[SILGen] NFC: Moved EndBorrowCleanup to header.

Previously the declaration and definition of EndBorrowCleanup were both
within SILGenExpr.cpp.  That prevented the usage of cleanups which end
borrow scopes within other files.  Here, the declaration is moved to
Cleanup.h.  The necessary changes are made to SILGenExpr.cpp to keep the
definition of member functions in place.

Author: nate-chandler

lib/SILGen/Cleanup.h

@@ -133,6 +133,14 @@ class LLVM_LIBRARY_VISIBILITY Cleanup {
   }
 };
 
+struct EndBorrowCleanup final : Cleanup {
+  SILValue borrowedValue;
+  EndBorrowCleanup(SILValue borrowedValue);
+  void emit(SILGenFunction &SGF, CleanupLocation l,
+            ForUnwind_t forUnwind) override;
+  void dump(SILGenFunction &) const override;
+};
+
 /// A cleanup depth is generally used to denote the set of cleanups
 /// between the given cleanup (and not including it) and the top of
 /// the stack.

lib/SILGen/SILGenExpr.cpp

@@ -158,34 +158,30 @@ SILGenFunction::emitManagedBeginBorrow(SILLocation loc, SILValue v,
   return emitManagedBorrowedRValueWithCleanup(v, bbi, lowering);
 }
 
-namespace {
-
-struct EndBorrowCleanup : Cleanup {
-  SILValue borrowedValue;
-
-  EndBorrowCleanup(SILValue borrowedValue) : borrowedValue(borrowedValue) {
-    if (auto *arg = dyn_cast<SILPhiArgument>(borrowedValue)) {
-      if (auto *ti = arg->getSingleTerminator()) {
-        assert(!ti->isTransformationTerminator() &&
-               "Transforming terminators do not have end_borrow");
-      }
+EndBorrowCleanup::EndBorrowCleanup(SILValue borrowedValue)
+    : borrowedValue(borrowedValue) {
+  if (auto *arg = dyn_cast<SILPhiArgument>(borrowedValue)) {
+    if (auto *ti = arg->getSingleTerminator()) {
+      assert(!ti->isTransformationTerminator() &&
+             "Transforming terminators do not have end_borrow");
     }
   }
+}
 
-  void emit(SILGenFunction &SGF, CleanupLocation l,
-            ForUnwind_t forUnwind) override {
-    SGF.B.createEndBorrow(l, borrowedValue);
-  }
+void EndBorrowCleanup::emit(SILGenFunction &SGF, CleanupLocation l,
+                            ForUnwind_t forUnwind) {
+  SGF.B.createEndBorrow(l, borrowedValue);
+}
 
-  void dump(SILGenFunction &) const override {
+void EndBorrowCleanup::dump(SILGenFunction &) const {
 #ifndef NDEBUG
-    llvm::errs() << "EndBorrowCleanup "
-                 << "State:" << getState() << "\n"
-                 << "borrowed:" << borrowedValue
-                 << "\n";
+  llvm::errs() << "EndBorrowCleanup "
+               << "State:" << getState() << "\n"
+               << "borrowed:" << borrowedValue << "\n";
 #endif
-  }
-};
+}
+
+namespace {
 
 struct FormalEvaluationEndBorrowCleanup : Cleanup {
   FormalEvaluationContext::stable_iterator Depth;