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

[Iain Buclaw <ibuclaw@gdcproject.org>]

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