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[NFC][TableGen] Adopt CodeGenHelpers in SubtargetEmitter #163820

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b279435
[NFC][TableGen] Adopt CodeGenHelpers in SubtargetEmitter
jurahul Oct 16, 2025
6f29332
Fix typo in comment
jurahul Oct 23, 2025
c36d683
Review feedback
jurahul Nov 5, 2025
344ed20
Review feedback: use scopes instead of close
jurahul Nov 5, 2025
cc25bd3
Merge branch 'main' into nfc_adropt_ifdef_ns_emitter_subtarget_emitter
jurahul Nov 5, 2025
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44 changes: 37 additions & 7 deletions llvm/include/llvm/TableGen/CodeGenHelpers.h
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Original file line number Diff line number Diff line change
Expand Up @@ -21,18 +21,37 @@

namespace llvm {

// Simple RAII helper for emitting ifdef-undef-endif scope.
// Simple RAII helper for emitting ifdef-undef-endif scope. `LateUndef` controls
// whether the undef is emitted at the start of the scope (false) or at the end
// of the scope (true).
class IfDefEmitter {
public:
IfDefEmitter(raw_ostream &OS, StringRef Name) : Name(Name.str()), OS(OS) {
OS << "#ifdef " << Name << "\n"
<< "#undef " << Name << "\n\n";
IfDefEmitter(raw_ostream &OS, StringRef Name, bool LateUndef = false)
: Name(Name.str()), OS(OS), LateUndef(LateUndef) {
OS << "#ifdef " << Name << "\n";
if (!LateUndef)
OS << "#undef " << Name << "\n";
OS << "\n";
}
~IfDefEmitter() { close(); }

// Explicit function to close the ifdef scopes.
void close() {
if (Closed)
return;

OS << "\n";
if (LateUndef)
OS << "#undef " << Name << "\n";
OS << "#endif // " << Name << "\n\n";
Closed = true;
}
~IfDefEmitter() { OS << "\n#endif // " << Name << "\n\n"; }

private:
std::string Name;
raw_ostream &OS;
bool LateUndef;
bool Closed = false;
};

// Simple RAII helper for emitting header include guard (ifndef-define-endif).
Expand All @@ -43,11 +62,20 @@ class IncludeGuardEmitter {
OS << "#ifndef " << Name << "\n"
<< "#define " << Name << "\n\n";
}
~IncludeGuardEmitter() { OS << "\n#endif // " << Name << "\n"; }
~IncludeGuardEmitter() { close(); }

// Explicit function to close the ifdef scopes.
void close() {
if (Closed)
return;
OS << "\n#endif // " << Name << "\n\n";
Closed = true;
}

private:
std::string Name;
raw_ostream &OS;
bool Closed = false;
};

// Simple RAII helper for emitting namespace scope. Name can be a single
Expand All @@ -65,7 +93,9 @@ class NamespaceEmitter {

// Explicit function to close the namespace scopes.
void close() {
if (!Closed && !Name.empty())
if (Closed)
return;
if (!Name.empty())
OS << "\n} // namespace " << Name << "\n";
Closed = true;
}
Expand Down
165 changes: 82 additions & 83 deletions llvm/utils/TableGen/SubtargetEmitter.cpp
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@
#include "llvm/Support/Debug.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/TableGen/CodeGenHelpers.h"
#include "llvm/TableGen/Error.h"
#include "llvm/TableGen/Record.h"
#include "llvm/TableGen/StringToOffsetTable.h"
Expand Down Expand Up @@ -75,7 +76,15 @@ class SubtargetEmitter : TargetFeaturesEmitter {
CodeGenTarget TGT;
CodeGenSchedModels &SchedModels;

FeatureMapTy emitEnums(raw_ostream &OS);
void emitSubtargetInfoMacroCalls(raw_ostream &OS);
std::tuple<unsigned, unsigned, unsigned>
emitMCDesc(raw_ostream &OS, const FeatureMapTy &FeatureMap);
void emitTargetDesc(raw_ostream &OS);
void emitHeader(raw_ostream &OS);
void emitCtor(raw_ostream &OS, unsigned NumNames, unsigned NumFeatures,
unsigned NumProcs);

