Backport fix for PR c++/85400

[Eric Botcazou]

Jakub asked me to backport the fix for PR c++/85400 initially intended for 
SPARC/Solaris but which also helps on x86-64/Linux apparently.

Tested on the latter platform, applied on the 8 branch.


2019-05-22  Eric Botcazou  <ebotca...@adacore.com>

c-family/
        Backport from mainline
        2018-05-10  Eric Botcazou  <ebotca...@adacore.com>

        PR c++/85400
        * c-attribs.c (handle_visibility_attribute): Do not set no_add_attrs.


2019-05-22  Eric Botcazou  <ebotca...@adacore.com>

cp/
        Backport from mainline
        2018-05-10  Eric Botcazou  <ebotca...@adacore.com>

        PR c++/85400
        * decl2.c (adjust_var_decl_tls_model): New static function.
        (comdat_linkage): Call it on a variable.
        (maybe_make_one_only): Likewise.


2019-05-22  Eric Botcazou  <ebotca...@adacore.com>

        * g++.dg/tls/pr85400.C: New test.

-- 
Eric Botcazou
Index: c-family/c-attribs.c
===================================================================
--- c-family/c-attribs.c	(revision 270883)
+++ c-family/c-attribs.c	(working copy)
@@ -2310,14 +2310,13 @@ handle_visibility_attribute (tree *node,
 
 static tree
 handle_tls_model_attribute (tree *node, tree name, tree args,
-			    int ARG_UNUSED (flags), bool *no_add_attrs)
+			    int ARG_UNUSED (flags),
+			    bool *ARG_UNUSED (no_add_attrs))
 {
   tree id;
   tree decl = *node;
   enum tls_model kind;
 
-  *no_add_attrs = true;
-
   if (!VAR_P (decl) || !DECL_THREAD_LOCAL_P (decl))
     {
       warning (OPT_Wattributes, "%qE attribute ignored", name);
Index: cp/decl2.c
===================================================================
--- cp/decl2.c	(revision 270883)
+++ cp/decl2.c	(working copy)
@@ -1838,6 +1838,17 @@ mark_vtable_entries (tree decl)
     }
 }
 
+/* Adjust the TLS model on variable DECL if need be, typically after
+   the linkage of DECL has been modified.  */
+
+static void
+adjust_var_decl_tls_model (tree decl)
+{
+  if (CP_DECL_THREAD_LOCAL_P (decl)
+      && !lookup_attribute ("tls_model", DECL_ATTRIBUTES (decl)))
+    set_decl_tls_model (decl, decl_default_tls_model (decl));
+}
+
 /* Set DECL up to have the closest approximation of "initialized common"
    linkage available.  */
 
@@ -1888,6 +1899,9 @@ comdat_linkage (tree decl)
 
   if (TREE_PUBLIC (decl))
     DECL_COMDAT (decl) = 1;
+
+  if (VAR_P (decl))
+    adjust_var_decl_tls_model (decl);
 }
 
 /* For win32 we also want to put explicit instantiations in
@@ -1926,6 +1940,8 @@ maybe_make_one_only (tree decl)
 	  /* Mark it needed so we don't forget to emit it.  */
           node->forced_by_abi = true;
 	  TREE_USED (decl) = 1;
+
+	  adjust_var_decl_tls_model (decl);
 	}
     }
 }