Added Reset() to free all allocated memory regions and reset state to be the same as right after ctor.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41728 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/Allocator.cpp b/lib/Support/Allocator.cpp
index 234fd41..e68c3e2 100644
--- a/lib/Support/Allocator.cpp
+++ b/lib/Support/Allocator.cpp
@@ -92,6 +92,12 @@
   ((MemRegion*)TheMemory)->Deallocate();
 }
 
+void BumpPtrAllocator::Reset() {
+  ((MemRegion*)TheMemory)->Deallocate();
+  TheMemory = malloc(4096);
+  ((MemRegion*)TheMemory)->Init(4096, 1, 0);
+}
+
 void *BumpPtrAllocator::Allocate(unsigned Size, unsigned Align) {
   MemRegion *MRP = (MemRegion*)TheMemory;
   void *Ptr = MRP->Allocate(Size, Align, &MRP);