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1732 lines
54 KiB
1732 lines
54 KiB
//===--- RDFGraph.cpp -----------------------------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// Target-independent, SSA-based data flow graph for register data flow (RDF).
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//
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#include "RDFGraph.h"
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#include "llvm/ADT/SetVector.h"
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#include "llvm/CodeGen/MachineBasicBlock.h"
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#include "llvm/CodeGen/MachineDominanceFrontier.h"
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#include "llvm/CodeGen/MachineDominators.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/CodeGen/MachineRegisterInfo.h"
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#include "llvm/Target/TargetInstrInfo.h"
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#include "llvm/Target/TargetRegisterInfo.h"
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using namespace llvm;
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using namespace rdf;
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// Printing functions. Have them here first, so that the rest of the code
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// can use them.
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namespace llvm {
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namespace rdf {
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template<>
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raw_ostream &operator<< (raw_ostream &OS, const Print<RegisterRef> &P) {
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auto &TRI = P.G.getTRI();
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if (P.Obj.Reg > 0 && P.Obj.Reg < TRI.getNumRegs())
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OS << TRI.getName(P.Obj.Reg);
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else
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OS << '#' << P.Obj.Reg;
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if (P.Obj.Sub > 0) {
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OS << ':';
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if (P.Obj.Sub < TRI.getNumSubRegIndices())
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OS << TRI.getSubRegIndexName(P.Obj.Sub);
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else
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OS << '#' << P.Obj.Sub;
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}
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return OS;
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}
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template<>
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raw_ostream &operator<< (raw_ostream &OS, const Print<NodeId> &P) {
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auto NA = P.G.addr<NodeBase*>(P.Obj);
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uint16_t Attrs = NA.Addr->getAttrs();
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uint16_t Kind = NodeAttrs::kind(Attrs);
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uint16_t Flags = NodeAttrs::flags(Attrs);
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switch (NodeAttrs::type(Attrs)) {
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case NodeAttrs::Code:
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switch (Kind) {
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case NodeAttrs::Func: OS << 'f'; break;
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case NodeAttrs::Block: OS << 'b'; break;
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case NodeAttrs::Stmt: OS << 's'; break;
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case NodeAttrs::Phi: OS << 'p'; break;
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default: OS << "c?"; break;
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}
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break;
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case NodeAttrs::Ref:
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if (Flags & NodeAttrs::Preserving)
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OS << '+';
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if (Flags & NodeAttrs::Clobbering)
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OS << '~';
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switch (Kind) {
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case NodeAttrs::Use: OS << 'u'; break;
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case NodeAttrs::Def: OS << 'd'; break;
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case NodeAttrs::Block: OS << 'b'; break;
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default: OS << "r?"; break;
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}
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break;
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default:
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OS << '?';
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break;
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}
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OS << P.Obj;
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if (Flags & NodeAttrs::Shadow)
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OS << '"';
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return OS;
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}
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namespace {
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void printRefHeader(raw_ostream &OS, const NodeAddr<RefNode*> RA,
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const DataFlowGraph &G) {
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OS << Print<NodeId>(RA.Id, G) << '<'
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<< Print<RegisterRef>(RA.Addr->getRegRef(), G) << '>';
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if (RA.Addr->getFlags() & NodeAttrs::Fixed)
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OS << '!';
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}
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}
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template<>
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raw_ostream &operator<< (raw_ostream &OS, const Print<NodeAddr<DefNode*>> &P) {
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printRefHeader(OS, P.Obj, P.G);
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OS << '(';
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if (NodeId N = P.Obj.Addr->getReachingDef())
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OS << Print<NodeId>(N, P.G);
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OS << ',';
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if (NodeId N = P.Obj.Addr->getReachedDef())
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OS << Print<NodeId>(N, P.G);
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OS << ',';
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if (NodeId N = P.Obj.Addr->getReachedUse())
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OS << Print<NodeId>(N, P.G);
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OS << "):";
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if (NodeId N = P.Obj.Addr->getSibling())
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OS << Print<NodeId>(N, P.G);
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return OS;
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}
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template<>
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raw_ostream &operator<< (raw_ostream &OS, const Print<NodeAddr<UseNode*>> &P) {
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printRefHeader(OS, P.Obj, P.G);
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OS << '(';
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if (NodeId N = P.Obj.Addr->getReachingDef())
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OS << Print<NodeId>(N, P.G);
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OS << "):";
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if (NodeId N = P.Obj.Addr->getSibling())
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OS << Print<NodeId>(N, P.G);
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return OS;
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}
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template<>
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raw_ostream &operator<< (raw_ostream &OS,
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const Print<NodeAddr<PhiUseNode*>> &P) {
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printRefHeader(OS, P.Obj, P.G);
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OS << '(';
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if (NodeId N = P.Obj.Addr->getReachingDef())
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OS << Print<NodeId>(N, P.G);
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OS << ',';
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if (NodeId N = P.Obj.Addr->getPredecessor())
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OS << Print<NodeId>(N, P.G);
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OS << "):";
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if (NodeId N = P.Obj.Addr->getSibling())
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OS << Print<NodeId>(N, P.G);
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return OS;
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}
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template<>
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raw_ostream &operator<< (raw_ostream &OS, const Print<NodeAddr<RefNode*>> &P) {
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switch (P.Obj.Addr->getKind()) {
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case NodeAttrs::Def:
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OS << PrintNode<DefNode*>(P.Obj, P.G);
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break;
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case NodeAttrs::Use:
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if (P.Obj.Addr->getFlags() & NodeAttrs::PhiRef)
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OS << PrintNode<PhiUseNode*>(P.Obj, P.G);
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else
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OS << PrintNode<UseNode*>(P.Obj, P.G);
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break;
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}
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return OS;
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}
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template<>
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raw_ostream &operator<< (raw_ostream &OS, const Print<NodeList> &P) {
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unsigned N = P.Obj.size();
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for (auto I : P.Obj) {
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OS << Print<NodeId>(I.Id, P.G);
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if (--N)
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OS << ' ';
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}
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return OS;
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}
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template<>
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raw_ostream &operator<< (raw_ostream &OS, const Print<NodeSet> &P) {
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unsigned N = P.Obj.size();
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for (auto I : P.Obj) {
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OS << Print<NodeId>(I, P.G);
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if (--N)
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OS << ' ';
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}
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return OS;
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}
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namespace {
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template <typename T>
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struct PrintListV {
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PrintListV(const NodeList &L, const DataFlowGraph &G) : List(L), G(G) {}
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typedef T Type;
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const NodeList &List;
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const DataFlowGraph &G;
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};
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template <typename T>
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raw_ostream &operator<< (raw_ostream &OS, const PrintListV<T> &P) {
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unsigned N = P.List.size();
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for (NodeAddr<T> A : P.List) {
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OS << PrintNode<T>(A, P.G);
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if (--N)
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OS << ", ";
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}
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return OS;
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}
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}
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template<>
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raw_ostream &operator<< (raw_ostream &OS, const Print<NodeAddr<PhiNode*>> &P) {
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OS << Print<NodeId>(P.Obj.Id, P.G) << ": phi ["
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<< PrintListV<RefNode*>(P.Obj.Addr->members(P.G), P.G) << ']';
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return OS;
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}
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template<>
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raw_ostream &operator<< (raw_ostream &OS,
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const Print<NodeAddr<StmtNode*>> &P) {
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unsigned Opc = P.Obj.Addr->getCode()->getOpcode();
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OS << Print<NodeId>(P.Obj.Id, P.G) << ": " << P.G.getTII().getName(Opc)
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<< " [" << PrintListV<RefNode*>(P.Obj.Addr->members(P.G), P.G) << ']';
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return OS;
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}
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template<>
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raw_ostream &operator<< (raw_ostream &OS,
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const Print<NodeAddr<InstrNode*>> &P) {
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switch (P.Obj.Addr->getKind()) {
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case NodeAttrs::Phi:
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OS << PrintNode<PhiNode*>(P.Obj, P.G);
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break;
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case NodeAttrs::Stmt:
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OS << PrintNode<StmtNode*>(P.Obj, P.G);
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break;
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default:
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OS << "instr? " << Print<NodeId>(P.Obj.Id, P.G);
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break;
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}
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return OS;
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}
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template<>
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raw_ostream &operator<< (raw_ostream &OS,
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const Print<NodeAddr<BlockNode*>> &P) {
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auto *BB = P.Obj.Addr->getCode();
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unsigned NP = BB->pred_size();
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std::vector<int> Ns;
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auto PrintBBs = [&OS,&P] (std::vector<int> Ns) -> void {
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unsigned N = Ns.size();
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for (auto I : Ns) {
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OS << "BB#" << I;
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if (--N)
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OS << ", ";
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}
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};
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OS << Print<NodeId>(P.Obj.Id, P.G) << ": === BB#" << BB->getNumber()
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<< " === preds(" << NP << "): ";
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for (auto I : BB->predecessors())
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Ns.push_back(I->getNumber());
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PrintBBs(Ns);
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unsigned NS = BB->succ_size();
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OS << " succs(" << NS << "): ";
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Ns.clear();
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for (auto I : BB->successors())
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Ns.push_back(I->getNumber());
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PrintBBs(Ns);
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OS << '\n';
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for (auto I : P.Obj.Addr->members(P.G))
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OS << PrintNode<InstrNode*>(I, P.G) << '\n';
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return OS;
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}
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template<>
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raw_ostream &operator<< (raw_ostream &OS,
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const Print<NodeAddr<FuncNode*>> &P) {
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OS << "DFG dump:[\n" << Print<NodeId>(P.Obj.Id, P.G) << ": Function: "
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<< P.Obj.Addr->getCode()->getName() << '\n';
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for (auto I : P.Obj.Addr->members(P.G))
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OS << PrintNode<BlockNode*>(I, P.G) << '\n';
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OS << "]\n";
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return OS;
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}
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template<>
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raw_ostream &operator<< (raw_ostream &OS, const Print<RegisterSet> &P) {
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OS << '{';
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for (auto I : P.Obj)
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OS << ' ' << Print<RegisterRef>(I, P.G);
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OS << " }";
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return OS;
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}
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template<>
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raw_ostream &operator<< (raw_ostream &OS,
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const Print<DataFlowGraph::DefStack> &P) {
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for (auto I = P.Obj.top(), E = P.Obj.bottom(); I != E; ) {
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OS << Print<NodeId>(I->Id, P.G)
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<< '<' << Print<RegisterRef>(I->Addr->getRegRef(), P.G) << '>';
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I.down();
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if (I != E)
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OS << ' ';
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}
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return OS;
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}
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} // namespace rdf
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} // namespace llvm
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// Node allocation functions.
