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[NFC][TableGen][DecoderEmitter] Eliminate indent for a few functions #148718

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Jul 14, 2025
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[NFC][TableGen][DecoderEmitter] Eliminate indent for a few functions #148718

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126 changes: 55 additions & 71 deletions llvm/utils/TableGen/DecoderEmitter.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -227,14 +227,14 @@ class DecoderEmitter {
// Emit the decoder state machine table. Returns a mask of MCD decoder ops
// that were emitted.
unsigned emitTable(formatted_raw_ostream &OS, DecoderTable &Table,
indent Indent, unsigned BitWidth, StringRef Namespace,
unsigned BitWidth, StringRef Namespace,
const EncodingIDsVec &EncodingIDs) const;
void emitInstrLenTable(formatted_raw_ostream &OS,
ArrayRef<unsigned> InstrLen) const;
void emitPredicateFunction(formatted_raw_ostream &OS,
PredicateSet &Predicates, indent Indent) const;
void emitDecoderFunction(formatted_raw_ostream &OS, DecoderSet &Decoders,
indent Indent) const;
PredicateSet &Predicates) const;
void emitDecoderFunction(formatted_raw_ostream &OS,
DecoderSet &Decoders) const;

// run - Output the code emitter
void run(raw_ostream &o);
Expand Down Expand Up @@ -833,8 +833,8 @@ unsigned Filter::usefulness() const {
// Emit the decoder state machine table. Returns a mask of MCD decoder ops
// that were emitted.
unsigned DecoderEmitter::emitTable(formatted_raw_ostream &OS,
DecoderTable &Table, indent Indent,
unsigned BitWidth, StringRef Namespace,
DecoderTable &Table, unsigned BitWidth,
StringRef Namespace,
const EncodingIDsVec &EncodingIDs) const {
// We'll need to be able to map from a decoded opcode into the corresponding
// EncodingID for this specific combination of BitWidth and Namespace. This
Expand All @@ -844,11 +844,9 @@ unsigned DecoderEmitter::emitTable(formatted_raw_ostream &OS,
for (const auto &EI : EncodingIDs)
OpcodeToEncodingID[EI.Opcode] = EI.EncodingID;

OS << Indent << "static const uint8_t DecoderTable" << Namespace << BitWidth
OS << "static const uint8_t DecoderTable" << Namespace << BitWidth
<< "[] = {\n";

Indent += 2;

// Emit ULEB128 encoded value to OS, returning the number of bytes emitted.
auto emitULEB128 = [](DecoderTable::const_iterator &I,
formatted_raw_ostream &OS) {
Expand Down Expand Up @@ -905,7 +903,7 @@ unsigned DecoderEmitter::emitTable(formatted_raw_ostream &OS,
PrintFatalError("Invalid decode table opcode: " + Twine((int)DecoderOp) +
" at index " + Twine(Pos));
case MCD::OPC_ExtractField: {
OS << Indent << "MCD::OPC_ExtractField, ";
OS << " MCD::OPC_ExtractField, ";

// ULEB128 encoded start value.
const char *ErrMsg = nullptr;
Expand All @@ -923,7 +921,7 @@ unsigned DecoderEmitter::emitTable(formatted_raw_ostream &OS,
case MCD::OPC_FilterValue:
case MCD::OPC_FilterValueOrFail: {
bool IsFail = DecoderOp == MCD::OPC_FilterValueOrFail;
OS << Indent << "MCD::OPC_FilterValue" << (IsFail ? "OrFail, " : ", ");
OS << " MCD::OPC_FilterValue" << (IsFail ? "OrFail, " : ", ");
// The filter value is ULEB128 encoded.
emitULEB128(I, OS);

Expand All @@ -937,7 +935,7 @@ unsigned DecoderEmitter::emitTable(formatted_raw_ostream &OS,
case MCD::OPC_CheckField:
case MCD::OPC_CheckFieldOrFail: {
bool IsFail = DecoderOp == MCD::OPC_CheckFieldOrFail;
OS << Indent << "MCD::OPC_CheckField" << (IsFail ? "OrFail, " : ", ");
OS << " MCD::OPC_CheckField" << (IsFail ? "OrFail, " : ", ");
// ULEB128 encoded start value.
emitULEB128(I, OS);
// 8-bit length.
Expand All @@ -957,7 +955,7 @@ unsigned DecoderEmitter::emitTable(formatted_raw_ostream &OS,
case MCD::OPC_CheckPredicateOrFail: {
bool IsFail = DecoderOp == MCD::OPC_CheckPredicateOrFail;

