1//===- ModuleLoader.h - Module Loader Interface -----------------*- 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// This file defines the ModuleLoader interface, which is responsible for
10// loading named modules.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_CLANG_LEX_MODULELOADER_H
15#define LLVM_CLANG_LEX_MODULELOADER_H
16
17#include "clang/Basic/LLVM.h"
18#include "clang/Basic/Module.h"
19#include "clang/Basic/SourceLocation.h"
20#include "llvm/ADT/ArrayRef.h"
21#include "llvm/ADT/PointerIntPair.h"
22#include "llvm/ADT/StringRef.h"
23#include <utility>
24
25namespace clang {
26
27class GlobalModuleIndex;
28class IdentifierInfo;
29
30/// A sequence of identifier/location pairs used to describe a particular
31/// module or submodule, e.g., std.vector.
32using ModuleIdPath = ArrayRef<std::pair<IdentifierInfo *, SourceLocation>>;
33
34/// Describes the result of attempting to load a module.
35class ModuleLoadResult {
36public:
37 enum LoadResultKind {
38 // We either succeeded or failed to load the named module.
39 Normal,
40
41 // The module exists, but does not actually contain the named submodule.
42 // This should only happen if the named submodule was inferred from an
43 // umbrella directory, but not actually part of the umbrella header.
44 MissingExpected,
45
46 // The module exists but cannot be imported due to a configuration mismatch.
47 ConfigMismatch,
48 };
49 llvm::PointerIntPair<Module *, 2, LoadResultKind> Storage;
50
51 ModuleLoadResult() = default;
52 ModuleLoadResult(Module *M) : Storage(M, Normal) {}
53 ModuleLoadResult(LoadResultKind Kind) : Storage(nullptr, Kind) {}
54 ModuleLoadResult(Module *M, LoadResultKind Kind) : Storage(M, Kind) {}
55
56 operator bool() const {
57 return Storage.getInt() == Normal && Storage.getPointer();
58 }
59
60 operator Module *() const { return Storage.getPointer(); }
61
62 /// Determines whether this is a normal return, whether or not loading the
63 /// module was successful.
64 bool isNormal() const { return Storage.getInt() == Normal; }
65
66 /// Determines whether the module, which failed to load, was
67 /// actually a submodule that we expected to see (based on implying the
68 /// submodule from header structure), but didn't materialize in the actual
69 /// module.
70 bool isMissingExpected() const { return Storage.getInt() == MissingExpected; }
71
72 /// Determines whether the module failed to load due to a configuration
73 /// mismatch with an explicitly-named .pcm file from the command line.
74 bool isConfigMismatch() const { return Storage.getInt() == ConfigMismatch; }
75};
76
77/// Abstract interface for a module loader.
78///
79/// This abstract interface describes a module loader, which is responsible
80/// for resolving a module name (e.g., "std") to an actual module file, and
81/// then loading that module.
82class ModuleLoader {
83 // Building a module if true.
84 bool BuildingModule;
85
86public:
87 explicit ModuleLoader(bool BuildingModule = false)
88 : BuildingModule(BuildingModule) {}
89
90 virtual ~ModuleLoader();
91
92 /// Returns true if this instance is building a module.
93 bool buildingModule() const {
94 return BuildingModule;
95 }
96
97 /// Flag indicating whether this instance is building a module.
98 void setBuildingModule(bool BuildingModuleFlag) {
99 BuildingModule = BuildingModuleFlag;
100 }
101
102 /// Attempt to load the given module.
103 ///
104 /// This routine attempts to load the module described by the given
105 /// parameters. If there is a module cache, this may implicitly compile the
106 /// module before loading it.
107 ///
108 /// \param ImportLoc The location of the 'import' keyword.
109 ///
110 /// \param Path The identifiers (and their locations) of the module
111 /// "path", e.g., "std.vector" would be split into "std" and "vector".
112 ///
113 /// \param Visibility The visibility provided for the names in the loaded
114 /// module.
115 ///
116 /// \param IsInclusionDirective Indicates that this module is being loaded
117 /// implicitly, due to the presence of an inclusion directive. Otherwise,
118 /// it is being loaded due to an import declaration.
119 ///
120 /// \returns If successful, returns the loaded module. Otherwise, returns
121 /// NULL to indicate that the module could not be loaded.
122 virtual ModuleLoadResult loadModule(SourceLocation ImportLoc,
123 ModuleIdPath Path,
124 Module::NameVisibilityKind Visibility,
125 bool IsInclusionDirective) = 0;
126
127 /// Attempt to create the given module from the specified source buffer.
128 /// Does not load the module or make any submodule visible; for that, use
129 /// loadModule and makeModuleVisible.
130 ///
131 /// \param Loc The location at which to create the module.
132 /// \param ModuleName The name of the module to create.
133 /// \param Source The source of the module: a (preprocessed) module map.
134 virtual void createModuleFromSource(SourceLocation Loc, StringRef ModuleName,
135 StringRef Source) = 0;
136
137 /// Make the given module visible.
138 virtual void makeModuleVisible(Module *Mod,
139 Module::NameVisibilityKind Visibility,
140 SourceLocation ImportLoc) = 0;
141
142 /// Load, create, or return global module.
143 /// This function returns an existing global module index, if one
144 /// had already been loaded or created, or loads one if it
145 /// exists, or creates one if it doesn't exist.
146 /// Also, importantly, if the index doesn't cover all the modules
147 /// in the module map, it will be update to do so here, because
148 /// of its use in searching for needed module imports and
149 /// associated fixit messages.
150 /// \param TriggerLoc The location for what triggered the load.
151 /// \returns Returns null if load failed.
152 virtual GlobalModuleIndex *loadGlobalModuleIndex(
153 SourceLocation TriggerLoc) = 0;
154
155 /// Check global module index for missing imports.
156 /// \param Name The symbol name to look for.
157 /// \param TriggerLoc The location for what triggered the load.
158 /// \returns Returns true if any modules with that symbol found.
159 virtual bool lookupMissingImports(StringRef Name,
160 SourceLocation TriggerLoc) = 0;
161
162 bool HadFatalFailure = false;
163};
164
165/// A module loader that doesn't know how to create or load modules.
166class TrivialModuleLoader : public ModuleLoader {
167public:
168 ModuleLoadResult loadModule(SourceLocation ImportLoc, ModuleIdPath Path,
169 Module::NameVisibilityKind Visibility,
170 bool IsInclusionDirective) override {
171 return {};
172 }
173
174 void createModuleFromSource(SourceLocation ImportLoc, StringRef ModuleName,
175 StringRef Source) override {}
176
177 void makeModuleVisible(Module *Mod, Module::NameVisibilityKind Visibility,
178 SourceLocation ImportLoc) override {}
179
180 GlobalModuleIndex *loadGlobalModuleIndex(SourceLocation TriggerLoc) override {
181 return nullptr;
182 }
183
184 bool lookupMissingImports(StringRef Name,
185 SourceLocation TriggerLoc) override {
186 return false;
187 }
188};
189
190} // namespace clang
191
192#endif // LLVM_CLANG_LEX_MODULELOADER_H
193

source code of clang/include/clang/Lex/ModuleLoader.h