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