OS << Indent << "MCD::OPC_CheckPredicate" << (IsFail ? "OrFail, " : ", ");
OS << " MCD::OPC_CheckPredicate" << (IsFail ? "OrFail, " : ", ");
emitULEB128(I, OS);

if (!IsFail) {
Expand All @@ -977,7 +975,7 @@ unsigned DecoderEmitter::emitTable(formatted_raw_ostream &OS,
unsigned Opc = decodeULEB128(&*I, nullptr, EndPtr, &ErrMsg);
assert(ErrMsg == nullptr && "ULEB128 value too large!");

OS << Indent << "MCD::OPC_" << (IsTry ? "Try" : "") << "Decode"
OS << " MCD::OPC_" << (IsTry ? "Try" : "") << "Decode"
<< (IsFail ? "OrFail, " : ", ");
emitULEB128(I, OS);

Expand Down Expand Up @@ -1007,7 +1005,7 @@ unsigned DecoderEmitter::emitTable(formatted_raw_ostream &OS,
break;
}
case MCD::OPC_SoftFail: {
OS << Indent << "MCD::OPC_SoftFail, ";
OS << " MCD::OPC_SoftFail, ";
// Decode the positive mask.
const char *ErrMsg = nullptr;
uint64_t PositiveMask = decodeULEB128(&*I, nullptr, EndPtr, &ErrMsg);
Expand All @@ -1026,15 +1024,12 @@ unsigned DecoderEmitter::emitTable(formatted_raw_ostream &OS,
break;
}
case MCD::OPC_Fail:
OS << Indent << "MCD::OPC_Fail,\n";
OS << " MCD::OPC_Fail,\n";
break;
}
}
OS << Indent << "0\n";

Indent -= 2;

OS << Indent << "};\n\n";
OS << " 0\n";
OS << "};\n\n";

return OpcodeMask;
}
Expand All @@ -1048,27 +1043,23 @@ void DecoderEmitter::emitInstrLenTable(formatted_raw_ostream &OS,
}

void DecoderEmitter::emitPredicateFunction(formatted_raw_ostream &OS,
PredicateSet &Predicates,
indent Indent) const {
PredicateSet &Predicates) const {
// The predicate function is just a big switch statement based on the
// input predicate index.
OS << Indent << "static bool checkDecoderPredicate(unsigned Idx, "
<< "const FeatureBitset &Bits) {\n";
Indent += 2;
OS << Indent << "switch (Idx) {\n";
OS << Indent << "default: llvm_unreachable(\"Invalid index!\");\n";
OS << "static bool checkDecoderPredicate(unsigned Idx, const FeatureBitset "
"&Bits) {\n";
OS << " switch (Idx) {\n";
OS << " default: llvm_unreachable(\"Invalid index!\");\n";
for (const auto &[Index, Predicate] : enumerate(Predicates)) {
OS << Indent << "case " << Index << ":\n";
OS << Indent + 2 << "return (" << Predicate << ");\n";
OS << " case " << Index << ":\n";
OS << " return (" << Predicate << ");\n";
}
OS << Indent << "}\n";
Indent -= 2;
OS << Indent << "}\n\n";
OS << " }\n";
OS << "}\n\n";
}

void DecoderEmitter::emitDecoderFunction(formatted_raw_ostream &OS,
DecoderSet &Decoders,
indent Indent) const {
DecoderSet &Decoders) const {
// The decoder function is just a big switch statement or a table of function
// pointers based on the input decoder index.

