gimplify.c

  /* We first do the main variant, then copy into any other variants.  */
  type = TYPE_MAIN_VARIANT (type);

  /* Avoid infinite recursion.  */
  if (TYPE_SIZES_GIMPLIFIED (type))
    return;

  TYPE_SIZES_GIMPLIFIED (type) = 1;

  switch (TREE_CODE (type))
    {
    case INTEGER_TYPE:
    case ENUMERAL_TYPE:
    case BOOLEAN_TYPE:
    case REAL_TYPE:
      gimplify_one_sizepos (&TYPE_MIN_VALUE (type), list_p);
      gimplify_one_sizepos (&TYPE_MAX_VALUE (type), list_p);

      for (t = TYPE_NEXT_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
	{
	  TYPE_MIN_VALUE (t) = TYPE_MIN_VALUE (type);
	  TYPE_MAX_VALUE (t) = TYPE_MAX_VALUE (type);
	}
      break;

    case ARRAY_TYPE:
      /* These types may not have declarations, so handle them here.  */
      gimplify_type_sizes (TREE_TYPE (type), list_p);
      gimplify_type_sizes (TYPE_DOMAIN (type), list_p);
      break;

    case RECORD_TYPE:
    case UNION_TYPE:
    case QUAL_UNION_TYPE:
      for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
	if (TREE_CODE (field) == FIELD_DECL)
	  {
	    gimplify_one_sizepos (&DECL_FIELD_OFFSET (field), list_p);
	    gimplify_type_sizes (TREE_TYPE (field), list_p);
	  }
      break;

    case POINTER_TYPE:
    case REFERENCE_TYPE:
	/* We used to recurse on the pointed-to type here, which turned out to
	   be incorrect because its definition might refer to variables not
	   yet initialized at this point if a forward declaration is involved.

	   It was actually useful for anonymous pointed-to types to ensure
	   that the sizes evaluation dominates every possible later use of the
	   values.  Restricting to such types here would be safe since there
	   is no possible forward declaration around, but would introduce an
	   undesirable middle-end semantic to anonymity.  We then defer to
	   front-ends the responsibility of ensuring that the sizes are
	   evaluated both early and late enough, e.g. by attaching artificial
	   type declarations to the tree.  */
      break;

    default:
      break;
    }

  gimplify_one_sizepos (&TYPE_SIZE (type), list_p);
  gimplify_one_sizepos (&TYPE_SIZE_UNIT (type), list_p);

  for (t = TYPE_NEXT_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
    {
      TYPE_SIZE (t) = TYPE_SIZE (type);
      TYPE_SIZE_UNIT (t) = TYPE_SIZE_UNIT (type);
      TYPE_SIZES_GIMPLIFIED (t) = 1;
    }
}

/* A subroutine of gimplify_type_sizes to make sure that *EXPR_P,
   a size or position, has had all of its SAVE_EXPRs evaluated.
   We add any required statements to STMT_P.  */

void
gimplify_one_sizepos (tree *expr_p, tree *stmt_p)
{
  tree type, expr = *expr_p;

  /* We don't do anything if the value isn't there, is constant, or contains
     A PLACEHOLDER_EXPR.  We also don't want to do anything if it's already
     a VAR_DECL.  If it's a VAR_DECL from another function, the gimplifier
     will want to replace it with a new variable, but that will cause problems
     if this type is from outside the function.  It's OK to have that here.  */
  if (expr == NULL_TREE || TREE_CONSTANT (expr)
      || TREE_CODE (expr) == VAR_DECL
      || CONTAINS_PLACEHOLDER_P (expr))
    return;

  type = TREE_TYPE (expr);
  *expr_p = unshare_expr (expr);

  gimplify_expr (expr_p, stmt_p, NULL, is_gimple_val, fb_rvalue);
  expr = *expr_p;

  /* Verify that we've an exact type match with the original expression.
     In particular, we do not wish to drop a "sizetype" in favour of a
     type of similar dimensions.  We don't want to pollute the generic
     type-stripping code with this knowledge because it doesn't matter
     for the bulk of GENERIC/GIMPLE.  It only matters that TYPE_SIZE_UNIT
     and friends retain their "sizetype-ness".  */
  if (TREE_TYPE (expr) != type
      && TREE_CODE (type) == INTEGER_TYPE
      && TYPE_IS_SIZETYPE (type))
    {
      tree tmp;

      *expr_p = create_tmp_var (type, NULL);
      tmp = build1 (NOP_EXPR, type, expr);
      tmp = build2 (MODIFY_EXPR, type, *expr_p, tmp);
      if (EXPR_HAS_LOCATION (expr))
	SET_EXPR_LOCUS (tmp, EXPR_LOCUS (expr));
      else
	SET_EXPR_LOCATION (tmp, input_location);

      gimplify_and_add (tmp, stmt_p);
    }
}

#ifdef ENABLE_CHECKING
/* Compare types A and B for a "close enough" match.  */

static bool
cpt_same_type (tree a, tree b)
{
  if (lang_hooks.types_compatible_p (a, b))
    return true;

