1 //===--- ConfigCompile.cpp - Translating Fragments into Config ------------===//
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 // Fragments are applied to Configs in two steps:
10 //
11 // 1. (When the fragment is first loaded)
12 //    FragmentCompiler::compile() traverses the Fragment and creates
13 //    function objects that know how to apply the configuration.
14 // 2. (Every time a config is required)
15 //    CompiledFragment() executes these functions to populate the Config.
16 //
17 // Work could be split between these steps in different ways. We try to
18 // do as much work as possible in the first step. For example, regexes are
19 // compiled in stage 1 and captured by the apply function. This is because:
20 //
21 //  - it's more efficient, as the work done in stage 1 must only be done once
22 //  - problems can be reported in stage 1, in stage 2 we must silently recover
23 //
24 //===----------------------------------------------------------------------===//
25 
26 #include "CompileCommands.h"
27 #include "Config.h"
28 #include "ConfigFragment.h"
29 #include "ConfigProvider.h"
30 #include "Diagnostics.h"
31 #include "Features.inc"
32 #include "TidyProvider.h"
33 #include "support/Logger.h"
34 #include "support/Path.h"
35 #include "support/Trace.h"
36 #include "llvm/ADT/None.h"
37 #include "llvm/ADT/Optional.h"
38 #include "llvm/ADT/STLExtras.h"
39 #include "llvm/ADT/SmallString.h"
40 #include "llvm/ADT/StringRef.h"
41 #include "llvm/ADT/StringSwitch.h"
42 #include "llvm/Support/Error.h"
43 #include "llvm/Support/FileSystem.h"
44 #include "llvm/Support/Format.h"
45 #include "llvm/Support/FormatVariadic.h"
46 #include "llvm/Support/Path.h"
47 #include "llvm/Support/Regex.h"
48 #include "llvm/Support/SMLoc.h"
49 #include "llvm/Support/SourceMgr.h"
50 #include <string>
51 
52 namespace clang {
53 namespace clangd {
54 namespace config {
55 namespace {
56 
57 // Returns an empty stringref if Path is not under FragmentDir. Returns Path
58 // as-is when FragmentDir is empty.
59 llvm::StringRef configRelative(llvm::StringRef Path,
60                                llvm::StringRef FragmentDir) {
61   if (FragmentDir.empty())
62     return Path;
63   if (!Path.consume_front(FragmentDir))
64     return llvm::StringRef();
65   return Path.empty() ? "." : Path;
66 }
67 
68 struct CompiledFragmentImpl {
69   // The independent conditions to check before using settings from this config.
70   // The following fragment has *two* conditions:
71   //   If: { Platform: [mac, linux], PathMatch: foo/.* }
72   // All of them must be satisfied: the platform and path conditions are ANDed.
73   // The OR logic for the platform condition is implemented inside the function.
74   std::vector<llvm::unique_function<bool(const Params &) const>> Conditions;
75   // Mutations that this fragment will apply to the configuration.
76   // These are invoked only if the conditions are satisfied.
77   std::vector<llvm::unique_function<void(const Params &, Config &) const>>
78       Apply;
79 
80   bool operator()(const Params &P, Config &C) const {
81     for (const auto &C : Conditions) {
82       if (!C(P)) {
83         dlog("Config fragment {0}: condition not met", this);
84         return false;
85       }
86     }
87     dlog("Config fragment {0}: applying {1} rules", this, Apply.size());
88     for (const auto &A : Apply)
89       A(P, C);
90     return true;
91   }
92 };
93 
94 // Wrapper around condition compile() functions to reduce arg-passing.
95 struct FragmentCompiler {
96   FragmentCompiler(CompiledFragmentImpl &Out, DiagnosticCallback D,
97                    llvm::SourceMgr *SM)
98       : Out(Out), Diagnostic(D), SourceMgr(SM) {}
99   CompiledFragmentImpl &Out;
100   DiagnosticCallback Diagnostic;
101   llvm::SourceMgr *SourceMgr;
102   // Normalized Fragment::SourceInfo::Directory.
