clang-tools 10.0.0

HeaderSourceSwitch.cpp
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1 //===--- HeaderSourceSwitch.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 "HeaderSourceSwitch.h"
10 #include "AST.h"
11 #include "Logger.h"
12 #include "SourceCode.h"
13 #include "index/SymbolCollector.h"
14 #include "clang/AST/Decl.h"
15
16 namespace clang {
17 namespace clangd {
18
19 llvm::Optional<Path> getCorrespondingHeaderOrSource(
20 const Path &OriginalFile,
21 llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS) {
22 llvm::StringRef SourceExtensions[] = {".cpp", ".c", ".cc", ".cxx",
23 ".c++", ".m", ".mm"};
24 llvm::StringRef HeaderExtensions[] = {".h", ".hh", ".hpp", ".hxx", ".inc"};
25
26 llvm::StringRef PathExt = llvm::sys::path::extension(OriginalFile);
27
28 // Lookup in a list of known extensions.
29 auto SourceIter =
30 llvm::find_if(SourceExtensions, [&PathExt](PathRef SourceExt) {
31 return SourceExt.equals_lower(PathExt);
32 });
33 bool IsSource = SourceIter != std::end(SourceExtensions);
34
35 auto HeaderIter =
36 llvm::find_if(HeaderExtensions, [&PathExt](PathRef HeaderExt) {
37 return HeaderExt.equals_lower(PathExt);
38 });
39 bool IsHeader = HeaderIter != std::end(HeaderExtensions);
40
41 // We can only switch between the known extensions.
42 if (!IsSource && !IsHeader)
43 return None;
44
45 // Array to lookup extensions for the switch. An opposite of where original
46 // extension was found.
47 llvm::ArrayRef<llvm::StringRef> NewExts;
48 if (IsSource)
49 NewExts = HeaderExtensions;
50 else
51 NewExts = SourceExtensions;
52
53 // Storage for the new path.
54 llvm::SmallString<128> NewPath = llvm::StringRef(OriginalFile);
55
56 // Loop through switched extension candidates.
57 for (llvm::StringRef NewExt : NewExts) {
58 llvm::sys::path::replace_extension(NewPath, NewExt);
59 if (VFS->exists(NewPath))
60 return NewPath.str().str(); // First str() to convert from SmallString to
61 // StringRef, second to convert from StringRef
62 // to std::string
63
64 // Also check NewExt in upper-case, just in case.
65 llvm::sys::path::replace_extension(NewPath, NewExt.upper());
66 if (VFS->exists(NewPath))
67 return NewPath.str().str();
68 }
69 return None;
70 }
71
72 llvm::Optional<Path> getCorrespondingHeaderOrSource(const Path &OriginalFile,
73 ParsedAST &AST,
74 const SymbolIndex *Index) {
75 if (!Index) {
76 // FIXME: use the AST to do the inference.
77 return None;
78 }
79 LookupRequest Request;
80 // Find all symbols present in the original file.
81 for (const auto *D : getIndexableLocalDecls(AST)) {
82 if (auto ID = getSymbolID(D))
83 Request.IDs.insert(*ID);
84 }
85 llvm::StringMap<int> Candidates; // Target path => score.
86 auto AwardTarget = [&](const char *TargetURI) {
87 if (auto TargetPath = URI::resolve(TargetURI, OriginalFile)) {
88 if (*TargetPath != OriginalFile) // exclude the original file.
89 ++Candidates[*TargetPath];
90 } else {
91 elog("Failed to resolve URI {0}: {1}", TargetURI, TargetPath.takeError());
92 }
93 };
94 // If we switch from a header, we are looking for the implementation
95 // file, so we use the definition loc; otherwise we look for the header file,
96 // we use the decl loc;
97 //
98 // For each symbol in the original file, we get its target location (decl or
99 // def) from the index, then award that target file.
100 bool IsHeader = isHeaderFile(OriginalFile, AST.getLangOpts());
101 Index->lookup(Request, [&](const Symbol &Sym) {
102 if (IsHeader)
103 AwardTarget(Sym.Definition.FileURI);
104 else
105 AwardTarget(Sym.CanonicalDeclaration.FileURI);
106 });
107 // FIXME: our index doesn't have any interesting information (this could be
108 // that the background-index is not finished), we should use the decl/def
109 // locations from the AST to do the inference (from .cc to .h).
110 if (Candidates.empty())
111 return None;
112
113 // Pickup the winner, who contains most of symbols.
114 // FIXME: should we use other signals (file proximity) to help score?
115 auto Best = Candidates.begin();
116 for (auto It = Candidates.begin(); It != Candidates.end(); ++It) {
117 if (It->second > Best->second)
118 Best = It;
119 else if (It->second == Best->second && It->first() < Best->first())
120 // Select the first one in the lexical order if we have multiple
121 // candidates.
