PR c++/87721 reports a crash in get_substring_ranges_for_loc introduced
by r265271, my fix for PR 87562.
The new issue occurs when attempting to get a location with a string
literal inside a macro in which the first token is __FILE__ (formed via
concatenation). Attempting to get the spelling location of __FILE__
fails, leading to NULL for start_ord_map and final_ord_map, and thus
a NULL pointer dereference.
Given that our "on-demand" substring locations approach reparses the
string literals, there isn't a good way to access the locations inside
such string literals: attempting to reparse __FILE__ fails with a
"missing open quote".
This patch applies the easy fix by gracefully rejecting the case where
the spelling locations for the start or finish give us NULL maps.
gcc/ChangeLog:
PR c++/87721
* input.c (get_substring_ranges_for_loc): Detect if
linemap_resolve_location gives us a NULL map, and reject
this case.
gcc/testsuite/ChangeLog:
PR c++/87721
* c-c++-common/substring-location-PR-87721.c: New test.
* gcc.dg/plugin/diagnostic-test-string-literals-1.c: Add test for
PR 87721.
* gcc.dg/plugin/diagnostic_plugin_test_string_literals.c
(test_string_literals): Fold the index arguments before checking
for INTEGER_CST.
From-SVN: r265611
