[LLVM][TableGen] Parameterize NumToSkip in DecoderEmitter

llvm/lib/Target/AArch64/CMakeLists.txt

@@ -7,7 +7,7 @@ tablegen(LLVM AArch64GenAsmWriter.inc -gen-asm-writer)
 tablegen(LLVM AArch64GenAsmWriter1.inc -gen-asm-writer -asmwriternum=1)
 tablegen(LLVM AArch64GenCallingConv.inc -gen-callingconv)
 tablegen(LLVM AArch64GenDAGISel.inc -gen-dag-isel)
-tablegen(LLVM AArch64GenDisassemblerTables.inc -gen-disassembler)
+tablegen(LLVM AArch64GenDisassemblerTables.inc -gen-disassembler --num-to-skip-size=3)
 tablegen(LLVM AArch64GenFastISel.inc -gen-fast-isel)
 tablegen(LLVM AArch64GenGlobalISel.inc -gen-global-isel)
 tablegen(LLVM AArch64GenO0PreLegalizeGICombiner.inc -gen-global-isel-combiner

llvm/lib/Target/AArch64/Disassembler/AArch64Disassembler.cpp

@@ -244,9 +244,9 @@ DecodeStatus AArch64Disassembler::getInstruction(MCInst &MI, uint64_t &Size,
   uint32_t Insn =
       (Bytes[3] << 24) | (Bytes[2] << 16) | (Bytes[1] << 8) | (Bytes[0] << 0);
 
-  const uint8_t *Tables[] = {DecoderTable32, DecoderTableFallback32};
+  const DecoderTable3Bytes Tables[] = {DecoderTable32, DecoderTableFallback32};
 
-  for (const auto *Table : Tables) {
+  for (const auto Table : Tables) {
     DecodeStatus Result =
         decodeInstruction(Table, MI, Insn, Address, this, STI);
 

llvm/lib/Target/AMDGPU/Disassembler/AMDGPUDisassembler.cpp

@@ -487,6 +487,47 @@ static DecodeStatus decodeVersionImm(MCInst &Inst, unsigned Imm,
 //
 //===----------------------------------------------------------------------===//
 
+template <typename InsnType>
+static DecodeStatus tryDecodeInst(DecoderTable2Bytes Table, MCInst &MI,
+                                  InsnType Inst, uint64_t Address,
+                                  raw_ostream &Comments,
+                                  const AMDGPUDisassembler *Asm) {
+  assert(MI.getOpcode() == 0);
+  assert(MI.getNumOperands() == 0);
+  MCInst TmpInst;
+  Asm->setHasLiteral(false);
+  const auto SavedBytes = Asm->getBytes();
+
+  SmallString<64> LocalComments;
+  raw_svector_ostream LocalCommentStream(LocalComments);
+  Asm->CommentStream = &LocalCommentStream;
+
+  DecodeStatus Res = decodeInstruction(Table, TmpInst, Inst, Address, Asm,
+                                       Asm->getSubtargetInfo());
+
+  Asm->CommentStream = nullptr;
+
+  if (Res != MCDisassembler::Fail) {
+    MI = TmpInst;
+    Comments << LocalComments;
+    return MCDisassembler::Success;
+  }
+  Asm->setBytes(SavedBytes);
+  return MCDisassembler::Fail;
+}
+
+template <typename InsnType>
+static DecodeStatus
+tryDecodeInst(DecoderTable2Bytes Table1, DecoderTable2Bytes Table2, MCInst &MI,
+              InsnType Inst, uint64_t Address, raw_ostream &Comments,
+              const AMDGPUDisassembler *Asm) {
+  for (DecoderTable2Bytes T : {Table1, Table2}) {
+    if (DecodeStatus Res = tryDecodeInst(T, MI, Inst, Address, Comments, Asm))
+      return Res;
+  }
+  return MCDisassembler::Fail;
+}
+
 template <typename T> static inline T eatBytes(ArrayRef<uint8_t>& Bytes) {
   assert(Bytes.size() >= sizeof(T));
   const auto Res =
@@ -539,16 +580,16 @@ DecodeStatus AMDGPUDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
 
