[SelectionDAG] Verify SDTCisVT and SDTCVecEltisVT constraints (llvm#150125)

Teach `SDNodeInfoEmitter` TableGen backend to process `SDTypeConstraint`
records and emit tables for them. The tables are used by
`SDNodeInfo::verifyNode()` to validate a node being created.

This PR only adds validation code for `SDTCisVT` and `SDTCVecEltisVT`
constraints to keep it smaller.

Pull Request: llvm#150125

Author: s-barannikov

llvm/include/llvm/CodeGen/SDNodeInfo.h

@@ -48,11 +48,21 @@ enum SDNF {
   SDNFIsStrictFP,
 };
 
+struct VTByHwModePair {
+  uint8_t Mode;
+  MVT::SimpleValueType VT;
+};
+
 struct SDTypeConstraint {
   SDTC Kind;
-  uint8_t OpNo;
-  uint8_t OtherOpNo;
-  MVT::SimpleValueType VT;
+  uint8_t ConstrainedValIdx;
+  uint8_t ConstrainingValIdx;
+  /// For Kind == SDTCisVT or SDTCVecEltisVT:
+  /// - if not using HwMode, NumHwModes == 0 and VT is MVT::SimpleValueType;
+  /// - otherwise, VT is offset into VTByHwModeTable and NumHwModes specifies
+  ///   the number of entries.
+  uint8_t NumHwModes;
+  uint16_t VT;
 };
 
 using SDNodeTSFlags = uint32_t;
@@ -76,13 +86,15 @@ class SDNodeInfo final {
   unsigned NumOpcodes;
   const SDNodeDesc *Descs;
   StringTable Names;
+  const VTByHwModePair *VTByHwModeTable;
   const SDTypeConstraint *Constraints;
 
 public:
   constexpr SDNodeInfo(unsigned NumOpcodes, const SDNodeDesc *Descs,
-                       StringTable Names, const SDTypeConstraint *Constraints)
+                       StringTable Names, const VTByHwModePair *VTByHwModeTable,
+                       const SDTypeConstraint *Constraints)
       : NumOpcodes(NumOpcodes), Descs(Descs), Names(Names),
-        Constraints(Constraints) {}
+        VTByHwModeTable(VTByHwModeTable), Constraints(Constraints) {}
 
   /// Returns true if there is a generated description for a node with the given
   /// target-specific opcode.

llvm/lib/CodeGen/SelectionDAG/SDNodeInfo.cpp

@@ -7,7 +7,10 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/CodeGen/SDNodeInfo.h"
+#include "llvm/CodeGen/SelectionDAG.h"
 #include "llvm/CodeGen/SelectionDAGNodes.h"
+#include "llvm/CodeGen/TargetLowering.h"
+#include "llvm/CodeGen/TargetSubtargetInfo.h"
 
 using namespace llvm;
 
@@ -40,6 +43,32 @@ static void checkOperandType(const SelectionDAG &DAG, const SDNode *N,
             ExpectedVT.getEVTString() + ", got " + ActualVT.getEVTString());
 }
 
