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      1 //===--- ModuleManager.cpp - Module Manager ---------------------*- 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 ModuleManager class, which manages a set of loaded
     11 //  modules for the ASTReader.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #ifndef LLVM_CLANG_SERIALIZATION_MODULE_MANAGER_H
     16 #define LLVM_CLANG_SERIALIZATION_MODULE_MANAGER_H
     17 
     18 #include "clang/Basic/FileManager.h"
     19 #include "clang/Serialization/Module.h"
     20 #include "llvm/ADT/DenseMap.h"
     21 
     22 namespace clang {
     23 
     24 class GlobalModuleIndex;
     25 class ModuleMap;
     26 
     27 namespace serialization {
     28 
     29 /// \brief Manages the set of modules loaded by an AST reader.
     30 class ModuleManager {
     31   /// \brief The chain of AST files. The first entry is the one named by the
     32   /// user, the last one is the one that doesn't depend on anything further.
     33   SmallVector<ModuleFile *, 2> Chain;
     34 
     35   /// \brief All loaded modules, indexed by name.
     36   llvm::DenseMap<const FileEntry *, ModuleFile *> Modules;
     37 
     38   /// \brief FileManager that handles translating between filenames and
     39   /// FileEntry *.
     40   FileManager &FileMgr;
     41 
     42   /// \brief A lookup of in-memory (virtual file) buffers
     43   llvm::DenseMap<const FileEntry *, llvm::MemoryBuffer *> InMemoryBuffers;
     44 
     45   /// \brief The visitation order.
     46   SmallVector<ModuleFile *, 4> VisitOrder;
     47 
     48   /// \brief The list of module files that both we and the global module index
     49   /// know about.
     50   ///
     51   /// Either the global index or the module manager may have modules that the
     52   /// other does not know about, because the global index can be out-of-date
     53   /// (in which case the module manager could have modules it does not) and
     54   /// this particular translation unit might not have loaded all of the modules
     55   /// known to the global index.
     56   SmallVector<ModuleFile *, 4> ModulesInCommonWithGlobalIndex;
     57 
     58   /// \brief The global module index, if one is attached.
     59   ///
     60   /// The global module index will actually be owned by the ASTReader; this is
     61   /// just an non-owning pointer.
     62   GlobalModuleIndex *GlobalIndex;
     63 
     64   /// \brief State used by the "visit" operation to avoid malloc traffic in
     65   /// calls to visit().
     66   struct VisitState {
     67     explicit VisitState(unsigned N)
     68       : VisitNumber(N, 0), NextVisitNumber(1), NextState(0)
     69     {
     70       Stack.reserve(N);
     71     }
     72 
     73     ~VisitState() {
     74       delete NextState;
     75     }
     76 
     77     /// \brief The stack used when marking the imports of a particular module
     78     /// as not-to-be-visited.
     79     SmallVector<ModuleFile *, 4> Stack;
     80 
     81     /// \brief The visit number of each module file, which indicates when
     82     /// this module file was last visited.
     83     SmallVector<unsigned, 4> VisitNumber;
     84 
     85     /// \brief The next visit number to use to mark visited module files.
     86     unsigned NextVisitNumber;
     87 
     88     /// \brief The next visit state.
     89     VisitState *NextState;
     90   };
     91 
     92   /// \brief The first visit() state in the chain.
     93   VisitState *FirstVisitState;
     94 
     95   VisitState *allocateVisitState();
     96   void returnVisitState(VisitState *State);
     97 
     98 public:
     99   typedef SmallVectorImpl<ModuleFile*>::iterator ModuleIterator;
    100   typedef SmallVectorImpl<ModuleFile*>::const_iterator ModuleConstIterator;
    101   typedef SmallVectorImpl<ModuleFile*>::reverse_iterator ModuleReverseIterator;
    102   typedef std::pair<uint32_t, StringRef> ModuleOffset;
    103 
    104   explicit ModuleManager(FileManager &FileMgr);
    105   ~ModuleManager();
    106 
    107   /// \brief Forward iterator to traverse all loaded modules.  This is reverse
    108   /// source-order.
