//===-- SpecialCaseList.h - special case list for sanitizers ----*- 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 is a utility class used to parse user-provided text files with
// "special case lists" for code sanitizers. Such files are used to
// define an "ABI list" for DataFlowSanitizer and allow/exclusion lists for
// sanitizers like AddressSanitizer or UndefinedBehaviorSanitizer.
//
// Empty lines and lines starting with "#" are ignored. Sections are defined
// using a '[section_name]' header and can be used to specify sanitizers the
// entries below it apply to. Section names are regular expressions, and
// entries without a section header match all sections (e.g. an '[*]' header
// is assumed.)
// The remaining lines should have the form:
// prefix:wildcard_expression[=category]
// If category is not specified, it is assumed to be empty string.
// Definitions of "prefix" and "category" are sanitizer-specific. For example,
// sanitizer exclusion support prefixes "src", "mainfile", "fun" and "global".
// Wildcard expressions define, respectively, source files, main files,
// functions or globals which shouldn't be instrumented.
// Examples of categories:
// "functional": used in DFSan to list functions with pure functional
// semantics.
// "init": used in ASan exclusion list to disable initialization-order bugs
// detection for certain globals or source files.
// Full special case list file example:
// ---
// [address]
// # Excluded items:
// fun:*_ZN4base6subtle*
// global:*global_with_bad_access_or_initialization*
// global:*global_with_initialization_issues*=init
// type:*Namespace::ClassName*=init
// src:file_with_tricky_code.cc
// src:ignore-global-initializers-issues.cc=init
// mainfile:main_file.cc
//
// [dataflow]
// # Functions with pure functional semantics:
// fun:cos=functional
// fun:sin=functional
// ---
// Note that the wild card is in fact an llvm::Regex, but * is automatically
// replaced with .*
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_SUPPORT_SPECIALCASELIST_H
#define LLVM_SUPPORT_SPECIALCASELIST_H
#include "llvm/ADT/StringMap.h"
#include "llvm/Support/Regex.h"
#include "llvm/Support/TrigramIndex.h"
#include <memory>
#include <string>
#include <vector>
namespace llvm {
class MemoryBuffer;
class StringRef;
namespace vfs {
class FileSystem;
}
class SpecialCaseList {
public:
/// Parses the special case list entries from files. On failure, returns
/// 0 and writes an error message to string.
static std::unique_ptr<SpecialCaseList>
create(const std::vector<std::string> &Paths, llvm::vfs::FileSystem &FS,
std::string &Error);
/// Parses the special case list from a memory buffer. On failure, returns
/// 0 and writes an error message to string.
static std::unique_ptr<SpecialCaseList> create(const MemoryBuffer *MB,
std::string &Error);
/// Parses the special case list entries from files. On failure, reports a
/// fatal error.
static std::unique_ptr<SpecialCaseList>
createOrDie(const std::vector<std::string> &Paths, llvm::vfs::FileSystem &FS);
~SpecialCaseList();
/// Returns true, if special case list contains a line
/// \code
/// @Prefix:<E>=@Category
/// \endcode
/// where @Query satisfies wildcard expression <E> in a given @Section.
bool inSection(StringRef Section, StringRef Prefix, StringRef Query,
StringRef Category = StringRef()) const;
/// Returns the line number corresponding to the special case list entry if
/// the special case list contains a line
/// \code
/// @Prefix:<E>=@Category
/// \endcode
/// where @Query satisfies wildcard expression <E> in a given @Section.
/// Returns zero if there is no exclusion entry corresponding to this
/// expression.
unsigned inSectionBlame(StringRef Section, StringRef Prefix, StringRef Query,
StringRef Category = StringRef()) const;
protected:
// Implementations of the create*() functions that can also be used by derived
// classes.
bool createInternal(const std::vector<std::string> &Paths,
vfs::FileSystem &VFS, std::string &Error);
bool createInternal(const MemoryBuffer *MB, std::string &Error);
SpecialCaseList() = default;
SpecialCaseList(SpecialCaseList const &) = delete;
SpecialCaseList &operator=(SpecialCaseList const &) = delete;
/// Represents a set of regular expressions. Regular expressions which are
/// "literal" (i.e. no regex metacharacters) are stored in Strings. The
/// reason for doing so is efficiency; StringMap is much faster at matching
/// literal strings than Regex.
class Matcher {
public:
bool insert(std::string Regexp, unsigned LineNumber, std::string &REError);
// Returns the line number in the source file that this query matches to.
// Returns zero if no match is found.
unsigned match(StringRef Query) const;
private:
StringMap<unsigned> Strings;
TrigramIndex Trigrams;
std::vector<std::pair<std::unique_ptr<Regex>, unsigned>> RegExes;
};
using SectionEntries = StringMap<StringMap<Matcher>>;
struct Section {
Section(std::unique_ptr<Matcher> M) : SectionMatcher(std::move(M)){};
std::unique_ptr<Matcher> SectionMatcher;
SectionEntries Entries;
};
std::vector<Section> Sections;
/// Parses just-constructed SpecialCaseList entries from a memory buffer.
bool parse(const MemoryBuffer *MB, StringMap<size_t> &SectionsMap,
std::string &Error);
// Helper method for derived classes to search by Prefix, Query, and Category
// once they have already resolved a section entry.
unsigned inSectionBlame(const SectionEntries &Entries, StringRef Prefix,
StringRef Query, StringRef Category) const;
};
} // namespace llvm
#endif // LLVM_SUPPORT_SPECIALCASELIST_H