unsigned featureKeyValues(raw_ostream &OS, const FeatureMapTy &FeatureMap);
unsigned cpuKeyValues(raw_ostream &OS, const FeatureMapTy &FeatureMap);
unsigned cpuNames(raw_ostream &OS);
Expand Down Expand Up @@ -141,7 +150,9 @@ class SubtargetEmitter : TargetFeaturesEmitter {
/// Emit some information about the SubtargetFeature as calls to a macro so
/// that they can be used from C++.
void SubtargetEmitter::emitSubtargetInfoMacroCalls(raw_ostream &OS) {
OS << "\n#ifdef GET_SUBTARGETINFO_MACRO\n";
// Undef the GET_SUBTARGETINFO_MACRO macro at the end of the scope since it's
// used within the scope.
IfDefEmitter IfDefMacro(OS, "GET_SUBTARGETINFO_MACRO", /*LateUndef=*/true);

std::vector<const Record *> FeatureList =
Records.getAllDerivedDefinitions("SubtargetFeature");
Expand All @@ -167,14 +178,6 @@ void SubtargetEmitter::emitSubtargetInfoMacroCalls(raw_ostream &OS) {
OS << "GET_SUBTARGETINFO_MACRO(" << FieldName << ", " << Default << ", "
<< Getter << ")\n";
}
OS << "#undef GET_SUBTARGETINFO_MACRO\n";
OS << "#endif // GET_SUBTARGETINFO_MACRO\n\n";

OS << "\n#ifdef GET_SUBTARGETINFO_MC_DESC\n";
OS << "#undef GET_SUBTARGETINFO_MC_DESC\n\n";

if (Target == "AArch64")
OS << "#include \"llvm/TargetParser/AArch64TargetParser.h\"\n\n";
}

//
Expand Down Expand Up @@ -440,26 +443,24 @@ void SubtargetEmitter::emitStageAndOperandCycleData(
continue;

StringRef Name = ProcModel.ItinsDef->getName();
OS << "\n// Functional units for \"" << Name << "\"\n"
<< "namespace " << Name << "FU {\n";

for (const auto &[Idx, FU] : enumerate(FUs))
OS << " const InstrStage::FuncUnits " << FU->getName() << " = 1ULL << "
<< Idx << ";\n";
{
OS << "\n// Functional units for \"" << Name << "\"\n";
NamespaceEmitter FUNamespace(OS, (Name + Twine("FU")).str());

OS << "} // end namespace " << Name << "FU\n";
for (const auto &[Idx, FU] : enumerate(FUs))
OS << " const InstrStage::FuncUnits " << FU->getName() << " = 1ULL << "
<< Idx << ";\n";
}

ConstRecVec BPs = ProcModel.ItinsDef->getValueAsListOfDefs("BP");
if (BPs.empty())
continue;
OS << "\n// Pipeline forwarding paths for itineraries \"" << Name << "\"\n"
<< "namespace " << Name << "Bypass {\n";
OS << "\n// Pipeline forwarding paths for itineraries \"" << Name << "\"\n";
NamespaceEmitter BypassNamespace(OS, (Name + Twine("Bypass")).str());

OS << " const unsigned NoBypass = 0;\n";
for (const auto &[Idx, BP] : enumerate(BPs))
OS << " const unsigned " << BP->getName() << " = 1 << " << Idx << ";\n";

OS << "} // end namespace " << Name << "Bypass\n";
}

// Begin stages table
Expand Down Expand Up @@ -1940,13 +1941,14 @@ void SubtargetEmitter::parseFeaturesFunction(raw_ostream &OS) {
}

void SubtargetEmitter::emitGenMCSubtargetInfo(raw_ostream &OS) {
OS << "namespace " << Target << "_MC {\n"
<< "unsigned resolveVariantSchedClassImpl(unsigned SchedClass,\n"
<< " const MCInst *MI, const MCInstrInfo *MCII, "
<< "const MCSubtargetInfo &STI, unsigned CPUID) {\n";
emitSchedModelHelpersImpl(OS, /* OnlyExpandMCPredicates */ true);
OS << "}\n";
OS << "} // end namespace " << Target << "_MC\n\n";
{
NamespaceEmitter NS(OS, (Target + Twine("_MC")).str());
OS << "unsigned resolveVariantSchedClassImpl(unsigned SchedClass,\n"
<< " const MCInst *MI, const MCInstrInfo *MCII, "
<< "const MCSubtargetInfo &STI, unsigned CPUID) {\n";
emitSchedModelHelpersImpl(OS, /* OnlyExpandMCPredicates */ true);
OS << "}\n";
}

