static tree
build_equiv_decl (tree union_type, bool is_init)
{
  tree decl;
  char name[15];
  static int serial = 0;

  if (is_init)
    {
      decl = gfc_create_var (union_type, "equiv");
      TREE_STATIC (decl) = 1;
      return decl;
    }

  snprintf (name, sizeof (name), "equiv.%d", serial++);
  decl = build_decl (VAR_DECL, get_identifier (name), union_type);
  DECL_ARTIFICIAL (decl) = 1;
  DECL_IGNORED_P (decl) = 1;

  if (!gfc_can_put_var_on_stack (DECL_SIZE_UNIT (decl)))
    TREE_STATIC (decl) = 1;

  TREE_ADDRESSABLE (decl) = 1;
  TREE_USED (decl) = 1;

  /* The source location has been lost, and doesn't really matter.
     We need to set it to something though.  */
  gfc_set_decl_location (decl, &gfc_current_locus);

  gfc_add_decl_to_function (decl);

  return decl;
}

static tree
build_equiv_decl (tree union_type, bool is_init)
{
  tree decl;

  if (is_init)
    {
      decl = gfc_create_var (union_type, "equiv");
      TREE_STATIC (decl) = 1;
      return decl;
    }

  decl = build_decl (VAR_DECL, NULL, union_type);
  DECL_ARTIFICIAL (decl) = 1;

  DECL_COMMON (decl) = 1;

  TREE_ADDRESSABLE (decl) = 1;
  TREE_USED (decl) = 1;

  /* The source location has been lost, and doesn't really matter.
     We need to set it to something though.  */
  gfc_set_decl_location (decl, &gfc_current_locus);

  gfc_add_decl_to_function (decl);

  return decl;
}

static tree
make_fname_decl ()
{
    const char *name = lang_hooks.decl_printable_name (current_function_decl, 0);
    tree decl, type, init;
    size_t length = strlen (name);

    type = build_array_type (build_type_variant (char_type_node, true, false),
                             build_index_type (size_int (length)));

    decl = build_decl (UNKNOWN_LOCATION, VAR_DECL,
                       get_identifier ("__function_name__"), type);

    TREE_STATIC (decl) = 1;
    TREE_READONLY (decl) = 1;
    DECL_ARTIFICIAL (decl) = 1;

    init = build_string (length + 1, name);
    TREE_TYPE (init) = type;
    TREE_READONLY (init) = 1;
    DECL_READ_P (decl) = 1;
    DECL_INITIAL (decl) = init;

    TREE_USED (decl) = 1;
    TREE_ADDRESSABLE (decl) = 1;
    DECL_CONTEXT (decl) = current_function_decl;

    return decl;
}

static void
build_field (segment_info *h, tree union_type, record_layout_info rli)
{
  tree field;
  tree name;
  HOST_WIDE_INT offset = h->offset;
  unsigned HOST_WIDE_INT desired_align, known_align;

  name = get_identifier (h->sym->name);
  field = build_decl (FIELD_DECL, name, h->field);
  gfc_set_decl_location (field, &h->sym->declared_at);
  known_align = (offset & -offset) * BITS_PER_UNIT;
  if (known_align == 0 || known_align > BIGGEST_ALIGNMENT)
    known_align = BIGGEST_ALIGNMENT;

  desired_align = update_alignment_for_field (rli, field, known_align);
  if (desired_align > known_align)
    DECL_PACKED (field) = 1;

  DECL_FIELD_CONTEXT (field) = union_type;
  DECL_FIELD_OFFSET (field) = size_int (offset);
  DECL_FIELD_BIT_OFFSET (field) = bitsize_zero_node;
  SET_DECL_OFFSET_ALIGN (field, known_align);

  rli->offset = size_binop (MAX_EXPR, rli->offset,
                            size_binop (PLUS_EXPR,
                                        DECL_FIELD_OFFSET (field),
                                        DECL_SIZE_UNIT (field)));
  h->field = field;
}

static tree
create_struct_type(tree decl, size_t front_rz_size, size_t rear_rz_size)
{
    // TODO make this dynamic rather than static
    char type_name[50];
    tree fieldfront, orig_var, fieldrear, struct_type;

    gcc_assert(front_rz_size % 8 == 0 && rear_rz_size % 8 == 0);

    struct_type = mf_mark(make_node (RECORD_TYPE));