       if (isGFX11() &&
           tryDecodeInst(DecoderTableGFX1196, DecoderTableGFX11_FAKE1696, MI,
-                        DecW, Address, CS))
+                        DecW, Address, CS, this))
         break;
 
       if (isGFX12() &&
           tryDecodeInst(DecoderTableGFX1296, DecoderTableGFX12_FAKE1696, MI,
-                        DecW, Address, CS))
+                        DecW, Address, CS, this))
         break;
 
       if (isGFX12() &&
-          tryDecodeInst(DecoderTableGFX12W6496, MI, DecW, Address, CS))
+          tryDecodeInst(DecoderTableGFX12W6496, MI, DecW, Address, CS, this))
         break;
 
       // Reinitialize Bytes
@@ -557,7 +598,7 @@ DecodeStatus AMDGPUDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
     } else if (Bytes.size() >= 16 &&
                STI.hasFeature(AMDGPU::FeatureGFX950Insts)) {
       DecoderUInt128 DecW = eat16Bytes(Bytes);
-      if (tryDecodeInst(DecoderTableGFX940128, MI, DecW, Address, CS))
+      if (tryDecodeInst(DecoderTableGFX940128, MI, DecW, Address, CS, this))
         break;
 
       // Reinitialize Bytes
@@ -568,58 +609,61 @@ DecodeStatus AMDGPUDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
       const uint64_t QW = eatBytes<uint64_t>(Bytes);
 
       if (STI.hasFeature(AMDGPU::FeatureGFX10_BEncoding) &&
-          tryDecodeInst(DecoderTableGFX10_B64, MI, QW, Address, CS))
+          tryDecodeInst(DecoderTableGFX10_B64, MI, QW, Address, CS, this))
         break;
 
       if (STI.hasFeature(AMDGPU::FeatureUnpackedD16VMem) &&
-          tryDecodeInst(DecoderTableGFX80_UNPACKED64, MI, QW, Address, CS))
+          tryDecodeInst(DecoderTableGFX80_UNPACKED64, MI, QW, Address, CS,
+                        this))
         break;
 
       if (STI.hasFeature(AMDGPU::FeatureGFX950Insts) &&
-          tryDecodeInst(DecoderTableGFX95064, MI, QW, Address, CS))
+          tryDecodeInst(DecoderTableGFX95064, MI, QW, Address, CS, this))
         break;
 
       // Some GFX9 subtargets repurposed the v_mad_mix_f32, v_mad_mixlo_f16 and
       // v_mad_mixhi_f16 for FMA variants. Try to decode using this special
       // table first so we print the correct name.
       if (STI.hasFeature(AMDGPU::FeatureFmaMixInsts) &&
-          tryDecodeInst(DecoderTableGFX9_DL64, MI, QW, Address, CS))
+          tryDecodeInst(DecoderTableGFX9_DL64, MI, QW, Address, CS, this))
         break;
 
       if (STI.hasFeature(AMDGPU::FeatureGFX940Insts) &&
-          tryDecodeInst(DecoderTableGFX94064, MI, QW, Address, CS))
+          tryDecodeInst(DecoderTableGFX94064, MI, QW, Address, CS, this))
         break;
 
       if (STI.hasFeature(AMDGPU::FeatureGFX90AInsts) &&
-          tryDecodeInst(DecoderTableGFX90A64, MI, QW, Address, CS))
+          tryDecodeInst(DecoderTableGFX90A64, MI, QW, Address, CS, this))
         break;
 
       if ((isVI() || isGFX9()) &&
-          tryDecodeInst(DecoderTableGFX864, MI, QW, Address, CS))
+          tryDecodeInst(DecoderTableGFX864, MI, QW, Address, CS, this))
         break;
 
-      if (isGFX9() && tryDecodeInst(DecoderTableGFX964, MI, QW, Address, CS))
+      if (isGFX9() &&
+          tryDecodeInst(DecoderTableGFX964, MI, QW, Address, CS, this))
         break;
 
