xref: /freebsd/contrib/llvm-project/clang/lib/Tooling/JSONCompilationDatabase.cpp (revision f976241773df2260e6170317080761d1c5814fe5)
1 //===- JSONCompilationDatabase.cpp ----------------------------------------===//
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 file contains the implementation of the JSONCompilationDatabase.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "clang/Tooling/JSONCompilationDatabase.h"
14 #include "clang/Basic/LLVM.h"
15 #include "clang/Tooling/CompilationDatabase.h"
16 #include "clang/Tooling/CompilationDatabasePluginRegistry.h"
17 #include "clang/Tooling/Tooling.h"
18 #include "llvm/ADT/Optional.h"
19 #include "llvm/ADT/STLExtras.h"
20 #include "llvm/ADT/SmallString.h"
21 #include "llvm/ADT/SmallVector.h"
22 #include "llvm/ADT/StringRef.h"
23 #include "llvm/ADT/Triple.h"
24 #include "llvm/Support/Allocator.h"
25 #include "llvm/Support/Casting.h"
26 #include "llvm/Support/CommandLine.h"
27 #include "llvm/Support/ErrorOr.h"
28 #include "llvm/Support/Host.h"
29 #include "llvm/Support/MemoryBuffer.h"
30 #include "llvm/Support/Path.h"
31 #include "llvm/Support/StringSaver.h"
32 #include "llvm/Support/YAMLParser.h"
33 #include "llvm/Support/raw_ostream.h"
34 #include <cassert>
35 #include <memory>
36 #include <string>
37 #include <system_error>
38 #include <tuple>
39 #include <utility>
40 #include <vector>
41 
42 using namespace clang;
43 using namespace tooling;
44 
45 namespace {
46 
47 /// A parser for escaped strings of command line arguments.
48 ///
49 /// Assumes \-escaping for quoted arguments (see the documentation of
50 /// unescapeCommandLine(...)).
51 class CommandLineArgumentParser {
52  public:
53   CommandLineArgumentParser(StringRef CommandLine)
54       : Input(CommandLine), Position(Input.begin()-1) {}
55 
56   std::vector<std::string> parse() {
57     bool HasMoreInput = true;
58     while (HasMoreInput && nextNonWhitespace()) {
59       std::string Argument;
60       HasMoreInput = parseStringInto(Argument);
61       CommandLine.push_back(Argument);
62     }
63     return CommandLine;
64   }
65 
66  private:
67   // All private methods return true if there is more input available.
68 
69   bool parseStringInto(std::string &String) {
70     do {
71       if (*Position == '"') {
72         if (!parseDoubleQuotedStringInto(String)) return false;
73       } else if (*Position == '\'') {
74         if (!parseSingleQuotedStringInto(String)) return false;
75       } else {
76         if (!parseFreeStringInto(String)) return false;
77       }
78     } while (*Position != ' ');
79     return true;
80   }
81 
82   bool parseDoubleQuotedStringInto(std::string &String) {
83     if (!next()) return false;
84     while (*Position != '"') {
85       if (!skipEscapeCharacter()) return false;
86       String.push_back(*Position);
87       if (!next()) return false;
88     }
89     return next();
90   }
91 
92   bool parseSingleQuotedStringInto(std::string &String) {
93     if (!next()) return false;
94     while (*Position != '\'') {
95       String.push_back(*Position);
96       if (!next()) return false;
97     }
98     return next();
99   }
100 
101   bool parseFreeStringInto(std::string &String) {
102     do {
103       if (!skipEscapeCharacter()) return false;
104       String.push_back(*Position);
105       if (!next()) return false;
106     } while (*Position != ' ' && *Position != '"' && *Position != '\'');
107     return true;
108   }
109 
110   bool skipEscapeCharacter() {
111     if (*Position == '\\') {
112       return next();
113     }
114     return true;
115   }
116 
117   bool nextNonWhitespace() {
118     do {
119       if (!next()) return false;
120     } while (*Position == ' ');
121     return true;
122   }
123 
124   bool next() {
125     ++Position;
126     return Position != Input.end();
127   }
128 
129   const StringRef Input;
130   StringRef::iterator Position;
131   std::vector<std::string> CommandLine;
132 };
133 
134 std::vector<std::string> unescapeCommandLine(JSONCommandLineSyntax Syntax,
135                                              StringRef EscapedCommandLine) {
136   if (Syntax == JSONCommandLineSyntax::AutoDetect) {
137     Syntax = JSONCommandLineSyntax::Gnu;
138     llvm::Triple Triple(llvm::sys::getProcessTriple());
139     if (Triple.getOS() == llvm::Triple::OSType::Win32) {
140       // Assume Windows command line parsing on Win32 unless the triple
141       // explicitly tells us otherwise.
