[compiler-rt] r266371 - [sanitizer] [SystemZ] Fix stack traces.

[Marcin Koscielnicki via llvm-commits]

Author: koriakin
Date: Thu Apr 14 16:19:27 2016
New Revision: 266371

URL: http://llvm.org/viewvc/llvm-project?rev=266371&view=rev
Log:
[sanitizer] [SystemZ] Fix stack traces.

On s390, the return address is in %r14, which is saved 14 words from
the frame pointer.

Unfortunately, there's no way to do a proper fast backtrace on SystemZ
with current LLVM - the saved %r15 in fixed-layout register save
area points to the containing frame itself, and not to the next one.
Likewise for %r11 - it's identical to %r15, unless alloca is used
(and even if it is, it's still useless).  There's just no way to
determine frame size / next frame pointer.  -mbackchain would fix that
(and make the current code just work), but that's not yet supported
in LLVM.  We will thus need to XFAIL some asan tests
(Linux/stack-trace-dlclose.cc, deep_stack_uaf.cc).

Differential Revision: http://reviews.llvm.org/D18895

Modified:
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_stacktrace.cc

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_stacktrace.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_stacktrace.cc?rev=266371&r1=266370&r2=266371&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_stacktrace.cc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_stacktrace.cc Thu Apr 14 16:19:27 2016
@@ -92,6 +92,8 @@ void BufferedStackTrace::FastUnwindStack
         !IsAligned((uptr)caller_frame, sizeof(uhwptr)))
       break;
     uhwptr pc1 = caller_frame[2];
+#elif defined(__s390__)
+    uhwptr pc1 = frame[14];
 #else
     uhwptr pc1 = frame[1];
 #endif