    // Build the front red zone
    tree front_array_idx =  build_index_type (size_int (front_rz_size / sizeof(unsigned int)));
    tree front_rz_array = build_array_type (unsigned_type_node, front_array_idx);
    fieldfront = build_decl (UNKNOWN_LOCATION,
            FIELD_DECL, get_identifier ("rz_front"), front_rz_array);
    DECL_ALIGN(fieldfront) = 8;
    DECL_CONTEXT (fieldfront) = struct_type;

    // orig variable
    orig_var = build_decl (UNKNOWN_LOCATION,
            FIELD_DECL, get_identifier("orig_var"), TREE_TYPE(decl));
    DECL_CONTEXT (orig_var) = struct_type; // Look at comments above
    DECL_CHAIN (fieldfront) = orig_var;

    // Rear zone
    if (COMPLETE_TYPE_P(decl)){
        tree rear_array_idx =  build_index_type (size_int (rear_rz_size / sizeof(unsigned int)));
        tree rear_rz_array = build_array_type (unsigned_type_node, rear_array_idx);
        fieldrear = build_decl (UNKNOWN_LOCATION,
                FIELD_DECL, get_identifier ("rz_rear"), rear_rz_array);
        DECL_ALIGN(fieldrear) = 8;
        DECL_CONTEXT (fieldrear) = struct_type;
        DECL_CHAIN (orig_var) = fieldrear;
    }

    TYPE_FIELDS (struct_type) = fieldfront;

    strcpy(type_name, "rz_");
    strcat(type_name, get_name(decl));
    strcat(type_name, "_type");
    TYPE_NAME (struct_type) = get_identifier (type_name);
    layout_type (struct_type);

    return struct_type;
}

static tree
add_field (const char *name, tree type, tree fields)
{
  tree t = get_identifier (name);
  tree field = build_decl (BUILTINS_LOCATION, FIELD_DECL, t, type);
  TREE_CHAIN (field) = fields;
  return field;
}

static tree
create_cilk_helper_decl (struct wrapper_data *wd)
{
  char name[20];
  if (wd->type == CILK_BLOCK_FOR)
    sprintf (name, "_cilk_for_" HOST_WIDE_INT_PRINT_DEC, cilk_wrapper_count++);
  else if (wd->type == CILK_BLOCK_SPAWN)
    sprintf (name, "_cilk_spn_" HOST_WIDE_INT_PRINT_DEC, cilk_wrapper_count++);
  else
    gcc_unreachable (); 
  
  clean_symbol_name (name);

  tree fndecl = build_decl (DECL_SOURCE_LOCATION (current_function_decl),
			    FUNCTION_DECL, get_identifier (name), wd->fntype);

  TREE_PUBLIC (fndecl) = 0;
  TREE_STATIC (fndecl) = 1;
  TREE_USED (fndecl) = 1;
  DECL_ARTIFICIAL (fndecl) = 0;
  DECL_IGNORED_P (fndecl) = 0;
  DECL_EXTERNAL (fndecl) = 0;

  DECL_CONTEXT (fndecl) = wd->context; 
  tree block = make_node (BLOCK);
  DECL_INITIAL (fndecl) = block;
  TREE_USED (block) = 1;
  BLOCK_SUPERCONTEXT (block) = fndecl;
  gcc_assert (!DECL_SAVED_TREE (fndecl));

  /* Inlining would defeat the purpose of this wrapper.
     Either it secretly switches stack frames or it allocates
     a stable stack frame to hold function arguments even if
     the parent stack frame is stolen.  */
  DECL_UNINLINABLE (fndecl) = 1;

  tree result_decl = build_decl (UNKNOWN_LOCATION, RESULT_DECL, NULL_TREE, 
				 void_type_node);
  DECL_ARTIFICIAL (result_decl) = 0;
  DECL_IGNORED_P (result_decl) = 1;
  DECL_CONTEXT (result_decl) = fndecl;
  DECL_RESULT (fndecl) = result_decl;
  
  return fndecl;
}

/* Helper for mudflap_init: construct a decl with the given category,
   name, and type, mark it an external reference, and pushdecl it.  */
static inline tree
mf_make_builtin (enum tree_code category, const char *name, tree type)
{
  tree decl = mf_mark (build_decl (category, get_identifier (name), type));
  TREE_PUBLIC (decl) = 1;
  DECL_EXTERNAL (decl) = 1;
  lang_hooks.decls.pushdecl (decl);
  return decl;
}

