[analyzer][NFC] Use CallEvent checker callback in GenericTaintChecker

[steakhal]

Summary

Intended to be a non-functional change but it turned out CallEvent handles constructor calls unlike CallExpr which doesn't triggered for constructors.

All in all, this change shouldn't be observable since constructors are not yet propagating taintness like functions.
In the future constructors should propagate taintness as well.

This change includes:

• NFCi change all uses of the CallExpr to CallEvent
• NFC rename some functions, mark static them etc.
• NFC omit explicit TaintPropagationRule type in switches
• NFC apply some clang-tidy fixits

[steakhal]

clang/lib/StaticAnalyzer/Checkers/GenericTaintChecker.cpp

358

I'm not sure why should we adjust (workaround) the number of arguments of CXXInstanceCalls calls, can someone explain it to me?

The same question raised for getArg too.

554

I'm not sure if this is the right way.

[NoQ]

clang/lib/StaticAnalyzer/Checkers/GenericTaintChecker.cpp

358

Remove this :)

I think this is about this inconsistency with operator calls where one of {decl, expr} treats this as an argument, but the other doesn't. CallEvent automatically accounts for that (see getAdjustedParameterIndex() and getASTArgumentIndex() as they're overridden in various sub-classes of CallEvent).

427–441

Pls eventually transform this into CallDescriptionMap ^.^

554

You might want to cast Call to CXXMemberOperatorCall but i'm not sure it saves you anything.

[Szelethus]

Hmm, have you branched off of D71524? If so, this patch should definitely land first.

clang/lib/StaticAnalyzer/Checkers/GenericTaintChecker.cpp

158

Nice!

358

I have some thoughts about this here: D71524#1859435.

[steakhal]

Rebased on top of master, instead of D71524.

[Szelethus]

Wow. Its a joy to see you do C++. LGTM. Are you planning to introduce CallDescriptionMap at one point? :)

clang/lib/StaticAnalyzer/Checkers/GenericTaintChecker.cpp

492–510

Whoa, this is amazing, but looks like a google interview question or something -- is this a technique I should know about it? I feel like we kinda sacrificed readability for coolness.

[steakhal]

In D72035#1889320, @Szelethus wrote:

Wow. Its a joy to see you do C++. LGTM. Are you planning to introduce CallDescriptionMap at one point? :)

Yes, definitely.

clang/lib/StaticAnalyzer/Checkers/GenericTaintChecker.cpp

492–510

Actually, I agree but still convinced that it is the future-compatible way of doing this.

const auto OneOf = [FDecl](const auto &... Name) {
  // FIXME: use fold expression in C++17
  using unused = int[];
  bool ret = false;
  static_cast<void>(unused{
      0, (ret |= CheckerContext::isCLibraryFunction(FDecl, Name), 0)...});
  return ret;
};

In C++17 using fold expressions the whole lambda could be implemented such a way:

const auto OneOf = [FDecl](const auto &... Name) {
  return (CheckerContext::isCLibraryFunction(FDecl, Name) || ...);
};

[NoQ]

clang/lib/StaticAnalyzer/Checkers/GenericTaintChecker.cpp

113

rG878194414107e94600de31a11be09a347fb2598b!

[steakhal]

clang/lib/StaticAnalyzer/Checkers/GenericTaintChecker.cpp

113

Nice catch! Thank you for the fix.

clang/lib/StaticAnalyzer/Checkers/GenericTaintChecker.cpp

 #include "Taint.h"
 #include "Yaml.h"
 #include "clang/AST/Attr.h"
 #include "clang/Basic/Builtins.h"
 #include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
 #include "clang/StaticAnalyzer/Core/Checker.h"
 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
 #include "llvm/Support/YAMLTraits.h"
+
 #include <algorithm>
 #include <limits>
+#include <memory>
 #include <unordered_map>
 #include <utility>
 
 using namespace clang;
 using namespace ento;
 using namespace taint;
 
 namespace {
-class GenericTaintChecker
-    : public Checker<check::PostStmt<CallExpr>, check::PreStmt<CallExpr>> {
+class GenericTaintChecker : public Checker<check::PreCall, check::PostCall> {
 public:
   static void *getTag() {
     static int Tag;
     return &Tag;
   }
 
-  void checkPostStmt(const CallExpr *CE, CheckerContext &C) const;
-
-  void checkPreStmt(const CallExpr *CE, CheckerContext &C) const;
+  void checkPreCall(const CallEvent &Call, CheckerContext &C) const;
+  void checkPostCall(const CallEvent &Call, CheckerContext &C) const;
 
   void printState(raw_ostream &Out, ProgramStateRef State, const char *NL,
                   const char *Sep) const override;
 
   using ArgVector = SmallVector<unsigned, 2>;
   using SignedArgVector = SmallVector<int, 2>;
 
   enum class VariadicType { None, Src, Dst };
struct TaintConfiguration {
     TaintConfiguration(const TaintConfiguration &) = default;
     TaintConfiguration(TaintConfiguration &&) = default;
     TaintConfiguration &operator=(const TaintConfiguration &) = default;
     TaintConfiguration &operator=(TaintConfiguration &&) = default;
   };
 
   /// Convert SignedArgVector to ArgVector.
   ArgVector convertToArgVector(CheckerManager &Mgr, const std::string &Option,
-                               SignedArgVector Args);
+                               const SignedArgVector &Args);
 
