1//===-- FrontendAction.h - Generic Frontend Action 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/// \file
10/// Defines the clang::FrontendAction interface and various convenience
11/// abstract classes (clang::ASTFrontendAction, clang::PluginASTAction,
12/// clang::PreprocessorFrontendAction, and clang::WrapperFrontendAction)
13/// derived from it.
14///
15//===----------------------------------------------------------------------===//
16
17#ifndef LLVM_CLANG_FRONTEND_FRONTENDACTION_H
18#define LLVM_CLANG_FRONTEND_FRONTENDACTION_H
19
20#include "clang/AST/ASTConsumer.h"
21#include "clang/Basic/LLVM.h"
22#include "clang/Basic/LangOptions.h"
23#include "clang/Frontend/CompilerInstance.h"
24#include "clang/Frontend/FrontendOptions.h"
25#include "llvm/ADT/StringRef.h"
26#include "llvm/Support/Error.h"
27#include <memory>
28#include <string>
29#include <vector>
30
31namespace clang {
32class ASTMergeAction;
33class ASTUnit;
34class CompilerInstance;
35
36/// Abstract base class for actions which can be performed by the frontend.
37class FrontendAction {
38 FrontendInputFile CurrentInput;
39 std::unique_ptr<ASTUnit> CurrentASTUnit;
40 CompilerInstance *Instance;
41 friend class ASTMergeAction;
42 friend class WrapperFrontendAction;
43
44private:
45 std::unique_ptr<ASTConsumer> CreateWrappedASTConsumer(CompilerInstance &CI,
46 StringRef InFile);
47
48protected:
49 /// @name Implementation Action Interface
50 /// @{
51
52 /// Prepare to execute the action on the given CompilerInstance.
53 ///
54 /// This is called before executing the action on any inputs, and can modify
55 /// the configuration as needed (including adjusting the input list).
56 virtual bool PrepareToExecuteAction(CompilerInstance &CI) { return true; }
57
58 /// Create the AST consumer object for this action, if supported.
59 ///
60 /// This routine is called as part of BeginSourceFile(), which will
61 /// fail if the AST consumer cannot be created. This will not be called if the
62 /// action has indicated that it only uses the preprocessor.
63 ///
64 /// \param CI - The current compiler instance, provided as a convenience, see
65 /// getCompilerInstance().
66 ///
67 /// \param InFile - The current input file, provided as a convenience, see
68 /// getCurrentFile().
69 ///
70 /// \return The new AST consumer, or null on failure.
71 virtual std::unique_ptr<ASTConsumer> CreateASTConsumer(CompilerInstance &CI,
72 StringRef InFile) = 0;
73
74 /// Callback before starting processing a single input, giving the
75 /// opportunity to modify the CompilerInvocation or do some other action
76 /// before BeginSourceFileAction is called.
77 ///
78 /// \return True on success; on failure BeginSourceFileAction(),
79 /// ExecuteAction() and EndSourceFileAction() will not be called.
80 virtual bool BeginInvocation(CompilerInstance &CI) { return true; }
81
82 /// Callback at the start of processing a single input.
83 ///
84 /// \return True on success; on failure ExecutionAction() and
85 /// EndSourceFileAction() will not be called.
86 virtual bool BeginSourceFileAction(CompilerInstance &CI);
87
88 /// Callback to run the program action, using the initialized
89 /// compiler instance.
90 ///
91 /// This is guaranteed to only be called between BeginSourceFileAction()
92 /// and EndSourceFileAction().
93 virtual void ExecuteAction() = 0;
94
95 /// Callback at the end of processing a single input.
96 ///
97 /// This is guaranteed to only be called following a successful call to
98 /// BeginSourceFileAction (and BeginSourceFile).
99 virtual void EndSourceFileAction();
100
101 /// Callback at the end of processing a single input, to determine
102 /// if the output files should be erased or not.
103 ///
104 /// By default it returns true if a compiler error occurred.
105 /// This is guaranteed to only be called following a successful call to
106 /// BeginSourceFileAction (and BeginSourceFile).
