[analyzer] [NFC] Factor out generating path diagnostics for a statement into a function

[george.karpenkov]

Summary

Phabricator diff fails to detect the move, so probably easier to look at two files side-by-side.

[NoQ]

Is the new function usable for other diagnostic generators? Or should we call it generateMinimalDiagnosticsForStmt()?

[george.karpenkov]

@NoQ a good point, extended refactoring across all diagnostics types.

[NoQ]

Yeah, that's a lot less loops to worry about.

lib/StaticAnalyzer/Core/BugReporter.cpp

if (ep->hasCallStackHint())
         if  (!CP->hasCallStackMessage())
           CP->setCallStackMessage(stackMsg);
       }
   }
 }
 
 static void CompactPathDiagnostic(PathPieces &path, const SourceManager& SM);
 
-static bool GenerateMinimalPathDiagnostic(
-    PathDiagnostic &PD, PathDiagnosticBuilder &PDB, const ExplodedNode *N,
-    LocationContextMap &LCM,
-    ArrayRef<std::unique_ptr<BugReporterVisitor>> visitors) {
-
-  SourceManager& SMgr = PDB.getSourceManager();
-  const LocationContext *LC = PDB.LC;
-  const ExplodedNode *NextNode = N->pred_empty()
-                                        ? nullptr : *(N->pred_begin());
-
-  StackDiagVector CallStack;
-
-  while (NextNode) {
-    N = NextNode;
-    PDB.LC = N->getLocationContext();
-    NextNode = N->getFirstPred();
-
-    ProgramPoint P = N->getLocation();
-
-    do {
-      if (Optional<CallExitEnd> CE = P.getAs<CallExitEnd>()) {
-        auto C = PathDiagnosticCallPiece::construct(N, *CE, SMgr);
-        // Record the mapping from call piece to LocationContext.
-        LCM[&C->path] = CE->getCalleeContext();
-        auto *P = C.get();
-        PD.getActivePath().push_front(std::move(C));
-        PD.pushActivePath(&P->path);
-        CallStack.push_back(StackDiagPair(P, N));
-        break;
-      }
-
-      if (Optional<CallEnter> CE = P.getAs<CallEnter>()) {
-        // Flush all locations, and pop the active path.
-        bool VisitedEntireCall = PD.isWithinCall();
-        PD.popActivePath();
-
-        // 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;
-        if (VisitedEntireCall) {
-          C = cast<PathDiagnosticCallPiece>(PD.getActivePath().front().get());
-        } else {
-          const Decl *Caller = CE->getLocationContext()->getDecl();
-          C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller);
-          // Record the mapping from call piece to LocationContext.
-          LCM[&C->path] = CE->getCalleeContext();
-        }
-
-        C->setCallee(*CE, SMgr);
-        if (!CallStack.empty()) {
-          assert(CallStack.back().first == C);
-          CallStack.pop_back();
-        }
-        break;
-      }
-
-      if (Optional<BlockEdge> BE = P.getAs<BlockEdge>()) {
-        const CFGBlock *Src = BE->getSrc();
-        const CFGBlock *Dst = BE->getDst();
-        const Stmt *T = Src->getTerminator();
-
-        if (!T)
-          break;
-
-        PathDiagnosticLocation Start =
-            PathDiagnosticLocation::createBegin(T, SMgr,
-                N->getLocationContext());
+static void generateDiagnosticsForStmt(const Stmt *T,
+                                       const ExplodedNode *N,
+                                       PathDiagnosticBuilder &PDB,
+                                       const LocationContext *LC,
+                                       const CFGBlock *Src,
+                                       const CFGBlock *Dst,
+                                       SourceManager &SMgr,
+                                       PathDiagnostic &PD) {
 
-        switch (T->getStmtClass()) {
-        default:
-          break;
+  auto Start = PathDiagnosticLocation::createBegin(T, SMgr, LC);
 
-        case Stmt::GotoStmtClass:
-        case Stmt::IndirectGotoStmtClass: {
-          const Stmt *S = PathDiagnosticLocation::getNextStmt(N);
 
