move LiveDebugVariable constructors and destructors to after pImpl definition

Author: Kyle Krueger

llvm/lib/CodeGen/LiveDebugVariables.cpp

@@ -536,12 +536,6 @@ class UserLabel {
 
 namespace llvm {
 
-/// Implementation of the LiveDebugVariables pass.
-
-LiveDebugVariables::LiveDebugVariables() = default;
-LiveDebugVariables::~LiveDebugVariables() = default;
-LiveDebugVariables::LiveDebugVariables(LiveDebugVariables &&) = default;
-
 class LiveDebugVariables::LDVImpl {
   LocMap::Allocator allocator;
   MachineFunction *MF = nullptr;
@@ -683,6 +677,12 @@ class LiveDebugVariables::LDVImpl {
   void print(raw_ostream&);
 };
 
+/// Implementation of the LiveDebugVariables pass.
+
+LiveDebugVariables::LiveDebugVariables() = default;
+LiveDebugVariables::~LiveDebugVariables() = default;
+LiveDebugVariables::LiveDebugVariables(LiveDebugVariables &&) = default;
+
 } // namespace llvm
 
 static void printDebugLoc(const DebugLoc &DL, raw_ostream &CommentOS,