[analyzer] Show paths for destructor calls.

This modifies BugReporter and friends to handle CallEnter and CallExitEnd
program points that came from implicit call CFG nodes (read: destructors).

This required some extra handling for nested implicit calls. For example,
the added multiple-inheritance test case has a call graph that looks like this:

testMultipleInheritance3
  ~MultipleInheritance
    ~SmartPointer
    ~Subclass
      ~SmartPointer
        ***bug here***

In this case we correctly notice that we started in an inlined function
when we reach the CallEnter program point for the second ~SmartPointer.
However, when we reach the next CallEnter (for ~Subclass), we were
accidentally re-using the inner ~SmartPointer call in the diagnostics.

Rather than guess if we saw the corresponding CallExitEnd based on the
contents of the active path, we now just ask the PathDiagnostic if there's
any known stack before popping off the top path.

(A similar issue could have occured without multiple inheritance, but there
wasn't a test case for it.)

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@160804 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 96 insertions, 64 deletions

diff --git a/lib/StaticAnalyzer/Core/BugReporter.cpp b/lib/StaticAnalyzer/Core/BugReporter.cpp
index 08588f60ab..12479ca53a 100644
--- a/lib/StaticAnalyzer/Core/BugReporter.cpp
+++ b/lib/StaticAnalyzer/Core/BugReporter.cpp
@@ -441,21 +441,23 @@ static void GenerateMinimalPathDiagnostic(PathDiagnostic& PD,
     }
     
     if (const CallEnter *CE = dyn_cast<CallEnter>(&P)) {
+      // Flush all locations, and pop the active path.
+      bool VisitedEntireCall = PD.isWithinCall();
       PD.popActivePath();
-      // The current active path should never be empty.  Either we
-      // just added a bunch of stuff to the top-level path, or
-      // we have a previous CallExitEnd.  If the front of the active
-      // path is not a PathDiagnosticCallPiece, it means that the
+
+      // Either we just added a bunch of stuff to the top-level path, or
+      // we have a previous CallExitEnd.  If the former, it means that the
       // path terminated within a function call.  We must then take the
       // current contents of the active path and place it within
       // a new PathDiagnosticCallPiece.
-      assert(!PD.getActivePath().empty());
-      PathDiagnosticCallPiece *C = 
-        dyn_cast<PathDiagnosticCallPiece>(PD.getActivePath().front());
-      if (!C) {
+      PathDiagnosticCallPiece *C;
+      if (VisitedEntireCall) {
+        C = cast<PathDiagnosticCallPiece>(PD.getActivePath().front());
+      } else {
         const Decl *Caller = CE->getLocationContext()->getDecl();
         C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller);
       }
+
       C->setCallee(*CE, SMgr);
       if (!CallStack.empty()) {
         assert(CallStack.back().first == C);
@@ -868,6 +870,7 @@ public:
   void rawAddEdge(PathDiagnosticLocation NewLoc);
 
   void addContext(const Stmt *S);
+  void addContext(const PathDiagnosticLocation &L);
   void addExtendedContext(const Stmt *S);
 };
 } // end anonymous namespace
@@ -1035,7 +1038,10 @@ void EdgeBuilder::addContext(const Stmt *S) {
     return;
 
   PathDiagnosticLocation L(S, PDB.getSourceManager(), PDB.LC);
+  addContext(L);
+}
 
+void EdgeBuilder::addContext(const PathDiagnosticLocation &L) {
   while (!CLocs.empty()) {
     const PathDiagnosticLocation &TopContextLoc = CLocs.back();
 