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//
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// Node allocator is like a slab memory allocator: it allocates blocks of
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// memory in sizes that are multiples of the size of a node. Each block has
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// the same size. Nodes are allocated from the currently active block, and
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// when it becomes full, a new one is created.
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// There is a mapping scheme between node id and its location in a block,
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// and within that block is described in the header file.
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//
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void NodeAllocator::startNewBlock() {
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void *T = MemPool.Allocate(NodesPerBlock*NodeMemSize, NodeMemSize);
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char *P = static_cast<char*>(T);
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Blocks.push_back(P);
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// Check if the block index is still within the allowed range, i.e. less
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// than 2^N, where N is the number of bits in NodeId for the block index.
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// BitsPerIndex is the number of bits per node index.
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assert((Blocks.size() < ((size_t)1 << (8*sizeof(NodeId)-BitsPerIndex))) &&
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"Out of bits for block index");
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ActiveEnd = P;
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}
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bool NodeAllocator::needNewBlock() {
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if (Blocks.empty())
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return true;
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char *ActiveBegin = Blocks.back();
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uint32_t Index = (ActiveEnd-ActiveBegin)/NodeMemSize;
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return Index >= NodesPerBlock;
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}
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NodeAddr<NodeBase*> NodeAllocator::New() {
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if (needNewBlock())
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startNewBlock();
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uint32_t ActiveB = Blocks.size()-1;
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uint32_t Index = (ActiveEnd - Blocks[ActiveB])/NodeMemSize;
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NodeAddr<NodeBase*> NA = { reinterpret_cast<NodeBase*>(ActiveEnd),
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makeId(ActiveB, Index) };
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ActiveEnd += NodeMemSize;
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return NA;
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}
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NodeId NodeAllocator::id(const NodeBase *P) const {
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uintptr_t A = reinterpret_cast<uintptr_t>(P);
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for (unsigned i = 0, n = Blocks.size(); i != n; ++i) {
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uintptr_t B = reinterpret_cast<uintptr_t>(Blocks[i]);
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if (A < B || A >= B + NodesPerBlock*NodeMemSize)
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continue;
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uint32_t Idx = (A-B)/NodeMemSize;
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return makeId(i, Idx);
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}
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llvm_unreachable("Invalid node address");
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}
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void NodeAllocator::clear() {
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MemPool.Reset();
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Blocks.clear();
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ActiveEnd = nullptr;
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}
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// Insert node NA after "this" in the circular chain.
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void NodeBase::append(NodeAddr<NodeBase*> NA) {
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NodeId Nx = Next;
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// If NA is already "next", do nothing.
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if (Next != NA.Id) {
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Next = NA.Id;
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NA.Addr->Next = Nx;
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}
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}
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// Fundamental node manipulator functions.
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// Obtain the register reference from a reference node.
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RegisterRef RefNode::getRegRef() const {
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assert(NodeAttrs::type(Attrs) == NodeAttrs::Ref);
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if (NodeAttrs::flags(Attrs) & NodeAttrs::PhiRef)
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return Ref.RR;
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assert(Ref.Op != nullptr);
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return { Ref.Op->getReg(), Ref.Op->getSubReg() };
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}
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// Set the register reference in the reference node directly (for references
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// in phi nodes).
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void RefNode::setRegRef(RegisterRef RR) {
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assert(NodeAttrs::type(Attrs) == NodeAttrs::Ref);
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assert(NodeAttrs::flags(Attrs) & NodeAttrs::PhiRef);
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Ref.RR = RR;
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}
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// Set the register reference in the reference node based on a machine
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// operand (for references in statement nodes).
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void RefNode::setRegRef(MachineOperand *Op) {
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assert(NodeAttrs::type(Attrs) == NodeAttrs::Ref);
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assert(!(NodeAttrs::flags(Attrs) & NodeAttrs::PhiRef));
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Ref.Op = Op;
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}
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// Get the owner of a given reference node.
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NodeAddr<NodeBase*> RefNode::getOwner(const DataFlowGraph &G) {
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NodeAddr<NodeBase*> NA = G.addr<NodeBase*>(getNext());
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while (NA.Addr != this) {
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if (NA.Addr->getType() == NodeAttrs::Code)
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return NA;
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NA = G.addr<NodeBase*>(NA.Addr->getNext());
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}
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llvm_unreachable("No owner in circular list");
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}
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// Connect the def node to the reaching def node.
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void DefNode::linkToDef(NodeId Self, NodeAddr<DefNode*> DA) {
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Ref.RD = DA.Id;
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Ref.Sib = DA.Addr->getReachedDef();
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DA.Addr->setReachedDef(Self);
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}
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// Connect the use node to the reaching def node.
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void UseNode::linkToDef(NodeId Self, NodeAddr<DefNode*> DA) {
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Ref.RD = DA.Id;
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Ref.Sib = DA.Addr->getReachedUse();
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DA.Addr->setReachedUse(Self);
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}
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|
|
// Get the first member of the code node.
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NodeAddr<NodeBase*> CodeNode::getFirstMember(const DataFlowGraph &G) const {
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if (Code.FirstM == 0)
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return NodeAddr<NodeBase*>();
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return G.addr<NodeBase*>(Code.FirstM);
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}
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|
|
// Get the last member of the code node.
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NodeAddr<NodeBase*> CodeNode::getLastMember(const DataFlowGraph &G) const {
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if (Code.LastM == 0)
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return NodeAddr<NodeBase*>();
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return G.addr<NodeBase*>(Code.LastM);
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}
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|
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// Add node NA at the end of the member list of the given code node.
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void CodeNode::addMember(NodeAddr<NodeBase*> NA, const DataFlowGraph &G) {
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auto ML = getLastMember(G);
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if (ML.Id != 0) {
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ML.Addr->append(NA);
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} else {
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Code.FirstM = NA.Id;
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NodeId Self = G.id(this);
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NA.Addr->setNext(Self);
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}
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Code.LastM = NA.Id;
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}
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|
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// Add node NA after member node MA in the given code node.
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void CodeNode::addMemberAfter(NodeAddr<NodeBase*> MA, NodeAddr<NodeBase*> NA,
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const DataFlowGraph &G) {
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MA.Addr->append(NA);
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if (Code.LastM == MA.Id)
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Code.LastM = NA.Id;
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}
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|
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// Remove member node NA from the given code node.
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void CodeNode::removeMember(NodeAddr<NodeBase*> NA, const DataFlowGraph &G) {
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auto MA = getFirstMember(G);
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assert(MA.Id != 0);
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|
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// Special handling if the member to remove is the first member.
|
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if (MA.Id == NA.Id) {
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if (Code.LastM == MA.Id) {
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// If it is the only member, set both first and last to 0.
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Code.FirstM = Code.LastM = 0;
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} else {
|
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// Otherwise, advance the first member.
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Code.FirstM = MA.Addr->getNext();
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}
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return;
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}
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|
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while (MA.Addr != this) {
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NodeId MX = MA.Addr->getNext();
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if (MX == NA.Id) {
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MA.Addr->setNext(NA.Addr->getNext());
|
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// If the member to remove happens to be the last one, update the
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// LastM indicator.
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if (Code.LastM == NA.Id)
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Code.LastM = MA.Id;
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return;
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}
|
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MA = G.addr<NodeBase*>(MX);
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}
|
|
llvm_unreachable("No such member");
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|
}
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|
|
// Return the list of all members of the code node.
|
|
NodeList CodeNode::members(const DataFlowGraph &G) const {
|
|
static auto True = [] (NodeAddr<NodeBase*>) -> bool { return true; };
|
|
return members_if(True, G);
|
|
}
|
|
|
|
// Return the owner of the given instr node.
|
|
NodeAddr<NodeBase*> InstrNode::getOwner(const DataFlowGraph &G) {
|
|
NodeAddr<NodeBase*> NA = G.addr<NodeBase*>(getNext());
|
|
|
|
while (NA.Addr != this) {
|
|
assert(NA.Addr->getType() == NodeAttrs::Code);
|
|
if (NA.Addr->getKind() == NodeAttrs::Block)
|
|
return NA;
|
|
NA = G.addr<NodeBase*>(NA.Addr->getNext());
|
|
}
|
|
llvm_unreachable("No owner in circular list");
|
|
}
|
|
|
|
// Add the phi node PA to the given block node.
|
|
void BlockNode::addPhi(NodeAddr<PhiNode*> PA, const DataFlowGraph &G) {
|
|
auto M = getFirstMember(G);
|
|
if (M.Id == 0) {
|
|
addMember(PA, G);
|
|
return;
|
|
}
|
|
|
|
assert(M.Addr->getType() == NodeAttrs::Code);
|
|
if (M.Addr->getKind() == NodeAttrs::Stmt) {
|
|
// If the first member of the block is a statement, insert the phi as
|
|
// the first member.
