Migrate CFGReachabilityAnalysis out of the IdempotentOperationsChecker and into its own analysis file.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@126289 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 49 insertions, 0 deletions

diff --git a/include/clang/Analysis/Analyses/CFGReachabilityAnalysis.h b/include/clang/Analysis/Analyses/CFGReachabilityAnalysis.h
new file mode 100644
index 0000000000..72f644aaf0
--- /dev/null
+++ b/include/clang/Analysis/Analyses/CFGReachabilityAnalysis.h
@@ -0,0 +1,49 @@
+//==- CFGReachabilityAnalysis.h - Basic reachability analysis ----*- C++ -*-==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines a flow-sensitive, (mostly) path-insensitive reachability
+// analysis based on Clang's CFGs.  Clients can query if a given basic block
+// is reachable within the CFG.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef CLANG_ANALYSIS_CFG_REACHABILITY
+#define CLANG_ANALYSIS_CFG_REACHABILITY
+
+#include "llvm/ADT/BitVector.h"
+#include "llvm/ADT/DenseMap.h"
+
+namespace clang {
+
+class CFG;
+class CFGBlock;
+  
+// A class that performs reachability queries for CFGBlocks. Several internal
+// checks in this checker require reachability information. The requests all
+// tend to have a common destination, so we lazily do a predecessor search
+// from the destination node and cache the results to prevent work
+// duplication.
+class CFGReachabilityAnalysis {
+  typedef llvm::BitVector ReachableSet;
+  typedef llvm::DenseMap<unsigned, ReachableSet> ReachableMap;
+  ReachableSet analyzed;
+  ReachableMap reachable;
+public:
+  CFGReachabilityAnalysis(const CFG &cfg);
+
+  /// Returns true if the block 'Dst' can be reached from block 'Src'.
+  bool isReachable(const CFGBlock *Src, const CFGBlock *Dst);
+
+private:
+  void mapReachability(const CFGBlock *Dst);
+};
+  
+}
+
+#endif