8 files changed, 668 insertions, 0 deletions

diff --git a/backend/include/rcc/MC/MCCFI.h b/backend/include/rcc/MC/MCCFI.h
new file mode 100644
index 0000000..e6ac396
--- /dev/null
+++ b/backend/include/rcc/MC/MCCFI.h
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#ifndef RCC_MC_MCCFI_H
+#define RCC_MC_MCCFI_H
+
+#include "rcc/MC/MCSymbol.h"
+#include "rcc/Support/Error.h"
+
+#include <cstdint>
+#include <vector>
+
+namespace rcc::mc {
+
+enum class MCCFIOperation : std::uint8_t {
+  StartProc,
+  EndProc,
+  Sections,
+  Personality,
+  LSDA,
+  SignalFrame,
+  ReturnColumn,
+  SameValue,
+  RememberState,
+  RestoreState,
+  Offset,
+  DefCFARegister,
+  DefCFAOffset,
+  DefCFA,
+  RelativeOffset,
+  AdjustCFAOffset,
+  Escape,
+  Restore,
+  Undefined,
+  Register,
+  WindowSave,
+  NegateReturnAddressState,
+  NegateReturnAddressStateWithPC,
+  GNUArgsSize,
+  Label,
+  ValueOffset,
+};
+
+struct MCCFIInstruction final {
+  MCCFIOperation Operation = MCCFIOperation::StartProc;
+  std::vector<std::int64_t> Operands;
+  std::vector<std::uint8_t> Bytes;
+  MCSymbolRef Symbol;
+
+  [[nodiscard]] Expected<void> verify() const;
+};
+
+} // namespace rcc::mc
+
+#endif // RCC_MC_MCCFI_H
diff --git a/backend/include/rcc/MC/MCContext.h b/backend/include/rcc/MC/MCContext.h
new file mode 100644
index 0000000..e9b2d90
--- /dev/null
+++ b/backend/include/rcc/MC/MCContext.h
@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#ifndef RCC_MC_MCCONTEXT_H
+#define RCC_MC_MCCONTEXT_H
+
+#include "rcc/MC/MCSection.h"
+#include "rcc/MC/MCSymbol.h"
+#include "rcc/Support/Error.h"
+
+#include <cstdint>
+#include <functional>
+#include <string>
+#include <string_view>
+#include <unordered_map>
+
+namespace rcc::mc {
+
+class MCContext final {
+public:
+  [[nodiscard]] Expected<MCSymbolRef> getOrCreateSymbol(std::string Name, MCSymbolKind Kind);
+  [[nodiscard]] Expected<MCSymbolRef> createTemporarySymbol(std::string_view Prefix);
+  [[nodiscard]] MCSymbolRef symbol(std::string_view Name) const noexcept;
+
+  [[nodiscard]] Expected<MCSectionRef> getOrCreateSection(MCSectionDesc Description);
+  [[nodiscard]] MCSectionRef section(std::string_view Name) const noexcept;
+
+private:
+  struct StringHash final {
+    using is_transparent = void; // NOLINT(readability-identifier-naming)
+
+    [[nodiscard]] std::size_t operator()(std::string_view Value) const noexcept {
+      return std::hash<std::string_view>{}(Value);
+    }
+  };
+
+  std::unordered_map<std::string, MCSymbolRef, StringHash, std::equal_to<>> Symbols;
+  std::unordered_map<std::string, MCSectionRef, StringHash, std::equal_to<>> Sections;
+  std::uint64_t NextTemporarySymbol = 0;
+};
+
+} // namespace rcc::mc
+
+#endif // RCC_MC_MCCONTEXT_H
diff --git a/backend/include/rcc/MC/MCExpr.h b/backend/include/rcc/MC/MCExpr.h
new file mode 100644
index 0000000..15ff6fd
--- /dev/null
+++ b/backend/include/rcc/MC/MCExpr.h
@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#ifndef RCC_MC_MCEXPR_H
+#define RCC_MC_MCEXPR_H
+
+#include "rcc/MC/MCSymbol.h"
+#include "rcc/Support/Error.h"
+
+#include <cstddef>
+#include <cstdint>
+#include <memory>
+#include <optional>
+#include <variant>
+
+namespace rcc::mc {
+
+class MCExpr;
