xref: /llvm-project/clang-tools-extra/clangd/Compiler.cpp (revision df9a14d7bbf1180e4f1474254c9d7ed6bcb4ce55)
1 //===--- Compiler.cpp --------------------------------------------*- C++-*-===//
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 #include "Compiler.h"
10 #include "support/Logger.h"
11 #include "clang/Basic/TargetInfo.h"
12 #include "clang/Frontend/CompilerInvocation.h"
13 #include "clang/Lex/PreprocessorOptions.h"
14 #include "clang/Serialization/PCHContainerOperations.h"
15 #include "llvm/ADT/StringRef.h"
16 
17 namespace clang {
18 namespace clangd {
19 
20 void IgnoreDiagnostics::log(DiagnosticsEngine::Level DiagLevel,
21                             const clang::Diagnostic &Info) {
22   // FIXME: format lazily, in case vlog is off.
23   llvm::SmallString<64> Message;
24   Info.FormatDiagnostic(Message);
25 
26   llvm::SmallString<64> Location;
27   if (Info.hasSourceManager() && Info.getLocation().isValid()) {
28     auto &SourceMgr = Info.getSourceManager();
29     auto Loc = SourceMgr.getFileLoc(Info.getLocation());
30     llvm::raw_svector_ostream OS(Location);
31     Loc.print(OS, SourceMgr);
32     OS << ":";
33   }
34 
35   clangd::vlog("Ignored diagnostic. {0}{1}", Location, Message);
36 }
37 
38 void IgnoreDiagnostics::HandleDiagnostic(DiagnosticsEngine::Level DiagLevel,
39                                          const clang::Diagnostic &Info) {
40   IgnoreDiagnostics::log(DiagLevel, Info);
41 }
42 
43 static bool AllowCrashPragmasForTest = false;
44 void allowCrashPragmasForTest() { AllowCrashPragmasForTest = true; }
45 
46 void disableUnsupportedOptions(CompilerInvocation &CI) {
47   // Disable "clang -verify" diagnostics, they are rarely useful in clangd, and
48   // our compiler invocation set-up doesn't seem to work with it (leading
49   // assertions in VerifyDiagnosticConsumer).
50   CI.getDiagnosticOpts().VerifyDiagnostics = false;
51   CI.getDiagnosticOpts().ShowColors = false;
52 
53   // Disable any dependency outputting, we don't want to generate files or write
54   // to stdout/stderr.
55   CI.getDependencyOutputOpts().ShowIncludesDest = ShowIncludesDestination::None;
56   CI.getDependencyOutputOpts().OutputFile.clear();
57   CI.getDependencyOutputOpts().HeaderIncludeOutputFile.clear();
58   CI.getDependencyOutputOpts().DOTOutputFile.clear();
59   CI.getDependencyOutputOpts().ModuleDependencyOutputDir.clear();
60 
61   // Disable any pch generation/usage operations. Since serialized preamble
62   // format is unstable, using an incompatible one might result in unexpected
63   // behaviours, including crashes.
64   CI.getPreprocessorOpts().ImplicitPCHInclude.clear();
65   CI.getPreprocessorOpts().PrecompiledPreambleBytes = {0, false};
66   CI.getPreprocessorOpts().PCHThroughHeader.clear();
67   CI.getPreprocessorOpts().PCHWithHdrStop = false;
68   CI.getPreprocessorOpts().PCHWithHdrStopCreate = false;
69   // Don't crash on `#pragma clang __debug parser_crash`
70   if (!AllowCrashPragmasForTest)
71     CI.getPreprocessorOpts().DisablePragmaDebugCrash = true;
72 
73   // Always default to raw container format as clangd doesn't registry any other
74   // and clang dies when faced with unknown formats.
75   CI.getHeaderSearchOpts().ModuleFormat =
76       PCHContainerOperations().getRawReader().getFormats().front().str();
77 
78   CI.getFrontendOpts().Plugins.clear();
79   CI.getFrontendOpts().AddPluginActions.clear();
80   CI.getFrontendOpts().PluginArgs.clear();
81   CI.getFrontendOpts().ProgramAction = frontend::ParseSyntaxOnly;
82   CI.getFrontendOpts().ActionName.clear();
83 
84   // These options mostly affect codegen, and aren't relevant to clangd. And
85   // clang will die immediately when these files are not existed.
