forked from OSchip/llvm-project
[analyzer] Fix null pointer deref in CastValueChecker
A crash was seen in CastValueChecker due to a null pointer dereference. The fix uses QualType::getAsString to avoid the null dereference when a CXXRecordDecl cannot be obtained. A small reproducer is added, and cast value notes LITs are updated for the new debug messages. Reviewed By: steakhal Differential Revision: https://reviews.llvm.org/D127105
This commit is contained in:
Vince Bridgers
einvbri
parent
82040d414b
commit
c7fa4e8a8b
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@ -108,7 +108,7 @@ static const NoteTag *getNoteTag(CheckerContext &C,
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bool CastSucceeds, bool IsKnownCast) {
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std::string CastToName =
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CastInfo ? CastInfo->to()->getAsCXXRecordDecl()->getNameAsString()
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: CastToTy->getPointeeCXXRecordDecl()->getNameAsString();
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: CastToTy.getAsString();
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Object = Object->IgnoreParenImpCasts();
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return C.getNoteTag(
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@ -163,9 +163,9 @@ static const NoteTag *getNoteTag(CheckerContext &C,
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bool First = true;
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for (QualType CastToTy: CastToTyVec) {
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std::string CastToName =
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CastToTy->getAsCXXRecordDecl() ?
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CastToTy->getAsCXXRecordDecl()->getNameAsString() :
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CastToTy->getPointeeCXXRecordDecl()->getNameAsString();
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CastToTy->getAsCXXRecordDecl()
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? CastToTy->getAsCXXRecordDecl()->getNameAsString()
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: CastToTy.getAsString();
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Out << ' ' << ((CastToTyVec.size() == 1) ? "not" :
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(First ? "neither" : "nor")) << " a '" << CastToName
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<< '\'';
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@ -73,7 +73,7 @@ void clang_analyzer_printState();
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#if defined(X86)
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void evalReferences(const Shape &S) {
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const auto &C = dyn_cast<Circle>(S);
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// expected-note@-1 {{Assuming 'S' is not a 'Circle'}}
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// expected-note@-1 {{Assuming 'S' is not a 'const class clang::Circle &'}}
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// expected-note@-2 {{Dereference of null pointer}}
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// expected-warning@-3 {{Dereference of null pointer}}
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clang_analyzer_printState();
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@ -93,7 +93,7 @@ void evalReferences_addrspace(const Shape &S) {
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#if defined(NOT_SUPPRESSED)
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void evalReferences_addrspace(const Shape &S) {
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const auto &C = dyn_cast<DEVICE Circle>(S);
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// expected-note@-1 {{Assuming 'S' is not a 'Circle'}}
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// expected-note@-1 {{Assuming 'S' is not a 'const __attribute__((address_space(3))) class clang::Circle &'}}
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// expected-note@-2 {{Dereference of null pointer}}
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// expected-warning@-3 {{Dereference of null pointer}}
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clang_analyzer_printState();
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@ -105,7 +105,7 @@ void evalReferences_addrspace(const Shape &S) {
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#elif defined(MIPS)
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void evalReferences(const Shape &S) {
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const auto &C = dyn_cast<Circle>(S);
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// expected-note@-1 {{Assuming 'S' is not a 'Circle'}}
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// expected-note@-1 {{Assuming 'S' is not a 'const class clang::Circle &'}}
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// expected-note@-2 {{Dereference of null pointer}}
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// expected-warning@-3 {{Dereference of null pointer}}
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}
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@ -122,25 +122,25 @@ void evalNonNullParamNonNullReturnReference(const Shape &S) {
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// expected-note@-1 {{'C' initialized here}}
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if (!dyn_cast_or_null<Circle>(C)) {
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// expected-note@-1 {{'C' is a 'Circle'}}
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// expected-note@-1 {{Assuming 'C' is a 'const class clang::Circle *'}}
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// expected-note@-2 {{Taking false branch}}
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return;
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}
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if (dyn_cast_or_null<Triangle>(C)) {
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// expected-note@-1 {{Assuming 'C' is not a 'Triangle'}}
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// expected-note@-1 {{Assuming 'C' is not a 'const class clang::Triangle *'}}
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// expected-note@-2 {{Taking false branch}}
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return;
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}
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if (dyn_cast_or_null<Rectangle>(C)) {
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// expected-note@-1 {{Assuming 'C' is not a 'Rectangle'}}
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// expected-note@-1 {{Assuming 'C' is not a 'const class clang::Rectangle *'}}
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// expected-note@-2 {{Taking false branch}}
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return;
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}
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if (dyn_cast_or_null<Hexagon>(C)) {
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// expected-note@-1 {{Assuming 'C' is not a 'Hexagon'}}
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// expected-note@-1 {{Assuming 'C' is not a 'const class clang::Hexagon *'}}
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// expected-note@-2 {{Taking false branch}}
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return;
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}
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@ -176,29 +176,29 @@ void evalNonNullParamNonNullReturnReference(const Shape &S) {
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void evalNonNullParamNonNullReturn(const Shape *S) {
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const auto *C = cast<Circle>(S);
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// expected-note@-1 {{'S' is a 'Circle'}}
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// expected-note@-1 {{'S' is a 'const class clang::Circle *'}}
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// expected-note@-2 {{'C' initialized here}}
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if (!dyn_cast_or_null<Circle>(C)) {
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// expected-note@-1 {{'C' is a 'Circle'}}
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// expected-note@-1 {{Assuming 'C' is a 'const class clang::Circle *'}}
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// expected-note@-2 {{Taking false branch}}
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return;
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}
