Wdeprecated: Make BumpVectorContext movable

Turns out the one place that relied on the implicit copy ctor was safe
because it created an object in a state where the dtor was a no-op, but
that's more luck that good management.

Sure up the API by defining move construction and using it, which
implicitly disallows the unreliable copy operations.

llvm-svn: 244968

1 files changed, 7 insertions, 9 deletions

diff --git a/clang/lib/Analysis/CFG.cpp b/clang/lib/Analysis/CFG.cpp
index 3a358f91b09..efc93534ed1 100644
--- a/clang/lib/Analysis/CFG.cpp
+++ b/clang/lib/Analysis/CFG.cpp
@@ -176,8 +176,8 @@ private:
 
 public:
   /// Constructs empty scope linked to previous scope in specified place.
-  LocalScope(BumpVectorContext &ctx, const_iterator P)
-      : ctx(ctx), Vars(ctx, 4), Prev(P) {}
+  LocalScope(BumpVectorContext ctx, const_iterator P)
+      : ctx(std::move(ctx)), Vars(this->ctx, 4), Prev(P) {}
 
   /// Begin of scope in direction of CFG building (backwards).
   const_iterator begin() const { return const_iterator(*this, Vars.size()); }
@@ -1247,13 +1247,11 @@ void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) {
 /// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either
 /// way return valid LocalScope object.
 LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) {
-  if (!Scope) {
-    llvm::BumpPtrAllocator &alloc = cfg->getAllocator();
-    Scope = alloc.Allocate<LocalScope>();
-    BumpVectorContext ctx(alloc);
-    new (Scope) LocalScope(ctx, ScopePos);
-  }
-  return Scope;
+  if (Scope)
+    return Scope;
+  llvm::BumpPtrAllocator &alloc = cfg->getAllocator();
+  return new (alloc.Allocate<LocalScope>())
+      LocalScope(BumpVectorContext(alloc), ScopePos);
 }
 
 /// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement