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1019 lines
33 KiB
1019 lines
33 KiB
//===- ASTDiff.cpp - AST differencing implementation-----------*- C++ -*- -===//
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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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// This file contains definitons for the AST differencing interface.
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//
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//===----------------------------------------------------------------------===//
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#include "clang/Tooling/ASTDiff/ASTDiff.h"
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#include "clang/AST/ParentMapContext.h"
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#include "clang/AST/RecursiveASTVisitor.h"
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#include "clang/Basic/SourceManager.h"
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#include "clang/Lex/Lexer.h"
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#include "llvm/ADT/PriorityQueue.h"
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#include <limits>
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#include <memory>
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#include <unordered_set>
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using namespace llvm;
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using namespace clang;
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namespace clang {
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namespace diff {
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namespace {
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/// Maps nodes of the left tree to ones on the right, and vice versa.
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class Mapping {
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public:
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Mapping() = default;
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Mapping(Mapping &&Other) = default;
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Mapping &operator=(Mapping &&Other) = default;
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Mapping(size_t Size) {
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SrcToDst = std::make_unique<NodeId[]>(Size);
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DstToSrc = std::make_unique<NodeId[]>(Size);
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}
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void link(NodeId Src, NodeId Dst) {
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SrcToDst[Src] = Dst, DstToSrc[Dst] = Src;
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}
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NodeId getDst(NodeId Src) const { return SrcToDst[Src]; }
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NodeId getSrc(NodeId Dst) const { return DstToSrc[Dst]; }
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bool hasSrc(NodeId Src) const { return getDst(Src).isValid(); }
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bool hasDst(NodeId Dst) const { return getSrc(Dst).isValid(); }
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private:
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std::unique_ptr<NodeId[]> SrcToDst, DstToSrc;
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};
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} // end anonymous namespace
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class ASTDiff::Impl {
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public:
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SyntaxTree::Impl &T1, &T2;
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Mapping TheMapping;
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Impl(SyntaxTree::Impl &T1, SyntaxTree::Impl &T2,
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const ComparisonOptions &Options);
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/// Matches nodes one-by-one based on their similarity.
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void computeMapping();
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// Compute Change for each node based on similarity.
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void computeChangeKinds(Mapping &M);
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NodeId getMapped(const std::unique_ptr<SyntaxTree::Impl> &Tree,
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NodeId Id) const {
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if (&*Tree == &T1)
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return TheMapping.getDst(Id);
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assert(&*Tree == &T2 && "Invalid tree.");
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return TheMapping.getSrc(Id);
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}
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private:
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// Returns true if the two subtrees are identical.
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bool identical(NodeId Id1, NodeId Id2) const;
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// Returns false if the nodes must not be mached.
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bool isMatchingPossible(NodeId Id1, NodeId Id2) const;
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// Returns true if the nodes' parents are matched.
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bool haveSameParents(const Mapping &M, NodeId Id1, NodeId Id2) const;
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// Uses an optimal albeit slow algorithm to compute a mapping between two
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// subtrees, but only if both have fewer nodes than MaxSize.
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void addOptimalMapping(Mapping &M, NodeId Id1, NodeId Id2) const;
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// Computes the ratio of common descendants between the two nodes.
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// Descendants are only considered to be equal when they are mapped in M.
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double getJaccardSimilarity(const Mapping &M, NodeId Id1, NodeId Id2) const;
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// Returns the node that has the highest degree of similarity.
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NodeId findCandidate(const Mapping &M, NodeId Id1) const;
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// Returns a mapping of identical subtrees.
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Mapping matchTopDown() const;
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// Tries to match any yet unmapped nodes, in a bottom-up fashion.
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void matchBottomUp(Mapping &M) const;
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const ComparisonOptions &Options;
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friend class ZhangShashaMatcher;
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};
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/// Represents the AST of a TranslationUnit.
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class SyntaxTree::Impl {
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public:
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Impl(SyntaxTree *Parent, ASTContext &AST);
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/// Constructs a tree from an AST node.
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Impl(SyntaxTree *Parent, Decl *N, ASTContext &AST);
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Impl(SyntaxTree *Parent, Stmt *N, ASTContext &AST);
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template <class T>
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Impl(SyntaxTree *Parent,
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std::enable_if_t<std::is_base_of<Stmt, T>::value, T> *Node,
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ASTContext &AST)
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: Impl(Parent, dyn_cast<Stmt>(Node), AST) {}
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template <class T>
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Impl(SyntaxTree *Parent,
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std::enable_if_t<std::is_base_of<Decl, T>::value, T> *Node,
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ASTContext &AST)
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: Impl(Parent, dyn_cast<Decl>(Node), AST) {}
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SyntaxTree *Parent;
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ASTContext &AST;
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PrintingPolicy TypePP;
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/// Nodes in preorder.
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std::vector<Node> Nodes;
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std::vector<NodeId> Leaves;
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// Maps preorder indices to postorder ones.
