support aliases and trampolines in dwarf2

for  gcc/ChangeLog

	* debug.h (struct gcc_debug_hooks): Add aliased_decl and
	trampoline_decl.
	* dwarf2out.c (dwarf2out_aliased_decl): New.
	(dwarf2out_trampoline_decl): New.
	(dwarf2_debug_hooks): Add them.
	(dwarf2_name): Skip leading '*' returned by langhook.
	(dwarf2_lineno_debug_hooks): Add dummies.
	* debug.c (do_nothing_debug_hooks): Likewise.
	* dbxout.c (dbx_debug_hooks, xcoff_debug_hooks): Likewise.
	* sdbout.c (sdb_debug_hooks): Likewise.
	* vmsdbgout.c (vmsdbg_debug_hooks): Likewise.
	* cgraph.h (cgraph_node::is_lang_trampoline): Declare.
	* cgraphunit.c: Include demangle.h.
	(cgraph_node::expand_thunk): Call function_decl debug_hook
	after assembly expansion.  Do not mark thunk as ignored in
	gimple expansion.
	(cxx_cdtor_trampoline_p): New.
	(cgraph_node::is_lang_trampoline): New.
	(cgraph_node::assemble_thunks_and_aliases): Call the new
	debug_hooks.
	(symbol_table::output_weakrefs): Likewise.
	* varpool.c (varpool_node::assemble_aliases): Likewise.

for  gcc/cp/ChangeLog

	* method.c (make_alias_for): Copy DECL_IGNORED_P.

for  gcc/testsuite/ChangeLog

	* g++.dg/debug/dwarf2/cdtor-1.C: Adjust linkage_name count.
	* g++.dg/debug/dwarf2/cdtor-2.C: New.
	* g++.dg/debug/dwarf2/cdtor-3.C: New.
	* g++.dg/debug/dwarf2/covariant-1.C: New.
	* gcc.dg/debug/dwarf2/attr-alias-1.c: New.
	* gcc.dg/debug/dwarf2/attr-alias-2.c: New.
	* gcc.dg/debug/dwarf2/attr-weakref-1.c: New.
	* gcc.dg/debug/dwarf2/attr-weakref-2.c: New.

18 files changed, 349 insertions, 12 deletions

diff --git a/gcc/cgraph.h b/gcc/cgraph.h
index fc7bb223484..4d8bf05c1df 100644
--- a/gcc/cgraph.h
+++ b/gcc/cgraph.h
@@ -1117,6 +1117,10 @@ public:
      external means.  */
   inline void mark_force_output (void);
 
+  /* Return true when function is a language-defined trampoline, e.g.,
+     C++ ctor and dtor "thunks" that just call the unified cdtor.  */
+  bool is_lang_trampoline (void);
+
   /* Return true when function can be marked local.  */
   bool local_p (void);
 
diff --git a/gcc/cgraphunit.c b/gcc/cgraphunit.c
index 0a745f0f473..b399d61d079 100644
--- a/gcc/cgraphunit.c
+++ b/gcc/cgraphunit.c
@@ -203,6 +203,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "dbgcnt.h"
 #include "tree-chkp.h"
 #include "lto-section-names.h"
+#include "demangle.h"
 
 /* Queue of cgraph nodes scheduled to be added into cgraph.  This is a
    secondary queue used during optimization to accommodate passes that
@@ -1635,6 +1636,12 @@ cgraph_node::expand_thunk (bool output_asm_thunks, bool force_gimple_thunk)
       assemble_end_function (thunk_fndecl, fnname);
       insn_locations_finalize ();
       init_insn_lengths ();
+
+      timevar_push (TV_SYMOUT);
+      if (!DECL_IGNORED_P (thunk_fndecl))
+	(*debug_hooks->function_decl) (thunk_fndecl);
+      timevar_pop (TV_SYMOUT);
+
       free_after_compilation (cfun);
       TREE_ASM_WRITTEN (thunk_fndecl) = 1;
       thunk.thunk_p = false;
@@ -1676,7 +1683,6 @@ cgraph_node::expand_thunk (bool output_asm_thunks, bool force_gimple_thunk)
       resolve_unique_section (thunk_fndecl, 0,
 			      flag_function_sections);
 
