Re: [debug/88006] -fdebug-types-section gives undefined ref

[Nathan Sidwell]

On 11/14/18 7:33 AM, Richard Biener wrote:

Hmm, there is reference_to_unused () used in a related case.  But generally
for late emission such references are "OK" and expected to be pruned
later by resolve_addr () (which I see we do not call for type units?!).  Quote:
/* Resolve DW_OP_addr and DW_AT_const_value CONST_STRING arguments to
    an address in .rodata section if the string literal is emitted there,
    or remove the containing location list or replace DW_AT_const_value
    with DW_AT_location and empty location expression, if it isn't found
    in .rodata.  Similarly for SYMBOL_REFs, keep only those that refer
    to something that has been emitted in the current CU.  */

static void
resolve_addr (dw_die_ref die)
{

That does seem to work.  The attached survise bootstrapping on 
x86_64-linux, ok?

nathan

--
Nathan Sidwell
2018-11-14  Nathan Sidwell  <nat...@acm.org>

	PR debug/88006
	PR debug/87462
	* dwarf2out.c (dwarf2out_finish): Apply resolve_addr to comdat
	type list.

	* g++.dg/debug/dwarf2/pr87462.C: New.
	* g++.dg/debug/dwarf2/pr88006.C: New.

Index: dwarf2out.c
===================================================================
--- dwarf2out.c	(revision 266082)
+++ dwarf2out.c	(working copy)
@@ -31182,6 +31182,8 @@ dwarf2out_finish (const char *filename)
     FOR_EACH_CHILD (die, c, gcc_assert (! c->die_mark));
   }
 #endif
+  for (ctnode = comdat_type_list; ctnode != NULL; ctnode = ctnode->next)
+    resolve_addr (ctnode->root_die);
   resolve_addr (comp_unit_die ());
   move_marked_base_types ();
 
Index: testsuite/g++.dg/debug/dwarf2/pr87462.C
===================================================================
--- testsuite/g++.dg/debug/dwarf2/pr87462.C	(revision 0)
+++ testsuite/g++.dg/debug/dwarf2/pr87462.C	(working copy)
@@ -0,0 +1,20 @@
+// { dg-additional-options "-dA -std=gnu++17 -gdwarf-4 -O1 -fdebug-types-section" }
+// reject .pseudo label, but "label" is ok.
+// { dg-final { scan-assembler-not "\[^L\"\]_ZN5Test18testFuncEv" } }
+// undefined ref to _ZN5Test18testFuncEv
+
+class Test1 {
+public:
+  static int testFunc() { return 1; }
+};
+
+template <typename T,
+          T (*funcImpl)()>
+class TestWrapper {
+public:
+  static T func() __attribute((noinline)) { return (*funcImpl)(); } 
+};
+
+int main() {
+  return TestWrapper<int, &Test1::testFunc>::func();
+}
Index: testsuite/g++.dg/debug/dwarf2/pr88006.C
===================================================================
--- testsuite/g++.dg/debug/dwarf2/pr88006.C	(revision 0)
+++ testsuite/g++.dg/debug/dwarf2/pr88006.C	(working copy)
@@ -0,0 +1,39 @@
+// { dg-additional-options "-dA -std=gnu++17 -gdwarf-4 -O1 -fdebug-types-section" }
+// reject .pseudo label, but "label" is ok.
+// { dg-final { scan-assembler-not "\[^\"\]_ZN3Foo4mfunEv" } }
+// undefined ref to _ZN3Foo4mfunEv
+
+struct Foo {
+  void mfun () {}
+};
+
+struct A { static constexpr bool Value = false; };
+
+template <bool> struct B { typedef int Type; };
+
+class Arg
+{
+  template <typename Unused> struct Local : A {};
+
+public:
+  template <typename Init, typename = typename B<Local<Init>::Value>::Type>
+  Arg (Init) {}
+};
+
+class Lambda {
+  static constexpr int Unused = 0;
+    
+public:
+  Lambda (Arg);
+};
+
+// Generated ref to Foo::mfun in the type die of an instantiation of this
+template <void (Foo::*unused)()> struct Callable {};
+
+class I {
+  I() : lamb ([this] {}) {}
+
+  Lambda lamb;
+
+  Callable<&Foo::mfun> bm;
+};