142       if (!Triple.hasEnvironment() ||
143           Triple.getEnvironment() == llvm::Triple::EnvironmentType::MSVC)
144         Syntax = JSONCommandLineSyntax::Windows;
145     }
146   }
147 
148   if (Syntax == JSONCommandLineSyntax::Windows) {
149     llvm::BumpPtrAllocator Alloc;
150     llvm::StringSaver Saver(Alloc);
151     llvm::SmallVector<const char *, 64> T;
152     llvm::cl::TokenizeWindowsCommandLine(EscapedCommandLine, Saver, T);
153     std::vector<std::string> Result(T.begin(), T.end());
154     return Result;
155   }
156   assert(Syntax == JSONCommandLineSyntax::Gnu);
157   CommandLineArgumentParser parser(EscapedCommandLine);
158   return parser.parse();
159 }
160 
161 // This plugin locates a nearby compile_command.json file, and also infers
162 // compile commands for files not present in the database.
163 class JSONCompilationDatabasePlugin : public CompilationDatabasePlugin {
164   std::unique_ptr<CompilationDatabase>
165   loadFromDirectory(StringRef Directory, std::string &ErrorMessage) override {
166     SmallString<1024> JSONDatabasePath(Directory);
167     llvm::sys::path::append(JSONDatabasePath, "compile_commands.json");
168     auto Base = JSONCompilationDatabase::loadFromFile(
169         JSONDatabasePath, ErrorMessage, JSONCommandLineSyntax::AutoDetect);
170     return Base ? inferTargetAndDriverMode(
171                       inferMissingCompileCommands(std::move(Base)))
172                 : nullptr;
173   }
174 };
175 
176 } // namespace
177 
178 // Register the JSONCompilationDatabasePlugin with the
179 // CompilationDatabasePluginRegistry using this statically initialized variable.
180 static CompilationDatabasePluginRegistry::Add<JSONCompilationDatabasePlugin>
181 X("json-compilation-database", "Reads JSON formatted compilation databases");
182 
183 namespace clang {
184 namespace tooling {
185 
186 // This anchor is used to force the linker to link in the generated object file
187 // and thus register the JSONCompilationDatabasePlugin.
188 volatile int JSONAnchorSource = 0;
189 
190 } // namespace tooling
191 } // namespace clang
192 
193 std::unique_ptr<JSONCompilationDatabase>
194 JSONCompilationDatabase::loadFromFile(StringRef FilePath,
195                                       std::string &ErrorMessage,
196                                       JSONCommandLineSyntax Syntax) {
197   // Don't mmap: if we're a long-lived process, the build system may overwrite.
198   llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> DatabaseBuffer =
199       llvm::MemoryBuffer::getFile(FilePath, /*FileSize=*/-1,
200                                   /*RequiresNullTerminator=*/true,
201                                   /*IsVolatile=*/true);
202   if (std::error_code Result = DatabaseBuffer.getError()) {
203     ErrorMessage = "Error while opening JSON database: " + Result.message();
204     return nullptr;
205   }
206   std::unique_ptr<JSONCompilationDatabase> Database(
207       new JSONCompilationDatabase(std::move(*DatabaseBuffer), Syntax));
208   if (!Database->parse(ErrorMessage))
209     return nullptr;
210   return Database;
211 }
212 
213 std::unique_ptr<JSONCompilationDatabase>
214 JSONCompilationDatabase::loadFromBuffer(StringRef DatabaseString,
215                                         std::string &ErrorMessage,
216                                         JSONCommandLineSyntax Syntax) {
217   std::unique_ptr<llvm::MemoryBuffer> DatabaseBuffer(
218       llvm::MemoryBuffer::getMemBuffer(DatabaseString));
219   std::unique_ptr<JSONCompilationDatabase> Database(