/* Helper for mudflap_init: construct a tree corresponding to the type
     struct __mf_cache { uintptr_t low; uintptr_t high; };
     where uintptr_t is the FIELD_TYPE argument.  */
static inline tree
mf_make_mf_cache_struct_type (tree field_type)
{
  /* There is, abominably, no language-independent way to construct a
     RECORD_TYPE.  So we have to call the basic type construction
     primitives by hand.  */
  tree fieldlo = build_decl (FIELD_DECL, get_identifier ("low"), field_type);
  tree fieldhi = build_decl (FIELD_DECL, get_identifier ("high"), field_type);

  tree struct_type = make_node (RECORD_TYPE);
  DECL_CONTEXT (fieldlo) = struct_type;
  DECL_CONTEXT (fieldhi) = struct_type;
  TREE_CHAIN (fieldlo) = fieldhi;
  TYPE_FIELDS (struct_type) = fieldlo;
  TYPE_NAME (struct_type) = get_identifier ("__mf_cache");
  layout_type (struct_type);

  return struct_type;
}

static void start_unit_callback (void *gcc_data, void *user_data)
{
  if (integer_type_node) {
    fake_var = build_decl (VAR_DECL, 
                           get_identifier ("_fake_var_"),
                           integer_type_node);
    TREE_PUBLIC (fake_var) = 1;
    DECL_ARTIFICIAL (fake_var) = 1;
  }
}

/* Add code:
   __thread gcov*	__gcov_indirect_call_counters; // pointer to actual counter
   __thread void*	__gcov_indirect_call_callee; // actual callee address
   __thread int __gcov_function_counter; // time profiler function counter
*/
static void
init_ic_make_global_vars (void)
{
  tree  gcov_type_ptr;

  ptr_void = build_pointer_type (void_type_node);

  ic_void_ptr_var
    = build_decl (UNKNOWN_LOCATION, VAR_DECL,
		  get_identifier (
			  (PARAM_VALUE (PARAM_INDIR_CALL_TOPN_PROFILE) ?
			   "__gcov_indirect_call_topn_callee" :
			   "__gcov_indirect_call_callee")),
		  ptr_void);
  TREE_PUBLIC (ic_void_ptr_var) = 1;
  DECL_EXTERNAL (ic_void_ptr_var) = 1;
  TREE_STATIC (ic_void_ptr_var) = 1;
  DECL_ARTIFICIAL (ic_void_ptr_var) = 1;
  DECL_INITIAL (ic_void_ptr_var) = NULL;
  if (targetm.have_tls)
    set_decl_tls_model (ic_void_ptr_var, decl_default_tls_model (ic_void_ptr_var));

  varpool_node::finalize_decl (ic_void_ptr_var);

  gcov_type_ptr = build_pointer_type (get_gcov_type ());

  ic_gcov_type_ptr_var
    = build_decl (UNKNOWN_LOCATION, VAR_DECL,
		  get_identifier (
			  (PARAM_VALUE (PARAM_INDIR_CALL_TOPN_PROFILE) ?
			   "__gcov_indirect_call_topn_counters" :
			   "__gcov_indirect_call_counters")),
		  gcov_type_ptr);
  TREE_PUBLIC (ic_gcov_type_ptr_var) = 1;
  DECL_EXTERNAL (ic_gcov_type_ptr_var) = 1;
  TREE_STATIC (ic_gcov_type_ptr_var) = 1;
  DECL_ARTIFICIAL (ic_gcov_type_ptr_var) = 1;
  DECL_INITIAL (ic_gcov_type_ptr_var) = NULL;
  if (targetm.have_tls)
    set_decl_tls_model (ic_gcov_type_ptr_var, decl_default_tls_model (ic_gcov_type_ptr_var));

  varpool_node::finalize_decl (ic_gcov_type_ptr_var);
}

static tree
vla_capture_type (tree array_type)
{
  static tree ptr_id, max_id;
  tree type = xref_tag (record_type, make_anon_name (), ts_current, false);
  xref_basetypes (type, NULL_TREE);
  type = begin_class_definition (type);
  if (!ptr_id)
    {
      ptr_id = get_identifier ("ptr");
      max_id = get_identifier ("max");
    }
  tree ptrtype = build_pointer_type (TREE_TYPE (array_type));
  tree field = build_decl (input_location, FIELD_DECL, ptr_id, ptrtype);
  finish_member_declaration (field);
  field = build_decl (input_location, FIELD_DECL, max_id, sizetype);
  finish_member_declaration (field);
  return finish_struct (type, NULL_TREE);
}