+using MCExprRef = std::shared_ptr<const MCExpr>;
+
+enum class MCUnaryOperator : std::uint8_t {
+  Plus,
+  Minus,
+  BitwiseNot,
+  LogicalNot,
+};
+
+enum class MCBinaryOperator : std::uint8_t {
+  Add,
+  Subtract,
+  Multiply,
+  Divide,
+  Modulo,
+  ShiftLeft,
+  ShiftRight,
+  BitwiseAnd,
+  BitwiseOr,
+  BitwiseXor,
+  LogicalAnd,
+  LogicalOr,
+  Equal,
+  NotEqual,
+  Less,
+  LessEqual,
+  Greater,
+  GreaterEqual,
+};
+
+struct MCSymbolRefExpr final {
+  MCSymbolRef Symbol;
+};
+
+struct MCUnaryExpr final {
+  MCUnaryOperator Operator = MCUnaryOperator::Plus;
+  MCExprRef Operand;
+};
+
+struct MCBinaryExpr final {
+  MCBinaryOperator Operator = MCBinaryOperator::Add;
+  MCExprRef Left;
+  MCExprRef Right;
+};
+
+struct MCTargetExpr final {
+  std::uint32_t Kind = 0;
+  MCExprRef Operand;
+};
+
+class MCExpr final {
+public:
+  enum class Kind : std::uint8_t {
+    Constant,
+    SymbolRef,
+    Unary,
+    Binary,
+    Target,
+  };
+
+  [[nodiscard]] static MCExprRef constant(std::int64_t Value);
+  [[nodiscard]] static Expected<MCExprRef> symbol(MCSymbolRef Symbol);
+  [[nodiscard]] static Expected<MCExprRef> unary(MCUnaryOperator Operator, MCExprRef Operand);
+  [[nodiscard]] static Expected<MCExprRef> binary(MCBinaryOperator Operator, MCExprRef Left,
+                                                  MCExprRef Right);
+  [[nodiscard]] static Expected<MCExprRef> target(std::uint32_t Kind, MCExprRef Operand);
+
+  [[nodiscard]] Kind kind() const noexcept {
+    return ExpressionKind;
+  }
+
+  template <typename ValueT> [[nodiscard]] const ValueT *getIf() const noexcept {
+    return std::get_if<ValueT>(&Storage);
+  }
+
+  [[nodiscard]] Expected<void> verify(std::size_t MaximumDepth = 256) const;
+  [[nodiscard]] std::optional<std::int64_t> evaluateAbsolute() const noexcept;
+
+private:
+  using StorageT =
+      std::variant<std::int64_t, MCSymbolRefExpr, MCUnaryExpr, MCBinaryExpr, MCTargetExpr>;
+
+  MCExpr(Kind ExpressionKind, StorageT Storage)
+      : ExpressionKind(ExpressionKind), Storage(std::move(Storage)) {}
+
+  Kind ExpressionKind;
+  StorageT Storage;
+};
+
+} // namespace rcc::mc
+
+#endif // RCC_MC_MCEXPR_H
diff --git a/backend/include/rcc/MC/MCInst.h b/backend/include/rcc/MC/MCInst.h
new file mode 100644
index 0000000..c6da93b
--- /dev/null
+++ b/backend/include/rcc/MC/MCInst.h
@@ -0,0 +1,174 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#ifndef RCC_MC_MCINST_H
+#define RCC_MC_MCINST_H
+
+#include "rcc/MC/MCExpr.h"
+
+#include <cstddef>
+#include <cstdint>
+#include <span>
+#include <utility>
+#include <variant>
+#include <vector>
+
+namespace rcc::mc {
+
+class MCRegister final {
+public:
+  constexpr MCRegister() noexcept = default;
+
+  [[nodiscard]] static constexpr MCRegister fromValue(std::uint32_t Value) noexcept {
+    return MCRegister(Value);
+  }
+
+  [[nodiscard]] constexpr std::uint32_t value() const noexcept {
+    return Value;
+  }
+
+  [[nodiscard]] constexpr bool isValid() const noexcept {
+    return Value != 0;
+  }
+
+  friend constexpr bool operator==(MCRegister Left, MCRegister Right) noexcept = default;
+
+private:
+  explicit constexpr MCRegister(std::uint32_t Value) noexcept : Value(Value) {}
+