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std::vector<int> PostorderIds;
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std::vector<NodeId> NodesBfs;
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int getSize() const { return Nodes.size(); }
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NodeId getRootId() const { return 0; }
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PreorderIterator begin() const { return getRootId(); }
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PreorderIterator end() const { return getSize(); }
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const Node &getNode(NodeId Id) const { return Nodes[Id]; }
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Node &getMutableNode(NodeId Id) { return Nodes[Id]; }
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bool isValidNodeId(NodeId Id) const { return Id >= 0 && Id < getSize(); }
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void addNode(Node &N) { Nodes.push_back(N); }
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int getNumberOfDescendants(NodeId Id) const;
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bool isInSubtree(NodeId Id, NodeId SubtreeRoot) const;
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int findPositionInParent(NodeId Id, bool Shifted = false) const;
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std::string getRelativeName(const NamedDecl *ND,
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const DeclContext *Context) const;
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std::string getRelativeName(const NamedDecl *ND) const;
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std::string getNodeValue(NodeId Id) const;
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std::string getNodeValue(const Node &Node) const;
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std::string getDeclValue(const Decl *D) const;
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std::string getStmtValue(const Stmt *S) const;
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private:
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void initTree();
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void setLeftMostDescendants();
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};
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static bool isSpecializedNodeExcluded(const Decl *D) { return D->isImplicit(); }
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static bool isSpecializedNodeExcluded(const Stmt *S) { return false; }
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static bool isSpecializedNodeExcluded(CXXCtorInitializer *I) {
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return !I->isWritten();
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}
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template <class T>
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static bool isNodeExcluded(const SourceManager &SrcMgr, T *N) {
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if (!N)
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return true;
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SourceLocation SLoc = N->getSourceRange().getBegin();
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if (SLoc.isValid()) {
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// Ignore everything from other files.
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if (!SrcMgr.isInMainFile(SLoc))
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return true;
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// Ignore macros.
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if (SLoc != SrcMgr.getSpellingLoc(SLoc))
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return true;
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}
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return isSpecializedNodeExcluded(N);
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}
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namespace {
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// Sets Height, Parent and Children for each node.
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struct PreorderVisitor : public RecursiveASTVisitor<PreorderVisitor> {
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int Id = 0, Depth = 0;
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NodeId Parent;
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SyntaxTree::Impl &Tree;
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PreorderVisitor(SyntaxTree::Impl &Tree) : Tree(Tree) {}
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template <class T> std::tuple<NodeId, NodeId> PreTraverse(T *ASTNode) {
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NodeId MyId = Id;
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Tree.Nodes.emplace_back();
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Node &N = Tree.getMutableNode(MyId);
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N.Parent = Parent;
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N.Depth = Depth;
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N.ASTNode = DynTypedNode::create(*ASTNode);
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assert(!N.ASTNode.getNodeKind().isNone() &&
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"Expected nodes to have a valid kind.");
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if (Parent.isValid()) {
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Node &P = Tree.getMutableNode(Parent);
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P.Children.push_back(MyId);
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}
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Parent = MyId;
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++Id;
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++Depth;
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return std::make_tuple(MyId, Tree.getNode(MyId).Parent);
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}
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void PostTraverse(std::tuple<NodeId, NodeId> State) {
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NodeId MyId, PreviousParent;
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std::tie(MyId, PreviousParent) = State;
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assert(MyId.isValid() && "Expecting to only traverse valid nodes.");
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Parent = PreviousParent;
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--Depth;
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Node &N = Tree.getMutableNode(MyId);
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N.RightMostDescendant = Id - 1;
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assert(N.RightMostDescendant >= 0 &&
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N.RightMostDescendant < Tree.getSize() &&
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"Rightmost descendant must be a valid tree node.");
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if (N.isLeaf())
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Tree.Leaves.push_back(MyId);
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N.Height = 1;
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for (NodeId Child : N.Children)
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N.Height = std::max(N.Height, 1 + Tree.getNode(Child).Height);
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}
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bool TraverseDecl(Decl *D) {
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if (isNodeExcluded(Tree.AST.getSourceManager(), D))
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return true;
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auto SavedState = PreTraverse(D);
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RecursiveASTVisitor<PreorderVisitor>::TraverseDecl(D);
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PostTraverse(SavedState);
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return true;
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}
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bool TraverseStmt(Stmt *S) {
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if (auto *E = dyn_cast_or_null<Expr>(S))
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S = E->IgnoreImplicit();
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if (isNodeExcluded(Tree.AST.getSourceManager(), S))
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return true;
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auto SavedState = PreTraverse(S);
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RecursiveASTVisitor<PreorderVisitor>::TraverseStmt(S);
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PostTraverse(SavedState);
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return true;
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}
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bool TraverseType(QualType T) { return true; }
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bool TraverseConstructorInitializer(CXXCtorInitializer *Init) {
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if (isNodeExcluded(Tree.AST.getSourceManager(), Init))
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return true;
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auto SavedState = PreTraverse(Init);
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RecursiveASTVisitor<PreorderVisitor>::TraverseConstructorInitializer(Init);
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PostTraverse(SavedState);
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return true;
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}
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};
