Fix thinko in libcpp preparation patch for modules

The problem is that the new IS_MACRO_LOC macro:

inline bool
IS_MACRO_LOC (location_t loc)
{
  return !IS_ORDINARY_LOC (loc) && !IS_ADHOC_LOC (loc);
}

is not fully correct since the position of the macro lines is not fixed:

/* Returns the lowest location [of a token resulting from macro
   expansion] encoded in this line table.  */
inline location_t
LINEMAPS_MACRO_LOWEST_LOCATION (const line_maps *set)
{
  return LINEMAPS_MACRO_USED (set)
         ? MAP_START_LOCATION (LINEMAPS_LAST_MACRO_MAP (set))
         : MAX_LOCATION_T + 1;
}

In Ada, LINEMAPS_MACRO_USED is false so LINEMAPS_MACRO_LOWEST_LOCATION is
MAX_LOCATION_T + 1, but IS_MACRO_LOC nevertheless returns true for anything
in the range [LINE_MAP_MAX_LOCATION; MAX_LOCATION_T], thus yielding an ICE
in linemap_macro_map_lookup for very large files.

libcpp/
	* include/line-map.h (IS_MACRO_LOC): Delete.
	* line-map.c (linemap_location_from_macro_expansion_p): Test
	LINEMAPS_MACRO_LOWEST_LOCATION of the linemap.
gcc/cp/
	* module.cc (ordinary_loc_of): Test LINEMAPS_MACRO_LOWEST_LOCATION
	of the linemap.
	(module_state::write_location): Likewise.

1 files changed, 3 insertions, 7 deletions

diff --git a/libcpp/include/line-map.h b/libcpp/include/line-map.h
index 40919d0..7d96417 100644
--- a/libcpp/include/line-map.h
+++ b/libcpp/include/line-map.h
@@ -563,7 +563,7 @@ struct GTY((tag ("2"))) line_map_macro : public line_map {
 #define linemap_assert_fails(EXPR) (! (EXPR))
 #endif
 
-/* Get whether location LOC is an ad-hoc, ordinary or macro location.  */
+/* Get whether location LOC is an ordinary location.  */
 
 inline bool
 IS_ORDINARY_LOC (location_t loc)
@@ -571,18 +571,14 @@ IS_ORDINARY_LOC (location_t loc)
   return loc < LINE_MAP_MAX_LOCATION;
 }
 
+/* Get whether location LOC is an ad-hoc location.  */
+
 inline bool
 IS_ADHOC_LOC (location_t loc)
 {
   return loc > MAX_LOCATION_T;
 }
 
-inline bool
-IS_MACRO_LOC (location_t loc)
-{
-  return !IS_ORDINARY_LOC (loc) && !IS_ADHOC_LOC (loc);
-}
-
 /* Categorize line map kinds.  */
 
 inline bool