feat(relinker): lower BZHI and BEXTR under --to-rosetta

core/relinker/codegen/include/codegen/x86/BitfieldLowering.hpp

@@ -0,0 +1,29 @@
+#ifndef CODEGEN_X86_BITFIELDLOWERING_HPP
+#define CODEGEN_X86_BITFIELDLOWERING_HPP
+
+#include <codegen/x86/StubBodyBuilder.hpp>
+#include <optional>
+
+namespace Codegen {
+
+enum class BitfieldOperation : std::uint8_t {
+    ZeroHigh,
+    Extract,
+};
+
+struct BitfieldOperands {
+    BitfieldOperation Operation;
+    std::uint8_t Destination;
+    std::uint8_t Source;
+    std::uint8_t Control;
+    bool Wide;
+    std::optional<MemoryOperand> Memory;
+};
+
+[[nodiscard]] const char* BitfieldName(BitfieldOperation operation);
+[[nodiscard]] std::optional<BitfieldOperands> DecodeBitfield(const std::uint8_t* data, std::size_t length);
+void EmitBitfield(StubBodyBuilder& body, const BitfieldOperands& operands);
+
+}
+
+#endif