|
|
Code.FirstM = PA.Id;
|
|
PA.Addr->setNext(M.Id);
|
|
} else {
|
|
// If the first member is a phi, find the last phi, and append PA to it.
|
|
assert(M.Addr->getKind() == NodeAttrs::Phi);
|
|
NodeAddr<NodeBase*> MN = M;
|
|
do {
|
|
M = MN;
|
|
MN = G.addr<NodeBase*>(M.Addr->getNext());
|
|
assert(MN.Addr->getType() == NodeAttrs::Code);
|
|
} while (MN.Addr->getKind() == NodeAttrs::Phi);
|
|
|
|
// M is the last phi.
|
|
addMemberAfter(M, PA, G);
|
|
}
|
|
}
|
|
|
|
// Find the block node corresponding to the machine basic block BB in the
|
|
// given func node.
|
|
NodeAddr<BlockNode*> FuncNode::findBlock(const MachineBasicBlock *BB,
|
|
const DataFlowGraph &G) const {
|
|
auto EqBB = [BB] (NodeAddr<NodeBase*> NA) -> bool {
|
|
return NodeAddr<BlockNode*>(NA).Addr->getCode() == BB;
|
|
};
|
|
NodeList Ms = members_if(EqBB, G);
|
|
if (!Ms.empty())
|
|
return Ms[0];
|
|
return NodeAddr<BlockNode*>();
|
|
}
|
|
|
|
// Get the block node for the entry block in the given function.
|
|
NodeAddr<BlockNode*> FuncNode::getEntryBlock(const DataFlowGraph &G) {
|
|
MachineBasicBlock *EntryB = &getCode()->front();
|
|
return findBlock(EntryB, G);
|
|
}
|
|
|
|
|
|
// Register aliasing information.
|
|
//
|
|
// In theory, the lane information could be used to determine register
|
|
// covering (and aliasing), but depending on the sub-register structure,
|
|
// the lane mask information may be missing. The covering information
|
|
// must be available for this framework to work, so relying solely on
|
|
// the lane data is not sufficient.
|
|
|
|
// Determine whether RA covers RB.
|
|
bool RegisterAliasInfo::covers(RegisterRef RA, RegisterRef RB) const {
|
|
if (RA == RB)
|
|
return true;
|
|
if (TargetRegisterInfo::isVirtualRegister(RA.Reg)) {
|
|
assert(TargetRegisterInfo::isVirtualRegister(RB.Reg));
|
|
if (RA.Reg != RB.Reg)
|
|
return false;
|
|
if (RA.Sub == 0)
|
|
return true;
|
|
return TRI.composeSubRegIndices(RA.Sub, RB.Sub) == RA.Sub;
|
|
}
|
|
|
|
assert(TargetRegisterInfo::isPhysicalRegister(RA.Reg) &&
|
|
TargetRegisterInfo::isPhysicalRegister(RB.Reg));
|
|
unsigned A = RA.Sub != 0 ? TRI.getSubReg(RA.Reg, RA.Sub) : RA.Reg;
|
|
unsigned B = RB.Sub != 0 ? TRI.getSubReg(RB.Reg, RB.Sub) : RB.Reg;
|
|
return TRI.isSubRegister(A, B);
|
|
}
|
|
|
|
// Determine whether RR is covered by the set of references RRs.
|
|
bool RegisterAliasInfo::covers(const RegisterSet &RRs, RegisterRef RR) const {
|
|
if (RRs.count(RR))
|
|
return true;
|
|
|
|
// For virtual registers, we cannot accurately determine covering based
|
|
// on subregisters. If RR itself is not present in RRs, but it has a sub-
|
|
// register reference, check for the super-register alone. Otherwise,
|
|
// assume non-covering.
|
|
if (TargetRegisterInfo::isVirtualRegister(RR.Reg)) {
|
|
if (RR.Sub != 0)
|
|
return RRs.count({RR.Reg, 0});
|
|
return false;
|
|
}
|
|
|
|
// If any super-register of RR is present, then RR is covered.
|
|
unsigned Reg = RR.Sub == 0 ? RR.Reg : TRI.getSubReg(RR.Reg, RR.Sub);
|
|
for (MCSuperRegIterator SR(Reg, &TRI); SR.isValid(); ++SR)
|
|
if (RRs.count({*SR, 0}))
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
// Get the list of references aliased to RR.
|
|
std::vector<RegisterRef> RegisterAliasInfo::getAliasSet(RegisterRef RR) const {
|
|
// Do not include RR in the alias set. For virtual registers return an
|
|
// empty set.
|
|
std::vector<RegisterRef> AS;
|
|
if (TargetRegisterInfo::isVirtualRegister(RR.Reg))
|
|
return AS;
|
|
assert(TargetRegisterInfo::isPhysicalRegister(RR.Reg));
|
|
unsigned R = RR.Reg;
|
|
if (RR.Sub)
|
|
R = TRI.getSubReg(RR.Reg, RR.Sub);
|
|
|
|
for (MCRegAliasIterator AI(R, &TRI, false); AI.isValid(); ++AI)
|
|
AS.push_back(RegisterRef({*AI, 0}));
|
|
return AS;
|
|
}
|
|
|
|
// Check whether RA and RB are aliased.
|
|
bool RegisterAliasInfo::alias(RegisterRef RA, RegisterRef RB) const {
|
|
bool VirtA = TargetRegisterInfo::isVirtualRegister(RA.Reg);
|
|
bool VirtB = TargetRegisterInfo::isVirtualRegister(RB.Reg);
|
|
bool PhysA = TargetRegisterInfo::isPhysicalRegister(RA.Reg);
|
|
bool PhysB = TargetRegisterInfo::isPhysicalRegister(RB.Reg);
|
|
|
|
if (VirtA != VirtB)
|
|
return false;
|
|
|
|
if (VirtA) {
|
|
if (RA.Reg != RB.Reg)
|
|
return false;
|
|
// RA and RB refer to the same register. If any of them refer to the
|
|
// whole register, they must be aliased.
|
|
if (RA.Sub == 0 || RB.Sub == 0)
|
|
return true;
|
|
unsigned SA = TRI.getSubRegIdxSize(RA.Sub);
|
|
unsigned OA = TRI.getSubRegIdxOffset(RA.Sub);
|
|
unsigned SB = TRI.getSubRegIdxSize(RB.Sub);
|
|
unsigned OB = TRI.getSubRegIdxOffset(RB.Sub);
|
|
if (OA <= OB && OA+SA > OB)
|
|
return true;
|
|
if (OB <= OA && OB+SB > OA)
|
|
return true;
|
|
return false;
|
|
}
|
|
|
|
assert(PhysA && PhysB);
|
|
(void)PhysA, (void)PhysB;
|
|
unsigned A = RA.Sub ? TRI.getSubReg(RA.Reg, RA.Sub) : RA.Reg;
|
|
unsigned B = RB.Sub ? TRI.getSubReg(RB.Reg, RB.Sub) : RB.Reg;
|
|
for (MCRegAliasIterator I(A, &TRI, true); I.isValid(); ++I)
|
|
if (B == *I)
|
|
return true;
|
|
return false;
|
|
}
|
|
|
|
|
|
// Target operand information.
|
|
//
|
|
|
|
// For a given instruction, check if there are any bits of RR that can remain
|
|
// unchanged across this def.
|
|
bool TargetOperandInfo::isPreserving(const MachineInstr &In, unsigned OpNum)
|
|
const {
|
|
return TII.isPredicated(In);
|
|
}
|
|
|
|
// Check if the definition of RR produces an unspecified value.
|
|
bool TargetOperandInfo::isClobbering(const MachineInstr &In, unsigned OpNum)
|
|
const {
|
|
if (In.isCall())
|
|
if (In.getOperand(OpNum).isImplicit())
|
|
return true;
|
|
return false;
|
|
}
|
|
|
|
// Check if the given instruction specifically requires
|
|
bool TargetOperandInfo::isFixedReg(const MachineInstr &In, unsigned OpNum)
|
|
const {
|
|
if (In.isCall() || In.isReturn() || In.isInlineAsm())
|
|
return true;
|
|
// Check for a tail call.
|
|
if (In.isBranch())
|
|
for (auto &O : In.operands())
|
|
if (O.isGlobal() || O.isSymbol())
|
|
return true;
|
|
|
|
const MCInstrDesc &D = In.getDesc();
|
|
if (!D.getImplicitDefs() && !D.getImplicitUses())
|
|
return false;
|
|
const MachineOperand &Op = In.getOperand(OpNum);
|
|
// If there is a sub-register, treat the operand as non-fixed. Currently,
|
|
// fixed registers are those that are listed in the descriptor as implicit
|
|
// uses or defs, and those lists do not allow sub-registers.
|
|
if (Op.getSubReg() != 0)
|
|
return false;
|
|
unsigned Reg = Op.getReg();
|
|
const MCPhysReg *ImpR = Op.isDef() ? D.getImplicitDefs()
|
|
: D.getImplicitUses();
|
|
if (!ImpR)
|
|
return false;
|
|
while (*ImpR)
|
|
if (*ImpR++ == Reg)
|
|
return true;
|
|
return false;
|
|
}
|
|
|
|
|
|
//
|
|
// The data flow graph construction.
