xref: /freebsd/contrib/llvm-project/llvm/lib/Support/SpecialCaseList.cpp (revision a7dea1671b87c07d2d266f836bfa8b58efc7c134)
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 <string>
22 #include <system_error>
23 #include <utility>
24 
25 #include <stdio.h>
26 namespace llvm {
27 
28 bool SpecialCaseList::Matcher::insert(std::string Regexp,
29                                       unsigned LineNumber,
30                                       std::string &REError) {
31   if (Regexp.empty()) {
32     REError = "Supplied regexp was blank";
33     return false;
34   }
35 
36   if (Regex::isLiteralERE(Regexp)) {
37     Strings[Regexp] = LineNumber;
38     return true;
39   }
40   Trigrams.insert(Regexp);
41 
42   // Replace * with .*
43   for (size_t pos = 0; (pos = Regexp.find('*', pos)) != std::string::npos;
44        pos += strlen(".*")) {
45     Regexp.replace(pos, strlen("*"), ".*");
46   }
47 
48   Regexp = (Twine("^(") + StringRef(Regexp) + ")$").str();
49 
50   // Check that the regexp is valid.
51   Regex CheckRE(Regexp);
52   if (!CheckRE.isValid(REError))
53     return false;
54 
55   RegExes.emplace_back(
56       std::make_pair(std::make_unique<Regex>(std::move(CheckRE)), LineNumber));
57   return true;
58 }
59 
60 unsigned SpecialCaseList::Matcher::match(StringRef Query) const {
61   auto It = Strings.find(Query);
62   if (It != Strings.end())
63     return It->second;
64   if (Trigrams.isDefinitelyOut(Query))
65     return false;
66   for (auto& RegExKV : RegExes)
67     if (RegExKV.first->match(Query))
68       return RegExKV.second;
69   return 0;
70 }
71 
72 std::unique_ptr<SpecialCaseList>
73 SpecialCaseList::create(const std::vector<std::string> &Paths,
74                         std::string &Error) {
75   std::unique_ptr<SpecialCaseList> SCL(new SpecialCaseList());
76   if (SCL->createInternal(Paths, Error))
77     return SCL;
78   return nullptr;
79 }
80 
81 std::unique_ptr<SpecialCaseList> SpecialCaseList::create(const MemoryBuffer *MB,
82                                                          std::string &Error) {
83   std::unique_ptr<SpecialCaseList> SCL(new SpecialCaseList());
84   if (SCL->createInternal(MB, Error))
85     return SCL;
86   return nullptr;
87 }
88 
89 std::unique_ptr<SpecialCaseList>
90 SpecialCaseList::createOrDie(const std::vector<std::string> &Paths) {
91   std::string Error;
92   if (auto SCL = create(Paths, Error))
93     return SCL;
94   report_fatal_error(Error);
95 }
96 
97 bool SpecialCaseList::createInternal(const std::vector<std::string> &Paths,
98                                      std::string &Error) {
99   StringMap<size_t> Sections;
100   for (const auto &Path : Paths) {
101     ErrorOr<std::unique_ptr<MemoryBuffer>> FileOrErr =
102         MemoryBuffer::getFile(Path);
103     if (std::error_code EC = FileOrErr.getError()) {
104       Error = (Twine("can't open file '") + Path + "': " + EC.message()).str();
105       return false;
106     }
107     std::string ParseError;
108     if (!parse(FileOrErr.get().get(), Sections, ParseError)) {
109       Error = (Twine("error parsing file '") + Path + "': " + ParseError).str();
110       return false;
111     }
112   }
113   return true;
114 }
115 
116 bool SpecialCaseList::createInternal(const MemoryBuffer *MB,
117                                      std::string &Error) {
118   StringMap<size_t> Sections;
119   if (!parse(MB, Sections, Error))
120     return false;
121   return true;
122 }
123 
124 bool SpecialCaseList::parse(const MemoryBuffer *MB,
125                             StringMap<size_t> &SectionsMap,
126                             std::string &Error) {
127   // Iterate through each line in the blacklist file.