-      if (isGFX10() && tryDecodeInst(DecoderTableGFX1064, MI, QW, Address, CS))
+      if (isGFX10() &&
+          tryDecodeInst(DecoderTableGFX1064, MI, QW, Address, CS, this))
         break;
 
       if (isGFX12() &&
           tryDecodeInst(DecoderTableGFX1264, DecoderTableGFX12_FAKE1664, MI, QW,
-                        Address, CS))
+                        Address, CS, this))
         break;
 
       if (isGFX11() &&
           tryDecodeInst(DecoderTableGFX1164, DecoderTableGFX11_FAKE1664, MI, QW,
-                        Address, CS))
+                        Address, CS, this))
         break;
 
       if (isGFX11() &&
-          tryDecodeInst(DecoderTableGFX11W6464, MI, QW, Address, CS))
+          tryDecodeInst(DecoderTableGFX11W6464, MI, QW, Address, CS, this))
         break;
 
       if (isGFX12() &&
-          tryDecodeInst(DecoderTableGFX12W6464, MI, QW, Address, CS))
+          tryDecodeInst(DecoderTableGFX12W6464, MI, QW, Address, CS, this))
         break;
 
       // Reinitialize Bytes
@@ -631,38 +675,40 @@ DecodeStatus AMDGPUDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
       const uint32_t DW = eatBytes<uint32_t>(Bytes);
 
       if ((isVI() || isGFX9()) &&
-          tryDecodeInst(DecoderTableGFX832, MI, DW, Address, CS))
+          tryDecodeInst(DecoderTableGFX832, MI, DW, Address, CS, this))
         break;
 
-      if (tryDecodeInst(DecoderTableAMDGPU32, MI, DW, Address, CS))
+      if (tryDecodeInst(DecoderTableAMDGPU32, MI, DW, Address, CS, this))
         break;
 
-      if (isGFX9() && tryDecodeInst(DecoderTableGFX932, MI, DW, Address, CS))
+      if (isGFX9() &&
+          tryDecodeInst(DecoderTableGFX932, MI, DW, Address, CS, this))
         break;
 
       if (STI.hasFeature(AMDGPU::FeatureGFX950Insts) &&
-          tryDecodeInst(DecoderTableGFX95032, MI, DW, Address, CS))
+          tryDecodeInst(DecoderTableGFX95032, MI, DW, Address, CS, this))
         break;
 
       if (STI.hasFeature(AMDGPU::FeatureGFX90AInsts) &&
-          tryDecodeInst(DecoderTableGFX90A32, MI, DW, Address, CS))
+          tryDecodeInst(DecoderTableGFX90A32, MI, DW, Address, CS, this))
         break;
 
       if (STI.hasFeature(AMDGPU::FeatureGFX10_BEncoding) &&
-          tryDecodeInst(DecoderTableGFX10_B32, MI, DW, Address, CS))
+          tryDecodeInst(DecoderTableGFX10_B32, MI, DW, Address, CS, this))
         break;
 
-      if (isGFX10() && tryDecodeInst(DecoderTableGFX1032, MI, DW, Address, CS))
+      if (isGFX10() &&
+          tryDecodeInst(DecoderTableGFX1032, MI, DW, Address, CS, this))
         break;
 
       if (isGFX11() &&
           tryDecodeInst(DecoderTableGFX1132, DecoderTableGFX11_FAKE1632, MI, DW,
-                        Address, CS))
+                        Address, CS, this))
         break;
 
       if (isGFX12() &&
           tryDecodeInst(DecoderTableGFX1232, DecoderTableGFX12_FAKE1632, MI, DW,
-                        Address, CS))
+                        Address, CS, this))
         break;
     }
 

llvm/lib/Target/AMDGPU/Disassembler/AMDGPUDisassembler.h

@@ -128,44 +128,6 @@ class AMDGPUDisassembler : public MCDisassembler {
 
   MCOperand errOperand(unsigned V, const Twine& ErrMsg) const;
 