-      DECL_IGNORED_P (thunk_fndecl) = 1;
       bitmap_obstack_initialize (NULL);
 
       if (thunk.virtual_offset_p)
@@ -1889,6 +1895,92 @@ cgraph_node::expand_thunk (bool output_asm_thunks, bool force_gimple_thunk)
   return true;
 }
 
+/* Return true if DECL is a cdtor trampoline for unified cdtor
+   TARGET.  */
+
+static bool
+cxx_cdtor_trampoline_p (tree decl, tree target)
+{
+  if (DECL_ABSTRACT_ORIGIN (decl))
+    return false;
+
+  if (!DECL_CXX_CONSTRUCTOR_P (decl) && !DECL_CXX_DESTRUCTOR_P (decl))
+    return false;
+
+  if (DECL_CXX_CONSTRUCTOR_P (decl) != DECL_CXX_CONSTRUCTOR_P (target))
+    return false;
+
+  if (DECL_CXX_DESTRUCTOR_P (decl) != DECL_CXX_DESTRUCTOR_P (target))
+    return false;
+
+  gcc_assert (DECL_ASSEMBLER_NAME_SET_P (decl));
+  gcc_assert (DECL_ASSEMBLER_NAME_SET_P (target));
+
+  const char *dname = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
+  const char *tname = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (target));
+
+  unsigned int i = strlen (dname);
+  if (i != strlen (tname))
+    return false;
+
+  gcc_assert (i);
+
+  /* C1 and C2 ctors may be trampolines to C4; D0, D1 and D2 dtors may
+     be trampolines to D4.  Check their mangled names, so that the
+     test will work even during LTO compilations, when the cdtor
+     clones retrofitted into trampolines might not be right after the
+     unified one in the DECL_CHAIN, and we don't have C++-specific
+     data structures or lang hooks to check that the cdtors are of
+     different kinds and belong to the same class.
+
+     Alas, just checking that the assembler name has e.g. C2 vs C4 as
+     the only difference could find false positives, e.g., if there
+     are cdtors with the same signature (aside from the THIS pointer)
+     in classes whose names contain C2 and C4, say _ZN2C2C1Ev AKA
+     C2::C2() and _ZN2C4C1Ev AKA C4::C4().
+
+     So, after checking that we found viable distinguishing characters
+     at the expected place, we check that the cdtors are of different
+     kinds using the demangler.  Yuck.  */
+  bool found = false;
+  while (i--)
+    if (dname[i] != tname[i])
+      {
+	if (!found
+	    && tname[i] == '4' && i && tname[i-1] == dname[i-1]
+	    && (((dname[i-1] == 'C' || dname[i-1] == 'D')
+		 && (dname[i] == '1' || dname[i] == '2'))
+		|| (dname[i-1] == 'D' && dname[i] == '0')))
+	  found = true;
+	else
+	  return false;
+      }
+
+  if (DECL_CXX_CONSTRUCTOR_P (decl))
+    return is_gnu_v3_mangled_ctor (tname) == gnu_v3_unified_ctor
+      && is_gnu_v3_mangled_ctor (dname) != gnu_v3_unified_ctor;
+  else if (DECL_CXX_DESTRUCTOR_P (decl))
+    return is_gnu_v3_mangled_dtor (tname) == gnu_v3_unified_dtor
+      && is_gnu_v3_mangled_dtor (dname) != gnu_v3_unified_dtor;
+  else
+    gcc_unreachable ();
+}
+
+/* Return true when function is as a language-defined trampoline,
+   e.g., C++ ctor and dtor "thunks" that just call the unified
+   cdtor.  */
+
+bool
+cgraph_node::is_lang_trampoline (void)
+{
+  if (!callees || callees->next_callee)
+    return false;
+
+  tree target = callees->callee->decl;
+
+  return (cxx_cdtor_trampoline_p (decl, target));
+}
+
 /* Assemble thunks and aliases associated to node.  */
 
 void
@@ -1906,9 +1998,17 @@ cgraph_node::assemble_thunks_and_aliases (void)
 	e = e->next_caller;
 	thunk->expand_thunk (true, false);
 	thunk->assemble_thunks_and_aliases ();
+	if (!DECL_IGNORED_P (thunk->decl) && !DECL_IGNORED_P (decl))
+	  (*debug_hooks->trampoline_decl) (thunk->decl, decl);
       }
     else
-      e = e->next_caller;
+      {
+	if (e->caller->is_lang_trampoline ()
+	    && !DECL_IGNORED_P (e->caller->decl) && !DECL_IGNORED_P (decl))
+	  (*debug_hooks->trampoline_decl) (e->caller->decl, decl);
+
+	e = e->next_caller;
+      }
 
