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/Support/LineIterator.h"
  18 #include "llvm/Support/MemoryBuffer.h"
  19 #include "llvm/Support/VirtualFileSystem.h"
  20 #include <stdio.h>
  21 #include <string>
  22 #include <system_error>
  23 #include <utility>
  24
  25 namespace llvm {
  26
  27 Error SpecialCaseList::Matcher::insert(StringRef Pattern, unsigned LineNumber,
  28                                        bool UseGlobs) {
  29   if (Pattern.empty())
  30     return createStringError(errc::invalid_argument,
  31                              Twine("Supplied ") +
  32                                  (UseGlobs ? "glob" : "regex") + " was blank");
  33
  34   if (!UseGlobs) {
  35     // Replace * with .*
  36     auto Regexp = Pattern.str();
  37     for (size_t pos = 0; (pos = Regexp.find('*', pos)) != std::string::npos;
  38          pos += strlen(".*")) {
  39       Regexp.replace(pos, strlen("*"), ".*");
  40     }
  41
  42     Regexp = (Twine("^(") + StringRef(Regexp) + ")$").str();
  43
  44     // Check that the regexp is valid.
  45     Regex CheckRE(Regexp);
  46     std::string REError;
  47     if (!CheckRE.isValid(REError))
  48       return createStringError(errc::invalid_argument, REError);
  49
  50     RegExes.emplace_back(std::make_pair(
  51         std::make_unique<Regex>(std::move(CheckRE)), LineNumber));
  52
  53     return Error::success();
  54   }
  55
  56   auto [It, DidEmplace] = Globs.try_emplace(Pattern);
  57   if (DidEmplace) {
  58     // We must be sure to use the string in the map rather than the provided
  59     // reference which could be destroyed before match() is called
  60     Pattern = It->getKey();
  61     auto &Pair = It->getValue();
  62     if (auto Err = GlobPattern::create(Pattern, /*MaxSubPatterns=*/1024)
  63                        .moveInto(Pair.first))
  64       return Err;
  65     Pair.second = LineNumber;
  66   }
  67   return Error::success();
  68 }
  69
  70 unsigned SpecialCaseList::Matcher::match(StringRef Query) const {
  71   for (const auto &[Pattern, Pair] : Globs)
  72     if (Pair.first.match(Query))
  73       return Pair.second;
  74   for (const auto &[Regex, LineNumber] : RegExes)
  75     if (Regex->match(Query))
  76       return LineNumber;
  77   return 0;
  78 }
  79
  80 // TODO: Refactor this to return Expected<...>
  81 std::unique_ptr<SpecialCaseList>
  82 SpecialCaseList::create(const std::vector<std::string> &Paths,
  83                         llvm::vfs::FileSystem &FS, std::string &Error) {
  84   std::unique_ptr<SpecialCaseList> SCL(new SpecialCaseList());
  85   if (SCL->createInternal(Paths, FS, Error))
  86     return SCL;
  87   return nullptr;
  88 }
  89
  90 std::unique_ptr<SpecialCaseList> SpecialCaseList::create(const MemoryBuffer *MB,
  91                                                          std::string &Error) {
  92   std::unique_ptr<SpecialCaseList> SCL(new SpecialCaseList());
  93   if (SCL->createInternal(MB, Error))
  94     return SCL;
  95   return nullptr;
  96 }
  97
  98 std::unique_ptr<SpecialCaseList>
  99 SpecialCaseList::createOrDie(const std::vector<std::string> &Paths,
 100                              llvm::vfs::FileSystem &FS) {
 101   std::string Error;
 102   if (auto SCL = create(Paths, FS, Error))
 103     return SCL;
 104   report_fatal_error(Twine(Error));
 105 }
 106
 107 bool SpecialCaseList::createInternal(const std::vector<std::string> &Paths,
 108                                      vfs::FileSystem &VFS, std::string &Error) {
 109   for (const auto &Path : Paths) {
 110     ErrorOr<std::unique_ptr<MemoryBuffer>> FileOrErr =
 111         VFS.getBufferForFile(Path);
 112     if (std::error_code EC = FileOrErr.getError()) {
 113       Error = (Twine("can't open file '") + Path + "': " + EC.message()).str();
 114       return false;
 115     }
 116     std::string ParseError;
 117     if (!parse(FileOrErr.get().get(), ParseError)) {
 118       Error = (Twine("error parsing file '") + Path + "': " + ParseError).str();
 119       return false;
 120     }
 121   }
 122   return true;
 123 }
 124
 125 bool SpecialCaseList::createInternal(const MemoryBuffer *MB,
 126                                      std::string &Error) {
 127   if (!parse(MB, Error))
 128     return false;
 129   return true;
 130 }
 131
 132 Expected<SpecialCaseList::Section *>