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} // end anonymous namespace
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SyntaxTree::Impl::Impl(SyntaxTree *Parent, ASTContext &AST)
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: Parent(Parent), AST(AST), TypePP(AST.getLangOpts()) {
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TypePP.AnonymousTagLocations = false;
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}
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SyntaxTree::Impl::Impl(SyntaxTree *Parent, Decl *N, ASTContext &AST)
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: Impl(Parent, AST) {
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PreorderVisitor PreorderWalker(*this);
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PreorderWalker.TraverseDecl(N);
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initTree();
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}
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SyntaxTree::Impl::Impl(SyntaxTree *Parent, Stmt *N, ASTContext &AST)
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: Impl(Parent, AST) {
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PreorderVisitor PreorderWalker(*this);
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PreorderWalker.TraverseStmt(N);
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initTree();
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}
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static std::vector<NodeId> getSubtreePostorder(const SyntaxTree::Impl &Tree,
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NodeId Root) {
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std::vector<NodeId> Postorder;
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std::function<void(NodeId)> Traverse = [&](NodeId Id) {
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const Node &N = Tree.getNode(Id);
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for (NodeId Child : N.Children)
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Traverse(Child);
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Postorder.push_back(Id);
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};
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Traverse(Root);
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return Postorder;
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}
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static std::vector<NodeId> getSubtreeBfs(const SyntaxTree::Impl &Tree,
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NodeId Root) {
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std::vector<NodeId> Ids;
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size_t Expanded = 0;
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Ids.push_back(Root);
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while (Expanded < Ids.size())
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for (NodeId Child : Tree.getNode(Ids[Expanded++]).Children)
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Ids.push_back(Child);
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return Ids;
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}
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void SyntaxTree::Impl::initTree() {
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setLeftMostDescendants();
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int PostorderId = 0;
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PostorderIds.resize(getSize());
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std::function<void(NodeId)> PostorderTraverse = [&](NodeId Id) {
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for (NodeId Child : getNode(Id).Children)
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PostorderTraverse(Child);
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PostorderIds[Id] = PostorderId;
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++PostorderId;
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};
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PostorderTraverse(getRootId());
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NodesBfs = getSubtreeBfs(*this, getRootId());
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}
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void SyntaxTree::Impl::setLeftMostDescendants() {
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for (NodeId Leaf : Leaves) {
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getMutableNode(Leaf).LeftMostDescendant = Leaf;
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NodeId Parent, Cur = Leaf;
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while ((Parent = getNode(Cur).Parent).isValid() &&
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getNode(Parent).Children[0] == Cur) {
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Cur = Parent;
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getMutableNode(Cur).LeftMostDescendant = Leaf;
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}
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}
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}
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int SyntaxTree::Impl::getNumberOfDescendants(NodeId Id) const {
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return getNode(Id).RightMostDescendant - Id + 1;
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}
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bool SyntaxTree::Impl::isInSubtree(NodeId Id, NodeId SubtreeRoot) const {
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return Id >= SubtreeRoot && Id <= getNode(SubtreeRoot).RightMostDescendant;
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}
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int SyntaxTree::Impl::findPositionInParent(NodeId Id, bool Shifted) const {
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NodeId Parent = getNode(Id).Parent;
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if (Parent.isInvalid())
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return 0;
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const auto &Siblings = getNode(Parent).Children;
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int Position = 0;
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for (size_t I = 0, E = Siblings.size(); I < E; ++I) {
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if (Shifted)
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Position += getNode(Siblings[I]).Shift;
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if (Siblings[I] == Id) {
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Position += I;
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return Position;
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}
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}
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llvm_unreachable("Node not found in parent's children.");
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}
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// Returns the qualified name of ND. If it is subordinate to Context,
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// then the prefix of the latter is removed from the returned value.
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std::string
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SyntaxTree::Impl::getRelativeName(const NamedDecl *ND,
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const DeclContext *Context) const {
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std::string Val = ND->getQualifiedNameAsString();
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std::string ContextPrefix;
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if (!Context)
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return Val;
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if (auto *Namespace = dyn_cast<NamespaceDecl>(Context))
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ContextPrefix = Namespace->getQualifiedNameAsString();
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else if (auto *Record = dyn_cast<RecordDecl>(Context))
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ContextPrefix = Record->getQualifiedNameAsString();
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else if (AST.getLangOpts().CPlusPlus11)
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if (auto *Tag = dyn_cast<TagDecl>(Context))
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ContextPrefix = Tag->getQualifiedNameAsString();
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// Strip the qualifier, if Val refers to something in the current scope.
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// But leave one leading ':' in place, so that we know that this is a
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// relative path.
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if (!ContextPrefix.empty() && StringRef(Val).startswith(ContextPrefix))
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Val = Val.substr(ContextPrefix.size() + 1);
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return Val;
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}
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std::string SyntaxTree::Impl::getRelativeName(const NamedDecl *ND) const {
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return getRelativeName(ND, ND->getDeclContext());
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}
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static const DeclContext *getEnclosingDeclContext(ASTContext &AST,
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const Stmt *S) {
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while (S) {
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const auto &Parents = AST.getParents(*S);
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if (Parents.empty())
