[analyzer] Highlight nodes which have error reports in them in red in exploded graph

[george.karpenkov]

Summary

Add "blue" to the outline of nodes which have sinks.

Presenting the legend remains to be figured out.

[NoQ]

I still think we need to add some text as well, not just color.

[george.karpenkov]

@NoQ done

[NoQ]

Yay!

[Szelethus]

clang/lib/StaticAnalyzer/Core/ExprEngine.cpp

2957

Nit: missing space: static_cast<ExprEngine *>

[george.karpenkov]

clang/lib/StaticAnalyzer/Core/ExprEngine.cpp

2957

OK! Maybe I should just run clang-format automagically

clang/lib/StaticAnalyzer/Core/ExprEngine.cpp

 
 #ifndef NDEBUG
 namespace llvm {
 
 template<>
 struct DOTGraphTraits<ExplodedGraph*> : public DefaultDOTGraphTraits {
   DOTGraphTraits (bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {}
 
-  // FIXME: Since we do not cache error nodes in ExprEngine now, this does not
-  // work.
+  static bool nodeHasBugReport(const ExplodedNode *N) {
+    BugReporter &BR = static_cast<ExprEngine*>(
+      N->getState()->getStateManager().getOwningEngine())->getBugReporter();
+
+    const auto EQClasses =
+        llvm::make_range(BR.EQClasses_begin(), BR.EQClasses_end());
+
+    for (const auto &EQ : EQClasses) {
+      for (const BugReport &Report : EQ) {
+        if (Report.getErrorNode() == N)
+          return true;
+      }
+    }
+    return false;
+  }
+
+  static bool nodeOrHiddenPredecessorHasProperty(
+      const ExplodedNode *N,
+      llvm::function_ref<bool(const ExplodedNode *)> Property) {
+    const ExplodedNode *FirstHiddenNode = findFirstHiddenNode(N);
+    const ExplodedNode *OtherNode = FirstHiddenNode;
+    while (true) {
+      if (Property(OtherNode))
+        return true;
+
+      if (OtherNode == N)
+        break;
+
+      OtherNode = *OtherNode->succ_begin();
+    }
+    return false;
+  }
+
   static std::string getNodeAttributes(const ExplodedNode *N,
                                        ExplodedGraph *G) {
-    if (N->isSink())
-      return "color=red";
-    return {};
+    SmallVector<StringRef, 10> Out;
+    if (nodeOrHiddenPredecessorHasProperty(N, &nodeHasBugReport)) {
+      Out.push_back("style=filled");
+      Out.push_back("fillcolor=red");
+    }
+    if (nodeOrHiddenPredecessorHasProperty(
+            N, [](const ExplodedNode *C) { return C->isSink(); }))
+      Out.push_back("color=blue");
+    return llvm::join(Out, ",");
   }
 
   static bool isNodeHidden(const ExplodedNode *N) {
     return N->isTrivial();
   }
 
+  static const ExplodedNode * findFirstHiddenNode(const ExplodedNode *N) {
+    const ExplodedNode *FirstHiddenNode = N;
+    while (FirstHiddenNode->pred_size() == 1 &&
+           isNodeHidden(*FirstHiddenNode->pred_begin())) {
+      FirstHiddenNode = *FirstHiddenNode->pred_begin();
+    }
+    return FirstHiddenNode;
+  }
+
   static std::string getNodeLabel(const ExplodedNode *N, ExplodedGraph *G){
     std::string sbuf;
     llvm::raw_string_ostream Out(sbuf);
 
     // Find the first node which program point and tag has to be included in
     // the output.
-    const ExplodedNode *FirstHiddenNode = N;
-    while (FirstHiddenNode->pred_size() == 1 &&
-           isNodeHidden(*FirstHiddenNode->pred_begin())) {
-      FirstHiddenNode = *FirstHiddenNode->pred_begin();
-    }
+    const ExplodedNode *FirstHiddenNode = findFirstHiddenNode(N);
 
     ProgramStateRef State = N->getState();
     const ASTContext &Context = State->getStateManager().getContext();
 
     // Dump program point for all the previously skipped nodes.
     const ExplodedNode *OtherNode = FirstHiddenNode;
     while (true) {
       OtherNode->getLocation().dump(Context, "\\l", Out);