 133 SpecialCaseList::addSection(StringRef SectionStr, unsigned LineNo,
 134                             bool UseGlobs) {
 135   auto [It, DidEmplace] = Sections.try_emplace(SectionStr);
 136   auto &Section = It->getValue();
 137   if (DidEmplace)
 138     if (auto Err = Section.SectionMatcher->insert(SectionStr, LineNo, UseGlobs))
 139       return createStringError(errc::invalid_argument,
 140                                "malformed section at line " + Twine(LineNo) +
 141                                    ": '" + SectionStr +
 142                                    "': " + toString(std::move(Err)));
 143   return &Section;
 144 }
 145
 146 bool SpecialCaseList::parse(const MemoryBuffer *MB, std::string &Error) {
 147   Section *CurrentSection;
 148   if (auto Err = addSection("*", 1).moveInto(CurrentSection)) {
 149     Error = toString(std::move(Err));
 150     return false;
 151   }
 152
 153   // In https://reviews.llvm.org/D154014 we transitioned to using globs instead
 154   // of regexes to match patterns in special case lists. Since this was a
 155   // breaking change, we will temporarily support the original behavior using
 156   // regexes. If "#!special-case-list-v2" is the first line of the file, then
 157   // we will use the new behavior using globs. For more details, see
 158   // https://discourse.llvm.org/t/use-glob-instead-of-regex-for-specialcaselists/71666
 159   bool UseGlobs = MB->getBuffer().startswith("#!special-case-list-v2\n");
 160
 161   for (line_iterator LineIt(*MB, /*SkipBlanks=*/true, /*CommentMarker=*/'#');
 162        !LineIt.is_at_eof(); LineIt++) {
 163     unsigned LineNo = LineIt.line_number();
 164     StringRef Line = LineIt->trim();
 165     if (Line.empty())
 166       continue;
 167
 168     // Save section names
 169     if (Line.startswith("[")) {
 170       if (!Line.endswith("]")) {
 171         Error =
 172             ("malformed section header on line " + Twine(LineNo) + ": " + Line)
 173                 .str();
 174         return false;
 175       }
 176
 177       if (auto Err = addSection(Line.drop_front().drop_back(), LineNo, UseGlobs)
 178                          .moveInto(CurrentSection)) {
 179         Error = toString(std::move(Err));
 180         return false;
 181       }
 182       continue;
 183     }
 184
 185     // Get our prefix and unparsed glob.
 186     auto [Prefix, Postfix] = Line.split(":");
 187     if (Postfix.empty()) {
 188       // Missing ':' in the line.
 189       Error = ("malformed line " + Twine(LineNo) + ": '" + Line + "'").str();
 190       return false;
 191     }
 192
 193     auto [Pattern, Category] = Postfix.split("=");
 194     auto &Entry = CurrentSection->Entries[Prefix][Category];
 195     if (auto Err = Entry.insert(Pattern, LineNo, UseGlobs)) {
 196       Error =
 197           (Twine("malformed ") + (UseGlobs ? "glob" : "regex") + " in line " +
 198            Twine(LineNo) + ": '" + Pattern + "': " + toString(std::move(Err)))
 199               .str();
 200       return false;
 201     }
 202   }
 203   return true;
 204 }
 205
 206 SpecialCaseList::~SpecialCaseList() = default;
 207
 208 bool SpecialCaseList::inSection(StringRef Section, StringRef Prefix,
 209                                 StringRef Query, StringRef Category) const {
 210   return inSectionBlame(Section, Prefix, Query, Category);
 211 }
 212
 213 unsigned SpecialCaseList::inSectionBlame(StringRef Section, StringRef Prefix,
 214                                          StringRef Query,
 215                                          StringRef Category) const {
 216   for (const auto &It : Sections) {
 217     const auto &S = It.getValue();
 218     if (S.SectionMatcher->match(Section)) {
 219       unsigned Blame = inSectionBlame(S.Entries, Prefix, Query, Category);
 220       if (Blame)
 221         return Blame;
 222     }
 223   }
 224   return 0;
 225 }
 226
 227 unsigned SpecialCaseList::inSectionBlame(const SectionEntries &Entries,
 228                                          StringRef Prefix, StringRef Query,
 229                                          StringRef Category) const {
 230   SectionEntries::const_iterator I = Entries.find(Prefix);
 231   if (I == Entries.end()) return 0;
 232   StringMap<Matcher>::const_iterator II = I->second.find(Category);
 233   if (II == I->second.end()) return 0;
 234
 235   return II->getValue().match(Query);
 236 }
 237
 238 } // namespace llvm