107 virtual bool shouldEraseOutputFiles();
108
109 /// @}
110
111public:
112 FrontendAction();
113 virtual ~FrontendAction();
114
115 /// @name Compiler Instance Access
116 /// @{
117
118 CompilerInstance &getCompilerInstance() const {
119 assert(Instance && "Compiler instance not registered!");
120 return *Instance;
121 }
122
123 void setCompilerInstance(CompilerInstance *Value) { Instance = Value; }
124
125 /// @}
126 /// @name Current File Information
127 /// @{
128
129 bool isCurrentFileAST() const {
130 assert(!CurrentInput.isEmpty() && "No current file!");
131 return (bool)CurrentASTUnit;
132 }
133
134 const FrontendInputFile &getCurrentInput() const {
135 return CurrentInput;
136 }
137
138 StringRef getCurrentFile() const {
139 assert(!CurrentInput.isEmpty() && "No current file!");
140 return CurrentInput.getFile();
141 }
142
143 StringRef getCurrentFileOrBufferName() const {
144 assert(!CurrentInput.isEmpty() && "No current file!");
145 return CurrentInput.isFile()
146 ? CurrentInput.getFile()
147 : CurrentInput.getBuffer().getBufferIdentifier();
148 }
149
150 InputKind getCurrentFileKind() const {
151 assert(!CurrentInput.isEmpty() && "No current file!");
152 return CurrentInput.getKind();
153 }
154
155 ASTUnit &getCurrentASTUnit() const {
156 assert(CurrentASTUnit && "No current AST unit!");
157 return *CurrentASTUnit;
158 }
159
160 Module *getCurrentModule() const;
161
162 std::unique_ptr<ASTUnit> takeCurrentASTUnit();
163
164 void setCurrentInput(const FrontendInputFile &CurrentInput,
165 std::unique_ptr<ASTUnit> AST = nullptr);
166
167 /// @}
168 /// @name Supported Modes
169 /// @{
170
171 /// Is this action invoked on a model file?
172 ///
173 /// Model files are incomplete translation units that relies on type
174 /// information from another translation unit. Check ParseModelFileAction for
175 /// details.
176 virtual bool isModelParsingAction() const { return false; }
177
178 /// Does this action only use the preprocessor?
179 ///
180 /// If so no AST context will be created and this action will be invalid
181 /// with AST file inputs.
182 virtual bool usesPreprocessorOnly() const = 0;
183
184 /// For AST-based actions, the kind of translation unit we're handling.
185 virtual TranslationUnitKind getTranslationUnitKind();
186
187 /// Does this action support use with PCH?
188 virtual bool hasPCHSupport() const { return true; }
189
190 /// Does this action support use with AST files?
191 virtual bool hasASTFileSupport() const { return true; }
192
193 /// Does this action support use with IR files?
194 virtual bool hasIRSupport() const { return false; }
195
196 /// Does this action support use with CIR files?
197 virtual bool hasCIRSupport() const { return false; }
198
199 /// Does this action support use with code completion?
200 virtual bool hasCodeCompletionSupport() const { return false; }
201
202 /// @}
203 /// @name Public Action Interface
204 /// @{
205
206 /// Prepare the action to execute on the given compiler instance.
207 bool PrepareToExecute(CompilerInstance &CI) {
208 return PrepareToExecuteAction(CI);
209 }
210
211 /// Prepare the action for processing the input file \p Input.
212 ///
213 /// This is run after the options and frontend have been initialized,
214 /// but prior to executing any per-file processing.
215 ///
216 /// \param CI - The compiler instance this action is being run from. The
217 /// action may store and use this object up until the matching EndSourceFile
218 /// action.
219 ///
220 /// \param Input - The input filename and kind. Some input kinds are handled
221 /// specially, for example AST inputs, since the AST file itself contains
222 /// several objects which would normally be owned by the
223 /// CompilerInstance. When processing AST input files, these objects should
224 /// generally not be initialized in the CompilerInstance -- they will
225 /// automatically be shared with the AST file in between
226 /// BeginSourceFile() and EndSourceFile().
227 ///
228 /// \return True on success; on failure the compilation of this file should
229 /// be aborted and neither Execute() nor EndSourceFile() should be called.