    109   ModuleIterator begin() { return Chain.begin(); }
    110   /// \brief Forward iterator end-point to traverse all loaded modules
    111   ModuleIterator end() { return Chain.end(); }
    112 
    113   /// \brief Const forward iterator to traverse all loaded modules.  This is
    114   /// in reverse source-order.
    115   ModuleConstIterator begin() const { return Chain.begin(); }
    116   /// \brief Const forward iterator end-point to traverse all loaded modules
    117   ModuleConstIterator end() const { return Chain.end(); }
    118 
    119   /// \brief Reverse iterator to traverse all loaded modules.  This is in
    120   /// source order.
    121   ModuleReverseIterator rbegin() { return Chain.rbegin(); }
    122   /// \brief Reverse iterator end-point to traverse all loaded modules.
    123   ModuleReverseIterator rend() { return Chain.rend(); }
    124 
    125   /// \brief Returns the primary module associated with the manager, that is,
    126   /// the first module loaded
    127   ModuleFile &getPrimaryModule() { return *Chain[0]; }
    128 
    129   /// \brief Returns the primary module associated with the manager, that is,
    130   /// the first module loaded.
    131   ModuleFile &getPrimaryModule() const { return *Chain[0]; }
    132 
    133   /// \brief Returns the module associated with the given index
    134   ModuleFile &operator[](unsigned Index) const { return *Chain[Index]; }
    135 
    136   /// \brief Returns the module associated with the given name
    137   ModuleFile *lookup(StringRef Name);
    138 
    139   /// \brief Returns the module associated with the given module file.
    140   ModuleFile *lookup(const FileEntry *File);
    141 
    142   /// \brief Returns the in-memory (virtual file) buffer with the given name
    143   llvm::MemoryBuffer *lookupBuffer(StringRef Name);
    144 
    145   /// \brief Number of modules loaded
    146   unsigned size() const { return Chain.size(); }
    147 
    148   /// \brief The result of attempting to add a new module.
    149   enum AddModuleResult {
    150     /// \brief The module file had already been loaded.
    151     AlreadyLoaded,
    152     /// \brief The module file was just loaded in response to this call.
    153     NewlyLoaded,
    154     /// \brief The module file is missing.
    155     Missing,
    156     /// \brief The module file is out-of-date.
    157     OutOfDate
    158   };
    159 
    160   /// \brief Attempts to create a new module and add it to the list of known
    161   /// modules.
    162   ///
    163   /// \param FileName The file name of the module to be loaded.
    164   ///
    165   /// \param Type The kind of module being loaded.
    166   ///
    167   /// \param ImportLoc The location at which the module is imported.
    168   ///
    169   /// \param ImportedBy The module that is importing this module, or NULL if
    170   /// this module is imported directly by the user.
    171   ///
    172   /// \param Generation The generation in which this module was loaded.
    173   ///
    174   /// \param ExpectedSize The expected size of the module file, used for
    175   /// validation. This will be zero if unknown.
    176   ///
    177   /// \param ExpectedModTime The expected modification time of the module
    178   /// file, used for validation. This will be zero if unknown.
    179   ///
    180   /// \param Module A pointer to the module file if the module was successfully
    181   /// loaded.
    182   ///
    183   /// \param ErrorStr Will be set to a non-empty string if any errors occurred
    184   /// while trying to load the module.
    185   ///
    186   /// \return A pointer to the module that corresponds to this file name,
    187   /// and a value indicating whether the module was loaded.
    188   AddModuleResult addModule(StringRef FileName, ModuleKind Type,
    189                             SourceLocation ImportLoc,
    190                             ModuleFile *ImportedBy, unsigned Generation,
    191                             off_t ExpectedSize, time_t ExpectedModTime,
    192                             ModuleFile *&Module,
    193                             std::string &ErrorStr);
    194 
    195   /// \brief Remove the given set of modules.
