Add a check in the ARM disassembler for NEON instructions that would

reference registers past the end of the NEON register file, and report them
as invalid instead of asserting when trying to print them.  PR7746.

llvm-svn: 109933

1 files changed, 9 insertions, 5 deletions

diff --git a/llvm/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp b/llvm/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp
index d04e79eeb75..e48accc7b7f 100644
--- a/llvm/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp
+++ b/llvm/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp
@@ -2248,9 +2248,10 @@ static bool DisassembleNLdSt0(MCInst &MI, unsigned Opcode, uint32_t insn,
 
   // We have homogeneous NEON registers for Load/Store.
   unsigned RegClass = 0;
+  bool DRegPair = UseDRegPair(Opcode);
 
   // Double-spaced registers have increments of 2.
-  unsigned Inc = DblSpaced ? 2 : 1;
+  unsigned Inc = (DblSpaced || DRegPair) ? 2 : 1;
 
   unsigned Rn = decodeRn(insn);
   unsigned Rm = decodeRm(insn);
@@ -2296,8 +2297,7 @@ static bool DisassembleNLdSt0(MCInst &MI, unsigned Opcode, uint32_t insn,
     RegClass = OpInfo[OpIdx].RegClass;
     while (OpIdx < NumOps && (unsigned)OpInfo[OpIdx].RegClass == RegClass) {
       MI.addOperand(MCOperand::CreateReg(
-                      getRegisterEnum(B, RegClass, Rd,
-                                      UseDRegPair(Opcode))));
+                      getRegisterEnum(B, RegClass, Rd, DRegPair)));
       Rd += Inc;
       ++OpIdx;
     }
@@ -2316,8 +2316,7 @@ static bool DisassembleNLdSt0(MCInst &MI, unsigned Opcode, uint32_t insn,
 
     while (OpIdx < NumOps && (unsigned)OpInfo[OpIdx].RegClass == RegClass) {
       MI.addOperand(MCOperand::CreateReg(
-                      getRegisterEnum(B, RegClass, Rd,
-                                      UseDRegPair(Opcode))));
+                      getRegisterEnum(B, RegClass, Rd, DRegPair)));
       Rd += Inc;
       ++OpIdx;
     }
@@ -2355,6 +2354,11 @@ static bool DisassembleNLdSt0(MCInst &MI, unsigned Opcode, uint32_t insn,
     }
   }
 
+  // Accessing registers past the end of the NEON register file is not
+  // defined.
+  if (Rd > 32)
+    return false;
+
   return true;
 }