   FOR_EACH_ALIAS (this, ref)
     {
@@ -1922,6 +2022,8 @@ cgraph_node::assemble_thunks_and_aliases (void)
 	  TREE_ASM_WRITTEN (decl) = 1;
 	  do_assemble_alias (alias->decl,
 			     DECL_ASSEMBLER_NAME (decl));
+	  if (!DECL_IGNORED_P (alias->decl) && !DECL_IGNORED_P (decl))
+	    (*debug_hooks->aliased_decl) (alias->decl, decl);
 	  alias->assemble_thunks_and_aliases ();
 	  TREE_ASM_WRITTEN (decl) = saved_written;
 	}
@@ -2341,7 +2443,7 @@ symbol_table::output_weakrefs (void)
 	    || !TREE_ASM_WRITTEN (cnode->instrumented_version->decl))
 	&& node->weakref)
       {
-	tree target;
+	tree target, target_decl;
 
 	/* Weakrefs are special by not requiring target definition in current
 	   compilation unit.  It is thus bit hard to work out what we want to
@@ -2349,17 +2451,33 @@ symbol_table::output_weakrefs (void)
 	   When alias target is defined, we need to fetch it from symtab reference,
 	   otherwise it is pointed to by alias_target.  */
 	if (node->alias_target)
-	  target = (DECL_P (node->alias_target)
-		    ? DECL_ASSEMBLER_NAME (node->alias_target)
-		    : node->alias_target);
+	  {
+	    if (DECL_P (node->alias_target))
+	      {
+		target_decl = node->alias_target;
+		target = DECL_ASSEMBLER_NAME (target_decl);
+	      }
+	    else
+	      {
+		target_decl = NULL_TREE;
+		target = node->alias_target;
+	      }
+	  }
 	else if (node->analyzed)
-	  target = DECL_ASSEMBLER_NAME (node->get_alias_target ()->decl);
+	  {
+	    target_decl = node->get_alias_target ()->decl;
+	    target = DECL_ASSEMBLER_NAME (target_decl);
+	  }
 	else
 	  {
 	    gcc_unreachable ();
-	    target = get_alias_symbol (node->decl);
+	    target_decl = node->decl;
+	    target = get_alias_symbol (target_decl);
 	  }
         do_assemble_alias (node->decl, target);
+	if (target_decl && !DECL_IGNORED_P (node->decl)
+	    && !DECL_IGNORED_P (target_decl))
+	  (*debug_hooks->aliased_decl) (node->decl, target_decl);
       }
 }
 