|
|
//
|
|
|
|
DataFlowGraph::DataFlowGraph(MachineFunction &mf, const TargetInstrInfo &tii,
|
|
const TargetRegisterInfo &tri, const MachineDominatorTree &mdt,
|
|
const MachineDominanceFrontier &mdf, const RegisterAliasInfo &rai,
|
|
const TargetOperandInfo &toi)
|
|
: TimeG("rdf"), MF(mf), TII(tii), TRI(tri), MDT(mdt), MDF(mdf), RAI(rai),
|
|
TOI(toi) {
|
|
}
|
|
|
|
|
|
// The implementation of the definition stack.
|
|
// Each register reference has its own definition stack. In particular,
|
|
// for a register references "Reg" and "Reg:subreg" will each have their
|
|
// own definition stacks.
|
|
|
|
// Construct a stack iterator.
|
|
DataFlowGraph::DefStack::Iterator::Iterator(const DataFlowGraph::DefStack &S,
|
|
bool Top) : DS(S) {
|
|
if (!Top) {
|
|
// Initialize to bottom.
|
|
Pos = 0;
|
|
return;
|
|
}
|
|
// Initialize to the top, i.e. top-most non-delimiter (or 0, if empty).
|
|
Pos = DS.Stack.size();
|
|
while (Pos > 0 && DS.isDelimiter(DS.Stack[Pos-1]))
|
|
Pos--;
|
|
}
|
|
|
|
// Return the size of the stack, including block delimiters.
|
|
unsigned DataFlowGraph::DefStack::size() const {
|
|
unsigned S = 0;
|
|
for (auto I = top(), E = bottom(); I != E; I.down())
|
|
S++;
|
|
return S;
|
|
}
|
|
|
|
// Remove the top entry from the stack. Remove all intervening delimiters
|
|
// so that after this, the stack is either empty, or the top of the stack
|
|
// is a non-delimiter.
|
|
void DataFlowGraph::DefStack::pop() {
|
|
assert(!empty());
|
|
unsigned P = nextDown(Stack.size());
|
|
Stack.resize(P);
|
|
}
|
|
|
|
// Push a delimiter for block node N on the stack.
|
|
void DataFlowGraph::DefStack::start_block(NodeId N) {
|
|
assert(N != 0);
|
|
Stack.push_back(NodeAddr<DefNode*>(nullptr, N));
|
|
}
|
|
|
|
// Remove all nodes from the top of the stack, until the delimited for
|
|
// block node N is encountered. Remove the delimiter as well. In effect,
|
|
// this will remove from the stack all definitions from block N.
|
|
void DataFlowGraph::DefStack::clear_block(NodeId N) {
|
|
assert(N != 0);
|
|
unsigned P = Stack.size();
|
|
while (P > 0) {
|
|
bool Found = isDelimiter(Stack[P-1], N);
|
|
P--;
|
|
if (Found)
|
|
break;
|
|
}
|
|
// This will also remove the delimiter, if found.
|
|
Stack.resize(P);
|
|
}
|
|
|
|
// Move the stack iterator up by one.
|
|
unsigned DataFlowGraph::DefStack::nextUp(unsigned P) const {
|
|
// Get the next valid position after P (skipping all delimiters).
|
|
// The input position P does not have to point to a non-delimiter.
|
|
unsigned SS = Stack.size();
|
|
bool IsDelim;
|
|
assert(P < SS);
|
|
do {
|
|
P++;
|
|
IsDelim = isDelimiter(Stack[P-1]);
|
|
} while (P < SS && IsDelim);
|
|
assert(!IsDelim);
|
|
return P;
|
|
}
|
|
|
|
// Move the stack iterator down by one.
|
|
unsigned DataFlowGraph::DefStack::nextDown(unsigned P) const {
|
|
// Get the preceding valid position before P (skipping all delimiters).
|
|
// The input position P does not have to point to a non-delimiter.
|
|
assert(P > 0 && P <= Stack.size());
|
|
bool IsDelim = isDelimiter(Stack[P-1]);
|
|
do {
|
|
if (--P == 0)
|
|
break;
|
|
IsDelim = isDelimiter(Stack[P-1]);
|
|
} while (P > 0 && IsDelim);
|
|
assert(!IsDelim);
|
|
return P;
|
|
}
|
|
|
|
// Node management functions.
|
|
|
|
// Get the pointer to the node with the id N.
|
|
NodeBase *DataFlowGraph::ptr(NodeId N) const {
|
|
if (N == 0)
|
|
return nullptr;
|
|
return Memory.ptr(N);
|
|
}
|
|
|
|
// Get the id of the node at the address P.
|
|
NodeId DataFlowGraph::id(const NodeBase *P) const {
|
|
if (P == nullptr)
|
|
return 0;
|
|
return Memory.id(P);
|
|
}
|
|
|
|
// Allocate a new node and set the attributes to Attrs.
|
|
NodeAddr<NodeBase*> DataFlowGraph::newNode(uint16_t Attrs) {
|
|
NodeAddr<NodeBase*> P = Memory.New();
|
|
P.Addr->init();
|
|
P.Addr->setAttrs(Attrs);
|
|
return P;
|
|
}
|
|
|
|
// Make a copy of the given node B, except for the data-flow links, which
|
|
// are set to 0.
|
|
NodeAddr<NodeBase*> DataFlowGraph::cloneNode(const NodeAddr<NodeBase*> B) {
|
|
NodeAddr<NodeBase*> NA = newNode(0);
|
|
memcpy(NA.Addr, B.Addr, sizeof(NodeBase));
|
|
// Ref nodes need to have the data-flow links reset.
|
|
if (NA.Addr->getType() == NodeAttrs::Ref) {
|
|
NodeAddr<RefNode*> RA = NA;
|
|
RA.Addr->setReachingDef(0);
|
|
RA.Addr->setSibling(0);
|
|
if (NA.Addr->getKind() == NodeAttrs::Def) {
|
|
NodeAddr<DefNode*> DA = NA;
|
|
DA.Addr->setReachedDef(0);
|
|
DA.Addr->setReachedUse(0);
|
|
}
|
|
}
|
|
return NA;
|
|
}
|
|
|
|
|
|
// Allocation routines for specific node types/kinds.
|
|
|
|
NodeAddr<UseNode*> DataFlowGraph::newUse(NodeAddr<InstrNode*> Owner,
|
|
MachineOperand &Op, uint16_t Flags) {
|
|
NodeAddr<UseNode*> UA = newNode(NodeAttrs::Ref | NodeAttrs::Use | Flags);
|
|
UA.Addr->setRegRef(&Op);
|
|
return UA;
|
|
}
|
|
|
|
NodeAddr<PhiUseNode*> DataFlowGraph::newPhiUse(NodeAddr<PhiNode*> Owner,
|
|
RegisterRef RR, NodeAddr<BlockNode*> PredB, uint16_t Flags) {
|
|
NodeAddr<PhiUseNode*> PUA = newNode(NodeAttrs::Ref | NodeAttrs::Use | Flags);
|
|
assert(Flags & NodeAttrs::PhiRef);
|
|
PUA.Addr->setRegRef(RR);
|
|
PUA.Addr->setPredecessor(PredB.Id);
|
|
return PUA;
|
|
}
|
|
|
|
NodeAddr<DefNode*> DataFlowGraph::newDef(NodeAddr<InstrNode*> Owner,
|
|
MachineOperand &Op, uint16_t Flags) {
|
|
NodeAddr<DefNode*> DA = newNode(NodeAttrs::Ref | NodeAttrs::Def | Flags);
|
|
DA.Addr->setRegRef(&Op);
|
|
return DA;
|
|
}
|
|
|
|
NodeAddr<DefNode*> DataFlowGraph::newDef(NodeAddr<InstrNode*> Owner,
|
|
RegisterRef RR, uint16_t Flags) {
|
|
NodeAddr<DefNode*> DA = newNode(NodeAttrs::Ref | NodeAttrs::Def | Flags);
|
|
assert(Flags & NodeAttrs::PhiRef);
|
|
DA.Addr->setRegRef(RR);
|
|
return DA;
|
|
}
|
|
|
|
NodeAddr<PhiNode*> DataFlowGraph::newPhi(NodeAddr<BlockNode*> Owner) {
|
|
NodeAddr<PhiNode*> PA = newNode(NodeAttrs::Code | NodeAttrs::Phi);
|
|
Owner.Addr->addPhi(PA, *this);
|
|
return PA;
|
|
}
|
|
|
|
NodeAddr<StmtNode*> DataFlowGraph::newStmt(NodeAddr<BlockNode*> Owner,
|
|
MachineInstr *MI) {
|
|
NodeAddr<StmtNode*> SA = newNode(NodeAttrs::Code | NodeAttrs::Stmt);
|
|
SA.Addr->setCode(MI);
|
|
Owner.Addr->addMember(SA, *this);
|
|
return SA;
|
|
}
|
|
|
|
NodeAddr<BlockNode*> DataFlowGraph::newBlock(NodeAddr<FuncNode*> Owner,
|
|
MachineBasicBlock *BB) {
|
|
NodeAddr<BlockNode*> BA = newNode(NodeAttrs::Code | NodeAttrs::Block);
|
|
BA.Addr->setCode(BB);
|
|
Owner.Addr->addMember(BA, *this);
|
|
return BA;
|
|
}
|
|
|
|
NodeAddr<FuncNode*> DataFlowGraph::newFunc(MachineFunction *MF) {
|
|
NodeAddr<FuncNode*> FA = newNode(NodeAttrs::Code | NodeAttrs::Func);
|
|
FA.Addr->setCode(MF);
|
|
return FA;
|
|
}
|
|
|
|
// Build the data flow graph.
