Add support for "type safety" attributes that allow checking that 'void *'
function arguments and arguments for variadic functions are of a particular
type which is determined by some other argument to the same function call.
Usecases include:
* MPI library implementations, where these attributes enable checking that
buffer type matches the passed MPI_Datatype;
* for HDF5 library there is a similar usecase as MPI;
* checking types of variadic functions' arguments for functions like
fcntl() and ioctl().
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@162067 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index 3702861..2559f00 100644
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -513,6 +513,13 @@
I = FDecl->specific_attr_begin<NonNullAttr>(),
E = FDecl->specific_attr_end<NonNullAttr>(); I != E; ++I)
CheckNonNullArguments(*I, Args, Loc);
+
+ // Type safety checking.
+ for (specific_attr_iterator<ArgumentWithTypeTagAttr>
+ i = FDecl->specific_attr_begin<ArgumentWithTypeTagAttr>(),
+ e = FDecl->specific_attr_end<ArgumentWithTypeTagAttr>(); i != e; ++i) {
+ CheckArgumentWithTypeTag(*i, Args);
+ }
}
/// CheckConstructorCall - Check a constructor call for correctness and safety
@@ -5468,3 +5475,410 @@
Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line);
}
}
+
+//===--- Layout compatibility ----------------------------------------------//
+
+namespace {
+
+bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2);
+
+/// \brief Check if two enumeration types are layout-compatible.
+bool isLayoutCompatible(ASTContext &C, EnumDecl *ED1, EnumDecl *ED2) {
+ // C++11 [dcl.enum] p8:
+ // Two enumeration types are layout-compatible if they have the same
+ // underlying type.
+ return ED1->isComplete() && ED2->isComplete() &&
+ C.hasSameType(ED1->getIntegerType(), ED2->getIntegerType());
+}
+
+/// \brief Check if two fields are layout-compatible.
+bool isLayoutCompatible(ASTContext &C, FieldDecl *Field1, FieldDecl *Field2) {
+ if (!isLayoutCompatible(C, Field1->getType(), Field2->getType()))
+ return false;
+
+ if (Field1->isBitField() != Field2->isBitField())
+ return false;
+
+ if (Field1->isBitField()) {
+ // Make sure that the bit-fields are the same length.
+ unsigned Bits1 = Field1->getBitWidthValue(C);
+ unsigned Bits2 = Field2->getBitWidthValue(C);
+
+ if (Bits1 != Bits2)
+ return false;
+ }
+
+ return true;
+}
+
+/// \brief Check if two standard-layout structs are layout-compatible.
+/// (C++11 [class.mem] p17)
+bool isLayoutCompatibleStruct(ASTContext &C,
+ RecordDecl *RD1,
+ RecordDecl *RD2) {
+ // If both records are C++ classes, check that base classes match.
+ if (const CXXRecordDecl *D1CXX = dyn_cast<CXXRecordDecl>(RD1)) {
+ // If one of records is a CXXRecordDecl we are in C++ mode,
+ // thus the other one is a CXXRecordDecl, too.
+ const CXXRecordDecl *D2CXX = cast<CXXRecordDecl>(RD2);
+ // Check number of base classes.
+ if (D1CXX->getNumBases() != D2CXX->getNumBases())
+ return false;
+
+ // Check the base classes.
+ for (CXXRecordDecl::base_class_const_iterator
+ Base1 = D1CXX->bases_begin(),
+ BaseEnd1 = D1CXX->bases_end(),
+ Base2 = D2CXX->bases_begin();
+ Base1 != BaseEnd1;
+ ++Base1, ++Base2) {
+ if (!isLayoutCompatible(C, Base1->getType(), Base2->getType()))
+ return false;
+ }
+ } else if (const CXXRecordDecl *D2CXX = dyn_cast<CXXRecordDecl>(RD2)) {
+ // If only RD2 is a C++ class, it should have zero base classes.
+ if (D2CXX->getNumBases() > 0)
+ return false;
+ }
+
+ // Check the fields.
+ RecordDecl::field_iterator Field2 = RD2->field_begin(),
+ Field2End = RD2->field_end(),
+ Field1 = RD1->field_begin(),
+ Field1End = RD1->field_end();
+ for ( ; Field1 != Field1End && Field2 != Field2End; ++Field1, ++Field2) {
+ if (!isLayoutCompatible(C, *Field1, *Field2))
+ return false;
+ }
+ if (Field1 != Field1End || Field2 != Field2End)
+ return false;
+
+ return true;
+}
+
+/// \brief Check if two standard-layout unions are layout-compatible.
