[PATCH] Set start_location to 0 if we ran out of line map space

[H.J. Lu]

With profiledbootstrap and --with-build-config=bootstrap-lto, linemap_add
may create a macro map when we run out of line map space.  This patch
changes start_location to UNKNOWN_LOCATION (0) in this case.

Tested with profiledbootstrap and --with-build-config=bootstrap-lto on
Linux/x86-64.

        PR bootstrap/86872
        * line-map.c (pure_location_p): Return true if linemap_lookup
        returns NULL.
        (linemap_add): Set start_location to 0 if we run out of line map
        space.
---
 libcpp/line-map.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/libcpp/line-map.c b/libcpp/line-map.c
index 555cd129a9c..cafe42273eb 100644
--- a/libcpp/line-map.c
+++ b/libcpp/line-map.c
@@ -304,6 +304,8 @@ pure_location_p (line_maps *set, source_location loc)
     return false;
 
   const line_map *map = linemap_lookup (set, loc);
+  if (map == NULL)
+    return true;
   const line_map_ordinary *ordmap = linemap_check_ordinary (map);
 
   if (loc & ((1U << ordmap->m_range_bits) - 1))
@@ -492,6 +494,11 @@ linemap_add (struct line_maps *set, enum lc_reason reason,
     }
 
   linemap_assert (reason != LC_ENTER_MACRO);
+
+  if (start_location >= LINE_MAP_MAX_LOCATION)
+    /* We ran out of line map space.   */
+    start_location = 0;
+
   line_map_ordinary *map
     = linemap_check_ordinary (new_linemap (set, start_location));
   map->reason = reason;
-- 
2.17.1