bool
symtab_semantically_equivalent_p (symtab_node *a,
symtab_node *b)
{
enum availability avail;
symtab_node *ba;
symtab_node *bb;
/* Equivalent functions are equivalent. */
if (a->decl == b->decl)
return true;
/* If symbol is not overwritable by different implementation,
walk to the base object it defines. */
ba = symtab_alias_ultimate_target (a, &avail);
if (avail >= AVAIL_AVAILABLE)
{
if (ba == b)
return true;
}
else
ba = a;
bb = symtab_alias_ultimate_target (b, &avail);
if (avail >= AVAIL_AVAILABLE)
{
if (a == bb)
return true;
}
else
bb = b;
return bb == ba;
}
symtab_node *
symtab_nonoverwritable_alias (symtab_node *node)
{
tree new_decl;
symtab_node *new_node = NULL;
/* First try to look up existing alias or base object
(if that is already non-overwritable). */
node = symtab_alias_ultimate_target (node, NULL);
gcc_assert (!node->alias && !node->weakref);
symtab_for_node_and_aliases (node, symtab_nonoverwritable_alias_1,
(void *)&new_node, true);
if (new_node)
return new_node;
#ifndef ASM_OUTPUT_DEF
/* If aliases aren't supported by the assembler, fail. */
return NULL;
#endif
/* Otherwise create a new one. */
new_decl = copy_node (node->decl);
DECL_DLLIMPORT_P (new_decl) = 0;
DECL_NAME (new_decl) = clone_function_name (node->decl, "localalias");
if (TREE_CODE (new_decl) == FUNCTION_DECL)
DECL_STRUCT_FUNCTION (new_decl) = NULL;
DECL_INITIAL (new_decl) = NULL;
SET_DECL_ASSEMBLER_NAME (new_decl, DECL_NAME (new_decl));
SET_DECL_RTL (new_decl, NULL);
/* Update the properties. */
DECL_EXTERNAL (new_decl) = 0;
if (DECL_ONE_ONLY (node->decl))
DECL_SECTION_NAME (new_decl) = NULL;
DECL_COMDAT_GROUP (new_decl) = 0;
TREE_PUBLIC (new_decl) = 0;
DECL_COMDAT (new_decl) = 0;
DECL_WEAK (new_decl) = 0;
DECL_VIRTUAL_P (new_decl) = 0;
if (TREE_CODE (new_decl) == FUNCTION_DECL)
{
DECL_STATIC_CONSTRUCTOR (new_decl) = 0;
DECL_STATIC_DESTRUCTOR (new_decl) = 0;
new_node = cgraph_create_function_alias
(new_decl, node->decl);
}
else
new_node = varpool_create_variable_alias (new_decl,
node->decl);
symtab_resolve_alias (new_node, node);
gcc_assert (decl_binds_to_current_def_p (new_decl));
return new_node;
}
void
enqueue_references (symtab_node **first,
symtab_node *symbol)
{
int i;
struct ipa_ref *ref;
for (i = 0; ipa_ref_list_reference_iterate (&symbol->ref_list, i, ref); i++)
{
symtab_node *node = symtab_alias_ultimate_target (ref->referred, NULL);
if (!node->aux && node->definition)
{
node->aux = *first;
*first = node;
}
}
if (cgraph_node *cnode = dyn_cast <cgraph_node *> (symbol))
{
struct cgraph_edge *edge;
for (edge = cnode->callees; edge; edge = edge->next_callee)
if (!edge->inline_failed)
enqueue_references (first, edge->callee);
else
{
symtab_node *node = symtab_alias_ultimate_target (edge->callee,
NULL);
if (!node->aux && node->definition)
{
node->aux = *first;
*first = node;
}
}
}
}
bool
symtab_resolve_alias (symtab_node node, symtab_node target)
{
symtab_node n;
gcc_assert (!node->symbol.analyzed
&& !vec_safe_length (node->symbol.ref_list.references));
/* Never let cycles to creep into the symbol table alias references;
those will make alias walkers to be infinite. */
for (n = target; n && n->symbol.alias;
n = n->symbol.analyzed ? symtab_alias_target (n) : NULL)
if (n == node)
{
if (is_a <cgraph_node> (node))
error ("function %q+D part of alias cycle", node->symbol.decl);
else if (is_a <varpool_node> (node))
error ("variable %q+D part of alias cycle", node->symbol.decl);
else
gcc_unreachable ();
node->symbol.alias = false;
return false;
}
/* "analyze" the node - i.e. mark the reference. */
node->symbol.definition = true;
node->symbol.alias = true;
node->symbol.analyzed = true;
ipa_record_reference (node, target, IPA_REF_ALIAS, NULL);
/* Alias targets become reudndant after alias is resolved into an reference.