128   SmallVector<StringRef, 16> Lines;
129   MB->getBuffer().split(Lines, '\n');
130 
131   unsigned LineNo = 1;
132   StringRef Section = "*";
133 
134   for (auto I = Lines.begin(), E = Lines.end(); I != E; ++I, ++LineNo) {
135     *I = I->trim();
136     // Ignore empty lines and lines starting with "#"
137     if (I->empty() || I->startswith("#"))
138       continue;
139 
140     // Save section names
141     if (I->startswith("[")) {
142       if (!I->endswith("]")) {
143         Error = (Twine("malformed section header on line ") + Twine(LineNo) +
144                  ": " + *I).str();
145         return false;
146       }
147 
148       Section = I->slice(1, I->size() - 1);
149 
150       std::string REError;
151       Regex CheckRE(Section);
152       if (!CheckRE.isValid(REError)) {
153         Error =
154             (Twine("malformed regex for section ") + Section + ": '" + REError)
155                 .str();
156         return false;
157       }
158 
159       continue;
160     }
161 
162     // Get our prefix and unparsed regexp.
163     std::pair<StringRef, StringRef> SplitLine = I->split(":");
164     StringRef Prefix = SplitLine.first;
165     if (SplitLine.second.empty()) {
166       // Missing ':' in the line.
167       Error = (Twine("malformed line ") + Twine(LineNo) + ": '" +
168                SplitLine.first + "'").str();
169       return false;
170     }
171 
172     std::pair<StringRef, StringRef> SplitRegexp = SplitLine.second.split("=");
173     std::string Regexp = SplitRegexp.first;
174     StringRef Category = SplitRegexp.second;
175 
176     // Create this section if it has not been seen before.
177     if (SectionsMap.find(Section) == SectionsMap.end()) {
178       std::unique_ptr<Matcher> M = std::make_unique<Matcher>();
179       std::string REError;
180       if (!M->insert(Section, LineNo, REError)) {
181         Error = (Twine("malformed section ") + Section + ": '" + REError).str();
182         return false;
183       }
184 
185       SectionsMap[Section] = Sections.size();
186       Sections.emplace_back(std::move(M));
187     }
188 
189     auto &Entry = Sections[SectionsMap[Section]].Entries[Prefix][Category];
190     std::string REError;
191     if (!Entry.insert(std::move(Regexp), LineNo, REError)) {
192       Error = (Twine("malformed regex in line ") + Twine(LineNo) + ": '" +
193                SplitLine.second + "': " + REError).str();
194       return false;
195     }
196   }
197   return true;
198 }
199 
200 SpecialCaseList::~SpecialCaseList() {}
201 
202 bool SpecialCaseList::inSection(StringRef Section, StringRef Prefix,
203                                 StringRef Query, StringRef Category) const {
204   return inSectionBlame(Section, Prefix, Query, Category);
205 }
206 
207 unsigned SpecialCaseList::inSectionBlame(StringRef Section, StringRef Prefix,
208                                          StringRef Query,
209                                          StringRef Category) const {
210   for (auto &SectionIter : Sections)
211     if (SectionIter.SectionMatcher->match(Section)) {
212       unsigned Blame =
213           inSectionBlame(SectionIter.Entries, Prefix, Query, Category);
214       if (Blame)
215         return Blame;
216     }
217   return 0;
218 }
219 
220 unsigned SpecialCaseList::inSectionBlame(const SectionEntries &Entries,
221                                          StringRef Prefix, StringRef Query,
222                                          StringRef Category) const {
223   SectionEntries::const_iterator I = Entries.find(Prefix);
224   if (I == Entries.end()) return 0;
225   StringMap<Matcher>::const_iterator II = I->second.find(Category);
226   if (II == I->second.end()) return 0;
227 
228   return II->getValue().match(Query);
229 }
230 
231 }  // namespace llvm
232