86   // Disable these uninteresting options to make clangd more robust.
87   CI.getLangOpts().NoSanitizeFiles.clear();
88   CI.getLangOpts().XRayAttrListFiles.clear();
89   CI.getLangOpts().ProfileListFiles.clear();
90   CI.getLangOpts().XRayAlwaysInstrumentFiles.clear();
91   CI.getLangOpts().XRayNeverInstrumentFiles.clear();
92 }
93 
94 std::unique_ptr<CompilerInvocation>
95 buildCompilerInvocation(const ParseInputs &Inputs, clang::DiagnosticConsumer &D,
96                         std::vector<std::string> *CC1Args) {
97   llvm::ArrayRef<std::string> Argv = Inputs.CompileCommand.CommandLine;
98   if (Argv.empty())
99     return nullptr;
100   std::vector<const char *> ArgStrs;
101   ArgStrs.reserve(Argv.size() + 1);
102   // In asserts builds, CompilerInvocation redundantly reads/parses cc1 args as
103   // a sanity test. This is not useful to clangd, and costs 10% of test time.
104   // To avoid mismatches between assert/production builds, disable it always.
105   ArgStrs = {Argv.front().c_str(), "-Xclang", "-no-round-trip-args"};
106   for (const auto &S : Argv.drop_front())
107     ArgStrs.push_back(S.c_str());
108 
109   CreateInvocationOptions CIOpts;
110   CIOpts.VFS = Inputs.TFS->view(Inputs.CompileCommand.Directory);
111   CIOpts.CC1Args = CC1Args;
112   CIOpts.RecoverOnError = true;
113   CIOpts.Diags = CompilerInstance::createDiagnostics(
114       *CIOpts.VFS, new DiagnosticOptions, &D, false);
115   CIOpts.ProbePrecompiled = false;
116   std::unique_ptr<CompilerInvocation> CI = createInvocation(ArgStrs, CIOpts);
117   if (!CI)
118     return nullptr;
119   // createInvocationFromCommandLine sets DisableFree.
120   CI->getFrontendOpts().DisableFree = false;
121   CI->getLangOpts().CommentOpts.ParseAllComments = true;
122   CI->getLangOpts().RetainCommentsFromSystemHeaders = true;
123 
124   disableUnsupportedOptions(*CI);
125   return CI;
126 }
127 
128 std::unique_ptr<CompilerInstance>
129 prepareCompilerInstance(std::unique_ptr<clang::CompilerInvocation> CI,
130                         const PrecompiledPreamble *Preamble,
131                         std::unique_ptr<llvm::MemoryBuffer> Buffer,
132                         llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS,
133                         DiagnosticConsumer &DiagsClient) {
134   assert(VFS && "VFS is null");
135   assert(!CI->getPreprocessorOpts().RetainRemappedFileBuffers &&
136          "Setting RetainRemappedFileBuffers to true will cause a memory leak "
137          "of ContentsBuffer");
138 
139   // NOTE: we use Buffer.get() when adding remapped files, so we have to make
140   // sure it will be released if no error is emitted.
141   if (Preamble) {
142     Preamble->OverridePreamble(*CI, VFS, Buffer.get());
143   } else {
144     CI->getPreprocessorOpts().addRemappedFile(
145         CI->getFrontendOpts().Inputs[0].getFile(), Buffer.get());
146   }
147 
148   auto Clang = std::make_unique<CompilerInstance>(
149       std::make_shared<PCHContainerOperations>());
150   Clang->setInvocation(std::move(CI));
151   Clang->createDiagnostics(*VFS, &DiagsClient, false);
152 
153   if (auto VFSWithRemapping = createVFSFromCompilerInvocation(
154           Clang->getInvocation(), Clang->getDiagnostics(), VFS))
155     VFS = VFSWithRemapping;
156   Clang->createFileManager(VFS);
157 
158   if (!Clang->createTarget())
159     return nullptr;
160 
161   // RemappedFileBuffers will handle the lifetime of the Buffer pointer,
162   // release it.
163   Buffer.release();
164   return Clang;
165 }
166 
167 } // namespace clangd
168 } // namespace clang
169