[ARM] Allow SP in rGPR, starting from ARMv8

Summary:
This patch handles assembly and disassembly, but not codegen, as of yet.

Additionally, it fixes a bug whereby SP and PC as shifted-reg operands
were treated as predictable in ARMv7 Thumb; and it enables the tests
for invalid and unpredictable instructions to run on both ARMv7 and ARMv8.

Reviewers: jmolloy, rengolin

Subscribers: aemerson, rengolin, llvm-commits

Differential Revision: http://reviews.llvm.org/D14141

llvm-svn: 251516

2 files changed, 36 insertions, 13 deletions

diff --git a/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp b/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
index b0bde037b91..5a82cf36bda 100644
--- a/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ b/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -343,6 +343,7 @@ public:
     Match_RequiresNotITBlock,
     Match_RequiresV6,
     Match_RequiresThumb2,
+    Match_RequiresV8,
 #define GET_OPERAND_DIAGNOSTIC_TYPES
 #include "ARMGenAsmMatcher.inc"
 
@@ -8529,18 +8530,29 @@ unsigned ARMAsmParser::checkTargetMatchPredicate(MCInst &Inst) {
     if (isThumbTwo() && Inst.getOperand(OpNo).getReg() == ARM::CPSR &&
         inITBlock())
       return Match_RequiresNotITBlock;
+  } else if (isThumbOne()) {
+    // Some high-register supporting Thumb1 encodings only allow both registers
+    // to be from r0-r7 when in Thumb2.
+    if (Opc == ARM::tADDhirr && !hasV6MOps() &&
+        isARMLowRegister(Inst.getOperand(1).getReg()) &&
+        isARMLowRegister(Inst.getOperand(2).getReg()))
+      return Match_RequiresThumb2;
+    // Others only require ARMv6 or later.
+    else if (Opc == ARM::tMOVr && !hasV6Ops() &&
+             isARMLowRegister(Inst.getOperand(0).getReg()) &&
+             isARMLowRegister(Inst.getOperand(1).getReg()))
+      return Match_RequiresV6;
   }
-  // Some high-register supporting Thumb1 encodings only allow both registers
-  // to be from r0-r7 when in Thumb2.
-  else if (Opc == ARM::tADDhirr && isThumbOne() && !hasV6MOps() &&
-           isARMLowRegister(Inst.getOperand(1).getReg()) &&
-           isARMLowRegister(Inst.getOperand(2).getReg()))
-    return Match_RequiresThumb2;
-  // Others only require ARMv6 or later.
-  else if (Opc == ARM::tMOVr && isThumbOne() && !hasV6Ops() &&
-           isARMLowRegister(Inst.getOperand(0).getReg()) &&
-           isARMLowRegister(Inst.getOperand(1).getReg()))
-    return Match_RequiresV6;
+
+  for (unsigned I = 0; I < MCID.NumOperands; ++I)
+    if (MCID.OpInfo[I].RegClass == ARM::rGPRRegClassID) {
+      // rGPRRegClass excludes PC, and also excluded SP before ARMv8
+      if ((Inst.getOperand(I).getReg() == ARM::SP) && !hasV8Ops())
+        return Match_RequiresV8;
+      else if (Inst.getOperand(I).getReg() == ARM::PC)
+        return Match_InvalidOperand;
+    }
+
   return Match_Success;
 }
 
@@ -8639,6 +8651,8 @@ bool ARMAsmParser::MatchAndEmitInstruction(SMLoc IDLoc, unsigned &Opcode,
     return Error(IDLoc, "instruction variant requires ARMv6 or later");
   case Match_RequiresThumb2:
     return Error(IDLoc, "instruction variant requires Thumb2");
+  case Match_RequiresV8:
+    return Error(IDLoc, "instruction variant requires ARMv8 or later");
   case Match_ImmRange0_15: {
     SMLoc ErrorLoc = ((ARMOperand &)*Operands[ErrorInfo]).getStartLoc();
     if (ErrorLoc == SMLoc()) ErrorLoc = IDLoc;
@@ -9996,6 +10010,10 @@ unsigned ARMAsmParser::validateTargetOperandClass(MCParsedAsmOperand &AsmOp,
              "expression value must be representable in 32 bits");
     }
     break;
+  case MCK_rGPR:
+    if (hasV8Ops() && Op.isReg() && Op.getReg() == ARM::SP)
+      return Match_Success;
+    break;
   case MCK_GPRPair:
     if (Op.isReg() &&
         MRI->getRegClass(ARM::GPRRegClassID).contains(Op.getReg()))
diff --git a/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp b/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
index 38cb585edc0..04e4245b633 100644
--- a/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
+++ b/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
@@ -966,8 +966,13 @@ static DecodeStatus DecodetcGPRRegisterClass(MCInst &Inst, unsigned RegNo,
 static DecodeStatus DecoderGPRRegisterClass(MCInst &Inst, unsigned RegNo,
                                    uint64_t Address, const void *Decoder) {
   DecodeStatus S = MCDisassembler::Success;
-  if (RegNo == 13 || RegNo == 15)
+
+  const FeatureBitset &featureBits =
+    ((const MCDisassembler*)Decoder)->getSubtargetInfo().getFeatureBits();
+
+  if ((RegNo == 13 && !featureBits[ARM::HasV8Ops]) || RegNo == 15)
     S = MCDisassembler::SoftFail;
+
   Check(S, DecodeGPRRegisterClass(Inst, RegNo, Address, Decoder));
   return S;
 }
@@ -1127,7 +1132,7 @@ static DecodeStatus DecodeSORegImmOperand(MCInst &Inst, unsigned Val,
   unsigned imm = fieldFromInstruction(Val, 7, 5);
 
   // Register-immediate
-  if (!Check(S, DecodeGPRRegisterClass(Inst, Rm, Address, Decoder)))
+  if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
     return MCDisassembler::Fail;
 
   ARM_AM::ShiftOpc Shift = ARM_AM::lsl;