+namespace {
+
+/// Similar to SDValue, but also records whether it is a result or an operand
+/// of a node so we can provide more precise diagnostics.
+class SDNodeValue {
+  const SDNode *N;
+  unsigned Idx;
+  bool IsRes;
+
+public:
+  SDNodeValue(const SDNode *N, unsigned Idx, bool IsRes)
+      : N(N), Idx(Idx), IsRes(IsRes) {}
+
+  SDValue getValue() const {
+    return IsRes ? SDValue(const_cast<SDNode *>(N), Idx) : N->getOperand(Idx);
+  }
+
+  EVT getValueType() const { return getValue().getValueType(); }
+
+  friend raw_ostream &operator<<(raw_ostream &OS, const SDNodeValue &Op) {
+    return OS << (Op.IsRes ? "result" : "operand") << " #" << Op.Idx;
+  }
+};
+
+} // namespace
+
 void SDNodeInfo::verifyNode(const SelectionDAG &DAG, const SDNode *N) const {
   const SDNodeDesc &Desc = getDesc(N->getOpcode());
   bool HasChain = Desc.hasProperty(SDNPHasChain);
@@ -125,4 +154,91 @@ void SDNodeInfo::verifyNode(const SelectionDAG &DAG, const SDNode *N) const {
                             " must be Register or RegisterMask");
     }
   }
+
+  unsigned VTHwMode =
+      DAG.getSubtarget().getHwMode(MCSubtargetInfo::HwMode_ValueType);
+
+  // Returns a constrained or constraining value (result or operand) of a node.
+  // ValIdx is the index of a node's value, as defined by SDTypeConstraint;
+  // that is, it indexes a node's operands after its results and ignores
+  // chain/glue values.
+  auto GetConstraintValue = [&](unsigned ValIdx) {
+    if (ValIdx < Desc.NumResults)
+      return SDNodeValue(N, ValIdx, /*IsRes=*/true);
+    return SDNodeValue(N, HasChain + (ValIdx - Desc.NumResults),
+                       /*IsRes=*/false);
+  };
+
+  auto GetConstraintVT = [&](const SDTypeConstraint &C) {
+    if (!C.NumHwModes)
+      return static_cast<MVT::SimpleValueType>(C.VT);
+    for (auto [Mode, VT] : ArrayRef(&VTByHwModeTable[C.VT], C.NumHwModes))
+      if (Mode == VTHwMode)
+        return VT;
+    llvm_unreachable("No value type for this HW mode");
+  };
+
+  SmallString<128> ES;
+  raw_svector_ostream SS(ES);
+
+  for (const SDTypeConstraint &C : getConstraints(N->getOpcode())) {
+    SDNodeValue Val = GetConstraintValue(C.ConstrainedValIdx);
+    EVT VT = Val.getValueType();
+
+    switch (C.Kind) {
+    case SDTCisVT: {
+      EVT ExpectedVT = GetConstraintVT(C);
+
+      bool IsPtr = ExpectedVT == MVT::iPTR;
+      if (IsPtr)
+        ExpectedVT =
+            DAG.getTargetLoweringInfo().getPointerTy(DAG.getDataLayout());
+
+      if (VT != ExpectedVT) {
+        SS << Val << " must have type " << ExpectedVT;
+        if (IsPtr)
+          SS << " (iPTR)";
+        SS << ", but has type " << VT;
+        reportNodeError(DAG, N, SS.str());
+      }
+      break;
+    }
+    case SDTCisPtrTy:
+      break;
+    case SDTCisInt:
+      break;
+    case SDTCisFP:
+      break;
+    case SDTCisVec:
+      break;
+    case SDTCisSameAs:
+      break;
+    case SDTCisVTSmallerThanOp:
+      break;
+    case SDTCisOpSmallerThanOp:
+      break;
+    case SDTCisEltOfVec:
+      break;
+    case SDTCisSubVecOfVec:
+      break;
+    case SDTCVecEltisVT: {
+      EVT ExpectedVT = GetConstraintVT(C);
+
+      if (!VT.isVector()) {
+        SS << Val << " must have vector type";
+        reportNodeError(DAG, N, SS.str());
+      }
+      if (VT.getVectorElementType() != ExpectedVT) {
+        SS << Val << " must have " << ExpectedVT << " element type, but has "
+           << VT.getVectorElementType() << " element type";
+        reportNodeError(DAG, N, SS.str());
+      }
+      break;
+    }
+    case SDTCisSameNumEltsAs:
+      break;
+    case SDTCisSameSizeAs:
+      break;
+    }
+  }
 }

llvm/lib/Target/AArch64/AArch64InstrInfo.td

@@ -1184,7 +1184,7 @@ def AArch64msrr : SDNode<"AArch64ISD::MSRR",
                                                SDTCisVT<2, i64>]>,
                           [SDNPHasChain]>;
 
-def SD_AArch64rshrnb : SDTypeProfile<1, 2, [SDTCisVec<0>, SDTCisVec<1>, SDTCisInt<2>]>;
+def SD_AArch64rshrnb : SDTypeProfile<1, 2, [SDTCisVec<0>, SDTCisVec<1>, SDTCisVT<2, i32>]>;
 // Vector narrowing shift by immediate (bottom)
 def AArch64rshrnb : SDNode<"AArch64ISD::RSHRNB_I", SD_AArch64rshrnb>;
 def AArch64rshrnb_pf : PatFrags<(ops node:$rs, node:$i),

llvm/lib/Target/AArch64/AArch64SelectionDAGInfo.cpp

@@ -32,35 +32,21 @@ AArch64SelectionDAGInfo::AArch64SelectionDAGInfo()
 
 void AArch64SelectionDAGInfo::verifyTargetNode(const SelectionDAG &DAG,
                                                const SDNode *N) const {
+  switch (N->getOpcode()) {
+  case AArch64ISD::WrapperLarge:
+    // operand #0 must have type i32, but has type i64
+    return;
+  }
+
   SelectionDAGGenTargetInfo::verifyTargetNode(DAG, N);
 
