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1 //===--- Execution.h - Executing clang frontend actions -*- 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 framework for executing clang frontend actions.
10 //
11 //  The framework can be extended to support different execution plans including
12 //  standalone execution on the given TUs or parallel execution on all TUs in
13 //  the codebase.
14 //
15 //  In order to enable multiprocessing execution, tool actions are expected to
16 //  output result into the ToolResults provided by the executor. The
17 //  `ToolResults` is an interface that abstracts how results are stored e.g.
18 //  in-memory for standalone execution or on-disk for large-scale execution.
19 //
20 //  New executors can be registered as ToolExecutorPlugins via the
21 //  `ToolExecutorPluginRegistry`. CLI tools can use
22 //  `createExecutorFromCommandLineArgs` to create a specific registered executor
23 //  according to the command-line arguments.
24 //
25 //===----------------------------------------------------------------------===//
26 
27 #ifndef LLVM_CLANG_TOOLING_EXECUTION_H
28 #define LLVM_CLANG_TOOLING_EXECUTION_H
29 
30 #include "clang/Tooling/CommonOptionsParser.h"
31 #include "clang/Tooling/Tooling.h"
32 #include "llvm/Support/Error.h"
33 #include "llvm/Support/Registry.h"
34 #include "llvm/Support/StringSaver.h"
35 
36 namespace clang {
37 namespace tooling {
38 
39 extern llvm::cl::opt<std::string> ExecutorName;
40 
41 /// An abstraction for the result of a tool execution. For example, the
42 /// underlying result can be in-memory or on-disk.
43 ///
44 /// Results should be string key-value pairs. For example, a refactoring tool
45 /// can use source location as key and a replacement in YAML format as value.
46 class ToolResults {
47 public:
48   virtual ~ToolResults() = default;
49   virtual void addResult(StringRef Key, StringRef Value) = 0;
50   virtual std::vector<std::pair<llvm::StringRef, llvm::StringRef>>
51   AllKVResults() = 0;
52   virtual void forEachResult(
53       llvm::function_ref<void(StringRef Key, StringRef Value)> Callback) = 0;
54 };
55 
56 /// Stores the key-value results in memory. It maintains the lifetime of
57 /// the result. Clang tools using this class are expected to generate a small
58 /// set of different results, or a large set of duplicated results.
59 class InMemoryToolResults : public ToolResults {
60 public:
InMemoryToolResults()61   InMemoryToolResults() : Strings(Arena) {}
62   void addResult(StringRef Key, StringRef Value) override;
63   std::vector<std::pair<llvm::StringRef, llvm::StringRef>>
64   AllKVResults() override;
65   void forEachResult(llvm::function_ref<void(StringRef Key, StringRef Value)>
66                          Callback) override;
67 
68 private:
69   llvm::BumpPtrAllocator Arena;
70   llvm::UniqueStringSaver Strings;
71 
72   std::vector<std::pair<llvm::StringRef, llvm::StringRef>> KVResults;
73 };
74 
75 /// The context of an execution, including the information about
76 /// compilation and results.
77 class ExecutionContext {
78 public:
~ExecutionContext()79   virtual ~ExecutionContext() {}
80 
81   /// Initializes a context. This does not take ownership of `Results`.
ExecutionContext(ToolResults * Results)82   explicit ExecutionContext(ToolResults *Results) : Results(Results) {}
83 
84   /// Adds a KV pair to the result container of this execution.
85   void reportResult(StringRef Key, StringRef Value);
86 
87   // Returns the source control system's revision number if applicable.
88   // Otherwise returns an empty string.
getRevision()89   virtual std::string getRevision() { return ""; }
90 
91   // Returns the corpus being analyzed, e.g. "llvm" for the LLVM codebase, if
92   // applicable.
getCorpus()93   virtual std::string getCorpus() { return ""; }
94 
95   // Returns the currently processed compilation unit if available.
getCurrentCompilationUnit()96   virtual std::string getCurrentCompilationUnit() { return ""; }
97 
98 private:
99   ToolResults *Results;
100 };
101 
102 /// Interface for executing clang frontend actions.