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return nullptr;
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const auto &P = Parents[0];
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if (const auto *D = P.get<Decl>())
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return D->getDeclContext();
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S = P.get<Stmt>();
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}
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return nullptr;
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}
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static std::string getInitializerValue(const CXXCtorInitializer *Init,
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const PrintingPolicy &TypePP) {
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if (Init->isAnyMemberInitializer())
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return std::string(Init->getAnyMember()->getName());
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if (Init->isBaseInitializer())
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return QualType(Init->getBaseClass(), 0).getAsString(TypePP);
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if (Init->isDelegatingInitializer())
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return Init->getTypeSourceInfo()->getType().getAsString(TypePP);
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llvm_unreachable("Unknown initializer type");
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}
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std::string SyntaxTree::Impl::getNodeValue(NodeId Id) const {
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return getNodeValue(getNode(Id));
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}
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std::string SyntaxTree::Impl::getNodeValue(const Node &N) const {
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const DynTypedNode &DTN = N.ASTNode;
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if (auto *S = DTN.get<Stmt>())
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return getStmtValue(S);
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if (auto *D = DTN.get<Decl>())
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return getDeclValue(D);
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if (auto *Init = DTN.get<CXXCtorInitializer>())
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return getInitializerValue(Init, TypePP);
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llvm_unreachable("Fatal: unhandled AST node.\n");
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}
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std::string SyntaxTree::Impl::getDeclValue(const Decl *D) const {
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std::string Value;
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if (auto *V = dyn_cast<ValueDecl>(D))
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return getRelativeName(V) + "(" + V->getType().getAsString(TypePP) + ")";
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if (auto *N = dyn_cast<NamedDecl>(D))
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Value += getRelativeName(N) + ";";
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if (auto *T = dyn_cast<TypedefNameDecl>(D))
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return Value + T->getUnderlyingType().getAsString(TypePP) + ";";
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if (auto *T = dyn_cast<TypeDecl>(D))
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if (T->getTypeForDecl())
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Value +=
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T->getTypeForDecl()->getCanonicalTypeInternal().getAsString(TypePP) +
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";";
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if (auto *U = dyn_cast<UsingDirectiveDecl>(D))
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return std::string(U->getNominatedNamespace()->getName());
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if (auto *A = dyn_cast<AccessSpecDecl>(D)) {
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CharSourceRange Range(A->getSourceRange(), false);
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return std::string(
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Lexer::getSourceText(Range, AST.getSourceManager(), AST.getLangOpts()));
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}
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return Value;
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}
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std::string SyntaxTree::Impl::getStmtValue(const Stmt *S) const {
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if (auto *U = dyn_cast<UnaryOperator>(S))
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return std::string(UnaryOperator::getOpcodeStr(U->getOpcode()));
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if (auto *B = dyn_cast<BinaryOperator>(S))
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return std::string(B->getOpcodeStr());
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if (auto *M = dyn_cast<MemberExpr>(S))
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return getRelativeName(M->getMemberDecl());
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if (auto *I = dyn_cast<IntegerLiteral>(S)) {
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SmallString<256> Str;
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I->getValue().toString(Str, /*Radix=*/10, /*Signed=*/false);
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return std::string(Str.str());
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}
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if (auto *F = dyn_cast<FloatingLiteral>(S)) {
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SmallString<256> Str;
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F->getValue().toString(Str);
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return std::string(Str.str());
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}
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if (auto *D = dyn_cast<DeclRefExpr>(S))
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return getRelativeName(D->getDecl(), getEnclosingDeclContext(AST, S));
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if (auto *String = dyn_cast<StringLiteral>(S))
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return std::string(String->getString());
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if (auto *B = dyn_cast<CXXBoolLiteralExpr>(S))
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return B->getValue() ? "true" : "false";
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return "";
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}
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/// Identifies a node in a subtree by its postorder offset, starting at 1.
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|
struct SNodeId {
|
|
int Id = 0;
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explicit SNodeId(int Id) : Id(Id) {}
|
|
explicit SNodeId() = default;
|
|
|
|
operator int() const { return Id; }
|
|
SNodeId &operator++() { return ++Id, *this; }
|
|
SNodeId &operator--() { return --Id, *this; }
|
|
SNodeId operator+(int Other) const { return SNodeId(Id + Other); }
|
|
};
|
|
|
|
class Subtree {
|
|
private:
|
|
/// The parent tree.
|
|
const SyntaxTree::Impl &Tree;
|
|
/// Maps SNodeIds to original ids.
|
|
std::vector<NodeId> RootIds;
|
|
/// Maps subtree nodes to their leftmost descendants wtihin the subtree.
|
|
std::vector<SNodeId> LeftMostDescendants;
|
|
|
|
public:
|
|
std::vector<SNodeId> KeyRoots;
|
|
|
|
Subtree(const SyntaxTree::Impl &Tree, NodeId SubtreeRoot) : Tree(Tree) {
|
|
RootIds = getSubtreePostorder(Tree, SubtreeRoot);
|
|
int NumLeaves = setLeftMostDescendants();
|
|
computeKeyRoots(NumLeaves);
|
|
}
|
|
int getSize() const { return RootIds.size(); }
|
|
NodeId getIdInRoot(SNodeId Id) const {
|
|
assert(Id > 0 && Id <= getSize() && "Invalid subtree node index.");
|
|
return RootIds[Id - 1];
|
|
}
|
|
const Node &getNode(SNodeId Id) const {
|
|
return Tree.getNode(getIdInRoot(Id));
|
|
}
|
|
SNodeId getLeftMostDescendant(SNodeId Id) const {
|
|
assert(Id > 0 && Id <= getSize() && "Invalid subtree node index.");
|
|
return LeftMostDescendants[Id - 1];
|
|
}
|
|
/// Returns the postorder index of the leftmost descendant in the subtree.
|
|
NodeId getPostorderOffset() const {
|
|
return Tree.PostorderIds[getIdInRoot(SNodeId(1))];
|
|
}
|
|
std::string getNodeValue(SNodeId Id) const {
|
|
return Tree.getNodeValue(getIdInRoot(Id));
|
|
}
|
|
|
|
private:
|
|
/// Returns the number of leafs in the subtree.
|
|
int setLeftMostDescendants() {
|
|
int NumLeaves = 0;
|
|
LeftMostDescendants.resize(getSize());
|
|
for (int I = 0; I < getSize(); ++I) {
|
|
SNodeId SI(I + 1);
|
|
const Node &N = getNode(SI);
|
|
NumLeaves += N.isLeaf();
|
|
assert(I == Tree.PostorderIds[getIdInRoot(SI)] - getPostorderOffset() &&
|
|
"Postorder traversal in subtree should correspond to traversal in "
|
|
"the root tree by a constant offset.");
|
|
LeftMostDescendants[I] = SNodeId(Tree.PostorderIds[N.LeftMostDescendant] -
|
|
getPostorderOffset());
|
|
}
|
|
return NumLeaves;
|
|
}
|
|
void computeKeyRoots(int Leaves) {
|
|
KeyRoots.resize(Leaves);
|
|
std::unordered_set<int> Visited;
|
|
int K = Leaves - 1;
|
|
for (SNodeId I(getSize()); I > 0; --I) {
|
|
SNodeId LeftDesc = getLeftMostDescendant(I);
|
|
if (Visited.count(LeftDesc))
|
|
continue;
|
|
assert(K >= 0 && "K should be non-negative");
|
|
KeyRoots[K] = I;
|
|
Visited.insert(LeftDesc);
|
|
--K;
|
|
}
|
|
}
|
|
};
|
|
|
|
/// Implementation of Zhang and Shasha's Algorithm for tree edit distance.
