval_c_test): New routines and data structures to
	support insn elision.
	(init_md_reader): Read and initialize the condition_table.
	(read_md_rtx): Discard insn patterns whose C test is provably
	always false.
	* gensupport.h: Declare new functions and data structures.

	* genconditions.c, dummy-conditions.c: New files.
	* Makefile.in: Build genconditions; run it to construct
	insn-conditions.c; build that and link it into most gen*
	programs.
	(HOST_SUPPORT, HOST_EARLY_SUPPORT): New variables.
	(GEN): Delete, unused.
	(STAGESTUFF): Update.

	* gencodes.c: (gen_insn): #define CODE_FOR_xxx equal to
	CODE_FOR_nothing for all elided patterns.
	(main): Tweaked to support this.
	* genflags.c (gen_proto): Emit a static inline generator
	function here for all elided patterns, which simply returns
	NULL_RTX.
	(gen_insn): Do not define HAVE_xxx for elided patterns.
	(main): Tweaked to support this.  No need to forward-declare
	struct rtx_def.
	* genrecog.c: Do not bother emitting the C test if it's known
	to be true at compile time.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@55839 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 240 insertions, 0 deletions

diff --git a/gcc/genconditions.c b/gcc/genconditions.c
new file mode 100644
index 00000000000..02f80ee478d
--- /dev/null
+++ b/gcc/genconditions.c
@@ -0,0 +1,240 @@
+/* Process machine description and calculate constant conditions.
+   Copyright (C) 2001, 2002 Free Software Foundation, Inc.
+
+   This file is part of GNU CC.
+
+   GNU CC is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   GNU CC is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with GNU CC; see the file COPYING.  If not, write to
+   the Free Software Foundation, 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+/* In a machine description, all of the insn patterns - define_insn,
+   define_expand, define_split, define_peephole, define_peephole2 -
+   contain an optional C expression which makes the final decision
+   about whether or not this pattern is usable.  That expression may
+   turn out to be always false when the compiler is built.  If it is,
+   most of the programs that generate code from the machine
+   description can simply ignore the entire pattern.  */
+
+#include "hconfig.h"
+#include "system.h"
+#include "rtl.h"
+#include "errors.h"
+#include "hashtab.h"
+#include "gensupport.h"
+
+/* so we can include except.h in the generated file */
+static int saw_eh_return;
+
+static htab_t condition_table;
+
+static void add_condition	PARAMS ((const char *));
+static void write_header	PARAMS ((void));
+static void write_conditions	PARAMS ((void));
+static int write_one_condition	PARAMS ((PTR *, PTR));
+
+extern int main			PARAMS ((int, char **));
+
+/* Record the C test expression EXPR in the condition_table.
+   Duplicates clobber previous entries, which leaks memory, but
+   we don't care for this application.  */
+
+static void
+add_condition (expr)
+     const char *expr;
+{
+  struct c_test *test;
+
+  if (expr[0] == 0)
+    return;
+
+  test = (struct c_test *) xmalloc (sizeof (struct c_test));
+  test->expr = expr;
+
+  *(htab_find_slot (condition_table, test, INSERT)) = test;
+}
+
+/* Generate the header for insn-conditions.c.  */
+
+static void
+write_header ()
+{
+  puts ("\
+/* Generated automatically by the program `genconditions' from the target\n\
+   machine description file.  */\n\
+\n\
+#include \"hconfig.h\"\n\
+#include \"insn-constants.h\"\n");
+
+  puts ("\
+/* Do not allow checking to confuse the issue.  */\n\
+#undef ENABLE_CHECKING\n\
+#undef ENABLE_TREE_CHECKING\n\
+#undef ENABLE_RTL_CHECKING\n\
+#undef ENABLE_RTL_FLAG_CHECKING\n\
+#undef ENABLE_GC_CHECKING\n\
+#undef ENABLE_GC_ALWAYS_COLLECT\n");
+
+  puts ("\
+#include \"system.h\"\n\
+#include \"rtl.h\"\n\
+#include \"tm_p.h\"\n\
+#include \"function.h\"\n");
