[gcc r14-9385] dwarf2out: Emit DW_AT_export_symbols on anon unions/structs [PR113918]

[gcc r14-9385] dwarf2out: Emit DW_AT_export_symbols on anon unions/structs [PR113918]

[Jakub Jelinek]

https://gcc.gnu.org/g:05109b1bd5ef4ee9d78fe17d4563889694a26d05

commit r14-9385-g05109b1bd5ef4ee9d78fe17d4563889694a26d05
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Fri Mar 8 09:14:32 2024 +0100

    dwarf2out: Emit DW_AT_export_symbols on anon unions/structs [PR113918]
    
    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.
    
    2024-03-08  Jakub Jelinek  <jakub@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.

Diff:
---
 gcc/c/c-objc-common.cc                       | 23 +++++++++++++++++++
 gcc/c/c-objc-common.h                        |  3 +++
 gcc/c/c-tree.h                               |  1 +
 gcc/cp/cp-objcp-common.cc                    |  5 +++++
 gcc/dwarf2out.cc                             | 11 ++++++++++
 gcc/testsuite/c-c++-common/dwarf2/pr113918.c | 33 ++++++++++++++++++++++++++++
 6 files changed, 76 insertions(+)

diff --git a/gcc/c/c-objc-common.cc b/gcc/c/c-objc-common.cc
index 116b73af6db..b7c72d2609c 100644
--- a/gcc/c/c-objc-common.cc
+++ b/gcc/c/c-objc-common.cc
@@ -30,6 +30,7 @@ along with GCC; see the file COPYING3.  If not see
 #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 (tree)
 {
   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;
+}
diff --git a/gcc/c/c-objc-common.h b/gcc/c/c-objc-common.h
index 35a59988e90..20af5a5bb94 100644
--- a/gcc/c/c-objc-common.h
+++ b/gcc/c/c-objc-common.h
@@ -119,6 +119,9 @@ static const scoped_attribute_specs *const c_objc_attribute_table[] =
 #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
 
diff --git a/gcc/c/c-tree.h b/gcc/c/c-tree.h
index 1fba9c8dae7..22b0009874b 100644
--- a/gcc/c/c-tree.h
+++ b/gcc/c/c-tree.h
@@ -731,6 +731,7 @@ extern bool c_warn_unused_global_decl (const_tree);
 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;
diff --git a/gcc/cp/cp-objcp-common.cc b/gcc/cp/cp-objcp-common.cc
index 85dde0459fa..86e0b49d46b 100644
--- a/gcc/cp/cp-objcp-common.cc
+++ b/gcc/cp/cp-objcp-common.cc
@@ -410,6 +410,11 @@ cp_type_dwarf_attribute (const_tree type, int attr)
 	return 1;
       break;
 
+    case DW_AT_export_symbols:
+      if (ANON_AGGR_TYPE_P (type))
+	return 1;
+      break;
+
     default:
       break;
     }
diff --git a/gcc/dwarf2out.cc b/gcc/dwarf2out.cc
index 03d73f9eecd..87e4240b871 100644
--- a/gcc/dwarf2out.cc
+++ b/gcc/dwarf2out.cc
@@ -25162,6 +25162,17 @@ gen_field_die (tree decl, struct vlr_context *ctx, dw_die_ref context_die)
 
   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);
 }
diff --git a/gcc/testsuite/c-c++-common/dwarf2/pr113918.c b/gcc/testsuite/c-c++-common/dwarf2/pr113918.c
new file mode 100644
index 00000000000..f72a6c4338f
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/dwarf2/pr113918.c
@@ -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 } } */