|
|
/// Computes an optimal mapping between two trees using only insertion,
|
|
/// deletion and update as edit actions (similar to the Levenshtein distance).
|
|
class ZhangShashaMatcher {
|
|
const ASTDiff::Impl &DiffImpl;
|
|
Subtree S1;
|
|
Subtree S2;
|
|
std::unique_ptr<std::unique_ptr<double[]>[]> TreeDist, ForestDist;
|
|
|
|
public:
|
|
ZhangShashaMatcher(const ASTDiff::Impl &DiffImpl, const SyntaxTree::Impl &T1,
|
|
const SyntaxTree::Impl &T2, NodeId Id1, NodeId Id2)
|
|
: DiffImpl(DiffImpl), S1(T1, Id1), S2(T2, Id2) {
|
|
TreeDist = std::make_unique<std::unique_ptr<double[]>[]>(
|
|
size_t(S1.getSize()) + 1);
|
|
ForestDist = std::make_unique<std::unique_ptr<double[]>[]>(
|
|
size_t(S1.getSize()) + 1);
|
|
for (int I = 0, E = S1.getSize() + 1; I < E; ++I) {
|
|
TreeDist[I] = std::make_unique<double[]>(size_t(S2.getSize()) + 1);
|
|
ForestDist[I] = std::make_unique<double[]>(size_t(S2.getSize()) + 1);
|
|
}
|
|
}
|
|
|
|
std::vector<std::pair<NodeId, NodeId>> getMatchingNodes() {
|
|
std::vector<std::pair<NodeId, NodeId>> Matches;
|
|
std::vector<std::pair<SNodeId, SNodeId>> TreePairs;
|
|
|
|
computeTreeDist();
|
|
|
|
bool RootNodePair = true;
|
|
|
|
TreePairs.emplace_back(SNodeId(S1.getSize()), SNodeId(S2.getSize()));
|
|
|
|
while (!TreePairs.empty()) {
|
|
SNodeId LastRow, LastCol, FirstRow, FirstCol, Row, Col;
|
|
std::tie(LastRow, LastCol) = TreePairs.back();
|
|
TreePairs.pop_back();
|
|
|
|
if (!RootNodePair) {
|
|
computeForestDist(LastRow, LastCol);
|
|
}
|
|
|
|
RootNodePair = false;
|
|
|
|
FirstRow = S1.getLeftMostDescendant(LastRow);
|
|
FirstCol = S2.getLeftMostDescendant(LastCol);
|
|
|
|
Row = LastRow;
|
|
Col = LastCol;
|
|
|
|
while (Row > FirstRow || Col > FirstCol) {
|
|
if (Row > FirstRow &&
|
|
ForestDist[Row - 1][Col] + 1 == ForestDist[Row][Col]) {
|
|
--Row;
|
|
} else if (Col > FirstCol &&
|
|
ForestDist[Row][Col - 1] + 1 == ForestDist[Row][Col]) {
|
|
--Col;
|
|
} else {
|
|
SNodeId LMD1 = S1.getLeftMostDescendant(Row);
|
|
SNodeId LMD2 = S2.getLeftMostDescendant(Col);
|
|
if (LMD1 == S1.getLeftMostDescendant(LastRow) &&
|
|
LMD2 == S2.getLeftMostDescendant(LastCol)) {
|
|
NodeId Id1 = S1.getIdInRoot(Row);
|
|
NodeId Id2 = S2.getIdInRoot(Col);
|
|
assert(DiffImpl.isMatchingPossible(Id1, Id2) &&
|
|
"These nodes must not be matched.");
|
|
Matches.emplace_back(Id1, Id2);
|
|
--Row;
|
|
--Col;
|
|
} else {
|
|
TreePairs.emplace_back(Row, Col);
|
|
Row = LMD1;
|
|
Col = LMD2;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
return Matches;
|
|
}
|
|
|
|
private:
|
|
/// We use a simple cost model for edit actions, which seems good enough.
|
|
/// Simple cost model for edit actions. This seems to make the matching
|
|
/// algorithm perform reasonably well.
|
|
/// The values range between 0 and 1, or infinity if this edit action should
|
|
/// always be avoided.
