450 lines
		
	
	
		
			17 KiB
		
	
	
	
		
			C++
		
	
	
	
			
		
		
	
	
			450 lines
		
	
	
		
			17 KiB
		
	
	
	
		
			C++
		
	
	
	
| //===--- ASTSelection.cpp - Clang refactoring library ---------------------===//
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| //
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| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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| // See https://llvm.org/LICENSE.txt for license information.
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| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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| //
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| //===----------------------------------------------------------------------===//
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| 
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| #include "clang/Tooling/Refactoring/ASTSelection.h"
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| #include "clang/AST/LexicallyOrderedRecursiveASTVisitor.h"
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| #include "clang/Lex/Lexer.h"
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| #include "llvm/Support/SaveAndRestore.h"
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| 
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| using namespace clang;
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| using namespace tooling;
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| 
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| namespace {
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| 
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| CharSourceRange getLexicalDeclRange(Decl *D, const SourceManager &SM,
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|                                     const LangOptions &LangOpts) {
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|   if (!isa<ObjCImplDecl>(D))
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|     return CharSourceRange::getTokenRange(D->getSourceRange());
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|   // Objective-C implementation declarations end at the '@' instead of the 'end'
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|   // keyword. Use the lexer to find the location right after 'end'.
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|   SourceRange R = D->getSourceRange();
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|   SourceLocation LocAfterEnd = Lexer::findLocationAfterToken(
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|       R.getEnd(), tok::raw_identifier, SM, LangOpts,
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|       /*SkipTrailingWhitespaceAndNewLine=*/false);
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|   return LocAfterEnd.isValid()
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|              ? CharSourceRange::getCharRange(R.getBegin(), LocAfterEnd)
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|              : CharSourceRange::getTokenRange(R);
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| }
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| 
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| /// Constructs the tree of selected AST nodes that either contain the location
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| /// of the cursor or overlap with the selection range.
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| class ASTSelectionFinder
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|     : public LexicallyOrderedRecursiveASTVisitor<ASTSelectionFinder> {
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| public:
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|   ASTSelectionFinder(SourceRange Selection, FileID TargetFile,
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|                      const ASTContext &Context)
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|       : LexicallyOrderedRecursiveASTVisitor(Context.getSourceManager()),
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|         SelectionBegin(Selection.getBegin()),
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|         SelectionEnd(Selection.getBegin() == Selection.getEnd()
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|                          ? SourceLocation()
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|                          : Selection.getEnd()),
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|         TargetFile(TargetFile), Context(Context) {
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|     // The TU decl is the root of the selected node tree.
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|     SelectionStack.push_back(
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|         SelectedASTNode(DynTypedNode::create(*Context.getTranslationUnitDecl()),
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|                         SourceSelectionKind::None));
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|   }
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| 
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|   Optional<SelectedASTNode> getSelectedASTNode() {
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|     assert(SelectionStack.size() == 1 && "stack was not popped");
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|     SelectedASTNode Result = std::move(SelectionStack.back());
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|     SelectionStack.pop_back();
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|     if (Result.Children.empty())
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|       return None;
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|     return std::move(Result);
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|   }
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| 
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|   bool TraversePseudoObjectExpr(PseudoObjectExpr *E) {
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|     // Avoid traversing the semantic expressions. They should be handled by
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|     // looking through the appropriate opaque expressions in order to build
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|     // a meaningful selection tree.
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|     llvm::SaveAndRestore<bool> LookThrough(LookThroughOpaqueValueExprs, true);
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|     return TraverseStmt(E->getSyntacticForm());
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|   }
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| 
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|   bool TraverseOpaqueValueExpr(OpaqueValueExpr *E) {
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|     if (!LookThroughOpaqueValueExprs)
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|       return true;
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|     llvm::SaveAndRestore<bool> LookThrough(LookThroughOpaqueValueExprs, false);
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|     return TraverseStmt(E->getSourceExpr());
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|   }
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| 
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|   bool TraverseDecl(Decl *D) {
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|     if (isa<TranslationUnitDecl>(D))
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|       return LexicallyOrderedRecursiveASTVisitor::TraverseDecl(D);
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|     if (D->isImplicit())
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|       return true;
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| 
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|     // Check if this declaration is written in the file of interest.
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|     const SourceRange DeclRange = D->getSourceRange();
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|     const SourceManager &SM = Context.getSourceManager();
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|     SourceLocation FileLoc;
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|     if (DeclRange.getBegin().isMacroID() && !DeclRange.getEnd().isMacroID())
