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| 1 | +//===- CallDescription.h - function/method call matching --*- C++ -*-===// |
| 2 | +// |
| 3 | +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| 4 | +// See https://llvm.org/LICENSE.txt for license information. |
| 5 | +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| 6 | +// |
| 7 | +//===----------------------------------------------------------------------===// |
| 8 | +// |
| 9 | +/// \file This file defines a generic mechanism for matching for function and |
| 10 | +/// method calls of C, C++, and Objective-C languages. Instances of these |
| 11 | +/// classes are frequently used together with the CallEvent classes. |
| 12 | +// |
| 13 | +//===----------------------------------------------------------------------===// |
| 14 | + |
| 15 | +#ifndef LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_CALLDESCRIPTION_H |
| 16 | +#define LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_CALLDESCRIPTION_H |
| 17 | + |
| 18 | +#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h" |
| 19 | +#include "llvm/ADT/ArrayRef.h" |
| 20 | +#include "llvm/ADT/Optional.h" |
| 21 | +#include "llvm/Support/Compiler.h" |
| 22 | +#include <vector> |
| 23 | + |
| 24 | +namespace clang { |
| 25 | +class IdentifierInfo; |
| 26 | +} // namespace clang |
| 27 | + |
| 28 | +namespace clang { |
| 29 | +namespace ento { |
| 30 | + |
| 31 | +enum CallDescriptionFlags : unsigned { |
| 32 | + CDF_None = 0, |
| 33 | + |
| 34 | + /// Describes a C standard function that is sometimes implemented as a macro |
| 35 | + /// that expands to a compiler builtin with some __builtin prefix. |
| 36 | + /// The builtin may as well have a few extra arguments on top of the requested |
| 37 | + /// number of arguments. |
| 38 | + CDF_MaybeBuiltin = 1 << 0, |
| 39 | +}; |
| 40 | + |
| 41 | +/// This class represents a description of a function call using the number of |
| 42 | +/// arguments and the name of the function. |
| 43 | +class CallDescription { |
| 44 | + friend class CallEvent; |
| 45 | + using MaybeCount = Optional<unsigned>; |
| 46 | + |
| 47 | + mutable Optional<const IdentifierInfo *> II; |
| 48 | + // The list of the qualified names used to identify the specified CallEvent, |
| 49 | + // e.g. "{a, b}" represent the qualified names, like "a::b". |
| 50 | + std::vector<std::string> QualifiedName; |
| 51 | + MaybeCount RequiredArgs; |
| 52 | + MaybeCount RequiredParams; |
| 53 | + int Flags; |
| 54 | + |
| 55 | +public: |
| 56 | + /// Constructs a CallDescription object. |
| 57 | + /// |
| 58 | + /// @param QualifiedName The list of the name qualifiers of the function that |
| 59 | + /// will be matched. The user is allowed to skip any of the qualifiers. |
| 60 | + /// For example, {"std", "basic_string", "c_str"} would match both |
| 61 | + /// std::basic_string<...>::c_str() and std::__1::basic_string<...>::c_str(). |
| 62 | + /// |
| 63 | + /// @param RequiredArgs The number of arguments that is expected to match a |
| 64 | + /// call. Omit this parameter to match every occurrence of call with a given |
| 65 | + /// name regardless the number of arguments. |
| 66 | + CallDescription(CallDescriptionFlags Flags, |
| 67 | + ArrayRef<const char *> QualifiedName, |
| 68 | + MaybeCount RequiredArgs = None, |
| 69 | + MaybeCount RequiredParams = None); |
| 70 | + |
| 71 | + /// Construct a CallDescription with default flags. |
| 72 | + CallDescription(ArrayRef<const char *> QualifiedName, |
| 73 | + MaybeCount RequiredArgs = None, |
| 74 | + MaybeCount RequiredParams = None); |
| 75 | + |
| 76 | + CallDescription(std::nullptr_t) = delete; |
| 77 | + |
| 78 | + /// Get the name of the function that this object matches. |
| 79 | + StringRef getFunctionName() const { return QualifiedName.back(); } |
| 80 | + |
| 81 | + /// Get the qualified name parts in reversed order. |
| 82 | + /// E.g. { "std", "vector", "data" } -> "vector", "std" |
| 83 | + auto begin_qualified_name_parts() const { |
| 84 | + return std::next(QualifiedName.rbegin()); |
| 85 | + } |
| 86 | + auto end_qualified_name_parts() const { return QualifiedName.rend(); } |
| 87 | + |
