preprocessor: Deferred macro support

For deferred macros we also need a new field on the macro itself, so
that the module machinery can determine the macro was imported.  Also
the documentation for the hashnode's deferred field was incomplete.

	libcpp/
	* include/cpplib.h (struct cpp_macro): Add imported_p field.
	(struct cpp_hashnode): Tweak deferred field documentation.
	* macro.c (_cpp_new_macro): Clear new field.
	(cpp_get_deferred_macro, get_deferred_or_lazy_macro): Assert
	more.

1 files changed, 5 insertions, 4 deletions

diff --git a/libcpp/macro.c b/libcpp/macro.c
index 0575585..cdb1821 100644
--- a/libcpp/macro.c
+++ b/libcpp/macro.c
@@ -3708,6 +3708,7 @@ _cpp_new_macro (cpp_reader *pfile, cpp_macro_kind kind, void *placement)
   macro->used = !CPP_OPTION (pfile, warn_unused_macros);
   macro->count = 0;
   macro->fun_like = 0;
+  macro->imported_p = false;
   macro->extra_tokens = 0;
   /* To suppress some diagnostics.  */
   macro->syshdr = pfile->buffer && pfile->buffer->sysp != 0;
@@ -3791,6 +3792,8 @@ cpp_macro *
 cpp_get_deferred_macro (cpp_reader *pfile, cpp_hashnode *node,
 			location_t loc)
 {
+  gcc_checking_assert (node->type == NT_USER_MACRO);
+
   node->value.macro = pfile->cb.user_deferred_macro (pfile, loc, node);
 
   if (!node->value.macro)
@@ -3807,11 +3810,9 @@ get_deferred_or_lazy_macro (cpp_reader *pfile, cpp_hashnode *node,
   if (!macro)
     {
       macro = cpp_get_deferred_macro (pfile, node, loc);
-      if (!macro)
-	return NULL;
+      gcc_checking_assert (!macro || !macro->lazy);
     }
-
-  if (macro->lazy)
+  else if (macro->lazy)
     {
       pfile->cb.user_lazy_macro (pfile, macro, macro->lazy - 1);
       macro->lazy = 0;