@@ -1151,25 +1157,22 @@ static void GenerateExtensivePathDiagnostic(PathDiagnostic& PD,
       }
       
       if (const CallExitEnd *CE = dyn_cast<CallExitEnd>(&P)) {
-        const StackFrameContext *LCtx =
-          CE->getLocationContext()->getCurrentStackFrame();
-        // FIXME: This needs to handle implicit calls.
-        if (const Stmt *S = CE->getCalleeContext()->getCallSite()) {
-          if (const Expr *Ex = dyn_cast<Expr>(S))
+        const Stmt *S = CE->getCalleeContext()->getCallSite();
+        if (const Expr *Ex = dyn_cast_or_null<Expr>(S)) {
             reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE,
                                                 N->getState().getPtr(), Ex,
                                                 N->getLocationContext());
-          PathDiagnosticLocation Loc(S,
-                                     PDB.getSourceManager(),
-                                     LCtx);
-          EB.addEdge(Loc, true);
-          EB.flushLocations();
-          PathDiagnosticCallPiece *C =
-            PathDiagnosticCallPiece::construct(N, *CE, SM);
-          PD.getActivePath().push_front(C);
-          PD.pushActivePath(&C->path);
-          CallStack.push_back(StackDiagPair(C, N));
         }
+        
+        PathDiagnosticCallPiece *C =
+          PathDiagnosticCallPiece::construct(N, *CE, SM);
+
+        EB.addEdge(C->callReturn, true);
+        EB.flushLocations();
+
+        PD.getActivePath().push_front(C);
+        PD.pushActivePath(&C->path);
+        CallStack.push_back(StackDiagPair(C, N));
         break;
       }
       
@@ -1183,30 +1186,26 @@ static void GenerateExtensivePathDiagnostic(PathDiagnostic& PD,
         EB.addEdge(pos);
         
         // Flush all locations, and pop the active path.
+        bool VisitedEntireCall = PD.isWithinCall();
         EB.flushLocations();
         PD.popActivePath();
-        assert(!PD.getActivePath().empty());
         PDB.LC = N->getLocationContext();
 
-        // The current active path should never be empty.  Either we
-        // just added a bunch of stuff to the top-level path, or
-        // we have a previous CallExitEnd.  If the front of the active
-        // path is not a PathDiagnosticCallPiece, it means that the
+        // Either we just added a bunch of stuff to the top-level path, or
+        // we have a previous CallExitEnd.  If the former, it means that the
         // path terminated within a function call.  We must then take the
         // current contents of the active path and place it within
         // a new PathDiagnosticCallPiece.
-        PathDiagnosticCallPiece *C =
-          dyn_cast<PathDiagnosticCallPiece>(PD.getActivePath().front());
-        if (!C) {
-          const Decl * Caller = CE->getLocationContext()->getDecl();
+        PathDiagnosticCallPiece *C;
+        if (VisitedEntireCall) {
+          C = cast<PathDiagnosticCallPiece>(PD.getActivePath().front());
+        } else {
+          const Decl *Caller = CE->getLocationContext()->getDecl();
           C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller);
         }
 
-        // FIXME: We still need a location for implicit calls.
-        if (CE->getCallExpr()) {
-          C->setCallee(*CE, SM);
-          EB.addContext(CE->getCallExpr());
-        }
+        C->setCallee(*CE, SM);
+        EB.addContext(C->getLocation());
 