122 Best = It;
123 }
124 return Path(Best->first());
125 }
126
127 std::vector<const Decl *> getIndexableLocalDecls(ParsedAST &AST) {
128 std::vector<const Decl *> Results;
129 std::function<void(Decl *)> TraverseDecl = [&](Decl *D) {
130 auto *ND = llvm::dyn_cast<NamedDecl>(D);
131 if (!ND || ND->isImplicit())
132 return;
133 if (!SymbolCollector::shouldCollectSymbol(*ND, D->getASTContext(), {},
134 /*IsMainFileSymbol=*/false))
135 return;
136 if (!llvm::isa<FunctionDecl>(ND)) {
137 // Visit the children, but we skip function decls as we are not interested
138 // in the function body.
139 if (auto *Scope = llvm::dyn_cast<DeclContext>(ND)) {
140 for (auto *D : Scope->decls())
141 TraverseDecl(D);
142 }
143 }
144 if (llvm::isa<NamespaceDecl>(D))
145 return; // namespace is indexable, but we're not interested.
146 Results.push_back(D);
147 };
148 // Traverses the ParsedAST directly to collect all decls present in the main
149 // file.
150 for (auto *TopLevel : AST.getLocalTopLevelDecls())
151 TraverseDecl(TopLevel);
152 return Results;
153 }
154
155 } // namespace clangd
156 } // namespace clang
clang::clangd::SymbolIndex::lookup
virtual void lookup(const LookupRequest &Req, llvm::function_ref< void(const Symbol &)> Callback) const =0
Looks up symbols with any of the given symbol IDs and applies Callback on each matched symbol...
Decl
const FunctionDecl * Decl
Definition: AvoidBindCheck.cpp:93
AST.h
clang::clangd::ParsedAST::getLangOpts
const LangOptions & getLangOpts() const
Definition: ParsedAST.h:80
clang::clangd::getSymbolID
llvm::Optional< SymbolID > getSymbolID(const Decl *D)
Gets the symbol ID for a declaration, if possible.
Definition: AST.cpp:286
VFS
llvm::IntrusiveRefCntPtr< llvm::vfs::FileSystem > VFS
Definition: CodeComplete.cpp:1023
clang::clangd::SymbolIndex
Interface for symbol indexes that can be used for searching or matching symbols among a set of symbol...
Definition: Index.h:85
SourceCode.h
clang::clangd::LookupRequest::IDs
llvm::DenseSet< SymbolID > IDs
Definition: Index.h:64
clang::clangd::PathRef
llvm::StringRef PathRef
A typedef to represent a ref to file path.
Definition: Path.h:23
Results
std::vector< CodeCompletionResult > Results
Definition: CodeComplete.cpp:689
clang::clangd::ParsedAST::getLocalTopLevelDecls
ArrayRef< Decl * > getLocalTopLevelDecls()
This function returns top-level decls present in the main file of the AST.
Definition: ParsedAST.cpp:440
clang::clangd::elog
void elog(const char *Fmt, Ts &&... Vals)
Definition: Logger.h:56
clang::clangd::getIndexableLocalDecls
std::vector< const Decl * > getIndexableLocalDecls(ParsedAST &AST)
Returns all indexable decls that are present in the main file of the AST.
Definition: HeaderSourceSwitch.cpp:127
clang::clangd::Symbol::Definition
SymbolLocation Definition
The location of the symbol&#39;s definition, if one was found.
Definition: Symbol.h:47
HeaderSourceSwitch.h
clang::clangd::Path
std::string Path
A typedef to represent a file path.
Definition: Path.h:20
clang::clangd::Symbol::CanonicalDeclaration
SymbolLocation CanonicalDeclaration
The location of the preferred declaration of the symbol.
Definition: Symbol.h:56
clang::clangd::ParsedAST
Stores and provides access to parsed AST.
Definition: ParsedAST.h:46
Logger.h
clang::clangd::SymbolCollector::shouldCollectSymbol
static bool shouldCollectSymbol(const NamedDecl &ND, const ASTContext &ASTCtx, const Options &Opts, bool IsMainFileSymbol)
Returns true is ND should be collected.
Definition: SymbolCollector.cpp:202
clang::clangd::Symbol
The class presents a C++ symbol, e.g.
Definition: Symbol.h:36
clang::clangd::getCorrespondingHeaderOrSource
llvm::Optional< Path > getCorrespondingHeaderOrSource(const Path &OriginalFile, llvm::IntrusiveRefCntPtr< llvm::vfs::FileSystem > VFS)
Given a header file, returns the best matching source file, and vice visa.
Definition: HeaderSourceSwitch.cpp:19
clang::clangd::LookupRequest
Definition: Index.h:63
clang
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Definition: ApplyReplacements.h:27
SymbolCollector.h
clang::clangd::isHeaderFile
bool isHeaderFile(llvm::StringRef FileName, llvm::Optional< LangOptions > LangOpts)
Infers whether this is a header from the FileName and LangOpts (if presents).
Definition: SourceCode.cpp:1118
clang::clangd::URI::resolve
static llvm::Expected< std::string > resolve(const URI &U, llvm::StringRef HintPath="")
Resolves the absolute path of U.
Definition: URI.cpp:233
clang::clangd::SymbolLocation::FileURI
const char * FileURI
Definition: SymbolLocation.h:63
Index
const SymbolIndex * Index
Definition: Dexp.cpp:84