|
|
void DataFlowGraph::build(unsigned Options) {
|
|
reset();
|
|
Func = newFunc(&MF);
|
|
|
|
if (MF.empty())
|
|
return;
|
|
|
|
for (auto &B : MF) {
|
|
auto BA = newBlock(Func, &B);
|
|
for (auto &I : B) {
|
|
if (I.isDebugValue())
|
|
continue;
|
|
buildStmt(BA, I);
|
|
}
|
|
}
|
|
|
|
// Collect information about block references.
|
|
NodeAddr<BlockNode*> EA = Func.Addr->getEntryBlock(*this);
|
|
BlockRefsMap RefM;
|
|
buildBlockRefs(EA, RefM);
|
|
|
|
// Add function-entry phi nodes.
|
|
MachineRegisterInfo &MRI = MF.getRegInfo();
|
|
for (auto I = MRI.livein_begin(), E = MRI.livein_end(); I != E; ++I) {
|
|
NodeAddr<PhiNode*> PA = newPhi(EA);
|
|
RegisterRef RR = { I->first, 0 };
|
|
uint16_t PhiFlags = NodeAttrs::PhiRef | NodeAttrs::Preserving;
|
|
NodeAddr<DefNode*> DA = newDef(PA, RR, PhiFlags);
|
|
PA.Addr->addMember(DA, *this);
|
|
}
|
|
|
|
// Build a map "PhiM" which will contain, for each block, the set
|
|
// of references that will require phi definitions in that block.
|
|
BlockRefsMap PhiM;
|
|
auto Blocks = Func.Addr->members(*this);
|
|
for (NodeAddr<BlockNode*> BA : Blocks)
|
|
recordDefsForDF(PhiM, RefM, BA);
|
|
for (NodeAddr<BlockNode*> BA : Blocks)
|
|
buildPhis(PhiM, RefM, BA);
|
|
|
|
// Link all the refs. This will recursively traverse the dominator tree.
|
|
DefStackMap DM;
|
|
linkBlockRefs(DM, EA);
|
|
|
|
// Finally, remove all unused phi nodes.
|
|
if (!(Options & BuildOptions::KeepDeadPhis))
|
|
removeUnusedPhis();
|
|
}
|
|
|
|
// For each stack in the map DefM, push the delimiter for block B on it.
|
|
void DataFlowGraph::markBlock(NodeId B, DefStackMap &DefM) {
|
|
// Push block delimiters.
|
|
for (auto I = DefM.begin(), E = DefM.end(); I != E; ++I)
|
|
I->second.start_block(B);
|
|
}
|
|
|
|
// Remove all definitions coming from block B from each stack in DefM.
|
|
void DataFlowGraph::releaseBlock(NodeId B, DefStackMap &DefM) {
|
|
// Pop all defs from this block from the definition stack. Defs that were
|
|
// added to the map during the traversal of instructions will not have a
|
|
// delimiter, but for those, the whole stack will be emptied.
|
|
for (auto I = DefM.begin(), E = DefM.end(); I != E; ++I)
|
|
I->second.clear_block(B);
|
|
|
|
// Finally, remove empty stacks from the map.
|
|
for (auto I = DefM.begin(), E = DefM.end(), NextI = I; I != E; I = NextI) {
|
|
NextI = std::next(I);
|
|
// This preserves the validity of iterators other than I.
|
|
if (I->second.empty())
|
|
DefM.erase(I);
|
|
}
|
|
}
|
|
|
|
// Push all definitions from the instruction node IA to an appropriate
|
|
// stack in DefM.
|
|
void DataFlowGraph::pushDefs(NodeAddr<InstrNode*> IA, DefStackMap &DefM) {
|
|
NodeList Defs = IA.Addr->members_if(IsDef, *this);
|
|
NodeSet Visited;
|
|
#ifndef NDEBUG
|
|
RegisterSet Defined;
|
|
#endif
|
|
|
|
// The important objectives of this function are:
|
|
// - to be able to handle instructions both while the graph is being
|
|
// constructed, and after the graph has been constructed, and
|
|
// - maintain proper ordering of definitions on the stack for each
|
|
// register reference:
|
|
// - if there are two or more related defs in IA (i.e. coming from
|
|
// the same machine operand), then only push one def on the stack,
|
|
// - if there are multiple unrelated defs of non-overlapping
|
|
// subregisters of S, then the stack for S will have both (in an
|
|
// unspecified order), but the order does not matter from the data-
|
|
// -flow perspective.
|
|
|
|
for (NodeAddr<DefNode*> DA : Defs) {
|
|
if (Visited.count(DA.Id))
|
|
continue;
|
|
NodeList Rel = getRelatedRefs(IA, DA);
|
|
NodeAddr<DefNode*> PDA = Rel.front();
|
|
// Push the definition on the stack for the register and all aliases.
|
|
RegisterRef RR = PDA.Addr->getRegRef();
|
|
#ifndef NDEBUG
|
|
// Assert if the register is defined in two or more unrelated defs.
|
|
// This could happen if there are two or more def operands defining it.
|
|
if (!Defined.insert(RR).second) {
|
|
auto *MI = NodeAddr<StmtNode*>(IA).Addr->getCode();
|
|
dbgs() << "Multiple definitions of register: "
|
|
<< Print<RegisterRef>(RR, *this) << " in\n " << *MI
|
|
<< "in BB#" << MI->getParent()->getNumber() << '\n';
|
|
llvm_unreachable(nullptr);
|
|
}
|
|
#endif
|
|
DefM[RR].push(DA);
|
|
for (auto A : RAI.getAliasSet(RR)) {
|
|
assert(A != RR);
|
|
DefM[A].push(DA);
|
|
}
|
|
// Mark all the related defs as visited.
|
|
for (auto T : Rel)
|
|
Visited.insert(T.Id);
|
|
}
|
|
}
|
|
|
|
// Return the list of all reference nodes related to RA, including RA itself.
|
|
// See "getNextRelated" for the meaning of a "related reference".
|
|
NodeList DataFlowGraph::getRelatedRefs(NodeAddr<InstrNode*> IA,
|
|
NodeAddr<RefNode*> RA) const {
|
|
assert(IA.Id != 0 && RA.Id != 0);
|
|
|
|
NodeList Refs;
|
|
NodeId Start = RA.Id;
|
|
do {
|
|
Refs.push_back(RA);
|
|
RA = getNextRelated(IA, RA);
|
|
} while (RA.Id != 0 && RA.Id != Start);
|
|
return Refs;
|
|
}
|
|
|
|
|
|
// Clear all information in the graph.
|
|
void DataFlowGraph::reset() {
|
|
Memory.clear();
|
|
Func = NodeAddr<FuncNode*>();
|
|
}
|
|
|
|
|
|
// Return the next reference node in the instruction node IA that is related
|
|
// to RA. Conceptually, two reference nodes are related if they refer to the
|
|
// same instance of a register access, but differ in flags or other minor
|
|
// characteristics. Specific examples of related nodes are shadow reference
|
|
// nodes.
|
|
// Return the equivalent of nullptr if there are no more related references.
|
|
NodeAddr<RefNode*> DataFlowGraph::getNextRelated(NodeAddr<InstrNode*> IA,
|
|
NodeAddr<RefNode*> RA) const {
|
|
assert(IA.Id != 0 && RA.Id != 0);
|
|
|
|
auto Related = [RA](NodeAddr<RefNode*> TA) -> bool {
|
|
if (TA.Addr->getKind() != RA.Addr->getKind())
|
|
return false;
|
|
if (TA.Addr->getRegRef() != RA.Addr->getRegRef())
|
|
return false;
|
|
return true;
|
|
};
|
|
auto RelatedStmt = [&Related,RA](NodeAddr<RefNode*> TA) -> bool {
|
|
return Related(TA) &&
|
|
&RA.Addr->getOp() == &TA.Addr->getOp();
|
|
};
|
|
auto RelatedPhi = [&Related,RA](NodeAddr<RefNode*> TA) -> bool {
|
|
if (!Related(TA))
|
|
return false;
|
|
if (TA.Addr->getKind() != NodeAttrs::Use)
|
|
return true;
|
|
// For phi uses, compare predecessor blocks.
|
|
const NodeAddr<const PhiUseNode*> TUA = TA;
|
|
const NodeAddr<const PhiUseNode*> RUA = RA;
|
|
return TUA.Addr->getPredecessor() == RUA.Addr->getPredecessor();
|
|
};
|
|
|
|
RegisterRef RR = RA.Addr->getRegRef();
|
|
if (IA.Addr->getKind() == NodeAttrs::Stmt)
|
|
return RA.Addr->getNextRef(RR, RelatedStmt, true, *this);
|
|
return RA.Addr->getNextRef(RR, RelatedPhi, true, *this);
|
|
}
|
|
|
|
// Find the next node related to RA in IA that satisfies condition P.
|
|
// If such a node was found, return a pair where the second element is the
|
|
// located node. If such a node does not exist, return a pair where the
|
|
// first element is the element after which such a node should be inserted,
|
|
// and the second element is a null-address.
|
|
template <typename Predicate>
|
|
std::pair<NodeAddr<RefNode*>,NodeAddr<RefNode*>>
|
|
DataFlowGraph::locateNextRef(NodeAddr<InstrNode*> IA, NodeAddr<RefNode*> RA,
|
|
Predicate P) const {
|
|
assert(IA.Id != 0 && RA.Id != 0);
|
|
|
|
NodeAddr<RefNode*> NA;
|
|
NodeId Start = RA.Id;
|
|
while (true) {
|
|
NA = getNextRelated(IA, RA);
|
|
if (NA.Id == 0 || NA.Id == Start)
|
|
break;
|
|
if (P(NA))
|
|
break;
|
|
RA = NA;
|
|
}
|
|
|
|
if (NA.Id != 0 && NA.Id != Start)
|
|
return std::make_pair(RA, NA);
|
|
return std::make_pair(RA, NodeAddr<RefNode*>());
|
|
}
|
|
|
|
// Get the next shadow node in IA corresponding to RA, and optionally create
|
|
// such a node if it does not exist.