  /* ??? The C++ FE decomposes METHOD_TYPES to FUNCTION_TYPES and doesn't
     link them together.  This routine is intended to catch type errors
     that will affect the optimizers, and the optimizers don't add new
     dereferences of function pointers, so ignore it.  */
  if ((TREE_CODE (a) == FUNCTION_TYPE || TREE_CODE (a) == METHOD_TYPE)
      && (TREE_CODE (b) == FUNCTION_TYPE || TREE_CODE (b) == METHOD_TYPE))
    return true;

  /* ??? The C FE pushes type qualifiers after the fact into the type of
     the element from the type of the array.  See build_unary_op's handling
     of ADDR_EXPR.  This seems wrong -- if we were going to do this, we
     should have done it when creating the variable in the first place.
     Alternately, why aren't the two array types made variants?  */
  if (TREE_CODE (a) == ARRAY_TYPE && TREE_CODE (b) == ARRAY_TYPE)
    return cpt_same_type (TREE_TYPE (a), TREE_TYPE (b));

  /* And because of those, we have to recurse down through pointers.  */
  if (POINTER_TYPE_P (a) && POINTER_TYPE_P (b))
    return cpt_same_type (TREE_TYPE (a), TREE_TYPE (b));

  return false;
}

/* Check for some cases of the front end missing cast expressions.
   The type of a dereference should correspond to the pointer type;
   similarly the type of an address should match its object.  */

static tree
check_pointer_types_r (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED,
		       void *data ATTRIBUTE_UNUSED)
{
  tree t = *tp;
  tree ptype, otype, dtype;

  switch (TREE_CODE (t))
    {
    case INDIRECT_REF:
    case ARRAY_REF:
      otype = TREE_TYPE (t);
      ptype = TREE_TYPE (TREE_OPERAND (t, 0));
      dtype = TREE_TYPE (ptype);
      gcc_assert (cpt_same_type (otype, dtype));
      break;

    case ADDR_EXPR:
      ptype = TREE_TYPE (t);
      otype = TREE_TYPE (TREE_OPERAND (t, 0));
      dtype = TREE_TYPE (ptype);
      if (!cpt_same_type (otype, dtype))
	{
	  /* &array is allowed to produce a pointer to the element, rather than
	     a pointer to the array type.  We must allow this in order to
	     properly represent assigning the address of an array in C into
	     pointer to the element type.  */
	  gcc_assert (TREE_CODE (otype) == ARRAY_TYPE
		      && POINTER_TYPE_P (ptype)
		      && cpt_same_type (TREE_TYPE (otype), dtype));
	  break;
	}
      break;

    default:
      return NULL_TREE;
    }


  return NULL_TREE;
}
#endif

/* Gimplify the body of statements pointed to by BODY_P.  FNDECL is the
   function decl containing BODY.  */

void
gimplify_body (tree *body_p, tree fndecl, bool do_parms)
{
  location_t saved_location = input_location;
  tree body, parm_stmts;

  timevar_push (TV_TREE_GIMPLIFY);

  gcc_assert (gimplify_ctxp == NULL);
  push_gimplify_context ();

  /* Unshare most shared trees in the body and in that of any nested functions.
     It would seem we don't have to do this for nested functions because
     they are supposed to be output and then the outer function gimplified
     first, but the g++ front end doesn't always do it that way.  */
  unshare_body (body_p, fndecl);
  unvisit_body (body_p, fndecl);

  /* Make sure input_location isn't set to something wierd.  */
  input_location = DECL_SOURCE_LOCATION (fndecl);

  /* Resolve callee-copies.  This has to be done before processing
     the body so that DECL_VALUE_EXPR gets processed correctly.  */
  parm_stmts = do_parms ? gimplify_parameters () : NULL;

  /* Gimplify the function's body.  */
  gimplify_stmt (body_p);
  body = *body_p;

  if (!body)
    body = alloc_stmt_list ();
  else if (TREE_CODE (body) == STATEMENT_LIST)
    {
      tree t = expr_only (*body_p);
      if (t)
	body = t;
    }

  /* If there isn't an outer BIND_EXPR, add one.  */
  if (TREE_CODE (body) != BIND_EXPR)
    {
      tree b = build3 (BIND_EXPR, void_type_node, NULL_TREE,
		       NULL_TREE, NULL_TREE);
      TREE_SIDE_EFFECTS (b) = 1;
      append_to_statement_list_force (body, &BIND_EXPR_BODY (b));
      body = b;
    }

  /* If we had callee-copies statements, insert them at the beginning
     of the function.  */
  if (parm_stmts)
    {
      append_to_statement_list_force (BIND_EXPR_BODY (body), &parm_stmts);
      BIND_EXPR_BODY (body) = parm_stmts;
    }

  /* Unshare again, in case gimplification was sloppy.  */
  unshare_all_trees (body);

