Optimize __memset_chk, __memcpy_chk.

This change creates assembler versions of __memcpy_chk/__memset_chk
that is implemented in the memcpy/memset assembler code. This change
avoids an extra call to memcpy/memset, instead allowing a simple fall
through to occur from the chk code into the body of the real
implementation.

Testing:

- Ran the libc_test on __memcpy_chk/__memset_chk on all nexus devices.
- Wrote a small test executable that has three calls to __memcpy_chk and
  three calls to __memset_chk. First call dest_len is length + 1. Second
  call dest_len is length. Third call dest_len is length - 1.
  Verified that the first two calls pass, and the third fails. Examined
  the logcat output on all nexus devices to verify that the fortify
  error message was sent properly.
- I benchmarked the new __memcpy_chk and __memset_chk on all systems. For
  __memcpy_chk and large copies, the savings is relatively small (about 1%).
  For small copies, the savings is large on cortex-a15/krait devices
  (between 5% to 30%).
  For cortex-a9 and small copies, the speed up is present, but relatively
  small (about 3% to 5%).
  For __memset_chk and large copies, the savings is also small (about 1%).
  However, all processors show larger speed-ups on small copies (about 30% to
  100%).

Bug: 9293744

Change-Id: I8926d59fe2673e36e8a27629e02a7b7059ebbc98

libc/private/libc_events.h

@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef _LIBC_EVENTS_H
+#define _LIBC_EVENTS_H
+
+
+// This is going to be included in assembler code so only allow #define
+// values instead of defining an enum.
+
+#define BIONIC_EVENT_MEMCPY_BUFFER_OVERFLOW   80100
+#define BIONIC_EVENT_STRCAT_BUFFER_OVERFLOW   80105
+#define BIONIC_EVENT_MEMMOVE_BUFFER_OVERFLOW  80110
+#define BIONIC_EVENT_STRNCAT_BUFFER_OVERFLOW  80115
+#define BIONIC_EVENT_STRNCPY_BUFFER_OVERFLOW  80120
+#define BIONIC_EVENT_MEMSET_BUFFER_OVERFLOW   80125
+#define BIONIC_EVENT_STRCPY_BUFFER_OVERFLOW   80130
+
+#define BIONIC_EVENT_RESOLVER_OLD_RESPONSE    80300
+#define BIONIC_EVENT_RESOLVER_WRONG_SERVER    80305
+#define BIONIC_EVENT_RESOLVER_WRONG_QUERY     80310
+
+#endif // _LIBC_EVENTS_H