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Diffstat (limited to 'clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp')
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diff --git a/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp new file mode 100644 index 000000000000..2cdee8da375e --- /dev/null +++ b/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp @@ -0,0 +1,1065 @@ +//=== StdLibraryFunctionsChecker.cpp - Model standard functions -*- C++ -*-===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// This checker improves modeling of a few simple library functions. +// It does not generate warnings. +// +// This checker provides a specification format - `FunctionSummaryTy' - and +// contains descriptions of some library functions in this format. Each +// specification contains a list of branches for splitting the program state +// upon call, and range constraints on argument and return-value symbols that +// are satisfied on each branch. This spec can be expanded to include more +// items, like external effects of the function. +// +// The main difference between this approach and the body farms technique is +// in more explicit control over how many branches are produced. For example, +// consider standard C function `ispunct(int x)', which returns a non-zero value +// iff `x' is a punctuation character, that is, when `x' is in range +// ['!', '/'] [':', '@'] U ['[', '\`'] U ['{', '~']. +// `FunctionSummaryTy' provides only two branches for this function. However, +// any attempt to describe this range with if-statements in the body farm +// would result in many more branches. Because each branch needs to be analyzed +// independently, this significantly reduces performance. Additionally, +// once we consider a branch on which `x' is in range, say, ['!', '/'], +// we assume that such branch is an important separate path through the program, +// which may lead to false positives because considering this particular path +// was not consciously intended, and therefore it might have been unreachable. +// +// This checker uses eval::Call for modeling "pure" functions, for which +// their `FunctionSummaryTy' is a precise model. This avoids unnecessary +// invalidation passes. Conflicts with other checkers are unlikely because +// if the function has no other effects, other checkers would probably never +// want to improve upon the modeling done by this checker. +// +// Non-"pure" functions, for which only partial improvement over the default +// behavior is expected, are modeled via check::PostCall, non-intrusively. +// +// The following standard C functions are currently supported: +// +// fgetc getline isdigit isupper +// fread isalnum isgraph isxdigit +// fwrite isalpha islower read +// getc isascii isprint write +// getchar isblank ispunct +// getdelim iscntrl isspace +// +//===----------------------------------------------------------------------===// + +#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.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" + +using namespace clang; +using namespace clang::ento; + +namespace { +class StdLibraryFunctionsChecker : public Checker<check::PostCall, eval::Call> { + /// Below is a series of typedefs necessary to define function specs. + /// We avoid nesting types here because each additional qualifier + /// would need to be repeated in every function spec. + struct FunctionSummaryTy; + + /// Specify how much the analyzer engine should entrust modeling this function + /// to us. If he doesn't, he performs additional invalidations. + enum InvalidationKindTy { NoEvalCall, EvalCallAsPure }; + + /// A pair of ValueRangeKindTy and IntRangeVectorTy would describe a range + /// imposed on a particular argument or return value symbol. + /// + /// Given a range, should the argument stay inside or outside this range? + /// The special `ComparesToArgument' value indicates that we should + /// impose a constraint that involves other argument or return value symbols. + enum ValueRangeKindTy { OutOfRange, WithinRange, ComparesToArgument }; + + // The universal integral type to use in value range descriptions. + // Unsigned to make sure overflows are well-defined. + typedef uint64_t RangeIntTy; + + /// Normally, describes a single range constraint, eg. {{0, 1}, {3, 4}} is + /// a non-negative integer, which less than 5 and not equal to 2. For + /// `ComparesToArgument', holds