103   std::string FragmentDirectory;
104   bool Trusted = false;
105 
106   llvm::Optional<llvm::Regex>
107   compileRegex(const Located<std::string> &Text,
108                llvm::Regex::RegexFlags Flags = llvm::Regex::NoFlags) {
109     std::string Anchored = "^(" + *Text + ")$";
110     llvm::Regex Result(Anchored, Flags);
111     std::string RegexError;
112     if (!Result.isValid(RegexError)) {
113       diag(Error, "Invalid regex " + Anchored + ": " + RegexError, Text.Range);
114       return llvm::None;
115     }
116     return Result;
117   }
118 
119   llvm::Optional<std::string> makeAbsolute(Located<std::string> Path,
120                                            llvm::StringLiteral Description,
121                                            llvm::sys::path::Style Style) {
122     if (llvm::sys::path::is_absolute(*Path))
123       return *Path;
124     if (FragmentDirectory.empty()) {
125       diag(Error,
126            llvm::formatv(
127                "{0} must be an absolute path, because this fragment is not "
128                "associated with any directory.",
129                Description)
130                .str(),
131            Path.Range);
132       return llvm::None;
133     }
134     llvm::SmallString<256> AbsPath = llvm::StringRef(*Path);
135     llvm::sys::fs::make_absolute(FragmentDirectory, AbsPath);
136     llvm::sys::path::native(AbsPath, Style);
137     return AbsPath.str().str();
138   }
139 
140   // Helper with similar API to StringSwitch, for parsing enum values.
141   template <typename T> class EnumSwitch {
142     FragmentCompiler &Outer;
143     llvm::StringRef EnumName;
144     const Located<std::string> &Input;
145     llvm::Optional<T> Result;
146     llvm::SmallVector<llvm::StringLiteral> ValidValues;
147 
148   public:
149     EnumSwitch(llvm::StringRef EnumName, const Located<std::string> &In,
150                FragmentCompiler &Outer)
151         : Outer(Outer), EnumName(EnumName), Input(In) {}
152 
153     EnumSwitch &map(llvm::StringLiteral Name, T Value) {
154       assert(!llvm::is_contained(ValidValues, Name) && "Duplicate value!");
155       ValidValues.push_back(Name);
156       if (!Result && *Input == Name)
157         Result = Value;
158       return *this;
159     }
160 
161     llvm::Optional<T> value() {
162       if (!Result)
163         Outer.diag(
164             Warning,
165             llvm::formatv("Invalid {0} value '{1}'. Valid values are {2}.",
166                           EnumName, *Input, llvm::join(ValidValues, ", "))
167                 .str(),
168             Input.Range);
169       return Result;
170     };
171   };
172 
173   // Attempt to parse a specified string into an enum.
174   // Yields llvm::None and produces a diagnostic on failure.
175   //
176   // Optional<T> Value = compileEnum<En>("Foo", Frag.Foo)
177   //    .map("Foo", Enum::Foo)
178   //    .map("Bar", Enum::Bar)
179   //    .value();
180   template <typename T>
181   EnumSwitch<T> compileEnum(llvm::StringRef EnumName,
182                             const Located<std::string> &In) {
183     return EnumSwitch<T>(EnumName, In, *this);
184   }
185 
186   void compile(Fragment &&F) {
187     Trusted = F.Source.Trusted;
188     if (!F.Source.Directory.empty()) {
189       FragmentDirectory = llvm::sys::path::convert_to_slash(F.Source.Directory);
190       if (FragmentDirectory.back() != '/')
191         FragmentDirectory += '/';
192     }
193     compile(std::move(F.If));
194     compile(std::move(F.CompileFlags));
195     compile(std::move(F.Index));
196     compile(std::move(F.Diagnostics));
197     compile(std::move(F.Completion));
198   }
199 
200   void compile(Fragment::IfBlock &&F) {
201     if (F.HasUnrecognizedCondition)
202       Out.Conditions.push_back([&](const Params &) { return false; });
203 
204 #ifdef CLANGD_PATH_CASE_INSENSITIVE
205     llvm::Regex::RegexFlags Flags = llvm::Regex::IgnoreCase;
206 #else
207     llvm::Regex::RegexFlags Flags = llvm::Regex::NoFlags;
208 #endif
209 
210     auto PathMatch = std::make_unique<std::vector<llvm::Regex>>();
211     for (auto &Entry : F.PathMatch) {
212       if (auto RE = compileRegex(Entry, Flags))
213         PathMatch->push_back(std::move(*RE));
214     }
215     if (!PathMatch->empty()) {
216       Out.Conditions.push_back(
217           [PathMatch(std::move(PathMatch)),
218            FragmentDir(FragmentDirectory)](const Params &P) {
219             if (P.Path.empty())
220               return false;
221             llvm::StringRef Path = configRelative(P.Path, FragmentDir);
222             // Ignore the file if it is not nested under Fragment.