We do not want to keep it around or we would have to mind updating them
when renaming symbols. */
node->symbol.alias_target = NULL;
if (node->symbol.cpp_implicit_alias && cgraph_state >= CGRAPH_STATE_CONSTRUCTION)
fixup_same_cpp_alias_visibility (node, target);
/* If alias has address taken, so does the target. */
if (node->symbol.address_taken)
symtab_alias_ultimate_target (target, NULL)->symbol.address_taken = true;
return true;
}
static unsigned int
ipa_comdats (void)
{
pointer_map<tree> map;
pointer_map<symtab_node *> comdat_head_map;
symtab_node *symbol;
bool comdat_group_seen = false;
symtab_node *first = (symtab_node *) (void *) 1;
tree group;
/* Start the dataflow by assigning comdat group to symbols that are in comdat
groups already. All other externally visible symbols must stay, we use
ERROR_MARK_NODE as bottom for the propagation. */
FOR_EACH_DEFINED_SYMBOL (symbol)
if (!symtab_real_symbol_p (symbol))
;
else if ((group = symbol->get_comdat_group ()) != NULL)
{
*map.insert (symbol) = group;
*comdat_head_map.insert (group) = symbol;
comdat_group_seen = true;
/* Mark the symbol so we won't waste time visiting it for dataflow. */
symbol->aux = (symtab_node *) (void *) 1;
}
/* See symbols that can not be privatized to comdats; that is externally
visible symbols or otherwise used ones. We also do not want to mangle
user section names. */
else if (symbol->externally_visible
|| symbol->force_output
|| symbol->used_from_other_partition
|| TREE_THIS_VOLATILE (symbol->decl)
|| symbol->get_section ()
|| (TREE_CODE (symbol->decl) == FUNCTION_DECL
&& (DECL_STATIC_CONSTRUCTOR (symbol->decl)
|| DECL_STATIC_DESTRUCTOR (symbol->decl))))
{
*map.insert (symtab_alias_ultimate_target (symbol, NULL)) = error_mark_node;
/* Mark the symbol so we won't waste time visiting it for dataflow. */
symbol->aux = (symtab_node *) (void *) 1;
}
else
{
/* Enqueue symbol for dataflow. */
symbol->aux = first;
first = symbol;
}
if (!comdat_group_seen)
{
FOR_EACH_DEFINED_SYMBOL (symbol)
symbol->aux = NULL;
return 0;
}
/* The actual dataflow. */
while (first != (void *) 1)
{
tree group = NULL;
tree newgroup, *val;
symbol = first;
first = (symtab_node *)first->aux;
/* Get current lattice value of SYMBOL. */
val = map.contains (symbol);
if (val)
group = *val;
/* If it is bottom, there is nothing to do; do not clear AUX
so we won't re-queue the symbol. */
if (group == error_mark_node)
continue;
newgroup = propagate_comdat_group (symbol, group, map);
/* If nothing changed, proceed to next symbol. */
if (newgroup == group)
{
symbol->aux = NULL;
continue;
}
/* Update lattice value and enqueue all references for re-visiting. */
gcc_assert (newgroup);
if (val)
*val = newgroup;
else
*map.insert (symbol) = newgroup;
enqueue_references (&first, symbol);
/* We may need to revisit the symbol unless it is BOTTOM. */
if (newgroup != error_mark_node)
symbol->aux = NULL;
}
/* Finally assign symbols to the sections. */
FOR_EACH_DEFINED_SYMBOL (symbol)
{
symbol->aux = NULL;
if (!symbol->get_comdat_group ()
&& !symbol->alias
&& symtab_real_symbol_p (symbol))
{
tree group = *map.contains (symbol);
if (group == error_mark_node)
continue;
if (dump_file)
{
fprintf (dump_file, "Localizing symbol\n");
dump_symtab_node (dump_file, symbol);
fprintf (dump_file, "To group: %s\n", IDENTIFIER_POINTER (group));
}
symtab_for_node_and_aliases (symbol, set_comdat_group,
*comdat_head_map.contains (group), true);
}
}
return 0;
}