|
|
NodeAddr<RefNode*> DataFlowGraph::getNextShadow(NodeAddr<InstrNode*> IA,
|
|
NodeAddr<RefNode*> RA, bool Create) {
|
|
assert(IA.Id != 0 && RA.Id != 0);
|
|
|
|
uint16_t Flags = RA.Addr->getFlags() | NodeAttrs::Shadow;
|
|
auto IsShadow = [Flags] (NodeAddr<RefNode*> TA) -> bool {
|
|
return TA.Addr->getFlags() == Flags;
|
|
};
|
|
auto Loc = locateNextRef(IA, RA, IsShadow);
|
|
if (Loc.second.Id != 0 || !Create)
|
|
return Loc.second;
|
|
|
|
// Create a copy of RA and mark is as shadow.
|
|
NodeAddr<RefNode*> NA = cloneNode(RA);
|
|
NA.Addr->setFlags(Flags | NodeAttrs::Shadow);
|
|
IA.Addr->addMemberAfter(Loc.first, NA, *this);
|
|
return NA;
|
|
}
|
|
|
|
// Get the next shadow node in IA corresponding to RA. Return null-address
|
|
// if such a node does not exist.
|
|
NodeAddr<RefNode*> DataFlowGraph::getNextShadow(NodeAddr<InstrNode*> IA,
|
|
NodeAddr<RefNode*> RA) const {
|
|
assert(IA.Id != 0 && RA.Id != 0);
|
|
uint16_t Flags = RA.Addr->getFlags() | NodeAttrs::Shadow;
|
|
auto IsShadow = [Flags] (NodeAddr<RefNode*> TA) -> bool {
|
|
return TA.Addr->getFlags() == Flags;
|
|
};
|
|
return locateNextRef(IA, RA, IsShadow).second;
|
|
}
|
|
|
|
// Create a new statement node in the block node BA that corresponds to
|
|
// the machine instruction MI.
|
|
void DataFlowGraph::buildStmt(NodeAddr<BlockNode*> BA, MachineInstr &In) {
|
|
auto SA = newStmt(BA, &In);
|
|
|
|
auto isCall = [] (const MachineInstr &In) -> bool {
|
|
if (In.isCall())
|
|
return true;
|
|
// Is tail call?
|
|
if (In.isBranch())
|
|
for (auto &Op : In.operands())
|
|
if (Op.isGlobal() || Op.isSymbol())
|
|
return true;
|
|
return false;
|
|
};
|
|
|
|
// Collect a set of registers that this instruction implicitly uses
|
|
// or defines. Implicit operands from an instruction will be ignored
|
|
// unless they are listed here.
|
|
RegisterSet ImpUses, ImpDefs;
|
|
if (const uint16_t *ImpD = In.getDesc().getImplicitDefs())
|
|
while (uint16_t R = *ImpD++)
|
|
ImpDefs.insert({R, 0});
|
|
if (const uint16_t *ImpU = In.getDesc().getImplicitUses())
|
|
while (uint16_t R = *ImpU++)
|
|
ImpUses.insert({R, 0});
|
|
|
|
bool NeedsImplicit = isCall(In) || In.isInlineAsm() || In.isReturn();
|
|
bool IsPredicated = TII.isPredicated(In);
|
|
unsigned NumOps = In.getNumOperands();
|
|
|
|
// Avoid duplicate implicit defs. This will not detect cases of implicit
|
|
// defs that define registers that overlap, but it is not clear how to
|
|
// interpret that in the absence of explicit defs. Overlapping explicit
|
|
// defs are likely illegal already.
|
|
RegisterSet DoneDefs;
|
|
// Process explicit defs first.
|
|
for (unsigned OpN = 0; OpN < NumOps; ++OpN) {
|
|
MachineOperand &Op = In.getOperand(OpN);
|
|
if (!Op.isReg() || !Op.isDef() || Op.isImplicit())
|
|
continue;
|
|
RegisterRef RR = { Op.getReg(), Op.getSubReg() };
|
|
uint16_t Flags = NodeAttrs::None;
|
|
if (TOI.isPreserving(In, OpN))
|
|
Flags |= NodeAttrs::Preserving;
|
|
if (TOI.isClobbering(In, OpN))
|
|
Flags |= NodeAttrs::Clobbering;
|
|
if (TOI.isFixedReg(In, OpN))
|
|
Flags |= NodeAttrs::Fixed;
|
|
NodeAddr<DefNode*> DA = newDef(SA, Op, Flags);
|
|
SA.Addr->addMember(DA, *this);
|
|
DoneDefs.insert(RR);
|
|
}
|
|
|
|
// Process implicit defs, skipping those that have already been added
|
|
// as explicit.
|
|
for (unsigned OpN = 0; OpN < NumOps; ++OpN) {
|
|
MachineOperand &Op = In.getOperand(OpN);
|
|
if (!Op.isReg() || !Op.isDef() || !Op.isImplicit())
|
|
continue;
|
|
RegisterRef RR = { Op.getReg(), Op.getSubReg() };
|
|
if (!NeedsImplicit && !ImpDefs.count(RR))
|
|
continue;
|
|
if (DoneDefs.count(RR))
|
|
continue;
|
|
uint16_t Flags = NodeAttrs::None;
|
|
if (TOI.isPreserving(In, OpN))
|
|
Flags |= NodeAttrs::Preserving;
|
|
if (TOI.isClobbering(In, OpN))
|
|
Flags |= NodeAttrs::Clobbering;
|
|
if (TOI.isFixedReg(In, OpN))
|
|
Flags |= NodeAttrs::Fixed;
|
|
NodeAddr<DefNode*> DA = newDef(SA, Op, Flags);
|
|
SA.Addr->addMember(DA, *this);
|
|
DoneDefs.insert(RR);
|
|
}
|
|
|
|
for (unsigned OpN = 0; OpN < NumOps; ++OpN) {
|
|
MachineOperand &Op = In.getOperand(OpN);
|
|
if (!Op.isReg() || !Op.isUse())
|
|
continue;
|
|
RegisterRef RR = { Op.getReg(), Op.getSubReg() };
|
|
// Add implicit uses on return and call instructions, and on predicated
|
|
// instructions regardless of whether or not they appear in the instruction
|
|
// descriptor's list.
|
|
bool Implicit = Op.isImplicit();
|
|
bool TakeImplicit = NeedsImplicit || IsPredicated;
|
|
if (Implicit && !TakeImplicit && !ImpUses.count(RR))
|
|
continue;
|
|
uint16_t Flags = NodeAttrs::None;
|
|
if (TOI.isFixedReg(In, OpN))
|
|
Flags |= NodeAttrs::Fixed;
|
|
NodeAddr<UseNode*> UA = newUse(SA, Op, Flags);
|
|
SA.Addr->addMember(UA, *this);
|
|
}
|
|
}
|
|
|
|
// Build a map that for each block will have the set of all references from
|
|
// that block, and from all blocks dominated by it.
|
|
void DataFlowGraph::buildBlockRefs(NodeAddr<BlockNode*> BA,
|
|
BlockRefsMap &RefM) {
|
|
auto &Refs = RefM[BA.Id];
|
|
MachineDomTreeNode *N = MDT.getNode(BA.Addr->getCode());
|
|
assert(N);
|
|
for (auto I : *N) {
|
|
MachineBasicBlock *SB = I->getBlock();
|
|
auto SBA = Func.Addr->findBlock(SB, *this);
|
|
buildBlockRefs(SBA, RefM);
|
|
const auto &SRs = RefM[SBA.Id];
|
|
Refs.insert(SRs.begin(), SRs.end());
|
|
}
|
|
|
|
for (NodeAddr<InstrNode*> IA : BA.Addr->members(*this))
|
|
for (NodeAddr<RefNode*> RA : IA.Addr->members(*this))
|
|
Refs.insert(RA.Addr->getRegRef());
|
|
}
|
|
|
|
// Scan all defs in the block node BA and record in PhiM the locations of
|
|
// phi nodes corresponding to these defs.
|
|
void DataFlowGraph::recordDefsForDF(BlockRefsMap &PhiM, BlockRefsMap &RefM,
|
|
NodeAddr<BlockNode*> BA) {
|
|
// Check all defs from block BA and record them in each block in BA's
|
|
// iterated dominance frontier. This information will later be used to
|
|
// create phi nodes.
|
|
MachineBasicBlock *BB = BA.Addr->getCode();
|
|
assert(BB);
|
|
auto DFLoc = MDF.find(BB);
|
|
if (DFLoc == MDF.end() || DFLoc->second.empty())
|
|
return;
|
|
|
|
// Traverse all instructions in the block and collect the set of all
|
|
// defined references. For each reference there will be a phi created
|
|
// in the block's iterated dominance frontier.
|
|
// This is done to make sure that each defined reference gets only one
|
|
// phi node, even if it is defined multiple times.
|
|
RegisterSet Defs;
|
|
for (auto I : BA.Addr->members(*this)) {
|
|
assert(I.Addr->getType() == NodeAttrs::Code);
|
|
assert(I.Addr->getKind() == NodeAttrs::Phi ||
|
|
I.Addr->getKind() == NodeAttrs::Stmt);
|
|
NodeAddr<InstrNode*> IA = I;
|
|
for (NodeAddr<RefNode*> RA : IA.Addr->members_if(IsDef, *this))
|
|
Defs.insert(RA.Addr->getRegRef());
|
|
}
|
|
|
|
// Finally, add the set of defs to each block in the iterated dominance
|
|
// frontier.
