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      1 //===-- SpecialCaseList.cpp - special case list for sanitizers ------------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This is a utility class for instrumentation passes (like AddressSanitizer
     11 // or ThreadSanitizer) to avoid instrumenting some functions or global
     12 // variables, or to instrument some functions or global variables in a specific
     13 // way, based on a user-supplied list.
     14 //
     15 //===----------------------------------------------------------------------===//
     16 
     17 #include "llvm/Transforms/Utils/SpecialCaseList.h"
     18 #include "llvm/ADT/OwningPtr.h"
     19 #include "llvm/ADT/SmallVector.h"
     20 #include "llvm/ADT/STLExtras.h"
     21 #include "llvm/ADT/StringExtras.h"
     22 #include "llvm/ADT/StringSet.h"
     23 #include "llvm/IR/DerivedTypes.h"
     24 #include "llvm/IR/Function.h"
     25 #include "llvm/IR/GlobalVariable.h"
     26 #include "llvm/IR/Module.h"
     27 #include "llvm/Support/MemoryBuffer.h"
     28 #include "llvm/Support/Regex.h"
     29 #include "llvm/Support/raw_ostream.h"
     30 #include "llvm/Support/system_error.h"
     31 #include <string>
     32 #include <utility>
     33 
     34 namespace llvm {
     35 
     36 /// Represents a set of regular expressions.  Regular expressions which are
     37 /// "literal" (i.e. no regex metacharacters) are stored in Strings, while all
     38 /// others are represented as a single pipe-separated regex in RegEx.  The
     39 /// reason for doing so is efficiency; StringSet is much faster at matching
     40 /// literal strings than Regex.
     41 struct SpecialCaseList::Entry {
     42   StringSet<> Strings;
     43   Regex *RegEx;
     44 
     45   Entry() : RegEx(0) {}
     46 
     47   bool match(StringRef Query) const {
     48     return Strings.count(Query) || (RegEx && RegEx->match(Query));
     49   }
     50 };
     51 
     52 SpecialCaseList::SpecialCaseList(const StringRef Path) {
     53   // Validate and open blacklist file.
     54   if (Path.empty()) return;
     55   OwningPtr<MemoryBuffer> File;
     56   if (error_code EC = MemoryBuffer::getFile(Path, File)) {
     57     report_fatal_error("Can't open blacklist file: " + Path + ": " +
     58                        EC.message());
     59   }
     60 
     61   init(File.get());
     62 }
     63 
     64 SpecialCaseList::SpecialCaseList(const MemoryBuffer *MB) {
     65   init(MB);
     66 }
     67 
     68 void SpecialCaseList::init(const MemoryBuffer *MB) {
     69   // Iterate through each line in the blacklist file.
     70   SmallVector<StringRef, 16> Lines;
     71   SplitString(MB->getBuffer(), Lines, "\n\r");
     72   StringMap<StringMap<std::string> > Regexps;
     73   for (SmallVectorImpl<StringRef>::iterator I = Lines.begin(), E = Lines.end();
     74        I != E; ++I) {
     75     // Ignore empty lines and lines starting with "#"
     76     if (I->empty() || I->startswith("#"))
     77       continue;
     78     // Get our prefix and unparsed regexp.
     79     std::pair<StringRef, StringRef> SplitLine = I->split(":");
     80     StringRef Prefix = SplitLine.first;
     81     if (SplitLine.second.empty()) {
     82       // Missing ':' in the line.
     83       report_fatal_error("malformed blacklist line: " + SplitLine.first);
     84     }
     85 
     86     std::pair<StringRef, StringRef> SplitRegexp = SplitLine.second.split("=");
     87     std::string Regexp = SplitRegexp.first;
     88     StringRef Category = SplitRegexp.second;
     89 
     90     // Backwards compatibility.
     91     if (Prefix == "global-init") {
     92       Prefix = "global";
     93       Category = "init";
     94     } else if (Prefix == "global-init-type") {
     95       Prefix = "type";
     96       Category = "init";
     97     } else if (Prefix == "global-init-src") {
     98       Prefix = "src";
     99       Category = "init";
    100     }
    101 
    102     // See if we can store Regexp in Strings.
    103     if (Regex::isLiteralERE(Regexp)) {
    104       Entries[Prefix][Category].Strings.insert(Regexp);
    105       continue;
    106     }
    107 
    108     // Replace * with .*
    109     for (size_t pos = 0; (pos = Regexp.find("*", pos)) != std::string::npos;
    110          pos += strlen(".*")) {
    111       Regexp.replace(pos, strlen("*"), ".*");
    112     }
    113 
    114     // Check that the regexp is valid.