         if (!CallStack.empty()) {
           assert(CallStack.back().first == C);
diff --git a/lib/StaticAnalyzer/Core/ExprEngineCallAndReturn.cpp b/lib/StaticAnalyzer/Core/ExprEngineCallAndReturn.cpp
index 4431c03d49..89d1e27c3d 100644
--- a/lib/StaticAnalyzer/Core/ExprEngineCallAndReturn.cpp
+++ b/lib/StaticAnalyzer/Core/ExprEngineCallAndReturn.cpp
@@ -293,6 +293,11 @@ bool ExprEngine::inlineCall(const CallEvent &Call,
     if (!ADC->getCFGBuildOptions().AddImplicitDtors ||
         !ADC->getCFGBuildOptions().AddInitializers)
       return false;
+    // FIXME: This is a hack. We only process VarDecl destructors right now,
+    // so we should only inline VarDecl constructors.
+    if (const CXXConstructorCall *Ctor = dyn_cast<CXXConstructorCall>(&Call))
+      if (!isa<VarRegion>(Ctor->getCXXThisVal().getAsRegion()))
+        return false;
     break;
   }
   case CE_CXXAllocator:
diff --git a/lib/StaticAnalyzer/Core/PathDiagnostic.cpp b/lib/StaticAnalyzer/Core/PathDiagnostic.cpp
index bfb8bf6432..5496df0f8f 100644
--- a/lib/StaticAnalyzer/Core/PathDiagnostic.cpp
+++ b/lib/StaticAnalyzer/Core/PathDiagnostic.cpp
@@ -16,6 +16,7 @@
 #include "clang/Basic/SourceManager.h"
 #include "clang/AST/Expr.h"
 #include "clang/AST/Decl.h"
+#include "clang/AST/DeclCXX.h"
 #include "clang/AST/DeclObjC.h"
 #include "clang/AST/ParentMap.h"
 #include "clang/AST/StmtCXX.h"
@@ -242,13 +243,14 @@ PathDiagnosticConsumer::FlushDiagnostics(SmallVectorImpl<std::string> *Files) {
 //===----------------------------------------------------------------------===//
 
 static SourceLocation getValidSourceLocation(const Stmt* S,
-                                             LocationOrAnalysisDeclContext LAC) {
-  SourceLocation L = S->getLocStart();
+                                             LocationOrAnalysisDeclContext LAC,
+                                             bool UseEnd = false) {
+  SourceLocation L = UseEnd ? S->getLocEnd() : S->getLocStart();
   assert(!LAC.isNull() && "A valid LocationContext or AnalysisDeclContext should "
                           "be passed to PathDiagnosticLocation upon creation.");
 
   // S might be a temporary statement that does not have a location in the
-  // source code, so find an enclosing statement and use it's location.
+  // source code, so find an enclosing statement and use its location.
   if (!L.isValid()) {
 
     ParentMap *PM = 0;
@@ -259,7 +261,7 @@ static SourceLocation getValidSourceLocation(const Stmt* S,
 
     while (!L.isValid()) {
       S = PM->getParent(S);
-      L = S->getLocStart();
+      L = UseEnd ? S->getLocEnd() : S->getLocStart();
     }
   }
 
@@ -280,6 +282,17 @@ PathDiagnosticLocation
                                 SM, SingleLocK);
 }
 
+
+PathDiagnosticLocation
+PathDiagnosticLocation::createEnd(const Stmt *S,
+                                  const SourceManager &SM,
+                                  LocationOrAnalysisDeclContext LAC) {
+  if (const CompoundStmt *CS = dyn_cast<CompoundStmt>(S))
+    return createEndBrace(CS, SM);
+  return PathDiagnosticLocation(getValidSourceLocation(S, LAC, /*End=*/true),
+                                SM, SingleLocK);
+}
+
 PathDiagnosticLocation
   PathDiagnosticLocation::createOperatorLoc(const BinaryOperator *BO,
                                             const SourceManager &SM) {
@@ -339,9 +352,6 @@ PathDiagnosticLocation
   else if (const PostStmt *PS = dyn_cast<PostStmt>(&P)) {
     S = PS->getStmt();
   }
-  else if (const CallExitEnd *CEE = dyn_cast<CallExitEnd>(&P)) {
-    S = CEE->getCalleeContext()->getCallSite();
-  }
 
   return PathDiagnosticLocation(S, SMng, P.getLocationContext());
 }
@@ -498,21 +508,36 @@ PathDiagnosticLocation PathDiagnostic::getLocation() const {
 // Manipulation of PathDiagnosticCallPieces.
 //===----------------------------------------------------------------------===//
 
