[llvm-commits] [llvm] r139972 - /llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.cpp

[Owen Anderson]

Author: resistor
Date: Fri Sep 16 18:30:01 2011
New Revision: 139972

URL: http://llvm.org/viewvc/llvm-project?rev=139972&view=rev
Log:
Bitfield mask instructions are unpredictable if the encoded LSB is higher than the encoded MSB.

Modified:
    llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.cpp

Modified: llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.cpp?rev=139972&r1=139971&r2=139972&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.cpp (original)
+++ llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.cpp Fri Sep 16 18:30:01 2011
@@ -1004,12 +1004,15 @@
   unsigned msb = fieldFromInstruction32(Val, 5, 5);
   unsigned lsb = fieldFromInstruction32(Val, 0, 5);
 
+  DecodeStatus S = MCDisassembler::Success;
+  if (lsb > msb) Check(S, MCDisassembler::SoftFail);
+
   uint32_t msb_mask = 0xFFFFFFFF;
   if (msb != 31) msb_mask = (1U << (msb+1)) - 1;
   uint32_t lsb_mask = (1U << lsb) - 1;
 
   Inst.addOperand(MCOperand::CreateImm(~(msb_mask ^ lsb_mask)));
-  return MCDisassembler::Success;
+  return S;
 }
 
 static DecodeStatus DecodeCopMemInstruction(llvm::MCInst &Inst, unsigned Insn,