1 //===--- Compiler.cpp -------------------------------------------*- C++-*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===---------------------------------------------------------------------===//
9 
10 #include "Compiler.h"
11 #include "clang/Basic/TargetInfo.h"
12 #include "clang/Lex/PreprocessorOptions.h"
13 
14 namespace clang {
15 namespace clangd {
16 
17 /// Creates a CompilerInstance from \p CI, with main buffer overriden to \p
18 /// Buffer and arguments to read the PCH from \p Preamble, if \p Preamble is not
19 /// null. Note that vfs::FileSystem inside returned instance may differ from \p
20 /// VFS if additional file remapping were set in command-line arguments.
21 /// On some errors, returns null. When non-null value is returned, it's expected
22 /// to be consumed by the FrontendAction as it will have a pointer to the \p
23 /// Buffer that will only be deleted if BeginSourceFile is called.
24 std::unique_ptr<CompilerInstance>
25 prepareCompilerInstance(std::unique_ptr<clang::CompilerInvocation> CI,
26                         const PrecompiledPreamble *Preamble,
27                         std::unique_ptr<llvm::MemoryBuffer> Buffer,
28                         std::shared_ptr<PCHContainerOperations> PCHs,
29                         IntrusiveRefCntPtr<vfs::FileSystem> VFS,
30                         DiagnosticConsumer &DiagsClient) {
31   assert(VFS && "VFS is null");
32   assert(!CI->getPreprocessorOpts().RetainRemappedFileBuffers &&
33          "Setting RetainRemappedFileBuffers to true will cause a memory leak "
34          "of ContentsBuffer");
35 
36   // NOTE: we use Buffer.get() when adding remapped files, so we have to make
37   // sure it will be released if no error is emitted.
38   if (Preamble) {
39     Preamble->AddImplicitPreamble(*CI, VFS, Buffer.get());
40   } else {
41     CI->getPreprocessorOpts().addRemappedFile(
42         CI->getFrontendOpts().Inputs[0].getFile(), Buffer.get());
43   }
44 
45   auto Clang = llvm::make_unique<CompilerInstance>(PCHs);
46   Clang->setInvocation(std::move(CI));
47   Clang->createDiagnostics(&DiagsClient, false);
48 
49   if (auto VFSWithRemapping = createVFSFromCompilerInvocation(
50           Clang->getInvocation(), Clang->getDiagnostics(), VFS))
51     VFS = VFSWithRemapping;
52   Clang->setVirtualFileSystem(VFS);
53 
54   Clang->setTarget(TargetInfo::CreateTargetInfo(
55       Clang->getDiagnostics(), Clang->getInvocation().TargetOpts));
56   if (!Clang->hasTarget())
57     return nullptr;
58 
59   // RemappedFileBuffers will handle the lifetime of the Buffer pointer,
60   // release it.
61   Buffer.release();
62   return Clang;
63 }
64 
65 } // namespace clangd
66 } // namespace clang
67