Enhance clang_getCXTUResourceUsage() to report the sizes of the memory buffers used by PCH.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@130460 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Serialization/ChainedIncludesSource.cpp b/lib/Serialization/ChainedIncludesSource.cpp
index 4b95419..da5be95 100644
--- a/lib/Serialization/ChainedIncludesSource.cpp
+++ b/lib/Serialization/ChainedIncludesSource.cpp
@@ -208,6 +208,16 @@
 void ChainedIncludesSource::PrintStats() {
   return getFinalReader().PrintStats();
 }
+void ChainedIncludesSource::getMemoryBufferSizes(MemoryBufferSizes &sizes)const{
+  for (unsigned i = 0, e = CIs.size(); i != e; ++i) {
+    if (const ExternalASTSource *eSrc =
+        CIs[i]->getASTContext().getExternalSource()) {
+      eSrc->getMemoryBufferSizes(sizes);
+    }
+  }
+
+  getFinalReader().getMemoryBufferSizes(sizes);
+}
 
 void ChainedIncludesSource::InitializeSema(Sema &S) {
   return getFinalReader().InitializeSema(S);