    196   void removeModules(ModuleIterator first, ModuleIterator last,
    197                      ModuleMap *modMap);
    198 
    199   /// \brief Add an in-memory buffer the list of known buffers
    200   void addInMemoryBuffer(StringRef FileName, llvm::MemoryBuffer *Buffer);
    201 
    202   /// \brief Set the global module index.
    203   void setGlobalIndex(GlobalModuleIndex *Index);
    204 
    205   /// \brief Notification from the AST reader that the given module file
    206   /// has been "accepted", and will not (can not) be unloaded.
    207   void moduleFileAccepted(ModuleFile *MF);
    208 
    209   /// \brief Visit each of the modules.
    210   ///
    211   /// This routine visits each of the modules, starting with the
    212   /// "root" modules that no other loaded modules depend on, and
    213   /// proceeding to the leaf modules, visiting each module only once
    214   /// during the traversal.
    215   ///
    216   /// This traversal is intended to support various "lookup"
    217   /// operations that can find data in any of the loaded modules.
    218   ///
    219   /// \param Visitor A visitor function that will be invoked with each
    220   /// module and the given user data pointer. The return value must be
    221   /// convertible to bool; when false, the visitation continues to
    222   /// modules that the current module depends on. When true, the
    223   /// visitation skips any modules that the current module depends on.
    224   ///
    225   /// \param UserData User data associated with the visitor object, which
    226   /// will be passed along to the visitor.
    227   ///
    228   /// \param ModuleFilesHit If non-NULL, contains the set of module files
    229   /// that we know we need to visit because the global module index told us to.
    230   /// Any module that is known to both the global module index and the module
    231   /// manager that is *not* in this set can be skipped.
    232   void visit(bool (*Visitor)(ModuleFile &M, void *UserData), void *UserData,
    233              llvm::SmallPtrSet<ModuleFile *, 4> *ModuleFilesHit = 0);
    234 
    235   /// \brief Visit each of the modules with a depth-first traversal.
    236   ///
    237   /// This routine visits each of the modules known to the module
    238   /// manager using a depth-first search, starting with the first
    239   /// loaded module. The traversal invokes the callback both before
    240   /// traversing the children (preorder traversal) and after
    241   /// traversing the children (postorder traversal).
    242   ///
    243   /// \param Visitor A visitor function that will be invoked with each
    244   /// module and given a \c Preorder flag that indicates whether we're
    245   /// visiting the module before or after visiting its children.  The
    246   /// visitor may return true at any time to abort the depth-first
    247   /// visitation.
    248   ///
    249   /// \param UserData User data ssociated with the visitor object,
    250   /// which will be passed along to the user.
    251   void visitDepthFirst(bool (*Visitor)(ModuleFile &M, bool Preorder,
    252                                        void *UserData),
    253                        void *UserData);
    254 
    255   /// \brief Attempt to resolve the given module file name to a file entry.
    256   ///
    257   /// \param FileName The name of the module file.
    258   ///
    259   /// \param ExpectedSize The size that the module file is expected to have.
    260   /// If the actual size differs, the resolver should return \c true.
    261   ///
    262   /// \param ExpectedModTime The modification time that the module file is
    263   /// expected to have. If the actual modification time differs, the resolver
    264   /// should return \c true.
    265   ///
    266   /// \param File Will be set to the file if there is one, or null
    267   /// otherwise.
    268   ///
    269   /// \returns True if a file exists but does not meet the size/
    270   /// modification time criteria, false if the file is either available and
    271   /// suitable, or is missing.
    272   bool lookupModuleFile(StringRef FileName,
    273                         off_t ExpectedSize,
    274                         time_t ExpectedModTime,
    275                         const FileEntry *&File);
    276 
    277   /// \brief View the graphviz representation of the module graph.
    278   void viewGraph();
    279 };
    280 
    281 } } // end namespace clang::serialization
    282 
    283 #endif
    284