diff options
Diffstat (limited to 'backend/lib/AsmPrinter/AsmPrinter.cpp')
| -rw-r--r-- | backend/lib/AsmPrinter/AsmPrinter.cpp | 679 |
1 files changed, 679 insertions, 0 deletions
diff --git a/backend/lib/AsmPrinter/AsmPrinter.cpp b/backend/lib/AsmPrinter/AsmPrinter.cpp new file mode 100644 index 0000000..cebd6b8 --- /dev/null +++ b/backend/lib/AsmPrinter/AsmPrinter.cpp @@ -0,0 +1,679 @@ +// SPDX-License-Identifier: GPL-3.0-or-later + +#include "rcc/CodeGen/AsmPrinter.h" + +#include "rcc/CodeGen/CompilationUnit.h" +#include "rcc/CodeGen/GenericConstant.h" +#include "rcc/CodeGen/GenericOpcodes.h" +#include "rcc/CodeGen/GlobalObject.h" +#include "rcc/CodeGen/InstructionDescriptor.h" +#include "rcc/CodeGen/MachineBasicBlock.h" +#include "rcc/CodeGen/MachineCFIInfo.h" +#include "rcc/CodeGen/MachineConstantPool.h" +#include "rcc/CodeGen/MachineFunction.h" +#include "rcc/CodeGen/MachineInstr.h" +#include "rcc/CodeGen/MachineJumpTableInfo.h" +#include "rcc/CodeGen/MachineMCContext.h" +#include "rcc/CodeGen/MachineOperand.h" +#include "rcc/CodeGen/MachineVerifier.h" +#include "rcc/CodeGen/TargetConstant.h" +#include "rcc/CodeGen/TargetDescription.h" +#include "rcc/CodeGen/TargetMCInstLowering.h" +#include "rcc/MC/MCCFI.h" +#include "rcc/MC/MCContext.h" +#include "rcc/MC/MCExpr.h" +#include "rcc/MC/MCSection.h" +#include "rcc/MC/MCStreamer.h" +#include "rcc/MC/MCSymbol.h" + +#include <cstddef> +#include <cstdint> +#include <string> +#include <utility> +#include <variant> + +namespace rcc { +namespace { + +[[nodiscard]] Expected<mc::MCExprRef> symbolExpression(mc::MCSymbolRef Symbol) { + auto Expression = mc::MCExpr::symbol(std::move(Symbol)); + if (!Expression) + return std::unexpected(Expression.error()); + return *Expression; +} + +[[nodiscard]] Expected<mc::MCExprRef> addConstant(mc::MCExprRef Expression, std::int64_t Addend) { + if (Addend == 0) + return Expression; + auto Result = mc::MCExpr::binary(mc::MCBinaryOperator::Add, std::move(Expression), + mc::MCExpr::constant(Addend)); + if (!Result) + return std::unexpected(Result.error()); + return *Result; +} + +[[nodiscard]] Expected<mc::MCExprRef> +symbolDifference(mc::MCSymbolRef Minuend, mc::MCSymbolRef Subtrahend, std::int64_t Addend) { + auto Left = symbolExpression(std::move(Minuend)); + if (!Left) + return std::unexpected(Left.error()); + auto Right = symbolExpression(std::move(Subtrahend)); + if (!Right) + return std::unexpected(Right.error()); + auto Difference = + mc::MCExpr::binary(mc::MCBinaryOperator::Subtract, std::move(*Left), std::move(*Right)); + if (!Difference) + return std::unexpected(Difference.error()); + return addConstant(std::move(*Difference), Addend); +} + +[[nodiscard]] Expected<mc::MCCFIInstruction> +lowerCFIInstruction(const MachineCFIInstruction &Instruction, MachineMCContext &Context) { + mc::MCCFIInstruction Result; + const auto Register = [&Result](const MachineCFIRegisterRule &Rule) { + Result.Operands.push_back(static_cast<std::int64_t>(Rule.Register.value())); + }; + const auto Offset = [&Result](const MachineCFIOffsetRule &Rule) { + Result.Operands.push_back(Rule.Offset); + }; + const auto RegisterOffset = [&Result](const MachineCFIRegisterOffsetRule &Rule) { + Result.Operands.push_back(static_cast<std::int64_t>(Rule.Register.value())); + Result.Operands.push_back(Rule.Offset); + }; + + switch (Instruction.operation()) { + case MachineCFIOperation::SameValue: + Result.Operation = mc::MCCFIOperation::SameValue; + Register(*Instruction.getIf<MachineCFIRegisterRule>()); + break; + case MachineCFIOperation::RememberState: + Result.Operation = mc::MCCFIOperation::RememberState; + break; + case MachineCFIOperation::RestoreState: + Result.Operation = mc::MCCFIOperation::RestoreState; + break; + case MachineCFIOperation::Offset: + Result.Operation = mc::MCCFIOperation::Offset; + RegisterOffset(*Instruction.getIf<MachineCFIRegisterOffsetRule>()); + break; + case MachineCFIOperation::DefCFARegister: + Result.Operation = mc::MCCFIOperation::DefCFARegister; + Register(*Instruction.getIf<MachineCFIRegisterRule>()); + break; + case MachineCFIOperation::DefCFAOffset: + Result.Operation = mc::MCCFIOperation::DefCFAOffset; + Offset(*Instruction.getIf<MachineCFIOffsetRule>()); + break; + case MachineCFIOperation::DefCFA: + Result.Operation = mc::MCCFIOperation::DefCFA; + RegisterOffset(*Instruction.getIf<MachineCFIRegisterOffsetRule>()); + break; + case MachineCFIOperation::RelativeOffset: + Result.Operation = mc::MCCFIOperation::RelativeOffset; + RegisterOffset(*Instruction.getIf<MachineCFIRegisterOffsetRule>()); + break; + case MachineCFIOperation::AdjustCFAOffset: + Result.Operation = mc::MCCFIOperation::AdjustCFAOffset; + Offset(*Instruction.getIf<MachineCFIOffsetRule>()); + break; + case MachineCFIOperation::Escape: + Result.Operation = mc::MCCFIOperation::Escape; + Result.Bytes = Instruction.getIf<MachineCFIEscapeRule>()->Bytes; + break; + case MachineCFIOperation::Restore: + Result.Operation = mc::MCCFIOperation::Restore; + Register(*Instruction.getIf<MachineCFIRegisterRule>()); + break; + case MachineCFIOperation::Undefined: + Result.Operation = mc::MCCFIOperation::Undefined; + Register(*Instruction.getIf<MachineCFIRegisterRule>()); + break; + case MachineCFIOperation::Register: { + Result.Operation = mc::MCCFIOperation::Register; + const auto &Rule = *Instruction.getIf<MachineCFIRegisterRegisterRule>(); + Result.Operands.push_back(static_cast<std::int64_t>(Rule.Register.value())); + Result.Operands.push_back(static_cast<std::int64_t>(Rule.SourceRegister.value())); + break; + } + case MachineCFIOperation::WindowSave: + Result.Operation = mc::MCCFIOperation::WindowSave; + break; + case MachineCFIOperation::NegateReturnAddressState: + Result.Operation = mc::MCCFIOperation::NegateReturnAddressState; + break; + case MachineCFIOperation::NegateReturnAddressStateWithPC: + Result.Operation = mc::MCCFIOperation::NegateReturnAddressStateWithPC; + break; + case MachineCFIOperation::GNUArgsSize: + Result.Operation = mc::MCCFIOperation::GNUArgsSize; + Offset(*Instruction.getIf<MachineCFIOffsetRule>()); + break; + case MachineCFIOperation::Label: { + Result.Operation = mc::MCCFIOperation::Label; + auto Symbol = Context.symbol(Instruction.getIf<MachineCFILabelRule>()->Symbol, + mc::MCSymbolKind::Temporary); + if (!Symbol) + return std::unexpected(Symbol.error()); + Result.Symbol = std::move(*Symbol); + break; + } + case MachineCFIOperation::ValueOffset: + Result.Operation = mc::MCCFIOperation::ValueOffset; + RegisterOffset(*Instruction.getIf<MachineCFIRegisterOffsetRule>()); + break; + case MachineCFIOperation::LLVMDefAddressSpaceCFA: + case MachineCFIOperation::LLVMRegisterPair: + case MachineCFIOperation::LLVMVectorRegisters: + case MachineCFIOperation::LLVMVectorOffset: + case MachineCFIOperation::LLVMVectorRegisterMask: + return makeUnexpected(ErrorCode::Unsupported, + "assembly emission does not support this LLVM-specific CFI operation"); + case MachineCFIOperation::Count: + return makeUnexpected(ErrorCode::AssemblyLoweringFailed, + "machine CFI instruction has an invalid operation"); + } + + auto Verification = Result.verify(); + if (!Verification) + return std::unexpected(Verification.error()); + return Result; +} + +[[nodiscard]] Expected<void> emitNamedLabel(const MachineOperand &Operand, + MachineMCContext &Context, mc::MCStreamer &Streamer) { + const auto *SymbolOperand = Operand.getIf<MCSymbolOperand>(); + if (SymbolOperand == nullptr || SymbolOperand->Offset != 0 || Operand.targetFlags() != 0) { + return makeUnexpected(ErrorCode::AssemblyLoweringFailed, + "label pseudo requires an unmodified MC symbol operand"); + } + auto Symbol = Context.symbol(SymbolOperand->Name, mc::MCSymbolKind::Temporary); + if (!Symbol) + return std::unexpected(Symbol.error()); + return Streamer.emitLabel(std::move(*Symbol)); +} + +[[nodiscard]] bool validValueSize(std::uint64_t Size) noexcept { + return Size == 1 || Size == 2 || Size == 4 || Size == 8; +} + +[[nodiscard]] Expected<void> emitGlobalAttributes(const GlobalObjectDesc &Object, + const mc::MCSymbolRef &Symbol, + mc::MCStreamer &Streamer) { + switch (Object.Linkage) { + case GlobalLinkage::External: + case GlobalLinkage::Appending: + case GlobalLinkage::Common: { + auto Emitted = Streamer.emitSymbolAttribute(Symbol, mc::MCSymbolAttribute::Global); + if (!Emitted) + return std::unexpected(Emitted.error()); + break; + } + case GlobalLinkage::LinkOnceAny: + case GlobalLinkage::LinkOnceODR: + case GlobalLinkage::WeakAny: + case GlobalLinkage::WeakODR: + case GlobalLinkage::ExternalWeak: { + auto Emitted = Streamer.emitSymbolAttribute(Symbol, mc::MCSymbolAttribute::Weak); + if (!Emitted) + return std::unexpected(Emitted.error()); + break; + } + case GlobalLinkage::Internal: + case GlobalLinkage::Private: { + auto Emitted = Streamer.emitSymbolAttribute(Symbol, mc::MCSymbolAttribute::Local); + if (!Emitted) + return std::unexpected(Emitted.error()); + break; + } + case GlobalLinkage::AvailableExternally: + break; + case GlobalLinkage::Count: + return makeUnexpected(ErrorCode::AssemblyLoweringFailed, + "global object has invalid linkage during assembly emission"); + } + + if (Object.Visibility == GlobalVisibility::Hidden) { + auto Emitted = Streamer.emitSymbolAttribute(Symbol, mc::MCSymbolAttribute::Hidden); + if (!Emitted) + return std::unexpected(Emitted.error()); + } else if (Object.Visibility == GlobalVisibility::Protected) { + auto Emitted = Streamer.emitSymbolAttribute(Symbol, mc::MCSymbolAttribute::Protected); + if (!Emitted) + return std::unexpected(Emitted.error()); + } + return Streamer.emitSymbolAttribute(Symbol, Object.TLSModel == GlobalTLSModel::None + ? mc::MCSymbolAttribute::Object + : mc::MCSymbolAttribute::TLSObject); +} + +} // namespace + +Expected<void> AsmPrinter::verifyFunction(const MachineFunction &Function) const { + const MachineFunctionProperties Required = { + MachineFunctionProperty::NoPHIs, + MachineFunctionProperty::Legalized, + MachineFunctionProperty::RegBankSelected, + MachineFunctionProperty::Selected, + MachineFunctionProperty::TiedOpsRewritten, + MachineFunctionProperty::NoVRegs, + MachineFunctionProperty::FrameFinalized, + MachineFunctionProperty::NoFrameIndices, + MachineFunctionProperty::NoExecutablePseudos, + }; + if (!Function.properties().containsAll(Required)) { + const MachineFunctionProperties Missing = Required.missingFrom(Function.properties()); + return makeUnexpected(ErrorCode::AssemblyLoweringFailed, + "assembly emission requires finalized MIR properties: " + + Missing.toString()); + } + if (!Options.VerifyInput) + return {}; + return MachineVerifier::verify(Function, *Target, + MachineVerifierOptions{.Mode = MachineVerifierMode::Generic, + .Stage = PipelineStage::Emission, + .VerifyProperties = true}); +} + +Expected<void> AsmPrinter::emitCompilationUnit(const CompilationUnit &Unit) { + if (UnitEmissionStarted) { + return makeUnexpected(ErrorCode::AssemblyLoweringFailed, + "a compilation unit can only be emitted once by an AsmPrinter"); + } + UnitEmissionStarted = true; + + auto Initialized = Context->initialize(Unit); + if (!Initialized) + return std::unexpected(Initialized.error()); + auto Header = Lowering->emitFileHeader(*Context, *Streamer); + if (!Header) + return std::unexpected(Header.error()); + + auto Globals = emitGlobalObjects(Unit); + if (!Globals) + return std::unexpected(Globals.error()); + + for (std::size_t Index = 0; Index < Unit.functionCount(); ++Index) { + const MachineFunction *Function = Unit.functionAt(Index); + if (Function == nullptr) { + return makeUnexpected(ErrorCode::InternalError, + "compilation unit contains a null function during assembly emission"); + } + auto Emitted = emitFunction(*Function); + if (!Emitted) + return std::unexpected(Emitted.error()); + } + + auto Trailer = Lowering->emitFileTrailer(*Context, *Streamer); + if (!Trailer) + return std::unexpected(Trailer.error()); + auto Finished = Streamer->finish(); + if (!Finished) + return std::unexpected(Finished.error()); + UnitEmissionFinished = true; + return {}; +} + +Expected<void> AsmPrinter::emitGlobalObjects(const CompilationUnit &Unit) { + for (std::size_t Index = 0; Index < Unit.globalObjectCount(); ++Index) { + const GlobalObjectDesc *Object = Unit.globalObjectAt(Index); + if (Object == nullptr) + return makeUnexpected(ErrorCode::InternalError, "compilation unit contains a null global"); + if (Object->isDeclaration() || Object->Linkage == GlobalLinkage::AvailableExternally) + continue; + + const mc::MCSymbolRef Symbol = Context->globalSymbol(*Object); + if (!Symbol) + return makeUnexpected(ErrorCode::InternalError, "global object has no MC symbol"); + auto Attributes = emitGlobalAttributes(*Object, Symbol, *Streamer); + if (!Attributes) + return std::unexpected(Attributes.error()); + + if (Object->Linkage == GlobalLinkage::Common) { + auto Name = mc::printMCSymbolName(Symbol->name()); + if (!Name) + return std::unexpected(Name.error()); + auto Common = + Streamer->emitDirective("comm", *Name + "," + std::to_string(Object->Size) + "," + + std::to_string(Object->Align.bytes())); + if (!Common) + return std::unexpected(Common.error()); + continue; + } + + auto Description = Lowering->globalSection(*Object, *Context); + if (!Description) + return std::unexpected(Description.error()); + auto Section = Context->context().getOrCreateSection(std::move(*Description)); + if (!Section) + return std::unexpected(Section.error()); + auto