+  std::uint32_t Value = 0;
+};
+
+class MCOpcode final {
+public:
+  constexpr MCOpcode() noexcept = default;
+
+  [[nodiscard]] static constexpr MCOpcode fromValue(std::uint32_t Value) noexcept {
+    return MCOpcode(Value);
+  }
+
+  [[nodiscard]] constexpr std::uint32_t value() const noexcept {
+    return Value;
+  }
+
+  [[nodiscard]] constexpr bool isValid() const noexcept {
+    return Value != 0;
+  }
+
+  friend constexpr bool operator==(MCOpcode Left, MCOpcode Right) noexcept = default;
+
+private:
+  explicit constexpr MCOpcode(std::uint32_t Value) noexcept : Value(Value) {}
+
+  std::uint32_t Value = 0;
+};
+
+class MCOperand final {
+public:
+  enum class Kind : std::uint8_t {
+    Register,
+    Immediate,
+    Float32Bits,
+    Float64Bits,
+    Expression,
+  };
+
+  [[nodiscard]] static MCOperand registerOperand(MCRegister Register) noexcept {
+    return MCOperand(Kind::Register, Register);
+  }
+
+  [[nodiscard]] static MCOperand immediate(std::int64_t Value) noexcept {
+    return MCOperand(Kind::Immediate, Value);
+  }
+
+  [[nodiscard]] static MCOperand float32Bits(std::uint32_t Value) noexcept {
+    return MCOperand(Kind::Float32Bits, Value);
+  }
+
+  [[nodiscard]] static MCOperand float64Bits(std::uint64_t Value) noexcept {
+    return MCOperand(Kind::Float64Bits, Value);
+  }
+
+  [[nodiscard]] static MCOperand expression(MCExprRef Value) {
+    return MCOperand(Kind::Expression, std::move(Value));
+  }
+
+  [[nodiscard]] Kind kind() const noexcept {
+    return OperandKind;
+  }
+
+  [[nodiscard]] const MCRegister *registerValue() const noexcept {
+    return std::get_if<MCRegister>(&Storage);
+  }
+
+  [[nodiscard]] const std::int64_t *immediateValue() const noexcept {
+    return std::get_if<std::int64_t>(&Storage);
+  }
+
+  [[nodiscard]] const std::uint32_t *float32BitsValue() const noexcept {
+    return std::get_if<std::uint32_t>(&Storage);
+  }
+
+  [[nodiscard]] const std::uint64_t *float64BitsValue() const noexcept {
+    return std::get_if<std::uint64_t>(&Storage);
+  }
+
+  [[nodiscard]] const MCExprRef *expressionValue() const noexcept {
+    return std::get_if<MCExprRef>(&Storage);
+  }
+
+private:
+  using StorageT = std::variant<MCRegister, std::int64_t, std::uint32_t, std::uint64_t, MCExprRef>;
+
+  MCOperand(Kind OperandKind, StorageT Storage)
+      : OperandKind(OperandKind), Storage(std::move(Storage)) {}
+
+  Kind OperandKind;
+  StorageT Storage;
+};
+
+class MCInst final {
+public:
+  explicit MCInst(MCOpcode InstructionOpcode) : InstructionOpcode(InstructionOpcode) {}
+
+  [[nodiscard]] MCOpcode opcode() const noexcept {
+    return InstructionOpcode;
+  }
+
+  void setFlags(std::uint32_t NewFlags) noexcept {
+    Flags = NewFlags;
+  }
+
+  [[nodiscard]] std::uint32_t flags() const noexcept {
+    return Flags;
+  }
+
+  void setSourceIdentity(std::uint64_t Identity) noexcept {
+    SourceIdentity = Identity;
+  }
+
+  [[nodiscard]] std::uint64_t sourceIdentity() const noexcept {
+    return SourceIdentity;
+  }
+
+  void reserveOperands(std::size_t Count) {
+    Operands.reserve(Count);
+  }
+
+  void addOperand(MCOperand Operand) {
+    Operands.push_back(std::move(Operand));
+  }
+
+  [[nodiscard]] std::span<const MCOperand> operands() const noexcept {