223             if (Path.empty())
224               return false;
225             return llvm::any_of(*PathMatch, [&](const llvm::Regex &RE) {
226               return RE.match(Path);
227             });
228           });
229     }
230 
231     auto PathExclude = std::make_unique<std::vector<llvm::Regex>>();
232     for (auto &Entry : F.PathExclude) {
233       if (auto RE = compileRegex(Entry, Flags))
234         PathExclude->push_back(std::move(*RE));
235     }
236     if (!PathExclude->empty()) {
237       Out.Conditions.push_back(
238           [PathExclude(std::move(PathExclude)),
239            FragmentDir(FragmentDirectory)](const Params &P) {
240             if (P.Path.empty())
241               return false;
242             llvm::StringRef Path = configRelative(P.Path, FragmentDir);
243             // Ignore the file if it is not nested under Fragment.
244             if (Path.empty())
245               return true;
246             return llvm::none_of(*PathExclude, [&](const llvm::Regex &RE) {
247               return RE.match(Path);
248             });
249           });
250     }
251   }
252 
253   void compile(Fragment::CompileFlagsBlock &&F) {
254     if (!F.Remove.empty()) {
255       auto Remove = std::make_shared<ArgStripper>();
256       for (auto &A : F.Remove)
257         Remove->strip(*A);
258       Out.Apply.push_back([Remove(std::shared_ptr<const ArgStripper>(
259                               std::move(Remove)))](const Params &, Config &C) {
260         C.CompileFlags.Edits.push_back(
261             [Remove](std::vector<std::string> &Args) {
262               Remove->process(Args);
263             });
264       });
265     }
266 
267     if (!F.Add.empty()) {
268       std::vector<std::string> Add;
269       for (auto &A : F.Add)
270         Add.push_back(std::move(*A));
271       Out.Apply.push_back([Add(std::move(Add))](const Params &, Config &C) {
272         C.CompileFlags.Edits.push_back([Add](std::vector<std::string> &Args) {
273           Args.insert(Args.end(), Add.begin(), Add.end());
274         });
275       });
276     }
277 
278     if (F.CompilationDatabase) {
279       llvm::Optional<Config::CDBSearchSpec> Spec;
280       if (**F.CompilationDatabase == "Ancestors") {
281         Spec.emplace();
282         Spec->Policy = Config::CDBSearchSpec::Ancestors;
283       } else if (**F.CompilationDatabase == "None") {
284         Spec.emplace();
285         Spec->Policy = Config::CDBSearchSpec::NoCDBSearch;
286       } else {
287         if (auto Path =
288                 makeAbsolute(*F.CompilationDatabase, "CompilationDatabase",
289                              llvm::sys::path::Style::native)) {
290           // Drop trailing slash to put the path in canonical form.
291           // Should makeAbsolute do this?
292           llvm::StringRef Rel = llvm::sys::path::relative_path(*Path);
293           if (!Rel.empty() && llvm::sys::path::is_separator(Rel.back()))
294             Path->pop_back();
295 
296           Spec.emplace();
297           Spec->Policy = Config::CDBSearchSpec::FixedDir;
298           Spec->FixedCDBPath = std::move(Path);
299         }
300       }
301       if (Spec)
302         Out.Apply.push_back(
303             [Spec(std::move(*Spec))](const Params &, Config &C) {
304               C.CompileFlags.CDBSearch = Spec;
305             });
306     }
307   }
308 
309   void compile(Fragment::IndexBlock &&F) {
310     if (F.Background) {
311       if (auto Val = compileEnum<Config::BackgroundPolicy>("Background",
312                                                            **F.Background)
313                          .map("Build", Config::BackgroundPolicy::Build)
314                          .map("Skip", Config::BackgroundPolicy::Skip)
315                          .value())
316         Out.Apply.push_back(
317             [Val](const Params &, Config &C) { C.Index.Background = *Val; });
318     }
319     if (F.External)
320       compile(std::move(**F.External), F.External->Range);
321   }
322 
323   void compile(Fragment::IndexBlock::ExternalBlock &&External,
324                llvm::SMRange BlockRange) {
325     if (External.Server && !Trusted) {
326       diag(Error,
327            "Remote index may not be specified by untrusted configuration. "
328            "Copy this into user config to use it.",
329            External.Server->Range);
330       return;
331     }
332 #ifndef CLANGD_ENABLE_REMOTE
333     if (External.Server) {
334       elog("Clangd isn't compiled with remote index support, ignoring Server: "
335            "{0}",
336            *External.Server);
337       External.Server.reset();
338     }
339 #endif
340     // Make sure exactly one of the Sources is set.
