coroutines: Handle bad g-r-o-o-a-f cases.

If we see a get_return_object_on_allocation_failure in the
promise, we expect to be able to use it.  If this isn't
possible (because of some error in the declaration) then we
need to handle the erroneous return to allow following code
to complete.

gcc/cp/ChangeLog:

	* coroutines.cc (morph_fn_to_coro): Handle error
	returns in building g-r-o-o-a-f expressions.

gcc/testsuite/ChangeLog:

	* g++.dg/coroutines/coro1-allocators.h (BAD_GROOAF_STATIC):
	New.
	* g++.dg/coroutines/coro-bad-grooaf-00-static.C: New test.

(cherry picked from commit e195c8045a1f3604f0f6b339e9ff731ebd9dcb0e)

diff --git a/gcc/cp/coroutines.cc b/gcc/cp/coroutines.cc
index 736dfb60afb182d229c1dc9148ce4e531363fb5a..192aa0d59972047d576d9dfd67d51c0c3aa10493 100644 (file)
--- a/gcc/cp/coroutines.cc
+++ b/gcc/cp/coroutines.cc
@@ -3943,6 +3943,11 @@ morph_fn_to_coro (tree orig, tree *resumer, tree *destroyer)
                                    NULL_TREE, LOOKUP_NORMAL, NULL,
                                    tf_warning_or_error);
 
+  /* ... but if that fails, returning an error, the later stages can't handle
+     the erroneous expression, so we reset the call as if it was absent.  */
+  if (grooaf == error_mark_node)
+    grooaf = NULL_TREE;
+
   /* Allocate the frame, this has several possibilities:
      n4849 [dcl.fct.def.coroutine] / 9 (part 1)
      The allocation function’s name is looked up in the scope of the promise

diff --git a/gcc/testsuite/g++.dg/coroutines/coro-bad-grooaf-00-static.C b/gcc/testsuite/g++.dg/coroutines/coro-bad-grooaf-00-static.C
new file mode 100644 (file)
index 0000000..e7d0434
--- /dev/null
+++ b/gcc/testsuite/g++.dg/coroutines/coro-bad-grooaf-00-static.C
@@ -0,0 +1,15 @@
+/* g-r-o-o-a-f should be static.  */
+
+#define BAD_GROOAF_STATIC
+#define PROVIDE_GROOAF
+#include "coro1-allocators.h"
+
+int used_grooaf = 0;
+
+struct coro1
+f () noexcept
+{
+  PRINT ("coro1: about to return");
+  co_return;
+} // { dg-error {cannot call member function 'coro1 coro1::promise_type::get_return_object_on_allocation_failure\(\)' without object} }
+

diff --git a/gcc/testsuite/g++.dg/coroutines/coro1-allocators.h b/gcc/testsuite/g++.dg/coroutines/coro1-allocators.h
index 3d86910600608cc3612acc9de07723ca9cd3bc5f..f7a85e9e671d5cc1093c51eb878248b6c6f36a25 100644 (file)
--- a/gcc/testsuite/g++.dg/coroutines/coro1-allocators.h
+++ b/gcc/testsuite/g++.dg/coroutines/coro1-allocators.h
@@ -172,8 +172,11 @@ struct coro1 {
   }
 #endif
 
+#ifndef BAD_GROOAF_STATIC
+# define BAD_GROOAF_STATIC static
+#endif
 #ifdef PROVIDE_GROOAF
-  static coro1 get_return_object_on_allocation_failure () noexcept {
+  BAD_GROOAF_STATIC coro1 get_return_object_on_allocation_failure () noexcept {
     PRINT ("alloc fail return");
     used_grooaf++;
     return coro1 (nullptr);