    115     Regex CheckRE(Regexp);
    116     std::string Error;
    117     if (!CheckRE.isValid(Error)) {
    118       report_fatal_error("malformed blacklist regex: " + SplitLine.second +
    119           ": " + Error);
    120     }
    121 
    122     // Add this regexp into the proper group by its prefix.
    123     if (!Regexps[Prefix][Category].empty())
    124       Regexps[Prefix][Category] += "|";
    125     Regexps[Prefix][Category] += "^" + Regexp + "$";
    126   }
    127 
    128   // Iterate through each of the prefixes, and create Regexs for them.
    129   for (StringMap<StringMap<std::string> >::const_iterator I = Regexps.begin(),
    130                                                           E = Regexps.end();
    131        I != E; ++I) {
    132     for (StringMap<std::string>::const_iterator II = I->second.begin(),
    133                                                 IE = I->second.end();
    134          II != IE; ++II) {
    135       Entries[I->getKey()][II->getKey()].RegEx = new Regex(II->getValue());
    136     }
    137   }
    138 }
    139 
    140 SpecialCaseList::~SpecialCaseList() {
    141   for (StringMap<StringMap<Entry> >::iterator I = Entries.begin(),
    142                                               E = Entries.end();
    143        I != E; ++I) {
    144     for (StringMap<Entry>::const_iterator II = I->second.begin(),
    145                                           IE = I->second.end();
    146          II != IE; ++II) {
    147       delete II->second.RegEx;
    148     }
    149   }
    150 }
    151 
    152 bool SpecialCaseList::findCategory(const Function &F,
    153                                    StringRef &Category) const {
    154   return findCategory(*F.getParent(), Category) ||
    155          findCategory("fun", F.getName(), Category);
    156 }
    157 
    158 bool SpecialCaseList::isIn(const Function& F, const StringRef Category) const {
    159   return isIn(*F.getParent(), Category) ||
    160          inSectionCategory("fun", F.getName(), Category);
    161 }
    162 
    163 static StringRef GetGVTypeString(const GlobalVariable &G) {
    164   // Types of GlobalVariables are always pointer types.
    165   Type *GType = G.getType()->getElementType();
    166   // For now we support blacklisting struct types only.
    167   if (StructType *SGType = dyn_cast<StructType>(GType)) {
    168     if (!SGType->isLiteral())
    169       return SGType->getName();
    170   }
    171   return "<unknown type>";
    172 }
    173 
    174 bool SpecialCaseList::findCategory(const GlobalVariable &G,
    175                                    StringRef &Category) const {
    176   return findCategory(*G.getParent(), Category) ||
    177          findCategory("global", G.getName(), Category) ||
    178          findCategory("type", GetGVTypeString(G), Category);
    179 }
    180 
    181 bool SpecialCaseList::isIn(const GlobalVariable &G,
    182                            const StringRef Category) const {
    183   return isIn(*G.getParent(), Category) ||
    184          inSectionCategory("global", G.getName(), Category) ||
    185          inSectionCategory("type", GetGVTypeString(G), Category);
    186 }
    187 
    188 bool SpecialCaseList::findCategory(const Module &M, StringRef &Category) const {
    189   return findCategory("src", M.getModuleIdentifier(), Category);
    190 }
    191 
    192 bool SpecialCaseList::isIn(const Module &M, const StringRef Category) const {
    193   return inSectionCategory("src", M.getModuleIdentifier(), Category);
    194 }
    195 
    196 bool SpecialCaseList::findCategory(const StringRef Section,
    197                                    const StringRef Query,
    198                                    StringRef &Category) const {
    199   StringMap<StringMap<Entry> >::const_iterator I = Entries.find(Section);
    200   if (I == Entries.end()) return false;
    201 
    202   for (StringMap<Entry>::const_iterator II = I->second.begin(),
    203                                         IE = I->second.end();
    204        II != IE; ++II) {
    205     if (II->getValue().match(Query)) {
    206       Category = II->first();
    207       return true;
    208     }
    209   }
    210 
    211   return false;
    212 }
    213 
    214 bool SpecialCaseList::inSectionCategory(const StringRef Section,
    215                                         const StringRef Query,
    216                                         const StringRef Category) const {
    217   StringMap<StringMap<Entry> >::const_iterator I = Entries.find(Section);
    218   if (I == Entries.end()) return false;
    219   StringMap<Entry>::const_iterator II = I->second.find(Category);
    220   if (II == I->second.end()) return false;
    221 
    222   return II->getValue().match(Query);
    223 }
    224 
    225 }  // namespace llvm
    226