[libcxxabi] r229207 - Address post-commit review comments

[Jonathan Roelofs]

Author: jroelofs
Date: Fri Feb 13 19:38:35 2015
New Revision: 229207

URL: http://llvm.org/viewvc/llvm-project?rev=229207&view=rev
Log:
Address post-commit review comments

Modified:
    libcxxabi/trunk/src/Unwind/UnwindRegistersSave.S

Modified: libcxxabi/trunk/src/Unwind/UnwindRegistersSave.S
URL: http://llvm.org/viewvc/llvm-project/libcxxabi/trunk/src/Unwind/UnwindRegistersSave.S?rev=229207&r1=229206&r2=229207&view=diff
==============================================================================
--- libcxxabi/trunk/src/Unwind/UnwindRegistersSave.S (original)
+++ libcxxabi/trunk/src/Unwind/UnwindRegistersSave.S Fri Feb 13 19:38:35 2015
@@ -317,6 +317,9 @@ DEFINE_LIBUNWIND_FUNCTION(unw_getcontext
   str lr, [r0, #60]  @ store return address as pc
 #endif
 #if __ARM_ARCH_ISA_THUMB1 == 1
+  @ T1 does not have a non-cpsr-clobbering register-zeroing instruction.
+  @ It is safe to use here though because we are about to return, and cpsr is
+  @ not expected to be preserved.
   movs r0, #0        @ return UNW_ESUCCESS
 #else
   mov r0, #0         @ return UNW_ESUCCESS