information about how exactly to compare to + /// the argument. + typedef std::vector<std::pair<RangeIntTy, RangeIntTy>> IntRangeVectorTy; + + /// A reference to an argument or return value by its number. + /// ArgNo in CallExpr and CallEvent is defined as Unsigned, but + /// obviously uint32_t should be enough for all practical purposes. + typedef uint32_t ArgNoTy; + static const ArgNoTy Ret = std::numeric_limits<ArgNoTy>::max(); + + /// Incapsulates a single range on a single symbol within a branch. + class ValueRange { + ArgNoTy ArgNo; // Argument to which we apply the range. + ValueRangeKindTy Kind; // Kind of range definition. + IntRangeVectorTy Args; // Polymorphic arguments. + + public: + ValueRange(ArgNoTy ArgNo, ValueRangeKindTy Kind, + const IntRangeVectorTy &Args) + : ArgNo(ArgNo), Kind(Kind), Args(Args) {} + + ArgNoTy getArgNo() const { return ArgNo; } + ValueRangeKindTy getKind() const { return Kind; } + + BinaryOperator::Opcode getOpcode() const { + assert(Kind == ComparesToArgument); + assert(Args.size() == 1); + BinaryOperator::Opcode Op = + static_cast<BinaryOperator::Opcode>(Args[0].first); + assert(BinaryOperator::isComparisonOp(Op) && + "Only comparison ops are supported for ComparesToArgument"); + return Op; + } + + ArgNoTy getOtherArgNo() const { + assert(Kind == ComparesToArgument); + assert(Args.size() == 1); + return static_cast<ArgNoTy>(Args[0].second); + } + + const IntRangeVectorTy &getRanges() const { + assert(Kind != ComparesToArgument); + return Args; + } + + // We avoid creating a virtual apply() method because + // it makes initializer lists harder to write. + private: + ProgramStateRef + applyAsOutOfRange(ProgramStateRef State, const CallEvent &Call, + const FunctionSummaryTy &Summary) const; + ProgramStateRef + applyAsWithinRange(ProgramStateRef State, const CallEvent &Call, + const FunctionSummaryTy &Summary) const; + ProgramStateRef + applyAsComparesToArgument(ProgramStateRef State, const CallEvent &Call, + const FunctionSummaryTy &Summary) const; + + public: + ProgramStateRef apply(ProgramStateRef State, const CallEvent &Call, + const FunctionSummaryTy &Summary) const { + switch (Kind) { + case OutOfRange: + return applyAsOutOfRange(State, Call, Summary); + case WithinRange: + return applyAsWithinRange(State, Call, Summary); + case ComparesToArgument: + return applyAsComparesToArgument(State, Call, Summary); + } + llvm_unreachable("Unknown ValueRange kind!"); + } + }; + + /// The complete list of ranges that defines a single branch. + typedef std::vector<ValueRange> ValueRangeSet; + + /// Includes information about function prototype (which is necessary to + /// ensure we're modeling the right function and casting values properly), + /// approach to invalidation, and a list of branches - essentially, a list + /// of list of ranges - essentially, a list of lists of lists of segments. + struct FunctionSummaryTy { + const std::vector<QualType> ArgTypes; + const QualType RetType; + const InvalidationKindTy InvalidationKind; + const std::vector<ValueRangeSet> Ranges; + + private: + static void assertTypeSuitableForSummary(QualType T) { + assert(!T->isVoidType() && + "We should have had no significant void types in the spec"); + assert(T.isCanonical() && + "We should only have canonical types in the spec"); + // FIXME: lift this assert (but not the ones above!) + assert(T->isIntegralOrEnumerationType() && + "We only support integral ranges in the spec"); + } + + public: + QualType getArgType(ArgNoTy ArgNo) const { + QualType T = (ArgNo == Ret) ? RetType : ArgTypes[ArgNo]; + assertTypeSuitableForSummary(T); + return T; + } + + /// Try our best to figure out if the call expression is the call of + /// *the* library function to which this specification applies. + bool matchesCall(const CallExpr *CE) const; + }; + + // The same function (as in, function identifier) may have different + // summaries assigned to it, with different argument and return value types. + // We call these "variants" of the function. This can be useful for handling + // C++ function overloads, and also it can be used when the same function + // may have different definitions on different platforms. + typedef std::vector<FunctionSummaryTy> FunctionVariantsTy; + + // The map of all functions supported by the checker. It is initialized + // lazily, and it doesn't change after initialization. + typedef