-          if (!S)
-            break;
 
-          std::string sbuf;
-          llvm::raw_string_ostream os(sbuf);
-          const PathDiagnosticLocation &End = PDB.getEnclosingStmtLocation(S);
 
-          os << "Control jumps to line "
-              << End.asLocation().getExpansionLineNumber();
-          PD.getActivePath().push_front(
-              std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
-                                                               os.str()));
-          break;
-        }
+    os << "Control jumps to line " << End.asLocation().getExpansionLineNumber();
+        std::make_shared<PathDiagnosticControlFlowPiece>(Start, End, os.str()));
 
-        case Stmt::SwitchStmtClass: {
-          // Figure out what case arm we took.
-          std::string sbuf;
-          llvm::raw_string_ostream os(sbuf);
 
-          if (const Stmt *S = Dst->getLabel()) {
-            PathDiagnosticLocation End(S, SMgr, LC);
 
-            switch (S->getStmtClass()) {
-            default:
-              os << "No cases match in the switch statement. "
               "Control jumps to line "
-              << End.asLocation().getExpansionLineNumber();
-              break;
-            case Stmt::DefaultStmtClass:
-              os << "Control jumps to the 'default' case at line "
-              << End.asLocation().getExpansionLineNumber();
-              break;
 
-            case Stmt::CaseStmtClass: {
-              os << "Control jumps to 'case ";
-              const CaseStmt *Case = cast<CaseStmt>(S);
-              const Expr *LHS = Case->getLHS()->IgnoreParenCasts();
 
-              // Determine if it is an enum.
-              bool GetRawInt = true;
 
-              if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(LHS)) {
-                // FIXME: Maybe this should be an assertion.  Are there cases
-                // were it is not an EnumConstantDecl?
-                const EnumConstantDecl *D =
-                    dyn_cast<EnumConstantDecl>(DR->getDecl());
+          const EnumConstantDecl *D = dyn_cast<EnumConstantDecl>(DR->getDecl());
 
-                if (D) {
-                  GetRawInt = false;
-                  os << *D;
-                }
-              }
 
-              if (GetRawInt)
-                os << LHS->EvaluateKnownConstInt(PDB.getASTContext());
 
-              os << ":'  at line "
-                  << End.asLocation().getExpansionLineNumber();
-              break;
-            }
-            }
-            PD.getActivePath().push_front(
-                std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
-                                                                 os.str()));
-          }
-          else {
-            os << "'Default' branch taken. ";
-            const PathDiagnosticLocation &End = PDB.ExecutionContinues(os, N);
-            PD.getActivePath().push_front(
-                std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
-                                                                 os.str()));
-          }
+        os << ":'  at line " << End.asLocation().getExpansionLineNumber();
+    } else {
 
-          break;
-        }
 
-        case Stmt::BreakStmtClass:
-        case Stmt::ContinueStmtClass: {
-          std::string sbuf;
-          llvm::raw_string_ostream os(sbuf);
-          PathDiagnosticLocation End = PDB.ExecutionContinues(os, N);
-          PD.getActivePath().push_front(
-              std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
-                                                               os.str()));
-          break;
-        }
+        std::make_shared<PathDiagnosticControlFlowPiece>(Start, End, os.str()));
 
-        // Determine control-flow for ternary '?'.
-        case Stmt::BinaryConditionalOperatorClass:
-        case Stmt::ConditionalOperatorClass: {
-          std::string sbuf;
-          llvm::raw_string_ostream os(sbuf);
-          os << "'?' condition is ";
 
-          if (*(Src->succ_begin()+1) == Dst)
-            os << "false";
-          else
-            os << "true";
+    if (*(Src->succ_begin() + 1) == Dst)
 
-          PathDiagnosticLocation End = PDB.ExecutionContinues(N);
 
-          if (const Stmt *S = End.asStmt())
-            End = PDB.getEnclosingStmtLocation(S);
 
-          PD.getActivePath().push_front(
-              std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
-                                                               os.str()));
-          break;
-        }
+        std::make_shared<PathDiagnosticControlFlowPiece>(Start, End, os.str()));
 