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|       FileLoc = DeclRange.getEnd();
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|     else
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|       FileLoc = SM.getSpellingLoc(DeclRange.getBegin());
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|     if (SM.getFileID(FileLoc) != TargetFile)
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|       return true;
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| 
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|     SourceSelectionKind SelectionKind =
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|         selectionKindFor(getLexicalDeclRange(D, SM, Context.getLangOpts()));
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|     SelectionStack.push_back(
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|         SelectedASTNode(DynTypedNode::create(*D), SelectionKind));
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|     LexicallyOrderedRecursiveASTVisitor::TraverseDecl(D);
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|     popAndAddToSelectionIfSelected(SelectionKind);
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| 
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|     if (DeclRange.getEnd().isValid() &&
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|         SM.isBeforeInTranslationUnit(SelectionEnd.isValid() ? SelectionEnd
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|                                                             : SelectionBegin,
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|                                      DeclRange.getEnd())) {
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|       // Stop early when we've reached a declaration after the selection.
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|       return false;
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|     }
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|     return true;
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|   }
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| 
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|   bool TraverseStmt(Stmt *S) {
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|     if (!S)
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|       return true;
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|     if (auto *Opaque = dyn_cast<OpaqueValueExpr>(S))
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|       return TraverseOpaqueValueExpr(Opaque);
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|     // Avoid selecting implicit 'this' expressions.
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|     if (auto *TE = dyn_cast<CXXThisExpr>(S)) {
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|       if (TE->isImplicit())
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|         return true;
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|     }
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|     // FIXME (Alex Lorenz): Improve handling for macro locations.
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|     SourceSelectionKind SelectionKind =
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|         selectionKindFor(CharSourceRange::getTokenRange(S->getSourceRange()));
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|     SelectionStack.push_back(
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|         SelectedASTNode(DynTypedNode::create(*S), SelectionKind));
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|     LexicallyOrderedRecursiveASTVisitor::TraverseStmt(S);
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|     popAndAddToSelectionIfSelected(SelectionKind);
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|     return true;
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|   }
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| 
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| private:
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|   void popAndAddToSelectionIfSelected(SourceSelectionKind SelectionKind) {
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|     SelectedASTNode Node = std::move(SelectionStack.back());
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|     SelectionStack.pop_back();
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|     if (SelectionKind != SourceSelectionKind::None || !Node.Children.empty())
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|       SelectionStack.back().Children.push_back(std::move(Node));
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|   }
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| 
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|   SourceSelectionKind selectionKindFor(CharSourceRange Range) {
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|     SourceLocation End = Range.getEnd();
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|     const SourceManager &SM = Context.getSourceManager();
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|     if (Range.isTokenRange())
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|       End = Lexer::getLocForEndOfToken(End, 0, SM, Context.getLangOpts());
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|     if (!SourceLocation::isPairOfFileLocations(Range.getBegin(), End))
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|       return SourceSelectionKind::None;
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|     if (!SelectionEnd.isValid()) {
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|       // Do a quick check when the selection is of length 0.
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|       if (SM.isPointWithin(SelectionBegin, Range.getBegin(), End))
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|         return SourceSelectionKind::ContainsSelection;
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|       return SourceSelectionKind::None;
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|     }
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|     bool HasStart = SM.isPointWithin(SelectionBegin, Range.getBegin(), End);
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|     bool HasEnd = SM.isPointWithin(SelectionEnd, Range.getBegin(), End);
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|     if (HasStart && HasEnd)
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|       return SourceSelectionKind::ContainsSelection;
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|     if (SM.isPointWithin(Range.getBegin(), SelectionBegin, SelectionEnd) &&
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|         SM.isPointWithin(End, SelectionBegin, SelectionEnd))
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|       return SourceSelectionKind::InsideSelection;
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|     // Ensure there's at least some overlap with the 'start'/'end' selection
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|     // types.
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|     if (HasStart && SelectionBegin != End)
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|       return SourceSelectionKind::ContainsSelectionStart;
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|     if (HasEnd && SelectionEnd != Range.getBegin())
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|       return SourceSelectionKind::ContainsSelectionEnd;
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| 
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|     return SourceSelectionKind::None;
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|   }
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| 
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|   const SourceLocation SelectionBegin, SelectionEnd;
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|   FileID TargetFile;
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|   const ASTContext &Context;
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|   std::vector<SelectedASTNode> SelectionStack;
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|   /// Controls whether we can traverse through the OpaqueValueExpr. This is
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|   /// typically enabled during the traversal of syntactic form for