llvm::StringMap<FunctionVariantsTy> FunctionSummaryMapTy; + mutable FunctionSummaryMapTy FunctionSummaryMap; + + // Auxiliary functions to support ArgNoTy within all structures + // in a unified manner. + static QualType getArgType(const FunctionSummaryTy &Summary, ArgNoTy ArgNo) { + return Summary.getArgType(ArgNo); + } + static QualType getArgType(const CallEvent &Call, ArgNoTy ArgNo) { + return ArgNo == Ret ? Call.getResultType().getCanonicalType() + : Call.getArgExpr(ArgNo)->getType().getCanonicalType(); + } + static QualType getArgType(const CallExpr *CE, ArgNoTy ArgNo) { + return ArgNo == Ret ? CE->getType().getCanonicalType() + : CE->getArg(ArgNo)->getType().getCanonicalType(); + } + static SVal getArgSVal(const CallEvent &Call, ArgNoTy ArgNo) { + return ArgNo == Ret ? Call.getReturnValue() : Call.getArgSVal(ArgNo); + } + +public: + void checkPostCall(const CallEvent &Call, CheckerContext &C) const; + bool evalCall(const CallEvent &Call, CheckerContext &C) const; + +private: + Optional<FunctionSummaryTy> findFunctionSummary(const FunctionDecl *FD, + const CallExpr *CE, + CheckerContext &C) const; + + void initFunctionSummaries(BasicValueFactory &BVF) const; +}; +} // end of anonymous namespace + +ProgramStateRef StdLibraryFunctionsChecker::ValueRange::applyAsOutOfRange( + ProgramStateRef State, const CallEvent &Call, + const FunctionSummaryTy &Summary) const { + + ProgramStateManager &Mgr = State->getStateManager(); + SValBuilder &SVB = Mgr.getSValBuilder(); + BasicValueFactory &BVF = SVB.getBasicValueFactory(); + ConstraintManager &CM = Mgr.getConstraintManager(); + QualType T = getArgType(Summary, getArgNo()); + SVal V = getArgSVal(Call, getArgNo()); + + if (auto N = V.getAs<NonLoc>()) { + const IntRangeVectorTy &R = getRanges(); + size_t E = R.size(); + for (size_t I = 0; I != E; ++I) { + const llvm::APSInt &Min = BVF.getValue(R[I].first, T); + const llvm::APSInt &Max = BVF.getValue(R[I].second, T); + assert(Min <= Max); + State = CM.assumeInclusiveRange(State, *N, Min, Max, false); + if (!State) + break; + } + } + + return State; +} + +ProgramStateRef +StdLibraryFunctionsChecker::ValueRange::applyAsWithinRange( + ProgramStateRef State, const CallEvent &Call, + const FunctionSummaryTy &Summary) const { + + ProgramStateManager &Mgr = State->getStateManager(); + SValBuilder &SVB = Mgr.getSValBuilder(); + BasicValueFactory &BVF = SVB.getBasicValueFactory(); + ConstraintManager &CM = Mgr.getConstraintManager(); + QualType T = getArgType(Summary, getArgNo()); + SVal V = getArgSVal(Call, getArgNo()); + + // "WithinRange R" is treated as "outside [T_MIN, T_MAX] \ R". + // We cut off [T_MIN, min(R) - 1] and [max(R) + 1, T_MAX] if necessary, + // and then cut away all holes in R one by one. + if (auto N = V.getAs<NonLoc>()) { + const IntRangeVectorTy &R = getRanges(); + size_t E = R.size(); + + const llvm::APSInt &MinusInf = BVF.getMinValue(T); + const llvm::APSInt &PlusInf = BVF.getMaxValue(T); + + const llvm::APSInt &Left = BVF.getValue(R[0].first - 1ULL, T); + if (Left != PlusInf) { + assert(MinusInf <= Left); + State = CM.assumeInclusiveRange(State, *N, MinusInf, Left, false); + if (!State) + return nullptr; + } + + const llvm::APSInt &Right = BVF.getValue(R[E - 1].second + 1ULL, T); + if (Right != MinusInf) { + assert(Right <= PlusInf); + State = CM.assumeInclusiveRange(State, *N, Right, PlusInf, false); + if (!State) + return nullptr; + } + + for (size_t I = 1; I != E; ++I) { + const llvm::APSInt &Min = BVF.getValue(R[I - 1].second + 1ULL, T); + const llvm::APSInt &Max = BVF.getValue(R[I].first - 1ULL, T); + assert(Min <= Max); + State = CM.assumeInclusiveRange(State, *N, Min, Max, false); + if (!State) + return nullptr; + } + } + + return State; +} + +ProgramStateRef +StdLibraryFunctionsChecker::ValueRange::applyAsComparesToArgument( + ProgramStateRef State, const CallEvent &Call, + const FunctionSummaryTy &Summary) const { + + ProgramStateManager &Mgr = State->getStateManager(); + SValBuilder &SVB = Mgr.getSValBuilder(); + QualType CondT = SVB.getConditionType(); + QualType T = getArgType(Summary, getArgNo()); + SVal V = getArgSVal(Call, getArgNo()); + + BinaryOperator::Opcode Op = getOpcode(); + ArgNoTy OtherArg = getOtherArgNo(); + SVal OtherV = getArgSVal(Call, OtherArg); + QualType OtherT = getArgType(Call, OtherArg); + // Note: we avoid integral promotion for comparison. + OtherV = SVB.evalCast(OtherV, T, OtherT); + if (auto CompV = SVB.evalBinOp(State, Op, V, OtherV, CondT) + .getAs<DefinedOrUnknownSVal>()) + State = State->assume(*CompV, true); + return State; +} + +void StdLibraryFunctionsChecker::checkPostCall(const CallEvent &Call, + CheckerContext &C) const { + const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(Call.getDecl()); + if (!FD) + return; + + const CallExpr *CE = dyn_cast_or_null<CallExpr>(Call.getOriginExpr()); + if (!CE) + return; + + Optional<FunctionSummaryTy> FoundSummary = findFunctionSummary(FD, CE, C); + if (!FoundSummary) + return; + + // Now apply ranges. + const FunctionSummaryTy &Summary = *FoundSummary; + ProgramStateRef State = C.getState(); + + for (const auto &VRS: Summary.Ranges) { + ProgramStateRef NewState = State; + for (const auto &VR: VRS) { + NewState = VR.apply(NewState, Call, Summary); + if (!NewState) + break; + } + + if (NewState && NewState != State) + C.addTransition(NewState); + } +} + +bool StdLibraryFunctionsChecker::evalCall(const CallEvent &Call, + CheckerContext &C) const { + const auto *FD = dyn_cast_or_null<FunctionDecl>(Call.getDecl()); + if (!FD) + return false; + + const auto *CE = dyn_cast_or_null<CallExpr>(Call.getOriginExpr()); + if (!CE) + return false; + + Optional<FunctionSummaryTy> FoundSummary = findFunctionSummary(FD, CE, C); + if (!FoundSummary) + return false; + + const FunctionSummaryTy &Summary = *FoundSummary; + switch (Summary.InvalidationKind) { + case EvalCallAsPure: { + ProgramStateRef State = C.getState(); + const LocationContext *LC = C.getLocationContext(); + SVal V = C.getSValBuilder().conjureSymbolVal( + CE, LC, CE->getType().getCanonicalType(), C.blockCount()); + State = State->BindExpr(CE, LC, V); + C.addTransition(State); + return true; + } + case NoEvalCall: + // Summary tells us to avoid performing eval::Call. The function is possibly + // evaluated by another checker, or evaluated conservatively. + return false; + } + llvm_unreachable("Unknown invalidation kind!"); +} + +bool StdLibraryFunctionsChecker::FunctionSummaryTy::matchesCall( + const CallExpr *CE) const { + // Check number of arguments: + if (CE->getNumArgs() != ArgTypes.size()) + return false; + + // Check return type if relevant: + if (!RetType.isNull() && RetType != CE->getType().getCanonicalType()) + return false; + + // Check argument types when relevant: + for (size_t I = 0, E = ArgTypes.size(); I != E; ++I) { + QualType FormalT = ArgTypes[I]; + // Null type marks irrelevant arguments. + if (FormalT.isNull()) + continue; + + assertTypeSuitableForSummary(FormalT); + + QualType ActualT = StdLibraryFunctionsChecker::getArgType(CE, I); + assert(ActualT.isCanonical()); + if (ActualT != FormalT) + return false; + } + + return true; +} + +Optional<StdLibraryFunctionsChecker::FunctionSummaryTy> +StdLibraryFunctionsChecker::findFunctionSummary(const FunctionDecl *FD, + const CallExpr *CE, + CheckerContext &C) const { + // Note: we cannot always obtain FD from CE + // (eg. virtual call, or call by pointer). + assert(CE); + + if (!FD) + return None; + + SValBuilder &SVB = C.getSValBuilder(); + BasicValueFactory &BVF = SVB.getBasicValueFactory(); + initFunctionSummaries(BVF); + + IdentifierInfo *II = FD->getIdentifier(); + if (!II) + return None; + StringRef Name = II->getName(); + if (Name.empty() || !C.isCLibraryFunction(FD, Name)) + return None; + + auto FSMI = FunctionSummaryMap.find(Name); + if (FSMI == FunctionSummaryMap.end()) + return None; + + // Verify that function signature matches the spec in advance. + // Otherwise we might be modeling the wrong function. + // Strict checking is important because we will be conducting + // very integral-type-sensitive operations on arguments and + // return values. + const FunctionVariantsTy &SpecVariants = FSMI->second; + for (const FunctionSummaryTy &Spec : SpecVariants) + if (Spec.matchesCall(CE)) + return Spec; + + return None; +} + +void StdLibraryFunctionsChecker::initFunctionSummaries( + BasicValueFactory &BVF) const { + if (!FunctionSummaryMap.empty()) + return; + + ASTContext &ACtx = BVF.getContext(); + + // These types are useful for writing specifications quickly, + // New specifications should probably introduce more types. + // Some types are hard to obtain from the AST, eg. "ssize_t". + // In such cases it should be possible to provide multiple variants + // of function summary for common cases (eg. ssize_t could be int or long + // or long long, so three summary variants