 #ifndef NDEBUG
   // Some additional checks not yet implemented by verifyTargetNode.
-  constexpr MVT FlagsVT = MVT::i32;
   switch (N->getOpcode()) {
-  case AArch64ISD::SUBS:
-    assert(N->getValueType(1) == FlagsVT);
-    break;
-  case AArch64ISD::ADC:
-  case AArch64ISD::SBC:
-    assert(N->getOperand(2).getValueType() == FlagsVT);
-    break;
-  case AArch64ISD::ADCS:
-  case AArch64ISD::SBCS:
-    assert(N->getValueType(1) == FlagsVT);
-    assert(N->getOperand(2).getValueType() == FlagsVT);
-    break;
-  case AArch64ISD::CSEL:
-  case AArch64ISD::CSINC:
-  case AArch64ISD::BRCOND:
-    assert(N->getOperand(3).getValueType() == FlagsVT);
-    break;
   case AArch64ISD::SADDWT:
   case AArch64ISD::SADDWB:
   case AArch64ISD::UADDWT:
   case AArch64ISD::UADDWB: {
-    assert(N->getNumValues() == 1 && "Expected one result!");
-    assert(N->getNumOperands() == 2 && "Expected two operands!");
     EVT VT = N->getValueType(0);
     EVT Op0VT = N->getOperand(0).getValueType();
     EVT Op1VT = N->getOperand(1).getValueType();
@@ -80,8 +66,6 @@ void AArch64SelectionDAGInfo::verifyTargetNode(const SelectionDAG &DAG,
   case AArch64ISD::SUNPKHI:
   case AArch64ISD::UUNPKLO:
   case AArch64ISD::UUNPKHI: {
-    assert(N->getNumValues() == 1 && "Expected one result!");
-    assert(N->getNumOperands() == 1 && "Expected one operand!");
     EVT VT = N->getValueType(0);
     EVT OpVT = N->getOperand(0).getValueType();
     assert(OpVT.isVector() && VT.isVector() && OpVT.isInteger() &&
@@ -98,8 +82,6 @@ void AArch64SelectionDAGInfo::verifyTargetNode(const SelectionDAG &DAG,
   case AArch64ISD::UZP2:
   case AArch64ISD::ZIP1:
   case AArch64ISD::ZIP2: {
-    assert(N->getNumValues() == 1 && "Expected one result!");
-    assert(N->getNumOperands() == 2 && "Expected two operands!");
     EVT VT = N->getValueType(0);
     EVT Op0VT = N->getOperand(0).getValueType();
     EVT Op1VT = N->getOperand(1).getValueType();
@@ -109,11 +91,8 @@ void AArch64SelectionDAGInfo::verifyTargetNode(const SelectionDAG &DAG,
     break;
   }
   case AArch64ISD::RSHRNB_I: {
-    assert(N->getNumValues() == 1 && "Expected one result!");
-    assert(N->getNumOperands() == 2 && "Expected two operands!");
     EVT VT = N->getValueType(0);
     EVT Op0VT = N->getOperand(0).getValueType();
-    EVT Op1VT = N->getOperand(1).getValueType();
     assert(VT.isVector() && VT.isInteger() &&
            "Expected integer vector result type!");
     assert(Op0VT.isVector() && Op0VT.isInteger() &&
@@ -122,8 +101,8 @@ void AArch64SelectionDAGInfo::verifyTargetNode(const SelectionDAG &DAG,
            "Expected vectors of equal size!");
     assert(VT.getVectorElementCount() == Op0VT.getVectorElementCount() * 2 &&
            "Expected input vector with half the lanes of its result!");
-    assert(Op1VT == MVT::i32 && isa<ConstantSDNode>(N->getOperand(1)) &&
-           "Expected second operand to be a constant i32!");
+    assert(isa<ConstantSDNode>(N->getOperand(1)) &&
+           "Expected second operand to be a constant!");
     break;
   }
   }

llvm/lib/Target/M68k/M68kISelLowering.cpp

@@ -1664,7 +1664,7 @@ static SDValue getBitTestCondition(SDValue Src, SDValue BitNo, ISD::CondCode CC,
   if (Src.getValueType() != BitNo.getValueType())
     BitNo = DAG.getNode(ISD::ANY_EXTEND, DL, Src.getValueType(), BitNo);
 
-  SDValue BTST = DAG.getNode(M68kISD::BTST, DL, MVT::i32, Src, BitNo);
+  SDValue BTST = DAG.getNode(M68kISD::BTST, DL, MVT::i8, Src, BitNo);
 
   // NOTE BTST sets CCR.Z flag if bit is 0, same as AND with bitmask
   M68k::CondCode Cond = CC == ISD::SETEQ ? M68k::COND_EQ : M68k::COND_NE;

llvm/lib/Target/M68k/M68kSelectionDAGInfo.cpp

@@ -16,4 +16,19 @@ using namespace llvm;
 M68kSelectionDAGInfo::M68kSelectionDAGInfo()
     : SelectionDAGGenTargetInfo(M68kGenSDNodeInfo) {}
 