-static PathDiagnosticLocation getLastStmtLoc(const ExplodedNode *N,
-                                             const SourceManager &SM) {
-  while (N) {
-    ProgramPoint PP = N->getLocation();
-    if (const StmtPoint *SP = dyn_cast<StmtPoint>(&PP))
-      return PathDiagnosticLocation(SP->getStmt(), SM, PP.getLocationContext());
-    // FIXME: Handle implicit calls.
-    if (const CallExitEnd *CEE = dyn_cast<CallExitEnd>(&PP))
-      if (const Stmt *CallSite = CEE->getCalleeContext()->getCallSite())
-        return PathDiagnosticLocation(CallSite, SM, PP.getLocationContext());
-    if (N->pred_empty())
-      break;
-    N = *N->pred_begin();
+static PathDiagnosticLocation
+getLocationForCaller(const StackFrameContext *SFC,
+                     const LocationContext *CallerCtx,
+                     const SourceManager &SM) {
+  const CFGBlock &Block = *SFC->getCallSiteBlock();
+  CFGElement Source = Block[SFC->getIndex()];
+
+  switch (Source.getKind()) {
+  case CFGElement::Invalid:
+    llvm_unreachable("Invalid CFGElement");
+  case CFGElement::Statement:
+    return PathDiagnosticLocation(cast<CFGStmt>(Source).getStmt(),
+                                  SM, CallerCtx);
+  case CFGElement::Initializer: {
+    const CFGInitializer &Init = cast<CFGInitializer>(Source);
+    return PathDiagnosticLocation(Init.getInitializer()->getInit(),
+                                  SM, CallerCtx);
   }
-  return PathDiagnosticLocation();
+  case CFGElement::AutomaticObjectDtor: {
+    const CFGAutomaticObjDtor &Dtor = cast<CFGAutomaticObjDtor>(Source);
+    return PathDiagnosticLocation::createEnd(Dtor.getTriggerStmt(),
+                                             SM, CallerCtx);
+  }
+  case CFGElement::BaseDtor:
+  case CFGElement::MemberDtor:
+  case CFGElement::TemporaryDtor:
+    llvm_unreachable("not yet implemented!");
+  }
+
+  llvm_unreachable("Unknown CFGElement kind");
 }
 
 PathDiagnosticCallPiece *
@@ -520,7 +545,9 @@ PathDiagnosticCallPiece::construct(const ExplodedNode *N,
                                    const CallExitEnd &CE,
                                    const SourceManager &SM) {
   const Decl *caller = CE.getLocationContext()->getDecl();
-  PathDiagnosticLocation pos = getLastStmtLoc(N, SM);
+  PathDiagnosticLocation pos = getLocationForCaller(CE.getCalleeContext(),
+                                                    CE.getLocationContext(),
+                                                    SM);
   return new PathDiagnosticCallPiece(caller, pos);
 }
 
@@ -535,11 +562,11 @@ PathDiagnosticCallPiece::construct(PathPieces &path,
 
 void PathDiagnosticCallPiece::setCallee(const CallEnter &CE,
                                         const SourceManager &SM) {
-  const Decl *D = CE.getCalleeContext()->getDecl();
-  Callee = D;
-  callEnter = PathDiagnosticLocation(CE.getCallExpr(), SM,
-                                     CE.getLocationContext());
-  callEnterWithin = PathDiagnosticLocation::createBegin(D, SM);
+  const StackFrameContext *CalleeCtx = CE.getCalleeContext();
+  Callee = CalleeCtx->getDecl();
+
+  callEnterWithin = PathDiagnosticLocation::createBegin(Callee, SM);
+  callEnter = getLocationForCaller(CalleeCtx, CE.getLocationContext(), SM);
 }
 
 IntrusiveRefCntPtr<PathDiagnosticEventPiece>
@@ -677,6 +704,7 @@ std::string StackHintGeneratorForSymbol::getMessage(const ExplodedNode *N){
   const CallExitEnd *CExit = dyn_cast<CallExitEnd>(&P);
   assert(CExit && "Stack Hints should be constructed at CallExitEnd points.");
 
+  // FIXME: Use CallEvent to abstract this over all calls.
   const Stmt *CallSite = CExit->getCalleeContext()->getCallSite();
   const CallExpr *CE = dyn_cast_or_null<CallExpr>(CallSite);
   if (!CE)