OS << "struct " << Target
<< "GenMCSubtargetInfo : public MCSubtargetInfo {\n";
Expand Down Expand Up @@ -1982,46 +1984,37 @@ void SubtargetEmitter::emitGenMCSubtargetInfo(raw_ostream &OS) {
}

void SubtargetEmitter::emitMcInstrAnalysisPredicateFunctions(raw_ostream &OS) {
OS << "\n#ifdef GET_STIPREDICATE_DECLS_FOR_MC_ANALYSIS\n";
OS << "#undef GET_STIPREDICATE_DECLS_FOR_MC_ANALYSIS\n\n";

STIPredicateExpander PE(Target, /*Indent=*/0);
PE.setExpandForMC(true);
PE.setByRef(true);
for (const STIPredicateFunction &Fn : SchedModels.getSTIPredicates())
PE.expandSTIPredicate(OS, Fn);

OS << "#endif // GET_STIPREDICATE_DECLS_FOR_MC_ANALYSIS\n\n";

OS << "\n#ifdef GET_STIPREDICATE_DEFS_FOR_MC_ANALYSIS\n";
OS << "#undef GET_STIPREDICATE_DEFS_FOR_MC_ANALYSIS\n\n";
{
IfDefEmitter IfDefDecls(OS, "GET_STIPREDICATE_DECLS_FOR_MC_ANALYSIS");
PE.setExpandForMC(true);
PE.setByRef(true);
for (const STIPredicateFunction &Fn : SchedModels.getSTIPredicates())
PE.expandSTIPredicate(OS, Fn);
}

IfDefEmitter IfDefDefs(OS, "GET_STIPREDICATE_DEFS_FOR_MC_ANALYSIS");
std::string ClassPrefix = Target + "MCInstrAnalysis";
PE.setExpandDefinition(true);
PE.setClassPrefix(ClassPrefix);
for (const STIPredicateFunction &Fn : SchedModels.getSTIPredicates())
PE.expandSTIPredicate(OS, Fn);

OS << "#endif // GET_STIPREDICATE_DEFS_FOR_MC_ANALYSIS\n\n";
}

//
// SubtargetEmitter::run - Main subtarget enumeration emitter.
//
void SubtargetEmitter::run(raw_ostream &OS) {
emitSourceFileHeader("Subtarget Enumeration Source Fragment", OS);

OS << "\n#ifdef GET_SUBTARGETINFO_ENUM\n";
OS << "#undef GET_SUBTARGETINFO_ENUM\n\n";

OS << "namespace llvm {\n";
auto FeatureMap = enumeration(OS);
OS << "} // end namespace llvm\n\n";
OS << "#endif // GET_SUBTARGETINFO_ENUM\n\n";
FeatureMapTy SubtargetEmitter::emitEnums(raw_ostream &OS) {
IfDefEmitter IfDef(OS, "GET_SUBTARGETINFO_ENUM");
NamespaceEmitter NS(OS, "llvm");
return enumeration(OS);
}

emitSubtargetInfoMacroCalls(OS);
std::tuple<unsigned, unsigned, unsigned>
SubtargetEmitter::emitMCDesc(raw_ostream &OS, const FeatureMapTy &FeatureMap) {
IfDefEmitter IfDef(OS, "GET_SUBTARGETINFO_MC_DESC");
if (Target == "AArch64")
OS << "#include \"llvm/TargetParser/AArch64TargetParser.h\"\n\n";
NamespaceEmitter LlvmNS(OS, "llvm");

OS << "namespace llvm {\n";
unsigned NumFeatures = featureKeyValues(OS, FeatureMap);
OS << "\n";
emitSchedModel(OS);
Expand Down Expand Up @@ -2067,35 +2060,33 @@ void SubtargetEmitter::run(raw_ostream &OS) {
OS << "nullptr, nullptr, nullptr";
}
OS << ");\n}\n\n";
return {NumNames, NumFeatures, NumProcs};
}

OS << "} // end namespace llvm\n\n";

OS << "#endif // GET_SUBTARGETINFO_MC_DESC\n\n";

OS << "\n#ifdef GET_SUBTARGETINFO_TARGET_DESC\n";
OS << "#undef GET_SUBTARGETINFO_TARGET_DESC\n\n";
void SubtargetEmitter::emitTargetDesc(raw_ostream &OS) {
IfDefEmitter IfDef(OS, "GET_SUBTARGETINFO_TARGET_DESC");

OS << "#include \"llvm/ADT/BitmaskEnum.h\"\n";
OS << "#include \"llvm/Support/Debug.h\"\n";
OS << "#include \"llvm/Support/raw_ostream.h\"\n\n";
if (Target == "AArch64")
OS << "#include \"llvm/TargetParser/AArch64TargetParser.h\"\n\n";
parseFeaturesFunction(OS);
}