|
|
const MachineDominanceFrontier::DomSetType &DF = DFLoc->second;
|
|
SetVector<MachineBasicBlock*> IDF(DF.begin(), DF.end());
|
|
for (unsigned i = 0; i < IDF.size(); ++i) {
|
|
auto F = MDF.find(IDF[i]);
|
|
if (F != MDF.end())
|
|
IDF.insert(F->second.begin(), F->second.end());
|
|
}
|
|
|
|
// Get the register references that are reachable from this block.
|
|
RegisterSet &Refs = RefM[BA.Id];
|
|
for (auto DB : IDF) {
|
|
auto DBA = Func.Addr->findBlock(DB, *this);
|
|
const auto &Rs = RefM[DBA.Id];
|
|
Refs.insert(Rs.begin(), Rs.end());
|
|
}
|
|
|
|
for (auto DB : IDF) {
|
|
auto DBA = Func.Addr->findBlock(DB, *this);
|
|
PhiM[DBA.Id].insert(Defs.begin(), Defs.end());
|
|
}
|
|
}
|
|
|
|
// Given the locations of phi nodes in the map PhiM, create the phi nodes
|
|
// that are located in the block node BA.
|
|
void DataFlowGraph::buildPhis(BlockRefsMap &PhiM, BlockRefsMap &RefM,
|
|
NodeAddr<BlockNode*> BA) {
|
|
// Check if this blocks has any DF defs, i.e. if there are any defs
|
|
// that this block is in the iterated dominance frontier of.
|
|
auto HasDF = PhiM.find(BA.Id);
|
|
if (HasDF == PhiM.end() || HasDF->second.empty())
|
|
return;
|
|
|
|
// First, remove all R in Refs in such that there exists T in Refs
|
|
// such that T covers R. In other words, only leave those refs that
|
|
// are not covered by another ref (i.e. maximal with respect to covering).
|
|
|
|
auto MaxCoverIn = [this] (RegisterRef RR, RegisterSet &RRs) -> RegisterRef {
|
|
for (auto I : RRs)
|
|
if (I != RR && RAI.covers(I, RR))
|
|
RR = I;
|
|
return RR;
|
|
};
|
|
|
|
RegisterSet MaxDF;
|
|
for (auto I : HasDF->second)
|
|
MaxDF.insert(MaxCoverIn(I, HasDF->second));
|
|
|
|
std::vector<RegisterRef> MaxRefs;
|
|
auto &RefB = RefM[BA.Id];
|
|
for (auto I : MaxDF)
|
|
MaxRefs.push_back(MaxCoverIn(I, RefB));
|
|
|
|
// Now, for each R in MaxRefs, get the alias closure of R. If the closure
|
|
// only has R in it, create a phi a def for R. Otherwise, create a phi,
|
|
// and add a def for each S in the closure.
|
|
|
|
// Sort the refs so that the phis will be created in a deterministic order.
|
|
std::sort(MaxRefs.begin(), MaxRefs.end());
|
|
// Remove duplicates.
|
|
auto NewEnd = std::unique(MaxRefs.begin(), MaxRefs.end());
|
|
MaxRefs.erase(NewEnd, MaxRefs.end());
|
|
|
|
auto Aliased = [this,&MaxRefs](RegisterRef RR,
|
|
std::vector<unsigned> &Closure) -> bool {
|
|
for (auto I : Closure)
|
|
if (RAI.alias(RR, MaxRefs[I]))
|
|
return true;
|
|
return false;
|
|
};
|
|
|
|
// Prepare a list of NodeIds of the block's predecessors.
|
|
std::vector<NodeId> PredList;
|
|
const MachineBasicBlock *MBB = BA.Addr->getCode();
|
|
for (auto PB : MBB->predecessors()) {
|
|
auto B = Func.Addr->findBlock(PB, *this);
|
|
PredList.push_back(B.Id);
|
|
}
|
|
|
|
while (!MaxRefs.empty()) {
|
|
// Put the first element in the closure, and then add all subsequent
|
|
// elements from MaxRefs to it, if they alias at least one element
|
|
// already in the closure.
|
|
// ClosureIdx: vector of indices in MaxRefs of members of the closure.
|
|
std::vector<unsigned> ClosureIdx = { 0 };
|
|
for (unsigned i = 1; i != MaxRefs.size(); ++i)
|
|
if (Aliased(MaxRefs[i], ClosureIdx))
|
|
ClosureIdx.push_back(i);
|
|
|
|
// Build a phi for the closure.
|
|
unsigned CS = ClosureIdx.size();
|
|
NodeAddr<PhiNode*> PA = newPhi(BA);
|
|
|
|
// Add defs.
|
|
for (unsigned X = 0; X != CS; ++X) {
|
|
RegisterRef RR = MaxRefs[ClosureIdx[X]];
|
|
uint16_t PhiFlags = NodeAttrs::PhiRef | NodeAttrs::Preserving;
|
|
NodeAddr<DefNode*> DA = newDef(PA, RR, PhiFlags);
|
|
PA.Addr->addMember(DA, *this);
|
|
}
|
|
// Add phi uses.
|
|
for (auto P : PredList) {
|
|
auto PBA = addr<BlockNode*>(P);
|
|
for (unsigned X = 0; X != CS; ++X) {
|
|
RegisterRef RR = MaxRefs[ClosureIdx[X]];
|
|
NodeAddr<PhiUseNode*> PUA = newPhiUse(PA, RR, PBA);
|
|
PA.Addr->addMember(PUA, *this);
|
|
}
|
|
}
|
|
|
|
// Erase from MaxRefs all elements in the closure.
|
|
auto Begin = MaxRefs.begin();
|
|
for (unsigned i = ClosureIdx.size(); i != 0; --i)
|
|
MaxRefs.erase(Begin + ClosureIdx[i-1]);
|
|
}
|
|
}
|
|
|
|
// Remove any unneeded phi nodes that were created during the build process.
|
|
void DataFlowGraph::removeUnusedPhis() {
|
|
// This will remove unused phis, i.e. phis where each def does not reach
|
|
// any uses or other defs. This will not detect or remove circular phi
|
|
// chains that are otherwise dead. Unused/dead phis are created during
|
|
// the build process and this function is intended to remove these cases
|
|
// that are easily determinable to be unnecessary.
|
|
|
|
SetVector<NodeId> PhiQ;
|
|
for (NodeAddr<BlockNode*> BA : Func.Addr->members(*this)) {
|
|
for (auto P : BA.Addr->members_if(IsPhi, *this))
|
|
PhiQ.insert(P.Id);
|
|
}
|
|
|
|
static auto HasUsedDef = [](NodeList &Ms) -> bool {
|
|
for (auto M : Ms) {
|
|
if (M.Addr->getKind() != NodeAttrs::Def)
|
|
continue;
|
|
NodeAddr<DefNode*> DA = M;
|
|
if (DA.Addr->getReachedDef() != 0 || DA.Addr->getReachedUse() != 0)
|
|
return true;
|
|
}
|
|
return false;
|
|
};
|
|
|
|
// Any phi, if it is removed, may affect other phis (make them dead).
|
|
// For each removed phi, collect the potentially affected phis and add
|
|
// them back to the queue.
|
|
while (!PhiQ.empty()) {
|
|
auto PA = addr<PhiNode*>(PhiQ[0]);
|
|
PhiQ.remove(PA.Id);
|
|
NodeList Refs = PA.Addr->members(*this);
|
|
if (HasUsedDef(Refs))
|
|
continue;
|
|
for (NodeAddr<RefNode*> RA : Refs) {
|
|
if (NodeId RD = RA.Addr->getReachingDef()) {
|
|
auto RDA = addr<DefNode*>(RD);
|
|
NodeAddr<InstrNode*> OA = RDA.Addr->getOwner(*this);
|
|
if (IsPhi(OA))
|
|
PhiQ.insert(OA.Id);
|
|
}
|
|
if (RA.Addr->isDef())
|
|
unlinkDef(RA, true);
|
|
else
|
|
unlinkUse(RA, true);
|
|
}
|
|
NodeAddr<BlockNode*> BA = PA.Addr->getOwner(*this);
|
|
BA.Addr->removeMember(PA, *this);
|
|
}
|
|
}
|
|
|
|
// For a given reference node TA in an instruction node IA, connect the
|
|
// reaching def of TA to the appropriate def node. Create any shadow nodes
|
|
// as appropriate.
|
|
template <typename T>
|
|
void DataFlowGraph::linkRefUp(NodeAddr<InstrNode*> IA, NodeAddr<T> TA,
|
|
DefStack &DS) {
|
|
if (DS.empty())
|
|
return;
|
|
RegisterRef RR = TA.Addr->getRegRef();
|
|
NodeAddr<T> TAP;
|
|
|
|
// References from the def stack that have been examined so far.
|
|
RegisterSet Defs;
|
|
|
|
for (auto I = DS.top(), E = DS.bottom(); I != E; I.down()) {
|
|
RegisterRef QR = I->Addr->getRegRef();
|
|
auto AliasQR = [QR,this] (RegisterRef RR) -> bool {
|
|
return RAI.alias(QR, RR);
|
|
};
|
|
bool PrecUp = RAI.covers(QR, RR);
|
|
// Skip all defs that are aliased to any of the defs that we have already
|
|
// seen. If we encounter a covering def, stop the stack traversal early.
|
|
if (std::any_of(Defs.begin(), Defs.end(), AliasQR)) {
|
|
if (PrecUp)
|
|
break;
|
|
continue;
|
|
}
|
|
// The reaching def.
|
|
NodeAddr<DefNode*> RDA = *I;
|
|
|
|
// Pick the reached node.
