[CodeGen] Add target machine registry

1 files changed, 73 insertions, 0 deletions

diff --git a/backend/lib/MC/TargetRegistry.cpp b/backend/lib/MC/TargetRegistry.cpp
new file mode 100644
index 0000000..217f59b
--- /dev/null
+++ b/backend/lib/MC/TargetRegistry.cpp
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "rcc/MC/TargetRegistry.h"
+
+#include "rcc/Target/TargetMachine.h"
+
+#include <algorithm>
+#include <string>
+#include <utility>
+#include <vector>
+
+namespace rcc {
+namespace {
+
+[[nodiscard]] std::vector<const Target *> &registeredTargets() {
+  static std::vector<const Target *> Targets;
+  return Targets;
+}
+
+} // namespace
+
+TargetMachineOptions Target::defaultMachineOptions() const {
+  return DefaultOptions();
+}
+
+Expected<std::unique_ptr<TargetMachine>>
+Target::createTargetMachine(TargetMachineOptions Options) const {
+  return TargetMachineCtor(*this, std::move(Options));
+}
+
+void TargetRegistry::registerTarget(const Target &RegisteredTarget) {
+  std::vector<const Target *> &Targets = registeredTargets();
+  if (std::ranges::find(Targets, &RegisteredTarget) == Targets.end())
+    Targets.push_back(&RegisteredTarget);
+}
+
+Expected<const Target *> TargetRegistry::lookupTarget(std::string_view Triple) {
+  const Target *Best = nullptr;
+  unsigned BestQuality = 0;
+  for (const Target *Candidate : registeredTargets()) {
+    const unsigned Quality = Candidate->matchQuality(Triple);
+    if (Quality > BestQuality) {
+      Best = Candidate;
+      BestQuality = Quality;
+    } else if (Quality != 0 && Quality == BestQuality) {
+      return makeUnexpected(ErrorCode::InvalidInvocation,
+                            "target triple matches multiple registered targets");
+    }
+  }
+  if (Best == nullptr) {
+    return makeUnexpected(ErrorCode::Unsupported,
+                          "no registered target supports triple '" + std::string(Triple) + "'");
+  }
+  return Best;
+}
+
+Expected<const Target *> TargetRegistry::defaultTarget() {
+  const Target *Default = nullptr;
+  for (const Target *Candidate : registeredTargets()) {
+    if (!Candidate->isDefault())
+      continue;
+    if (Default != nullptr) {
+      return makeUnexpected(ErrorCode::InternalError,
+                            "multiple targets are registered as the default target");
+    }
+    Default = Candidate;
+  }
+  if (Default == nullptr)
+    return makeUnexpected(ErrorCode::InternalError, "no default target is registered");
+  return Default;
+}
+
+} // namespace rcc