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
22namespace clang {
23
24class GlobalModuleIndex;
25class IdentifierInfo;
26class Module;
27
28/// \brief A sequence of identifier/location pairs used to describe a particular
29/// module or submodule, e.g., std.vector.
30typedef ArrayRef<std::pair<IdentifierInfo *, SourceLocation> > ModuleIdPath;
31
32/// \brief Describes the result of attempting to load a module.
33class ModuleLoadResult {
34public:
35  enum LoadResultKind {
36    // We either succeeded or failed to load the named module.
37    Normal,
38    // The module exists, but does not actually contain the named submodule.
39    // This should only happen if the named submodule was inferred from an
40    // umbrella directory, but not actually part of the umbrella header.
41    MissingExpected,
42    // The module exists but cannot be imported due to a configuration mismatch.
43    ConfigMismatch
44  };
45  llvm::PointerIntPair<Module *, 2, LoadResultKind> Storage;
46
47  ModuleLoadResult() : Storage() { }
48  ModuleLoadResult(Module *M) : Storage(M, Normal) {}
49  ModuleLoadResult(LoadResultKind Kind) : Storage(nullptr, Kind) {}
50
51  operator Module *() const { return Storage.getPointer(); }
52
53  /// \brief Determines whether the module, which failed to load, was
54  /// actually a submodule that we expected to see (based on implying the
55  /// submodule from header structure), but didn't materialize in the actual
56  /// module.
57  bool isMissingExpected() const { return Storage.getInt() == MissingExpected; }
58
59  /// \brief Determines whether the module failed to load due to a configuration
60  /// mismatch with an explicitly-named .pcm file from the command line.
61  bool isConfigMismatch() const { return Storage.getInt() == ConfigMismatch; }
62};
63
64/// \brief Abstract interface for a module loader.
65///
66/// This abstract interface describes a module loader, which is responsible
67/// for resolving a module name (e.g., "std") to an actual module file, and
68/// then loading that module.
69class ModuleLoader {
70  // Building a module if true.
71  bool BuildingModule;
72public:
73  explicit ModuleLoader(bool BuildingModule = false) :
74    BuildingModule(BuildingModule),
75    HadFatalFailure(false) {}
76
77  virtual ~ModuleLoader();
78
79  /// \brief Returns true if this instance is building a module.
80  bool buildingModule() const {
81    return BuildingModule;
82  }
83  /// \brief Flag indicating whether this instance is building a module.
84  void setBuildingModule(bool BuildingModuleFlag) {
85    BuildingModule = BuildingModuleFlag;
86  }
87
88  /// \brief Attempt to load the given module.
89  ///
90  /// This routine attempts to load the module described by the given
91  /// parameters.
92  ///
93  /// \param ImportLoc The location of the 'import' keyword.
94  ///
95  /// \param Path The identifiers (and their locations) of the module
96  /// "path", e.g., "std.vector" would be split into "std" and "vector".
97  ///
98  /// \param Visibility The visibility provided for the names in the loaded
99  /// module.
100  ///
101  /// \param IsInclusionDirective Indicates that this module is being loaded
102  /// implicitly, due to the presence of an inclusion directive. Otherwise,
103  /// it is being loaded due to an import declaration.
104  ///
105  /// \returns If successful, returns the loaded module. Otherwise, returns
106  /// NULL to indicate that the module could not be loaded.
107  virtual ModuleLoadResult loadModule(SourceLocation ImportLoc,
108                                      ModuleIdPath Path,
109                                      Module::NameVisibilityKind Visibility,
110                                      bool IsInclusionDirective) = 0;
111
112  /// Attempt to load the given module from the specified source buffer. Does
113  /// not make any submodule visible; for that, use loadModule or
114  /// makeModuleVisible.
115  ///
116  /// \param Loc The location at which the module was loaded.
117  /// \param ModuleName The name of the module to build.
118  /// \param Source The source of the module: a (preprocessed) module map.
119  virtual void loadModuleFromSource(SourceLocation Loc, StringRef ModuleName,
120                                    StringRef Source) = 0;
121
122  /// \brief Make the given module visible.
123  virtual void makeModuleVisible(Module *Mod,
124                                 Module::NameVisibilityKind Visibility,
125                                 SourceLocation ImportLoc) = 0;
126
127  /// \brief Load, create, or return global module.
128  /// This function returns an existing global module index, if one
129  /// had already been loaded or created, or loads one if it
130  /// exists, or creates one if it doesn't exist.
131  /// Also, importantly, if the index doesn't cover all the modules
132  /// in the module map, it will be update to do so here, because
133  /// of its use in searching for needed module imports and
134  /// associated fixit messages.
135  /// \param TriggerLoc The location for what triggered the load.
136  /// \returns Returns null if load failed.
137  virtual GlobalModuleIndex *loadGlobalModuleIndex(
138                                                SourceLocation TriggerLoc) = 0;
139
140  /// Check global module index for missing imports.
141  /// \param Name The symbol name to look for.
142  /// \param TriggerLoc The location for what triggered the load.
143  /// \returns Returns true if any modules with that symbol found.
144  virtual bool lookupMissingImports(StringRef Name,
145                                    SourceLocation TriggerLoc) = 0;
146
147  bool HadFatalFailure;
148};
149
150/// A module loader that doesn't know how to load modules.
151class TrivialModuleLoader : public ModuleLoader {
152public:
153  ModuleLoadResult loadModule(SourceLocation ImportLoc, ModuleIdPath Path,
154                              Module::NameVisibilityKind Visibility,
155                              bool IsInclusionDirective) override {
156    return ModuleLoadResult();
157  }
158
159  void loadModuleFromSource(SourceLocation ImportLoc, StringRef ModuleName,
160                            StringRef Source) override {}
161
162  void makeModuleVisible(Module *Mod, Module::NameVisibilityKind Visibility,
163                         SourceLocation ImportLoc) override {}
164
165  GlobalModuleIndex *loadGlobalModuleIndex(SourceLocation TriggerLoc) override {
166    return nullptr;
167  }
168  bool lookupMissingImports(StringRef Name,
169                            SourceLocation TriggerLoc) override {
170    return 0;
171  }
172};
173
174}
175
176#endif
177