+/// (C++11 [class.mem] p18)
+bool isLayoutCompatibleUnion(ASTContext &C,
+ RecordDecl *RD1,
+ RecordDecl *RD2) {
+ llvm::SmallPtrSet<FieldDecl *, 8> UnmatchedFields;
+ for (RecordDecl::field_iterator Field2 = RD2->field_begin(),
+ Field2End = RD2->field_end();
+ Field2 != Field2End; ++Field2) {
+ UnmatchedFields.insert(*Field2);
+ }
+
+ for (RecordDecl::field_iterator Field1 = RD1->field_begin(),
+ Field1End = RD1->field_end();
+ Field1 != Field1End; ++Field1) {
+ llvm::SmallPtrSet<FieldDecl *, 8>::iterator
+ I = UnmatchedFields.begin(),
+ E = UnmatchedFields.end();
+
+ for ( ; I != E; ++I) {
+ if (isLayoutCompatible(C, *Field1, *I)) {
+ bool Result = UnmatchedFields.erase(*I);
+ (void) Result;
+ assert(Result);
+ break;
+ }
+ }
+ if (I == E)
+ return false;
+ }
+
+ return UnmatchedFields.empty();
+}
+
+bool isLayoutCompatible(ASTContext &C, RecordDecl *RD1, RecordDecl *RD2) {
+ if (RD1->isUnion() != RD2->isUnion())
+ return false;
+
+ if (RD1->isUnion())
+ return isLayoutCompatibleUnion(C, RD1, RD2);
+ else
+ return isLayoutCompatibleStruct(C, RD1, RD2);
+}
+
+/// \brief Check if two types are layout-compatible in C++11 sense.
+bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2) {
+ if (T1.isNull() || T2.isNull())
+ return false;
+
+ // C++11 [basic.types] p11:
+ // If two types T1 and T2 are the same type, then T1 and T2 are
+ // layout-compatible types.
+ if (C.hasSameType(T1, T2))
+ return true;
+
+ T1 = T1.getCanonicalType().getUnqualifiedType();
+ T2 = T2.getCanonicalType().getUnqualifiedType();
+
+ const Type::TypeClass TC1 = T1->getTypeClass();
+ const Type::TypeClass TC2 = T2->getTypeClass();
+
+ if (TC1 != TC2)
+ return false;
+
+ if (TC1 == Type::Enum) {
+ return isLayoutCompatible(C,
+ cast<EnumType>(T1)->getDecl(),
+ cast<EnumType>(T2)->getDecl());
+ } else if (TC1 == Type::Record) {
+ if (!T1->isStandardLayoutType() || !T2->isStandardLayoutType())
+ return false;
+
+ return isLayoutCompatible(C,
+ cast<RecordType>(T1)->getDecl(),
+ cast<RecordType>(T2)->getDecl());
+ }
+
+ return false;
+}
+}
+
+//===--- CHECK: pointer_with_type_tag attribute: datatypes should match ----//
+
+namespace {
+/// \brief Given a type tag expression find the type tag itself.
+///
+/// \param TypeExpr Type tag expression, as it appears in user's code.
+///
+/// \param VD Declaration of an identifier that appears in a type tag.
+///
+/// \param MagicValue Type tag magic value.