341     unsigned SourceCount = External.File.hasValue() +
342                            External.Server.hasValue() + *External.IsNone;
343     if (SourceCount != 1) {
344       diag(Error, "Exactly one of File, Server or None must be set.",
345            BlockRange);
346       return;
347     }
348     Config::ExternalIndexSpec Spec;
349     if (External.Server) {
350       Spec.Kind = Config::ExternalIndexSpec::Server;
351       Spec.Location = std::move(**External.Server);
352     } else if (External.File) {
353       Spec.Kind = Config::ExternalIndexSpec::File;
354       auto AbsPath = makeAbsolute(std::move(*External.File), "File",
355                                   llvm::sys::path::Style::native);
356       if (!AbsPath)
357         return;
358       Spec.Location = std::move(*AbsPath);
359     } else {
360       assert(*External.IsNone);
361       Spec.Kind = Config::ExternalIndexSpec::None;
362     }
363     if (Spec.Kind != Config::ExternalIndexSpec::None) {
364       // Make sure MountPoint is an absolute path with forward slashes.
365       if (!External.MountPoint)
366         External.MountPoint.emplace(FragmentDirectory);
367       if ((**External.MountPoint).empty()) {
368         diag(Error, "A mountpoint is required.", BlockRange);
369         return;
370       }
371       auto AbsPath = makeAbsolute(std::move(*External.MountPoint), "MountPoint",
372                                   llvm::sys::path::Style::posix);
373       if (!AbsPath)
374         return;
375       Spec.MountPoint = std::move(*AbsPath);
376     }
377     Out.Apply.push_back([Spec(std::move(Spec))](const Params &P, Config &C) {
378       if (Spec.Kind == Config::ExternalIndexSpec::None) {
379         C.Index.External.reset();
380         return;
381       }
382       if (P.Path.empty() || !pathStartsWith(Spec.MountPoint, P.Path,
383                                             llvm::sys::path::Style::posix))
384         return;
385       C.Index.External = Spec;
386       // Disable background indexing for the files under the mountpoint.
387       // Note that this will overwrite statements in any previous fragments
388       // (including the current one).
389       C.Index.Background = Config::BackgroundPolicy::Skip;
390     });
391   }
392 
393   void compile(Fragment::DiagnosticsBlock &&F) {
394     std::vector<std::string> Normalized;
395     for (const auto &Suppressed : F.Suppress) {
396       if (*Suppressed == "*") {
397         Out.Apply.push_back([&](const Params &, Config &C) {
398           C.Diagnostics.SuppressAll = true;
399           C.Diagnostics.Suppress.clear();
400         });
401         return;
402       }
403       Normalized.push_back(normalizeSuppressedCode(*Suppressed).str());
404     }
405     if (!Normalized.empty())
406       Out.Apply.push_back(
407           [Normalized(std::move(Normalized))](const Params &, Config &C) {
408             if (C.Diagnostics.SuppressAll)
409               return;
410             for (llvm::StringRef N : Normalized)
411               C.Diagnostics.Suppress.insert(N);
412           });
413 
414     compile(std::move(F.ClangTidy));
415   }
416 
417   void compile(Fragment::StyleBlock &&F) {
418     if (!F.FullyQualifiedNamespaces.empty()) {
419       std::vector<std::string> FullyQualifiedNamespaces;
420       for (auto &N : F.FullyQualifiedNamespaces) {
421         // Normalize the data by dropping both leading and trailing ::
422         StringRef Namespace(*N);
423         Namespace.consume_front("::");
424         Namespace.consume_back("::");
425         FullyQualifiedNamespaces.push_back(Namespace.str());
426       }
427       Out.Apply.push_back([FullyQualifiedNamespaces(
428                               std::move(FullyQualifiedNamespaces))](
429                               const Params &, Config &C) {
430         C.Style.FullyQualifiedNamespaces.insert(
431             C.Style.FullyQualifiedNamespaces.begin(),
432             FullyQualifiedNamespaces.begin(), FullyQualifiedNamespaces.end());
433       });
434     }
435   }
436 
437   void appendTidyCheckSpec(std::string &CurSpec,
438                            const Located<std::string> &Arg, bool IsPositive) {
439     StringRef Str = StringRef(*Arg).trim();
440     // Don't support negating here, its handled if the item is in the Add or
441     // Remove list.