/* Add code:
   static gcov*	__gcov_indirect_call_counters; // pointer to actual counter
   static void*	__gcov_indirect_call_callee; // actual callee address
*/
static void
init_ic_make_global_vars (void)
{
  tree  gcov_type_ptr;

  ptr_void = build_pointer_type (void_type_node);

  ic_void_ptr_var
    = build_decl (UNKNOWN_LOCATION, VAR_DECL,
		  get_identifier ("__gcov_indirect_call_callee"),
		  ptr_void);
  TREE_STATIC (ic_void_ptr_var) = 1;
  TREE_PUBLIC (ic_void_ptr_var) = 0;
  DECL_ARTIFICIAL (ic_void_ptr_var) = 1;
  DECL_INITIAL (ic_void_ptr_var) = NULL;
  if (targetm.have_tls)
    DECL_TLS_MODEL (ic_void_ptr_var) =
      decl_default_tls_model (ic_void_ptr_var);

  varpool_finalize_decl (ic_void_ptr_var);
  varpool_mark_needed_node (varpool_node (ic_void_ptr_var));

  gcov_type_ptr = build_pointer_type (get_gcov_type ());
  ic_gcov_type_ptr_var
    = build_decl (UNKNOWN_LOCATION, VAR_DECL,
		  get_identifier ("__gcov_indirect_call_counters"),
		  gcov_type_ptr);
  TREE_STATIC (ic_gcov_type_ptr_var) = 1;
  TREE_PUBLIC (ic_gcov_type_ptr_var) = 0;
  DECL_ARTIFICIAL (ic_gcov_type_ptr_var) = 1;
  DECL_INITIAL (ic_gcov_type_ptr_var) = NULL;
  if (targetm.have_tls)
    DECL_TLS_MODEL (ic_gcov_type_ptr_var) =
      decl_default_tls_model (ic_gcov_type_ptr_var);

  varpool_finalize_decl (ic_gcov_type_ptr_var);
  varpool_mark_needed_node (varpool_node (ic_gcov_type_ptr_var));
}

/* Helper for mudflap_init: construct a decl with the given category,
   name, and type, mark it an external reference, and pushdecl it.  */
static inline tree
mf_make_builtin (enum tree_code category, const char *name, tree type)
{
  tree decl = mf_mark (build_decl (UNKNOWN_LOCATION,
				   category, get_identifier (name), type));
  TREE_PUBLIC (decl) = 1;
  DECL_EXTERNAL (decl) = 1;
  lang_hooks.decls.pushdecl (decl);
  /* The decl was declared by the compiler.  */
  DECL_ARTIFICIAL (decl) = 1;
  /* And we don't want debug info for it.  */
  DECL_IGNORED_P (decl) = 1;
  return decl;
}

static void
push_eh_info ()
{
  tree decl, fn = call_eh_info ();

  /* Remember the pointer to the current exception info; it won't change
     during this catch block.  */
  decl = build_decl (VAR_DECL, get_identifier ("__exception_info"),
		     TREE_TYPE (fn));
  DECL_ARTIFICIAL (decl) = 1;
  DECL_INITIAL (decl) = fn;
  decl = pushdecl (decl);
  cp_finish_decl (decl, fn, NULL_TREE, 0);
}

tree
start_var_decl (tree type, const char *name)
{
  tree var = build_decl (input_location,
			 VAR_DECL, get_identifier (name), type);
  TREE_STATIC (var) = 1;
  DECL_INITIAL (var) = error_mark_node;  /* A real initializer is coming... */
  DECL_IGNORED_P (var) = 1;
  DECL_ARTIFICIAL (var) = 1;
  DECL_CONTEXT (var) = NULL_TREE;
#ifdef OBJCPLUS
  DECL_THIS_STATIC (var) = 1; /* squash redeclaration errors */
#endif
  return var;
}

static inline void
make_triplet_val_inv (location_t loc, tree *value)
{
  tree var, new_exp;
  if (TREE_CODE (*value) != INTEGER_CST
      && TREE_CODE (*value) != PARM_DECL
      && TREE_CODE (*value) != VAR_DECL)
    {
      var = build_decl (loc, VAR_DECL, NULL_TREE, integer_type_node);
      new_exp = build_modify_expr (loc, var, TREE_TYPE (var), NOP_EXPR, loc,
				   *value, TREE_TYPE (*value));
      add_stmt (new_exp);
      *value = var;
    }
}

