[PATCH] [MSan] [MIPS] Adding support for MIPS64

[Kostya Serebryany]

================
Comment at: lib/msan/msan.cc:510
@@ -509,2 +509,3 @@
 
 static void* get_tls_base() {
+  // as this function is only relevant for architecture supporting msandr
----------------
This code will get deleted with http://reviews.llvm.org/D6268, please wait for it. 

================
Comment at: lib/msan/msan_report.cc:58
@@ +57,3 @@
+      pc += 1;
+    #elif defined(__mips64)
+      pc += 8;
----------------
I'd prefer not to have #ifdef here. 
At the very least, move it into a separate function near the StackTrace::GetPreviousInstructionPc
but I would like to understand why we need this adjustment here at all.

http://reviews.llvm.org/D5906