+
+  puts ("\
+/* Fake - insn-config.h doesn't exist yet.  */\n\
+#define MAX_RECOG_OPERANDS 10\n\
+#define MAX_DUP_OPERANDS 10\n\
+#define MAX_INSNS_PER_SPLIT 5\n");
+
+  puts ("\
+#include \"regs.h\"\n\
+#include \"recog.h\"\n\
+#include \"real.h\"\n\
+#include \"output.h\"\n\
+#include \"flags.h\"\n\
+#include \"hard-reg-set.h\"\n\
+#include \"resource.h\"\n\
+#include \"toplev.h\"\n\
+#include \"reload.h\"\n\
+#include \"gensupport.h\"\n");
+
+  if (saw_eh_return)
+    puts ("#define HAVE_eh_return 1");
+  puts ("#include \"except.h\"\n");
+
+  puts ("\
+/* Dummy external declarations.  */\n\
+extern rtx insn;\n\
+extern rtx ins1;\n\
+extern rtx operands[];\n\
+extern int next_insn_tests_no_inequality PARAMS ((rtx));\n");
+
+  puts ("\
+/* If we don't have __builtin_constant_p, or it's not acceptable in\n\
+   array initializers, fall back to assuming that all conditions\n\
+   potentially vary at run time.  It works in 3.0.1 and later; 3.0\n\
+   only when not optimizing.  */\n\
+#if (GCC_VERSION >= 3001) || ((GCC_VERSION == 3000) && !__OPTIMIZE__)\n\
+# define MAYBE_EVAL(expr) (__builtin_constant_p(expr) ? (int) (expr) : -1)\n\
+#else\n\
+# define MAYBE_EVAL(expr) -1\n\
+#endif\n");
+}
+
+/* Write out one entry in the conditions table, using the data pointed
+   to by SLOT.  Each entry looks like this:
+  { "! optimize_size && ! TARGET_READ_MODIFY_WRITE",
+    MAYBE_EVAL (! optimize_size && ! TARGET_READ_MODIFY_WRITE) },  */
+
+static int
+write_one_condition (slot, dummy)
+     PTR *slot;
+     PTR dummy ATTRIBUTE_UNUSED;
+{
+  const struct c_test *test = * (const struct c_test **) slot;
+  const char *p;
+
+  fputs ("  { \"", stdout);
+  for (p = test->expr; *p; p++)
+    {
+      if (*p == '\n')
+	fputs ("\\n\\\n", stdout);
+      else if (*p == '"')
+	fputs ("\\\"", stdout);
+      else
+	putchar (*p);
+    }
+
+  printf ("\",\n    MAYBE_EVAL (%s) },\n", test->expr);
+  return 1;
+}
+
+/* Write out the complete conditions table, its size, and a flag
+   indicating that gensupport.c can now do insn elision.  */
+static void
+write_conditions ()
+{
+  puts ("\
+/* This table lists each condition found in the machine description.\n\
+   Each condition is mapped to its truth value (0 or 1), or -1 if that\n\
+   cannot be calculated at compile time. */\n\
+\n\
+const struct c_test insn_conditions[] = {");
+
+  htab_traverse (condition_table, write_one_condition, 0);
+
+  puts ("};\n");
+
+  printf ("const size_t n_insn_conditions = %lu;\n",
+	  (unsigned long) htab_elements (condition_table));
+  puts ("const int insn_elision_unavailable = 0;");
+}
+
+int
+main (argc, argv)
+     int argc;
+     char **argv;
+{
+  rtx desc;
+  int pattern_lineno; /* not used */
+  int code;
+
+  progname = "genconditions";
+
+  if (argc <= 1)
+    fatal ("No input file name.");
+
+  if (init_md_reader (argv[1]) != SUCCESS_EXIT_CODE)
+    return (FATAL_EXIT_CODE);
+
+  condition_table = htab_create (1000, hash_c_test, cmp_c_test, NULL);
+
+  /* Read the machine description.  */
+
+  while (1)
+    {
+      desc = read_md_rtx (&pattern_lineno, &code);
+      if (desc == NULL)
+	break;
+
+      /* N.B. define_insn_and_split, define_cond_exec are handled
+	 entirely within read_md_rtx; we never see them.  */
+      switch (GET_CODE (desc))
+	{
+	default:
+	  break;
+
+	case DEFINE_INSN:
+	case DEFINE_EXPAND:
+	  add_condition (XSTR (desc, 2));
+	  /* except.h needs to know whether there is an eh_return
+	     pattern in the machine description.  */
+	  if (!strcmp (XSTR (desc, 0), "eh_return"))
+	    saw_eh_return = 1;
+	  break;
+
+	case DEFINE_SPLIT:
+	case DEFINE_PEEPHOLE:
+	case DEFINE_PEEPHOLE2:
+	  add_condition (XSTR (desc, 1));
+	  break;
+	}
+    }
+
+  write_header ();
+  write_conditions ();
+
+  fflush (stdout);
+  return (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
+}