Fix ICE in initialize_inlined_parameters with LTO

[Eric Botcazou]

This is a regression present on the mainline and 6 branch: for the attached 
Ada testcase compiled in LTO mode, the following assertion triggers in 
initialize_inlined_parameters during inlining:

  if (p)
    {
      /* No static chain?  Seems like a bug in tree-nested.c.  */
      gcc_assert (static_chain);

      setup_one_parameter (id, p, static_chain, fn, bb, &vars);
    }

So we have a callee expecting a static chain but the caller doesn't pass one.
It turns out that the caller is a thunk created by the ICF pass (as a wrapper 
in ICF's terminology) so it definitely cannot pass a static chain.  Now ICF 
already makes sure that it doesn't create a wrapper in the opposite situation 
(alias expecting a static chain instead of original function) so the fixlet 
simply makes the test symmetric.

Tested on x86_64-suse-linux, applied on the mainline and 6 branch as obvious.


2016-11-13  Eric Botcazou  <ebotca...@adacore.com>

        * ipa-icf.c (sem_function::merge): Do not create a wrapper also if the
        original function needs a static chain.


2016-11-13  Eric Botcazou  <ebotca...@adacore.com>

        * gnat.dg/lto21.adb: New test.
        * gnat.dg/lto21_pkg1.ads: New helper.
        * gnat.dg/lto21_pkg2.ad[sb]: Likewise.

-- 
Eric Botcazou
Index: ipa-icf.c
===================================================================
--- ipa-icf.c	(revision 242334)
+++ ipa-icf.c	(working copy)
@@ -1186,11 +1186,12 @@ sem_function::merge (sem_item *alias_ite
 	    fprintf (dump_file,
 		     "Wrapper cannot be created because of COMDAT\n");
 	}
-      else if (DECL_STATIC_CHAIN (alias->decl))
+      else if (DECL_STATIC_CHAIN (alias->decl)
+	       || DECL_STATIC_CHAIN (original->decl))
         {
 	  if (dump_file)
 	    fprintf (dump_file,
-		     "Can not create wrapper of nested functions.\n");
+		     "Cannot create wrapper of nested function.\n");
         }
       /* TODO: We can also deal with variadic functions never calling
 	 VA_START.  */

-- { dg-do run }
-- { dg-options "-O3 -flto" { target lto } }

with Lto21_Pkg1;
with Lto21_Pkg2; use Lto21_Pkg2;

procedure Lto21 is
begin
   Proc;
end;

with Ada.Containers.Vectors;
with Lto21_Pkg2;

package Lto21_Pkg1 is

   pragma Suppress (Tampering_Check);

   package Vect1 is new Ada.Containers.Vectors (Positive, Natural);

end Lto21_Pkg1;

with Ada.Containers; use Ada.Containers;
with Ada.Containers.Hashed_Maps;
with Ada.Containers.Vectors;

package body Lto21_Pkg2 is

   pragma Suppress (Tampering_Check);

   procedure Proc is

      function Hash (Syd : Natural) return Hash_Type is (Hash_Type'Mod (Syd));

      package Vect2 is new Vectors (Positive, Natural);

      package Maps is
        new Hashed_Maps (Natural, Vect2.Vector, Hash, "=", Vect2."=");

      procedure Nested (M : Maps.Map) is
         use Maps;
         procedure Inner (Position : Cursor) is null;
      begin
         Iterate (M, Inner'Access);
      end;

      M : Maps.Map;
   begin
      Nested (M);
   end;

end Lto21_Pkg2;

package Lto21_Pkg2 is

   procedure Proc;

end Lto21_Pkg2;