Patchwork PR debug/45682 - wrong struct DIE nesting with -fdebug-types-section

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Submitter Cary Coutant
Date Jan. 19, 2012, 10:47 p.m.
Message ID <CAHACq4rnv5wHmD_RG18YF6QPKQjQnNUaRtHOXXpNUVinRY3p8A@mail.gmail.com>
Download mbox | patch
Permalink /patch/136915/
State New
Headers show

Comments

Cary Coutant - Jan. 19, 2012, 10:47 p.m.
>> Would you consider it OK with a comment?
>
> Yes.
>
>> How about if I call copy_declaration_context directly from
>> remove_child_or_replace_with_skeleton, instead of calling them
>> sequentially in break_out_comdat_types?
>
> OK.

Updated patch attached. I fixed the regex so the test is independent
of whether the strings are emitted with DW_FORM_string or
DW_FORM_strp.

Bootstrapped on x86_64, no regressions.

OK for trunk, or hold for next stage 1?

-cary


2012-01-19   Cary Coutant  <ccoutant@google.com>
	     Dodji Seketeli  <dodji@redhat.com>

gcc/ChangeLog:

	PR debug/45682
	* dwarf2out.c (copy_declaration_context): Return ref to parent
	of declaration DIE, if necessary.
	(remove_child_or_replace_with_skeleton): Add new parameter; update
	caller.  Place skeleton DIE under parent DIE of original declaration.
	Move call to copy_declaration_context to here ...
	(break_out_comdat_types): ... from here.

gcc/testsuite/ChangeLog:

	PR debug/45682
	* g++.dg/debug/dwarf2/nested-3.C: New test.
2012-01-19   Cary Coutant  <ccoutant@google.com>
	     Dodji Seketeli  <dodji@redhat.com>

gcc/ChangeLog:

	PR debug/45682
	* dwarf2out.c (copy_declaration_context): Return ref to parent
	of declaration DIE, if necessary.
	(remove_child_or_replace_with_skeleton): Add new parameter; update
	caller.  Place skeleton DIE under parent DIE of original declaration.
	Move call to copy_declaration_context to here ...
	(break_out_comdat_types): ... from here.

gcc/testsuite/ChangeLog:

	PR debug/45682
	* g++.dg/debug/dwarf2/nested-3.C: New test.


commit 959d3b18ff6812a0316960ac49b283c11fd20460
Author: Cary Coutant <ccoutant@google.com>
Date:   Thu Jan 19 14:00:59 2012 -0800

    PR debug/45682: Place skeleton DIE under parent of original decl.
Jason Merrill - Jan. 20, 2012, 2:15 p.m.
On 01/19/2012 05:47 PM, Cary Coutant wrote:
> +/* Copy the declaration context to the new type unit DIE.  This includes
>      any surrounding namespace or type declarations.  If the DIE has an
>      AT_specification attribute, it also includes attributes and children
>      attached to the specification.  */
>
> -static void
> +static dw_die_ref
>   copy_declaration_context (dw_die_ref unit, dw_die_ref die)

Need to update the comment to cover the return value.  OK for 4.7 with 
that change.

Jason

Patch

diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index f9f4295..6101087 100644
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -3302,11 +3302,12 @@  static int should_move_die_to_comdat (dw_die_ref);
 static dw_die_ref clone_as_declaration (dw_die_ref);
 static dw_die_ref clone_die (dw_die_ref);
 static dw_die_ref clone_tree (dw_die_ref);
-static void copy_declaration_context (dw_die_ref, dw_die_ref);
+static dw_die_ref copy_declaration_context (dw_die_ref, dw_die_ref);
 static void generate_skeleton_ancestor_tree (skeleton_chain_node *);
 static void generate_skeleton_bottom_up (skeleton_chain_node *);
 static dw_die_ref generate_skeleton (dw_die_ref);
 static dw_die_ref remove_child_or_replace_with_skeleton (dw_die_ref,
+                                                         dw_die_ref,
                                                          dw_die_ref);
 static void break_out_comdat_types (dw_die_ref);
 static dw_die_ref copy_ancestor_tree (dw_die_ref, dw_die_ref, htab_t);
@@ -7070,16 +7071,17 @@  clone_as_declaration (dw_die_ref die)
   return clone;
 }
 