220       new JSONCompilationDatabase(std::move(DatabaseBuffer), Syntax));
221   if (!Database->parse(ErrorMessage))
222     return nullptr;
223   return Database;
224 }
225 
226 std::vector<CompileCommand>
227 JSONCompilationDatabase::getCompileCommands(StringRef FilePath) const {
228   SmallString<128> NativeFilePath;
229   llvm::sys::path::native(FilePath, NativeFilePath);
230 
231   std::string Error;
232   llvm::raw_string_ostream ES(Error);
233   StringRef Match = MatchTrie.findEquivalent(NativeFilePath, ES);
234   if (Match.empty())
235     return {};
236   const auto CommandsRefI = IndexByFile.find(Match);
237   if (CommandsRefI == IndexByFile.end())
238     return {};
239   std::vector<CompileCommand> Commands;
240   getCommands(CommandsRefI->getValue(), Commands);
241   return Commands;
242 }
243 
244 std::vector<std::string>
245 JSONCompilationDatabase::getAllFiles() const {
246   std::vector<std::string> Result;
247   for (const auto &CommandRef : IndexByFile)
248     Result.push_back(CommandRef.first().str());
249   return Result;
250 }
251 
252 std::vector<CompileCommand>
253 JSONCompilationDatabase::getAllCompileCommands() const {
254   std::vector<CompileCommand> Commands;
255   getCommands(AllCommands, Commands);
256   return Commands;
257 }
258 
259 static llvm::StringRef stripExecutableExtension(llvm::StringRef Name) {
260   Name.consume_back(".exe");
261   return Name;
262 }
263 
264 // There are compiler-wrappers (ccache, distcc, gomacc) that take the "real"
265 // compiler as an argument, e.g. distcc gcc -O3 foo.c.
266 // These end up in compile_commands.json when people set CC="distcc gcc".
267 // Clang's driver doesn't understand this, so we need to unwrap.
268 static bool unwrapCommand(std::vector<std::string> &Args) {
269   if (Args.size() < 2)
270     return false;
271   StringRef Wrapper =
272       stripExecutableExtension(llvm::sys::path::filename(Args.front()));
273   if (Wrapper == "distcc" || Wrapper == "gomacc" || Wrapper == "ccache") {
274     // Most of these wrappers support being invoked 3 ways:
275     // `distcc g++ file.c` This is the mode we're trying to match.
276     //                     We need to drop `distcc`.
277     // `distcc file.c`     This acts like compiler is cc or similar.
278     //                     Clang's driver can handle this, no change needed.
279     // `g++ file.c`        g++ is a symlink to distcc.
280     //                     We don't even notice this case, and all is well.
281     //
282     // We need to distinguish between the first and second case.
283     // The wrappers themselves don't take flags, so Args[1] is a compiler flag,
284     // an input file, or a compiler. Inputs have extensions, compilers don't.
285     bool HasCompiler =
286         (Args[1][0] != '-') &&
287         !llvm::sys::path::has_extension(stripExecutableExtension(Args[1]));
288     if (HasCompiler) {
289       Args.erase(Args.begin());
290       return true;
291     }
292     // If !HasCompiler, wrappers act like GCC. Fine: so do we.
293   }
294   return false;
295 }
296 
297 static std::vector<std::string>
298 nodeToCommandLine(JSONCommandLineSyntax Syntax,
299                   const std::vector<llvm::yaml::ScalarNode *> &Nodes) {
300   SmallString<1024> Storage;
301   std::vector<std::string> Arguments;
302   if (Nodes.size() == 1)
303     Arguments = unescapeCommandLine(Syntax, Nodes[0]->getValue(Storage));
304   else
305     for (const auto *Node : Nodes)
306       Arguments.push_back(Node->getValue(Storage));
307   // There may be multiple wrappers: using distcc and ccache together is common.
