/* Generate code from machine description to emit insns as rtl.   Copyright (C) 1987,1988 Free Software Foundation, Inc.This file is part of GNU CC.GNU CC is free software; you can redistribute it and/or modifyit under the terms of the GNU General Public License as published bythe Free Software Foundation; either version 1, 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 ofMERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See theGNU General Public License for more details.You should have received a copy of the GNU General Public Licensealong with GNU CC; see the file COPYING.  If not, write tothe Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  *//* This program is used to produce insn-recog.c, which contains   a function called `recog' plus its subroutines.   These functions contain a decision tree   that recognizes whether an rtx, the argument given to recog,   is a valid instruction.   recog returns -1 if the rtx is not valid.   If the rtx is valid, recog returns a nonnegative number   which is the insn code number for the pattern that matched.   This is the same as the order in the machine description of the   entry that matched.  This number can be used as an index into   insn_templates and insn_n_operands (found in insn-output.c)   or as an argument to output_insn_hairy (also in insn-output.c).  */#include <stdio.h>#include "config.h"#include "rtl.h"#include "obstack.h"struct obstack obstack;struct obstack *rtl_obstack = &obstack;#define obstack_chunk_alloc xmalloc#define obstack_chunk_free freeextern int xmalloc ();extern void free ();/* Data structure for decision tree for recognizing   legitimate instructions.  */struct decision{  int number;  char *position;  RTX_CODE code;  char *exact;  enum machine_mode mode;  char *tests;  int insn_code_number;  struct decision *next;  struct decision *success;  int opno;  int dupno;  int dupcount;  int test_elt_zero_int;  int elt_zero_int;  int test_elt_one_int;  int elt_one_int;  int ignmode;  struct decision *afterward;  int label_needed;  char *c_test;  char *reg_class;  char enforce_mode;  int veclen;  int subroutine_number;};#define SUBROUTINE_THRESHOLD 50int next_subroutine_number;/*recognize (top){ staten:  x = XVECEXP (top, 0, 3);  if (test_code (GET_CODE (x))      && test_mode (MODE (x))      && whatever_else)    goto statep;  else if (next one...)    goto statem:  goto stater; statep:  actions...;  return 1; statem:  x = stack[depth--];  more tests...; stateq:  stack[++depth] = x;  x = XEXP (stack[depth], 0);  more tests...; stater:  x = XEXP (stack[depth], 1);}*/int next_number;int next_insn_code;/* Number of MATCH_DUP's seen so far in this instruction.  */int dupcount;struct decision *add_to_sequence ();struct decision *try_merge_2 ();void write_subroutine ();void print_code ();void clear_codes ();void clear_modes ();void change_state ();void write_tree ();char *copystr ();char *concat ();void fatal ();void fancy_abort ();void mybzero ();struct decision *first;/* Construct and return a sequence of decisions   that will recognize INSN.  */struct decision *make_insn_sequence (insn)     rtx insn;{  rtx x;  char *c_test = XSTR (insn, 2);  struct decision *last;  dupcount = 0;  if (XVECLEN (insn, 1) == 1)    x = XVECEXP (insn, 1, 0);  else    {      x = rtx_alloc (PARALLEL);      XVEC (x, 0) = XVEC (insn, 1);      PUT_MODE (x, VOIDmode);    }  last = add_to_sequence (x, 0, "");  if (c_test[0])    last->c_test = c_test;  last->insn_code_number = next_insn_code++;  return first;}struct decision *add_to_sequence (pattern, last, position)     rtx pattern;     struct decision *last;     char *position;{  register RTX_CODE code;  register struct decision *new    = (struct decision *) xmalloc (sizeof (struct decision));  struct decision *this;  char *newpos;  register char *fmt;  register int i;  int depth;  int len;  new->number = next_number++;  new->position = copystr (position);  new->exact = 0;  new->next = 0;  new->success = 0;  new->insn_code_number = -1;  new->tests = 0;  new->opno = -1;  new->dupno = -1;  new->dupcount = -1;  new->test_elt_zero_int = 0;  new->test_elt_one_int = 0;  new->elt_zero_int = 0;  new->elt_one_int = 0;  new->enforce_mode = 0;  new->ignmode = 0;  new->afterward = 0;  