-/* Copy the declaration context to the new compile unit DIE.  This includes
+/* Copy the declaration context to the new type unit DIE.  This includes
    any surrounding namespace or type declarations.  If the DIE has an
    AT_specification attribute, it also includes attributes and children
    attached to the specification.  */
 
-static void
+static dw_die_ref
 copy_declaration_context (dw_die_ref unit, dw_die_ref die)
 {
   dw_die_ref decl;
   dw_die_ref new_decl;
+  dw_die_ref orig_parent = NULL;
 
   decl = get_AT_ref (die, DW_AT_specification);
   if (decl == NULL)
@@ -7090,6 +7092,10 @@  copy_declaration_context (dw_die_ref unit, dw_die_ref die)
       dw_die_ref c;
       dw_attr_ref a;
 
+      /* The original DIE will be changed to a declaration, and must
+         be moved to be a child of the original declaration DIE.  */
+      orig_parent = decl->die_parent;
+
       /* Copy the type node pointer from the new DIE to the original
          declaration DIE so we can forward references later.  */
       decl->die_id.die_type_node = die->die_id.die_type_node;
@@ -7118,6 +7124,8 @@  copy_declaration_context (dw_die_ref unit, dw_die_ref die)
           add_AT_specification (die, new_decl);
         }
     }
+
+  return orig_parent;
 }
 
 /* Generate the skeleton ancestor tree for the given NODE, then clone
@@ -7201,17 +7209,23 @@  generate_skeleton (dw_die_ref die)
   return node.new_die;
 }
 
-/* Remove the DIE from its parent, possibly replacing it with a cloned
-   declaration.  The original DIE will be moved to a new compile unit
-   so that existing references to it follow it to the new location.  If
-   any of the original DIE's descendants is a declaration, we need to
-   replace the original DIE with a skeleton tree and move the
-   declarations back into the skeleton tree.  */
+/* Remove the CHILD DIE from its parent, possibly replacing it with a cloned
+   declaration.  The original DIE is moved to a new compile unit so that
+   existing references to it follow it to the new location.  If any of the
+   original DIE's descendants is a declaration, we need to replace the
+   original DIE with a skeleton tree and move the declarations back into the
+   skeleton tree.  */
 
 static dw_die_ref
-remove_child_or_replace_with_skeleton (dw_die_ref child, dw_die_ref prev)
+remove_child_or_replace_with_skeleton (dw_die_ref unit, dw_die_ref child,
+				       dw_die_ref prev)
 {
-  dw_die_ref skeleton;
+  dw_die_ref skeleton, orig_parent;
+
+  /* Copy the declaration context to the type unit DIE.  If the returned
+     ORIG_PARENT is not NULL, the skeleton needs to be added as a child of
+     that DIE.  */
+  orig_parent = copy_declaration_context (unit, c);
 
   skeleton = generate_skeleton (child);
   if (skeleton == NULL)
@@ -7219,7 +7233,19 @@  remove_child_or_replace_with_skeleton (dw_die_ref child, dw_die_ref prev)
   else
     {
       skeleton->die_id.die_type_node = child->die_id.die_type_node;
-      replace_child (child, skeleton, prev);
+
+      /* If the original DIE was a specification, we need to put
+         the skeleton under the parent DIE of the declaration.
+	 This leaves the original declaration in the tree, but
+	 it will be pruned later since there are no longer any
+	 references to it.  */
+      if (new_parent != NULL)
+	{
+	  remove_child_with_prev (child, prev);
+	  add_child_die (new_parent, skeleton);
+	}
+      else
+	replace_child (child, skeleton, prev);
     }
 
   return skeleton;
@@ -7247,7 +7273,7 @@  break_out_comdat_types (dw_die_ref die)
     next = (c == first ? NULL : c->die_sib);
     if (should_move_die_to_comdat (c))
       {
-        dw_die_ref replacement;
+        dw_die_ref replacement, new_parent;
 	comdat_type_node_ref type_node;
 
         /* Create a new type unit DIE as the root for the new tree, and
@@ -7264,11 +7290,9 @@  break_out_comdat_types (dw_die_ref die)
         generate_type_signature (c, type_node);
 
