[committed 02/12] d: Drop any field or parameter types that got cached before conversion failed.

[Iain Buclaw via Gcc-patches]

This ensures there are no dangling references to AST members that have
been freed, either explcitly or by the garbage collector.

gcc/d/ChangeLog:

        * d-builtins.cc (build_frontend_type): Restore builtin_converted_decls
        length on conversion failure.
---
 gcc/d/d-builtins.cc | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/gcc/d/d-builtins.cc b/gcc/d/d-builtins.cc
index ff2a5776dc5..9db46c0c5ca 100644
--- a/gcc/d/d-builtins.cc
+++ b/gcc/d/d-builtins.cc
@@ -80,7 +80,8 @@ build_frontend_type (tree type)
     mod |= MODshared;
 
   /* If we've seen the type before, re-use the converted decl.  */
-  for (size_t i = 0; i < builtin_converted_decls.length (); ++i)
+  unsigned saved_builtin_decls_length = builtin_converted_decls.length ();
+  for (size_t i = 0; i < saved_builtin_decls_length; ++i)
     {
       tree t = builtin_converted_decls[i].ctype;
       if (TYPE_MAIN_VARIANT (t) == TYPE_MAIN_VARIANT (type))
@@ -249,6 +250,9 @@ build_frontend_type (tree type)
          Type *ftype = build_frontend_type (TREE_TYPE (field));
          if (!ftype)
            {
+             /* Drop any field types that got cached before the conversion
+                of this record type failed.  */
+             builtin_converted_decls.truncate (saved_builtin_decls_length);
              delete sdecl->members;
              return NULL;
            }
@@ -307,6 +311,9 @@ build_frontend_type (tree type)
              Type *targ = build_frontend_type (argtype);
              if (!targ)
                {
+                 /* Drop any parameter types that got cached before the
+                    conversion of this function type failed.  */
+                 builtin_converted_decls.truncate (saved_builtin_decls_length);
                  delete args;
                  return NULL;
                }
-- 
2.30.2