   /// Parse the config.
   void parseConfiguration(CheckerManager &Mgr, const std::string &Option,
                           TaintConfiguration &&Config);
 
   static const unsigned InvalidArgIndex{std::numeric_limits<unsigned>::max()};
   /// Denotes the return vale.
   static const unsigned ReturnValueIndex{std::numeric_limits<unsigned>::max() -
                                          1};
 
 private:
   mutable std::unique_ptr<BugType> BT;
   void initBugType() const {
     if (!BT)
-      BT.reset(new BugType(this, "Use of Untrusted Data", "Untrusted Data"));
+      BT = std::make_unique<BugType>(this, "Use of Untrusted Data",
+                                     "Untrusted Data");
   }
 
   struct FunctionData {
     FunctionData() = delete;
     FunctionData(const FunctionData &) = default;
     FunctionData(FunctionData &&) = default;
     FunctionData &operator=(const FunctionData &) = delete;
     FunctionData &operator=(FunctionData &&) = delete;
 
-    static Optional<FunctionData> create(const CallExpr *CE,
+    static Optional<FunctionData> create(const CallEvent &Call,
                                          const CheckerContext &C) {
-      const FunctionDecl *FDecl = C.getCalleeDecl(CE);
+      assert(Call.getDecl());
+      const FunctionDecl *FDecl = Call.getDecl()->getAsFunction();
       if (!FDecl || (FDecl->getKind() != Decl::Function &&
                      FDecl->getKind() != Decl::CXXMethod))
         return None;
 
       StringRef Name = C.getCalleeName(FDecl);
       std::string FullName = FDecl->getQualifiedNameAsString();
       if (Name.empty() || FullName.empty())
         return None;
 
       return FunctionData{FDecl, Name, FullName};
     }
 
     bool isInScope(StringRef Scope) const {
       return StringRef(FullName).startswith(Scope);
     }
 
     const FunctionDecl *const FDecl;
     const StringRef Name;
     const std::string FullName;
   };
 
   /// Catch taint related bugs. Check if tainted data is passed to a
   /// system call etc. Returns true on matching.
-  bool checkPre(const CallExpr *CE, const FunctionData &FData,
+  bool checkPre(const CallEvent &Call, const FunctionData &FData,
                 CheckerContext &C) const;
 
   /// Add taint sources on a pre-visit. Returns true on matching.
-  bool addSourcesPre(const CallExpr *CE, const FunctionData &FData,
+  bool addSourcesPre(const CallEvent &Call, const FunctionData &FData,
                      CheckerContext &C) const;
 
   /// Mark filter's arguments not tainted on a pre-visit. Returns true on
   /// matching.
-  bool addFiltersPre(const CallExpr *CE, const FunctionData &FData,
+  bool addFiltersPre(const CallEvent &Call, const FunctionData &FData,
                      CheckerContext &C) const;
 
   /// Propagate taint generated at pre-visit. Returns true on matching.
-  bool propagateFromPre(const CallExpr *CE, CheckerContext &C) const;
+  static bool propagateFromPre(const CallEvent &Call, CheckerContext &C);
 
   /// Check if the region the expression evaluates to is the standard input,
   /// and thus, is tainted.
   static bool isStdin(const Expr *E, CheckerContext &C);
 
   /// Given a pointer argument, return the value it points to.
-  static Optional<SVal> getPointedToSVal(CheckerContext &C, const Expr *Arg);
+  static Optional<SVal> getPointeeOf(CheckerContext &C, const Expr *Arg);
 
   /// Check for CWE-134: Uncontrolled Format String.
   static constexpr llvm::StringLiteral MsgUncontrolledFormatString =
       "Untrusted data is used as a format string "
       "(CWE-134: Uncontrolled Format String)";
-  bool checkUncontrolledFormatString(const CallExpr *CE,
+  bool checkUncontrolledFormatString(const CallEvent &Call,
                                      CheckerContext &C) const;
 
   /// Check for:
   /// CERT/STR02-C. "Sanitize data passed to complex subsystems"
   /// CWE-78, "Failure to Sanitize Data into an OS Command"
   static constexpr llvm::StringLiteral MsgSanitizeSystemArgs =
       "Untrusted data is passed to a system call "
       "(CERT/STR02-C. Sanitize data passed to complex subsystems)";
-  bool checkSystemCall(const CallExpr *CE, StringRef Name,
+  bool checkSystemCall(const CallEvent &Call, StringRef Name,
                        CheckerContext &C) const;
 
   /// Check if tainted data is used as a buffer size ins strn.. functions,
   /// and allocators.
   static constexpr llvm::StringLiteral MsgTaintedBufferSize =
       "Untrusted data is used to specify the buffer size "
       "(CERT/STR31-C. Guarantee that storage for strings has sufficient space "
       "for character data and the null terminator)";
-  bool checkTaintedBufferSize(const CallExpr *CE, const FunctionDecl *FDecl,
-                              CheckerContext &C) const;
+  bool checkTaintedBufferSize(const CallEvent &Call, CheckerContext &C) const;
 
   /// Check if tainted data is used as a custom sink's parameter.
   static constexpr llvm::StringLiteral MsgCustomSink =
       "Untrusted data is passed to a user-defined sink";
-  bool checkCustomSinks(const CallExpr *CE, const FunctionData &FData,
+  bool checkCustomSinks(const CallEvent &Call, const FunctionData &FData,
                         CheckerContext &C) const;
 