+    return Operands;
+  }
+
+private:
+  MCOpcode InstructionOpcode;
+  std::uint32_t Flags = 0;
+  std::uint64_t SourceIdentity = 0;
+  std::vector<MCOperand> Operands;
+};
+
+} // namespace rcc::mc
+
+#endif // RCC_MC_MCINST_H
diff --git a/backend/include/rcc/MC/MCInstPrinter.h b/backend/include/rcc/MC/MCInstPrinter.h
new file mode 100644
index 0000000..6024ced
--- /dev/null
+++ b/backend/include/rcc/MC/MCInstPrinter.h
@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#ifndef RCC_MC_MCINSTPRINTER_H
+#define RCC_MC_MCINSTPRINTER_H
+
+#include "rcc/MC/MCInst.h"
+#include "rcc/Support/Error.h"
+
+#include <cstdint>
+#include <string>
+#include <string_view>
+
+namespace rcc::mc {
+
+class MCInstPrinter {
+public:
+  virtual ~MCInstPrinter() = default;
+
+  [[nodiscard]] virtual Expected<std::string> printInstruction(const MCInst &Instruction) const = 0;
+
+  [[nodiscard]] virtual Expected<std::string>
+  printTargetExpression(std::uint32_t Kind, std::string_view Operand) const = 0;
+};
+
+[[nodiscard]] Expected<std::string> printMCExpression(const MCExpr &Expression,
+                                                      const MCInstPrinter &Printer);
+[[nodiscard]] Expected<std::string> printMCSymbolName(std::string_view Name);
+
+} // namespace rcc::mc
+
+#endif // RCC_MC_MCINSTPRINTER_H
diff --git a/backend/include/rcc/MC/MCSection.h b/backend/include/rcc/MC/MCSection.h
new file mode 100644
index 0000000..4f76427
--- /dev/null
+++ b/backend/include/rcc/MC/MCSection.h
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#ifndef RCC_MC_MCSECTION_H
+#define RCC_MC_MCSECTION_H
+
+#include "rcc/MC/MCSymbol.h"
+#include "rcc/Support/Error.h"
+
+#include <cstdint>
+#include <initializer_list>
+#include <memory>
+#include <optional>
+#include <string>
+#include <string_view>
+
+namespace rcc::mc {
+
+enum class MCSectionKind : std::uint8_t {
+  Text,
+  ReadOnly,
+  Data,
+  BSS,
+  TLSData,
+  TLSBSS,
+  EHFrame,
+  Custom,
+};
+
+enum class MCSectionFlag : std::uint8_t {
+  Alloc,
+  Executable,
+  Writable,
+  Merge,
+  Strings,
+  TLS,
+  Group,
+  Retain,
+  Count,
+};
+
+class MCSectionFlags final {
+public:
+  constexpr MCSectionFlags() noexcept = default;
+
+  constexpr MCSectionFlags(std::initializer_list<MCSectionFlag> Flags) noexcept {
+    for (const MCSectionFlag Flag : Flags)
+      set(Flag);
+  }
+
+  constexpr void set(MCSectionFlag Flag) noexcept {
+    const auto Index = static_cast<std::uint8_t>(Flag);
+    if (Index < static_cast<std::uint8_t>(MCSectionFlag::Count))
+      Mask |= std::uint16_t{1} << Index;
+  }
+
+  [[nodiscard]] constexpr bool has(MCSectionFlag Flag) const noexcept {
+    const auto Index = static_cast<std::uint8_t>(Flag);
+    return Index < static_cast<std::uint8_t>(MCSectionFlag::Count) &&
+           (Mask & (std::uint16_t{1} << Index)) != 0;
+  }
+
+  [[nodiscard]] constexpr std::uint16_t rawValue() const noexcept {
+    return Mask;
+  }
+
+  friend constexpr bool operator==(MCSectionFlags Left, MCSectionFlags Right) noexcept = default;
+
+private:
+  std::uint16_t Mask = 0;
+};
+
+struct MCSectionDesc final {
+  std::string Name;
+  MCSectionKind Kind = MCSectionKind::Custom;
+  MCSectionFlags Flags;
