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