   /// Generate a report if the expression is tainted or points to tainted data.
   bool generateReportIfTainted(const Expr *E, StringRef Msg,
                                CheckerContext &C) const;
 
   struct TaintPropagationRule;
   template <typename T>
private:
   /// If any of the possible taint source arguments is tainted, all of the
   /// destination arguments should also be tainted. Use InvalidArgIndex in the
   /// src list to specify that all of the arguments can introduce taint. Use
   /// InvalidArgIndex in the dst arguments to signify that all the non-const
   /// pointer and reference arguments might be tainted on return. If
   /// ReturnValueIndex is added to the dst list, the return value will be
   /// tainted.
   struct TaintPropagationRule {
-    using PropagationFuncType = bool (*)(bool IsTainted, const CallExpr *,
+    using PropagationFuncType = bool (*)(bool IsTainted, const CallEvent &Call,
                                          CheckerContext &C);
 
     /// List of arguments which can be taint sources and should be checked.
     ArgVector SrcArgs;
     /// List of arguments which should be tainted on function return.
     ArgVector DstArgs;
     /// Index for the first variadic parameter if exist.
     unsigned VariadicIndex;
bool isNull() const {
       return SrcArgs.empty() && DstArgs.empty() &&
              VariadicType::None == VarType;
     }
 
     bool isDestinationArgument(unsigned ArgNum) const {
       return (llvm::find(DstArgs, ArgNum) != DstArgs.end());
     }
 
-    static bool isTaintedOrPointsToTainted(const Expr *E, ProgramStateRef State,
+    static bool isTaintedOrPointsToTainted(const Expr *E,
+                                           const ProgramStateRef &State,
                                            CheckerContext &C) {
       if (isTainted(State, E, C.getLocationContext()) || isStdin(E, C))
         return true;
 
       if (!E->getType().getTypePtr()->isPointerType())
         return false;
 
-      Optional<SVal> V = getPointedToSVal(C, E);
+      Optional<SVal> V = getPointeeOf(C, E);
       return (V && isTainted(State, *V));
     }
 
     /// Pre-process a function which propagates taint according to the
     /// taint rule.
-    ProgramStateRef process(const CallExpr *CE, CheckerContext &C) const;
+    ProgramStateRef process(const CallEvent &Call, CheckerContext &C) const;
 
     // Functions for custom taintedness propagation.
-    static bool postSocket(bool IsTainted, const CallExpr *CE,
+    static bool postSocket(bool IsTainted, const CallEvent &Call,
                            CheckerContext &C);
   };
 
   /// Defines a map between the propagation function's name, scope
   /// and TaintPropagationRule.
   NameRuleMap CustomPropagations;
 
   /// Defines a map between the filter function's name, scope and filtering

 } // namespace llvm
 
 /// A set which is used to pass information from call pre-visit instruction
 /// to the call post-visit. The values are unsigned integers, which are either
 /// ReturnValueIndex, or indexes of the pointer/reference argument, which
 /// points to data, which should be tainted on return.
 REGISTER_SET_WITH_PROGRAMSTATE(TaintArgsOnPostVisit, unsigned)
 
-GenericTaintChecker::ArgVector GenericTaintChecker::convertToArgVector(
-    CheckerManager &Mgr, const std::string &Option, SignedArgVector Args) {
+GenericTaintChecker::ArgVector
+GenericTaintChecker::convertToArgVector(CheckerManager &Mgr,
+                                        const std::string &Option,
+                                        const SignedArgVector &Args) {
   ArgVector Result;
   for (int Arg : Args) {
     if (Arg == -1)
       Result.push_back(ReturnValueIndex);
     else if (Arg < -1) {
       Result.push_back(InvalidArgIndex);
       Mgr.reportInvalidCheckerOptionValue(
           this, Option,
GenericTaintChecker::TaintPropagationRule::getTaintPropagationRule(
   // value as tainted even if it's just a pointer, pointing to tainted data.
 