+  std::uint64_t Alignment = 1;
+  std::uint64_t EntrySize = 0;
+  MCSymbolRef Group;
+  std::optional<std::uint64_t> UniqueID;
+
+  [[nodiscard]] Expected<void> verify() const;
+
+  friend bool operator==(const MCSectionDesc &Left, const MCSectionDesc &Right) = default;
+};
+
+class MCSection final {
+public:
+  [[nodiscard]] std::string_view name() const noexcept {
+    return Description.Name;
+  }
+
+  [[nodiscard]] const MCSectionDesc &description() const noexcept {
+    return Description;
+  }
+
+private:
+  explicit MCSection(MCSectionDesc Description) : Description(std::move(Description)) {}
+
+  MCSectionDesc Description;
+
+  friend class MCContext;
+};
+
+using MCSectionRef = std::shared_ptr<const MCSection>;
+
+} // namespace rcc::mc
+
+#endif // RCC_MC_MCSECTION_H
diff --git a/backend/include/rcc/MC/MCStreamer.h b/backend/include/rcc/MC/MCStreamer.h
new file mode 100644
index 0000000..3add976
--- /dev/null
+++ b/backend/include/rcc/MC/MCStreamer.h
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#ifndef RCC_MC_MCSTREAMER_H
+#define RCC_MC_MCSTREAMER_H
+
+#include "rcc/MC/MCCFI.h"
+#include "rcc/MC/MCInst.h"
+#include "rcc/MC/MCInstPrinter.h"
+#include "rcc/MC/MCSection.h"
+#include "rcc/MC/MCSymbol.h"
+#include "rcc/Support/Error.h"
+
+#include <cstdint>
+#include <span>
+#include <string>
+#include <string_view>
+#include <unordered_set>
+
+namespace rcc::mc {
+
+enum class MCSymbolAttribute : std::uint8_t {
+  Global,
+  Weak,
+  Local,
+  Hidden,
+  Protected,
+  Function,
+  Object,
+  TLSObject,
+};
+
+class MCStreamer {
+public:
+  virtual ~MCStreamer() = default;
+
+  [[nodiscard]] virtual Expected<void> switchSection(MCSectionRef Section) = 0;
+  [[nodiscard]] virtual Expected<void> emitLabel(MCSymbolRef Symbol) = 0;
+  [[nodiscard]] virtual Expected<void> emitInstruction(const MCInst &Instruction) = 0;
+  [[nodiscard]] virtual Expected<void> emitValue(MCExprRef Value, std::uint8_t Size) = 0;
+  [[nodiscard]] virtual Expected<void> emitBytes(std::span<const std::uint8_t> Bytes) = 0;
+  [[nodiscard]] virtual Expected<void> emitZeroFill(std::uint64_t Size) = 0;
+  [[nodiscard]] virtual Expected<void> emitAlignment(std::uint64_t Alignment, std::uint8_t Fill = 0,
+                                                     std::uint64_t MaximumBytes = 0) = 0;
+  [[nodiscard]] virtual Expected<void> emitSymbolAttribute(MCSymbolRef Symbol,
+                                                           MCSymbolAttribute Attribute) = 0;
+  [[nodiscard]] virtual Expected<void> emitSymbolSize(MCSymbolRef Symbol, MCExprRef Size) = 0;
+  [[nodiscard]] virtual Expected<void> emitDirective(std::string_view Name,
+                                                     std::string_view Arguments = {}) = 0;
+  [[nodiscard]] virtual Expected<void> emitCFI(const MCCFIInstruction &Instruction) = 0;
+  [[nodiscard]] virtual Expected<void> emitInlineAssembly(std::string_view Text) = 0;
+  [[nodiscard]] virtual Expected<void> emitComment(std::string_view Text) = 0;
+  [[nodiscard]] virtual Expected<void> finish() = 0;
+};
+
+class AsmTextStreamer final : public MCStreamer {
+public:
+  explicit AsmTextStreamer(const MCInstPrinter &Printer) noexcept : Printer(&Printer) {}