OS << "#endif // GET_SUBTARGETINFO_TARGET_DESC\n\n";

void SubtargetEmitter::emitHeader(raw_ostream &OS) {
// Create a TargetSubtargetInfo subclass to hide the MC layer initialization.
OS << "\n#ifdef GET_SUBTARGETINFO_HEADER\n";
OS << "#undef GET_SUBTARGETINFO_HEADER\n\n";
IfDefEmitter IfDef(OS, "GET_SUBTARGETINFO_HEADER");
NamespaceEmitter LLVMNS(OS, "llvm");

std::string ClassName = Target + "GenSubtargetInfo";
OS << "namespace llvm {\n";
OS << "class DFAPacketizer;\n";
OS << "namespace " << Target << "_MC {\n"
<< "unsigned resolveVariantSchedClassImpl(unsigned SchedClass,"
<< " const MCInst *MI, const MCInstrInfo *MCII, "
<< "const MCSubtargetInfo &STI, unsigned CPUID);\n"
<< "} // end namespace " << Target << "_MC\n\n";
{
NamespaceEmitter MCNS(OS, (Target + Twine("_MC")).str());
OS << "unsigned resolveVariantSchedClassImpl(unsigned SchedClass,"
<< " const MCInst *MI, const MCInstrInfo *MCII, "
<< "const MCSubtargetInfo &STI, unsigned CPUID);\n";
}
OS << "struct " << ClassName << " : public TargetSubtargetInfo {\n"
<< " explicit " << ClassName << "(const Triple &TT, StringRef CPU, "
<< "StringRef TuneCPU, StringRef FS);\n"
Expand Down Expand Up @@ -2140,17 +2131,15 @@ void SubtargetEmitter::run(raw_ostream &OS) {
PE.setByRef(false);
for (const STIPredicateFunction &Fn : SchedModels.getSTIPredicates())
PE.expandSTIPredicate(OS, Fn);
OS << "};\n";
}

OS << "};\n"
<< "} // end namespace llvm\n\n";

OS << "#endif // GET_SUBTARGETINFO_HEADER\n\n";

OS << "\n#ifdef GET_SUBTARGETINFO_CTOR\n";
OS << "#undef GET_SUBTARGETINFO_CTOR\n\n";

void SubtargetEmitter::emitCtor(raw_ostream &OS, unsigned NumNames,
unsigned NumFeatures, unsigned NumProcs) {
IfDefEmitter IfDef(OS, "GET_SUBTARGETINFO_CTOR");
OS << "#include \"llvm/CodeGen/TargetSchedule.h\"\n\n";
OS << "namespace llvm {\n";

NamespaceEmitter LLVMNS(OS, "llvm");
OS << "extern const llvm::StringRef " << Target << "Names[];\n";
OS << "extern const llvm::SubtargetFeatureKV " << Target << "FeatureKV[];\n";
OS << "extern const llvm::SubtargetSubTypeKV " << Target << "SubTypeKV[];\n";
Expand All @@ -2167,6 +2156,7 @@ void SubtargetEmitter::run(raw_ostream &OS) {
OS << "extern const unsigned " << Target << "ForwardingPaths[];\n";
}

std::string ClassName = Target + "GenSubtargetInfo";
OS << ClassName << "::" << ClassName << "(const Triple &TT, StringRef CPU, "
<< "StringRef TuneCPU, StringRef FS)\n";

Expand Down Expand Up @@ -2204,11 +2194,20 @@ void SubtargetEmitter::run(raw_ostream &OS) {
emitSchedModelHelpers(ClassName, OS);
emitHwModeCheck(ClassName, OS, /*IsMC=*/false);
emitGetMacroFusions(ClassName, OS);
}

OS << "} // end namespace llvm\n\n";

OS << "#endif // GET_SUBTARGETINFO_CTOR\n\n";
//
// SubtargetEmitter::run - Main subtarget enumeration emitter.
//
void SubtargetEmitter::run(raw_ostream &OS) {
emitSourceFileHeader("Subtarget Enumeration Source Fragment", OS);

auto FeatureMap = emitEnums(OS);
emitSubtargetInfoMacroCalls(OS);
auto [NumNames, NumFeatures, NumProcs] = emitMCDesc(OS, FeatureMap);
emitTargetDesc(OS);
emitHeader(OS);
emitCtor(OS, NumNames, NumFeatures, NumProcs);
emitMcInstrAnalysisPredicateFunctions(OS);
}

Expand Down