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|   /// PseudoObjectExprs.
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|   bool LookThroughOpaqueValueExprs = false;
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| };
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| 
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| } // end anonymous namespace
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| 
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| Optional<SelectedASTNode>
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| clang::tooling::findSelectedASTNodes(const ASTContext &Context,
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|                                      SourceRange SelectionRange) {
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|   assert(SelectionRange.isValid() &&
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|          SourceLocation::isPairOfFileLocations(SelectionRange.getBegin(),
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|                                                SelectionRange.getEnd()) &&
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|          "Expected a file range");
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|   FileID TargetFile =
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|       Context.getSourceManager().getFileID(SelectionRange.getBegin());
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|   assert(Context.getSourceManager().getFileID(SelectionRange.getEnd()) ==
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|              TargetFile &&
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|          "selection range must span one file");
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| 
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|   ASTSelectionFinder Visitor(SelectionRange, TargetFile, Context);
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|   Visitor.TraverseDecl(Context.getTranslationUnitDecl());
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|   return Visitor.getSelectedASTNode();
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| }
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| 
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| static const char *selectionKindToString(SourceSelectionKind Kind) {
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|   switch (Kind) {
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|   case SourceSelectionKind::None:
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|     return "none";
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|   case SourceSelectionKind::ContainsSelection:
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|     return "contains-selection";
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|   case SourceSelectionKind::ContainsSelectionStart:
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|     return "contains-selection-start";
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|   case SourceSelectionKind::ContainsSelectionEnd:
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|     return "contains-selection-end";
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|   case SourceSelectionKind::InsideSelection:
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|     return "inside";
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|   }
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|   llvm_unreachable("invalid selection kind");
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| }
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| 
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| static void dump(const SelectedASTNode &Node, llvm::raw_ostream &OS,
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|                  unsigned Indent = 0) {
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|   OS.indent(Indent * 2);
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|   if (const Decl *D = Node.Node.get<Decl>()) {
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|     OS << D->getDeclKindName() << "Decl";
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|     if (const auto *ND = dyn_cast<NamedDecl>(D))
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|       OS << " \"" << ND->getDeclName() << '"';
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|   } else if (const Stmt *S = Node.Node.get<Stmt>()) {
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|     OS << S->getStmtClassName();
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|   }
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|   OS << ' ' << selectionKindToString(Node.SelectionKind) << "\n";
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|   for (const auto &Child : Node.Children)
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|     dump(Child, OS, Indent + 1);
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| }
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| 
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| void SelectedASTNode::dump(llvm::raw_ostream &OS) const { ::dump(*this, OS); }
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| 
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| /// Returns true if the given node has any direct children with the following
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| /// selection kind.
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| ///
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| /// Note: The direct children also include children of direct children with the
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| /// "None" selection kind.
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| static bool hasAnyDirectChildrenWithKind(const SelectedASTNode &Node,
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|                                          SourceSelectionKind Kind) {
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|   assert(Kind != SourceSelectionKind::None && "invalid predicate!");
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|   for (const auto &Child : Node.Children) {
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|     if (Child.SelectionKind == Kind)
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|       return true;
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|     if (Child.SelectionKind == SourceSelectionKind::None)
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|       return hasAnyDirectChildrenWithKind(Child, Kind);
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|   }
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|   return false;
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| }
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| 
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| namespace {
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| struct SelectedNodeWithParents {
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|   SelectedASTNode::ReferenceType Node;
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|   llvm::SmallVector<SelectedASTNode::ReferenceType, 8> Parents;
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| 
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|   /// Canonicalizes the given selection by selecting different related AST nodes
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|   /// when it makes sense to do so.
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|   void canonicalize();
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| };
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| 
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| enum SelectionCanonicalizationAction { KeepSelection, SelectParent };
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| 
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| /// Returns the canonicalization action which should be applied to the
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| /// selected statement.
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| SelectionCanonicalizationAction
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| getSelectionCanonizalizationAction(const Stmt *S, const Stmt *Parent) {
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|   // Select the parent expression when:
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|   // - The string literal in ObjC string literal is selected, e.g.:
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|   //     @"test"   becomes   @"test"