+void M68kSelectionDAGInfo::verifyTargetNode(const SelectionDAG &DAG,
+                                            const SDNode *N) const {
+  switch (N->getOpcode()) {
+  case M68kISD::ADD:
+  case M68kISD::SUBX:
+    // result #1 must have type i8, but has type i32
+    return;
+  case M68kISD::SETCC:
+    // operand #1 must have type i8, but has type i32
+    return;
+  }
+
+  SelectionDAGGenTargetInfo::verifyTargetNode(DAG, N);
+}
+
 M68kSelectionDAGInfo::~M68kSelectionDAGInfo() = default;

llvm/lib/Target/M68k/M68kSelectionDAGInfo.h

@@ -21,6 +21,9 @@ class M68kSelectionDAGInfo : public SelectionDAGGenTargetInfo {
   M68kSelectionDAGInfo();
 
   ~M68kSelectionDAGInfo() override;
+
+  void verifyTargetNode(const SelectionDAG &DAG,
+                        const SDNode *N) const override;
 };
 
 } // namespace llvm

llvm/lib/Target/RISCV/RISCVSelectionDAGInfo.cpp

@@ -22,27 +22,22 @@ RISCVSelectionDAGInfo::~RISCVSelectionDAGInfo() = default;
 
 void RISCVSelectionDAGInfo::verifyTargetNode(const SelectionDAG &DAG,
                                              const SDNode *N) const {
+  SelectionDAGGenTargetInfo::verifyTargetNode(DAG, N);
+
 #ifndef NDEBUG
+  // Some additional checks not yet implemented by verifyTargetNode.
   switch (N->getOpcode()) {
-  default:
-    return SelectionDAGGenTargetInfo::verifyTargetNode(DAG, N);
   case RISCVISD::TUPLE_EXTRACT:
-    assert(N->getNumOperands() == 2 && "Expected three operands!");
     assert(N->getOperand(1).getOpcode() == ISD::TargetConstant &&
-           N->getOperand(1).getValueType() == MVT::i32 &&
-           "Expected index to be an i32 target constant!");
+           "Expected index to be a target constant!");
     break;
   case RISCVISD::TUPLE_INSERT:
-    assert(N->getNumOperands() == 3 && "Expected three operands!");
     assert(N->getOperand(2).getOpcode() == ISD::TargetConstant &&
-           N->getOperand(2).getValueType() == MVT::i32 &&
-           "Expected index to be an i32 target constant!");
+           "Expected index to be a target constant!");
     break;
   case RISCVISD::VQDOT_VL:
   case RISCVISD::VQDOTU_VL:
   case RISCVISD::VQDOTSU_VL: {
-    assert(N->getNumValues() == 1 && "Expected one result!");
-    assert(N->getNumOperands() == 5 && "Expected five operands!");
     EVT VT = N->getValueType(0);
     assert(VT.isScalableVector() && VT.getVectorElementType() == MVT::i32 &&
            "Expected result to be an i32 scalable vector");
@@ -52,13 +47,9 @@ void RISCVSelectionDAGInfo::verifyTargetNode(const SelectionDAG &DAG,
            "Expected result and first 3 operands to have the same type!");
     EVT MaskVT = N->getOperand(3).getValueType();
     assert(MaskVT.isScalableVector() &&
-           MaskVT.getVectorElementType() == MVT::i1 &&
            MaskVT.getVectorElementCount() == VT.getVectorElementCount() &&
            "Expected mask VT to be an i1 scalable vector with same number of "
            "elements as the result");
-    assert((N->getOperand(4).getValueType() == MVT::i32 ||
-            N->getOperand(4).getValueType() == MVT::i64) &&
-           "Expect VL operand to be i32 or i64");
     break;
   }
   }

llvm/lib/Target/Sparc/SparcInstrInfo.td

@@ -369,7 +369,7 @@ def callseq_start : SDNode<"ISD::CALLSEQ_START", SDT_SPCallSeqStart,
 def callseq_end   : SDNode<"ISD::CALLSEQ_END",   SDT_SPCallSeqEnd,
                            [SDNPHasChain, SDNPOptInGlue, SDNPOutGlue]>;
 
-def SDT_SPCall    : SDTypeProfile<0, -1, [SDTCisVT<0, i32>]>;
+def SDT_SPCall    : SDTypeProfile<0, -1, [SDTCisVT<0, iPTR>]>;
 def call          : SDNode<"SPISD::CALL", SDT_SPCall,
                            [SDNPHasChain, SDNPOptInGlue, SDNPOutGlue,
                             SDNPVariadic]>;