mirror of
https://github.com/revng/revng
synced 2026-06-21 14:07:57 +00:00
Alvise de Faveri
138 lines
4.1 KiB
C++
138 lines
4.1 KiB
C++
//
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// Copyright (c) rev.ng Srls. See LICENSE.md for details.
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//
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#include <set>
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#include <type_traits>
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#include <vector>
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#include "llvm/ADT/GraphTraits.h"
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#include "llvm/ADT/SCCIterator.h"
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#include "revng/ADT/FilteredGraphTraits.h"
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#include "revng/Support/Debug.h"
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#include "revng-c/DataLayoutAnalysis/DLATypeSystem.h"
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#include "../DLAHelpers.h"
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#include "DLAStep.h"
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using namespace llvm;
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static Logger<> LogVerbose("dla-collapse-verbose");
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static Logger<> Log("dla-collapse");
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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 InstanceNodeT = EdgeFilteredGraph<GraphNodeT, isInstanceEdge>;
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using InheritanceNodeT = EdgeFilteredGraph<GraphNodeT, isInheritanceEdge>;
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using EqualityNodeT = EdgeFilteredGraph<GraphNodeT, isEqualityEdge>;
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template<typename NodeT>
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static bool collapseSCCs(LayoutTypeSystem &TS) {
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std::set<GraphNodeT> VisitedNodes;
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using scc_t = std::vector<GraphNodeT>;
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llvm::SmallVector<scc_t, 0> ToCollapse;
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// We cannot start just from the roots because we cannot exclude that there
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// are loops without entries.
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for (const auto &Node : llvm::nodes(&TS)) {
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revng_assert(Node != nullptr);
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revng_log(LogVerbose, "## Analyzing SCCs from " << Node);
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if (VisitedNodes.count(Node)) {
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revng_log(LogVerbose, "## Was already visited");
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continue;
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}
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llvm::scc_iterator<NodeT> I = llvm::scc_begin(NodeT(Node));
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llvm::scc_iterator<NodeT> E = llvm::scc_end(NodeT(Node));
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for (const auto &SCC : llvm::make_range(I, E)) {
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revng_assert(not SCC.empty());
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if (VisitedNodes.count(SCC[0]))
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continue;
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VisitedNodes.insert(SCC.begin(), SCC.end());
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if (LogVerbose.isEnabled()) {
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revng_log(LogVerbose, "# SCC has " << SCC.size() << " elements:");
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size_t I = 0;
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for (const LTSN *N : SCC)
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revng_log(LogVerbose, " - " << I << ": " << N);
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revng_log(LogVerbose, "# SCC End");
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}
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// If the SCC is larger than just a single point we track all the nodes
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// that compose it as EqualityVisitedNodes, and we then add the SCC to the
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// set of SCC ToCollapse.
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if (SCC.size() > 1)
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ToCollapse.push_back(SCC);
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}
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}
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revng_log(LogVerbose, "## Collapsing " << ToCollapse.size() << " SCCs");
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for (scc_t &SCC : ToCollapse) {
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revng_log(LogVerbose, "# SCC with " << SCC.size() << " elements");
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TS.mergeNodes(SCC);
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}
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return ToCollapse.size();
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}
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static bool collapseInheritanceSCC(LayoutTypeSystem &TS) {
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return collapseSCCs<InheritanceNodeT>(TS);
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}
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static bool collapseEqualitySCC(LayoutTypeSystem &TS) {
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return collapseSCCs<EqualityNodeT>(TS);
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}
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bool CollapseIdentityAndInheritanceCC::runOnTypeSystem(LayoutTypeSystem &TS) {
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if (Log.isEnabled())
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TS.dumpDotOnFile("before-collapse.dot");
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revng_log(LogVerbose, "#### Merging Equality SCC: ... ");
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bool CollapsedEqual = collapseEqualitySCC(TS);
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revng_log(LogVerbose, "#### Merging Equality SCC: Done!");
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if (Log.isEnabled())
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TS.dumpDotOnFile("after-collapse-equality.dot");
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if (VerifyLog.isEnabled())
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revng_assert(TS.verifyNoEquality());
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revng_log(LogVerbose, "#### Merging Inheritance SCC: ... ");
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bool CollapsedInheritance = collapseInheritanceSCC(TS);
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revng_log(LogVerbose, "#### Merging Inheritance SCC: Done!");
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if (Log.isEnabled())
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TS.dumpDotOnFile("after-collapse-inheritance.dot");
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if (VerifyLog.isEnabled())
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revng_assert(TS.verifyInheritanceDAG());
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// The following assertion is not really necessary.
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// In principle all the rest of the pipeline should work fine without it, but
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// I think that if it's triggered something might be wrong in how we emit
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// instance edges earlier. If it's ever triggered, please double check.
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if (VerifyLog.isEnabled())
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revng_assert(TS.verifyInstanceDAG());
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revng_log(LogVerbose, "#### Merging Mixed SCC: ... ");
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bool Removed = false;
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Removed = removeInstanceBackedgesFromInheritanceLoops(TS);
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revng_log(LogVerbose, "#### Merging Mixed SCC: Done!");
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if (Log.isEnabled())
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TS.dumpDotOnFile("after-collapse.dot");
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if (VerifyLog.isEnabled())
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revng_assert(TS.verifyDAG());
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return CollapsedEqual or CollapsedInheritance or Removed;
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}
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} // end namespace dla
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