442     if (Str.startswith("-") || Str.contains(',')) {
443       diag(Error, "Invalid clang-tidy check name", Arg.Range);
444       return;
445     }
446     if (!Str.contains('*') && !isRegisteredTidyCheck(Str)) {
447       diag(Warning,
448            llvm::formatv("clang-tidy check '{0}' was not found", Str).str(),
449            Arg.Range);
450       return;
451     }
452     CurSpec += ',';
453     if (!IsPositive)
454       CurSpec += '-';
455     CurSpec += Str;
456   }
457 
458   void compile(Fragment::DiagnosticsBlock::ClangTidyBlock &&F) {
459     std::string Checks;
460     for (auto &CheckGlob : F.Add)
461       appendTidyCheckSpec(Checks, CheckGlob, true);
462 
463     for (auto &CheckGlob : F.Remove)
464       appendTidyCheckSpec(Checks, CheckGlob, false);
465 
466     if (!Checks.empty())
467       Out.Apply.push_back(
468           [Checks = std::move(Checks)](const Params &, Config &C) {
469             C.Diagnostics.ClangTidy.Checks.append(
470                 Checks,
471                 C.Diagnostics.ClangTidy.Checks.empty() ? /*skip comma*/ 1 : 0,
472                 std::string::npos);
473           });
474     if (!F.CheckOptions.empty()) {
475       std::vector<std::pair<std::string, std::string>> CheckOptions;
476       for (auto &Opt : F.CheckOptions)
477         CheckOptions.emplace_back(std::move(*Opt.first),
478                                   std::move(*Opt.second));
479       Out.Apply.push_back(
480           [CheckOptions = std::move(CheckOptions)](const Params &, Config &C) {
481             for (auto &StringPair : CheckOptions)
482               C.Diagnostics.ClangTidy.CheckOptions.insert_or_assign(
483                   StringPair.first, StringPair.second);
484           });
485     }
486   }
487 
488   void compile(Fragment::CompletionBlock &&F) {
489     if (F.AllScopes) {
490       Out.Apply.push_back(
491           [AllScopes(**F.AllScopes)](const Params &, Config &C) {
492             C.Completion.AllScopes = AllScopes;
493           });
494     }
495   }
496 
497   constexpr static llvm::SourceMgr::DiagKind Error = llvm::SourceMgr::DK_Error;
498   constexpr static llvm::SourceMgr::DiagKind Warning =
499       llvm::SourceMgr::DK_Warning;
500   void diag(llvm::SourceMgr::DiagKind Kind, llvm::StringRef Message,
501             llvm::SMRange Range) {
502     if (Range.isValid() && SourceMgr != nullptr)
503       Diagnostic(SourceMgr->GetMessage(Range.Start, Kind, Message, Range));
504     else
505       Diagnostic(llvm::SMDiagnostic("", Kind, Message));
506   }
507 };
508 
509 } // namespace
510 
511 CompiledFragment Fragment::compile(DiagnosticCallback D) && {
512   llvm::StringRef ConfigFile = "<unknown>";
513   std::pair<unsigned, unsigned> LineCol = {0, 0};
514   if (auto *SM = Source.Manager.get()) {
515     unsigned BufID = SM->getMainFileID();
516     LineCol = SM->getLineAndColumn(Source.Location, BufID);
517     ConfigFile = SM->getBufferInfo(BufID).Buffer->getBufferIdentifier();
518   }
519   trace::Span Tracer("ConfigCompile");
520   SPAN_ATTACH(Tracer, "ConfigFile", ConfigFile);
521   auto Result = std::make_shared<CompiledFragmentImpl>();
522   vlog("Config fragment: compiling {0}:{1} -> {2} (trusted={3})", ConfigFile,
523        LineCol.first, Result.get(), Source.Trusted);
524 
525   FragmentCompiler{*Result, D, Source.Manager.get()}.compile(std::move(*this));
526   // Return as cheaply-copyable wrapper.
527   return [Result(std::move(Result))](const Params &P, Config &C) {
528     return (*Result)(P, C);
529   };
530 }
531 
532 } // namespace config
533 } // namespace clangd
534 } // namespace clang
535