|
|
static constexpr double DeletionCost = 1;
|
|
static constexpr double InsertionCost = 1;
|
|
|
|
double getUpdateCost(SNodeId Id1, SNodeId Id2) {
|
|
if (!DiffImpl.isMatchingPossible(S1.getIdInRoot(Id1), S2.getIdInRoot(Id2)))
|
|
return std::numeric_limits<double>::max();
|
|
return S1.getNodeValue(Id1) != S2.getNodeValue(Id2);
|
|
}
|
|
|
|
void computeTreeDist() {
|
|
for (SNodeId Id1 : S1.KeyRoots)
|
|
for (SNodeId Id2 : S2.KeyRoots)
|
|
computeForestDist(Id1, Id2);
|
|
}
|
|
|
|
void computeForestDist(SNodeId Id1, SNodeId Id2) {
|
|
assert(Id1 > 0 && Id2 > 0 && "Expecting offsets greater than 0.");
|
|
SNodeId LMD1 = S1.getLeftMostDescendant(Id1);
|
|
SNodeId LMD2 = S2.getLeftMostDescendant(Id2);
|
|
|
|
ForestDist[LMD1][LMD2] = 0;
|
|
for (SNodeId D1 = LMD1 + 1; D1 <= Id1; ++D1) {
|
|
ForestDist[D1][LMD2] = ForestDist[D1 - 1][LMD2] + DeletionCost;
|
|
for (SNodeId D2 = LMD2 + 1; D2 <= Id2; ++D2) {
|
|
ForestDist[LMD1][D2] = ForestDist[LMD1][D2 - 1] + InsertionCost;
|
|
SNodeId DLMD1 = S1.getLeftMostDescendant(D1);
|
|
SNodeId DLMD2 = S2.getLeftMostDescendant(D2);
|
|
if (DLMD1 == LMD1 && DLMD2 == LMD2) {
|
|
double UpdateCost = getUpdateCost(D1, D2);
|
|
ForestDist[D1][D2] =
|
|
std::min({ForestDist[D1 - 1][D2] + DeletionCost,
|
|
ForestDist[D1][D2 - 1] + InsertionCost,
|
|
ForestDist[D1 - 1][D2 - 1] + UpdateCost});
|
|
TreeDist[D1][D2] = ForestDist[D1][D2];
|
|
} else {
|
|
ForestDist[D1][D2] =
|
|
std::min({ForestDist[D1 - 1][D2] + DeletionCost,
|
|
ForestDist[D1][D2 - 1] + InsertionCost,
|
|
ForestDist[DLMD1][DLMD2] + TreeDist[D1][D2]});
|
|
}
|
|
}
|
|
}
|
|
}
|
|
};
|
|
|
|
ASTNodeKind Node::getType() const { return ASTNode.getNodeKind(); }
|
|
|
|
StringRef Node::getTypeLabel() const { return getType().asStringRef(); }
|
|
|
|
llvm::Optional<std::string> Node::getQualifiedIdentifier() const {
|
|
if (auto *ND = ASTNode.get<NamedDecl>()) {
|
|
if (ND->getDeclName().isIdentifier())
|
|
return ND->getQualifiedNameAsString();
|
|
}
|
|
return llvm::None;
|
|
}
|
|
|
|
llvm::Optional<StringRef> Node::getIdentifier() const {
|
|
if (auto *ND = ASTNode.get<NamedDecl>()) {
|
|
if (ND->getDeclName().isIdentifier())
|
|
return ND->getName();
|
|
}
|
|
return llvm::None;
|
|
}
|
|
|
|
namespace {
|
|
// Compares nodes by their depth.
|
|
struct HeightLess {
|
|
const SyntaxTree::Impl &Tree;
|
|
HeightLess(const SyntaxTree::Impl &Tree) : Tree(Tree) {}
|
|
bool operator()(NodeId Id1, NodeId Id2) const {
|
|
return Tree.getNode(Id1).Height < Tree.getNode(Id2).Height;
|
|
}
|
|
};
|
|
} // end anonymous namespace
|
|
|
|
namespace {
|
|
// Priority queue for nodes, sorted descendingly by their height.
|
|
class PriorityList {
|
|
const SyntaxTree::Impl &Tree;
|
|
HeightLess Cmp;
|
|
std::vector<NodeId> Container;
|
|
PriorityQueue<NodeId, std::vector<NodeId>, HeightLess> List;
|
|
|
|
public:
|
|
PriorityList(const SyntaxTree::Impl &Tree)
|
|
: Tree(Tree), Cmp(Tree), List(Cmp, Container) {}
|
|
|
|
void push(NodeId id) { List.push(id); }
|
|
|
|
std::vector<NodeId> pop() {
|
|
int Max = peekMax();
|
|
std::vector<NodeId> Result;
|
|
if (Max == 0)
|
|
return Result;
|
|
while (peekMax() == Max) {
|
|
Result.push_back(List.top());
|
|
List.pop();
|
|
}
|
|
// TODO this is here to get a stable output, not a good heuristic
|
|
llvm::sort(Result);
|
|
return Result;
|
|
}
|
|
int peekMax() const {
|
|
if (List.empty())
|
|
return 0;
|
|
return Tree.getNode(List.top()).Height;
|
|
}
|
|
void open(NodeId Id) {
|
|
for (NodeId Child : Tree.getNode(Id).Children)
|
|
push(Child);
|
|
}
|
|
};
|
|
} // end anonymous namespace
|
|
|
|
bool ASTDiff::Impl::identical(NodeId Id1, NodeId Id2) const {
|
|
const Node &N1 = T1.getNode(Id1);
|
|
const Node &N2 = T2.getNode(Id2);
|
|
if (N1.Children.size() != N2.Children.size() ||
|
|
!isMatchingPossible(Id1, Id2) ||
|
|
T1.getNodeValue(Id1) != T2.getNodeValue(Id2))
|
|
return false;
|
|
for (size_t Id = 0, E = N1.Children.size(); Id < E; ++Id)
|
|
if (!identical(N1.Children[Id], N2.Children[Id]))
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
bool ASTDiff::Impl::isMatchingPossible(NodeId Id1, NodeId Id2) const {
|
|
return Options.isMatchingAllowed(T1.getNode(Id1), T2.getNode(Id2));
|
|
}
|
|
|
|
bool ASTDiff::Impl::haveSameParents(const Mapping &M, NodeId Id1,
|
|
NodeId Id2) const {
|
|
NodeId P1 = T1.getNode(Id1).Parent;
|
|
NodeId P2 = T2.getNode(Id2).Parent;
|
|
return (P1.isInvalid() && P2.isInvalid()) ||
|
|
(P1.isValid() && P2.isValid() && M.getDst(P1) == P2);
|
|
}
|
|
|
|
void ASTDiff::Impl::addOptimalMapping(Mapping &M, NodeId Id1,
|
|
NodeId Id2) const {
|
|
if (std::max(T1.getNumberOfDescendants(Id1), T2.getNumberOfDescendants(Id2)) >
|
|
Options.MaxSize)
|
|
return;
|
|
ZhangShashaMatcher Matcher(*this, T1, T2, Id1, Id2);
|
|
std::vector<std::pair<NodeId, NodeId>> R = Matcher.getMatchingNodes();
|
|
for (const auto &Tuple : R) {
|
|
NodeId Src = Tuple.first;
|
|
NodeId Dst = Tuple.second;
|
|
if (!M.hasSrc(Src) && !M.hasDst(Dst))
|
|
M.link(Src, Dst);
|
|
}
|
|
}
|
|
|
|
double ASTDiff::Impl::getJaccardSimilarity(const Mapping &M, NodeId Id1,
|
|
NodeId Id2) const {
|
|
int CommonDescendants = 0;
|
|
const Node &N1 = T1.getNode(Id1);
|
|
// Count the common descendants, excluding the subtree root.
