Fix all debug directives.

The backtrace when a fortify check failed was not correct. This change
adds all of the necessary directives to get a correct backtrace.

Fix the strcmp directives and change all labels to local labels.

Testing:
- Verify that the runtime can decode the stack for __memcpy_chk, __memset_chk,
  __strcpy_chk, __strcat_chk fortify failures.
- Verify that gdb can decode the stack properly when hitting a fortify check.
- Verify that the runtime can decode the stack for a seg fault for all of the
  _chk functions and for memcpy/memset.
- Verify that gdb can decode the stack for a seg fault for all of the _chk
  functions and for memcpy/memset.
- Verify that the runtime can decode the stack for a seg fault for strcmp.
- Verify that gdb can decode the stack for a seg fault in strcmp.

Bug: 10342460
Bug: 10345269

Merge from internal master.

(cherry-picked from 05332f2ce7e542d32ff4d5cd9f60248ad71fbf0d)

Change-Id: Ibc919b117cfe72b9ae97e35bd48185477177c5ca
diff --git a/libc/arch-arm/krait/bionic/memcpy.S b/libc/arch-arm/krait/bionic/memcpy.S
index 3b4fca4..e433402 100644
--- a/libc/arch-arm/krait/bionic/memcpy.S
+++ b/libc/arch-arm/krait/bionic/memcpy.S
@@ -55,22 +55,23 @@
 ENTRY(memcpy)
         .cfi_startproc
         pld     [r1, #64]
-        .save   {r0, lr}
         stmfd   sp!, {r0, lr}
+        .save   {r0, lr}
         .cfi_def_cfa_offset 8
         .cfi_rel_offset r0, 0
         .cfi_rel_offset lr, 4
-
-        #include "memcpy_base.S"
         .cfi_endproc
 END(memcpy)
 
-        .fnstart
+#define MEMCPY_BASE         __memcpy_base
+#define MEMCPY_BASE_ALIGNED __memcpy_base_aligned
+#include "memcpy_base.S"
+
+ENTRY(__memcpy_chk_fail)
         .cfi_startproc
-__memcpy_chk_fail:
         // Preserve lr for backtrace.
-        .save   {lr}
         push    {lr}
+        .save   {lr}
         .cfi_def_cfa_offset 4
         .cfi_rel_offset lr, 0
 
@@ -84,7 +85,7 @@
 error_message:
         .word   error_string-(1b+4)
         .cfi_endproc
-        .fnend
+END(__memcpy_chk_fail)
 
         .data
 error_string: