/* Build executable statement trees.
   Copyright (C) 2000, 2001, 2002, 2004, 2005, 2006, 2007, 2008
   Free Software Foundation, Inc.
   Contributed by Andy Vaught

This file is part of GCC.

GCC 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 3, or (at your option) any later
version.

GCC 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 GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

/* Executable statements are strung together into a singly linked list
   of code structures.  These structures are later translated into GCC
   GENERIC tree structures and from there to executable code for a
   target.  */

#include "config.h"
#include "system.h"
#include "gfortran.h"

gfc_code new_st;


/* Zeroes out the new_st structure.  */

void
gfc_clear_new_st (void)
{
  memset (&new_st, '\0', sizeof (new_st));
  new_st.op = EXEC_NOP;
}


/* Get a gfc_code structure.  */

gfc_code *
gfc_get_code (void)
{
  gfc_code *c;

  c = gfc_getmem (sizeof (gfc_code));
  c->loc = gfc_current_locus;
  return c;
}


/* Given some part of a gfc_code structure, append a set of code to
   its tail, returning a pointer to the new tail.  */

gfc_code *
gfc_append_code (gfc_code *tail, gfc_code *new)
{
  if (tail != NULL)
    {
      while (tail->next != NULL)
	tail = tail->next;

      tail->next = new;
    }

  while (new->next != NULL)
    new = new->next;

  return new;
}


/* Free a single code structure, but not the actual structure itself.  */

void
gfc_free_statement (gfc_code *p)
{
  if (p->expr)
    gfc_free_expr (p->expr);
  if (p->expr2)
    gfc_free_expr (p->expr2);

  switch (p->op)
    {
    case EXEC_NOP:
    case EXEC_ASSIGN:
    case EXEC_INIT_ASSIGN:
    case EXEC_GOTO:
    case EXEC_CYCLE:
    case EXEC_RETURN:
    case EXEC_IF:
    case EXEC_PAUSE:
    case EXEC_STOP:
    case EXEC_EXIT:
    case EXEC_WHERE:
    case EXEC_IOLENGTH:
    case EXEC_POINTER_ASSIGN:
    case EXEC_DO_WHILE:
    case EXEC_CONTINUE:
    case EXEC_TRANSFER:
    case EXEC_LABEL_ASSIGN:
    case EXEC_ENTRY:
    case EXEC_ARITHMETIC_IF:
      break;

    case EXEC_CALL:
    case EXEC_ASSIGN_CALL:
      gfc_free_actual_arglist (p->ext.actual);
      break;

    case EXEC_SELECT:
      if (p->ext.case_list)
	gfc_free_case_list (p->ext.case_list);
      break;

    case EXEC_DO:
      gfc_free_iterator (p->ext.iterator, 1);
      break;

    case EXEC_ALLOCATE:
    case EXEC_DEALLOCATE:
      gfc_free_alloc_list (p->ext.alloc_list);
      break;

    case EXEC_OPEN:
      gfc_free_open (p->ext.open);
      break;

    case EXEC_CLOSE:
      gfc_free_close (p->ext.close);
      break;

    case EXEC_BACKSPACE:
    case EXEC_ENDFILE:
    case EXEC_REWIND:
    case EXEC_FLUSH:
      gfc_free_filepos (p->ext.filepos);
      break;

    case EXEC_INQUIRE:
      gfc_free_inquire (p->ext.inquire);
      break;

    case EXEC_READ:
    case EXEC_WRITE:
      gfc_free_dt (p->ext.dt);
      break;

    case EXEC_DT_END:
      /* The ext.dt member is a duplicate pointer and doesn't need to
	 be freed.  */
      break;

    case EXEC_FORALL:
      gfc_free_forall_iterator (p->ext.forall_iterator);
      break;

    case EXEC_OMP_DO:
    case EXEC_OMP_END_SINGLE:
    case EXEC_OMP_PARALLEL:
    case EXEC_OMP_PARALLEL_DO:
    case EXEC_OMP_PARALLEL_SECTIONS:
    case EXEC_OMP_SECTIONS:
    case EXEC_OMP_SINGLE:
    case EXEC_OMP_WORKSHARE:
    case EXEC_OMP_PARALLEL_WORKSHARE:
      gfc_free_omp_clauses (p->ext.omp_clauses);
      break;

    case EXEC_OMP_CRITICAL:
      gfc_free (CONST_CAST (char *, p->ext.omp_name));
      break;

    case EXEC_OMP_FLUSH:
      gfc_free_namelist (p->ext.omp_namelist);
      break;

    case EXEC_OMP_ATOMIC:
    case EXEC_OMP_BARRIER:
    case EXEC_OMP_MASTER:
    case EXEC_OMP_ORDERED:
    case EXEC_OMP_END_NOWAIT:
      break;

    default:
      gfc_internal_error ("gfc_free_statement(): Bad statement");
    }
}


/* Free a code statement and all other code structures linked to it.  */

void
gfc_free_statements (gfc_code *p)
{
  gfc_code *q;

  for (; p; p = q)
    {
      q = p->next;

      if (p->block)
	gfc_free_statements (p->block);
      gfc_free_statement (p);
      gfc_free (p);
    }
}