+bool FindTypeTagExpr(const Expr *TypeExpr, const ASTContext &Ctx,
+ const ValueDecl **VD, uint64_t *MagicValue) {
+ while(true) {
+ if (!TypeExpr)
+ return false;
+
+ TypeExpr = TypeExpr->IgnoreParenImpCasts()->IgnoreParenCasts();
+
+ switch (TypeExpr->getStmtClass()) {
+ case Stmt::UnaryOperatorClass: {
+ const UnaryOperator *UO = cast<UnaryOperator>(TypeExpr);
+ if (UO->getOpcode() == UO_AddrOf || UO->getOpcode() == UO_Deref) {
+ TypeExpr = UO->getSubExpr();
+ continue;
+ }
+ return false;
+ }
+
+ case Stmt::DeclRefExprClass: {
+ const DeclRefExpr *DRE = cast<DeclRefExpr>(TypeExpr);
+ *VD = DRE->getDecl();
+ return true;
+ }
+
+ case Stmt::IntegerLiteralClass: {
+ const IntegerLiteral *IL = cast<IntegerLiteral>(TypeExpr);
+ llvm::APInt MagicValueAPInt = IL->getValue();
+ if (MagicValueAPInt.getActiveBits() <= 64) {
+ *MagicValue = MagicValueAPInt.getZExtValue();
+ return true;
+ } else
+ return false;
+ }
+
+ case Stmt::BinaryConditionalOperatorClass:
+ case Stmt::ConditionalOperatorClass: {
+ const AbstractConditionalOperator *ACO =
+ cast<AbstractConditionalOperator>(TypeExpr);
+ bool Result;
+ if (ACO->getCond()->EvaluateAsBooleanCondition(Result, Ctx)) {
+ if (Result)
+ TypeExpr = ACO->getTrueExpr();
+ else
+ TypeExpr = ACO->getFalseExpr();
+ continue;
+ }
+ return false;
+ }
+
+ case Stmt::BinaryOperatorClass: {
+ const BinaryOperator *BO = cast<BinaryOperator>(TypeExpr);
+ if (BO->getOpcode() == BO_Comma) {
+ TypeExpr = BO->getRHS();
+ continue;
+ }
+ return false;
+ }
+
+ default:
+ return false;
+ }
+ }
+}
+
+/// \brief Retrieve the C type corresponding to type tag TypeExpr.
+///
+/// \param TypeExpr Expression that specifies a type tag.
+///
+/// \param MagicValues Registered magic values.
+///
+/// \param FoundWrongKind Set to true if a type tag was found, but of a wrong
+/// kind.
+///
+/// \param TypeInfo Information about the corresponding C type.
+///
+/// \returns true if the corresponding C type was found.
+bool GetMatchingCType(
+ const IdentifierInfo *ArgumentKind,
+ const Expr *TypeExpr, const ASTContext &Ctx,
+ const llvm::DenseMap<Sema::TypeTagMagicValue,
+ Sema::TypeTagData> *MagicValues,
+ bool &FoundWrongKind,
+ Sema::TypeTagData &TypeInfo) {
+ FoundWrongKind = false;
+
+ // Variable declaration that has type_tag_for_datatype attribute.
+ const ValueDecl *VD = NULL;
+
+ uint64_t MagicValue;
+
+ if (!FindTypeTagExpr(TypeExpr, Ctx, &VD, &MagicValue))
+ return false;
+
+ if (VD) {
+ for (specific_attr_iterator<TypeTagForDatatypeAttr>
+ I = VD->specific_attr_begin<TypeTagForDatatypeAttr>(),
+ E = VD->specific_attr_end<TypeTagForDatatypeAttr>();
+ I != E; ++I) {
+ if (I->getArgumentKind() != ArgumentKind) {
+ FoundWrongKind = true;
+ return false;
+ }
+ TypeInfo.Type = I->getMatchingCType();
+ TypeInfo.LayoutCompatible = I->getLayoutCompatible();
+ TypeInfo.MustBeNull = I->getMustBeNull();
+ return true;
+ }
+ return false;
+ }
+
+ if (!MagicValues)
+ return false;
+
+ llvm::DenseMap<Sema::TypeTagMagicValue,
+ Sema::TypeTagData>::const_iterator I =
+ MagicValues->find(std::make_pair(ArgumentKind, MagicValue));
+ if (I == MagicValues->end())
+ return false;
+
+ TypeInfo = I->second;
+ return true;
+}
+} // unnamed namespace
+
+void Sema::RegisterTypeTagForDatatype(const IdentifierInfo *ArgumentKind,
+ uint64_t MagicValue, QualType Type,
+ bool LayoutCompatible,
+ bool MustBeNull) {
+ if (!TypeTagForDatatypeMagicValues)
+ TypeTagForDatatypeMagicValues.reset(
+ new llvm::DenseMap<TypeTagMagicValue, TypeTagData>);
