1 //===--- PTHManager.h - Manager object for PTH processing -------*- 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 //  This file defines the PTHManager interface.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_CLANG_LEX_PTHMANAGER_H
15 #define LLVM_CLANG_LEX_PTHMANAGER_H
16 
17 #include "clang/Basic/Diagnostic.h"
18 #include "clang/Basic/IdentifierTable.h"
19 #include "clang/Basic/LangOptions.h"
20 #include "clang/Lex/PTHLexer.h"
21 #include "llvm/ADT/DenseMap.h"
22 #include "llvm/ADT/STLExtras.h"
23 #include "llvm/Support/Allocator.h"
24 #include "llvm/Support/OnDiskHashTable.h"
25 #include <string>
26 
27 namespace llvm {
28   class MemoryBuffer;
29 }
30 
31 namespace clang {
32 
33 class FileEntry;
34 class PTHLexer;
35 class DiagnosticsEngine;
36 class FileSystemStatCache;
37 
38 class PTHManager : public IdentifierInfoLookup {
39   friend class PTHLexer;
40 
41   friend class PTHStatCache;
42 
43   class PTHStringLookupTrait;
44   class PTHFileLookupTrait;
45   typedef llvm::OnDiskChainedHashTable<PTHStringLookupTrait> PTHStringIdLookup;
46   typedef llvm::OnDiskChainedHashTable<PTHFileLookupTrait> PTHFileLookup;
47 
48   /// The memory mapped PTH file.
49   std::unique_ptr<const llvm::MemoryBuffer> Buf;
50 
51   /// Alloc - Allocator used for IdentifierInfo objects.
52   llvm::BumpPtrAllocator Alloc;
53 
54   /// IdMap - A lazily generated cache mapping from persistent identifiers to
55   ///  IdentifierInfo*.
56   std::unique_ptr<IdentifierInfo *[], llvm::FreeDeleter> PerIDCache;
57 
58   /// FileLookup - Abstract data structure used for mapping between files
59   ///  and token data in the PTH file.
60   std::unique_ptr<PTHFileLookup> FileLookup;
61 
62   /// IdDataTable - Array representing the mapping from persistent IDs to the
63   ///  data offset within the PTH file containing the information to
64   ///  reconsitute an IdentifierInfo.
65   const unsigned char* const IdDataTable;
66 
67   /// SortedIdTable - Abstract data structure mapping from strings to
68   ///  persistent IDs.  This is used by get().
69   std::unique_ptr<PTHStringIdLookup> StringIdLookup;
70 
71   /// NumIds - The number of identifiers in the PTH file.
72   const unsigned NumIds;
73 
74   /// PP - The Preprocessor object that will use this PTHManager to create
75   ///  PTHLexer objects.
76   Preprocessor* PP;
77 
78   /// SpellingBase - The base offset within the PTH memory buffer that
79   ///  contains the cached spellings for literals.
80   const unsigned char* const SpellingBase;
81 
82   /// OriginalSourceFile - A null-terminated C-string that specifies the name
83   ///  if the file (if any) that was to used to generate the PTH cache.
84   const char* OriginalSourceFile;
85 
86   /// This constructor is intended to only be called by the static 'Create'
87   /// method.
88   PTHManager(std::unique_ptr<const llvm::MemoryBuffer> buf,
89              std::unique_ptr<PTHFileLookup> fileLookup,
90              const unsigned char *idDataTable,
91              std::unique_ptr<IdentifierInfo *[], llvm::FreeDeleter> perIDCache,
92              std::unique_ptr<PTHStringIdLookup> stringIdLookup, unsigned numIds,
93              const unsigned char *spellingBase, const char *originalSourceFile);
94 
95   PTHManager(const PTHManager &) = delete;
96   void operator=(const PTHManager &) = delete;
97 
98   /// getSpellingAtPTHOffset - Used by PTHLexer classes to get the cached
99   ///  spelling for a token.
100   unsigned getSpellingAtPTHOffset(unsigned PTHOffset, const char*& Buffer);
101 
102   /// GetIdentifierInfo - Used to reconstruct IdentifierInfo objects from the
103   ///  PTH file.
GetIdentifierInfo(unsigned PersistentID)104   inline IdentifierInfo* GetIdentifierInfo(unsigned PersistentID) {
105     // Check if the IdentifierInfo has already been resolved.
106     if (IdentifierInfo* II = PerIDCache[PersistentID])
107       return II;
108     return LazilyCreateIdentifierInfo(PersistentID);
109   }
110   IdentifierInfo* LazilyCreateIdentifierInfo(unsigned PersistentID);
111 
112 public:
113   // The current PTH version.
114   enum { Version = 10 };
115 
116   ~PTHManager() override;
117 
118   /// getOriginalSourceFile - Return the full path to the original header
119   ///  file name that was used to generate the PTH cache.
getOriginalSourceFile()120   const char* getOriginalSourceFile() const {
121     return OriginalSourceFile;
122   }
123 
124   /// get - Return the identifier token info for the specified named identifier.
125   ///  Unlike the version in IdentifierTable, this returns a pointer instead
126   ///  of a reference.  If the pointer is NULL then the IdentifierInfo cannot
127   ///  be found.
128   IdentifierInfo *get(StringRef Name) override;
129 
130   /// Create - This method creates PTHManager objects.  The 'file' argument
131   ///  is the name of the PTH file.  This method returns NULL upon failure.
132   static PTHManager *Create(StringRef file, DiagnosticsEngine &Diags);
133 
setPreprocessor(Preprocessor * pp)134   void setPreprocessor(Preprocessor *pp) { PP = pp; }
135 
136   /// CreateLexer - Return a PTHLexer that "lexes" the cached tokens for the
137   ///  specified file.  This method returns NULL if no cached tokens exist.
138   ///  It is the responsibility of the caller to 'delete' the returned object.
139   PTHLexer *CreateLexer(FileID FID);
140 
141   /// createStatCache - Returns a FileSystemStatCache object for use with
142   ///  FileManager objects.  These objects use the PTH data to speed up
143   ///  calls to stat by memoizing their results from when the PTH file
144   ///  was generated.
145   std::unique_ptr<FileSystemStatCache> createStatCache();
146 };
147 
148 }  // end namespace clang
149 
150 #endif
151