| 88 | + /// It's false, if and only if we expect a single identifier, such as |
| 89 | + /// `getenv`. It's true for `std::swap`, or `my::detail::container::data`. |
| 90 | + bool hasQualifiedNameParts() const { return QualifiedName.size() > 1; } |
| 91 | + |
| 92 | + /// @name Matching CallDescriptions against a CallEvent |
| 93 | + /// @{ |
| 94 | + |
| 95 | + /// Returns true if the CallEvent is a call to a function that matches |
| 96 | + /// the CallDescription. |
| 97 | + /// |
| 98 | + /// \note This function is not intended to be used to match Obj-C method |
| 99 | + /// calls. |
| 100 | + bool matches(const CallEvent &Call) const; |
| 101 | + |
| 102 | + /// Returns true whether the CallEvent matches on any of the CallDescriptions |
| 103 | + /// supplied. |
| 104 | + /// |
| 105 | + /// \note This function is not intended to be used to match Obj-C method |
| 106 | + /// calls. |
| 107 | + friend bool matchesAny(const CallEvent &Call, const CallDescription &CD1) { |
| 108 | + return CD1.matches(Call); |
| 109 | + } |
| 110 | + |
| 111 | + /// \copydoc clang::ento::matchesAny(const CallEvent &, const CallDescription &) |
| 112 | + template <typename... Ts> |
| 113 | + friend bool matchesAny(const CallEvent &Call, const CallDescription &CD1, |
| 114 | + const Ts &...CDs) { |
| 115 | + return CD1.matches(Call) || matchesAny(Call, CDs...); |
| 116 | + } |
| 117 | + /// @} |
| 118 | +}; |
| 119 | + |
| 120 | +/// An immutable map from CallDescriptions to arbitrary data. Provides a unified |
| 121 | +/// way for checkers to react on function calls. |
| 122 | +template <typename T> class CallDescriptionMap { |
| 123 | + friend class CallDescriptionSet; |
| 124 | + |
| 125 | + // Some call descriptions aren't easily hashable (eg., the ones with qualified |
| 126 | + // names in which some sections are omitted), so let's put them |
| 127 | + // in a simple vector and use linear lookup. |
| 128 | + // TODO: Implement an actual map for fast lookup for "hashable" call |
| 129 | + // descriptions (eg., the ones for C functions that just match the name). |
| 130 | + std::vector<std::pair<CallDescription, T>> LinearMap; |
| 131 | + |
| 132 | +public: |
| 133 | + CallDescriptionMap( |
| 134 | + std::initializer_list<std::pair<CallDescription, T>> &&List) |
| 135 | + : LinearMap(List) {} |
| 136 | + |
| 137 | + template <typename InputIt> |
| 138 | + CallDescriptionMap(InputIt First, InputIt Last) : LinearMap(First, Last) {} |
| 139 | + |
| 140 | + ~CallDescriptionMap() = default; |
| 141 | + |
| 142 | + // These maps are usually stored once per checker, so let's make sure |
| 143 | + // we don't do redundant copies. |
| 144 | + CallDescriptionMap(const CallDescriptionMap &) = delete; |
| 145 | + CallDescriptionMap &operator=(const CallDescription &) = delete; |
| 146 | + |
| 147 | + CallDescriptionMap(CallDescriptionMap &&) = default; |
| 148 | + CallDescriptionMap &operator=(CallDescriptionMap &&) = default; |
| 149 | + |
| 150 | + LLVM_NODISCARD const T *lookup(const CallEvent &Call) const { |
| 151 | + // Slow path: linear lookup. |
| 152 | + // TODO: Implement some sort of fast path. |
| 153 | + for (const std::pair<CallDescription, T> &I : LinearMap) |
| 154 | + if (I.first.matches(Call)) |
| 155 | + return &I.second; |
| 156 | + |
| 157 | + return nullptr; |
| 158 | + } |
| 159 | +}; |
| 160 | + |
| 161 | +/// An immutable set of CallDescriptions. |
| 162 | +/// Checkers can efficiently decide if a given CallEvent matches any |
| 163 | +/// CallDescription in the set. |
| 164 | +class CallDescriptionSet { |
| 165 | + CallDescriptionMap<bool /*unused*/> Impl = {}; |
| 166 | + |
| 167 | +public: |
| 168 | + CallDescriptionSet(std::initializer_list<CallDescription> &&List); |
| 169 | + |
| 170 | + CallDescriptionSet(const CallDescriptionSet &) = delete; |
| 171 | + CallDescriptionSet &operator=(const CallDescription &) = delete; |
| 172 | + |
| 173 | + LLVM_NODISCARD bool contains(const CallEvent &Call) const; |
| 174 | +}; |
| 175 | + |
| 176 | +} // namespace ento |
| 177 | +} // namespace clang |
| 178 | + |
| 179 | +#endif // LLVM_CLANG_STATICANALYZER_CORE_PATHSENSITIVE_CALLDESCRIPTION_H |
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