From: Andreas Arnez <arnez at linux dot vnet dot ibm dot com>
Date: Wed, 13 Nov 2013 13:00:44 +0000 (+0100)
Subject: Fix GDB crash with upstream GCC due to memcpy(NULL, ...)
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=19a1b230f33dbcfa54cd1a9f88c2d5158f833f6f;p=deliverable%2Fbinutils-gdb.git

Fix GDB crash with upstream GCC due to memcpy(NULL, ...)

Similar to qsort(), the glibc version of memcpy() also declares its
arguments with __attribute__(__nonnull__(...)).  If NULL is passed
anyway, upstream GCC's new pass '-fisolate-erroneous-paths' typically
causes a trap in such cases.  I've encountered this with GDB in
chain_candidate() when trying to execute the break.exp test case.

gdb/
2013-11-13  Andreas Arnez  <arnez@linux.vnet.ibm.com>

	* dwarf2loc.c (chain_candidate): Prevent invoking memcpy with
	NULL.
---

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 630f86b8e7..fec7528390 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2013-11-15  Andreas Arnez  <arnez@linux.vnet.ibm.com>
+
+	* dwarf2loc.c (chain_candidate): Prevent invoking memcpy with
+	NULL.
+
 2013-11-15  Tom Tromey  <tromey@redhat.com>
 
 	PR c++/16117:
diff --git a/gdb/dwarf2loc.c b/gdb/dwarf2loc.c
index 8b6eb663b6..2879ead5e7 100644
--- a/gdb/dwarf2loc.c
+++ b/gdb/dwarf2loc.c
@@ -761,8 +761,9 @@ chain_candidate (struct gdbarch *gdbarch, struct call_site_chain **resultp,
 					   * (length - 1));
       result->length = length;
       result->callers = result->callees = length;
-      memcpy (result->call_site, VEC_address (call_sitep, chain),
-	      sizeof (*result->call_site) * length);
+      if (!VEC_empty (call_sitep, chain))
+	memcpy (result->call_site, VEC_address (call_sitep, chain),
+		sizeof (*result->call_site) * length);
       *resultp = result;
 
       if (entry_values_debug)