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if (dyn_cast_or_null<Triangle>(C)) {
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// expected-note@-1 {{Assuming 'C' is not a 'Triangle'}}
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// expected-note@-1 {{Assuming 'C' is not a 'const class clang::Triangle *'}}
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// expected-note@-2 {{Taking false branch}}
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return;
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}
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if (dyn_cast_or_null<Rectangle>(C)) {
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// expected-note@-1 {{Assuming 'C' is not a 'Rectangle'}}
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// expected-note@-1 {{Assuming 'C' is not a 'const class clang::Rectangle *'}}
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// expected-note@-2 {{Taking false branch}}
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return;
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}
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if (dyn_cast_or_null<Hexagon>(C)) {
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// expected-note@-1 {{Assuming 'C' is not a 'Hexagon'}}
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// expected-note@-1 {{Assuming 'C' is not a 'const class clang::Hexagon *'}}
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// expected-note@-2 {{Taking false branch}}
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return;
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}
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@ -234,10 +234,10 @@ void evalNonNullParamNonNullReturn(const Shape *S) {
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void evalNonNullParamNullReturn(const Shape *S) {
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const auto *C = dyn_cast_or_null<Circle>(S);
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// expected-note@-1 {{Assuming 'S' is not a 'Circle'}}
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// expected-note@-1 {{Assuming 'S' is not a 'const class clang::Circle *'}}
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if (const auto *T = dyn_cast_or_null<Triangle>(S)) {
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// expected-note@-1 {{Assuming 'S' is a 'Triangle'}}
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// expected-note@-1 {{Assuming 'S' is a 'const class clang::Triangle *'}}
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// expected-note@-2 {{'T' initialized here}}
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// expected-note@-3 {{'T' is non-null}}
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// expected-note@-4 {{Taking true branch}}
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@ -261,7 +261,7 @@ void evalNullParamNullReturn(const Shape *S) {
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void evalZeroParamNonNullReturnPointer(const Shape *S) {
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const auto *C = S->castAs<Circle>();
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// expected-note@-1 {{'S' is a 'Circle'}}
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// expected-note@-1 {{'S' is a 'const class clang::Circle *'}}
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// expected-note@-2 {{'C' initialized here}}
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(void)(1 / !C);
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@ -282,12 +282,12 @@ void evalZeroParamNonNullReturn(const Shape &S) {
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void evalZeroParamNullReturn(const Shape *S) {
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const auto &C = S->getAs<Circle>();
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// expected-note@-1 {{Assuming 'S' is not a 'Circle'}}
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// expected-note@-1 {{Assuming 'S' is not a 'const class clang::Circle *'}}
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// expected-note@-2 {{Storing null pointer value}}
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// expected-note@-3 {{'C' initialized here}}
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if (!dyn_cast_or_null<Triangle>(S)) {
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// expected-note@-1 {{Assuming 'S' is a 'Triangle'}}
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// expected-note@-1 {{Assuming 'S' is a 'const class clang::Triangle *'}}
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// expected-note@-2 {{Taking false branch}}
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return;
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}
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@ -302,3 +302,32 @@ void evalZeroParamNullReturn(const Shape *S) {
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// expected-note@-1 {{Division by zero}}
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// expected-warning@-2 {{Division by zero}}
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}
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// don't crash
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// CastValueChecker was using QualType()->getPointeeCXXRecordDecl(), in
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// getNoteTag which evaluated to nullptr, then crashed when attempting to
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// deref an invocation to getNameAsString(). The fix is to use
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// QualType().getAsString().
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//
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// Example:
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// std::string CastToName =
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// CastInfo ? CastInfo->to()->getAsCXXRecordDecl()->getNameAsString()
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// : CastToTy->getPointeeCXXRecordDecl()->getNameAsString();
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// Changed to:
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// std::string CastToName =
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// CastInfo ? CastInfo->to()->getAsCXXRecordDecl()->getNameAsString()
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// : CastToTy.getAsString();
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namespace llvm {
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template <typename, typename a> void isa(a &);
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template <typename> class PointerUnion {
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public:
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template <typename T> T *getAs() {
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(void)isa<int>(*this);
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return nullptr;
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}
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};
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class LLVMContext {
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PointerUnion<LLVMContext> c;
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void d() { c.getAs<int>(); }
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};
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} // namespace llvm
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@ -18,12 +18,12 @@ using namespace clang;
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void evalNonNullParamNonNullReturn(const Shape *S) {
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const auto *C = dyn_cast_or_null<Circle>(S);
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// expected-note@-1 {{Assuming 'S' is a 'Circle'}}
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// expected-note@-1 {{Assuming 'S' is a 'const class clang::Circle *'}}
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// expected-note@-2 {{'C' initialized here}}
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// FIXME: We assumed that 'S' is a 'Circle' therefore it is not a 'Square'.
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if (dyn_cast_or_null<Square>(S)) {
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// expected-note@-1 {{Assuming 'S' is not a 'Square'}}
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// expected-note@-1 {{Assuming 'S' is not a 'const class clang::Square *'}}
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// expected-note@-2 {{Taking false branch}}
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return;
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}
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