Expand All @@ -1085,53 +1076,46 @@ void DecoderEmitter::emitDecoderFunction(formatted_raw_ostream &OS,
if (UseFnTableInDecodeToMCInst) {
// Emit a function for each case first.
for (const auto &[Index, Decoder] : enumerate(Decoders)) {
OS << Indent << "template <typename InsnType>\n";
OS << Indent << "DecodeStatus decodeFn" << Index << "(" << DecodeParams
<< ") {\n";
Indent += 2;
OS << Indent << TmpTypeDecl;
OS << Indent << "[[maybe_unused]] TmpType tmp;\n";
OS << "template <typename InsnType>\n";
OS << "DecodeStatus decodeFn" << Index << "(" << DecodeParams << ") {\n";
OS << " " << TmpTypeDecl;
OS << " [[maybe_unused]] TmpType tmp;\n";
OS << Decoder;
OS << Indent << "return S;\n";
Indent -= 2;
OS << Indent << "}\n\n";
OS << " return S;\n";
OS << "}\n\n";
}
}

OS << Indent << "// Handling " << Decoders.size() << " cases.\n";
OS << Indent << "template <typename InsnType>\n";
OS << Indent << "static DecodeStatus decodeToMCInst(unsigned Idx, "
<< DecodeParams << ") {\n";
Indent += 2;
OS << Indent << "DecodeComplete = true;\n";
OS << "// Handling " << Decoders.size() << " cases.\n";
OS << "template <typename InsnType>\n";
OS << "static DecodeStatus decodeToMCInst(unsigned Idx, " << DecodeParams
<< ") {\n";
OS << " DecodeComplete = true;\n";

if (UseFnTableInDecodeToMCInst) {
// Build a table of function pointers.
OS << Indent << "using DecodeFnTy = DecodeStatus (*)(" << DecodeParams
<< ");\n";
OS << Indent << "static constexpr DecodeFnTy decodeFnTable[] = {\n";
OS << " using DecodeFnTy = DecodeStatus (*)(" << DecodeParams << ");\n";
OS << " static constexpr DecodeFnTy decodeFnTable[] = {\n";
for (size_t Index : llvm::seq(Decoders.size()))
OS << Indent + 2 << "decodeFn" << Index << ",\n";
OS << Indent << "};\n";
OS << Indent << "if (Idx >= " << Decoders.size() << ")\n";
OS << Indent + 2 << "llvm_unreachable(\"Invalid index!\");\n";
OS << Indent
<< "return decodeFnTable[Idx](S, insn, MI, Address, Decoder, "
OS << " decodeFn" << Index << ",\n";
OS << " };\n";
OS << " if (Idx >= " << Decoders.size() << ")\n";
OS << " llvm_unreachable(\"Invalid index!\");\n";
OS << " return decodeFnTable[Idx](S, insn, MI, Address, Decoder, "
"DecodeComplete);\n";
} else {
OS << Indent << TmpTypeDecl;
OS << Indent << "TmpType tmp;\n";
OS << Indent << "switch (Idx) {\n";
OS << Indent << "default: llvm_unreachable(\"Invalid index!\");\n";
OS << " " << TmpTypeDecl;
OS << " TmpType tmp;\n";
OS << " switch (Idx) {\n";
OS << " default: llvm_unreachable(\"Invalid index!\");\n";
for (const auto &[Index, Decoder] : enumerate(Decoders)) {
OS << Indent << "case " << Index << ":\n";
OS << " case " << Index << ":\n";
OS << Decoder;
OS << Indent + 2 << "return S;\n";
OS << " return S;\n";
}
OS << Indent << "}\n";
OS << " }\n";
}
Indent -= 2;
OS << Indent << "}\n";
OS << "}\n";
}

// Populates the field of the insn given the start position and the number of
Expand Down Expand Up @@ -2673,7 +2657,7 @@ namespace {
TableInfo.Table.push_back(MCD::OPC_Fail);

// Print the table to the output stream.
OpcodeMask |= emitTable(OS, TableInfo.Table, indent(0), FC.getBitWidth(),
OpcodeMask |= emitTable(OS, TableInfo.Table, FC.getBitWidth(),
DecoderNamespace, EncodingIDs);
}

Expand All @@ -2689,10 +2673,10 @@ namespace {

// Emit the predicate function.
if (HasCheckPredicate)
emitPredicateFunction(OS, TableInfo.Predicates, indent(0));
emitPredicateFunction(OS, TableInfo.Predicates);

// Emit the decoder function.
emitDecoderFunction(OS, TableInfo.Decoders, indent(0));
emitDecoderFunction(OS, TableInfo.Decoders);

// Emit the main entry point for the decoder, decodeInstruction().
emitDecodeInstruction(OS, IsVarLenInst, OpcodeMask);
Expand Down
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