From: Kevin Buettner <kevinb@redhat.com>
Date: Wed, 30 Sep 2015 12:54:15 +0000 (-0700)
Subject: infcmd.c: Don't attempt to record a NULL value after a finish command.
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=aca20ec47359776488863193660cf9fd2fe3cfe7;p=binutils-gdb.git

infcmd.c: Don't attempt to record a NULL value after a finish command.

Architectures which use RETURN_VALUE_STRUCT_CONVENTION will have a
NULL return value after executing a finish command.  See get_return_value()
in infcmd.c.

This patch avoids an eventual SIGSEV (caused by attempting to
derefrence a NULL pointer) by adding a suitable test to
finish_command_fsm_should_stop().

I encountered this problem while testing msp430:

(gdb) PASS: gdb.base/structs.exp: zed L<n> for finish; return 1 structs-tc
finish
Run till exit from #0  fun1 () at /ironwood1/sourceware-git/msp430-elf/../binutils-gdb/gdb/testsuite/gdb.base/structs.c:125
ERROR: Process no longer exists

gdb/ChangeLog:
    	* infcmd.c (finish_command_fsm_should_stop): Don't attempt to
    	record a NULL value.
---

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 667bf27fe12..b6355e799b5 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2015-09-29  Kevin Buettner  <kevinb@redhat.com>
+
+	* infcmd.c (finish_command_fsm_should_stop): Don't attempt to
+	record a NULL value.
+
 2015-09-29  Kevin Buettner  <kevinb@redhat.com>
 
 	* msp430-tdep.c (msp430_push_dummy_call): Treat reference, struct,
diff --git a/gdb/infcmd.c b/gdb/infcmd.c
index c4d7d8b5d6d..54aa1ef4cc4 100644
--- a/gdb/infcmd.c
+++ b/gdb/infcmd.c
@@ -1794,7 +1794,8 @@ finish_command_fsm_should_stop (struct thread_fsm *self)
 
 	  func = read_var_value (f->function, NULL, get_current_frame ());
 	  rv->value = get_return_value (func, rv->type);
-	  rv->value_history_index = record_latest_value (rv->value);
+	  if (rv->value != NULL)
+	    rv->value_history_index = record_latest_value (rv->value);
 	}
     }
   else if (tp->control.stop_step)