   // Check for exact name match for functions without builtin substitutes.
   // Use qualified name, because these are C functions without namespace.
   TaintPropagationRule Rule =
       llvm::StringSwitch<TaintPropagationRule>(FData.FullName)
           // Source functions
           // TODO: Add support for vfscanf & family.
-          .Case("fdopen", TaintPropagationRule({}, {ReturnValueIndex}))
-          .Case("fopen", TaintPropagationRule({}, {ReturnValueIndex}))
-          .Case("freopen", TaintPropagationRule({}, {ReturnValueIndex}))
-          .Case("getch", TaintPropagationRule({}, {ReturnValueIndex}))
-          .Case("getchar", TaintPropagationRule({}, {ReturnValueIndex}))
-          .Case("getchar_unlocked",
-                TaintPropagationRule({}, {ReturnValueIndex}))
-          .Case("getenv", TaintPropagationRule({}, {ReturnValueIndex}))
-          .Case("gets", TaintPropagationRule({}, {0, ReturnValueIndex}))
-          .Case("scanf", TaintPropagationRule({}, {}, VariadicType::Dst, 1))
-          .Case("socket",
-                TaintPropagationRule({}, {ReturnValueIndex}, VariadicType::None,
-                                     InvalidArgIndex,
-                                     &TaintPropagationRule::postSocket))
-          .Case("wgetch", TaintPropagationRule({}, {ReturnValueIndex}))
+          .Case("fdopen", {{}, {ReturnValueIndex}})
+          .Case("fopen", {{}, {ReturnValueIndex}})
+          .Case("freopen", {{}, {ReturnValueIndex}})
+          .Case("getch", {{}, {ReturnValueIndex}})
+          .Case("getchar", {{}, {ReturnValueIndex}})
+          .Case("getchar_unlocked", {{}, {ReturnValueIndex}})
+          .Case("getenv", {{}, {ReturnValueIndex}})
+          .Case("gets", {{}, {0, ReturnValueIndex}})
+          .Case("scanf", {{}, {}, VariadicType::Dst, 1})
+          .Case("socket", {{},
+                           {ReturnValueIndex},
+                           VariadicType::None,
+                           &TaintPropagationRule::postSocket})
+          .Case("wgetch", {{}, {ReturnValueIndex}})
           // Propagating functions
-          .Case("atoi", TaintPropagationRule({0}, {ReturnValueIndex}))
-          .Case("atol", TaintPropagationRule({0}, {ReturnValueIndex}))
-          .Case("atoll", TaintPropagationRule({0}, {ReturnValueIndex}))
-          .Case("fgetc", TaintPropagationRule({0}, {ReturnValueIndex}))
-          .Case("fgetln", TaintPropagationRule({0}, {ReturnValueIndex}))
-          .Case("fgets", TaintPropagationRule({2}, {0, ReturnValueIndex}))
-          .Case("fscanf", TaintPropagationRule({0}, {}, VariadicType::Dst, 2))
-          .Case("getc", TaintPropagationRule({0}, {ReturnValueIndex}))
-          .Case("getc_unlocked", TaintPropagationRule({0}, {ReturnValueIndex}))
-          .Case("getdelim", TaintPropagationRule({3}, {0}))
-          .Case("getline", TaintPropagationRule({2}, {0}))
-          .Case("getw", TaintPropagationRule({0}, {ReturnValueIndex}))
-          .Case("pread",
-                TaintPropagationRule({0, 1, 2, 3}, {1, ReturnValueIndex}))
-          .Case("read", TaintPropagationRule({0, 2}, {1, ReturnValueIndex}))
-          .Case("strchr", TaintPropagationRule({0}, {ReturnValueIndex}))
-          .Case("strrchr", TaintPropagationRule({0}, {ReturnValueIndex}))
-          .Case("tolower", TaintPropagationRule({0}, {ReturnValueIndex}))
-          .Case("toupper", TaintPropagationRule({0}, {ReturnValueIndex}))
-          .Default(TaintPropagationRule());
+          .Case("atoi", {{0}, {ReturnValueIndex}})
+          .Case("atol", {{0}, {ReturnValueIndex}})
+          .Case("atoll", {{0}, {ReturnValueIndex}})
+          .Case("fgetc", {{0}, {ReturnValueIndex}})
+          .Case("fgetln", {{0}, {ReturnValueIndex}})
+          .Case("fgets", {{2}, {0, ReturnValueIndex}})
+          .Case("fscanf", {{0}, {}, VariadicType::Dst, 2})
+          .Case("sscanf", {{0}, {}, VariadicType::Dst, 2})
+          .Case("getc", {{0}, {ReturnValueIndex}})
+          .Case("getc_unlocked", {{0}, {ReturnValueIndex}})
+          .Case("getdelim", {{3}, {0}})
+          .Case("getline", {{2}, {0}})
+          .Case("getw", {{0}, {ReturnValueIndex}})
+          .Case("pread", {{0, 1, 2, 3}, {1, ReturnValueIndex}})
+          .Case("read", {{0, 2}, {1, ReturnValueIndex}})
+          .Case("strchr", {{0}, {ReturnValueIndex}})
+          .Case("strrchr", {{0}, {ReturnValueIndex}})
+          .Case("tolower", {{0}, {ReturnValueIndex}})
+          .Case("toupper", {{0}, {ReturnValueIndex}})
+          .Default({});
 
   if (!Rule.isNull())
     return Rule;
+  assert(FData.FDecl);
 
   // Check if it's one of the memory setting/copying functions.
   // This check is specialized but faster then calling isCLibraryFunction.
   const FunctionDecl *FDecl = FData.FDecl;
   unsigned BId = 0;
-  if ((BId = FDecl->getMemoryFunctionKind()))
+  if ((BId = FDecl->getMemoryFunctionKind())) {
     switch (BId) {
     case Builtin::BImemcpy:
     case Builtin::BImemmove:
     case Builtin::BIstrncpy:
     case Builtin::BIstrncat:
-      return TaintPropagationRule({1, 2}, {0, ReturnValueIndex});
+      return {{1, 2}, {0, ReturnValueIndex}};
     case Builtin::BIstrlcpy:
     case Builtin::BIstrlcat:
-      return TaintPropagationRule({1, 2}, {0});
+      return {{1, 2}, {0}};
     case Builtin::BIstrndup:
-      return TaintPropagationRule({0, 1}, {ReturnValueIndex});
+      return {{0, 1}, {ReturnValueIndex}};
 
     default:
       break;
-    };
+    }
+  }
 
   // Process all other functions which could be defined as builtins.
   if (Rule.isNull()) {
-    if (C.isCLibraryFunction(FDecl, "snprintf"))
-      return TaintPropagationRule({1}, {0, ReturnValueIndex}, VariadicType::Src,
-                                  3);
-    else if (C.isCLibraryFunction(FDecl, "sprintf"))
-      return TaintPropagationRule({}, {0, ReturnValueIndex}, VariadicType::Src,
-                                  2);
-    else if (C.isCLibraryFunction(FDecl, "strcpy") ||
-             C.isCLibraryFunction(FDecl, "stpcpy") ||
-             C.isCLibraryFunction(FDecl, "strcat"))
-      return TaintPropagationRule({1}, {0, ReturnValueIndex});
-    else if (C.isCLibraryFunction(FDecl, "bcopy"))
-      return TaintPropagationRule({0, 2}, {1});
-    else if (C.isCLibraryFunction(FDecl, "strdup") ||
-             C.isCLibraryFunction(FDecl, "strdupa"))
-      return TaintPropagationRule({0}, {ReturnValueIndex});
-    else if (C.isCLibraryFunction(FDecl, "wcsdup"))
-      return TaintPropagationRule({0}, {ReturnValueIndex});
+    const auto OneOf = [FDecl](const auto &... Name) {
+      // FIXME: use fold expression in C++17
+      using unused = int[];
+      bool ret = false;
+      static_cast<void>(unused{
+          0, (ret |= CheckerContext::isCLibraryFunction(FDecl, Name), 0)...});
+      return ret;
+    };
+    if (OneOf("snprintf"))
+      return {{1}, {0, ReturnValueIndex}, VariadicType::Src, 3};
+    if (OneOf("sprintf"))
+      return {{}, {0, ReturnValueIndex}, VariadicType::Src, 2};
+    if (OneOf("strcpy", "stpcpy", "strcat"))
+      return {{1}, {0, ReturnValueIndex}};
+    if (OneOf("bcopy"))
+      return {{0, 2}, {1}};
+    if (OneOf("strdup", "strdupa", "wcsdup"))
+      return {{0}, {ReturnValueIndex}};
   }
 