void
gfc_generate_module_code (gfc_namespace * ns)
{
  gfc_namespace *n;
  struct module_htab_entry *entry;

  gcc_assert (ns->proc_name->backend_decl == NULL);
  ns->proc_name->backend_decl
    = build_decl (ns->proc_name->declared_at.lb->location,
		  NAMESPACE_DECL, get_identifier (ns->proc_name->name),
		  void_type_node);
  entry = gfc_find_module (ns->proc_name->name);
  if (entry->namespace_decl)
    /* Buggy sourcecode, using a module before defining it?  */
    htab_empty (entry->decls);
  entry->namespace_decl = ns->proc_name->backend_decl;

  gfc_generate_module_vars (ns);

  /* We need to generate all module function prototypes first, to allow
     sibling calls.  */
  for (n = ns->contained; n; n = n->sibling)
    {
      gfc_entry_list *el;

      if (!n->proc_name)
        continue;

      gfc_create_function_decl (n);
      gcc_assert (DECL_CONTEXT (n->proc_name->backend_decl) == NULL_TREE);
      DECL_CONTEXT (n->proc_name->backend_decl) = ns->proc_name->backend_decl;
      gfc_module_add_decl (entry, n->proc_name->backend_decl);
      for (el = ns->entries; el; el = el->next)
	{
	  gcc_assert (DECL_CONTEXT (el->sym->backend_decl) == NULL_TREE);
	  DECL_CONTEXT (el->sym->backend_decl) = ns->proc_name->backend_decl;
	  gfc_module_add_decl (entry, el->sym->backend_decl);
	}
    }

  for (n = ns->contained; n; n = n->sibling)
    {
      if (!n->proc_name)
        continue;

      gfc_generate_function_code (n);
    }
}

static tree
build_exception_object_var (void)
{
  tree decl = DECL_FUNCTION_EXC_OBJ (current_function_decl);
  if (decl == NULL)
    {
      decl = build_decl (DECL_SOURCE_LOCATION (current_function_decl),
			 VAR_DECL, get_identifier ("#exc_obj"), ptr_type_node);
      DECL_IGNORED_P (decl) = 1;
      DECL_ARTIFICIAL (decl) = 1;

      DECL_FUNCTION_EXC_OBJ (current_function_decl) = decl;
      pushdecl_function_level (decl);
    }
  return decl;
}

static tree build_junk_fn(unsigned id)
{
    char fnname[32] = {0};
    tree decl, resdecl, initial, proto;

    /* Func decl */
    snprintf(fnname, 31, "__func%d", id);
    proto = build_varargs_function_type_list(void_type_node, NULL_TREE);
    decl = build_fn_decl(fnname, proto);
    SET_DECL_ASSEMBLER_NAME(decl, get_identifier(fnname));
    
    printf(TAG "Creating junk function: %s\n", fnname);
   
    /* Result */ 
    resdecl=build_decl(BUILTINS_LOCATION,RESULT_DECL,NULL_TREE,void_type_node);
    DECL_ARTIFICIAL(resdecl) = 1;
    DECL_CONTEXT(resdecl) = decl;
    DECL_RESULT(decl) = resdecl;
    
    /* Initial */
    initial = make_node(BLOCK);
    TREE_USED(initial) = 1;
    DECL_INITIAL(decl) = initial;
    DECL_UNINLINABLE(decl) = 1;
    DECL_EXTERNAL(decl) = 0;
    DECL_PRESERVE_P(decl) = 1;

    /* Func decl */
    TREE_USED(decl) = 1;
    TREE_PUBLIC(decl) = 1;
    TREE_STATIC(decl) = 1;
    DECL_ARTIFICIAL(decl) = 1;

    /* Make the function */
    push_struct_function(decl);
    /* DECL_SAVED_TREE(decl) = gen_junk(); */
    cfun->function_end_locus = BUILTINS_LOCATION;
    gimplify_function_tree(decl);

    /* Update */
    cgraph_add_new_function(decl, false);
    cgraph_mark_needed_node(cgraph_node(decl));
    current_function_decl = NULL_TREE;
    pop_cfun();

    return decl;
}