[llvm-mca] Unify the API for the various views. NFCI

This allows the customization of the performance report.

Users can specify their own custom sequence of views.
Each view contributes a portion of the performance report generated by the
BackendPrinter.

Internally, class BackendPrinter keeps a sequence of views; views are printed
out in sequence when method 'printReport()' is called. 

This patch addresses one of the two review comments from Clement in D43951.

llvm-svn: 327018

1 files changed, 21 insertions, 0 deletions

diff --git a/llvm/tools/llvm-mca/View.cpp b/llvm/tools/llvm-mca/View.cpp
new file mode 100644
index 00000000000..1b54e4ea022
--- /dev/null
+++ b/llvm/tools/llvm-mca/View.cpp
@@ -0,0 +1,21 @@
+//===----------------------- View.cpp ---------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+/// \file
+///
+/// This file defines the virtual anchor method in View.h to pin the vtable.
+///
+//===----------------------------------------------------------------------===//
+
+#include "View.h"
+
+namespace mca {
+
+void View::anchor() {}
+
+} // namespace mca