-  template <typename InsnType>
-  DecodeStatus tryDecodeInst(const uint8_t *Table, MCInst &MI, InsnType Inst,
-                             uint64_t Address, raw_ostream &Comments) const {
-    assert(MI.getOpcode() == 0);
-    assert(MI.getNumOperands() == 0);
-    MCInst TmpInst;
-    HasLiteral = false;
-    const auto SavedBytes = Bytes;
-
-    SmallString<64> LocalComments;
-    raw_svector_ostream LocalCommentStream(LocalComments);
-    CommentStream = &LocalCommentStream;
-
-    DecodeStatus Res =
-        decodeInstruction(Table, TmpInst, Inst, Address, this, STI);
-
-    CommentStream = nullptr;
-
-    if (Res != Fail) {
-      MI = TmpInst;
-      Comments << LocalComments;
-      return MCDisassembler::Success;
-    }
-    Bytes = SavedBytes;
-    return MCDisassembler::Fail;
-  }
-
-  template <typename InsnType>
-  DecodeStatus tryDecodeInst(const uint8_t *Table1, const uint8_t *Table2,
-                             MCInst &MI, InsnType Inst, uint64_t Address,
-                             raw_ostream &Comments) const {
-    for (const uint8_t *T : {Table1, Table2}) {
-      if (DecodeStatus Res = tryDecodeInst(T, MI, Inst, Address, Comments))
-        return Res;
-    }
-    return MCDisassembler::Fail;
-  }
-
   Expected<bool> onSymbolStart(SymbolInfoTy &Symbol, uint64_t &Size,
                                ArrayRef<uint8_t> Bytes,
                                uint64_t Address) const override;
@@ -294,6 +256,10 @@ class AMDGPUDisassembler : public MCDisassembler {
   bool hasKernargPreload() const;
 
   bool isMacDPP(MCInst &MI) const;
+
+  void setHasLiteral(bool Val) const { HasLiteral = Val; }
+  void setBytes(ArrayRef<uint8_t> Val) const { Bytes = Val; }
+  ArrayRef<uint8_t> getBytes() const { return Bytes; }
 };
 
 //===----------------------------------------------------------------------===//

llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp

@@ -809,25 +809,20 @@ DecodeStatus ARMDisassembler::getARMInstruction(MCInst &MI, uint64_t &Size,
     return checkDecodedInstruction(MI, Size, Address, CS, Insn, Result);
   }
 
-  struct DecodeTable {
-    const uint8_t *P;
-    bool DecodePred;
-  };
-
-  const DecodeTable Tables[] = {
+  constexpr std::pair<DecoderTable2Bytes, bool> Tables[] = {
       {DecoderTableVFP32, false},      {DecoderTableVFPV832, false},
       {DecoderTableNEONData32, true},  {DecoderTableNEONLoadStore32, true},
       {DecoderTableNEONDup32, true},   {DecoderTablev8NEON32, false},
       {DecoderTablev8Crypto32, false},
   };
 
-  for (auto Table : Tables) {
-    Result = decodeInstruction(Table.P, MI, Insn, Address, this, STI);
+  for (auto [Table, DecodePred] : Tables) {
+    Result = decodeInstruction(Table, MI, Insn, Address, this, STI);
     if (Result != MCDisassembler::Fail) {
       Size = 4;
       // Add a fake predicate operand, because we share these instruction
       // definitions with Thumb2 where these instructions are predicable.
-      if (Table.DecodePred && !DecodePredicateOperand(MI, 0xE, Address, this))
+      if (DecodePred && !DecodePredicateOperand(MI, 0xE, Address, this))
         return MCDisassembler::Fail;
       return Result;
     }
@@ -1254,9 +1249,9 @@ DecodeStatus ARMDisassembler::getThumbInstruction(MCInst &MI, uint64_t &Size,
   }
 
   uint32_t Coproc = fieldFromInstruction(Insn32, 8, 4);
-  const uint8_t *DecoderTable = ARM::isCDECoproc(Coproc, STI)
-                                    ? DecoderTableThumb2CDE32
-                                    : DecoderTableThumb2CoProc32;
+  const auto DecoderTable = ARM::isCDECoproc(Coproc, STI)
+                                ? DecoderTableThumb2CDE32
+                                : DecoderTableThumb2CoProc32;
   Result =
       decodeInstruction(DecoderTable, MI, Insn32, Address, this, STI);
   if (Result != MCDisassembler::Fail) {

llvm/lib/Target/AVR/Disassembler/AVRDisassembler.cpp

@@ -458,8 +458,7 @@ static DecodeStatus readInstruction32(ArrayRef<uint8_t> Bytes, uint64_t Address,
   return MCDisassembler::Success;
 }
 
