[libunwind] r366587 - [libunwind][ARM] Fix loading FP registers on big-endian targets

[Mikhail Maltsev via cfe-commits]

Author: miyuki
Date: Fri Jul 19 08:20:32 2019
New Revision: 366587

URL: http://llvm.org/viewvc/llvm-project?rev=366587&view=rev
Log:
[libunwind][ARM] Fix loading FP registers on big-endian targets

Summary:
The function Unwind-EHABI.cpp:_Unwind_VRS_Pop loads the saved values of
64-bit FP registers as two 32-bit words because they might not be
8-byte aligned. Combining these words into a 64-bit value has to be
done differently on big-endian platforms.

Reviewers: ostannard, john.brawn, dmgreen

Reviewed By: ostannard

Subscribers: kristof.beyls, christof, libcxx-commits

Tags: #libc

Differential Revision: https://reviews.llvm.org/D64996

Modified:
    libunwind/trunk/src/Unwind-EHABI.cpp

Modified: libunwind/trunk/src/Unwind-EHABI.cpp
URL: http://llvm.org/viewvc/llvm-project/libunwind/trunk/src/Unwind-EHABI.cpp?rev=366587&r1=366586&r2=366587&view=diff
==============================================================================
--- libunwind/trunk/src/Unwind-EHABI.cpp (original)
+++ libunwind/trunk/src/Unwind-EHABI.cpp Fri Jul 19 08:20:32 2019
@@ -941,8 +941,13 @@ _Unwind_VRS_Pop(_Unwind_Context *context
       // format 1", which is equivalent to FSTMD + a padding word.
       for (uint32_t i = first; i < end; ++i) {
         // SP is only 32-bit aligned so don't copy 64-bit at a time.
-        uint64_t value = *sp++;
-        value |= ((uint64_t)(*sp++)) << 32;
+        uint32_t w0 = *sp++;
+        uint32_t w1 = *sp++;
+#ifdef __LITTLE_ENDIAN__
+        uint64_t value = (w1 << 32) | w0;
+#else
+        uint64_t value = (w0 << 32) | w1;
+#endif
         if (_Unwind_VRS_Set(context, regclass, i, representation, &value) !=
             _UVRSR_OK)
           return _UVRSR_FAILED;