llvm/lib/Support/SpecialCaseList.cpp

   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