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