c++: Fix up push_local_extern_decl_alias error recovery [PR102642]

My recent push_local_extern_decl_alias change broke error-recovery,
do_pushdecl can return error_mark_node and set_decl_tls_model can't be
called on that.  There are other code paths that store error_mark_node
into DECL_LOCAL_DECL_ALIAS, with the intent to differentiate the cases
where we haven't yet tried to push it into the namespace scope (NULL)
and one where we have tried it but it failed (error_mark_node), but looking
around, there are other spots where we call functions or do processing
which doesn't tolerate error_mark_node.

So, the first hunk with the testcase fixes the testcase, the others
fix what I've spotted and the fix was easy to figure out (there are I think
3 other spots mainly for function multiversioning).

2021-10-20  Jakub Jelinek  <jakub@redhat.com>

	PR c++/102642
	* name-lookup.c (push_local_extern_decl_alias): Don't call
	set_decl_tls_model on error_mark_node.
	* decl.c (make_rtl_for_nonlocal_decl): Don't call
	set_user_assembler_name on error_mark_node.
	* parser.c (cp_parser_oacc_declare): Ignore DECL_LOCAL_DECL_ALIAS
	if it is error_mark_node.
	(cp_parser_omp_declare_target): Likewise.

	* g++.dg/tls/pr102642.C: New test.

diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 242429d9ef4a2a95ce1b6a368fd1833cb5062f2e..8a45411c995d047aa9e13bf34076a1b0ff77e22c 100644 (file)
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -7373,7 +7373,8 @@ make_rtl_for_nonlocal_decl (tree decl, tree init, const char* asmspec)
                 This is horrible, as we're affecting a
                 possibly-shared decl.  Again, a one-true-decl
                 model breaks down.  */
-             set_user_assembler_name (ns_decl, asmspec);
+             if (ns_decl != error_mark_node)
+               set_user_assembler_name (ns_decl, asmspec);
        }
     }
 

diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
index c414a1091b449826a91188667dc58932281c715d..035bcf51278cb99f357c8c72d3305f7ae83bfeaf 100644 (file)
--- a/gcc/cp/name-lookup.c
+++ b/gcc/cp/name-lookup.c
@@ -3474,7 +3474,9 @@ push_local_extern_decl_alias (tree decl)
          push_nested_namespace (ns);
          alias = do_pushdecl (alias, /* hiding= */true);
          pop_nested_namespace (ns);
-         if (VAR_P (decl) && CP_DECL_THREAD_LOCAL_P (decl))
+         if (VAR_P (decl)
+             && CP_DECL_THREAD_LOCAL_P (decl)
+             && alias != error_mark_node)
            set_decl_tls_model (alias, DECL_TLS_MODEL (decl));
        }
     }

diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 865778e4d301e9a6e97f3abed8a99498ecdc7331..9c7ed65f55c8a6388bd00d83d9ca745fe415092f 100644 (file)
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -44437,7 +44437,8 @@ cp_parser_oacc_declare (cp_parser *parser, cp_token *pragma_tok)
               dependent local extern variable decls are as rare as
               hen's teeth.  */
            if (auto alias = DECL_LOCAL_DECL_ALIAS (decl))
-             decl = alias;
+             if (alias != error_mark_node)
+               decl = alias;
 
          if (OMP_CLAUSE_MAP_KIND (t) == GOMP_MAP_LINK)
            id = get_identifier ("omp declare target link");
@@ -45665,7 +45666,8 @@ cp_parser_omp_declare_target (cp_parser *parser, cp_token *pragma_tok)
       if (VAR_OR_FUNCTION_DECL_P (t)
          && DECL_LOCAL_DECL_P (t)
          && DECL_LANG_SPECIFIC (t)
-         && DECL_LOCAL_DECL_ALIAS (t))
+         && DECL_LOCAL_DECL_ALIAS (t)
+         && DECL_LOCAL_DECL_ALIAS (t) != error_mark_node)
        handle_omp_declare_target_clause (c, DECL_LOCAL_DECL_ALIAS (t),
                                          device_type);
     }

diff --git a/gcc/testsuite/g++.dg/tls/pr102642.C b/gcc/testsuite/g++.dg/tls/pr102642.C
new file mode 100644 (file)
index 0000000..e3236d3
--- /dev/null
+++ b/gcc/testsuite/g++.dg/tls/pr102642.C
@@ -0,0 +1,10 @@
+// PR c++/102642
+// { dg-do compile { target c++11 } }
+
+thread_local int *z;           // { dg-message "previous declaration" }
+
+void
+foo ()
+{
+  extern thread_local int z;   // { dg-error "conflicting declaration" }
+}