diff --git a/gcc/cp/method.c b/gcc/cp/method.c
index f455b32e2a0..9bbe0c85f49 100644
--- a/gcc/cp/method.c
+++ b/gcc/cp/method.c
@@ -219,6 +219,7 @@ make_alias_for (tree target, tree newid)
     }
   DECL_EXTERNAL (alias) = 0;
   DECL_ARTIFICIAL (alias) = 1;
+  DECL_IGNORED_P (alias) = DECL_IGNORED_P (target);
   DECL_TEMPLATE_INSTANTIATED (alias) = 0;
   if (TREE_CODE (alias) == FUNCTION_DECL)
     {
diff --git a/gcc/dbxout.c b/gcc/dbxout.c
index 25a03ef70a3..8da8eb05fb3 100644
--- a/gcc/dbxout.c
+++ b/gcc/dbxout.c
@@ -372,6 +372,8 @@ const struct gcc_debug_hooks dbx_debug_hooks =
   debug_nothing_tree_tree_tree_bool,	 /* imported_module_or_decl */
   debug_nothing_tree,		         /* deferred_inline_function */
   debug_nothing_tree,		         /* outlining_inline_function */
+  debug_nothing_tree_tree,		 /* aliased_decl */
+  debug_nothing_tree_tree,		 /* trampoline_decl */
   debug_nothing_rtx_code_label,	         /* label */
   dbxout_handle_pch,		         /* handle_pch */
   debug_nothing_rtx_insn,	         /* var_location */
@@ -412,6 +414,8 @@ const struct gcc_debug_hooks xcoff_debug_hooks =
   debug_nothing_tree_tree_tree_bool,	 /* imported_module_or_decl */
   debug_nothing_tree,		         /* deferred_inline_function */
   debug_nothing_tree,		         /* outlining_inline_function */
+  debug_nothing_tree_tree,		 /* aliased_decl */
+  debug_nothing_tree_tree,		 /* trampoline_decl */
   debug_nothing_rtx_code_label,	         /* label */
   dbxout_handle_pch,		         /* handle_pch */
   debug_nothing_rtx_insn,	         /* var_location */
diff --git a/gcc/debug.c b/gcc/debug.c
index 9c2caaea695..c9495c9a27c 100644
--- a/gcc/debug.c
+++ b/gcc/debug.c
@@ -50,6 +50,8 @@ const struct gcc_debug_hooks do_nothing_debug_hooks =
   debug_nothing_tree_tree_tree_bool,	 /* imported_module_or_decl */
   debug_nothing_tree,		         /* deferred_inline_function */
   debug_nothing_tree,		         /* outlining_inline_function */
+  debug_nothing_tree_tree,		 /* aliased_decl */
+  debug_nothing_tree_tree,		 /* trampoline_decl */
   debug_nothing_rtx_code_label,	         /* label */
   debug_nothing_int,		         /* handle_pch */
   debug_nothing_rtx_insn,	         /* var_location */
diff --git a/gcc/debug.h b/gcc/debug.h
index 6711f8bd620..cb6218f5d1d 100644
--- a/gcc/debug.h
+++ b/gcc/debug.h
@@ -155,6 +155,14 @@ struct gcc_debug_hooks
      the inline before it gets mangled by optimization.  */
   void (* outlining_inline_function) (tree decl);
 
+  /* ALIAS is a declaration whose symbol was defined as an alias to
+     DECL's symbol.  Called right after outputting the alias
+     definition.  */
+  void (* aliased_decl) (tree alias, tree decl);
+
+  /* TRAMPOLINE is a function defined as a trampoline to DECL.  */
+  void (* trampoline_decl) (tree trampoline, tree decl);
+
   /* Called from final_scan_insn for any CODE_LABEL insn whose
      LABEL_NAME is non-null.  */
   void (* label) (rtx_code_label *);
diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index d8ca1b7e6ba..cba37f98a1f 100644
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -2506,6 +2506,8 @@ static void dwarf2out_begin_function (tree);
 static void dwarf2out_end_function (unsigned int);
 static void dwarf2out_register_main_translation_unit (tree unit);
 static void dwarf2out_set_name (tree, tree);
+static void dwarf2out_aliased_decl (tree, tree);
+static void dwarf2out_trampoline_decl (tree, tree);
 
 /* The debug hooks structure.  */
 
@@ -2545,6 +2547,8 @@ const struct gcc_debug_hooks dwarf2_debug_hooks =
      emitting the abstract description of inline functions until
      something tries to reference them.  */
   dwarf2out_abstract_function,	/* outlining_inline_function */
+  dwarf2out_aliased_decl,	/* aliased_decl */
+  dwarf2out_trampoline_decl,	/* trampoline_decl */
   debug_nothing_rtx_code_label,	/* label */
   debug_nothing_int,		/* handle_pch */
   dwarf2out_var_location,
@@ -2583,6 +2587,8 @@ const struct gcc_debug_hooks dwarf2_lineno_debug_hooks =
   debug_nothing_tree_tree_tree_bool,	 /* imported_module_or_decl */
   debug_nothing_tree,		         /* deferred_inline_function */
   debug_nothing_tree,		         /* outlining_inline_function */
+  debug_nothing_tree_tree,		 /* aliased_decl */
+  debug_nothing_tree_tree,		 /* trampoline_decl */
   debug_nothing_rtx_code_label,	         /* label */
   debug_nothing_int,		         /* handle_pch */
   debug_nothing_rtx_insn,	         /* var_location */
@@ -9755,7 +9761,10 @@ dwarf2_name (tree decl, int scope)
 {
   if (DECL_NAMELESS (decl))
     return NULL;
-  return lang_hooks.dwarf_name (decl, scope ? 1 : 0);
+  const char *name = lang_hooks.dwarf_name (decl, scope ? 1 : 0);
+  if (name && name[0] == '*')
+    name++;
+  return name;
 }
 
