c++, coroutines: Fix block nests when the function has no top-level bind.

When the function contains no local vars and also no nested scopes, there
is no top-level bind expression.  Because the rewritten coroutine body will
require both local vars and contain nested scopes, we add a bind expression
to such functions.  When this was done the necessary scope blocks were
omitted which leads to disconnected function content.

Fixed by adding a new block to the added bind expression.

Signed-off-by: Iain Sandoe <iain@sandoe.co.uk>
gcc/cp/ChangeLog:

	* coroutines.cc (coro_rewrite_function_body): Ensure that added
	bind expressions have scope blocks.

(cherry picked from commit a8d7631d333c22e38a067d32d11fd2b60cf1d960)

diff --git a/gcc/cp/coroutines.cc b/gcc/cp/coroutines.cc
index 03ba3f6aa262c18dfa36386e43fa87d766d5d480..85a760d8220112d25a0be378848fa36590701e4a 100644 (file)
--- a/gcc/cp/coroutines.cc
+++ b/gcc/cp/coroutines.cc
@@ -4109,6 +4109,10 @@ coro_rewrite_function_body (location_t fn_start, tree fnbody, tree orig,
       tree bind_wrap = build3_loc (fn_start, BIND_EXPR, void_type_node,
                                   NULL, NULL, NULL);
       BIND_EXPR_BODY (bind_wrap) = fnbody;
+      /* Ensure we have a block to connect up the scopes.  */
+      tree new_blk = make_node (BLOCK);
+      BIND_EXPR_BLOCK (bind_wrap) = new_blk;
+      BLOCK_SUBBLOCKS (top_block) = new_blk;
       fnbody = bind_wrap;
     }