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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
55 operator Module *() const { return Storage.getPointer(); }
56
57 /// Determines whether this is a normal return, whether or not loading the
58 /// module was successful.
59 bool isNormal() const { return Storage.getInt() == Normal; }
60
61 /// Determines whether the module, which failed to load, was
62 /// actually a submodule that we expected to see (based on implying the
63 /// submodule from header structure), but didn't materialize in the actual
64 /// module.
65 bool isMissingExpected() const { return Storage.getInt() == MissingExpected; }
66
67 /// Determines whether the module failed to load due to a configuration
68 /// mismatch with an explicitly-named .pcm file from the command line.
69 bool isConfigMismatch() const { return Storage.getInt() == ConfigMismatch; }
70};
71
72/// Abstract interface for a module loader.
73///
74/// This abstract interface describes a module loader, which is responsible
75/// for resolving a module name (e.g., "std") to an actual module file, and
76/// then loading that module.
77class ModuleLoader {
78 // Building a module if true.
79 bool BuildingModule;
80
81public:
82 explicit ModuleLoader(bool BuildingModule = false)
83 : BuildingModule(BuildingModule) {}
84
85 virtual ~ModuleLoader();
86
87 /// Returns true if this instance is building a module.
88 bool buildingModule() const {
89 return BuildingModule;
90 }
91
92 /// Flag indicating whether this instance is building a module.
93 void setBuildingModule(bool BuildingModuleFlag) {
94 BuildingModule = BuildingModuleFlag;
95 }
96
97 /// Attempt to load the given module.
98 ///
99 /// This routine attempts to load the module described by the given
100 /// parameters. If there is a module cache, this may implicitly compile the
101 /// module before loading it.
102 ///
103 /// \param ImportLoc The location of the 'import' keyword.
104 ///
105 /// \param Path The identifiers (and their locations) of the module
106 /// "path", e.g., "std.vector" would be split into "std" and "vector".
107 ///
108 /// \param Visibility The visibility provided for the names in the loaded
109 /// module.
110 ///
111 /// \param IsInclusionDirective Indicates that this module is being loaded
112 /// implicitly, due to the presence of an inclusion directive. Otherwise,
113 /// it is being loaded due to an import declaration.
114 ///
115 /// \returns If successful, returns the loaded module. Otherwise, returns
116 /// NULL to indicate that the module could not be loaded.
117 virtual ModuleLoadResult loadModule(SourceLocation ImportLoc,
118 ModuleIdPath Path,
119 Module::NameVisibilityKind Visibility,
120 bool IsInclusionDirective) = 0;
121
122 /// Attempt to create the given module from the specified source buffer.
123 /// Does not load the module or make any submodule visible; for that, use
124 /// loadModule and makeModuleVisible.
125 ///
126 /// \param Loc The location at which to create the module.
127 /// \param ModuleName The name of the module to create.
128 /// \param Source The source of the module: a (preprocessed) module map.
129 virtual void createModuleFromSource(SourceLocation Loc, StringRef ModuleName,
130 StringRef Source) = 0;
131
132 /// Make the given module visible.
133 virtual void makeModuleVisible(Module *Mod,
134 Module::NameVisibilityKind Visibility,
135 SourceLocation ImportLoc) = 0;
136
137 /// Load, create, or return global module.
138 /// This function returns an existing global module index, if one
139 /// had already been loaded or created, or loads one if it
140 /// exists, or creates one if it doesn't exist.
141 /// Also, importantly, if the index doesn't cover all the modules
142 /// in the module map, it will be update to do so here, because
143 /// of its use in searching for needed module imports and
144 /// associated fixit messages.
145 /// \param TriggerLoc The location for what triggered the load.
146 /// \returns Returns null if load failed.
147 virtual GlobalModuleIndex *loadGlobalModuleIndex(
148 SourceLocation TriggerLoc) = 0;
149
150 /// Check global module index for missing imports.
151 /// \param Name The symbol name to look for.
152 /// \param TriggerLoc The location for what triggered the load.
153 /// \returns Returns true if any modules with that symbol found.
154 virtual bool lookupMissingImports(StringRef Name,
155 SourceLocation TriggerLoc) = 0;
156
157 bool HadFatalFailure = false;
158};
159
160/// A module loader that doesn't know how to create or load modules.
161class TrivialModuleLoader : public ModuleLoader {
162public:
163 ModuleLoadResult loadModule(SourceLocation ImportLoc, ModuleIdPath Path,
164 Module::NameVisibilityKind Visibility,
165 bool IsInclusionDirective) override {
166 return {};
167 }
168
169 void createModuleFromSource(SourceLocation ImportLoc, StringRef ModuleName,
170 StringRef Source) override {}
171
172 void makeModuleVisible(Module *Mod, Module::NameVisibilityKind Visibility,
173 SourceLocation ImportLoc) override {}
174
175 GlobalModuleIndex *loadGlobalModuleIndex(SourceLocation TriggerLoc) override {
176 return nullptr;
177 }
178
179 bool lookupMissingImports(StringRef Name,
180 SourceLocation TriggerLoc) override {
181 return false;
182 }
183};
184
185} // namespace clang
186
187#endif // LLVM_CLANG_LEX_MODULELOADER_H
188

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