mirror of
https://github.com/revng/revng
synced 2026-06-21 14:07:57 +00:00
Alessandro Di Federico
67 lines
2.1 KiB
C++
67 lines
2.1 KiB
C++
//
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// This file is distributed under the MIT License. See LICENSE.md for details.
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//
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#include "llvm/ADT/DepthFirstIterator.h"
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#include "revng/DataLayoutAnalysis/DLATypeSystem.h"
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#include "DLAStep.h"
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using namespace llvm;
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static Logger Log("dla-merge-pointer-nodes");
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namespace dla {
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using LTSN = LayoutTypeSystemNode;
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using GraphNodeT = LTSN *;
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using PointerGraphNodeT = EdgeFilteredGraph<GraphNodeT, isPointerEdge>;
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using InversePointerGraphNodeT = llvm::Inverse<PointerGraphNodeT>;
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bool MergePointerNodes::runOnTypeSystem(LayoutTypeSystem &TS) {
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bool Changed = false;
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for (LTSN *Node : llvm::nodes(&TS)) {
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revng_assert(Node != nullptr);
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revng_log(Log, "# Starting from Node: " << Node->ID);
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for (auto *Node : llvm::depth_first(InversePointerGraphNodeT(Node))) {
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if (isPointerRoot(Node))
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continue;
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std::vector<LTSN *> ToMerge;
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// Look at the pointers to Node. The all have to be merged together.
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// Doing so does not invalidate the depth_first iterator we're holding,
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// because that points to Node, and the iterator only looks at
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// predecessors of Node when it's incremented. So until then we can
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// change the predecessors of Node without problems.
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for (LTSN *PointerToMerge :
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llvm::children<InversePointerGraphNodeT>(Node)) {
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revng_log(Log, "#### PointerToMerge: " << PointerToMerge->ID);
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revng_assert(PointerToMerge != Node);
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revng_assert(PointerToMerge->Successors.size() == 1);
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revng_assert(ToMerge.empty()
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or ToMerge[0]->Size == PointerToMerge->Size);
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ToMerge.push_back(PointerToMerge);
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}
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if (ToMerge.size() < 2)
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continue;
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Changed = true;
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// This does note invalidate our iteration on llvm::nodes, since the
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// underlying container for nodes is a std::set, and the iterator that is
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// being held on it points to Node, not to any of the nodes in ToMerge,
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// so erasing the nodes in ToMerge never invalidats the iterator to Node
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TS.mergeNodes(ToMerge);
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}
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}
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return Changed;
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}
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} // end namespace dla
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