[TableGen][DecoderEmitter] Factor populateFixedLenEncoding (NFC) (#154511)

Also drop the debug code under `#if 0` and a seemingly outdated comment.
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Sergei Barannikov 2025-08-20 14:34:59 +03:00 committed by GitHub
parent b01f05977c
commit 19ac1ff56e
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@ -156,7 +156,14 @@ public:
Name = (EncodingDef->getName() + Twine(':')).str();
Name.append(InstDef->getName());
BitWidth = populateEncoding();
StringRef DecoderMethod = EncodingDef->getValueAsString("DecoderMethod");
if (!DecoderMethod.empty()) {
bool HasCompleteDecoder =
EncodingDef->getValueAsBit("hasCompleteDecoder");
Operands.push_back(OperandInfo(DecoderMethod.str(), HasCompleteDecoder));
}
populateEncoding();
}
/// Returns the Record this encoding originates from.
@ -175,9 +182,9 @@ public:
ArrayRef<OperandInfo> getOperands() const { return Operands; }
private:
void populateVarLenEncoding();
unsigned populateEncoding();
void populateVarLenEncoding(const VarLenInst &VLI);
void populateFixedLenEncoding(const BitsInit &Bits);
void populateEncoding();
};
typedef std::vector<uint32_t> FixupList;
@ -1862,9 +1869,7 @@ OperandInfo getOpInfo(const Record *TypeRecord) {
return OperandInfo(findOperandDecoderMethod(TypeRecord), HasCompleteDecoder);
}
void InstructionEncoding::populateVarLenEncoding() {
const RecordVal *RV = EncodingDef->getValue("Inst");
VarLenInst VLI(cast<DagInit>(RV->getValue()), RV);
void InstructionEncoding::populateVarLenEncoding(const VarLenInst &VLI) {
SmallVector<int> TiedTo;
for (const auto &[Idx, Op] : enumerate(Inst->Operands)) {
@ -1961,28 +1966,9 @@ static void addOneOperandFields(const Record *EncodingDef, const BitsInit &Bits,
}
}
unsigned InstructionEncoding::populateEncoding() {
bool IsVarLenInst = isa<DagInit>(EncodingDef->getValueInit("Inst"));
void InstructionEncoding::populateFixedLenEncoding(const BitsInit &Bits) {
const Record &Def = *Inst->TheDef;
const BitsInit &Bits = getBitsField(*EncodingDef, "Inst");
assert(!Bits.allInComplete() &&
"Invalid encodings should have been filtered out");
// If the instruction has specified a custom decoding hook, use that instead
// of trying to auto-generate the decoder.
StringRef InstDecoder = EncodingDef->getValueAsString("DecoderMethod");
if (!InstDecoder.empty()) {
bool HasCompleteInstDecoder =
EncodingDef->getValueAsBit("hasCompleteDecoder");
Operands.push_back(OperandInfo(InstDecoder.str(), HasCompleteInstDecoder));
return Bits.getNumBits();
}
// Generate a description of the operand of the instruction that we know
// how to decode automatically.
// FIXME: We'll need to have a way to manually override this as needed.
// Gather the outputs/inputs of the instruction, so we can find their
// positions in the encoding. This assumes for now that they appear in the
// MCInst in the order that they're listed.
@ -2015,108 +2001,100 @@ unsigned InstructionEncoding::populateEncoding() {
}
}
if (IsVarLenInst) {
populateVarLenEncoding();
} else {
// For each operand, see if we can figure out where it is encoded.
for (const auto &Op : InOutOperands) {
const Init *OpInit = Op.first;
StringRef OpName = Op.second;
// For each operand, see if we can figure out where it is encoded.
for (const auto &Op : InOutOperands) {
const Init *OpInit = Op.first;
StringRef OpName = Op.second;
// We're ready to find the instruction encoding locations for this
// operand.
// We're ready to find the instruction encoding locations for this
// operand.
// First, find the operand type ("OpInit"), and sub-op names
// ("SubArgDag") if present.
const DagInit *SubArgDag = dyn_cast<DagInit>(OpInit);
if (SubArgDag)
OpInit = SubArgDag->getOperator();
const Record *OpTypeRec = cast<DefInit>(OpInit)->getDef();
// Lookup the sub-operands from the operand type record (note that only
// Operand subclasses have MIOperandInfo, see CodeGenInstruction.cpp).
const DagInit *SubOps = OpTypeRec->isSubClassOf("Operand")
? OpTypeRec->getValueAsDag("MIOperandInfo")
: nullptr;
// First, find the operand type ("OpInit"), and sub-op names
// ("SubArgDag") if present.
const DagInit *SubArgDag = dyn_cast<DagInit>(OpInit);
if (SubArgDag)
OpInit = SubArgDag->getOperator();
const Record *OpTypeRec = cast<DefInit>(OpInit)->getDef();
// Lookup the sub-operands from the operand type record (note that only
// Operand subclasses have MIOperandInfo, see CodeGenInstruction.cpp).
const DagInit *SubOps = OpTypeRec->isSubClassOf("Operand")
? OpTypeRec->getValueAsDag("MIOperandInfo")
: nullptr;
// Lookup the decoder method and construct a new OperandInfo to hold our
// result.
OperandInfo OpInfo = getOpInfo(OpTypeRec);
// Lookup the decoder method and construct a new OperandInfo to hold our
// result.