Switched = Streamer->switchSection(std::move(*Section)); + if (!Switched) + return std::unexpected(Switched.error()); + auto Aligned = Streamer->emitAlignment(Object->Align.bytes()); + if (!Aligned) + return std::unexpected(Aligned.error()); + auto Label = Streamer->emitLabel(Symbol); + if (!Label) + return std::unexpected(Label.error()); + if (!Object->Initializer) { + return makeUnexpected(ErrorCode::AssemblyLoweringFailed, + "defined global object has no initializer"); + } + auto Initializer = Lowering->emitGlobalInitializer(*Object->Initializer, *Context, *Streamer); + if (!Initializer) + return std::unexpected(Initializer.error()); + auto Size = Streamer->emitSymbolSize( + Symbol, mc::MCExpr::constant(static_cast<std::int64_t>(Object->Size))); + if (!Size) + return std::unexpected(Size.error()); + } + return {}; +} + +Expected<void> AsmPrinter::emitFunction(const MachineFunction &Function) { + if (UnitEmissionFinished) { + return makeUnexpected(ErrorCode::AssemblyLoweringFailed, + "cannot emit a function after the assembly stream is finalized"); + } + auto Verification = verifyFunction(Function); + if (!Verification) + return std::unexpected(Verification.error()); + auto Initialized = Context->initializeFunction(Function); + if (!Initialized) + return std::unexpected(Initialized.error()); + + auto SectionDescription = Lowering->textSection(Function); + if (!SectionDescription) + return std::unexpected(SectionDescription.error()); + auto Section = Context->context().getOrCreateSection(std::move(*SectionDescription)); + if (!Section) + return std::unexpected(Section.error()); + auto Switched = Streamer->switchSection(std::move(*Section)); + if (!Switched) + return std::unexpected(Switched.error()); + + const mc::MCSymbolRef FunctionSymbol = Context->functionSymbol(Function); + if (!FunctionSymbol) { + return makeUnexpected(ErrorCode::InternalError, + "function has no MC symbol after context initialization"); + } + if (Options.EmitFunctionDirectives) { + auto Global = Streamer->emitSymbolAttribute(FunctionSymbol, mc::MCSymbolAttribute::Global); + if (!Global) + return std::unexpected(Global.error()); + auto Type = Streamer->emitSymbolAttribute(FunctionSymbol, mc::MCSymbolAttribute::Function); + if (!Type) + return std::unexpected(Type.error()); + } + if (const auto Alignment = Function.attributes().alignment()) { + auto Aligned = Streamer->emitAlignment(Alignment->bytes()); + if (!Aligned) + return std::unexpected(Aligned.error()); + } + auto FunctionLabel = Streamer->emitLabel(FunctionSymbol); + if (!FunctionLabel) + return std::unexpected(FunctionLabel.error()); + if (Options.EmitCFI) { + mc::MCCFIInstruction StartProc; + StartProc.Operation = mc::MCCFIOperation::StartProc; + auto CFIStart = Streamer->emitCFI(StartProc); + if (!CFIStart) + return std::unexpected(CFIStart.error()); + } + + auto Body = emitFunctionBody(Function); + if (!Body) + return std::unexpected(Body.error()); + if (Options.EmitCFI) { + mc::MCCFIInstruction EndProc; + EndProc.Operation = mc::MCCFIOperation::EndProc; + auto CFIEnd = Streamer->emitCFI(EndProc); + if (!CFIEnd) + return std::unexpected(CFIEnd.error()); + } + + auto EndSymbol = Context->symbol(".Lfunc_end" + std::to_string(Function.stableID().value()), + mc::MCSymbolKind::Temporary); + if (!EndSymbol) + return std::unexpected(EndSymbol.error()); + auto