[PATCH] Fix PR86654

[Richard Biener <rguenther@suse.de>]

I am testing the following patch to avoid forcing DIEs for a type context
for method clones late via limbo processing.  Instead hang them off
comp_unit_die if there is no early DIE for the function.

One question is whether the comment "If we're a nested function"
matches up with the decl_function_context (decl) check or whether
we really wanted to check DECL_CONTEXT (decl) == FUNCTION_DECL
which would have made this particular case not match (DECL_CONTEXT
is a RECORD_TYPE which context is a FUNCTION_DECL).

Another option is of course to make clones not inherit
DECL_CONTEXT from the cloned function (for an artificial
instance the "context" is somewhat arbitrary since it isn't
going to be found by lookup).  In fact I long wanted to
represent clones as artificial containers for an
inline instance of the cloned function...

LTO bootstrap and regtest running on x86_64-unknown-linux-gnu.

If that succeeds I'm going to apply it as a stop-gap measure to
make Firefox build again with LTO but I'm open to revising it.

Richard.

2018-07-24  Richard Biener  <rguenther@suse.de>

	PR debug/86654
	* dwarf2out.c (dwarf2out_decl): Do not handle nested functions
	special wrt context_die late.

Index: gcc/dwarf2out.c
===================================================================
--- gcc/dwarf2out.c	(revision 262948)
+++ gcc/dwarf2out.c	(working copy)
@@ -26702,8 +26702,11 @@ dwarf2out_decl (tree decl)
     case FUNCTION_DECL:
       /* If we're a nested function, initially use a parent of NULL; if we're
 	 a plain function, this will be fixed up in decls_for_scope.  If
-	 we're a method, it will be ignored, since we already have a DIE.  */
-      if (decl_function_context (decl)
+	 we're a method, it will be ignored, since we already have a DIE.
+	 Avoid doing this late though since clones of class methods may
+	 otherwise end up creating type DIEs late.  */
+      if (early_dwarf
+	  && decl_function_context (decl)
 	  /* But if we're in terse mode, we don't care about scope.  */
 	  && debug_info_level > DINFO_LEVEL_TERSE)
 	context_die = NULL;