1 files changed, 49 insertions, 0 deletions
diff --git a/clang/lib/Analysis/PostOrderCFGView.cpp b/clang/lib/Analysis/PostOrderCFGView.cpp
new file mode 100644
index 000000000000..f79d0007cb3d
--- /dev/null
+++ b/clang/lib/Analysis/PostOrderCFGView.cpp
@@ -0,0 +1,49 @@
+//===- PostOrderCFGView.cpp - Post order view of CFG blocks ---------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements post order view of the blocks in a CFG.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Analysis/Analyses/PostOrderCFGView.h"
+#include "clang/Analysis/AnalysisDeclContext.h"
+#include "clang/Analysis/CFG.h"
+
+using namespace clang;
+
+void PostOrderCFGView::anchor() {}
+
+PostOrderCFGView::PostOrderCFGView(const CFG *cfg) {
+  Blocks.reserve(cfg->getNumBlockIDs());
+  CFGBlockSet BSet(cfg);
+
+  for (po_iterator I = po_iterator::begin(cfg, BSet),
+                   E = po_iterator::end(cfg, BSet); I != E; ++I) {
+    BlockOrder[*I] = Blocks.size() + 1;
+    Blocks.push_back(*I);
+  }
+}
+
+PostOrderCFGView *PostOrderCFGView::create(AnalysisDeclContext &ctx) {
+  const CFG *cfg = ctx.getCFG();
+  if (!cfg)
+    return nullptr;
+  return new PostOrderCFGView(cfg);
+}
+
+const void *PostOrderCFGView::getTag() { static int x; return &x; }
+
+bool PostOrderCFGView::BlockOrderCompare::operator()(const CFGBlock *b1,
+                                                     const CFGBlock *b2) const {
+  PostOrderCFGView::BlockOrderTy::const_iterator b1It = POV.BlockOrder.find(b1);
+  PostOrderCFGView::BlockOrderTy::const_iterator b2It = POV.BlockOrder.find(b2);
+
+  unsigned b1V = (b1It == POV.BlockOrder.end()) ? 0 : b1It->second;
+  unsigned b2V = (b2It == POV.BlockOrder.end()) ? 0 : b2It->second;
+  return b1V > b2V;
+}