230 bool BeginSourceFile(CompilerInstance &CI, const FrontendInputFile &Input);
231
232 /// Set the source manager's main input file, and run the action.
233 llvm::Error Execute();
234
235 /// Perform any per-file post processing, deallocate per-file
236 /// objects, and run statistics and output file cleanup code.
237 virtual void EndSourceFile();
238
239 /// @}
240};
241
242/// Abstract base class to use for AST consumer-based frontend actions.
243class ASTFrontendAction : public FrontendAction {
244protected:
245 /// Implement the ExecuteAction interface by running Sema on
246 /// the already-initialized AST consumer.
247 ///
248 /// This will also take care of instantiating a code completion consumer if
249 /// the user requested it and the action supports it.
250 void ExecuteAction() override;
251
252public:
253 ASTFrontendAction() {}
254 bool usesPreprocessorOnly() const override { return false; }
255};
256
257class PluginASTAction : public ASTFrontendAction {
258 virtual void anchor();
259public:
260 std::unique_ptr<ASTConsumer> CreateASTConsumer(CompilerInstance &CI,
261 StringRef InFile) override = 0;
262
263 /// Parse the given plugin command line arguments.
264 ///
265 /// \param CI - The compiler instance, for use in reporting diagnostics.
266 /// \return True if the parsing succeeded; otherwise the plugin will be
267 /// destroyed and no action run. The plugin is responsible for using the
268 /// CompilerInstance's Diagnostic object to report errors.
269 virtual bool ParseArgs(const CompilerInstance &CI,
270 const std::vector<std::string> &arg) = 0;
271
272 enum ActionType {
273 CmdlineBeforeMainAction, ///< Execute the action before the main action if
274 ///< on the command line
275 CmdlineAfterMainAction, ///< Execute the action after the main action if on
276 ///< the command line
277 ReplaceAction, ///< Replace the main action
278 AddBeforeMainAction, ///< Execute the action before the main action
279 AddAfterMainAction ///< Execute the action after the main action
280 };
281 /// Get the action type for this plugin
282 ///
283 /// \return The action type. By default we use CmdlineAfterMainAction.
284 virtual ActionType getActionType() { return CmdlineAfterMainAction; }
285};
286
287/// Abstract base class to use for preprocessor-based frontend actions.
288class PreprocessorFrontendAction : public FrontendAction {
289protected:
290 /// Provide a default implementation which returns aborts;
291 /// this method should never be called by FrontendAction clients.
292 std::unique_ptr<ASTConsumer> CreateASTConsumer(CompilerInstance &CI,
293 StringRef InFile) override;
294
295public:
296 bool usesPreprocessorOnly() const override { return true; }
297};
298
299/// A frontend action which simply wraps some other runtime-specified
300/// frontend action.
301///
302/// Deriving from this class allows an action to inject custom logic around
303/// some existing action's behavior. It implements every virtual method in
304/// the FrontendAction interface by forwarding to the wrapped action.
305class WrapperFrontendAction : public FrontendAction {
306protected:
307 std::unique_ptr<FrontendAction> WrappedAction;
308
309 bool PrepareToExecuteAction(CompilerInstance &CI) override;
310 std::unique_ptr<ASTConsumer> CreateASTConsumer(CompilerInstance &CI,
311 StringRef InFile) override;
312 bool BeginInvocation(CompilerInstance &CI) override;
313 bool BeginSourceFileAction(CompilerInstance &CI) override;
314 void ExecuteAction() override;
315 void EndSourceFile() override;
316 void EndSourceFileAction() override;
317 bool shouldEraseOutputFiles() override;
318
319public:
320 /// Construct a WrapperFrontendAction from an existing action, taking
321 /// ownership of it.
322 WrapperFrontendAction(std::unique_ptr<FrontendAction> WrappedAction);
323
324 bool usesPreprocessorOnly() const override;
325 TranslationUnitKind getTranslationUnitKind() override;
326 bool hasPCHSupport() const override;
327 bool hasASTFileSupport() const override;
328 bool hasIRSupport() const override;
329 bool hasCIRSupport() const override;
330 bool hasCodeCompletionSupport() const override;
331};
332
333} // end namespace clang
334
335#endif
336