On Fri, Feb 16, 2024 at 04:52:20PM +0100, Jakub Jelinek wrote:
> On Fri, Feb 16, 2024 at 10:48:28AM -0500, Jason Merrill wrote:
> > On 2/16/24 04:14, Jakub Jelinek wrote:
> > > DWARF5 added DW_AT_export_symbols both for use on inline namespaces (where
> > > we emit it), but also on anonymous unions/structs (and we didn't emit that
> > > attribute there).
> > > The following patch fixes it.
> >
> > Should this involve cp_decl_dwarf_attribute like the namespace handling?
>
> I wrote it in dwarf2out.cc because the same thing needs to be done for C and
> C++ (admittedly dunno if other languages have something similar).
>
> Sure, it could be done in cp_decl_dwarf_attribute too but then it has to be
> done in c_decl_dwarf_attribute which doesn't exist. Though, it is slightly
> complicated by DW_AT_export_symbols not actually going on the DW_TAG_member
> die but on the DW_TAG_{structure,class,union}_type which DW_TAG_member uses
> as its DW_AT_type. But in order to ask the langhook, we likely need to pass
> the FIELD_DECL and not the type...
Anyway, here is a version of the patch that uses the langhook for it.
So that the langhook isn't totally abused and for performance reasons too
I've kept the DECL_NAME == NULL check on the dwarf2out.cc side and am
calling it on the type rather than decl, because type is where the attribute
should go.
2024-02-16 Jakub Jelinek <ja...@redhat.com>
PR debug/113918
gcc/
* dwarf2out.cc (gen_field_die): Emit DW_AT_export_symbols
on anonymous unions or structs for -gdwarf-5 or -gno-strict-dwarf.
gcc/c/
* c-tree.h (c_type_dwarf_attribute): Declare.
* c-objc-common.h (LANG_HOOKS_TYPE_DWARF_ATTRIBUTE): Redefine.
* c-objc-common.cc: Include dwarf2.h.
(c_type_dwarf_attribute): New function.
gcc/cp/
* cp-objcp-common.cc (cp_type_dwarf_attribute): Return 1
for DW_AT_export_symbols on anonymous structs or unions.
gcc/testsuite/
* c-c++-common/dwarf2/pr113918.c: New test.
--- gcc/dwarf2out.cc.jj 2024-02-15 13:54:29.284358101 +0100
+++ gcc/dwarf2out.cc 2024-02-16 20:38:19.718841259 +0100
@@ -25153,6 +25153,17 @@ gen_field_die (tree decl, struct vlr_con
add_accessibility_attribute (decl_die, decl);
+ /* Add DW_AT_export_symbols to anonymous unions or structs. */
+ if ((dwarf_version >= 5 || !dwarf_strict) && DECL_NAME (decl) == NULL_TREE)
+ if (tree type = member_declared_type (decl))
+ if (lang_hooks.types.type_dwarf_attribute (TYPE_MAIN_VARIANT (type),
+ DW_AT_export_symbols) != -1)
+ {
+ dw_die_ref type_die = lookup_type_die (TYPE_MAIN_VARIANT (type));
+ if (type_die && get_AT (type_die, DW_AT_export_symbols) == NULL)
+ add_AT_flag (type_die, DW_AT_export_symbols, 1);
+ }
+
/* Equate decl number to die, so that we can look up this decl later on. */
equate_decl_number_to_die (decl, decl_die);
}
--- gcc/c/c-tree.h.jj 2024-01-31 10:46:35.164761720 +0100
+++ gcc/c/c-tree.h 2024-02-16 20:43:45.993372908 +0100
@@ -731,6 +731,7 @@ extern bool c_warn_unused_global_decl (c
extern void c_initialize_diagnostics (diagnostic_context *);
extern bool c_var_mod_p (tree x, tree fn);
extern alias_set_type c_get_alias_set (tree);
+extern int c_type_dwarf_attribute (const_tree, int);
/* in c-typeck.cc */
extern int in_alignof;
--- gcc/c/c-objc-common.h.jj 2024-01-03 12:06:52.973862999 +0100
+++ gcc/c/c-objc-common.h 2024-02-16 20:42:21.073535465 +0100
@@ -119,6 +119,9 @@ static const scoped_attribute_specs *con
#undef LANG_HOOKS_GIMPLIFY_EXPR
#define LANG_HOOKS_GIMPLIFY_EXPR c_gimplify_expr
+#undef LANG_HOOKS_TYPE_DWARF_ATTRIBUTE
+#define LANG_HOOKS_TYPE_DWARF_ATTRIBUTE c_type_dwarf_attribute
+
#undef LANG_HOOKS_OMP_PREDETERMINED_SHARING
#define LANG_HOOKS_OMP_PREDETERMINED_SHARING c_omp_predetermined_sharing
--- gcc/c/c-objc-common.cc.jj 2024-01-03 12:06:53.213859637 +0100
+++ gcc/c/c-objc-common.cc 2024-02-16 20:45:24.649022305 +0100
@@ -30,6 +30,7 @@ along with GCC; see the file COPYING3.
#include "gcc-rich-location.h"
#include "stringpool.h"
#include "attribs.h"
+#include "dwarf2.h"
static bool c_tree_printer (pretty_printer *, text_info *, const char *,
int, bool, bool, bool, bool *, const char **);
@@ -446,3 +447,25 @@ instantiation_dependent_expression_p (tr
{
return false;
}
+
+/* Return -1 if dwarf ATTR shouldn't be added for TYPE, or the attribute
+ value otherwise. */
+int
+c_type_dwarf_attribute (const_tree type, int attr)
+{
+ if (type == NULL_TREE)
+ return -1;
+
+ switch (attr)
+ {
+ case DW_AT_export_symbols:
+ if (RECORD_OR_UNION_TYPE_P (type) && TYPE_NAME (type) == NULL_TREE)
+ return 1;
+ break;
+
+ default:
+ break;
+ }
+
+ return -1;
+}
--- gcc/cp/cp-objcp-common.cc.jj 2024-02-13 12:50:21.666846296 +0100
+++ gcc/cp/cp-objcp-common.cc 2024-02-16 20:40:51.374763528 +0100
@@ -410,6 +410,15 @@ cp_type_dwarf_attribute (const_tree type
return 1;
break;
+ case DW_AT_export_symbols:
+ if (RECORD_OR_UNION_TYPE_P (type))
+ {
+ tree type_id = TYPE_IDENTIFIER (type);
+ if (type_id == NULL_TREE || IDENTIFIER_ANON_P (type_id))
+ return 1;
+ }
+ break;
+
default:
break;
}
--- gcc/testsuite/c-c++-common/dwarf2/pr113918.c.jj 2024-02-16
20:27:13.996961811 +0100
+++ gcc/testsuite/c-c++-common/dwarf2/pr113918.c 2024-02-16
20:27:13.996961811 +0100
@@ -0,0 +1,33 @@
+/* PR debug/113918 */
+/* { dg-do compile } */
+/* { dg-options "-gdwarf-5 -dA -fno-merge-debug-strings" } */
+
+struct S {
+ union {
+ int i;
+ long long j;
+ };
+ struct {
+ int k;
+ long long l;
+ };
+ union {
+ int m;
+ long long n;
+ } u;
+ struct {
+ int o;
+ long long p;
+ } v;
+} s;
+
+int
+main ()
+{
+ s.i = 1;
+ s.k = 2;
+ s.u.m = 3;
+ s.v.o = 4;
+}
+
+/* { dg-final { scan-assembler-times "DW_AT_export_symbols" 4 } } */
Jakub