  *body_p = body;

  pop_gimplify_context (body);
  gcc_assert (gimplify_ctxp == NULL);

#ifdef ENABLE_CHECKING
  walk_tree (body_p, check_pointer_types_r, NULL, NULL);
#endif

  timevar_pop (TV_TREE_GIMPLIFY);
  input_location = saved_location;
}

/* Entry point to the gimplification pass.  FNDECL is the FUNCTION_DECL
   node for the function we want to gimplify.  */

void
gimplify_function_tree (tree fndecl)
{
  tree oldfn, parm, ret;

  oldfn = current_function_decl;
  current_function_decl = fndecl;
  cfun = DECL_STRUCT_FUNCTION (fndecl);
  if (cfun == NULL)
    allocate_struct_function (fndecl);

  for (parm = DECL_ARGUMENTS (fndecl); parm ; parm = TREE_CHAIN (parm))
    {
      /* Preliminarily mark non-addressed complex variables as eligible
         for promotion to gimple registers.  We'll transform their uses
         as we find them.  */
      if (TREE_CODE (TREE_TYPE (parm)) == COMPLEX_TYPE
          && !TREE_THIS_VOLATILE (parm)
          && !needs_to_live_in_memory (parm))
        DECL_COMPLEX_GIMPLE_REG_P (parm) = 1;
    }

  ret = DECL_RESULT (fndecl);
  if (TREE_CODE (TREE_TYPE (ret)) == COMPLEX_TYPE
      && !needs_to_live_in_memory (ret))
    DECL_COMPLEX_GIMPLE_REG_P (ret) = 1;

  gimplify_body (&DECL_SAVED_TREE (fndecl), fndecl, true);

  /* If we're instrumenting function entry/exit, then prepend the call to
     the entry hook and wrap the whole function in a TRY_FINALLY_EXPR to
     catch the exit hook.  */
  /* ??? Add some way to ignore exceptions for this TFE.  */
  if (flag_instrument_function_entry_exit
      && ! DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (fndecl))
    {
      tree tf, x, bind;

      tf = build2 (TRY_FINALLY_EXPR, void_type_node, NULL, NULL);
      TREE_SIDE_EFFECTS (tf) = 1;
      x = DECL_SAVED_TREE (fndecl);
      append_to_statement_list (x, &TREE_OPERAND (tf, 0));
      x = implicit_built_in_decls[BUILT_IN_PROFILE_FUNC_EXIT];
      x = build_function_call_expr (x, NULL);
      append_to_statement_list (x, &TREE_OPERAND (tf, 1));

      bind = build3 (BIND_EXPR, void_type_node, NULL, NULL, NULL);
      TREE_SIDE_EFFECTS (bind) = 1;
      x = implicit_built_in_decls[BUILT_IN_PROFILE_FUNC_ENTER];
      x = build_function_call_expr (x, NULL);
      append_to_statement_list (x, &BIND_EXPR_BODY (bind));
      append_to_statement_list (tf, &BIND_EXPR_BODY (bind));

      DECL_SAVED_TREE (fndecl) = bind;
    }

  current_function_decl = oldfn;
  cfun = oldfn ? DECL_STRUCT_FUNCTION (oldfn) : NULL;
}


/* Expands EXPR to list of gimple statements STMTS.  If SIMPLE is true,
   force the result to be either ssa_name or an invariant, otherwise
   just force it to be a rhs expression.  If VAR is not NULL, make the
   base variable of the final destination be VAR if suitable.  */

tree
force_gimple_operand (tree expr, tree *stmts, bool simple, tree var)
{
  tree t;
  enum gimplify_status ret;
  gimple_predicate gimple_test_f;

  *stmts = NULL_TREE;

  if (is_gimple_val (expr))
    return expr;

  gimple_test_f = simple ? is_gimple_val : is_gimple_reg_rhs;

  push_gimplify_context ();
  gimplify_ctxp->into_ssa = in_ssa_p;

  if (var)
    expr = build2 (MODIFY_EXPR, TREE_TYPE (var), var, expr);

  ret = gimplify_expr (&expr, stmts, NULL,
		       gimple_test_f, fb_rvalue);
  gcc_assert (ret != GS_ERROR);

  if (referenced_vars)
    {
      for (t = gimplify_ctxp->temps; t ; t = TREE_CHAIN (t))
	add_referenced_var (t);
    }

  pop_gimplify_context (NULL);

  return expr;
}

/* Invokes force_gimple_operand for EXPR with parameters SIMPLE_P and VAR.  If
   some statements are produced, emits them before BSI.  */

tree
force_gimple_operand_bsi (block_stmt_iterator *bsi, tree expr,
			  bool simple_p, tree var)
{
  tree stmts;

  expr = force_gimple_operand (expr, &stmts, simple_p, var);
  if (stmts)
    bsi_insert_before (bsi, stmts, BSI_SAME_STMT);

  return expr;
}

#include "gt-gimplify.h"