+
+  [[nodiscard]] Expected<void> switchSection(MCSectionRef Section) override;
+  [[nodiscard]] Expected<void> emitLabel(MCSymbolRef Symbol) override;
+  [[nodiscard]] Expected<void> emitInstruction(const MCInst &Instruction) override;
+  [[nodiscard]] Expected<void> emitValue(MCExprRef Value, std::uint8_t Size) override;
+  [[nodiscard]] Expected<void> emitBytes(std::span<const std::uint8_t> Bytes) override;
+  [[nodiscard]] Expected<void> emitZeroFill(std::uint64_t Size) override;
+  [[nodiscard]] Expected<void> emitAlignment(std::uint64_t Alignment, std::uint8_t Fill = 0,
+                                             std::uint64_t MaximumBytes = 0) override;
+  [[nodiscard]] Expected<void> emitSymbolAttribute(MCSymbolRef Symbol,
+                                                   MCSymbolAttribute Attribute) override;
+  [[nodiscard]] Expected<void> emitSymbolSize(MCSymbolRef Symbol, MCExprRef Size) override;
+  [[nodiscard]] Expected<void> emitDirective(std::string_view Name,
+                                             std::string_view Arguments = {}) override;
+  [[nodiscard]] Expected<void> emitCFI(const MCCFIInstruction &Instruction) override;
+  [[nodiscard]] Expected<void> emitInlineAssembly(std::string_view Text) override;
+  [[nodiscard]] Expected<void> emitComment(std::string_view Text) override;
+  [[nodiscard]] Expected<void> finish() override;
+
+  [[nodiscard]] Expected<std::string> takeOutput();
+
+private:
+  [[nodiscard]] Expected<void> appendLine(std::string_view Prefix, std::string_view Text);
+  [[nodiscard]] Expected<void> requireActiveSection() const;
+
+  const MCInstPrinter *Printer;
+  MCSectionRef CurrentSection;
+  std::unordered_set<std::string> DefinedSymbols;
+  std::string Output;
+  bool IsFinished = false;
+  bool OutputWasTaken = false;
+};
+
+} // namespace rcc::mc
+
+#endif // RCC_MC_MCSTREAMER_H
diff --git a/backend/include/rcc/MC/MCSymbol.h b/backend/include/rcc/MC/MCSymbol.h
new file mode 100644
index 0000000..1b7b878
--- /dev/null
+++ b/backend/include/rcc/MC/MCSymbol.h
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#ifndef RCC_MC_MCSYMBOL_H
+#define RCC_MC_MCSYMBOL_H
+
+#include <cstdint>
+#include <memory>
+#include <string>
+#include <string_view>
+
+namespace rcc::mc {
+
+class MCContext;
+
+enum class MCSymbolKind : std::uint8_t {
+  Generic,
+  Function,
+  Object,
+  BasicBlock,
+  ConstantPool,
+  JumpTable,
+  LiteralIsland,
+  Section,
+  Temporary,
+};
+
+class MCSymbol final {
+public:
+  [[nodiscard]] std::string_view name() const noexcept {
+    return Name;
+  }
+
+  [[nodiscard]] MCSymbolKind kind() const noexcept {
+    return Kind;
+  }
+
+  [[nodiscard]] bool isTemporary() const noexcept {
+    return Kind == MCSymbolKind::Temporary || Kind == MCSymbolKind::BasicBlock ||
+           Kind == MCSymbolKind::ConstantPool || Kind == MCSymbolKind::JumpTable ||
+           Kind == MCSymbolKind::LiteralIsland;
+  }
+
+private:
+  MCSymbol(std::string Name, MCSymbolKind Kind) : Name(std::move(Name)), Kind(Kind) {}
+
+  std::string Name;
+  MCSymbolKind Kind;
+
+  friend class MCContext;
+};
+
+using MCSymbolRef = std::shared_ptr<const MCSymbol>;
+
+} // namespace rcc::mc
+
+#endif // RCC_MC_MCSYMBOL_H