[ARM] Fix endianness of Thumb .inst.w directive

Wide Thumb2 instructions should be emitted into the object file as pairs of
16-bit words of the appropriate endianness, not one 32-bit word.

Differential revision: https://reviews.llvm.org/D41185

llvm-svn: 321799

1 files changed, 4 insertions, 2 deletions

diff --git a/llvm/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp b/llvm/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp
index d465da1a7bb..9d73c7629da 100644
--- a/llvm/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp
+++ b/llvm/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp
@@ -512,9 +512,11 @@ public:
 
       assert(IsThumb);
       EmitThumbMappingSymbol();
+      // Thumb wide instructions are emitted as a pair of 16-bit words of the
+      // appropriate endianness.
       for (unsigned II = 0, IE = Size; II != IE; II = II + 2) {
-        const unsigned I0 = LittleEndian ? II + 0 : (Size - II - 1);
-        const unsigned I1 = LittleEndian ? II + 1 : (Size - II - 2);
+        const unsigned I0 = LittleEndian ? II + 0 : II + 1;
+        const unsigned I1 = LittleEndian ? II + 1 : II + 0;
         Buffer[Size - II - 2] = uint8_t(Inst >> I0 * CHAR_BIT);
         Buffer[Size - II - 1] = uint8_t(Inst >> I1 * CHAR_BIT);
       }