103 ///
104 /// This can be extended to support running tool actions in different
105 /// execution mode, e.g. on a specific set of TUs or many TUs in parallel.
106 ///
107 ///  New executors can be registered as ToolExecutorPlugins via the
108 ///  `ToolExecutorPluginRegistry`. CLI tools can use
109 ///  `createExecutorFromCommandLineArgs` to create a specific registered
110 ///  executor according to the command-line arguments.
111 class ToolExecutor {
112 public:
~ToolExecutor()113   virtual ~ToolExecutor() {}
114 
115   /// Returns the name of a specific executor.
116   virtual StringRef getExecutorName() const = 0;
117 
118   /// Executes each action with a corresponding arguments adjuster.
119   virtual llvm::Error
120   execute(llvm::ArrayRef<
121           std::pair<std::unique_ptr<FrontendActionFactory>, ArgumentsAdjuster>>
122               Actions) = 0;
123 
124   /// Convenient functions for the above `execute`.
125   llvm::Error execute(std::unique_ptr<FrontendActionFactory> Action);
126   /// Executes an action with an argument adjuster.
127   llvm::Error execute(std::unique_ptr<FrontendActionFactory> Action,
128                       ArgumentsAdjuster Adjuster);
129 
130   /// Returns a reference to the execution context.
131   ///
132   /// This should be passed to tool callbacks, and tool callbacks should report
133   /// results via the returned context.
134   virtual ExecutionContext *getExecutionContext() = 0;
135 
136   /// Returns a reference to the result container.
137   ///
138   /// NOTE: This should only be used after the execution finishes. Tool
139   /// callbacks should report results via `ExecutionContext` instead.
140   virtual ToolResults *getToolResults() = 0;
141 
142   /// Map a virtual file to be used while running the tool.
143   ///
144   /// \param FilePath The path at which the content will be mapped.
145   /// \param Content A buffer of the file's content.
146   virtual void mapVirtualFile(StringRef FilePath, StringRef Content) = 0;
147 };
148 
149 /// Interface for factories that create specific executors. This is also
150 /// used as a plugin to be registered into ToolExecutorPluginRegistry.
151 class ToolExecutorPlugin {
152 public:
~ToolExecutorPlugin()153   virtual ~ToolExecutorPlugin() {}
154 
155   /// Create an `ToolExecutor`.
156   ///
157   /// `OptionsParser` can be consumed (e.g. moved) if the creation succeeds.
158   virtual llvm::Expected<std::unique_ptr<ToolExecutor>>
159   create(CommonOptionsParser &OptionsParser) = 0;
160 };
161 
162 /// This creates a ToolExecutor that is in the global registry based on
163 /// commandline arguments.
164 ///
165 /// This picks the right executor based on the `--executor` option. This parses
166 /// the commandline arguments with `CommonOptionsParser`, so caller does not
167 /// need to parse again.
168 ///
169 /// By default, this creates a `StandaloneToolExecutor` ("standalone") if
170 /// `--executor` is not provided.
171 llvm::Expected<std::unique_ptr<ToolExecutor>>
172 createExecutorFromCommandLineArgs(int &argc, const char **argv,
173                                   llvm::cl::OptionCategory &Category,
174                                   const char *Overview = nullptr);
175 
176 namespace internal {
177 llvm::Expected<std::unique_ptr<ToolExecutor>>
178 createExecutorFromCommandLineArgsImpl(int &argc, const char **argv,
179                                       llvm::cl::OptionCategory &Category,
180                                       const char *Overview = nullptr);
181 } // end namespace internal
182 
183 } // end namespace tooling
184 } // end namespace clang
185 
186 #endif // LLVM_CLANG_TOOLING_EXECUTION_H
187