diff --git a/src/backend_x64/emit_x64.cpp b/src/backend_x64/emit_x64.cpp
index c8354778..f2afbc1a 100644
--- a/src/backend_x64/emit_x64.cpp
+++ b/src/backend_x64/emit_x64.cpp
@@ -51,6 +51,10 @@ static void EraseInstruction(IR::Block& block, IR::Inst* inst) {
     block.Instructions().erase(inst);
 }
 
+EmitX64::EmitX64(BlockOfCode* code, UserCallbacks cb, Jit* jit_interface)
+    : reg_alloc(code), code(code), cb(cb), jit_interface(jit_interface) {
+}
+
 EmitX64::BlockDescriptor EmitX64::Emit(IR::Block& block) {
     const IR::LocationDescriptor descriptor = block.Location();
 
@@ -95,6 +99,13 @@ EmitX64::BlockDescriptor EmitX64::Emit(IR::Block& block) {
     return basic_blocks[descriptor];
 }
 
+boost::optional<EmitX64::BlockDescriptor> EmitX64::GetBasicBlock(IR::LocationDescriptor descriptor) {
+    auto iter = basic_blocks.find(descriptor);
+    if (iter == basic_blocks.end())
+        return boost::none;
+    return boost::make_optional<BlockDescriptor>(iter->second);
+}
+
 void EmitX64::EmitBreakpoint(IR::Block&, IR::Inst*) {
     code->int3();
 }
diff --git a/src/backend_x64/emit_x64.h b/src/backend_x64/emit_x64.h
index 10ef7745..f4585a6d 100644
--- a/src/backend_x64/emit_x64.h
+++ b/src/backend_x64/emit_x64.h
@@ -33,14 +33,13 @@ class BlockOfCode;
 
 class EmitX64 final {
 public:
-    EmitX64(BlockOfCode* code, UserCallbacks cb, Jit* jit_interface)
-            : reg_alloc(code), code(code), cb(cb), jit_interface(jit_interface) {}
-
     struct BlockDescriptor {
         CodePtr code_ptr; ///< Entrypoint of emitted code
         size_t size;      ///< Length in bytes of emitted code
     };
 
+    EmitX64(BlockOfCode* code, UserCallbacks cb, Jit* jit_interface);
+
     /**
      * Emit host machine code for a basic block with intermediate representation `ir`.
      * @note ir is modified.
@@ -48,12 +47,7 @@ public:
     BlockDescriptor Emit(IR::Block& ir);
 
     /// Looks up an emitted host block in the cache.
-    boost::optional<BlockDescriptor> GetBasicBlock(IR::LocationDescriptor descriptor) {
-        auto iter = basic_blocks.find(descriptor);
-        if (iter == basic_blocks.end())
-            return boost::none;
-        return boost::make_optional<BlockDescriptor>(iter->second);
-    }
+    boost::optional<BlockDescriptor> GetBasicBlock(IR::LocationDescriptor descriptor);
 
     /// Empties the cache.
     void ClearCache();