-        // Determine control-flow for short-circuited '&&' and '||'.
-        case Stmt::BinaryOperatorClass: {
-          if (!PDB.supportsLogicalOpControlFlow())
-            break;
 
-          const BinaryOperator *B = cast<BinaryOperator>(T);
-          std::string sbuf;
-          llvm::raw_string_ostream os(sbuf);
-          os << "Left side of '";
 
-          if (B->getOpcode() == BO_LAnd) {
-            os << "&&" << "' is ";
+      os << "&&"
+         << "' is ";
 
-            if (*(Src->succ_begin()+1) == Dst) {
-              os << "false";
-              PathDiagnosticLocation End(B->getLHS(), SMgr, LC);
-              PathDiagnosticLocation Start =
-                  PathDiagnosticLocation::createOperatorLoc(B, SMgr);
-              PD.getActivePath().push_front(
-                  std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
-                                                                   os.str()));
-            }
-            else {
-              os << "true";
-              PathDiagnosticLocation Start(B->getLHS(), SMgr, LC);
-              PathDiagnosticLocation End = PDB.ExecutionContinues(N);
-              PD.getActivePath().push_front(
-                  std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
-                                                                   os.str()));
-            }
-          }
-          else {
-            assert(B->getOpcode() == BO_LOr);
-            os << "||" << "' is ";
+      if (*(Src->succ_begin() + 1) == Dst) {
+      } else {
+    } else {
+      os << "||"
+         << "' is ";
 
-            if (*(Src->succ_begin()+1) == Dst) {
-              os << "false";
-              PathDiagnosticLocation Start(B->getLHS(), SMgr, LC);
-              PathDiagnosticLocation End = PDB.ExecutionContinues(N);
-              PD.getActivePath().push_front(
-                  std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
-                                                                   os.str()));
-            }
-            else {
-              os << "true";
-              PathDiagnosticLocation End(B->getLHS(), SMgr, LC);
-              PathDiagnosticLocation Start =
-                  PathDiagnosticLocation::createOperatorLoc(B, SMgr);
-              PD.getActivePath().push_front(
-                  std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
-                                                                   os.str()));
-            }
-          }
+      if (*(Src->succ_begin() + 1) == Dst) {
+      } else {
 
-          break;
-        }
 
-        case Stmt::DoStmtClass:  {
-          if (*(Src->succ_begin()) == Dst) {
-            std::string sbuf;
-            llvm::raw_string_ostream os(sbuf);
+  case Stmt::DoStmtClass: {
 
-            os << "Loop condition is true. ";
-            PathDiagnosticLocation End = PDB.ExecutionContinues(os, N);
 
-            if (const Stmt *S = End.asStmt())
-              End = PDB.getEnclosingStmtLocation(S);
 
-            PD.getActivePath().push_front(
-                std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
-                                                                 os.str()));
-          }
-          else {
-            PathDiagnosticLocation End = PDB.ExecutionContinues(N);
+    } else {
 
-            if (const Stmt *S = End.asStmt())
-              End = PDB.getEnclosingStmtLocation(S);
 
-            PD.getActivePath().push_front(
-                std::make_shared<PathDiagnosticControlFlowPiece>(
-                    Start, End, "Loop condition is false.  Exiting loop"));
-          }
 
-          break;
-        }
 
-        case Stmt::WhileStmtClass:
-        case Stmt::ForStmtClass: {
-          if (*(Src->succ_begin()+1) == Dst) {
-            std::string sbuf;
-            llvm::raw_string_ostream os(sbuf);
+    if (*(Src->succ_begin() + 1) == Dst) {
 
-            os << "Loop condition is false. ";
-            PathDiagnosticLocation End = PDB.ExecutionContinues(os, N);
-            if (const Stmt *S = End.asStmt())
-              End = PDB.getEnclosingStmtLocation(S);
 
