r273572 - [Analyzer] Don't cache report generation ExplodedNodes

Ben Craig via cfe-commits cfe-commits at lists.llvm.org
Thu Jun 23 08:47:12 PDT 2016

Author: bcraig
Date: Thu Jun 23 10:47:12 2016
New Revision: 273572

URL: http://llvm.org/viewvc/llvm-project?rev=273572&view=rev
[Analyzer] Don't cache report generation ExplodedNodes

During the core analysis, ExplodedNodes are added to the
ExplodedGraph, and those nodes are cached for deduplication purposes.

After core analysis, reports are generated. Here, trimmed copies of
the ExplodedGraph are made. Since the ExplodedGraph has already been
deduplicated, there is no need to deduplicate again.

This change makes it possible to add ExplodedNodes to an
ExplodedGraph without the overhead of deduplication. "Uncached" nodes
also cannot be iterated over, but none of the report generation code
attempts to iterate over all nodes. This change reduces the analysis
time of a large .C file from 3m43.941s to 3m40.256s (~1.6% speedup).
It should slightly reduce memory consumption. Gains should be roughly
proportional to the number (and path length) of static analysis

This patch enables future work that should remove the need for an
InterExplodedGraphMap inverse map. I plan on using the (now unused)
ExplodedNode link to connect new nodes to the original nodes.



Modified: cfe/trunk/include/clang/StaticAnalyzer/Core/PathSensitive/ExplodedGraph.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/StaticAnalyzer/Core/PathSensitive/ExplodedGraph.h?rev=273572&r1=273571&r2=273572&view=diff
--- cfe/trunk/include/clang/StaticAnalyzer/Core/PathSensitive/ExplodedGraph.h (original)
+++ cfe/trunk/include/clang/StaticAnalyzer/Core/PathSensitive/ExplodedGraph.h Thu Jun 23 10:47:12 2016
@@ -295,6 +295,14 @@ public:
                         bool IsSink = false,
                         bool* IsNew = nullptr);
+  /// \brief Create a node for a (Location, State) pair,
+  ///  but don't store it for deduplication later.  This
+  ///  is useful when copying an already completed
+  ///  ExplodedGraph for further processing.
+  ExplodedNode *createUncachedNode(const ProgramPoint &L,
+    ProgramStateRef State,
+    bool IsSink = false);
   std::unique_ptr<ExplodedGraph> MakeEmptyGraph() const {
     return llvm::make_unique<ExplodedGraph>();

Modified: cfe/trunk/lib/StaticAnalyzer/Core/BugReporter.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Core/BugReporter.cpp?rev=273572&r1=273571&r2=273572&view=diff
--- cfe/trunk/lib/StaticAnalyzer/Core/BugReporter.cpp (original)
+++ cfe/trunk/lib/StaticAnalyzer/Core/BugReporter.cpp Thu Jun 23 10:47:12 2016
@@ -2922,7 +2922,7 @@ bool TrimmedGraph::popNextReportGraph(Re
   while (true) {
     // Create the equivalent node in the new graph with the same state
     // and location.
-    ExplodedNode *NewN = GNew->getNode(OrigN->getLocation(), OrigN->getState(),
+    ExplodedNode *NewN = GNew->createUncachedNode(OrigN->getLocation(), OrigN->getState(),
     // Store the mapping to the original node.

Modified: cfe/trunk/lib/StaticAnalyzer/Core/ExplodedGraph.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Core/ExplodedGraph.cpp?rev=273572&r1=273571&r2=273572&view=diff
--- cfe/trunk/lib/StaticAnalyzer/Core/ExplodedGraph.cpp (original)
+++ cfe/trunk/lib/StaticAnalyzer/Core/ExplodedGraph.cpp Thu Jun 23 10:47:12 2016
@@ -336,6 +336,14 @@ ExplodedNode *ExplodedGraph::getNode(con
   return V;
+ExplodedNode *ExplodedGraph::createUncachedNode(const ProgramPoint &L,
+                                                ProgramStateRef State,
+                                                bool IsSink) {
+  NodeTy *V = (NodeTy *) getAllocator().Allocate<NodeTy>();
+  new (V) NodeTy(L, State, IsSink);
+  return V;
 ExplodedGraph::trim(ArrayRef<const NodeTy *> Sinks,
                     InterExplodedGraphMap *ForwardMap,
@@ -395,8 +403,7 @@ ExplodedGraph::trim(ArrayRef<const NodeT
     // Create the corresponding node in the new graph and record the mapping
     // from the old node to the new node.
-    ExplodedNode *NewN = G->getNode(N->getLocation(), N->State, N->isSink(),
-                                    nullptr);
+    ExplodedNode *NewN = G->createUncachedNode(N->getLocation(), N->State, N->isSink());
     Pass2[N] = NewN;
     // Also record the reverse mapping from the new node to the old node.

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