+
+ TypeTagMagicValue Magic(ArgumentKind, MagicValue);
+ (*TypeTagForDatatypeMagicValues)[Magic] =
+ TypeTagData(Type, LayoutCompatible, MustBeNull);
+}
+
+namespace {
+bool IsSameCharType(QualType T1, QualType T2) {
+ const BuiltinType *BT1 = T1->getAs<BuiltinType>();
+ if (!BT1)
+ return false;
+
+ const BuiltinType *BT2 = T2->getAs<BuiltinType>();
+ if (!BT2)
+ return false;
+
+ BuiltinType::Kind T1Kind = BT1->getKind();
+ BuiltinType::Kind T2Kind = BT2->getKind();
+
+ return (T1Kind == BuiltinType::SChar && T2Kind == BuiltinType::Char_S) ||
+ (T1Kind == BuiltinType::UChar && T2Kind == BuiltinType::Char_U) ||
+ (T1Kind == BuiltinType::Char_U && T2Kind == BuiltinType::UChar) ||
+ (T1Kind == BuiltinType::Char_S && T2Kind == BuiltinType::SChar);
+}
+} // unnamed namespace
+
+void Sema::CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr,
+ const Expr * const *ExprArgs) {
+ const IdentifierInfo *ArgumentKind = Attr->getArgumentKind();
+ bool IsPointerAttr = Attr->getIsPointer();
+
+ const Expr *TypeTagExpr = ExprArgs[Attr->getTypeTagIdx()];
+ bool FoundWrongKind;
+ TypeTagData TypeInfo;
+ if (!GetMatchingCType(ArgumentKind, TypeTagExpr, Context,
+ TypeTagForDatatypeMagicValues.get(),
+ FoundWrongKind, TypeInfo)) {
+ if (FoundWrongKind)
+ Diag(TypeTagExpr->getExprLoc(),
+ diag::warn_type_tag_for_datatype_wrong_kind)
+ << TypeTagExpr->getSourceRange();
+ return;
+ }
+
+ const Expr *ArgumentExpr = ExprArgs[Attr->getArgumentIdx()];
+ if (IsPointerAttr) {
+ // Skip implicit cast of pointer to `void *' (as a function argument).
+ if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgumentExpr))
+ if (ICE->getType()->isVoidPointerType())
+ ArgumentExpr = ICE->getSubExpr();
+ }
+ QualType ArgumentType = ArgumentExpr->getType();
+
+ // Passing a `void*' pointer shouldn't trigger a warning.
+ if (IsPointerAttr && ArgumentType->isVoidPointerType())
+ return;
+
+ if (TypeInfo.MustBeNull) {
+ // Type tag with matching void type requires a null pointer.
+ if (!ArgumentExpr->isNullPointerConstant(Context,
+ Expr::NPC_ValueDependentIsNotNull)) {
+ Diag(ArgumentExpr->getExprLoc(),
+ diag::warn_type_safety_null_pointer_required)
+ << ArgumentKind->getName()
+ << ArgumentExpr->getSourceRange()
+ << TypeTagExpr->getSourceRange();
+ }
+ return;
+ }
+
+ QualType RequiredType = TypeInfo.Type;
+ if (IsPointerAttr)
+ RequiredType = Context.getPointerType(RequiredType);
+
+ bool mismatch = false;
+ if (!TypeInfo.LayoutCompatible) {
+ mismatch = !Context.hasSameType(ArgumentType, RequiredType);
+
+ // C++11 [basic.fundamental] p1:
+ // Plain char, signed char, and unsigned char are three distinct types.
+ //
+ // But we treat plain `char' as equivalent to `signed char' or `unsigned
+ // char' depending on the current char signedness mode.
+ if (mismatch)
+ if ((IsPointerAttr && IsSameCharType(ArgumentType->getPointeeType(),
+ RequiredType->getPointeeType())) ||
+ (!IsPointerAttr && IsSameCharType(ArgumentType, RequiredType)))
+ mismatch = false;
+ } else
+ if (IsPointerAttr)
+ mismatch = !isLayoutCompatible(Context,
+ ArgumentType->getPointeeType(),
+ RequiredType->getPointeeType());
+ else
+ mismatch = !isLayoutCompatible(Context, ArgumentType, RequiredType);
+
+ if (mismatch)
+ Diag(ArgumentExpr->getExprLoc(), diag::warn_type_safety_type_mismatch)
+ << ArgumentType << ArgumentKind->getName()
+ << TypeInfo.LayoutCompatible << RequiredType
+ << ArgumentExpr->getSourceRange()
+ << TypeTagExpr->getSourceRange();
+}
+