EndLabel = Streamer->emitLabel(*EndSymbol); + if (!EndLabel) + return std::unexpected(EndLabel.error()); + if (Options.EmitFunctionDirectives) { + auto Size = symbolDifference(*EndSymbol, FunctionSymbol, 0); + if (!Size) + return std::unexpected(Size.error()); + auto EmittedSize = Streamer->emitSymbolSize(FunctionSymbol, std::move(*Size)); + if (!EmittedSize) + return std::unexpected(EmittedSize.error()); + } + + auto Constants = emitConstantPool(Function); + if (!Constants) + return std::unexpected(Constants.error()); + return emitJumpTables(Function); +} + +Expected<void> AsmPrinter::emitFunctionBody(const MachineFunction &Function) { + for (const MachineBasicBlock *Block = Function.firstBlock(); Block != nullptr; + Block = Block->next()) { + if (Block->attributes().alignment().bytes() > 1) { + auto Aligned = Streamer->emitAlignment(Block->attributes().alignment().bytes()); + if (!Aligned) + return std::unexpected(Aligned.error()); + } + if (Options.EmitBlockLabels) { + const mc::MCSymbolRef Symbol = Context->blockSymbol(*Block); + if (!Symbol) + return makeUnexpected(ErrorCode::InternalError, "machine block has no MC symbol"); + auto Label = Streamer->emitLabel(Symbol); + if (!Label) + return std::unexpected(Label.error()); + } + + for (const MachineInstr *Instruction = Block->firstInstruction(); Instruction != nullptr; + Instruction = Instruction->next()) { + const InstructionDescriptor *Descriptor = + Target->instructionDescriptor(Instruction->opcode()); + if (Descriptor == nullptr) { + return makeUnexpected(ErrorCode::AssemblyLoweringFailed, + "assembly emission encountered an unknown opcode"); + } + if (Options.EmitInstructionSymbols) { + if (const auto SymbolName = Instruction->preInstrSymbol()) { + auto Symbol = Context->symbol(std::string(*SymbolName), mc::MCSymbolKind::Temporary); + if (!Symbol) + return std::unexpected(Symbol.error()); + auto Label = Streamer->emitLabel(std::move(*Symbol)); + if (!Label) + return std::unexpected(Label.error()); + } + } + + Expected<void> Emitted; + if (Instruction->opcode() == opcode(GenericOpcode::CFI_INSTRUCTION)) { + const auto *Index = Instruction->operandAt(0) == nullptr + ? nullptr + : Instruction->operandAt(0)->getIf<CFIIndexOperand>(); + const MachineCFIInstruction *CFI = + Index == nullptr ? nullptr : Function.cfiInfo().instruction(Index->Index); + if (CFI == nullptr) { + return makeUnexpected(ErrorCode::AssemblyLoweringFailed, + "CFI pseudo references an invalid CFI instruction"); + } + if (Options.EmitCFI) { + auto Lowered = lowerCFIInstruction(*CFI, *Context); + if (!Lowered) + return std::unexpected(Lowered.error()); + Emitted = Streamer->emitCFI(*Lowered); + } + } else if (Instruction->opcode() == opcode(GenericOpcode::EH_LABEL) || + Instruction->opcode() == opcode(GenericOpcode::GC_LABEL) || + Instruction->opcode() == opcode(GenericOpcode::ANNOTATION_LABEL)) { + if (Instruction->operandAt(0) == nullptr) { + return makeUnexpected(ErrorCode::AssemblyLoweringFailed, + "label pseudo has no symbol operand"); + } + Emitted = emitNamedLabel(*Instruction->operandAt(0), *Context, *Streamer); + } else if (Descriptor->Flags.has(InstructionFlag::TerminalEmission)) { + Emitted = Lowering->emitTerminalInstruction(*Instruction, *Context, *Streamer); + } else if (Descriptor->Flags.has(InstructionFlag::Meta)) { + Emitted = {}; + } else if (Descriptor->Flags.has(InstructionFlag::ProducesCode)) { + auto Lowered = Lowering->lowerInstruction(*Instruction, *Context); + if (!Lowered) + return std::unexpected(Lowered.error()); + Emitted = Streamer->emitInstruction(*Lowered); + } else { + return makeUnexpected(ErrorCode::AssemblyLoweringFailed, + "non-meta instruction has no assembly emission behavior"); + } + if (!Emitted) + return std::unexpected(Emitted.error()); + + if (Options.EmitInstructionSymbols) { + if (const auto SymbolName = Instruction->postInstrSymbol()) { + auto Symbol = Context->symbol(std::string(*SymbolName), mc::MCSymbolKind::Temporary); + if (!Symbol) + return std::unexpected(Symbol.error()); + auto Label = Streamer->emitLabel(std::move(*Symbol)); + if (!Label) + return std::unexpected(Label.error()); + } + } + } + } + return {}; +} + +Expected<void> AsmPrinter::emitConstantPool(const MachineFunction &Function) { + for (const MachineConstantPoolEntry &Entry : Function.constantPool().entries()) { + const MachineConstantPoolEntryDesc *Description = Entry.description(); + if (Description == nullptr) + continue; + auto SectionDescription = Lowering->constantPoolSection(Function, Entry); + if (!SectionDescription) + return std::unexpected(SectionDescription.error()); + auto Section = Context->context().getOrCreateSection(std::move(*SectionDescription)); + if (!Section) + return std::unexpected(Section.error()); + auto Switched = Streamer->switchSection(std::move(*Section)); + if (!Switched) + return std::unexpected(Switched.error()); + auto Aligned = Streamer->emitAlignment(Description->Align.bytes()); + if (!Aligned) + return std::unexpected(Aligned.error()); + + const mc::MCSymbolRef Symbol = Context->constantPoolSymbol(Function, Entry.index()); + if (!Symbol) + return makeUnexpected(ErrorCode::InternalError, "constant-pool entry has no MC symbol"); + auto Label = Streamer->emitLabel(Symbol); + if (!Label) + return std::unexpected(Label.error()); + + Expected<void> Emitted; + if (const auto *Generic = std::get_if<GenericConstantData>(&Description->Value)) { + Emitted = Lowering->emitGenericConstant(*Generic, Description->Size, *Context, *Streamer); + } else if (const auto *TargetValue = std::get_if<TargetConstant>(&Description->Value)) { + Emitted = Lowering->emitTargetConstant(*TargetValue, *Context, *Streamer); + } else if (const auto *Difference = + std::get_if<SymbolDifferenceConstant>(&Description->Value)) { + if (!validValueSize(Description->Size)) { + return makeUnexpected(ErrorCode::AssemblyLoweringFailed, + "symbol-difference constant has an unsupported storage size"); + } + auto Minuend = Context->symbol(Difference->Minuend); + if (!Minuend) + return std::unexpected(Minuend.error()); + auto Subtrahend = Context->symbol(Difference->Subtrahend); + if (!Subtrahend) + return std::unexpected(Subtrahend.error()); + auto Expression = symbolDifference(*Minuend, *Subtrahend, Difference->Addend); + if (!Expression) + return std::unexpected(Expression.error()); + Emitted = + Streamer->emitValue(std::move(*Expression), static_cast<std::uint8_t>(Description->Size)); + } else if (const auto *Address = std::get_if<BlockAddressConstant>(&Description->Value)) { + if (!validValueSize(Description->Size)) { + return makeUnexpected(ErrorCode::AssemblyLoweringFailed, + "block-address constant has an unsupported storage size"); + } + auto