Auto-sandboxing: Switch to automatic scratch register invalidation

lib/Target/ARM/MCTargetDesc/ARMMCNaClExpander.cpp

Index: lib/Target/ARM/MCTargetDesc/ARMMCNaClExpander.cpp
diff --git a/lib/Target/ARM/MCTargetDesc/ARMMCNaClExpander.cpp b/lib/Target/ARM/MCTargetDesc/ARMMCNaClExpander.cpp
index 41182314f8e5ac39fd5cffeb5ccc3ab53c9f68da..a656049c6c683b1d63eeee5e1d4fa064d26a4a35 100644
--- a/lib/Target/ARM/MCTargetDesc/ARMMCNaClExpander.cpp
+++ b/lib/Target/ARM/MCTargetDesc/ARMMCNaClExpander.cpp
@@ -28,6 +28,10 @@ using namespace llvm;
 const unsigned kBranchTargetMask = 0xC000000F;
 const unsigned kAlwaysPredicate = 14;
 
+bool ARM::ARMMCNaClExpander::isValidScratchRegister(unsigned Reg) const {
+  return true;
+}
+

[dominickd, 2015/08/06 17:45:20]

Shouldn't PC or SP return false?

[Derek Schuff, 2015/08/06 20:46:01]

Yes. I had a // TODO(dschuff): implement
there because I didn't have any tests and I started this before you had any
actual ARM logic checked in. I'll go ahead and put that in now though.

 static void emitBicMask(unsigned Mask, unsigned Reg, int64_t Pred,
                         MCStreamer &Out, const MCSubtargetInfo &STI) {
   MCInst Bic;