-static const uint8_t *getDecoderTable(uint64_t Size) {
-
+static DecoderTable2Bytes getDecoderTable(uint64_t Size) {
   switch (Size) {
   case 2:
     return DecoderTable16;

llvm/lib/Target/Hexagon/Disassembler/HexagonDisassembler.cpp

@@ -327,7 +327,7 @@ DecodeStatus HexagonDisassembler::getSingleInstruction(MCInst &MI, MCInst &MCB,
   if ((Instruction & HexagonII::INST_PARSE_MASK) ==
       HexagonII::INST_PARSE_DUPLEX) {
     unsigned duplexIClass;
-    uint8_t const *DecodeLow, *DecodeHigh;
+    DecoderTable2Bytes DecodeLow, DecodeHigh;
     duplexIClass = ((Instruction >> 28) & 0xe) | ((Instruction >> 13) & 0x1);
     switch (duplexIClass) {
     default:

llvm/lib/Target/MSP430/Disassembler/MSP430Disassembler.cpp

@@ -201,7 +201,7 @@ static AddrMode DecodeDstAddrMode(unsigned Insn) {
   return Ad ? amIndexed : amRegister;
 }
 
-static const uint8_t *getDecoderTable(AddrMode SrcAM, unsigned Words) {
+static DecoderTable2Bytes getDecoderTable(AddrMode SrcAM, unsigned Words) {
   assert(0 < Words && Words < 4 && "Incorrect number of words");
   switch (SrcAM) {
   default:
@@ -308,7 +308,8 @@ DecodeStatus MSP430Disassembler::getInstructionII(MCInst &MI, uint64_t &Size,
     break;
   }
 
-  const uint8_t *DecoderTable = Words == 2 ? DecoderTable32 : DecoderTable16;
+  DecoderTable2Bytes DecoderTable =
+      Words == 2 ? DecoderTable32 : DecoderTable16;
   DecodeStatus Result = decodeInstruction(DecoderTable, MI, Insn, Address,
                                           this, STI);
   if (Result != MCDisassembler::Fail) {

llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp

@@ -675,7 +675,7 @@ void RISCVDisassembler::addSPOperands(MCInst &MI) const {
 namespace {
 
 struct DecoderListEntry {
-  const uint8_t *Table;
+  DecoderTable2Bytes Table;
   FeatureBitset ContainedFeatures;
   const char *Desc;
 

llvm/lib/Target/SystemZ/Disassembler/SystemZDisassembler.cpp

@@ -331,7 +331,7 @@ DecodeStatus SystemZDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
     return MCDisassembler::Fail;
 
   // The top 2 bits of the first byte specify the size.
-  const uint8_t *Table;
+  DecoderTable2Bytes Table;
   if (Bytes[0] < 0x40) {
     Size = 2;
     Table = DecoderTable16;

llvm/test/TableGen/VarLenDecoder.td

@@ -47,9 +47,9 @@ def FOO32 : MyVarInst<MemOp32> {
 }
 
 // CHECK:      MCD::OPC_ExtractField, 3, 5,  // Inst{7-3} ...
-// CHECK-NEXT: MCD::OPC_FilterValue, 8, 4, 0, 0, // Skip to: 12
+// CHECK-NEXT: MCD::OPC_FilterValue, 8, 4, 0, // Skip to: 11
 // CHECK-NEXT: MCD::OPC_Decode, {{[0-9]+}}, {{[0-9]+}}, 0, // Opcode: FOO16
-// CHECK-NEXT: MCD::OPC_FilterValue, 9, 4, 0, 0, // Skip to: 21
+// CHECK-NEXT: MCD::OPC_FilterValue, 9, 4, 0, // Skip to: 19
 // CHECK-NEXT: MCD::OPC_Decode, {{[0-9]+}}, {{[0-9]+}}, 1, // Opcode: FOO32
 // CHECK-NEXT: MCD::OPC_Fail,