[analyzer] CastValueChecker: Model castAs(), getAs()
Summary: Thanks to Kristóf Umann for the great idea!
Reviewed By: NoQ
Differential Revision: https://reviews.llvm.org/D65889
llvm-svn: 368383
diff --git a/clang/lib/StaticAnalyzer/Checkers/CastValueChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/CastValueChecker.cpp
index ff5d12c..9cf1b0a 100644
--- a/clang/lib/StaticAnalyzer/Checkers/CastValueChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/CastValueChecker.cpp
@@ -16,168 +16,238 @@
#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
#include "llvm/ADT/Optional.h"
+#include <utility>
using namespace clang;
using namespace ento;
namespace {
class CastValueChecker : public Checker<eval::Call> {
+ enum class CastKind { Function, Method };
+
using CastCheck =
std::function<void(const CastValueChecker *, const CallExpr *,
DefinedOrUnknownSVal, CheckerContext &)>;
+ using CheckKindPair = std::pair<CastCheck, CastKind>;
+
public:
- // We have three cases to evaluate a cast:
+ // We have five cases to evaluate a cast:
// 1) The parameter is non-null, the return value is non-null
// 2) The parameter is non-null, the return value is null
// 3) The parameter is null, the return value is null
- //
// cast: 1; dyn_cast: 1, 2; cast_or_null: 1, 3; dyn_cast_or_null: 1, 2, 3.
+ //
+ // 4) castAs: has no parameter, the return value is non-null.
+ // 5) getAs: has no parameter, the return value is null or non-null.
bool evalCall(const CallEvent &Call, CheckerContext &C) const;
private:
- // These are known in the LLVM project.
- const CallDescriptionMap<CastCheck> CDM = {
- {{{"llvm", "cast"}, 1}, &CastValueChecker::evalCast},
- {{{"llvm", "dyn_cast"}, 1}, &CastValueChecker::evalDynCast},
- {{{"llvm", "cast_or_null"}, 1}, &CastValueChecker::evalCastOrNull},
+ // These are known in the LLVM project. The pairs are in the following form:
+ // {{{namespace, call}, argument-count}, {callback, kind}}
+ const CallDescriptionMap<CheckKindPair> CDM = {
+ {{{"llvm", "cast"}, 1},
+ {&CastValueChecker::evalCast, CastKind::Function}},
+ {{{"llvm", "dyn_cast"}, 1},
+ {&CastValueChecker::evalDynCast, CastKind::Function}},
+ {{{"llvm", "cast_or_null"}, 1},
+ {&CastValueChecker::evalCastOrNull, CastKind::Function}},
{{{"llvm", "dyn_cast_or_null"}, 1},
- &CastValueChecker::evalDynCastOrNull}};
+ {&CastValueChecker::evalDynCastOrNull, CastKind::Function}},
+ {{{"clang", "castAs"}, 0},
+ {&CastValueChecker::evalCastAs, CastKind::Method}},
+ {{{"clang", "getAs"}, 0},
+ {&CastValueChecker::evalGetAs, CastKind::Method}}};
- void evalCast(const CallExpr *CE, DefinedOrUnknownSVal ParamDV,
+ void evalCast(const CallExpr *CE, DefinedOrUnknownSVal DV,
CheckerContext &C) const;
- void evalDynCast(const CallExpr *CE, DefinedOrUnknownSVal ParamDV,
+ void evalDynCast(const CallExpr *CE, DefinedOrUnknownSVal DV,
CheckerContext &C) const;
- void evalCastOrNull(const CallExpr *CE, DefinedOrUnknownSVal ParamDV,
+ void evalCastOrNull(const CallExpr *CE, DefinedOrUnknownSVal DV,
CheckerContext &C) const;
- void evalDynCastOrNull(const CallExpr *CE, DefinedOrUnknownSVal ParamDV,
+ void evalDynCastOrNull(const CallExpr *CE, DefinedOrUnknownSVal DV,
CheckerContext &C) const;
+ void evalCastAs(const CallExpr *CE, DefinedOrUnknownSVal DV,
+ CheckerContext &C) const;
+ void evalGetAs(const CallExpr *CE, DefinedOrUnknownSVal DV,
+ CheckerContext &C) const;
};
} // namespace
static std::string getCastName(const Expr *Cast) {
- return Cast->getType()->getPointeeCXXRecordDecl()->getNameAsString();
+ QualType Ty = Cast->getType();
+ if (const CXXRecordDecl *RD = Ty->getAsCXXRecordDecl())
+ return RD->getNameAsString();
+
+ return Ty->getPointeeCXXRecordDecl()->getNameAsString();
}
-static void evalNonNullParamNonNullReturn(const CallExpr *CE,
- DefinedOrUnknownSVal ParamDV,
- CheckerContext &C) {
- ProgramStateRef State = C.getState()->assume(ParamDV, true);
- if (!State)
- return;
-
- State = State->BindExpr(CE, C.getLocationContext(), ParamDV, false);
-
- std::string CastFromName = getCastName(CE->getArg(0));
+static const NoteTag *getCastTag(bool IsNullReturn, const CallExpr *CE,
+ CheckerContext &C,
+ bool IsCheckedCast = false) {
+ Optional<std::string> CastFromName = (CE->getNumArgs() > 0)
+ ? getCastName(CE->getArg(0))
+ : Optional<std::string>();
std::string CastToName = getCastName(CE);
- const NoteTag *CastTag = C.getNoteTag(
- [CastFromName, CastToName](BugReport &) -> std::string {
+ return C.getNoteTag(
+ [CastFromName, CastToName, IsNullReturn,
+ IsCheckedCast](BugReport &) -> std::string {