 /* Add a new entry to .debug_pubnames if appropriate.  */
@@ -23797,6 +23806,95 @@ dwarf2out_imported_module_or_decl (tree decl, tree name, tree context,
   dwarf2out_imported_module_or_decl_1 (decl, name, context, scope_die);
 }
 
+/* Output debug info indicating that ALIAS is an alias to DECL.  */
+
+static void
+dwarf2out_aliased_decl (tree alias, tree decl)
+{
+  if (debug_info_level <= DINFO_LEVEL_TERSE)
+    return;
+
+  if (!(dwarf_version >= 3 || !dwarf_strict))
+    return;
+
+  if (DECL_IGNORED_P (decl) || DECL_IGNORED_P (alias))
+    return;
+
+  dw_die_ref decl_die = lookup_decl_die (decl);
+
+  if (!decl_die)
+    return;
+
+  dw_die_ref old_alias_die = lookup_decl_die (alias);
+
+  if (old_alias_die && TREE_CODE (alias) == FUNCTION_DECL)
+    /* FIXME: we have a specification and probably a definition that
+       turned into an alias.  Location information of the aliased
+       definition is most certainly not suitable for this alias.  */
+    return;
+
+  dw_die_ref alias_die = new_die (DW_TAG_imported_declaration,
+				  comp_unit_die (), NULL_TREE);
+
+  add_AT_die_ref (alias_die, DW_AT_import, decl_die);
+
+  /* ??? It would be nice if we could just link back to the symbol
+     declaration, but DW_AT_specification is not a welcome attribute
+     for a DW_TAG_imported_declaration.  */
+  if (0 && old_alias_die)
+    {
+      add_AT_die_ref (alias_die, DW_AT_specification, old_alias_die);
+      return;
+    }
+
+  equate_decl_number_to_die (alias, alias_die);
+
+  if (TREE_PUBLIC (alias))
+    add_AT_flag (alias_die, DW_AT_external, 1);
+
+  {
+    bool save_artificial = DECL_ARTIFICIAL (alias);
+    /* Temporarily set DECL_ARTIFICIAL so that we don't emit src coords
+       attributes.  */
+    DECL_ARTIFICIAL (alias) = true;
+    add_name_and_src_coords_attributes (alias_die, alias);
+    DECL_ARTIFICIAL (alias) = save_artificial;
+  }
+
+  add_pubname (alias, alias_die);
+  if (DECL_ARTIFICIAL (alias))
+    add_AT_flag (alias_die, DW_AT_artificial, 1);
+  add_accessibility_attribute (alias_die, alias);
+}
+
+/* Output debug info indicating that TRAMPOLINE is a trampoline to
+   DECL.  */
+
+static void
+dwarf2out_trampoline_decl (tree trampoline, tree decl)
+{
+  if (debug_info_level <= DINFO_LEVEL_TERSE)
+    return;
+
+  if (!(dwarf_version >= 3 || !dwarf_strict))
+    return;
+
+  if (DECL_IGNORED_P (decl) || DECL_IGNORED_P (trampoline))
+    return;
+
+  dw_die_ref decl_die = lookup_decl_die (decl);
+
+  if (!decl_die)
+    return;
+
+  dw_die_ref trampoline_die = lookup_decl_die (trampoline);
+
+  if (!trampoline_die)
+    return;
+
+  add_AT_die_ref (trampoline_die, DW_AT_trampoline, decl_die);
+}
+
 /* Output debug information for namelists.   */
 