new->label_needed = 0;  new->c_test = 0;  new->reg_class = 0;  new->veclen = 0;  new->subroutine_number = 0;  this = new;  if (last == 0)    first = new;  else    last->success = new;  depth = strlen (position);  newpos = (char *) alloca (depth + 2);  strcpy (newpos, position);  newpos[depth + 1] = 0; restart:  if (pattern == 0)    {      new->exact = "0";      new->code = UNKNOWN;      new->mode = VOIDmode;      return new;    }  switch (GET_MODE (pattern))    {    case 0:      new->mode = VOIDmode;      break;    default:      new->mode = GET_MODE (pattern);      break;    }  new->code = code = GET_CODE (pattern);  switch (code)    {    case MATCH_OPERAND:      new->opno = XINT (pattern, 0);      new->code = UNKNOWN;      new->tests = XSTR (pattern, 1);      if (*new->tests == 0)	new->tests = 0;      new->reg_class = XSTR (pattern, 2);      if (*new->reg_class == 0)	new->reg_class = 0;      return new;    case MATCH_OPERATOR:      new->opno = XINT (pattern, 0);      new->code = UNKNOWN;      new->tests = XSTR (pattern, 1);      if (*new->tests == 0)	new->tests = 0;      for (i = 0; i < XVECLEN (pattern, 2); i++)	{	  newpos[depth] = i + '0';	  new = add_to_sequence (XVECEXP (pattern, 2, i), new, newpos);	}      this->success->enforce_mode = 0;      return new;    case MATCH_DUP:      new->dupno = XINT (pattern, 0);      new->dupcount = dupcount++;      new->code = UNKNOWN;      return new;    case ADDRESS:      pattern = XEXP (pattern, 0);      goto restart;    case PC:      new->exact = "pc_rtx";      return new;    case CC0:      new->exact = "cc0_rtx";      return new;    case CONST_INT:      if (INTVAL (pattern) == 0)	{	  new->exact = "const0_rtx";	  return new;	}      if (INTVAL (pattern) == 1)	{	  new->exact = "const1_rtx";	  return new;	}      break;    case SET:      newpos[depth] = '0';      new = add_to_sequence (SET_DEST (pattern), new, newpos);      this->success->enforce_mode = 1;      newpos[depth] = '1';      new = add_to_sequence (SET_SRC (pattern), new, newpos);      return new;    case STRICT_LOW_PART:      newpos[depth] = '0';      new = add_to_sequence (XEXP (pattern, 0), new, newpos);      this->success->enforce_mode = 1;      return new;    case SUBREG:      this->test_elt_one_int = 1;      this->elt_one_int = XINT (pattern, 1);      newpos[depth] = '0';      new = add_to_sequence (XEXP (pattern, 0), new, newpos);      this->success->enforce_mode = 1;      return new;    case ZERO_EXTRACT:    case SIGN_EXTRACT:      newpos[depth] = '0';      new = add_to_sequence (XEXP (pattern, 0), new, newpos);      this->success->enforce_mode = 1;      newpos[depth] = '1';      new = add_to_sequence (XEXP (pattern, 1), new, newpos);      newpos[depth] = '2';      new = add_to_sequence (XEXP (pattern, 2), new, newpos);      return new;    }  fmt = GET_RTX_FORMAT (code);  len = GET_RTX_LENGTH (code);  for (i = 0; i < len; i++)    {      newpos[depth] = '0' + i;      if (fmt[i] == 'e' || fmt[i] == 'u')	new = add_to_sequence (XEXP (pattern, i), new, newpos);      else if (fmt[i] == 'i' && i == 0)	{	  this->test_elt_zero_int = 1;	  this->elt_zero_int = XINT (pattern, i);	}      else if (fmt[i] == 'i' && i == 1)	{	  this->test_elt_one_int = 1;	  this->elt_one_int = XINT (pattern, i);	}      else if (fmt[i] == 'E')	{	  register int j;	  /* We do not handle a vector appearing as other than	     the first item, just because nothing uses them	     and by handling only the special case	     we can use one element in newpos for either	     the item number of a subexpression	     or the element number in a vector.  */	  if (i != 0)	    abort ();	  this->veclen = XVECLEN (pattern, i);	  for (j = 0; j < XVECLEN (pattern, i); j++)	    {	      newpos[depth] = 'a' + j;	      new = add_to_sequence (XVECEXP (pattern, i, j),				     new, newpos);	    }	}      else if (fmt[i] != '0')	abort ();    }  return new;}/* Merge two decision trees OLD and ADD,   modifying OLD destructively,   and return the merged tree.  */struct decision *merge_trees (old, add)     register struct decision *old, *add;{  while (add)    {      register struct decision *next = add->next;      add->next = 0;      if (!try_merge_1 (old, add))	old = try_merge_2 (old, add);      add = next;    }  return old;}/* Merge ADD into the next-chain starting with OLD   only if it overlaps a condition already tested in OLD.   