In GCC 4.4.3, I found a case where a defining declaration of a subprogram
was included within the DIE structure for the containing class declaration,
and the class was moved into a DWARF-4 type unit, causing a later ICE in
output_pubnames. That case doesn't cause a problem in 4.5 and later, as
the subprogram DIE is generated at the top level with a DW_AT_specification
pointing to the declaration DIE inside the class. Nevertheless, I think
it's a good safety measure to ensure that if a class does contain a
subprogram definition, it shouldn't be moved to a type unit -- such a
type would never be identical across different compilation units.
This patch checks for classes that contain defining declarations of
subprograms, and does not move such classes into a comdat type unit.
OK for trunk? I don't think it's critical to 4.6, but if it's acceptable
for 4.6, that would be nice, too.
-cary
Tested:
Bootstrapped on x86_64.
ChangeLog:
2011-04-25 Cary Coutant <ccout...@google.com>
* gcc/dwarf2out.c (contains_subprogram_definition): New function.
(should_move_die_to_comdat): Call it.
diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index f3c4c09..8262cc7 100644
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -10018,6 +10018,20 @@ is_nested_in_subprogram (dw_die_ref die)
return local_scope_p (decl);
}
+/* Return non-zero if this DIE contains a defining declaration of a
+ subprogram. */
+
+static int
+contains_subprogram_definition (dw_die_ref die)
+{
+ dw_die_ref c;
+
+ if (die->die_tag == DW_TAG_subprogram && ! is_declaration_die (die))
+ return 1;
+ FOR_EACH_CHILD (die, c, if (contains_subprogram_definition(c)) return 1);
+ return 0;
+}
+
/* Return non-zero if this is a type DIE that should be moved to a
COMDAT .debug_types section. */
@@ -10034,7 +10048,8 @@ should_move_die_to_comdat (dw_die_ref die)
subprogram. */
if (is_declaration_die (die)
|| get_AT (die, DW_AT_abstract_origin)
- || is_nested_in_subprogram (die))
+ || is_nested_in_subprogram (die)
+ || contains_subprogram_definition (die))
return 0;
return 1;
case DW_TAG_array_type:
--
This patch is available for review at http://codereview.appspot.com/4433068