 static dw_die_ref
diff --git a/gcc/sdbout.c b/gcc/sdbout.c
index dc52716391e..df26ad80781 100644
--- a/gcc/sdbout.c
+++ b/gcc/sdbout.c
@@ -301,6 +301,8 @@ const struct gcc_debug_hooks sdb_debug_hooks =
   debug_nothing_tree_tree_tree_bool,	 /* imported_module_or_decl */
   debug_nothing_tree,		         /* deferred_inline_function */
   debug_nothing_tree,		         /* outlining_inline_function */
+  debug_nothing_tree_tree,		 /* aliased_decl */
+  debug_nothing_tree_tree,		 /* trampoline_decl */
   sdbout_label,			         /* label */
   debug_nothing_int,		         /* handle_pch */
   debug_nothing_rtx_insn,	         /* var_location */
diff --git a/gcc/testsuite/g++.dg/debug/dwarf2/cdtor-1.C b/gcc/testsuite/g++.dg/debug/dwarf2/cdtor-1.C
index c0d3d225187..71efae87013 100644
--- a/gcc/testsuite/g++.dg/debug/dwarf2/cdtor-1.C
+++ b/gcc/testsuite/g++.dg/debug/dwarf2/cdtor-1.C
@@ -14,4 +14,4 @@ main()
   K k;
 }
 