Returns 1 if successful (OLD is modified),   0 if nothing has been done.  */inttry_merge_1 (old, add)     register struct decision *old, *add;{  while (old)    {      if ((old->position == add->position	   || (old->position && add->position	       && !strcmp (old->position, add->position)))	  && (old->tests == add->tests	      || (old->tests && add->tests && !strcmp (old->tests, add->tests)))	  && (old->c_test == add->c_test	      || (old->c_test && add->c_test && !strcmp (old->c_test, add->c_test)))	  && old->test_elt_zero_int == add->test_elt_zero_int	  && old->elt_zero_int == add->elt_zero_int	  && old->test_elt_one_int == add->test_elt_one_int	  && old->elt_one_int == add->elt_one_int	  && old->veclen == add->veclen	  && old->dupno == add->dupno	  && old->opno == add->opno	  && (old->tests == 0	      || (add->enforce_mode ? no_same_mode (old) : old->next == 0))	  && old->code == add->code	  && old->mode == add->mode)	{	  old->success = merge_trees (old->success, add->success);	  if (old->insn_code_number >= 0 && add->insn_code_number >= 0)	    fatal ("Two actions at one point in tree.");	  if (old->insn_code_number == -1)	    old->insn_code_number = add->insn_code_number;	  return 1;	}      old = old->next;    }  return 0;}/* Merge ADD into the next-chain that starts with OLD,   preferably after something that tests the same place   that ADD does.   The next-chain of ADD itself is ignored, and it is set   up for entering ADD into the new chain.   Returns the new chain.  */struct decision *try_merge_2 (old, add)     struct decision *old, *add;{  register struct decision *p;  struct decision *last = 0;  struct decision *last_same_place = 0;  /* Put this in after the others that test the same place,     if there are any.  If not, find the last chain element     and insert there.     One modification: if this one is NOT a MATCH_OPERAND,     put it before any MATCH_OPERANDS that test the same place.     Another: if enforce_mode (i.e. this is first operand of a SET),     put this after the last thing that tests the same place for     the same mode.  */  int operand = 0 != add->tests;  for (p = old; p; p = p->next)    {      if (p->position == add->position	  || (p->position && add->position	      && !strcmp (p->position, add->position)))	{	  last_same_place = p;	  /* If enforce_mode, segregate the modes in numerical order.  */	  if (p->enforce_mode && (int) add->mode < (int) p->mode)	    break;#if 0	  /* Keep explicit decompositions before those that test predicates.	     If enforce_mode, do this separately within each mode.  */	  if (! p->enforce_mode || p->mode == add->mode)	    if (!operand && p->tests)	      break;#endif	}      /* If this is past the end of the decisions at the same place as ADD,	 stop looking now; add ADD before here.  */      else if (last_same_place)	break;      last = p;    }  /* Insert before P, which means after LAST.  */  if (last)    {      add->next = last->next;      last->next = add;      return old;    }  add->next = old;  return add;}intno_same_mode (node)     struct decision *node;{  register struct decision *p;  register enum machine_mode mode = node->mode;  for (p = node->next; p; p = p->next)    if (p->mode == mode)      return 0;  return 1;}/* Count the number of subnodes of node NODE, assumed to be the start   of a next-chain.  If the number is high enough, make NODE start   a separate subroutine in the C code that is generated.  */intbreak_out_subroutines (node)     struct decision *node;{  int size = 0;  struct decision *sub;  for (sub = node; sub; sub = sub->next)    size += 1 + break_out_subroutines (sub->success);  if (size > SUBROUTINE_THRESHOLD)    {      node->subroutine_number = ++next_subroutine_number;      write_subroutine (node);      size = 1;    }  return size;}voidwrite_subroutine (tree)     struct decision *tree;{  printf ("int\nrecog_%d (x0, insn)\n     register rtx x0;\n     rtx insn;\n{\n",	  tree->subroutine_number);  printf ("  register rtx x1, x2, x3, x4, x5;\n  rtx x6, x7, x8, x9, x10, x11;\n");  printf ("  int tem;\n");  write_tree (tree, "", 0, "", 1);  printf (" ret0: return -1;\n}\n\n");