Add BumpPtrAllocator::getTotalMemory() to allow clients to query how much memory a BumpPtrAllocator allocated.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129727 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/Allocator.cpp b/lib/Support/Allocator.cpp
index 5e27df6..215b0f2 100644
--- a/lib/Support/Allocator.cpp
+++ b/lib/Support/Allocator.cpp
@@ -136,6 +136,14 @@
   return NumSlabs;
 }
 
+size_t BumpPtrAllocator::getTotalMemory() const {
+  size_t TotalMemory = 0;
+  for (MemSlab *Slab = CurSlab; Slab != 0; Slab = Slab->NextPtr) {
+    TotalMemory += Slab->Size;
+  }
+  return TotalMemory;
+}
+  
 void BumpPtrAllocator::PrintStats() const {
   unsigned NumSlabs = 0;
   size_t TotalMemory = 0;