1 //===--- IncludeFixer.h ------------------------------------------*- 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 #ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_INCLUDEFIXER_H
10 #define LLVM_CLANG_TOOLS_EXTRA_CLANGD_INCLUDEFIXER_H
11 
12 #include "Diagnostics.h"
13 #include "Headers.h"
14 #include "index/Index.h"
15 #include "index/Symbol.h"
16 #include "clang/AST/Type.h"
17 #include "clang/Basic/Diagnostic.h"
18 #include "clang/Basic/SourceLocation.h"
19 #include "clang/Sema/ExternalSemaSource.h"
20 #include "llvm/ADT/DenseMap.h"
21 #include "llvm/ADT/IntrusiveRefCntPtr.h"
22 #include "llvm/ADT/Optional.h"
23 #include "llvm/ADT/StringMap.h"
24 #include "llvm/ADT/StringRef.h"
25 #include <memory>
26 
27 namespace clang {
28 namespace clangd {
29 
30 /// Attempts to recover from error diagnostics by suggesting include insertion
31 /// fixes. For example, member access into incomplete type can be fixes by
32 /// include headers with the definition.
33 class IncludeFixer {
34 public:
IncludeFixer(llvm::StringRef File,std::shared_ptr<IncludeInserter> Inserter,const SymbolIndex & Index,unsigned IndexRequestLimit)35   IncludeFixer(llvm::StringRef File, std::shared_ptr<IncludeInserter> Inserter,
36                const SymbolIndex &Index, unsigned IndexRequestLimit)
37       : File(File), Inserter(std::move(Inserter)), Index(Index),
38         IndexRequestLimit(IndexRequestLimit) {}
39 
40   /// Returns include insertions that can potentially recover the diagnostic.
41   /// If Info is a note and fixes are returned, they should *replace* the note.
42   std::vector<Fix> fix(DiagnosticsEngine::Level DiagLevel,
43                        const clang::Diagnostic &Info) const;
44 
45   /// Returns an ExternalSemaSource that records failed name lookups in Sema.
46   /// This allows IncludeFixer to suggest inserting headers that define those
47   /// names.
48   llvm::IntrusiveRefCntPtr<ExternalSemaSource> unresolvedNameRecorder();
49 
50 private:
51   /// Attempts to recover diagnostic caused by an incomplete type \p T.
52   std::vector<Fix> fixIncompleteType(const Type &T) const;
53 
54   /// Generates header insertion fixes for all symbols. Fixes are deduplicated.
55   std::vector<Fix> fixesForSymbols(const SymbolSlab &Syms) const;
56 
57   llvm::Optional<Fix> insertHeader(llvm::StringRef Name,
58                                    llvm::StringRef Symbol = "") const;
59 
60   struct UnresolvedName {
61     std::string Name;   // E.g. "X" in foo::X.
62     SourceLocation Loc; // Start location of the unresolved name.
63     std::vector<std::string> Scopes; // Namespace scopes we should search in.
64   };
65 
66   /// Records the last unresolved name seen by Sema.
67   class UnresolvedNameRecorder;
68 
69   /// Attempts to fix the unresolved name associated with the current
70   /// diagnostic. We assume a diagnostic is caused by a unresolved name when
71   /// they have the same source location and the unresolved name is the last
72   /// one we've seen during the Sema run.
73   std::vector<Fix> fixUnresolvedName() const;
74 
75   std::string File;
76   std::shared_ptr<IncludeInserter> Inserter;
77   const SymbolIndex &Index;
78   const unsigned IndexRequestLimit; // Make at most 5 index requests.
79   mutable unsigned IndexRequestCount = 0;
80 
81   // These collect the last unresolved name so that we can associate it with the
82   // diagnostic.
83   llvm::Optional<UnresolvedName> LastUnresolvedName;
84 
85   // There can be multiple diagnostics that are caused by the same unresolved
86   // name or incomplete type in one parse, especially when code is
87   // copy-and-pasted without #includes. We cache the index results based on
88   // index requests.
89   mutable llvm::StringMap<SymbolSlab> FuzzyFindCache;
90   mutable llvm::DenseMap<SymbolID, SymbolSlab> LookupCache;
91   // Returns None if the number of index requests has reached the limit.
92   llvm::Optional<const SymbolSlab *>
93   fuzzyFindCached(const FuzzyFindRequest &Req) const;
94   llvm::Optional<const SymbolSlab *> lookupCached(const SymbolID &ID) const;
95 };
96 
97 } // namespace clangd
98 } // namespace clang
99 
100 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANGD_INCLUDEFIXER_H
101