The purpose of the patch is to fix the syntax of ARM mrc and mrc2 instructions when they are used to write to the APSR. In this case, the destination operand should be APSR_nzcv, and the encoding of the target should be 0b1111 (same as for PC). In pre-UAL syntax, this form used the PC register as a textual target. This is still allowed for backward compatibility.

llvm-svn: 181705

1 files changed, 18 insertions, 0 deletions

diff --git a/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp b/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
index ac937f35345..d2896377cc9 100644
--- a/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
+++ b/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
@@ -156,6 +156,9 @@ static DecodeStatus DecodeGPRRegisterClass(MCInst &Inst, unsigned RegNo,
 static DecodeStatus DecodeGPRnopcRegisterClass(MCInst &Inst,
                                                unsigned RegNo, uint64_t Address,
                                                const void *Decoder);
+static DecodeStatus DecodeGPRwithAPSRRegisterClass(MCInst &Inst,
+                                               unsigned RegNo, uint64_t Address,
+                                               const void *Decoder);
 static DecodeStatus DecodetGPRRegisterClass(MCInst &Inst, unsigned RegNo,
                                    uint64_t Address, const void *Decoder);
 static DecodeStatus DecodetcGPRRegisterClass(MCInst &Inst, unsigned RegNo,
@@ -920,6 +923,21 @@ DecodeGPRnopcRegisterClass(MCInst &Inst, unsigned RegNo,
   return S;
 }
 
+static DecodeStatus
+DecodeGPRwithAPSRRegisterClass(MCInst &Inst, unsigned RegNo,
+                               uint64_t Address, const void *Decoder) {
+  DecodeStatus S = MCDisassembler::Success;
+
+  if (RegNo == 15)
+  {
+    Inst.addOperand(MCOperand::CreateReg(ARM::APSR_NZCV));
+    return MCDisassembler::Success;
+  }
+
+  Check(S, DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder));
+  return S;
+}
+
 static DecodeStatus DecodetGPRRegisterClass(MCInst &Inst, unsigned RegNo,
                                    uint64_t Address, const void *Decoder) {
   if (RegNo > 7)