72 lines
2.9 KiB
C
72 lines
2.9 KiB
C
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//===- LiveIntervalCalc.h - Calculate live intervals -----------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// The LiveIntervalCalc class is an extension of LiveRangeCalc targeted to the
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// computation and modification of the LiveInterval variants of LiveRanges.
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// LiveIntervals are meant to track liveness of registers and stack slots and
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// LiveIntervalCalc adds to LiveRangeCalc all the machinery requied to
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// construct the liveness of virtual registers tracked by a LiveInterval.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_LIB_CODEGEN_LIVEINTERVALCALC_H
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#define LLVM_LIB_CODEGEN_LIVEINTERVALCALC_H
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#include "llvm/CodeGen/LiveRangeCalc.h"
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namespace llvm {
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template <class NodeT> class DomTreeNodeBase;
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using MachineDomTreeNode = DomTreeNodeBase<MachineBasicBlock>;
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class LiveIntervalCalc : public LiveRangeCalc {
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/// Extend the live range of @p LR to reach all uses of Reg.
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///
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/// If @p LR is a main range, or if @p LI is null, then all uses must be
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/// jointly dominated by the definitions from @p LR. If @p LR is a subrange
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/// of the live interval @p LI, corresponding to lane mask @p LaneMask,
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/// all uses must be jointly dominated by the definitions from @p LR
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/// together with definitions of other lanes where @p LR becomes undefined
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/// (via <def,read-undef> operands).
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/// If @p LR is a main range, the @p LaneMask should be set to ~0, i.e.
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/// LaneBitmask::getAll().
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void extendToUses(LiveRange &LR, Register Reg, LaneBitmask LaneMask,
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LiveInterval *LI = nullptr);
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public:
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LiveIntervalCalc() = default;
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/// createDeadDefs - Create a dead def in LI for every def operand of Reg.
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/// Each instruction defining Reg gets a new VNInfo with a corresponding
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/// minimal live range.
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void createDeadDefs(LiveRange &LR, Register Reg);
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/// Extend the live range of @p LR to reach all uses of Reg.
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///
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/// All uses must be jointly dominated by existing liveness. PHI-defs are
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/// inserted as needed to preserve SSA form.
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void extendToUses(LiveRange &LR, MCRegister PhysReg) {
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extendToUses(LR, PhysReg, LaneBitmask::getAll());
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}
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/// Calculates liveness for the register specified in live interval @p LI.
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/// Creates subregister live ranges as needed if subreg liveness tracking is
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/// enabled.
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void calculate(LiveInterval &LI, bool TrackSubRegs);
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/// For live interval \p LI with correct SubRanges construct matching
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/// information for the main live range. Expects the main live range to not
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/// have any segments or value numbers.
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void constructMainRangeFromSubranges(LiveInterval &LI);
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};
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} // end namespace llvm
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#endif // LLVM_LIB_CODEGEN_LIVEINTERVALCALC_H
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