SmallString<128> Msg;
llvm::raw_svector_ostream Out(Msg);
- Out << "Assuming dynamic cast from '" << CastFromName << "' to '"
- << CastToName << "' succeeds";
+ Out << (!IsCheckedCast ? "Assuming dynamic cast " : "Checked cast ");
+ if (CastFromName)
+ Out << "from '" << *CastFromName << "' ";
+
+ Out << "to '" << CastToName << "' "
+ << (!IsNullReturn ? "succeeds" : "fails");
+
return Out.str();
},
/*IsPrunable=*/true);
+}
- C.addTransition(State, CastTag);
+static ProgramStateRef getState(bool IsNullReturn,
+ DefinedOrUnknownSVal ReturnDV,
+ const CallExpr *CE, ProgramStateRef State,
+ CheckerContext &C) {
+ return State->BindExpr(
+ CE, C.getLocationContext(),
+ IsNullReturn ? C.getSValBuilder().makeNull() : ReturnDV, false);
+}
+
+//===----------------------------------------------------------------------===//
+// Evaluating cast, dyn_cast, cast_or_null, dyn_cast_or_null.
+//===----------------------------------------------------------------------===//
+
+static void evalNonNullParamNonNullReturn(const CallExpr *CE,
+ DefinedOrUnknownSVal DV,
+ CheckerContext &C,
+ bool IsCheckedCast = false) {
+ bool IsNullReturn = false;
+ if (ProgramStateRef State = C.getState()->assume(DV, true))
+ C.addTransition(getState(IsNullReturn, DV, CE, State, C),
+ getCastTag(IsNullReturn, CE, C, IsCheckedCast));
}
static void evalNonNullParamNullReturn(const CallExpr *CE,
- DefinedOrUnknownSVal ParamDV,
+ DefinedOrUnknownSVal DV,
CheckerContext &C) {
- ProgramStateRef State = C.getState()->assume(ParamDV, true);
- if (!State)
- return;
-
- State = State->BindExpr(CE, C.getLocationContext(),
- C.getSValBuilder().makeNull(), false);
-
- std::string CastFromName = getCastName(CE->getArg(0));
- std::string CastToName = getCastName(CE);
-
- const NoteTag *CastTag = C.getNoteTag(
- [CastFromName, CastToName](BugReport &) -> std::string {
- SmallString<128> Msg;
- llvm::raw_svector_ostream Out(Msg);
-
- Out << "Assuming dynamic cast from '" << CastFromName << "' to '"
- << CastToName << "' fails";
- return Out.str();
- },
- /*IsPrunable=*/true);
-
- C.addTransition(State, CastTag);
+ bool IsNullReturn = true;
+ if (ProgramStateRef State = C.getState()->assume(DV, true))
+ C.addTransition(getState(IsNullReturn, DV, CE, State, C),
+ getCastTag(IsNullReturn, CE, C));
}
-static void evalNullParamNullReturn(const CallExpr *CE,
- DefinedOrUnknownSVal ParamDV,
+static void evalNullParamNullReturn(const CallExpr *CE, DefinedOrUnknownSVal DV,
CheckerContext &C) {
- ProgramStateRef State = C.getState()->assume(ParamDV, false);
- if (!State)
- return;
-
- State = State->BindExpr(CE, C.getLocationContext(),
- C.getSValBuilder().makeNull(), false);
-
- const NoteTag *CastTag =
- C.getNoteTag("Assuming null pointer is passed into cast",
- /*IsPrunable=*/true);
-
- C.addTransition(State, CastTag);
+ if (ProgramStateRef State = C.getState()->assume(DV, false))
+ C.addTransition(getState(/*IsNullReturn=*/true, DV, CE, State, C),
+ C.getNoteTag("Assuming null pointer is passed into cast",
+ /*IsPrunable=*/true));
}
-void CastValueChecker::evalCast(const CallExpr *CE,
- DefinedOrUnknownSVal ParamDV,
+void CastValueChecker::evalCast(const CallExpr *CE, DefinedOrUnknownSVal DV,
CheckerContext &C) const {
- evalNonNullParamNonNullReturn(CE, ParamDV, C);
+ evalNonNullParamNonNullReturn(CE, DV, C, /*IsCheckedCast=*/true);
}
-void CastValueChecker::evalDynCast(const CallExpr *CE,
- DefinedOrUnknownSVal ParamDV,
+void CastValueChecker::evalDynCast(const CallExpr *CE, DefinedOrUnknownSVal DV,
CheckerContext &C) const {
- evalNonNullParamNonNullReturn(CE, ParamDV, C);
- evalNonNullParamNullReturn(CE, ParamDV, C);
+ evalNonNullParamNonNullReturn(CE, DV, C);
+ evalNonNullParamNullReturn(CE, DV, C);
}
void CastValueChecker::evalCastOrNull(const CallExpr *CE,
- DefinedOrUnknownSVal ParamDV,
+ DefinedOrUnknownSVal DV,
CheckerContext &C) const {
- evalNonNullParamNonNullReturn(CE, ParamDV, C);
- evalNullParamNullReturn(CE, ParamDV, C);
+ evalNonNullParamNonNullReturn(CE, DV, C);
+ evalNullParamNullReturn(CE, DV, C);
}
void CastValueChecker::evalDynCastOrNull(const CallExpr *CE,
- DefinedOrUnknownSVal ParamDV,
+ DefinedOrUnknownSVal DV,
CheckerContext &C) const {
- evalNonNullParamNonNullReturn(CE, ParamDV, C);
- evalNonNullParamNullReturn(CE, ParamDV, C);
- evalNullParamNullReturn(CE, ParamDV, C);
+ evalNonNullParamNonNullReturn(CE, DV, C);
+ evalNonNullParamNullReturn(CE, DV, C);
+ evalNullParamNullReturn(CE, DV, C);
+}
+
+//===----------------------------------------------------------------------===//
+// Evaluating castAs, getAs.
