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/include/llvm/Support/Allocator.h b/include/llvm/Support/Allocator.h
index 527d4c6..f23a41f 100644
--- a/include/llvm/Support/Allocator.h
+++ b/include/llvm/Support/Allocator.h
@@ -23,6 +23,7 @@
   MallocAllocator() {}
   ~MallocAllocator() {}
   
+  void Reset() {}
   void *Allocate(unsigned Size, unsigned Alignment) { return malloc(Size); }
   void Deallocate(void *Ptr) { free(Ptr); }
   void PrintStats() const {}
@@ -38,6 +39,7 @@
   BumpPtrAllocator();
   ~BumpPtrAllocator();
   
+  void Reset();
   void *Allocate(unsigned Size, unsigned Alignment);
   void Deallocate(void *Ptr) {}
   void PrintStats() const;
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);