-  // Skipping the following functions, since they might be used for cleansing
-  // or smart memory copy:
+  // Skipping the following functions, since they might be used for cleansing or
+  // smart memory copy:
   // - memccpy - copying until hitting a special character.
 
   auto It = findFunctionInConfig(CustomPropagations, FData);
-  if (It != CustomPropagations.end()) {
-    const auto &Value = It->second;
-    return Value.second;
-  }
+  if (It != CustomPropagations.end())
+    return It->second.second;
+  return {};
 
-  return TaintPropagationRule();
-}
-
-void GenericTaintChecker::checkPreStmt(const CallExpr *CE,
+void GenericTaintChecker::checkPreCall(const CallEvent &Call,
                                        CheckerContext &C) const {
-  Optional<FunctionData> FData = FunctionData::create(CE, C);
+  Optional<FunctionData> FData = FunctionData::create(Call, C);
   if (!FData)
     return;
 
   // Check for taintedness related errors first: system call, uncontrolled
   // format string, tainted buffer size.
-  if (checkPre(CE, *FData, C))
+  if (checkPre(Call, *FData, C))
     return;
 
   // Marks the function's arguments and/or return value tainted if it present in
   // the list.
-  if (addSourcesPre(CE, *FData, C))
+  if (addSourcesPre(Call, *FData, C))
     return;
 
-  addFiltersPre(CE, *FData, C);
+  addFiltersPre(Call, *FData, C);
 }
 
-void GenericTaintChecker::checkPostStmt(const CallExpr *CE,
+void GenericTaintChecker::checkPostCall(const CallEvent &Call,
                                         CheckerContext &C) const {
   // Set the marked values as tainted. The return value only accessible from
   // checkPostStmt.
-  propagateFromPre(CE, C);
+  propagateFromPre(Call, C);
 }
 
 void GenericTaintChecker::printState(raw_ostream &Out, ProgramStateRef State,
                                      const char *NL, const char *Sep) const {
   printTaint(State, Out, NL, Sep);
 }
 
-bool GenericTaintChecker::addSourcesPre(const CallExpr *CE,
+bool GenericTaintChecker::addSourcesPre(const CallEvent &Call,
                                         const FunctionData &FData,
                                         CheckerContext &C) const {
   // First, try generating a propagation rule for this function.
   TaintPropagationRule Rule = TaintPropagationRule::getTaintPropagationRule(
       this->CustomPropagations, FData, C);
   if (!Rule.isNull()) {
-    ProgramStateRef State = Rule.process(CE, C);
+    ProgramStateRef State = Rule.process(Call, C);
     if (State) {
       C.addTransition(State);
       return true;
     }
   }
   return false;
 }
 
-bool GenericTaintChecker::addFiltersPre(const CallExpr *CE,
+bool GenericTaintChecker::addFiltersPre(const CallEvent &Call,
                                         const FunctionData &FData,
                                         CheckerContext &C) const {
   auto It = findFunctionInConfig(CustomFilters, FData);
   if (It == CustomFilters.end())
     return false;
 
   ProgramStateRef State = C.getState();
   const auto &Value = It->second;
   const ArgVector &Args = Value.second;
   for (unsigned ArgNum : Args) {
-    if (ArgNum >= CE->getNumArgs())
+    if (ArgNum >= Call.getNumArgs())
       continue;
 
-    const Expr *Arg = CE->getArg(ArgNum);
-    Optional<SVal> V = getPointedToSVal(C, Arg);
+    const Expr *Arg = Call.getArgExpr(ArgNum);
+    Optional<SVal> V = getPointeeOf(C, Arg);
     if (V)
       State = removeTaint(State, *V);
   }
 
   if (State != C.getState()) {
     C.addTransition(State);
     return true;
   }
   return false;
 }
 
-bool GenericTaintChecker::propagateFromPre(const CallExpr *CE,
-                                           CheckerContext &C) const {
+bool GenericTaintChecker::propagateFromPre(const CallEvent &Call,
+                                           CheckerContext &C) {
   ProgramStateRef State = C.getState();
 
   // Depending on what was tainted at pre-visit, we determined a set of
   // arguments which should be tainted after the function returns. These are
   // stored in the state as TaintArgsOnPostVisit set.
   TaintArgsOnPostVisitTy TaintArgs = State->get<TaintArgsOnPostVisit>();
   if (TaintArgs.isEmpty())
     return false;
 
   for (unsigned ArgNum : TaintArgs) {
     // Special handling for the tainted return value.
     if (ArgNum == ReturnValueIndex) {
-      State = addTaint(State, CE, C.getLocationContext());
+      State = addTaint(State, Call.getReturnValue());
       continue;
     }
 