would be enough). + // Of course, function variants are also useful for C++ overloads. + QualType Irrelevant; // A placeholder, whenever we do not care about the type. + QualType IntTy = ACtx.IntTy; + QualType LongTy = ACtx.LongTy; + QualType LongLongTy = ACtx.LongLongTy; + QualType SizeTy = ACtx.getSizeType(); + + RangeIntTy IntMax = BVF.getMaxValue(IntTy).getLimitedValue(); + RangeIntTy LongMax = BVF.getMaxValue(LongTy).getLimitedValue(); + RangeIntTy LongLongMax = BVF.getMaxValue(LongLongTy).getLimitedValue(); + + // We are finally ready to define specifications for all supported functions. + // + // The signature needs to have the correct number of arguments. + // However, we insert `Irrelevant' when the type is insignificant. + // + // Argument ranges should always cover all variants. If return value + // is completely unknown, omit it from the respective range set. + // + // All types in the spec need to be canonical. + // + // Every item in the list of range sets represents a particular + // execution path the analyzer would need to explore once + // the call is modeled - a new program state is constructed + // for every range set, and each range line in the range set + // corresponds to a specific constraint within this state. + // + // Upon comparing to another argument, the other argument is casted + // to the current argument's type. This avoids proper promotion but + // seems useful. For example, read() receives size_t argument, + // and its return value, which is of type ssize_t, cannot be greater + // than this argument. If we made a promotion, and the size argument + // is equal to, say, 10, then we'd impose a range of [0, 10] on the + // return value, however the correct range is [-1, 10]. + // + // Please update the list of functions in the header after editing! + // + // The format is as follows: + // + //{ "function name", + // { spec: + // { argument types list, ... }, + // return type, purity, { range set list: + // { range list: + // { argument index, within or out of, {{from, to}, ...} }, + // { argument index, compares to argument, {{how, which}} }, + // ... + // } + // } + // } + //} + +#define SUMMARY_WITH_VARIANTS(identifier) {#identifier, { +#define END_SUMMARY_WITH_VARIANTS }}, +#define VARIANT(argument_types, return_type, invalidation_approach) \ + { argument_types, return_type, invalidation_approach, { +#define END_VARIANT } }, +#define SUMMARY(identifier, argument_types, return_type, \ + invalidation_approach) \ + { #identifier, { { argument_types, return_type, invalidation_approach, { +#define END_SUMMARY } } } }, +#define ARGUMENT_TYPES(...) { __VA_ARGS__ } +#define RETURN_TYPE(x) x +#define INVALIDATION_APPROACH(x) x +#define CASE { +#define END_CASE }, +#define ARGUMENT_CONDITION(argument_number, condition_kind) \ + { argument_number, condition_kind, { +#define END_ARGUMENT_CONDITION }}, +#define RETURN_VALUE_CONDITION(condition_kind) \ + { Ret, condition_kind, { +#define END_RETURN_VALUE_CONDITION }}, +#define ARG_NO(x) x##U +#define RANGE(x, y) { x, y }, +#define SINGLE_VALUE(x) RANGE(x, x) +#define IS_LESS_THAN(arg) { BO_LE, arg } + + FunctionSummaryMap = { + // The isascii() family of functions. + SUMMARY(isalnum, ARGUMENT_TYPES(IntTy), RETURN_TYPE(IntTy), + INVALIDATION_APPROACH(EvalCallAsPure)) + CASE // Boils down to isupper() or islower() or isdigit() + ARGUMENT_CONDITION(ARG_NO(0), WithinRange) + RANGE('0', '9') + RANGE('A', 'Z') + RANGE('a', 'z') + END_ARGUMENT_CONDITION + RETURN_VALUE_CONDITION(OutOfRange) + SINGLE_VALUE(0) + END_RETURN_VALUE_CONDITION + END_CASE + CASE // The locale-specific range. + ARGUMENT_CONDITION(ARG_NO(0), WithinRange) + RANGE(128, 255) + END_ARGUMENT_CONDITION + // No post-condition. We are completely unaware of + // locale-specific return values. + END_CASE + CASE + ARGUMENT_CONDITION(ARG_NO(0), OutOfRange) + RANGE('0', '9') + RANGE('A', 'Z') + RANGE('a', 'z') + RANGE(128, 255) + END_ARGUMENT_CONDITION + RETURN_VALUE_CONDITION(WithinRange) + SINGLE_VALUE(0) + END_RETURN_VALUE_CONDITION + END_CASE + END_SUMMARY + SUMMARY(isalpha, ARGUMENT_TYPES(IntTy), RETURN_TYPE(IntTy), + INVALIDATION_APPROACH(EvalCallAsPure)) + CASE // isupper() or islower(). Note that 'Z' is less than 'a'. + ARGUMENT_CONDITION(ARG_NO(0), WithinRange) + RANGE('A', 'Z') + RANGE('a', 'z') + END_ARGUMENT_CONDITION + RETURN_VALUE_CONDITION(OutOfRange) + SINGLE_VALUE(0) + END_RETURN_VALUE_CONDITION + END_CASE + CASE // The locale-specific range. + ARGUMENT_CONDITION(ARG_NO(0), WithinRange) + RANGE(128, 255) + END_ARGUMENT_CONDITION + END_CASE + CASE // Other. + ARGUMENT_CONDITION(ARG_NO(0), OutOfRange) + RANGE('A', 'Z') + RANGE('a', 'z') + RANGE(128, 255) + END_ARGUMENT_CONDITION + RETURN_VALUE_CONDITION(WithinRange) + SINGLE_VALUE(0) + END_RETURN_VALUE_CONDITION + END_CASE + END_SUMMARY + SUMMARY(isascii, ARGUMENT_TYPES(IntTy), RETURN_TYPE(IntTy), + INVALIDATION_APPROACH(EvalCallAsPure)) + CASE // Is ASCII. + ARGUMENT_CONDITION(ARG_NO(0), WithinRange) + RANGE(0, 127) + END_ARGUMENT_CONDITION + RETURN_VALUE_CONDITION(OutOfRange) + SINGLE_VALUE(0) + END_RETURN_VALUE_CONDITION + END_CASE + CASE + ARGUMENT_CONDITION(ARG_NO(0), OutOfRange) + RANGE(0, 127) + END_ARGUMENT_CONDITION + RETURN_VALUE_CONDITION(WithinRange) + SINGLE_VALUE(0) + END_RETURN_VALUE_CONDITION + END_CASE + END_SUMMARY + SUMMARY(isblank, ARGUMENT_TYPES(IntTy), RETURN_TYPE(IntTy), + INVALIDATION_APPROACH(EvalCallAsPure)) + CASE + ARGUMENT_CONDITION(ARG_NO(0), WithinRange) + SINGLE_VALUE('\t') + SINGLE_VALUE(' ') + END_ARGUMENT_CONDITION + RETURN_VALUE_CONDITION(OutOfRange) + SINGLE_VALUE(0) + END_RETURN_VALUE_CONDITION + END_CASE + CASE + ARGUMENT_CONDITION(ARG_NO(0), OutOfRange) + SINGLE_VALUE('\t') + SINGLE_VALUE(' ') + END_ARGUMENT_CONDITION + RETURN_VALUE_CONDITION(WithinRange) + SINGLE_VALUE(0) + END_RETURN_VALUE_CONDITION + END_CASE + END_SUMMARY + SUMMARY(iscntrl, ARGUMENT_TYPES(IntTy), RETURN_TYPE(IntTy), + INVALIDATION_APPROACH(EvalCallAsPure)) + CASE // 0..31 or 127 + ARGUMENT_CONDITION(ARG_NO(0), WithinRange) + RANGE(0, 32) + SINGLE_VALUE(127) + END_ARGUMENT_CONDITION + RETURN_VALUE_CONDITION(OutOfRange) + SINGLE_VALUE(0) + END_RETURN_VALUE_CONDITION + END_CASE + CASE + ARGUMENT_CONDITION(ARG_NO(0), OutOfRange) + RANGE(0, 32) + SINGLE_VALUE(127) + END_ARGUMENT_CONDITION + RETURN_VALUE_CONDITION(WithinRange) + SINGLE_VALUE(0) + END_RETURN_VALUE_CONDITION + END_CASE + END_SUMMARY + SUMMARY(isdigit, ARGUMENT_TYPES(IntTy), RETURN_TYPE(IntTy), + INVALIDATION_APPROACH(EvalCallAsPure)) + CASE // Is a digit. + ARGUMENT_CONDITION(ARG_NO(0), WithinRange) + RANGE('0', '9') + END_ARGUMENT_CONDITION + RETURN_VALUE_CONDITION(OutOfRange) + SINGLE_VALUE(0) + END_RETURN_VALUE_CONDITION + END_CASE + CASE + ARGUMENT_CONDITION(ARG_NO(0), OutOfRange) + RANGE('0', '9') + END_ARGUMENT_CONDITION + RETURN_VALUE_CONDITION(WithinRange) + SINGLE_VALUE(0) + END_RETURN_VALUE_CONDITION + END_CASE + END_SUMMARY + SUMMARY(isgraph, ARGUMENT_TYPES(IntTy), RETURN_TYPE(IntTy), + INVALIDATION_APPROACH(EvalCallAsPure)) + CASE + ARGUMENT_CONDITION(ARG_NO(0), WithinRange) + RANGE(33, 126) + END_ARGUMENT_CONDITION + RETURN_VALUE_CONDITION(OutOfRange) + SINGLE_VALUE(0) + END_RETURN_VALUE_CONDITION + END_CASE + CASE + ARGUMENT_CONDITION(ARG_NO(0), OutOfRange) + RANGE(33, 126) + END_ARGUMENT_CONDITION + RETURN_VALUE_CONDITION(WithinRange) + SINGLE_VALUE(0) + END_RETURN_VALUE_CONDITION + END_CASE + END_SUMMARY + SUMMARY(islower, ARGUMENT_TYPES(IntTy), RETURN_TYPE(IntTy), + INVALIDATION_APPROACH(EvalCallAsPure)) + CASE // Is certainly lowercase. + ARGUMENT_CONDITION(ARG_NO(0), WithinRange) + RANGE('a', 'z') + END_ARGUMENT_CONDITION + RETURN_VALUE_CONDITION(OutOfRange) + SINGLE_VALUE(0) + END_RETURN_VALUE_CONDITION + END_CASE + CASE // Is ascii but not lowercase. + ARGUMENT_CONDITION(ARG_NO(0), WithinRange) + RANGE(0, 127) + END_ARGUMENT_CONDITION + ARGUMENT_CONDITION(ARG_NO(0), OutOfRange) + RANGE('a', 'z') + END_ARGUMENT_CONDITION + RETURN_VALUE_CONDITION(WithinRange) + SINGLE_VALUE(0) + END_RETURN_VALUE_CONDITION + END_CASE + CASE // The locale-specific range. + ARGUMENT_CONDITION(ARG_NO(0), WithinRange) + RANGE(128, 255) + END_ARGUMENT_CONDITION + END_CASE + CASE // Is not an unsigned char. + ARGUMENT_CONDITION(ARG_NO(0), OutOfRange) + RANGE(0, 255) + END_ARGUMENT_CONDITION + RETURN_VALUE_CONDITION(WithinRange) + SINGLE_VALUE(0) + END_RETURN_VALUE_CONDITION + END_CASE + END_SUMMARY + SUMMARY(isprint, ARGUMENT_TYPES(IntTy), RETURN_TYPE(IntTy), + INVALIDATION_APPROACH(EvalCallAsPure)) + CASE + ARGUMENT_CONDITION(ARG_NO(0), WithinRange) + RANGE(32, 126) + END_ARGUMENT_CONDITION + RETURN_VALUE_CONDITION(OutOfRange) + SINGLE_VALUE(0) + END_RETURN_VALUE_CONDITION + END_CASE + CASE + ARGUMENT_CONDITION(ARG_NO(0), OutOfRange) + RANGE(32, 126) + END_ARGUMENT_CONDITION + RETURN_VALUE_CONDITION(WithinRange) + SINGLE_VALUE(0) + END_RETURN_VALUE_CONDITION + END_CASE + END_SUMMARY + SUMMARY(ispunct, ARGUMENT_TYPES(IntTy), RETURN_TYPE(IntTy), + INVALIDATION_APPROACH(EvalCallAsPure)) + CASE + ARGUMENT_CONDITION(ARG_NO(0), WithinRange) + RANGE('!', '/') + RANGE(':', '@') + RANGE('[', '`') + RANGE('{', '~') + END_ARGUMENT_CONDITION + RETURN_VALUE_CONDITION(OutOfRange) + SINGLE_VALUE(0) + END_RETURN_VALUE_CONDITION + END_CASE + CASE + ARGUMENT_CONDITION(ARG_NO(0), OutOfRange) + RANGE('!', '/') + RANGE(':', '@') + RANGE('[', '`') + RANGE('{', '~') + END_ARGUMENT_CONDITION + RETURN_VALUE_CONDITION(WithinRange) + SINGLE_VALUE(0) + END_RETURN_VALUE_CONDITION + END_CASE + END_SUMMARY + SUMMARY(isspace, ARGUMENT_TYPES(IntTy), RETURN_TYPE(IntTy), + INVALIDATION_APPROACH(EvalCallAsPure)) + CASE // Space, '\f', '\n', '\r', '\t', '\v'. + ARGUMENT_CONDITION(ARG_NO(0), WithinRange) + RANGE(9, 13) + SINGLE_VALUE(' ') + END_ARGUMENT_CONDITION + RETURN_VALUE_CONDITION(OutOfRange) + SINGLE_VALUE(0) + END_RETURN_VALUE_CONDITION + END_CASE + CASE // The locale-specific range. + ARGUMENT_CONDITION(ARG_NO(0), WithinRange) + RANGE(128, 255) + END_ARGUMENT_CONDITION + END_CASE + CASE + ARGUMENT_CONDITION(ARG_NO(0), OutOfRange) + RANGE(9, 13) + SINGLE_VALUE(' ') + RANGE(128, 255) + END_ARGUMENT_CONDITION + RETURN_VALUE_CONDITION(WithinRange) + SINGLE_VALUE(0) + END_RETURN_VALUE_CONDITION + END_CASE + END_SUMMARY + SUMMARY(isupper, ARGUMENT_TYPES(IntTy), RETURN_TYPE (IntTy), + INVALIDATION_APPROACH(EvalCallAsPure)) + CASE // Is certainly uppercase. + ARGUMENT_CONDITION(ARG_NO(0), WithinRange) + RANGE('A', 'Z') + END_ARGUMENT_CONDITION + RETURN_VALUE_CONDITION(OutOfRange) + SINGLE_VALUE(0) + END_RETURN_VALUE_CONDITION + END_CASE + CASE // The locale-specific range. + ARGUMENT_CONDITION(ARG_NO(0), WithinRange) + RANGE(128, 255) + END_ARGUMENT_CONDITION + END_CASE + CASE // Other. + ARGUMENT_CONDITION(ARG_NO(0), OutOfRange) + RANGE('A', 'Z') RANGE(128, 255) + END_ARGUMENT_CONDITION + RETURN_VALUE_CONDITION(WithinRange) + SINGLE_VALUE(0) + END_RETURN_VALUE_CONDITION + END_CASE + END_SUMMARY + SUMMARY(isxdigit, ARGUMENT_TYPES(IntTy), RETURN_TYPE(IntTy), + INVALIDATION_APPROACH(EvalCallAsPure)) + CASE + ARGUMENT_CONDITION(ARG_NO(0), WithinRange) + RANGE('0', '9') + RANGE('A', 'F') + RANGE('a', 'f') + END_ARGUMENT_CONDITION + RETURN_VALUE_CONDITION(OutOfRange) + SINGLE_VALUE(0) + END_RETURN_VALUE_CONDITION + END_CASE + CASE + ARGUMENT_CONDITION(ARG_NO(0), OutOfRange) + RANGE('0', '9') + RANGE('A', 'F') + RANGE('a', 'f') + END_ARGUMENT_CONDITION + RETURN_VALUE_CONDITION(WithinRange) + SINGLE_VALUE(0) + END_RETURN_VALUE_CONDITION + END_CASE + END_SUMMARY + + // The getc() family of functions that returns either a char or an EOF. + SUMMARY(getc, ARGUMENT_TYPES(Irrelevant), RETURN_TYPE(IntTy), + INVALIDATION_APPROACH(NoEvalCall)) + CASE // FIXME: EOF is assumed to be defined as -1. + RETURN_VALUE_CONDITION(WithinRange) + RANGE(-1, 255) + END_RETURN_VALUE_CONDITION + END_CASE + END_SUMMARY + SUMMARY(fgetc, ARGUMENT_TYPES(Irrelevant), RETURN_TYPE(IntTy), + INVALIDATION_APPROACH(NoEvalCall)) + CASE // FIXME: EOF is assumed to be defined as -1. + RETURN_VALUE_CONDITION(WithinRange) + RANGE(-1, 255) + END_RETURN_VALUE_CONDITION + END_CASE + END_SUMMARY + SUMMARY(getchar, ARGUMENT_TYPES(), RETURN_TYPE(IntTy), + INVALIDATION_APPROACH(NoEvalCall)) + CASE // FIXME: EOF is assumed to be defined as -1. + RETURN_VALUE_CONDITION(WithinRange) + RANGE(-1, 255) + END_RETURN_VALUE_CONDITION + END_CASE + END_SUMMARY + + // read()-like functions that never return more than buffer size. + // We are not sure how ssize_t is defined on every platform, so we provide + // three variants that should cover common cases. + SUMMARY_WITH_VARIANTS(read) + VARIANT(ARGUMENT_TYPES(Irrelevant, Irrelevant, SizeTy), + RETURN_TYPE(IntTy), INVALIDATION_APPROACH(NoEvalCall)) + CASE + RETURN_VALUE_CONDITION(ComparesToArgument) + IS_LESS_THAN(ARG_NO(2)) + END_RETURN_VALUE_CONDITION + RETURN_VALUE_CONDITION(WithinRange) + RANGE(-1, IntMax) + END_RETURN_VALUE_CONDITION + END_CASE + END_VARIANT + VARIANT(ARGUMENT_TYPES(Irrelevant, Irrelevant, SizeTy), + RETURN_TYPE(LongTy), INVALIDATION_APPROACH(NoEvalCall)) + CASE + RETURN_VALUE_CONDITION(ComparesToArgument) + IS_LESS_THAN(ARG_NO(2)) + END_RETURN_VALUE_CONDITION + RETURN_VALUE_CONDITION(WithinRange) + RANGE(-1, LongMax) + END_RETURN_VALUE_CONDITION + END_CASE + END_VARIANT + VARIANT(ARGUMENT_TYPES(Irrelevant, Irrelevant, SizeTy), + RETURN_TYPE(LongLongTy), INVALIDATION_APPROACH(NoEvalCall)) + CASE + RETURN_VALUE_CONDITION(ComparesToArgument) + IS_LESS_THAN(ARG_NO(2)) + END_RETURN_VALUE_CONDITION + RETURN_VALUE_CONDITION(WithinRange) + RANGE(-1, LongLongMax) + END_RETURN_VALUE_CONDITION + END_CASE + END_VARIANT + END_SUMMARY_WITH_VARIANTS + SUMMARY_WITH_VARIANTS(write) + // Again, due to elusive nature of ssize_t, we have duplicate + // our summaries to cover different variants. + VARIANT(ARGUMENT_TYPES(Irrelevant, Irrelevant, SizeTy), + RETURN_TYPE(IntTy), INVALIDATION_APPROACH(NoEvalCall)) + CASE + RETURN_VALUE_CONDITION(ComparesToArgument) + IS_LESS_THAN(ARG_NO(2)) + END_RETURN_VALUE_CONDITION + RETURN_VALUE_CONDITION(WithinRange) + RANGE(-1, IntMax) + END_RETURN_VALUE_CONDITION + END_CASE + END_VARIANT + VARIANT(ARGUMENT_TYPES(Irrelevant, Irrelevant, SizeTy), + RETURN_TYPE(LongTy), INVALIDATION_APPROACH(NoEvalCall)) + CASE + RETURN_VALUE_CONDITION(ComparesToArgument) + IS_LESS_THAN(ARG_NO(2)) + END_RETURN_VALUE_CONDITION + RETURN_VALUE_CONDITION(WithinRange) + RANGE(-1, LongMax) + END_RETURN_VALUE_CONDITION + END_CASE + END_VARIANT + VARIANT(ARGUMENT_TYPES(Irrelevant, Irrelevant, SizeTy), + RETURN_TYPE(LongLongTy), INVALIDATION_APPROACH(NoEvalCall)) + CASE + RETURN_VALUE_CONDITION(ComparesToArgument) + IS_LESS_THAN(ARG_NO(2)) + END_RETURN_VALUE_CONDITION + RETURN_VALUE_CONDITION(WithinRange) + RANGE(-1, LongLongMax) + END_RETURN_VALUE_CONDITION + END_CASE + END_VARIANT + END_SUMMARY_WITH_VARIANTS + SUMMARY(fread, + ARGUMENT_TYPES(Irrelevant, Irrelevant, SizeTy, Irrelevant), + RETURN_TYPE(SizeTy), INVALIDATION_APPROACH(NoEvalCall)) + CASE + RETURN_VALUE_CONDITION(ComparesToArgument) + IS_LESS_THAN(ARG_NO(2)) + END_RETURN_VALUE_CONDITION + END_CASE + END_SUMMARY + SUMMARY(fwrite, + ARGUMENT_TYPES(Irrelevant, Irrelevant, SizeTy, Irrelevant), + RETURN_TYPE(SizeTy), INVALIDATION_APPROACH(NoEvalCall)) + CASE + RETURN_VALUE_CONDITION(ComparesToArgument) + IS_LESS_THAN(ARG_NO(2)) + END_RETURN_VALUE_CONDITION + END_CASE + END_SUMMARY + + // getline()-like functions either fail or read at least the delimiter. + SUMMARY_WITH_VARIANTS(getline) + VARIANT(ARGUMENT_TYPES(Irrelevant, Irrelevant, Irrelevant), + RETURN_TYPE(IntTy), INVALIDATION_APPROACH(NoEvalCall)) + CASE + RETURN_VALUE_CONDITION(WithinRange) + SINGLE_VALUE(-1) + RANGE(1, IntMax) + END_RETURN_VALUE_CONDITION + END_CASE + END_VARIANT + VARIANT(ARGUMENT_TYPES(Irrelevant, Irrelevant, Irrelevant), + RETURN_TYPE(LongTy), INVALIDATION_APPROACH(NoEvalCall)) + CASE + RETURN_VALUE_CONDITION(WithinRange) + SINGLE_VALUE(-1) + RANGE(1, LongMax) + END_RETURN_VALUE_CONDITION + END_CASE + END_VARIANT + VARIANT(ARGUMENT_TYPES(Irrelevant, Irrelevant, Irrelevant), + RETURN_TYPE(LongLongTy), INVALIDATION_APPROACH(NoEvalCall)) + CASE + RETURN_VALUE_CONDITION(WithinRange) + SINGLE_VALUE(-1) + RANGE(1, LongLongMax) + END_RETURN_VALUE_CONDITION + END_CASE + END_VARIANT + END_SUMMARY_WITH_VARIANTS + SUMMARY_WITH_VARIANTS(getdelim) + VARIANT(ARGUMENT_TYPES(Irrelevant, Irrelevant, Irrelevant, Irrelevant), + RETURN_TYPE(IntTy), INVALIDATION_APPROACH(NoEvalCall)) + CASE + RETURN_VALUE_CONDITION(WithinRange) + SINGLE_VALUE(-1) + RANGE(1, IntMax) + END_RETURN_VALUE_CONDITION + END_CASE + END_VARIANT + VARIANT(ARGUMENT_TYPES(Irrelevant, Irrelevant, Irrelevant, Irrelevant), + RETURN_TYPE(LongTy), INVALIDATION_APPROACH(NoEvalCall)) + CASE + RETURN_VALUE_CONDITION(WithinRange) + SINGLE_VALUE(-1) + RANGE(1, LongMax) + END_RETURN_VALUE_CONDITION + END_CASE + END_VARIANT + VARIANT(ARGUMENT_TYPES(Irrelevant, Irrelevant, Irrelevant, Irrelevant), + RETURN_TYPE(LongLongTy), INVALIDATION_APPROACH(NoEvalCall)) + CASE + RETURN_VALUE_CONDITION(WithinRange) + SINGLE_VALUE(-1) + RANGE(1, LongLongMax) + END_RETURN_VALUE_CONDITION + END_CASE + END_VARIANT + END_SUMMARY_WITH_VARIANTS + }; +} + +void ento::registerStdCLibraryFunctionsChecker(CheckerManager &mgr) { + // If this checker grows large enough to support C++, Objective-C, or other + // standard libraries, we could use multiple register...Checker() functions, + // which would register various checkers with the help of the same Checker + // class, turning on different function summaries. + mgr.registerChecker<StdLibraryFunctionsChecker>(); +} + +bool ento::shouldRegisterStdCLibraryFunctionsChecker(const LangOptions &LO) { + return true; +} |