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().getFormat().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 
85 std::unique_ptr<CompilerInvocation>
86 buildCompilerInvocation(const ParseInputs &Inputs, clang::DiagnosticConsumer &D,
87                         std::vector<std::string> *CC1Args) {
88   if (Inputs.CompileCommand.CommandLine.empty())
89     return nullptr;
90   std::vector<const char *> ArgStrs;
91   for (const auto &S : Inputs.CompileCommand.CommandLine)
92     ArgStrs.push_back(S.c_str());
93 
94   auto VFS = Inputs.TFS->view(Inputs.CompileCommand.Directory);
95   llvm::IntrusiveRefCntPtr<DiagnosticsEngine> CommandLineDiagsEngine =
96       CompilerInstance::createDiagnostics(new DiagnosticOptions, &D, false);
97   std::unique_ptr<CompilerInvocation> CI = createInvocationFromCommandLine(
98       ArgStrs, CommandLineDiagsEngine, std::move(VFS),
99       /*ShouldRecoverOnErrors=*/true, CC1Args);
100   if (!CI)
101     return nullptr;
102   // createInvocationFromCommandLine sets DisableFree.
103   CI->getFrontendOpts().DisableFree = false;
104   CI->getLangOpts()->CommentOpts.ParseAllComments = true;
105   CI->getLangOpts()->RetainCommentsFromSystemHeaders = true;
106 
107   disableUnsupportedOptions(*CI);
108   return CI;
109 }
110 
111 std::unique_ptr<CompilerInstance>
112 prepareCompilerInstance(std::unique_ptr<clang::CompilerInvocation> CI,
113                         const PrecompiledPreamble *Preamble,
114                         std::unique_ptr<llvm::MemoryBuffer> Buffer,
115                         llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS,
116                         DiagnosticConsumer &DiagsClient) {
117   assert(VFS && "VFS is null");
118   assert(!CI->getPreprocessorOpts().RetainRemappedFileBuffers &&
119          "Setting RetainRemappedFileBuffers to true will cause a memory leak "
120          "of ContentsBuffer");
121 
122   // NOTE: we use Buffer.get() when adding remapped files, so we have to make
123   // sure it will be released if no error is emitted.
124   if (Preamble) {
125     Preamble->OverridePreamble(*CI, VFS, Buffer.get());
126   } else {
127     CI->getPreprocessorOpts().addRemappedFile(
128         CI->getFrontendOpts().Inputs[0].getFile(), Buffer.get());
129   }
130 
131   auto Clang = std::make_unique<CompilerInstance>(
132       std::make_shared<PCHContainerOperations>());
133   Clang->setInvocation(std::move(CI));
134   Clang->createDiagnostics(&DiagsClient, false);
135 
136   if (auto VFSWithRemapping = createVFSFromCompilerInvocation(
137           Clang->getInvocation(), Clang->getDiagnostics(), VFS))
138     VFS = VFSWithRemapping;
139   Clang->createFileManager(VFS);
140 
141   if (!Clang->createTarget())
142     return nullptr;
143 
144   // RemappedFileBuffers will handle the lifetime of the Buffer pointer,
145   // release it.
146   Buffer.release();
147   return Clang;
148 }
149 
150 } // namespace clangd
151 } // namespace clang
152