     // The arguments are pointer arguments. The data they are pointing at is
     // tainted after the call.
-    if (CE->getNumArgs() < (ArgNum + 1))
+    if (Call.getNumArgs() < (ArgNum + 1))
       return false;
-    const Expr *Arg = CE->getArg(ArgNum);
-    Optional<SVal> V = getPointedToSVal(C, Arg);
+    const Expr *Arg = Call.getArgExpr(ArgNum);
+    Optional<SVal> V = getPointeeOf(C, Arg);
     if (V)
       State = addTaint(State, *V);
   }
 
   // Clear up the taint info from the state.
   State = State->remove<TaintArgsOnPostVisit>();
 
   if (State != C.getState()) {
     C.addTransition(State);
     return true;
   }
   return false;
 }
 
-bool GenericTaintChecker::checkPre(const CallExpr *CE,
+bool GenericTaintChecker::checkPre(const CallEvent &Call,
                                    const FunctionData &FData,
                                    CheckerContext &C) const {
-
-  if (checkUncontrolledFormatString(CE, C))
-    return true;
-
-  if (checkSystemCall(CE, FData.Name, C))
+  if (checkUncontrolledFormatString(Call, C))
     return true;
 
-  if (checkTaintedBufferSize(CE, FData.FDecl, C))
+  if (checkSystemCall(Call, FData.Name, C))
     return true;
 
-  if (checkCustomSinks(CE, FData, C))
+  if (checkTaintedBufferSize(Call, C))
     return true;
 
-  return false;
+  return checkCustomSinks(Call, FData, C);
 }
 
-Optional<SVal> GenericTaintChecker::getPointedToSVal(CheckerContext &C,
-                                                     const Expr *Arg) {
+Optional<SVal> GenericTaintChecker::getPointeeOf(CheckerContext &C,
   ProgramStateRef State = C.getState();
   SVal AddrVal = C.getSVal(Arg->IgnoreParens());
   if (AddrVal.isUnknownOrUndef())
     return None;
 
   Optional<Loc> AddrLoc = AddrVal.getAs<Loc>();
   if (!AddrLoc)
     return None;
 
   QualType ArgTy = Arg->getType().getCanonicalType();
   if (!ArgTy->isPointerType())
     return State->getSVal(*AddrLoc);
 
   QualType ValTy = ArgTy->getPointeeType();
 
   // Do not dereference void pointers. Treat them as byte pointers instead.
   // FIXME: we might want to consider more than just the first byte.
   if (ValTy->isVoidType())
     ValTy = C.getASTContext().CharTy;
 
   return State->getSVal(*AddrLoc, ValTy);
 }
 
 ProgramStateRef
-GenericTaintChecker::TaintPropagationRule::process(const CallExpr *CE,
+GenericTaintChecker::TaintPropagationRule::process(const CallEvent &Call,
                                                    CheckerContext &C) const {
   ProgramStateRef State = C.getState();
 
   // Check for taint in arguments.
   bool IsTainted = true;
   for (unsigned ArgNum : SrcArgs) {
-    if (ArgNum >= CE->getNumArgs())
+    if (ArgNum >= Call.getNumArgs())
       continue;
 
-    if ((IsTainted = isTaintedOrPointsToTainted(CE->getArg(ArgNum), State, C)))
+    if ((IsTainted =
+             isTaintedOrPointsToTainted(Call.getArgExpr(ArgNum), State, C)))
       break;
   }
 
   // Check for taint in variadic arguments.
   if (!IsTainted && VariadicType::Src == VarType) {
     // Check if any of the arguments is tainted
-    for (unsigned i = VariadicIndex; i < CE->getNumArgs(); ++i) {
-      if ((IsTainted = isTaintedOrPointsToTainted(CE->getArg(i), State, C)))
+    for (unsigned i = VariadicIndex; i < Call.getNumArgs(); ++i) {
+      if ((IsTainted =
+               isTaintedOrPointsToTainted(Call.getArgExpr(i), State, C)))
         break;
     }
   }
 
   if (PropagationFunc)
-    IsTainted = PropagationFunc(IsTainted, CE, C);
+    IsTainted = PropagationFunc(IsTainted, Call, C);
 
   if (!IsTainted)
     return State;
 
   // Mark the arguments which should be tainted after the function returns.
   for (unsigned ArgNum : DstArgs) {
     // Should mark the return value?
     if (ArgNum == ReturnValueIndex) {
       State = State->add<TaintArgsOnPostVisit>(ReturnValueIndex);
       continue;
     }
 
-    if (ArgNum >= CE->getNumArgs())
+    if (ArgNum >= Call.getNumArgs())
       continue;
 
     // Mark the given argument.
     State = State->add<TaintArgsOnPostVisit>(ArgNum);
   }
 
