6024e5c395
clang 20.0.0 (based on r547379) from build 12806354. Bug: http://b/379133546 Test: N/A Change-Id: I2eb8938af55d809de674be63cb30cf27e801862b Upstream-Commit: ad834e67b1105d15ef907f6255d4c96e8e733f57
128 lines
4.0 KiB
C++
128 lines
4.0 KiB
C++
//===- ASTDiff.h - AST differencing API -----------------------*- C++ -*- -===//
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//
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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 specifies an interface that can be used to compare C++ syntax
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// trees.
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//
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// We use the gumtree algorithm which combines a heuristic top-down search that
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// is able to match large subtrees that are equivalent, with an optimal
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// algorithm to match small subtrees.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_TOOLING_ASTDIFF_ASTDIFF_H
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#define LLVM_CLANG_TOOLING_ASTDIFF_ASTDIFF_H
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#include "clang/Tooling/ASTDiff/ASTDiffInternal.h"
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#include <optional>
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namespace clang {
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namespace diff {
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enum ChangeKind {
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None,
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Delete, // (Src): delete node Src.
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Update, // (Src, Dst): update the value of node Src to match Dst.
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Insert, // (Src, Dst, Pos): insert Src as child of Dst at offset Pos.
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Move, // (Src, Dst, Pos): move Src to be a child of Dst at offset Pos.
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UpdateMove // Same as Move plus Update.
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};
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/// Represents a Clang AST node, alongside some additional information.
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struct Node {
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NodeId Parent, LeftMostDescendant, RightMostDescendant;
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int Depth, Height, Shift = 0;
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DynTypedNode ASTNode;
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SmallVector<NodeId, 4> Children;
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ChangeKind Change = None;
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ASTNodeKind getType() const;
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StringRef getTypeLabel() const;
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bool isLeaf() const { return Children.empty(); }
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std::optional<StringRef> getIdentifier() const;
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std::optional<std::string> getQualifiedIdentifier() const;
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};
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/// SyntaxTree objects represent subtrees of the AST.
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/// They can be constructed from any Decl or Stmt.
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class SyntaxTree {
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public:
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/// Constructs a tree from a translation unit.
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SyntaxTree(ASTContext &AST);
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/// Constructs a tree from any AST node.
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template <class T>
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SyntaxTree(T *Node, ASTContext &AST)
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: TreeImpl(std::make_unique<Impl>(this, Node, AST)) {}
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SyntaxTree(SyntaxTree &&Other) = default;
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~SyntaxTree();
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const ASTContext &getASTContext() const;
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StringRef getFilename() const;
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int getSize() const;
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NodeId getRootId() const;
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using PreorderIterator = NodeId;
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PreorderIterator begin() const;
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PreorderIterator end() const;
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const Node &getNode(NodeId Id) const;
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int findPositionInParent(NodeId Id) const;
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// Returns the starting and ending offset of the node in its source file.
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std::pair<unsigned, unsigned> getSourceRangeOffsets(const Node &N) const;
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/// Serialize the node attributes to a string representation. This should
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/// uniquely distinguish nodes of the same kind. Note that this function just
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/// returns a representation of the node value, not considering descendants.
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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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class Impl;
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std::unique_ptr<Impl> TreeImpl;
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};
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struct ComparisonOptions {
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/// During top-down matching, only consider nodes of at least this height.
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int MinHeight = 2;
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/// During bottom-up matching, match only nodes with at least this value as
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/// the ratio of their common descendants.
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double MinSimilarity = 0.5;
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/// Whenever two subtrees are matched in the bottom-up phase, the optimal
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/// mapping is computed, unless the size of either subtrees exceeds this.
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int MaxSize = 100;
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bool StopAfterTopDown = false;
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/// Returns false if the nodes should never be matched.
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bool isMatchingAllowed(const Node &N1, const Node &N2) const {
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return N1.getType().isSame(N2.getType());
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}
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};
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class ASTDiff {
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public:
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ASTDiff(SyntaxTree &Src, SyntaxTree &Dst, const ComparisonOptions &Options);
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~ASTDiff();
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// Returns the ID of the node that is mapped to the given node in SourceTree.
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NodeId getMapped(const SyntaxTree &SourceTree, NodeId Id) const;
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class Impl;
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private:
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std::unique_ptr<Impl> DiffImpl;
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};
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} // end namespace diff
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} // end namespace clang
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#endif
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