I have committed the following patch to make debug refs prevail
in LTO tree merging. This will fix mixing -g0 and -g units as
well as cases where we fail to emit early debug for some decls
in one unit but emit them for the copy in a second like for
the testcase. So for the testcase a FE fix would be possible
as well to not lose debug info.
Bootstrapped and tested on x86_64-unknown-linux-gnu.
Richard.
2018-07-20 Richard Biener <rguent...@suse.de>
PR debug/86585
* dwarf2out.c (dwarf2out_die_ref_for_decl): Test in_lto_p
to cover -flto-partition=none.
lto/
* lto.c (unify_scc): Before we throw away an SCC see if we
can amend prevailing single-entry SCC with debug refs.
* g++.dg/lto/pr86585_0.C: New testcase.
* g++.dg/lto/pr86585_1.C: Likewise.
diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index bd45e0b0685..8377cbc5dd1 100644
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -5851,8 +5851,7 @@ dwarf2out_die_ref_for_decl (tree decl, const char **sym,
{
dw_die_ref die;
- if ((flag_wpa || flag_incremental_link == INCREMENTAL_LINK_LTO)
- && !decl_die_table)
+ if (in_lto_p && !decl_die_table)
return false;
if (TREE_CODE (decl) == BLOCK)
@@ -5865,8 +5864,7 @@ dwarf2out_die_ref_for_decl (tree decl, const char **sym,
/* During WPA stage and incremental linking we currently use DIEs
to store the decl <-> label + offset map. That's quite inefficient
but it works for now. */
- if (flag_wpa
- || flag_incremental_link == INCREMENTAL_LINK_LTO)
+ if (in_lto_p)
{
dw_die_ref ref = get_AT_ref (die, DW_AT_abstract_origin);
if (!ref)
diff --git a/gcc/lto/lto.c b/gcc/lto/lto.c
index d1add15efeb..8db280ecefc 100644
--- a/gcc/lto/lto.c
+++ b/gcc/lto/lto.c
@@ -1638,6 +1638,21 @@ unify_scc (struct data_in *data_in, unsigned from,
to the tree node mapping computed by compare_tree_sccs. */
if (len == 1)
{
+ /* If we got a debug reference queued, see if the prevailing
+ tree has a debug reference and if not, register the one
+ for the tree we are about to throw away. */
+ if (dref_queue.length () == 1)
+ {
+ dref_entry e = dref_queue.pop ();
+ gcc_assert (e.decl
+ == streamer_tree_cache_get_tree (cache, from));
+ const char *sym;
+ unsigned HOST_WIDE_INT off;
+ if (!debug_hooks->die_ref_for_decl (pscc->entries[0], &sym,
+ &off))
+ debug_hooks->register_external_die (pscc->entries[0],
+ e.sym, e.off);
+ }
lto_maybe_register_decl (data_in, pscc->entries[0], from);
streamer_tree_cache_replace_tree (cache, pscc->entries[0], from);
}
@@ -1669,7 +1684,9 @@ unify_scc (struct data_in *data_in, unsigned from,
free_node (scc->entries[i]);
}
- /* Drop DIE references. */
+ /* Drop DIE references.
+ ??? Do as in the size-one SCC case which involves sorting
+ the queue. */
dref_queue.truncate (0);
break;
diff --git a/gcc/testsuite/g++.dg/lto/pr86585_0.C
b/gcc/testsuite/g++.dg/lto/pr86585_0.C
new file mode 100644
index 00000000000..2c3ae9da414
--- /dev/null
+++ b/gcc/testsuite/g++.dg/lto/pr86585_0.C
@@ -0,0 +1,18 @@
+// { dg-lto-do link }
+// { dg-require-effective-target fpic }
+// { dg-require-effective-target shared }
+// { dg-lto-options { { -flto -g -nostdlib -shared -fPIC } } }
+namespace Inkscape {
+ class a;
+}
+class b {
+ Inkscape::a *c;
+ virtual void d();
+};
+class e {
+ b f;
+};
+class g : e {
+ void h();
+};
+void g::h() {}
diff --git a/gcc/testsuite/g++.dg/lto/pr86585_1.C
b/gcc/testsuite/g++.dg/lto/pr86585_1.C
new file mode 100644
index 00000000000..ebcbe126768
--- /dev/null
+++ b/gcc/testsuite/g++.dg/lto/pr86585_1.C
@@ -0,0 +1,24 @@
+struct a {
+ struct b {
+ b();
+ } c;
+};
+class d {
+ a e;
+};
+namespace aa {
+ class h {};
+} // namespace aa
+class k {
+ typedef aa::h f;
+ f g;
+};
+namespace Inkscape {
+ class l {
+ k i;
+class : d {
+ } j;
+ l();
+ };
+ l::l() {}
+} // namespace Inkscape