AddressSymbol = Context->blockAddressSymbol(Address->FunctionName, Address->BlockName); + if (!AddressSymbol) + return std::unexpected(AddressSymbol.error()); + auto Expression = symbolExpression(std::move(*AddressSymbol)); + if (!Expression) + return std::unexpected(Expression.error()); + Expression = addConstant(std::move(*Expression), Address->Addend); + if (!Expression) + return std::unexpected(Expression.error()); + Emitted = + Streamer->emitValue(std::move(*Expression), static_cast<std::uint8_t>(Description->Size)); + } else if (const auto *TargetExpression = + std::get_if<TargetExpressionConstant>(&Description->Value)) { + Emitted = Lowering->emitTargetConstant(TargetExpression->Expression, *Context, *Streamer); + } else { + return makeUnexpected(ErrorCode::InternalError, "constant-pool value has an invalid kind"); + } + if (!Emitted) + return std::unexpected(Emitted.error()); + } + return {}; +} + +Expected<void> AsmPrinter::emitJumpTables(const MachineFunction &Function) { + for (const MachineJumpTableEntry &Entry : Function.jumpTableInfo().tables()) { + const MachineJumpTableDesc *Description = Entry.description(); + if (Description == nullptr) + continue; + auto SectionDescription = Lowering->jumpTableSection(Function, Entry); + if (!SectionDescription) + return std::unexpected(SectionDescription.error()); + auto Section = Context->context().getOrCreateSection(std::move(*SectionDescription)); + if (!Section) + return std::unexpected(Section.error()); + auto Switched = Streamer->switchSection(std::move(*Section)); + if (!Switched) + return std::unexpected(Switched.error()); + auto Aligned = Streamer->emitAlignment(Description->Align.bytes()); + if (!Aligned) + return std::unexpected(Aligned.error()); + + const mc::MCSymbolRef TableSymbol = Context->jumpTableSymbol(Function, Entry.index()); + if (!TableSymbol) + return makeUnexpected(ErrorCode::InternalError, "jump-table entry has no MC symbol"); + auto Label = Streamer->emitLabel(TableSymbol); + if (!Label) + return std::unexpected(Label.error()); + + if (Description->Encoding != JumpTableEntryEncoding::BlockAddress && + Description->Encoding != JumpTableEntryEncoding::LabelDifference32 && + Description->Encoding != JumpTableEntryEncoding::LabelDifference64) { + auto TargetTable = Lowering->emitTargetJumpTable(Function, Entry, *Context, *Streamer); + if (!TargetTable) + return std::unexpected(TargetTable.error()); + continue; + } + + for (const MachineBasicBlock *TargetBlock : Description->Targets) { + if (TargetBlock == nullptr) + return makeUnexpected(ErrorCode::AssemblyLoweringFailed, "jump table has a null target"); + const mc::MCSymbolRef TargetSymbol = Context->blockSymbol(*TargetBlock); + if (!TargetSymbol) + return makeUnexpected(ErrorCode::InternalError, "jump-table target has no MC symbol"); + + Expected<mc::MCExprRef> Expression = symbolExpression(TargetSymbol); + if (Description->Encoding == JumpTableEntryEncoding::LabelDifference32 || + Description->Encoding == JumpTableEntryEncoding::LabelDifference64) + Expression = symbolDifference(TargetSymbol, TableSymbol, 0); + if (!Expression) + return std::unexpected(Expression.error()); + auto Value = Streamer->emitValue(std::move(*Expression), Description->EntrySize); + if (!Value) + return std::unexpected(Value.error()); + } + } + return {}; +} + +} // namespace rcc |