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|   //      ~~~~~~             ~~~~~~~
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|   if (isa<StringLiteral>(S) && isa<ObjCStringLiteral>(Parent))
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|     return SelectParent;
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|   // The entire call should be selected when just the member expression
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|   // that refers to the method or the decl ref that refers to the function
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|   // is selected.
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|   //    f.call(args)  becomes  f.call(args)
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|   //      ~~~~                 ~~~~~~~~~~~~
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|   //    func(args)  becomes  func(args)
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|   //    ~~~~                 ~~~~~~~~~~
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|   else if (const auto *CE = dyn_cast<CallExpr>(Parent)) {
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|     if ((isa<MemberExpr>(S) || isa<DeclRefExpr>(S)) &&
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|         CE->getCallee()->IgnoreImpCasts() == S)
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|       return SelectParent;
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|   }
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|   // FIXME: Syntactic form -> Entire pseudo-object expr.
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|   return KeepSelection;
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| }
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| 
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| } // end anonymous namespace
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| 
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| void SelectedNodeWithParents::canonicalize() {
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|   const Stmt *S = Node.get().Node.get<Stmt>();
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|   assert(S && "non statement selection!");
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|   const Stmt *Parent = Parents[Parents.size() - 1].get().Node.get<Stmt>();
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|   if (!Parent)
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|     return;
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| 
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|   // Look through the implicit casts in the parents.
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|   unsigned ParentIndex = 1;
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|   for (; (ParentIndex + 1) <= Parents.size() && isa<ImplicitCastExpr>(Parent);
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|        ++ParentIndex) {
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|     const Stmt *NewParent =
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|         Parents[Parents.size() - ParentIndex - 1].get().Node.get<Stmt>();
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|     if (!NewParent)
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|       break;
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|     Parent = NewParent;
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|   }
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| 
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|   switch (getSelectionCanonizalizationAction(S, Parent)) {
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|   case SelectParent:
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|     Node = Parents[Parents.size() - ParentIndex];
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|     for (; ParentIndex != 0; --ParentIndex)
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|       Parents.pop_back();
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|     break;
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|   case KeepSelection:
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|     break;
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|   }
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| }
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| 
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| /// Finds the set of bottom-most selected AST nodes that are in the selection
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| /// tree with the specified selection kind.
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| ///
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| /// For example, given the following selection tree:
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| ///
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| /// FunctionDecl "f" contains-selection
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| ///   CompoundStmt contains-selection [#1]
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| ///     CallExpr inside
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| ///     ImplicitCastExpr inside
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| ///       DeclRefExpr inside
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| ///     IntegerLiteral inside
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| ///     IntegerLiteral inside
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| /// FunctionDecl "f2" contains-selection
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| ///   CompoundStmt contains-selection [#2]
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| ///     CallExpr inside
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| ///     ImplicitCastExpr inside
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| ///       DeclRefExpr inside
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| ///     IntegerLiteral inside
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| ///     IntegerLiteral inside
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| ///
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| /// This function will find references to nodes #1 and #2 when searching for the
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| /// \c ContainsSelection kind.
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| static void findDeepestWithKind(
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|     const SelectedASTNode &ASTSelection,
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|     llvm::SmallVectorImpl<SelectedNodeWithParents> &MatchingNodes,
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|     SourceSelectionKind Kind,
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|     llvm::SmallVectorImpl<SelectedASTNode::ReferenceType> &ParentStack) {
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|   if (ASTSelection.Node.get<DeclStmt>()) {
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|     // Select the entire decl stmt when any of its child declarations is the
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|     // bottom-most.
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|     for (const auto &Child : ASTSelection.Children) {
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|       if (!hasAnyDirectChildrenWithKind(Child, Kind)) {
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|         MatchingNodes.push_back(SelectedNodeWithParents{
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|             std::cref(ASTSelection), {ParentStack.begin(), ParentStack.end()}});
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|         return;
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|       }
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|     }
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|   } else {
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|     if (!hasAnyDirectChildrenWithKind(ASTSelection, Kind)) {
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|       // This node is the bottom-most.
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|       MatchingNodes.push_back(SelectedNodeWithParents{
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|           std::cref(ASTSelection), {ParentStack.begin(), ParentStack.end()}});
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|       return;