-// { dg-final {scan-assembler-times " DW_AT_\[MIPS_\]*linkage_name" 4 } }
+// { dg-final {scan-assembler-times " DW_AT_\[MIPS_\]*linkage_name" 6 } }
diff --git a/gcc/testsuite/g++.dg/debug/dwarf2/cdtor-2.C b/gcc/testsuite/g++.dg/debug/dwarf2/cdtor-2.C
new file mode 100644
index 00000000000..0737e432503
--- /dev/null
+++ b/gcc/testsuite/g++.dg/debug/dwarf2/cdtor-2.C
@@ -0,0 +1,13 @@
+// { dg-options "-gdwarf-2 -dA" }
+/* { dg-require-alias "" } */
+// { dg-do compile }
+
+struct foo {
+  foo ();
+  ~foo ();
+};
+
+foo::foo () {}
+foo::~foo () {}
+
+// { dg-final { scan-assembler-times " DW_AT_import" 2 } }
diff --git a/gcc/testsuite/g++.dg/debug/dwarf2/cdtor-3.C b/gcc/testsuite/g++.dg/debug/dwarf2/cdtor-3.C
new file mode 100644
index 00000000000..d500e828886
--- /dev/null
+++ b/gcc/testsuite/g++.dg/debug/dwarf2/cdtor-3.C
@@ -0,0 +1,17 @@
+// { dg-options "-gdwarf-2 -fdeclone-ctor-dtor -dA" }
+// { dg-do compile }
+
+struct bar {
+  bar ();
+  ~bar ();
+};
+
+struct foo : virtual bar {
+  foo ();
+  ~foo ();
+};
+
+foo::foo () {}
+foo::~foo () {}
+
+// { dg-final { scan-assembler-times " DW_AT_trampoline" 4 } }
diff --git a/gcc/testsuite/g++.dg/debug/dwarf2/covariant-1.C b/gcc/testsuite/g++.dg/debug/dwarf2/covariant-1.C
new file mode 100644
index 00000000000..1f4326aecfe
--- /dev/null
+++ b/gcc/testsuite/g++.dg/debug/dwarf2/covariant-1.C
@@ -0,0 +1,24 @@
+// { dg-options "-gdwarf-2 -dA" }
+/* { dg-require-alias "" } */
+// { dg-do compile }
+
+class A {
+public:
+  virtual A* getThis();
+};
+
+class B {
+  int a;
+public:
+  virtual B* getThis();
+};
+
+class AB : public A, public B {
+public:
+  virtual AB* getThis();
+};
+
+AB* AB::getThis() { return this; }
+
+// { dg-final { scan-assembler-times " DW_AT_import" 2 } }
+// { dg-final { scan-assembler-times " DW_AT_trampoline" 1 } }
diff --git a/gcc/testsuite/gcc.dg/debug/dwarf2/attr-alias-1.c b/gcc/testsuite/gcc.dg/debug/dwarf2/attr-alias-1.c
new file mode 100644
index 00000000000..9968856fd69
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/debug/dwarf2/attr-alias-1.c
@@ -0,0 +1,10 @@
+/* { dg-do compile } */
+/* { dg-require-alias "" } */
+/* { dg-options "-gdwarf-2 -dA" } */
+
+static int f1 (void) { return 0; }
+extern int g1 (void) __attribute__((__alias__("f1")));
+
+int f () { return g1 (); }
+
+// { dg-final { scan-assembler-times " DW_AT_import" 1 } }
diff --git a/gcc/testsuite/gcc.dg/debug/dwarf2/attr-alias-2.c b/gcc/testsuite/gcc.dg/debug/dwarf2/attr-alias-2.c
new file mode 100644
index 00000000000..27201d4ad09
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/debug/dwarf2/attr-alias-2.c
@@ -0,0 +1,10 @@
+/* { dg-do compile } */
+/* { dg-require-alias "" } */
+/* { dg-options "-gdwarf-2 -dA" } */
+
+static int i1 = 0;
+extern int i2 __attribute__((__alias__("i1")));
+
+int f () { return i2; }
+
+// { dg-final { scan-assembler-times " DW_AT_import" 1 } }
diff --git a/gcc/testsuite/gcc.dg/debug/dwarf2/attr-weakref-1.c b/gcc/testsuite/gcc.dg/debug/dwarf2/attr-weakref-1.c
new file mode 100644
index 00000000000..b53bd05f44f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/debug/dwarf2/attr-weakref-1.c
@@ -0,0 +1,10 @@
+/* { dg-do compile } */
+/* { dg-require-weak "" } */
+/* { dg-options "-gdwarf-2 -dA" } */
+
+int f1 (void) { return 0; }
+static int g1 (void) __attribute__((__weakref__("f1")));
+
+int f () { return g1 (); }
+
+// { dg-final { scan-assembler-times " DW_AT_import" 1 } }
diff --git a/gcc/testsuite/gcc.dg/debug/dwarf2/attr-weakref-2.c b/gcc/testsuite/gcc.dg/debug/dwarf2/attr-weakref-2.c
new file mode 100644
index 00000000000..60202022776
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/debug/dwarf2/attr-weakref-2.c
@@ -0,0 +1,10 @@
+/* { dg-do compile } */
+/* { dg-require-weak "" } */
+/* { dg-options "-gdwarf-2 -dA" } */
+
+int i1 = 0;
+static int i2 __attribute__((__weakref__("i1")));
+
+int f () { return i2; }
+
+// { dg-final { scan-assembler-times " DW_AT_import" 1 } }
diff --git a/gcc/varpool.c b/gcc/varpool.c
index cbbdda41369..878aaee13ae 100644
--- a/gcc/varpool.c
+++ b/gcc/varpool.c
@@ -538,8 +538,12 @@ varpool_node::assemble_aliases (void)
     {
       varpool_node *alias = dyn_cast <varpool_node *> (ref->referring);
       if (!alias->transparent_alias)
-	do_assemble_alias (alias->decl,
-			   DECL_ASSEMBLER_NAME (decl));
+	{
+	  do_assemble_alias (alias->decl,
+			     DECL_ASSEMBLER_NAME (decl));
+	  if (!DECL_IGNORED_P (alias->decl) && !DECL_IGNORED_P (decl))
+	    (*debug_hooks->aliased_decl) (alias->decl, decl);
+	}
       alias->assemble_aliases ();
     }
 }
diff --git a/gcc/vmsdbgout.c b/gcc/vmsdbgout.c
index 7c6d64dc793..fc87828292c 100644
--- a/gcc/vmsdbgout.c
+++ b/gcc/vmsdbgout.c
@@ -198,6 +198,8 @@ const struct gcc_debug_hooks vmsdbg_debug_hooks
    debug_nothing_tree_tree_tree_bool, /* imported_module_or_decl */
    debug_nothing_tree,		  /* deferred_inline_function */
    vmsdbgout_abstract_function,
+   debug_nothing_tree_tree,	  /* aliased_decl */
+   debug_nothing_tree_tree,	  /* trampoline_decl */
    debug_nothing_rtx_code_label,  /* label */
    debug_nothing_int,		  /* handle_pch */
    debug_nothing_rtx_insn,	  /* var_location */