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1 //===--- ModuleLoader.h - Module Loader Interface ---------------*- 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 ModuleLoader interface, which is responsible for
11 //  loading named modules.
12 //
13 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_CLANG_LEX_MODULELOADER_H
15 #define LLVM_CLANG_LEX_MODULELOADER_H
16 
17 #include "clang/Basic/Module.h"
18 #include "clang/Basic/SourceLocation.h"
19 #include "llvm/ADT/ArrayRef.h"
20 #include "llvm/ADT/PointerIntPair.h"
21 
22 namespace clang {
23 
24 class GlobalModuleIndex;
25 class IdentifierInfo;
26 class Module;
27 
28 /// \brief A sequence of identifier/location pairs used to describe a particular
29 /// module or submodule, e.g., std.vector.
30 typedef ArrayRef<std::pair<IdentifierInfo *, SourceLocation> > ModuleIdPath;
31 
32 /// \brief Describes the result of attempting to load a module.
33 class ModuleLoadResult {
34   llvm::PointerIntPair<Module *, 1, bool> Storage;
35 
36 public:
ModuleLoadResult()37   ModuleLoadResult() : Storage() { }
38 
ModuleLoadResult(Module * module,bool missingExpected)39   ModuleLoadResult(Module *module, bool missingExpected)
40     : Storage(module, missingExpected) { }
41 
42   operator Module *() const { return Storage.getPointer(); }
43 
44   /// \brief Determines whether the module, which failed to load, was
45   /// actually a submodule that we expected to see (based on implying the
46   /// submodule from header structure), but didn't materialize in the actual
47   /// module.
isMissingExpected()48   bool isMissingExpected() const { return Storage.getInt(); }
49 };
50 
51 /// \brief Abstract interface for a module loader.
52 ///
53 /// This abstract interface describes a module loader, which is responsible
54 /// for resolving a module name (e.g., "std") to an actual module file, and
55 /// then loading that module.
56 class ModuleLoader {
57   // Building a module if true.
58   bool BuildingModule;
59 public:
60   explicit ModuleLoader(bool BuildingModule = false) :
BuildingModule(BuildingModule)61     BuildingModule(BuildingModule),
62     HadFatalFailure(false) {}
63 
64   virtual ~ModuleLoader();
65 
66   /// \brief Returns true if this instance is building a module.
buildingModule()67   bool buildingModule() const {
68     return BuildingModule;
69   }
70   /// \brief Flag indicating whether this instance is building a module.
setBuildingModule(bool BuildingModuleFlag)71   void setBuildingModule(bool BuildingModuleFlag) {
72     BuildingModule = BuildingModuleFlag;
73   }
74 
75   /// \brief Attempt to load the given module.
76   ///
77   /// This routine attempts to load the module described by the given
78   /// parameters.
79   ///
80   /// \param ImportLoc The location of the 'import' keyword.
81   ///
82   /// \param Path The identifiers (and their locations) of the module
83   /// "path", e.g., "std.vector" would be split into "std" and "vector".
84   ///
85   /// \param Visibility The visibility provided for the names in the loaded
86   /// module.
87   ///
88   /// \param IsInclusionDirective Indicates that this module is being loaded
89   /// implicitly, due to the presence of an inclusion directive. Otherwise,
90   /// it is being loaded due to an import declaration.
91   ///
92   /// \returns If successful, returns the loaded module. Otherwise, returns
93   /// NULL to indicate that the module could not be loaded.
94   virtual ModuleLoadResult loadModule(SourceLocation ImportLoc,
95                                       ModuleIdPath Path,
96                                       Module::NameVisibilityKind Visibility,
97                                       bool IsInclusionDirective) = 0;
98 
99   /// \brief Make the given module visible.
100   virtual void makeModuleVisible(Module *Mod,
101                                  Module::NameVisibilityKind Visibility,
102                                  SourceLocation ImportLoc) = 0;
103 
104   /// \brief Load, create, or return global module.
105   /// This function returns an existing global module index, if one
106   /// had already been loaded or created, or loads one if it
107   /// exists, or creates one if it doesn't exist.
108   /// Also, importantly, if the index doesn't cover all the modules
109   /// in the module map, it will be update to do so here, because
110   /// of its use in searching for needed module imports and
111   /// associated fixit messages.
112   /// \param TriggerLoc The location for what triggered the load.
113   /// \returns Returns null if load failed.
114   virtual GlobalModuleIndex *loadGlobalModuleIndex(
115                                                 SourceLocation TriggerLoc) = 0;
116 
117   /// Check global module index for missing imports.
118   /// \param Name The symbol name to look for.
119   /// \param TriggerLoc The location for what triggered the load.
120   /// \returns Returns true if any modules with that symbol found.
121   virtual bool lookupMissingImports(StringRef Name,
122                                     SourceLocation TriggerLoc) = 0;
123 
124   bool HadFatalFailure;
125 };
126 
127 }
128 
129 #endif
130