2 files changed, 123 insertions, 0 deletions
diff --git a/backend/lib/CodeGen/CMakeLists.txt b/backend/lib/CodeGen/CMakeLists.txt
index 3a45cec..2c4f6f8 100644
--- a/backend/lib/CodeGen/CMakeLists.txt
+++ b/backend/lib/CodeGen/CMakeLists.txt
@@ -2,6 +2,7 @@
 
 set(
   RCCBackendCodeGenSources
+  CompilationUnit.cpp
   InstructionDescriptor.cpp
   LowLevelType.cpp
   MachineCompilationStatus.cpp
@@ -29,6 +30,7 @@ set(
 )
 set(
   RCCBackendCodeGenHeaders
+  "${RCC_BACKEND_SOURCE_DIR}/include/rcc/CodeGen/CompilationUnit.h"
   "${RCC_BACKEND_SOURCE_DIR}/include/rcc/CodeGen/InstructionDescriptor.h"
   "${RCC_BACKEND_SOURCE_DIR}/include/rcc/CodeGen/LowLevelType.h"
   "${RCC_BACKEND_SOURCE_DIR}/include/rcc/CodeGen/MachineCompilationStatus.h"
@@ -85,6 +87,7 @@ install(
 )
 
 rcc_backend_register_format_files(
+  "${CMAKE_CURRENT_SOURCE_DIR}/CompilationUnit.cpp"
   "${CMAKE_CURRENT_SOURCE_DIR}/InstructionDescriptor.cpp"
   "${CMAKE_CURRENT_SOURCE_DIR}/LowLevelType.cpp"
   "${CMAKE_CURRENT_SOURCE_DIR}/MachineCompilationStatus.cpp"
@@ -112,6 +115,7 @@ rcc_backend_register_format_files(
   ${RCCBackendCodeGenHeaders}
 )
 rcc_backend_register_tidy_files(
+  "${CMAKE_CURRENT_SOURCE_DIR}/CompilationUnit.cpp"
   "${CMAKE_CURRENT_SOURCE_DIR}/InstructionDescriptor.cpp"
   "${CMAKE_CURRENT_SOURCE_DIR}/LowLevelType.cpp"
   "${CMAKE_CURRENT_SOURCE_DIR}/MachineCompilationStatus.cpp"
diff --git a/backend/lib/CodeGen/CompilationUnit.cpp b/backend/lib/CodeGen/CompilationUnit.cpp
new file mode 100644
index 0000000..1de6487
--- /dev/null
+++ b/backend/lib/CodeGen/CompilationUnit.cpp
@@ -0,0 +1,119 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "rcc/CodeGen/CompilationUnit.h"
+
+#include "rcc/CodeGen/MachineFunction.h"
+
+#include <cstddef>
+#include <memory>
+#include <string>
+#include <string_view>
+#include <unordered_set>
+#include <utility>
+
+namespace rcc {
+
+CompilationUnit::CompilationUnit() = default;
+
+CompilationUnit::CompilationUnit(CompilationUnit &&) noexcept = default;
+
+CompilationUnit &CompilationUnit::operator=(CompilationUnit &&) noexcept = default;
+
+CompilationUnit::~CompilationUnit() = default;
+
+Expected<MachineFunction *> CompilationUnit::createMachineFunction(std::string Name) {
+  if (Name.empty())
+    return makeUnexpected(ErrorCode::InvalidArgument, "machine function name cannot be empty");
+  if (FunctionNameToIndex.contains(Name)) {
+    return makeUnexpected(ErrorCode::InvalidArgument,
+                          "machine function name is already present in the compilation unit");
+  }
+
+  auto StableID = FunctionIDGenerator.allocate();
+  if (!StableID)
+    return std::unexpected(StableID.error());
+  auto Function = MachineFunction::create(std::move(Name), *StableID);
+  if (!Function)
+    return std::unexpected(Function.error());
+
+  MachineFunction *Result = Function->get();
+  const std::size_t Index = Functions.size();
+  FunctionNameToIndex.emplace(std::string(Result->name()), Index);
+  Functions.push_back(std::move(*Function));
+  return Result;
+}
+
+MachineFunction *CompilationUnit::functionAt(std::size_t Index) noexcept {
+  if (Index >= Functions.size())
+    return nullptr;
+  return Functions[Index].get();
+}
+
+const MachineFunction *CompilationUnit::functionAt(std::size_t Index) const noexcept {
+  if (Index >= Functions.size())
+    return nullptr;
+  return Functions[Index].get();
+}
+
+MachineFunction *CompilationUnit::function(std::string_view Name) noexcept {
+  const auto Position = FunctionNameToIndex.find(Name);
+  if (Position == FunctionNameToIndex.end())
+    return nullptr;
+  return Functions[Position->second].get();
+}
+
+const MachineFunction *CompilationUnit::function(std::string_view Name) const noexcept {
+  const auto Position = FunctionNameToIndex.find(Name);
+  if (Position == FunctionNameToIndex.end())
+    return nullptr;
+  return Functions[Position->second].get();
+}
+
+MachineFunction *CompilationUnit::function(MachineFunctionStableID ID) noexcept {
+  for (const std::unique_ptr<MachineFunction> &Function : Functions) {
+    if (Function->stableID() == ID)
+      return Function.get();
+  }
+  return nullptr;
+}
+
+const MachineFunction *CompilationUnit::function(MachineFunctionStableID ID) const noexcept {
+  for (const std::unique_ptr<MachineFunction> &Function : Functions) {
+    if (Function->stableID() == ID)
+      return Function.get();
+  }
+  return nullptr;
+}
+
+Expected<void> CompilationUnit::verify() const {
+  if (FunctionNameToIndex.size() != Functions.size()) {
+    return makeUnexpected(ErrorCode::VerificationError,
+                          "compilation unit function name index has an inconsistent size");
+  }
+
+  std::unordered_set<MachineFunctionStableID> StableIDs;
+  for (std::size_t Index = 0; Index < Functions.size(); ++Index) {
+    const std::unique_ptr<MachineFunction> &Function = Functions[Index];
+    if (Function == nullptr) {
+      return makeUnexpected(ErrorCode::VerificationError,
+                            "compilation unit contains a null machine function");
+    }
+    if (Function->name().empty() || !Function->stableID().isValid()) {
+      return makeUnexpected(ErrorCode::VerificationError,
+                            "compilation unit contains an invalid machine function identity");
+    }
+    if (!StableIDs.insert(Function->stableID()).second) {
+      return makeUnexpected(ErrorCode::VerificationError,
+                            "compilation unit contains duplicate machine function StableIDs");
+    }
+
+    const auto Position = FunctionNameToIndex.find(Function->name());
+    if (Position == FunctionNameToIndex.end() || Position->second != Index) {
+      return makeUnexpected(ErrorCode::VerificationError,
+                            "compilation unit function name index is inconsistent");
+    }
+  }
+  return {};
+}
+
+} // namespace rcc