|
|
for (NodeId Src = Id1 + 1; Src <= N1.RightMostDescendant; ++Src) {
|
|
NodeId Dst = M.getDst(Src);
|
|
CommonDescendants += int(Dst.isValid() && T2.isInSubtree(Dst, Id2));
|
|
}
|
|
// We need to subtract 1 to get the number of descendants excluding the root.
|
|
double Denominator = T1.getNumberOfDescendants(Id1) - 1 +
|
|
T2.getNumberOfDescendants(Id2) - 1 - CommonDescendants;
|
|
// CommonDescendants is less than the size of one subtree.
|
|
assert(Denominator >= 0 && "Expected non-negative denominator.");
|
|
if (Denominator == 0)
|
|
return 0;
|
|
return CommonDescendants / Denominator;
|
|
}
|
|
|
|
NodeId ASTDiff::Impl::findCandidate(const Mapping &M, NodeId Id1) const {
|
|
NodeId Candidate;
|
|
double HighestSimilarity = 0.0;
|
|
for (NodeId Id2 : T2) {
|
|
if (!isMatchingPossible(Id1, Id2))
|
|
continue;
|
|
if (M.hasDst(Id2))
|
|
continue;
|
|
double Similarity = getJaccardSimilarity(M, Id1, Id2);
|
|
if (Similarity >= Options.MinSimilarity && Similarity > HighestSimilarity) {
|
|
HighestSimilarity = Similarity;
|
|
Candidate = Id2;
|
|
}
|
|
}
|
|
return Candidate;
|
|
}
|
|
|
|
void ASTDiff::Impl::matchBottomUp(Mapping &M) const {
|
|
std::vector<NodeId> Postorder = getSubtreePostorder(T1, T1.getRootId());
|
|
for (NodeId Id1 : Postorder) {
|
|
if (Id1 == T1.getRootId() && !M.hasSrc(T1.getRootId()) &&
|
|
!M.hasDst(T2.getRootId())) {
|
|
if (isMatchingPossible(T1.getRootId(), T2.getRootId())) {
|
|
M.link(T1.getRootId(), T2.getRootId());
|
|
addOptimalMapping(M, T1.getRootId(), T2.getRootId());
|
|
}
|
|
break;
|
|
}
|
|
bool Matched = M.hasSrc(Id1);
|
|
const Node &N1 = T1.getNode(Id1);
|
|
bool MatchedChildren = llvm::any_of(
|
|
N1.Children, [&](NodeId Child) { return M.hasSrc(Child); });
|
|
if (Matched || !MatchedChildren)
|
|
continue;
|
|
NodeId Id2 = findCandidate(M, Id1);
|
|
if (Id2.isValid()) {
|
|
M.link(Id1, Id2);
|
|
addOptimalMapping(M, Id1, Id2);
|
|
}
|
|
}
|
|
}
|
|
|
|
Mapping ASTDiff::Impl::matchTopDown() const {
|
|
PriorityList L1(T1);
|
|
PriorityList L2(T2);
|
|
|
|
Mapping M(T1.getSize() + T2.getSize());
|
|
|
|
L1.push(T1.getRootId());
|
|
L2.push(T2.getRootId());
|
|
|
|
int Max1, Max2;
|
|
while (std::min(Max1 = L1.peekMax(), Max2 = L2.peekMax()) >
|
|
Options.MinHeight) {
|
|
if (Max1 > Max2) {
|
|
for (NodeId Id : L1.pop())
|
|
L1.open(Id);
|
|
continue;
|
|
}
|
|
if (Max2 > Max1) {
|
|
for (NodeId Id : L2.pop())
|
|
L2.open(Id);
|
|
continue;
|
|
}
|
|
std::vector<NodeId> H1, H2;
|
|
H1 = L1.pop();
|
|
H2 = L2.pop();
|
|
for (NodeId Id1 : H1) {
|
|
for (NodeId Id2 : H2) {
|
|
if (identical(Id1, Id2) && !M.hasSrc(Id1) && !M.hasDst(Id2)) {
|
|
for (int I = 0, E = T1.getNumberOfDescendants(Id1); I < E; ++I)
|
|
M.link(Id1 + I, Id2 + I);
|
|
}
|
|
}
|
|
}
|
|
for (NodeId Id1 : H1) {
|
|
if (!M.hasSrc(Id1))
|
|
L1.open(Id1);
|
|
}
|
|
for (NodeId Id2 : H2) {
|
|
if (!M.hasDst(Id2))
|
|
L2.open(Id2);
|
|
}
|
|
}
|
|
return M;
|
|
}
|
|
|
|
ASTDiff::Impl::Impl(SyntaxTree::Impl &T1, SyntaxTree::Impl &T2,
|
|
const ComparisonOptions &Options)
|
|
: T1(T1), T2(T2), Options(Options) {
|
|
computeMapping();
|
|
computeChangeKinds(TheMapping);
|
|
}
|
|
|
|
void ASTDiff::Impl::computeMapping() {
|
|
TheMapping = matchTopDown();
|
|
if (Options.StopAfterTopDown)
|
|
return;
|
|
matchBottomUp(TheMapping);
|
|
}
|
|
|
|
void ASTDiff::Impl::computeChangeKinds(Mapping &M) {