         /* Copy the declaration context, attributes, and children of the
-           declaration into the new compile unit DIE.  */
-	copy_declaration_context (unit, c);
-
-        /* Remove this DIE from the main CU.  */
-	replacement = remove_child_or_replace_with_skeleton (c, prev);
+           declaration into the new type unit DIE, then remove this DIE
+	   from the main CU (or replace it with a skeleton if necessary).  */
+	replacement = remove_child_or_replace_with_skeleton (unit, c, prev);
 
         /* Break out nested types into their own type units.  */
         break_out_comdat_types (c);
diff --git a/gcc/testsuite/g++.dg/debug/dwarf2/nested-3.C b/gcc/testsuite/g++.dg/debug/dwarf2/nested-3.C
new file mode 100644
index 0000000..707f02d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/debug/dwarf2/nested-3.C
@@ -0,0 +1,54 @@ 
+// Origin: PR debug/45682
+// { dg-options "-g -fno-merge-debug-strings -gdwarf-4 -dA -fdebug-types-section" }
+
+namespace thread {
+
+class Executor {
+ public:
+  static Executor* CurrentExecutor();
+};
+
+}
+
+namespace thread {
+
+Executor* Executor::CurrentExecutor() {
+  return 0;
+}
+
+}
+
+thread::Executor *te;
+
+int
+main ()
+{
+    return 0;
+}
+
+// We want to express the fact that the DIE for the definition of
+// 'Executor::CurrentExecutor' is a grand-child of the DIE for the
+// namespace 'thread'.  We must have something like this output:
+//	.uleb128 0x8	# (DIE (0x29) DW_TAG_namespace)
+//	.ascii "thread\0"	# DW_AT_name
+//	.byte   0x1	# DW_AT_decl_file (.../testsuite/g++.dg/debug/dwarf2/nested-3.C)
+//	.byte   0x4	# DW_AT_decl_line
+//	.long   0x4b	# DW_AT_sibling
+//	.uleb128 0x9	# (DIE (0x34) DW_TAG_class_type)
+//	.long   .LASF0	# DW_AT_name: "Executor"
+//			# DW_AT_declaration
+//	.uleb128 0x5	# (DIE (0x39) DW_TAG_subprogram)
+//			# DW_AT_external
+//	.long   .LASF1	# DW_AT_name: "CurrentExecutor"
+//	.byte   0x1	# DW_AT_decl_file (.../testsuite/g++.dg/debug/dwarf2/nested-3.C)
+//	.byte   0x8	# DW_AT_decl_line
+//	.long   .LASF2	# DW_AT_linkage_name: "_ZN6thread8Executor15CurrentExecutorEv"
+//	.long   0x4b	# DW_AT_type
+//	.byte   0x1	# DW_AT_accessibility
+//			# DW_AT_declaration
+//	.byte   0	# end of children of DIE 0x34
+//	.byte   0	# end of children of DIE 0x29
+//
+//     Hence the scary regexp:
+//
+//     { dg-final { scan-assembler "\[^\n\r\]*\\(DIE \\(0x(\[0-9a-f\]+)\\) DW_TAG_namespace\\)\[\n\r\]+\[^\n\r\]*\"thread\[\^\n\r]+\[\n\r\]+(\[^\n\r\]*\[\n\r\]+)+\[^\n\r\]*\\(DIE \\(0x(\[0-9a-f\]+)\\) DW_TAG_class_type\\)\[\n\r\]+\[^\n\r\]*\"Executor\[^\n\r\]+\[\n\r\]+\[^\n\r\]*DW_AT_declaration\[\n\r\]+\[^\n\r\]*\\(DIE\[^\n\r\]*DW_TAG_subprogram\\)\[\n\r\]+(\[^\n\r\]*\[\n\r\]+)+\[^\n\r\]*\"CurrentExecutor\[^\n\r\]+\[\n\r\]+(\[^\n\r\]*\[\n\r\]+)+(\[^\n\r\]*\[\n\r\]+)+\[^\n\r\]*end of children of DIE 0x\\3\[\n\r]+\[^\n\r\]*end of children of DIE 0x\\1\[\n\r]+" } }