| 1 | //===- Mutations.cpp ------------------------------------------*- C++ -*-=====// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | #include "clang/Tooling/Syntax/Mutations.h" |
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| 9 | #include "clang/Basic/LLVM.h" |
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| 10 | #include "clang/Tooling/Syntax/BuildTree.h" |
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| 11 | #include "clang/Tooling/Syntax/Nodes.h" |
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| 12 | #include "clang/Tooling/Syntax/Tree.h" |
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| 13 | #include <cassert> |
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| 14 | |
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| 15 | using namespace clang; |
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| 16 | |
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| 17 | // This class has access to the internals of tree nodes. Its sole purpose is to |
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| 18 | // define helpers that allow implementing the high-level mutation operations. |
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| 19 | class syntax::MutationsImpl { |
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| 20 | public: |
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| 21 | /// Add a new node with a specified role. |
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| 22 | static void addAfter(syntax::Node *Anchor, syntax::Node *New, NodeRole Role) { |
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| 23 | assert(Anchor != nullptr); |
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| 24 | assert(Anchor->Parent != nullptr); |
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| 25 | assert(New->Parent == nullptr); |
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| 26 | assert(New->NextSibling == nullptr); |
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| 27 | assert(New->PreviousSibling == nullptr); |
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| 28 | assert(New->isDetached()); |
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| 29 | assert(Role != NodeRole::Detached); |
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| 30 | |
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| 31 | New->setRole(Role); |
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| 32 | auto *P = Anchor->getParent(); |
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| 33 | P->replaceChildRangeLowLevel(Begin: Anchor->getNextSibling(), |
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| 34 | End: Anchor->getNextSibling(), New); |
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| 35 | |
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| 36 | P->assertInvariants(); |
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| 37 | } |
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| 38 | |
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| 39 | /// Replace the node, keeping the role. |
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| 40 | static void replace(syntax::Node *Old, syntax::Node *New) { |
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| 41 | assert(Old != nullptr); |
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| 42 | assert(Old->Parent != nullptr); |
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| 43 | assert(Old->canModify()); |
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| 44 | assert(New->Parent == nullptr); |
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| 45 | assert(New->NextSibling == nullptr); |
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| 46 | assert(New->PreviousSibling == nullptr); |
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| 47 | assert(New->isDetached()); |
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| 48 | |
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| 49 | New->Role = Old->Role; |
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| 50 | auto *P = Old->getParent(); |
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| 51 | P->replaceChildRangeLowLevel(Begin: Old, End: Old->getNextSibling(), New); |
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| 52 | |
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| 53 | P->assertInvariants(); |
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| 54 | } |
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| 55 | |
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| 56 | /// Completely remove the node from its parent. |
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| 57 | static void remove(syntax::Node *N) { |
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| 58 | assert(N != nullptr); |
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| 59 | assert(N->Parent != nullptr); |
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| 60 | assert(N->canModify()); |
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| 61 | |
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| 62 | auto *P = N->getParent(); |
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| 63 | P->replaceChildRangeLowLevel(Begin: N, End: N->getNextSibling(), |
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| 64 | /*New=*/nullptr); |
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| 65 | |
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| 66 | P->assertInvariants(); |
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| 67 | N->assertInvariants(); |
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| 68 | } |
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| 69 | }; |
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| 70 | |
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| 71 | void syntax::removeStatement(syntax::Arena &A, TokenBufferTokenManager &TBTM, |
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| 72 | syntax::Statement *S) { |
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| 73 | assert(S); |
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| 74 | assert(S->canModify()); |
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| 75 | |
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| 76 | if (isa<CompoundStatement>(Val: S->getParent())) { |
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| 77 | // A child of CompoundStatement can just be safely removed. |
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| 78 | MutationsImpl::remove(N: S); |
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| 79 | return; |
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| 80 | } |
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| 81 | // For the rest, we have to replace with an empty statement. |
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| 82 | if (isa<EmptyStatement>(Val: S)) |
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| 83 | return; // already an empty statement, nothing to do. |
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| 84 | |
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| 85 | MutationsImpl::replace(Old: S, New: createEmptyStatement(A, TBTM)); |
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| 86 | } |
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| 87 | |
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