308   while (unwrapCommand(Arguments))
309     ;
310   return Arguments;
311 }
312 
313 void JSONCompilationDatabase::getCommands(
314     ArrayRef<CompileCommandRef> CommandsRef,
315     std::vector<CompileCommand> &Commands) const {
316   for (const auto &CommandRef : CommandsRef) {
317     SmallString<8> DirectoryStorage;
318     SmallString<32> FilenameStorage;
319     SmallString<32> OutputStorage;
320     auto Output = std::get<3>(CommandRef);
321     Commands.emplace_back(
322         std::get<0>(CommandRef)->getValue(DirectoryStorage),
323         std::get<1>(CommandRef)->getValue(FilenameStorage),
324         nodeToCommandLine(Syntax, std::get<2>(CommandRef)),
325         Output ? Output->getValue(OutputStorage) : "");
326   }
327 }
328 
329 bool JSONCompilationDatabase::parse(std::string &ErrorMessage) {
330   llvm::yaml::document_iterator I = YAMLStream.begin();
331   if (I == YAMLStream.end()) {
332     ErrorMessage = "Error while parsing YAML.";
333     return false;
334   }
335   llvm::yaml::Node *Root = I->getRoot();
336   if (!Root) {
337     ErrorMessage = "Error while parsing YAML.";
338     return false;
339   }
340   auto *Array = dyn_cast<llvm::yaml::SequenceNode>(Root);
341   if (!Array) {
342     ErrorMessage = "Expected array.";
343     return false;
344   }
345   for (auto &NextObject : *Array) {
346     auto *Object = dyn_cast<llvm::yaml::MappingNode>(&NextObject);
347     if (!Object) {
348       ErrorMessage = "Expected object.";
349       return false;
350     }
351     llvm::yaml::ScalarNode *Directory = nullptr;
352     llvm::Optional<std::vector<llvm::yaml::ScalarNode *>> Command;
353     llvm::yaml::ScalarNode *File = nullptr;
354     llvm::yaml::ScalarNode *Output = nullptr;
355     for (auto& NextKeyValue : *Object) {
356       auto *KeyString = dyn_cast<llvm::yaml::ScalarNode>(NextKeyValue.getKey());
357       if (!KeyString) {
358         ErrorMessage = "Expected strings as key.";
359         return false;
360       }
361       SmallString<10> KeyStorage;
362       StringRef KeyValue = KeyString->getValue(KeyStorage);
363       llvm::yaml::Node *Value = NextKeyValue.getValue();
364       if (!Value) {
365         ErrorMessage = "Expected value.";
366         return false;
367       }
368       auto *ValueString = dyn_cast<llvm::yaml::ScalarNode>(Value);
369       auto *SequenceString = dyn_cast<llvm::yaml::SequenceNode>(Value);
370       if (KeyValue == "arguments" && !SequenceString) {
371         ErrorMessage = "Expected sequence as value.";
372         return false;
373       } else if (KeyValue != "arguments" && !ValueString) {
374         ErrorMessage = "Expected string as value.";
375         return false;
376       }
377       if (KeyValue == "directory") {
378         Directory = ValueString;
379       } else if (KeyValue == "arguments") {
380         Command = std::vector<llvm::yaml::ScalarNode *>();
381         for (auto &Argument : *SequenceString) {
382           auto *Scalar = dyn_cast<llvm::yaml::ScalarNode>(&Argument);
383           if (!Scalar) {
384             ErrorMessage = "Only strings are allowed in 'arguments'.";
385             return false;
386           }
387           Command->push_back(Scalar);
388         }
389       } else if (KeyValue == "command") {
390         if (!Command)
391           Command = std::vector<llvm::yaml::ScalarNode *>(1, ValueString);
392       } else if (KeyValue == "file") {
393         File = ValueString;
394       } else if (KeyValue == "output") {
395         Output = ValueString;
396       } else {
397         ErrorMessage = ("Unknown key: \"" +
398                         KeyString->getRawValue() + "\"").str();
399         return false;
400       }
401     }
402     if (!File) {
403       ErrorMessage = "Missing key: \"file\".";
404       return false;
405     }
406     if (!Command) {
407       ErrorMessage = "Missing key: \"command\" or \"arguments\".";
408       return false;
409     }
410     if (!Directory) {
411       ErrorMessage = "Missing key: \"directory\".";
412       return false;
413     }
414     SmallString<8> FileStorage;
415     StringRef FileName = File->getValue(FileStorage);
416     SmallString<128> NativeFilePath;
417     if (llvm::sys::path::is_relative(FileName)) {
418       SmallString<8> DirectoryStorage;
419       SmallString<128> AbsolutePath(
420           Directory->getValue(DirectoryStorage));
421       llvm::sys::path::append(AbsolutePath, FileName);
422       llvm::sys::path::remove_dots(AbsolutePath, /*remove_dot_dot=*/ true);
423       llvm::sys::path::native(AbsolutePath, NativeFilePath);
424     } else {
425       llvm::sys::path::native(FileName, NativeFilePath);
426     }
427     auto Cmd = CompileCommandRef(Directory, File, *Command, Output);
428     IndexByFile[NativeFilePath].push_back(Cmd);
429     AllCommands.push_back(Cmd);
430     MatchTrie.insert(NativeFilePath);
431   }
432   return true;
433 }
434