-            PD.getActivePath().push_front(
-                std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
-                                                                 os.str()));
-          }
-          else {
-            PathDiagnosticLocation End = PDB.ExecutionContinues(N);
-            if (const Stmt *S = End.asStmt())
-              End = PDB.getEnclosingStmtLocation(S);
+    } else {
 
-            PD.getActivePath().push_front(
-                std::make_shared<PathDiagnosticControlFlowPiece>(
-                    Start, End, "Loop condition is true.  Entering loop body"));
-          }
 
-          break;
-        }
 
-        case Stmt::IfStmtClass: {
-          PathDiagnosticLocation End = PDB.ExecutionContinues(N);
 
-          if (const Stmt *S = End.asStmt())
-            End = PDB.getEnclosingStmtLocation(S);
 
-          if (*(Src->succ_begin()+1) == Dst)
-            PD.getActivePath().push_front(
-                std::make_shared<PathDiagnosticControlFlowPiece>(
-                    Start, End, "Taking false branch"));
-          else
-            PD.getActivePath().push_front(
-                std::make_shared<PathDiagnosticControlFlowPiece>(
-                    Start, End, "Taking true branch"));
+    if (*(Src->succ_begin() + 1) == Dst)
 
-          break;
-        }
-        }
-      }
-    } while(0);
+
+static bool GenerateMinimalPathDiagnostic(
+    PathDiagnostic &PD, PathDiagnosticBuilder &PDB, const ExplodedNode *N,
+    LocationContextMap &LCM,
+    ArrayRef<std::unique_ptr<BugReporterVisitor>> visitors) {
+
+  SourceManager& SMgr = PDB.getSourceManager();
+  const LocationContext *LC = PDB.LC;
+  const ExplodedNode *NextNode = N->pred_empty()
+                                        ? nullptr : *(N->pred_begin());
+
+  StackDiagVector CallStack;
+
+  while (NextNode) {
+    N = NextNode;
+    PDB.LC = N->getLocationContext();
+    NextNode = N->getFirstPred();
+
+    ProgramPoint P = N->getLocation();
+
+    if (Optional<CallExitEnd> CE = P.getAs<CallExitEnd>()) {
+      auto C = PathDiagnosticCallPiece::construct(N, *CE, SMgr);
+      // Record the mapping from call piece to LocationContext.
+      LCM[&C->path] = CE->getCalleeContext();
+      auto *P = C.get();
+      PD.getActivePath().push_front(std::move(C));
+      PD.pushActivePath(&P->path);
+      CallStack.push_back(StackDiagPair(P, N));
+    } else if (Optional<CallEnter> CE = P.getAs<CallEnter>()) {
+      // Flush all locations, and pop the active path.
+      bool VisitedEntireCall = PD.isWithinCall();
+      PD.popActivePath();
+
+      // 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;
+      if (VisitedEntireCall) {
+        C = cast<PathDiagnosticCallPiece>(PD.getActivePath().front().get());
+      } else {
+        const Decl *Caller = CE->getLocationContext()->getDecl();
+        C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller);
+        // Record the mapping from call piece to LocationContext.
+        LCM[&C->path] = CE->getCalleeContext();
+      }
+
+      C->setCallee(*CE, SMgr);
+      if (!CallStack.empty()) {
+        assert(CallStack.back().first == C);
+        CallStack.pop_back();
+      }
+    } else if (Optional<BlockEdge> BE = P.getAs<BlockEdge>()) {
+      const CFGBlock *Src = BE->getSrc();
+      const CFGBlock *Dst = BE->getDst();
+
+      if (const Stmt *T = Src->getTerminator())
+        generateDiagnosticsForStmt(T, N, PDB, LC, Src, Dst, SMgr, PD);
+    }
 
     if (NextNode) {
       // Add diagnostic pieces from custom visitors.
       BugReport *R = PDB.getBugReport();
       llvm::FoldingSet<PathDiagnosticPiece> DeduplicationSet;
       for (auto &V : visitors) {
         if (auto p = V->VisitNode(N, NextNode, PDB, *R)) {
           if (DeduplicationSet.GetOrInsertNode(p.get()) != p.get())