|
|
if (TAP.Id == 0) {
|
|
TAP = TA;
|
|
} else {
|
|
// Mark the existing ref as "shadow" and create a new shadow.
|
|
TAP.Addr->setFlags(TAP.Addr->getFlags() | NodeAttrs::Shadow);
|
|
TAP = getNextShadow(IA, TAP, true);
|
|
}
|
|
|
|
// Create the link.
|
|
TAP.Addr->linkToDef(TAP.Id, RDA);
|
|
|
|
if (PrecUp)
|
|
break;
|
|
Defs.insert(QR);
|
|
}
|
|
}
|
|
|
|
// Create data-flow links for all reference nodes in the statement node SA.
|
|
void DataFlowGraph::linkStmtRefs(DefStackMap &DefM, NodeAddr<StmtNode*> SA) {
|
|
RegisterSet Defs;
|
|
|
|
// Link all nodes (upwards in the data-flow) with their reaching defs.
|
|
for (NodeAddr<RefNode*> RA : SA.Addr->members(*this)) {
|
|
uint16_t Kind = RA.Addr->getKind();
|
|
assert(Kind == NodeAttrs::Def || Kind == NodeAttrs::Use);
|
|
RegisterRef RR = RA.Addr->getRegRef();
|
|
// Do not process multiple defs of the same reference.
|
|
if (Kind == NodeAttrs::Def && Defs.count(RR))
|
|
continue;
|
|
Defs.insert(RR);
|
|
|
|
auto F = DefM.find(RR);
|
|
if (F == DefM.end())
|
|
continue;
|
|
DefStack &DS = F->second;
|
|
if (Kind == NodeAttrs::Use)
|
|
linkRefUp<UseNode*>(SA, RA, DS);
|
|
else if (Kind == NodeAttrs::Def)
|
|
linkRefUp<DefNode*>(SA, RA, DS);
|
|
else
|
|
llvm_unreachable("Unexpected node in instruction");
|
|
}
|
|
}
|
|
|
|
// Create data-flow links for all instructions in the block node BA. This
|
|
// will include updating any phi nodes in BA.
|
|
void DataFlowGraph::linkBlockRefs(DefStackMap &DefM, NodeAddr<BlockNode*> BA) {
|
|
// Push block delimiters.
|
|
markBlock(BA.Id, DefM);
|
|
|
|
assert(BA.Addr && "block node address is needed to create a data-flow link");
|
|
// For each non-phi instruction in the block, link all the defs and uses
|
|
// to their reaching defs. For any member of the block (including phis),
|
|
// push the defs on the corresponding stacks.
|
|
for (NodeAddr<InstrNode*> IA : BA.Addr->members(*this)) {
|
|
// Ignore phi nodes here. They will be linked part by part from the
|
|
// predecessors.
|
|
if (IA.Addr->getKind() == NodeAttrs::Stmt)
|
|
linkStmtRefs(DefM, IA);
|
|
|
|
// Push the definitions on the stack.
|
|
pushDefs(IA, DefM);
|
|
}
|
|
|
|
// Recursively process all children in the dominator tree.
|
|
MachineDomTreeNode *N = MDT.getNode(BA.Addr->getCode());
|
|
for (auto I : *N) {
|
|
MachineBasicBlock *SB = I->getBlock();
|
|
auto SBA = Func.Addr->findBlock(SB, *this);
|
|
linkBlockRefs(DefM, SBA);
|
|
}
|
|
|
|
// Link the phi uses from the successor blocks.
|
|
auto IsUseForBA = [BA](NodeAddr<NodeBase*> NA) -> bool {
|
|
if (NA.Addr->getKind() != NodeAttrs::Use)
|
|
return false;
|
|
assert(NA.Addr->getFlags() & NodeAttrs::PhiRef);
|
|
NodeAddr<PhiUseNode*> PUA = NA;
|
|
return PUA.Addr->getPredecessor() == BA.Id;
|
|
};
|
|
MachineBasicBlock *MBB = BA.Addr->getCode();
|
|
for (auto SB : MBB->successors()) {
|
|
auto SBA = Func.Addr->findBlock(SB, *this);
|
|
for (NodeAddr<InstrNode*> IA : SBA.Addr->members_if(IsPhi, *this)) {
|
|
// Go over each phi use associated with MBB, and link it.
|
|
for (auto U : IA.Addr->members_if(IsUseForBA, *this)) {
|
|
NodeAddr<PhiUseNode*> PUA = U;
|
|
RegisterRef RR = PUA.Addr->getRegRef();
|
|
linkRefUp<UseNode*>(IA, PUA, DefM[RR]);
|
|
}
|
|
}
|
|
}
|
|
|
|
// Pop all defs from this block from the definition stacks.
|
|
releaseBlock(BA.Id, DefM);
|
|
}
|
|
|
|
// Remove the use node UA from any data-flow and structural links.
|
|
void DataFlowGraph::unlinkUseDF(NodeAddr<UseNode*> UA) {
|
|
NodeId RD = UA.Addr->getReachingDef();
|
|
NodeId Sib = UA.Addr->getSibling();
|
|
|
|
if (RD == 0) {
|
|
assert(Sib == 0);
|
|
return;
|
|
}
|
|
|
|
auto RDA = addr<DefNode*>(RD);
|
|
auto TA = addr<UseNode*>(RDA.Addr->getReachedUse());
|
|
if (TA.Id == UA.Id) {
|
|
RDA.Addr->setReachedUse(Sib);
|
|
return;
|
|
}
|
|
|
|
while (TA.Id != 0) {
|
|
NodeId S = TA.Addr->getSibling();
|
|
if (S == UA.Id) {
|
|
TA.Addr->setSibling(UA.Addr->getSibling());
|
|
return;
|
|
}
|
|
TA = addr<UseNode*>(S);
|
|
}
|
|
}
|
|
|
|
// Remove the def node DA from any data-flow and structural links.
|
|
void DataFlowGraph::unlinkDefDF(NodeAddr<DefNode*> DA) {
|
|
//
|
|
// RD
|
|
// | reached
|
|
// | def
|
|
// :
|
|
// .
|
|
// +----+
|
|
// ... -- | DA | -- ... -- 0 : sibling chain of DA
|
|
// +----+
|
|
// | | reached
|
|
// | : def
|
|
// | .
|
|
// | ... : Siblings (defs)
|
|
// |
|
|
// : reached
|
|
// . use
|
|
// ... : sibling chain of reached uses
|
|
|
|
NodeId RD = DA.Addr->getReachingDef();
|
|
|
|
// Visit all siblings of the reached def and reset their reaching defs.
|
|
// Also, defs reached by DA are now "promoted" to being reached by RD,
|
|
// so all of them will need to be spliced into the sibling chain where
|
|
// DA belongs.
|
|
auto getAllNodes = [this] (NodeId N) -> NodeList {
|
|
NodeList Res;
|
|
while (N) {
|
|
auto RA = addr<RefNode*>(N);
|
|
// Keep the nodes in the exact sibling order.
|
|
Res.push_back(RA);
|
|
N = RA.Addr->getSibling();
|
|
}
|
|
return Res;
|
|
};
|
|
NodeList ReachedDefs = getAllNodes(DA.Addr->getReachedDef());
|
|
NodeList ReachedUses = getAllNodes(DA.Addr->getReachedUse());
|
|
|
|
if (RD == 0) {
|
|
for (NodeAddr<RefNode*> I : ReachedDefs)
|
|
I.Addr->setSibling(0);
|
|
for (NodeAddr<RefNode*> I : ReachedUses)
|
|
I.Addr->setSibling(0);
|
|
}
|
|
for (NodeAddr<DefNode*> I : ReachedDefs)
|
|
I.Addr->setReachingDef(RD);
|
|
for (NodeAddr<UseNode*> I : ReachedUses)
|
|
I.Addr->setReachingDef(RD);
|
|
|
|
NodeId Sib = DA.Addr->getSibling();
|
|
if (RD == 0) {
|
|
assert(Sib == 0);
|
|
return;
|
|
}
|
|
|
|
// Update the reaching def node and remove DA from the sibling list.
|
|
auto RDA = addr<DefNode*>(RD);
|
|
auto TA = addr<DefNode*>(RDA.Addr->getReachedDef());
|
|
if (TA.Id == DA.Id) {
|
|
// If DA is the first reached def, just update the RD's reached def
|
|
// to the DA's sibling.
|
|
RDA.Addr->setReachedDef(Sib);
|
|
} else {
|
|
// Otherwise, traverse the sibling list of the reached defs and remove
|
|
// DA from it.
|
|
while (TA.Id != 0) {
|
|
NodeId S = TA.Addr->getSibling();
|
|
if (S == DA.Id) {
|
|
TA.Addr->setSibling(Sib);
|
|
break;
|
|
}
|
|
TA = addr<DefNode*>(S);
|
|
}
|
|
}
|
|
|
|
// Splice the DA's reached defs into the RDA's reached def chain.
|
|
if (!ReachedDefs.empty()) {
|
|
auto Last = NodeAddr<DefNode*>(ReachedDefs.back());
|
|
Last.Addr->setSibling(RDA.Addr->getReachedDef());
|
|
RDA.Addr->setReachedDef(ReachedDefs.front().Id);
|
|
}
|
|
// Splice the DA's reached uses into the RDA's reached use chain.
|
|
if (!ReachedUses.empty()) {
|
|
auto Last = NodeAddr<UseNode*>(ReachedUses.back());
|
|
Last.Addr->setSibling(RDA.Addr->getReachedUse());
|
|
RDA.Addr->setReachedUse(ReachedUses.front().Id);
|
|
}
|
|
}
|