   // Mark all variadic arguments tainted if present.
   if (VariadicType::Dst == VarType) {
     // For all pointer and references that were passed in:
     //   If they are not pointing to const data, mark data as tainted.
     //   TODO: So far we are just going one level down; ideally we'd need to
     //         recurse here.
-    for (unsigned i = VariadicIndex; i < CE->getNumArgs(); ++i) {
-      const Expr *Arg = CE->getArg(i);
+    for (unsigned i = VariadicIndex; i < Call.getNumArgs(); ++i) {
+      const Expr *Arg = Call.getArgExpr(i);
       // Process pointer argument.
       const Type *ArgTy = Arg->getType().getTypePtr();
       QualType PType = ArgTy->getPointeeType();
       if ((!PType.isNull() && !PType.isConstQualified()) ||
-          (ArgTy->isReferenceType() && !Arg->getType().isConstQualified()))
+          (ArgTy->isReferenceType() && !Arg->getType().isConstQualified())) {
         State = State->add<TaintArgsOnPostVisit>(i);
       }
     }
+  }
 
   return State;
 }
 
 // If argument 0(protocol domain) is network, the return value should get taint.
-bool GenericTaintChecker::TaintPropagationRule::postSocket(bool /*IsTainted*/,
-                                                           const CallExpr *CE,
-                                                           CheckerContext &C) {
-  SourceLocation DomLoc = CE->getArg(0)->getExprLoc();
+bool GenericTaintChecker::TaintPropagationRule::postSocket(
+    bool /*IsTainted*/, const CallEvent &Call, CheckerContext &C) {
+  SourceLocation DomLoc = Call.getArgExpr(0)->getExprLoc();
   StringRef DomName = C.getMacroNameOrSpelling(DomLoc);
   // White list the internal communication protocols.
   if (DomName.equals("AF_SYSTEM") || DomName.equals("AF_LOCAL") ||
       DomName.equals("AF_UNIX") || DomName.equals("AF_RESERVED_36"))
     return false;
-
   return true;
 }
 
 bool GenericTaintChecker::isStdin(const Expr *E, CheckerContext &C) {
   ProgramStateRef State = C.getState();
   SVal Val = C.getSVal(E);
 
   // stdin is a pointer, so it would be a region.
   const MemRegion *MemReg = Val.getAsRegion();
 
   // The region should be symbolic, we do not know it's value.
-  const SymbolicRegion *SymReg = dyn_cast_or_null<SymbolicRegion>(MemReg);
+  const auto *SymReg = dyn_cast_or_null<SymbolicRegion>(MemReg);
   if (!SymReg)
     return false;
 
   // Get it's symbol and find the declaration region it's pointing to.
-  const SymbolRegionValue *Sm =
-      dyn_cast<SymbolRegionValue>(SymReg->getSymbol());
+  const auto *Sm = dyn_cast<SymbolRegionValue>(SymReg->getSymbol());
   if (!Sm)
     return false;
-  const DeclRegion *DeclReg = dyn_cast_or_null<DeclRegion>(Sm->getRegion());
+  const auto *DeclReg = dyn_cast_or_null<DeclRegion>(Sm->getRegion());
   if (!DeclReg)
     return false;
 
   // This region corresponds to a declaration, find out if it's a global/extern
   // variable named stdin with the proper type.
   if (const auto *D = dyn_cast_or_null<VarDecl>(DeclReg->getDecl())) {
     D = D->getCanonicalDecl();
     if ((D->getName().find("stdin") != StringRef::npos) && D->isExternC()) {
       const auto *PtrTy = dyn_cast<PointerType>(D->getType().getTypePtr());
       if (PtrTy && PtrTy->getPointeeType().getCanonicalType() ==
                        C.getASTContext().getFILEType().getCanonicalType())
         return true;
     }
   }
   return false;
 }
 
-static bool getPrintfFormatArgumentNum(const CallExpr *CE,
+static bool getPrintfFormatArgumentNum(const CallEvent &Call,
                                        const CheckerContext &C,
                                        unsigned &ArgNum) {
   // Find if the function contains a format string argument.
   // Handles: fprintf, printf, sprintf, snprintf, vfprintf, vprintf, vsprintf,
   // vsnprintf, syslog, custom annotated functions.
-  const FunctionDecl *FDecl = C.getCalleeDecl(CE);
+  const FunctionDecl *FDecl = Call.getDecl()->getAsFunction();
   if (!FDecl)
     return false;
   for (const auto *Format : FDecl->specific_attrs<FormatAttr>()) {
     ArgNum = Format->getFormatIdx() - 1;
-    if ((Format->getType()->getName() == "printf") && CE->getNumArgs() > ArgNum)
+    if ((Format->getType()->getName() == "printf") &&
+        Call.getNumArgs() > ArgNum)
       return true;
   }
 
   // Or if a function is named setproctitle (this is a heuristic).
-  if (C.getCalleeName(CE).find("setproctitle") != StringRef::npos) {
+  if (C.getCalleeName(FDecl).find("setproctitle") != StringRef::npos) {
     ArgNum = 0;
     return true;
   }
 
   return false;
 }
 
 bool GenericTaintChecker::generateReportIfTainted(const Expr *E, StringRef Msg,
                                                   CheckerContext &C) const {
   assert(E);
 
   // Check for taint.
   ProgramStateRef State = C.getState();
-  Optional<SVal> PointedToSVal = getPointedToSVal(C, E);
+  Optional<SVal> PointedToSVal = getPointeeOf(C, E);
   SVal TaintedSVal;
   if (PointedToSVal && isTainted(State, *PointedToSVal))
     TaintedSVal = *PointedToSVal;
   else if (isTainted(State, E, C.getLocationContext()))
     TaintedSVal = C.getSVal(E);
   else
     return false;
 
   // Generate diagnostic.
   if (ExplodedNode *N = C.generateNonFatalErrorNode()) {
     initBugType();
     auto report = std::make_unique<PathSensitiveBugReport>(*BT, Msg, N);
     report->addRange(E->getSourceRange());
     report->addVisitor(std::make_unique<TaintBugVisitor>(TaintedSVal));
     C.emitReport(std::move(report));
     return true;
   }
   return false;
 }
 
 bool GenericTaintChecker::checkUncontrolledFormatString(
-    const CallExpr *CE, CheckerContext &C) const {
+    const CallEvent &Call, CheckerContext &C) const {
   // Check if the function contains a format string argument.
   unsigned ArgNum = 0;
-  if (!getPrintfFormatArgumentNum(CE, C, ArgNum))
+  if (!getPrintfFormatArgumentNum(Call, C, ArgNum))
     return false;
 