+//===----------------------------------------------------------------------===//
+
+static void evalZeroParamNonNullReturn(const CallExpr *CE,
+ DefinedOrUnknownSVal DV,
+ CheckerContext &C,
+ bool IsCheckedCast = false) {
+ bool IsNullReturn = false;
+ if (ProgramStateRef State = C.getState()->assume(DV, true))
+ C.addTransition(getState(IsNullReturn, DV, CE, C.getState(), C),
+ getCastTag(IsNullReturn, CE, C, IsCheckedCast));
+}
+
+static void evalZeroParamNullReturn(const CallExpr *CE, DefinedOrUnknownSVal DV,
+ CheckerContext &C) {
+ bool IsNullReturn = true;
+ if (ProgramStateRef State = C.getState()->assume(DV, true))
+ C.addTransition(getState(IsNullReturn, DV, CE, C.getState(), C),
+ getCastTag(IsNullReturn, CE, C));
+}
+
+void CastValueChecker::evalCastAs(const CallExpr *CE, DefinedOrUnknownSVal DV,
+ CheckerContext &C) const {
+ evalZeroParamNonNullReturn(CE, DV, C, /*IsCheckedCast=*/true);
+}
+
+void CastValueChecker::evalGetAs(const CallExpr *CE, DefinedOrUnknownSVal DV,
+ CheckerContext &C) const {
+ evalZeroParamNonNullReturn(CE, DV, C);
+ evalZeroParamNullReturn(CE, DV, C);
}
bool CastValueChecker::evalCall(const CallEvent &Call,
CheckerContext &C) const {
- const CastCheck *Check = CDM.lookup(Call);
- if (!Check)
+ const auto *Lookup = CDM.lookup(Call);
+ if (!Lookup)
return false;
+ // If we cannot obtain the call's class we cannot be sure how to model it.
+ QualType ResultTy = Call.getResultType();
+ if (!ResultTy->getPointeeCXXRecordDecl())
+ return false;
+
+ const CastCheck &Check = Lookup->first;
+ CastKind Kind = Lookup->second;
+
const auto *CE = cast<CallExpr>(Call.getOriginExpr());
- if (!CE)
+ Optional<DefinedOrUnknownSVal> DV;
+
+ switch (Kind) {
+ case CastKind::Function: {
+ // If we cannot obtain the arg's class we cannot be sure how to model it.
+ QualType ArgTy = Call.parameters()[0]->getType();
+ if (!ArgTy->getAsCXXRecordDecl() && !ArgTy->getPointeeCXXRecordDecl())
+ return false;
+
+ DV = Call.getArgSVal(0).getAs<DefinedOrUnknownSVal>();
+ break;
+ }
+ case CastKind::Method:
+ // If we cannot obtain the 'InstanceCall' we cannot be sure how to model it.
+ const auto *InstanceCall = dyn_cast<CXXInstanceCall>(&Call);
+ if (!InstanceCall)
+ return false;
+
+ DV = InstanceCall->getCXXThisVal().getAs<DefinedOrUnknownSVal>();
+ break;
+ }
+
+ if (!DV)
return false;
- // If we cannot obtain both of the classes we cannot be sure how to model it.
- if (!CE->getType()->getPointeeCXXRecordDecl() ||
- !CE->getArg(0)->getType()->getPointeeCXXRecordDecl())
- return false;
-
- SVal ParamV = Call.getArgSVal(0);
- auto ParamDV = ParamV.getAs<DefinedOrUnknownSVal>();
- if (!ParamDV)
- return false;
-
- (*Check)(this, CE, *ParamDV, C);
+ Check(this, CE, *DV, C);
return true;
}