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|     }
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|   }
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|   // Search in the children.
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|   ParentStack.push_back(std::cref(ASTSelection));
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|   for (const auto &Child : ASTSelection.Children)
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|     findDeepestWithKind(Child, MatchingNodes, Kind, ParentStack);
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|   ParentStack.pop_back();
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| }
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| 
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| static void findDeepestWithKind(
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|     const SelectedASTNode &ASTSelection,
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|     llvm::SmallVectorImpl<SelectedNodeWithParents> &MatchingNodes,
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|     SourceSelectionKind Kind) {
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|   llvm::SmallVector<SelectedASTNode::ReferenceType, 16> ParentStack;
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|   findDeepestWithKind(ASTSelection, MatchingNodes, Kind, ParentStack);
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| }
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| 
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| Optional<CodeRangeASTSelection>
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| CodeRangeASTSelection::create(SourceRange SelectionRange,
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|                               const SelectedASTNode &ASTSelection) {
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|   // Code range is selected when the selection range is not empty.
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|   if (SelectionRange.getBegin() == SelectionRange.getEnd())
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|     return None;
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|   llvm::SmallVector<SelectedNodeWithParents, 4> ContainSelection;
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|   findDeepestWithKind(ASTSelection, ContainSelection,
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|                       SourceSelectionKind::ContainsSelection);
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|   // We are looking for a selection in one body of code, so let's focus on
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|   // one matching result.
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|   if (ContainSelection.size() != 1)
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|     return None;
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|   SelectedNodeWithParents &Selected = ContainSelection[0];
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|   if (!Selected.Node.get().Node.get<Stmt>())
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|     return None;
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|   const Stmt *CodeRangeStmt = Selected.Node.get().Node.get<Stmt>();
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|   if (!isa<CompoundStmt>(CodeRangeStmt)) {
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|     Selected.canonicalize();
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|     return CodeRangeASTSelection(Selected.Node, Selected.Parents,
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|                                  /*AreChildrenSelected=*/false);
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|   }
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|   // FIXME (Alex L): First selected SwitchCase means that first case statement.
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|   // is selected actually
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|   // (See https://github.com/apple/swift-clang & CompoundStmtRange).
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| 
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|   // FIXME (Alex L): Tweak selection rules for compound statements, see:
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|   // https://github.com/apple/swift-clang/blob/swift-4.1-branch/lib/Tooling/
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|   // Refactor/ASTSlice.cpp#L513
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|   // The user selected multiple statements in a compound statement.
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|   Selected.Parents.push_back(Selected.Node);
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|   return CodeRangeASTSelection(Selected.Node, Selected.Parents,
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|                                /*AreChildrenSelected=*/true);
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| }
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| 
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| static bool isFunctionLikeDeclaration(const Decl *D) {
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|   // FIXME (Alex L): Test for BlockDecl.
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|   return isa<FunctionDecl>(D) || isa<ObjCMethodDecl>(D);
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| }
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| 
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| bool CodeRangeASTSelection::isInFunctionLikeBodyOfCode() const {
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|   bool IsPrevCompound = false;
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|   // Scan through the parents (bottom-to-top) and check if the selection is
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|   // contained in a compound statement that's a body of a function/method
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|   // declaration.
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|   for (const auto &Parent : llvm::reverse(Parents)) {
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|     const DynTypedNode &Node = Parent.get().Node;
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|     if (const auto *D = Node.get<Decl>()) {
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|       if (isFunctionLikeDeclaration(D))
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|         return IsPrevCompound;
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|       // Stop the search at any type declaration to avoid returning true for
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|       // expressions in type declarations in functions, like:
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|       // function foo() { struct X {
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|       //   int m = /*selection:*/ 1 + 2 /*selection end*/; }; };
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|       if (isa<TypeDecl>(D))
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|         return false;
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|     }
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|     IsPrevCompound = Node.get<CompoundStmt>() != nullptr;
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|   }
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|   return false;
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| }
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| 
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| const Decl *CodeRangeASTSelection::getFunctionLikeNearestParent() const {
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|   for (const auto &Parent : llvm::reverse(Parents)) {
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|     const DynTypedNode &Node = Parent.get().Node;
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|     if (const auto *D = Node.get<Decl>()) {
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|       if (isFunctionLikeDeclaration(D))
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|         return D;
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|     }
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|   }
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|   return nullptr;
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| }
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