OperandInfo OpInfo = getOpInfo(OpTypeRec);
// If we have named sub-operands...
if (SubArgDag) {
// Then there should not be a custom decoder specified on the top-level
// type.
if (!OpInfo.Decoder.empty()) {
PrintError(EncodingDef,
"DecoderEmitter: operand \"" + OpName + "\" has type \"" +
OpInit->getAsString() +
"\" with a custom DecoderMethod, but also named "
"sub-operands.");
continue;
}
// Decode each of the sub-ops separately.
assert(SubOps && SubArgDag->getNumArgs() == SubOps->getNumArgs());
for (const auto &[I, Arg] : enumerate(SubOps->getArgs())) {
StringRef SubOpName = SubArgDag->getArgNameStr(I);
OperandInfo SubOpInfo = getOpInfo(cast<DefInit>(Arg)->getDef());
addOneOperandFields(EncodingDef, Bits, TiedNames, SubOpName,
SubOpInfo);
Operands.push_back(std::move(SubOpInfo));
}
// If we have named sub-operands...
if (SubArgDag) {
// Then there should not be a custom decoder specified on the top-level
// type.
if (!OpInfo.Decoder.empty()) {
PrintError(EncodingDef,
"DecoderEmitter: operand \"" + OpName + "\" has type \"" +
OpInit->getAsString() +
"\" with a custom DecoderMethod, but also named "
"sub-operands.");
continue;
}
// Otherwise, if we have an operand with sub-operands, but they aren't
// named...
if (SubOps && OpInfo.Decoder.empty()) {
// If it's a single sub-operand, and no custom decoder, use the decoder
// from the one sub-operand.
if (SubOps->getNumArgs() == 1)
OpInfo = getOpInfo(cast<DefInit>(SubOps->getArg(0))->getDef());
// Decode each of the sub-ops separately.
assert(SubOps && SubArgDag->getNumArgs() == SubOps->getNumArgs());
for (const auto &[I, Arg] : enumerate(SubOps->getArgs())) {
StringRef SubOpName = SubArgDag->getArgNameStr(I);
OperandInfo SubOpInfo = getOpInfo(cast<DefInit>(Arg)->getDef());
// If we have multiple sub-ops, there'd better have a custom
// decoder. (Otherwise we don't know how to populate them properly...)
if (SubOps->getNumArgs() > 1) {
PrintError(EncodingDef,
"DecoderEmitter: operand \"" + OpName +
"\" uses MIOperandInfo with multiple ops, but doesn't "
"have a custom decoder!");
debugDumpRecord(*EncodingDef);
continue;
}
addOneOperandFields(EncodingDef, Bits, TiedNames, SubOpName, SubOpInfo);
Operands.push_back(std::move(SubOpInfo));
}
addOneOperandFields(EncodingDef, Bits, TiedNames, OpName, OpInfo);
// FIXME: it should be an error not to find a definition for a given
// operand, rather than just failing to add it to the resulting
// instruction! (This is a longstanding bug, which will be addressed in an
// upcoming change.)
if (OpInfo.numFields() > 0)
Operands.push_back(std::move(OpInfo));
continue;
}
}
#if 0
LLVM_DEBUG({
// Dumps the instruction encoding bits.
dumpBits(errs(), Bits);
// Otherwise, if we have an operand with sub-operands, but they aren't
// named...
if (SubOps && OpInfo.Decoder.empty()) {
// If it's a single sub-operand, and no custom decoder, use the decoder
// from the one sub-operand.
if (SubOps->getNumArgs() == 1)
OpInfo = getOpInfo(cast<DefInit>(SubOps->getArg(0))->getDef());
errs() << '\n';
// Dumps the list of operand info.
for (unsigned i = 0, e = Inst->Operands.size(); i != e; ++i) {
const CGIOperandList::OperandInfo &Info = Inst->Operands[i];
const std::string &OperandName = Info.Name;
const Record &OperandDef = *Info.Rec;
errs() << "\t" << OperandName << " (" << OperandDef.getName() << ")\n";
// If we have multiple sub-ops, there'd better have a custom
// decoder. (Otherwise we don't know how to populate them properly...)
if (SubOps->getNumArgs() > 1) {
PrintError(EncodingDef,
"DecoderEmitter: operand \"" + OpName +
"\" uses MIOperandInfo with multiple ops, but doesn't "
"have a custom decoder!");
debugDumpRecord(*EncodingDef);
continue;
}
});
#endif
}
return Bits.getNumBits();
addOneOperandFields(EncodingDef, Bits, TiedNames, OpName, OpInfo);
// FIXME: it should be an error not to find a definition for a given
// operand, rather than just failing to add it to the resulting
// instruction! (This is a longstanding bug, which will be addressed in an
// upcoming change.)
if (OpInfo.numFields() > 0)
Operands.push_back(std::move(OpInfo));
}
}
void InstructionEncoding::populateEncoding() {
const RecordVal *InstField = EncodingDef->getValue("Inst");
if (const auto *DI = dyn_cast<DagInit>(InstField->getValue())) {
VarLenInst VLI(DI, InstField);
BitWidth = VLI.size();
// If the encoding has a custom decoder, don't bother parsing the operands.
if (Operands.empty())
populateVarLenEncoding(VLI);
} else {
const auto *BI = cast<BitsInit>(InstField->getValue());
BitWidth = BI->getNumBits();
// If the encoding has a custom decoder, don't bother parsing the operands.
if (Operands.empty())
populateFixedLenEncoding(*BI);
}
}
// emitFieldFromInstruction - Emit the templated helper function