1 //===-- SpecialCaseList.cpp - special case list for sanitizers ------------===// 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 // This is a utility class for instrumentation passes (like AddressSanitizer 10 // or ThreadSanitizer) to avoid instrumenting some functions or global 11 // variables, or to instrument some functions or global variables in a specific 12 // way, based on a user-supplied list. 13 // 14 //===----------------------------------------------------------------------===// 15 16 #include "llvm/Support/SpecialCaseList.h" 17 #include "llvm/ADT/SmallVector.h" 18 #include "llvm/ADT/StringExtras.h" 19 #include "llvm/Support/MemoryBuffer.h" 20 #include "llvm/Support/Regex.h" 21 #include "llvm/Support/VirtualFileSystem.h" 22 #include <string> 23 #include <system_error> 24 #include <utility> 25 26 #include <stdio.h> 27 namespace llvm { 28 29 bool SpecialCaseList::Matcher::insert(std::string Regexp, 30 unsigned LineNumber, 31 std::string &REError) { 32 if (Regexp.empty()) { 33 REError = "Supplied regexp was blank"; 34 return false; 35 } 36 37 if (Regex::isLiteralERE(Regexp)) { 38 Strings[Regexp] = LineNumber; 39 return true; 40 } 41 Trigrams.insert(Regexp); 42 43 // Replace * with .* 44 for (size_t pos = 0; (pos = Regexp.find('*', pos)) != std::string::npos; 45 pos += strlen(".*")) { 46 Regexp.replace(pos, strlen("*"), ".*"); 47 } 48 49 Regexp = (Twine("^(") + StringRef(Regexp) + ")$").str(); 50 51 // Check that the regexp is valid. 52 Regex CheckRE(Regexp); 53 if (!CheckRE.isValid(REError)) 54 return false; 55 56 RegExes.emplace_back( 57 std::make_pair(std::make_unique<Regex>(std::move(CheckRE)), LineNumber)); 58 return true; 59 } 60 61 unsigned SpecialCaseList::Matcher::match(StringRef Query) const { 62 auto It = Strings.find(Query); 63 if (It != Strings.end()) 64 return It->second; 65 if (Trigrams.isDefinitelyOut(Query)) 66 return false; 67 for (auto& RegExKV : RegExes) 68 if (RegExKV.first->match(Query)) 69 return RegExKV.second; 70 return 0; 71 } 72 73 std::unique_ptr<SpecialCaseList> 74 SpecialCaseList::create(const std::vector<std::string> &Paths, 75 llvm::vfs::FileSystem &FS, std::string &Error) { 76 std::unique_ptr<SpecialCaseList> SCL(new SpecialCaseList()); 77 if (SCL->createInternal(Paths, FS, Error)) 78 return SCL; 79 return nullptr; 80 } 81 82 std::unique_ptr<SpecialCaseList> SpecialCaseList::create(const MemoryBuffer *MB, 83 std::string &Error) { 84 std::unique_ptr<SpecialCaseList> SCL(new SpecialCaseList()); 85 if (SCL->createInternal(MB, Error)) 86 return SCL; 87 return nullptr; 88 } 89 90 std::unique_ptr<SpecialCaseList> 91 SpecialCaseList::createOrDie(const std::vector<std::string> &Paths, 92 llvm::vfs::FileSystem &FS) { 93 std::string Error; 94 if (auto SCL = create(Paths, FS, Error)) 95 return SCL; 96 report_fatal_error(Error); 97 } 98 99 bool SpecialCaseList::createInternal(const std::vector<std::string> &Paths, 100 vfs::FileSystem &VFS, std::string &Error) { 101 StringMap<size_t> Sections; 102 for (const auto &Path : Paths) { 103 ErrorOr<std::unique_ptr<MemoryBuffer>> FileOrErr = 104 VFS.getBufferForFile(Path); 105 if (std::error_code EC = FileOrErr.getError()) { 106 Error = (Twine("can't open file '") + Path + "': " + EC.message()).str(); 107 return false; 108 } 109 std::string ParseError; 110 if (!parse(FileOrErr.get().get(), Sections, ParseError)) { 111 Error = (Twine("error parsing file '") + Path + "': " + ParseError).str(); 112 return false; 113 } 114 } 115 return true; 116 } 117 118 bool SpecialCaseList::createInternal(const MemoryBuffer *MB, 119 std::string &Error) { 120 StringMap<size_t> Sections; 121 if (!parse(MB, Sections, Error)) 122 return false; 123 return true; 124 } 125 126 bool SpecialCaseList::parse(const MemoryBuffer *MB, 127 StringMap<size_t> &SectionsMap, 128 std::string &Error) { 129 // Iterate through each line in the exclusion list file. 130 SmallVector<StringRef, 16> Lines; 131 MB->getBuffer().split(Lines, '\n'); 132 133 unsigned LineNo = 1; 134 StringRef Section = "*"; 135 136 for (auto I = Lines.begin(), E = Lines.end(); I != E; ++I, ++LineNo) { 137 *I = I->trim(); 138 // Ignore empty lines and lines starting with "#" 139 if (I->empty() || I->startswith("#")) 140 continue; 141 142 // Save section names 143 if (I->startswith("[")) { 144 if (!I->endswith("]")) { 145 Error = (Twine("malformed section header on line ") + Twine(LineNo) + 146 ": " + *I).str(); 147 return false; 148 } 149 150 Section = I->slice(1, I->size() - 1); 151 152 std::string REError; 153 Regex CheckRE(Section); 154 if (!CheckRE.isValid(REError)) { 155 Error = 156 (Twine("malformed regex for section ") + Section + ": '" + REError) 157 .str(); 158 return false; 159 } 160 161 continue; 162 } 163 164 // Get our prefix and unparsed regexp. 165 std::pair<StringRef, StringRef> SplitLine = I->split(":"); 166 StringRef Prefix = SplitLine.first; 167 if (SplitLine.second.empty()) { 168 // Missing ':' in the line. 169 Error = (Twine("malformed line ") + Twine(LineNo) + ": '" + 170 SplitLine.first + "'").str(); 171 return false; 172 } 173 174 std::pair<StringRef, StringRef> SplitRegexp = SplitLine.second.split("="); 175 std::string Regexp = std::string(SplitRegexp.first); 176 StringRef Category = SplitRegexp.second; 177 178 // Create this section if it has not been seen before. 179 if (SectionsMap.find(Section) == SectionsMap.end()) { 180 std::unique_ptr<Matcher> M = std::make_unique<Matcher>(); 181 std::string REError; 182 if (!M->insert(std::string(Section), LineNo, REError)) { 183 Error = (Twine("malformed section ") + Section + ": '" + REError).str(); 184 return false; 185 } 186 187 SectionsMap[Section] = Sections.size(); 188 Sections.emplace_back(std::move(M)); 189 } 190 191 auto &Entry = Sections[SectionsMap[Section]].Entries[Prefix][Category]; 192 std::string REError; 193 if (!Entry.insert(std::move(Regexp), LineNo, REError)) { 194 Error = (Twine("malformed regex in line ") + Twine(LineNo) + ": '" + 195 SplitLine.second + "': " + REError).str(); 196 return false; 197 } 198 } 199 return true; 200 } 201 202 SpecialCaseList::~SpecialCaseList() {} 203 204 bool SpecialCaseList::inSection(StringRef Section, StringRef Prefix, 205 StringRef Query, StringRef Category) const { 206 return inSectionBlame(Section, Prefix, Query, Category); 207 } 208 209 unsigned SpecialCaseList::inSectionBlame(StringRef Section, StringRef Prefix, 210 StringRef Query, 211 StringRef Category) const { 212 for (auto &SectionIter : Sections) 213 if (SectionIter.SectionMatcher->match(Section)) { 214 unsigned Blame = 215 inSectionBlame(SectionIter.Entries, Prefix, Query, Category); 216 if (Blame) 217 return Blame; 218 } 219 return 0; 220 } 221 222 unsigned SpecialCaseList::inSectionBlame(const SectionEntries &Entries, 223 StringRef Prefix, StringRef Query, 224 StringRef Category) const { 225 SectionEntries::const_iterator I = Entries.find(Prefix); 226 if (I == Entries.end()) return 0; 227 StringMap<Matcher>::const_iterator II = I->second.find(Category); 228 if (II == I->second.end()) return 0; 229 230 return II->getValue().match(Query); 231 } 232 233 } // namespace llvm 234