   // If either the format string content or the pointer itself are tainted,
   // warn.
-  return generateReportIfTainted(CE->getArg(ArgNum),
+  return generateReportIfTainted(Call.getArgExpr(ArgNum),
                                  MsgUncontrolledFormatString, C);
 }
 
-bool GenericTaintChecker::checkSystemCall(const CallExpr *CE, StringRef Name,
+bool GenericTaintChecker::checkSystemCall(const CallEvent &Call, StringRef Name,
                                           CheckerContext &C) const {
   // TODO: It might make sense to run this check on demand. In some cases,
   // we should check if the environment has been cleansed here. We also might
   // need to know if the user was reset before these calls(seteuid).
   unsigned ArgNum = llvm::StringSwitch<unsigned>(Name)
                         .Case("system", 0)
                         .Case("popen", 0)
                         .Case("execl", 0)
                         .Case("execle", 0)
                         .Case("execlp", 0)
                         .Case("execv", 0)
                         .Case("execvp", 0)
                         .Case("execvP", 0)
                         .Case("execve", 0)
                         .Case("dlopen", 0)
                         .Default(InvalidArgIndex);
 
-  if (ArgNum == InvalidArgIndex || CE->getNumArgs() < (ArgNum + 1))
+  if (ArgNum == InvalidArgIndex || Call.getNumArgs() < (ArgNum + 1))
     return false;
 
-  return generateReportIfTainted(CE->getArg(ArgNum), MsgSanitizeSystemArgs, C);
+  return generateReportIfTainted(Call.getArgExpr(ArgNum), MsgSanitizeSystemArgs,
+                                 C);
 }
 
 // TODO: Should this check be a part of the CString checker?
 // If yes, should taint be a global setting?
-bool GenericTaintChecker::checkTaintedBufferSize(const CallExpr *CE,
-                                                 const FunctionDecl *FDecl,
+bool GenericTaintChecker::checkTaintedBufferSize(const CallEvent &Call,
                                                  CheckerContext &C) const {
+  const auto *FDecl = Call.getDecl()->getAsFunction();
   // If the function has a buffer size argument, set ArgNum.
   unsigned ArgNum = InvalidArgIndex;
   unsigned BId = 0;
-  if ((BId = FDecl->getMemoryFunctionKind()))
+  if ((BId = FDecl->getMemoryFunctionKind())) {
     switch (BId) {
     case Builtin::BImemcpy:
     case Builtin::BImemmove:
     case Builtin::BIstrncpy:
       ArgNum = 2;
       break;
     case Builtin::BIstrndup:
       ArgNum = 1;
       break;
     default:
       break;
-    };
+    }
+  }
 
   if (ArgNum == InvalidArgIndex) {
-    if (C.isCLibraryFunction(FDecl, "malloc") ||
-        C.isCLibraryFunction(FDecl, "calloc") ||
-        C.isCLibraryFunction(FDecl, "alloca"))
+    using CCtx = CheckerContext;
+    if (CCtx::isCLibraryFunction(FDecl, "malloc") ||
+        CCtx::isCLibraryFunction(FDecl, "calloc") ||
+        CCtx::isCLibraryFunction(FDecl, "alloca"))
       ArgNum = 0;
-    else if (C.isCLibraryFunction(FDecl, "memccpy"))
+    else if (CCtx::isCLibraryFunction(FDecl, "memccpy"))
       ArgNum = 3;
-    else if (C.isCLibraryFunction(FDecl, "realloc"))
+    else if (CCtx::isCLibraryFunction(FDecl, "realloc"))
       ArgNum = 1;
-    else if (C.isCLibraryFunction(FDecl, "bcopy"))
+    else if (CCtx::isCLibraryFunction(FDecl, "bcopy"))
       ArgNum = 2;
   }
 
-  return ArgNum != InvalidArgIndex && CE->getNumArgs() > ArgNum &&
-         generateReportIfTainted(CE->getArg(ArgNum), MsgTaintedBufferSize, C);
+  return ArgNum != InvalidArgIndex && Call.getNumArgs() > ArgNum &&
+         generateReportIfTainted(Call.getArgExpr(ArgNum), MsgTaintedBufferSize,
+                                 C);
 }
 
-bool GenericTaintChecker::checkCustomSinks(const CallExpr *CE,
+bool GenericTaintChecker::checkCustomSinks(const CallEvent &Call,
                                            const FunctionData &FData,
                                            CheckerContext &C) const {
   auto It = findFunctionInConfig(CustomSinks, FData);
   if (It == CustomSinks.end())
     return false;
 
   const auto &Value = It->second;
   const GenericTaintChecker::ArgVector &Args = Value.second;
   for (unsigned ArgNum : Args) {
-    if (ArgNum >= CE->getNumArgs())
+    if (ArgNum >= Call.getNumArgs())
       continue;
 
-    if (generateReportIfTainted(CE->getArg(ArgNum), MsgCustomSink, C))
+    if (generateReportIfTainted(Call.getArgExpr(ArgNum), MsgCustomSink, C))
       return true;
   }
 
   return false;
 }
 
 void ento::registerGenericTaintChecker(CheckerManager &Mgr) {
   auto *Checker = Mgr.registerChecker<GenericTaintChecker>();