|
|
for (NodeId Id1 : T1) {
|
|
if (!M.hasSrc(Id1)) {
|
|
T1.getMutableNode(Id1).Change = Delete;
|
|
T1.getMutableNode(Id1).Shift -= 1;
|
|
}
|
|
}
|
|
for (NodeId Id2 : T2) {
|
|
if (!M.hasDst(Id2)) {
|
|
T2.getMutableNode(Id2).Change = Insert;
|
|
T2.getMutableNode(Id2).Shift -= 1;
|
|
}
|
|
}
|
|
for (NodeId Id1 : T1.NodesBfs) {
|
|
NodeId Id2 = M.getDst(Id1);
|
|
if (Id2.isInvalid())
|
|
continue;
|
|
if (!haveSameParents(M, Id1, Id2) ||
|
|
T1.findPositionInParent(Id1, true) !=
|
|
T2.findPositionInParent(Id2, true)) {
|
|
T1.getMutableNode(Id1).Shift -= 1;
|
|
T2.getMutableNode(Id2).Shift -= 1;
|
|
}
|
|
}
|
|
for (NodeId Id2 : T2.NodesBfs) {
|
|
NodeId Id1 = M.getSrc(Id2);
|
|
if (Id1.isInvalid())
|
|
continue;
|
|
Node &N1 = T1.getMutableNode(Id1);
|
|
Node &N2 = T2.getMutableNode(Id2);
|
|
if (Id1.isInvalid())
|
|
continue;
|
|
if (!haveSameParents(M, Id1, Id2) ||
|
|
T1.findPositionInParent(Id1, true) !=
|
|
T2.findPositionInParent(Id2, true)) {
|
|
N1.Change = N2.Change = Move;
|
|
}
|
|
if (T1.getNodeValue(Id1) != T2.getNodeValue(Id2)) {
|
|
N1.Change = N2.Change = (N1.Change == Move ? UpdateMove : Update);
|
|
}
|
|
}
|
|
}
|
|
|
|
ASTDiff::ASTDiff(SyntaxTree &T1, SyntaxTree &T2,
|
|
const ComparisonOptions &Options)
|
|
: DiffImpl(std::make_unique<Impl>(*T1.TreeImpl, *T2.TreeImpl, Options)) {}
|
|
|
|
ASTDiff::~ASTDiff() = default;
|
|
|
|
NodeId ASTDiff::getMapped(const SyntaxTree &SourceTree, NodeId Id) const {
|
|
return DiffImpl->getMapped(SourceTree.TreeImpl, Id);
|
|
}
|
|
|
|
SyntaxTree::SyntaxTree(ASTContext &AST)
|
|
: TreeImpl(std::make_unique<SyntaxTree::Impl>(
|
|
this, AST.getTranslationUnitDecl(), AST)) {}
|
|
|
|
SyntaxTree::~SyntaxTree() = default;
|
|
|
|
const ASTContext &SyntaxTree::getASTContext() const { return TreeImpl->AST; }
|
|
|
|
const Node &SyntaxTree::getNode(NodeId Id) const {
|
|
return TreeImpl->getNode(Id);
|
|
}
|
|
|
|
int SyntaxTree::getSize() const { return TreeImpl->getSize(); }
|
|
NodeId SyntaxTree::getRootId() const { return TreeImpl->getRootId(); }
|
|
SyntaxTree::PreorderIterator SyntaxTree::begin() const {
|
|
return TreeImpl->begin();
|
|
}
|
|
SyntaxTree::PreorderIterator SyntaxTree::end() const { return TreeImpl->end(); }
|
|
|
|
int SyntaxTree::findPositionInParent(NodeId Id) const {
|
|
return TreeImpl->findPositionInParent(Id);
|
|
}
|
|
|
|
std::pair<unsigned, unsigned>
|
|
SyntaxTree::getSourceRangeOffsets(const Node &N) const {
|
|
const SourceManager &SrcMgr = TreeImpl->AST.getSourceManager();
|
|
SourceRange Range = N.ASTNode.getSourceRange();
|
|
SourceLocation BeginLoc = Range.getBegin();
|
|
SourceLocation EndLoc = Lexer::getLocForEndOfToken(
|
|
Range.getEnd(), /*Offset=*/0, SrcMgr, TreeImpl->AST.getLangOpts());
|
|
if (auto *ThisExpr = N.ASTNode.get<CXXThisExpr>()) {
|
|
if (ThisExpr->isImplicit())
|
|
EndLoc = BeginLoc;
|
|
}
|
|
unsigned Begin = SrcMgr.getFileOffset(SrcMgr.getExpansionLoc(BeginLoc));
|
|
unsigned End = SrcMgr.getFileOffset(SrcMgr.getExpansionLoc(EndLoc));
|
|
return {Begin, End};
|
|
}
|
|
|
|
std::string SyntaxTree::getNodeValue(NodeId Id) const {
|
|
return TreeImpl->getNodeValue(Id);
|
|
}
|
|
|
|
std::string SyntaxTree::getNodeValue(const Node &N) const {
|
|
return TreeImpl->getNodeValue(N);
|
|
}
|
|
|
|
} // end namespace diff
|
|
} // end namespace clang
|