llvm/clang-tools-extra/clangd/refactor/tweaks/ExtractFunction.cpp

//===--- ExtractFunction.cpp -------------------------------------*- C++-*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Extracts statements to a new function and replaces the statements with a
// call to the new function.
// Before:
//   void f(int a) {
//     [[if(a < 5)
//       a = 5;]]
//   }
// After:
//   void extracted(int &a) {
//     if(a < 5)
//       a = 5;
//   }
//   void f(int a) {
//     extracted(a);
//   }
//
// - Only extract statements
// - Extracts from non-templated free functions only.
// - Parameters are const only if the declaration was const
//   - Always passed by l-value reference
// - Void return type
// - Cannot extract declarations that will be needed in the original function
//   after extraction.
// - Checks for broken control flow (break/continue without loop/switch)
//
// 1. ExtractFunction is the tweak subclass
//    - Prepare does basic analysis of the selection and is therefore fast.
//      Successful prepare doesn't always mean we can apply the tweak.
//    - Apply does a more detailed analysis and can be slower. In case of
//      failure, we let the user know that we are unable to perform extraction.
// 2. ExtractionZone store information about the range being extracted and the
//    enclosing function.
// 3. NewFunction stores properties of the extracted function and provides
//    methods for rendering it.
// 4. CapturedZoneInfo uses a RecursiveASTVisitor to capture information about
//    the extraction like declarations, existing return statements, etc.
// 5. getExtractedFunction is responsible for analyzing the CapturedZoneInfo and
//    creating a NewFunction.
//===----------------------------------------------------------------------===//

#include "AST.h"
#include "FindTarget.h"
#include "ParsedAST.h"
#include "Selection.h"
#include "SourceCode.h"
#include "refactor/Tweak.h"
#include "support/Logger.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclBase.h"
#include "clang/AST/NestedNameSpecifier.h"
#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/AST/Stmt.h"
#include "clang/Basic/LangOptions.h"
#include "clang/Basic/SourceLocation.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Tooling/Core/Replacement.h"
#include "clang/Tooling/Refactoring/Extract/SourceExtraction.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/raw_os_ostream.h"
#include <optional>

namespace clang {
namespace clangd {
namespace … // namespace
} // namespace clangd
} // namespace clang