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+//===-- llvm/CodeGen/TargetSchedule.h - Sched Machine Model -----*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines a wrapper around MCSchedModel that allows the interface to
+// benefit from information currently only available in TargetInstrInfo.
+// Ideally, the scheduling interface would be fully defined in the MC layer.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TARGET_TARGETSCHEDMODEL_H
+#define LLVM_TARGET_TARGETSCHEDMODEL_H
+
+#include "llvm/Target/TargetSubtargetInfo.h"
+#include "llvm/MC/MCSchedule.h"
+#include "llvm/MC/MCInstrItineraries.h"
+#include "llvm/ADT/SmallVector.h"
+
+namespace llvm {
+
+class TargetRegisterInfo;
+class TargetSubtargetInfo;
+class TargetInstrInfo;
+class MachineInstr;
+
+/// Provide an instruction scheduling machine model to CodeGen passes.
+class TargetSchedModel {
+ // For efficiency, hold a copy of the statically defined MCSchedModel for this
+ // processor.
+ MCSchedModel SchedModel;
+ InstrItineraryData InstrItins;
+ const TargetSubtargetInfo *STI;
+ const TargetInstrInfo *TII;
+
+ SmallVector<unsigned, 16> ResourceFactors;
+ unsigned MicroOpFactor; // Multiply to normalize microops to resource units.
+ unsigned ResourceLCM; // Resource units per cycle. Latency normalization factor.
+public:
+ TargetSchedModel(): STI(0), TII(0) {}
+
+ /// \brief Initialize the machine model for instruction scheduling.
+ ///
+ /// The machine model API keeps a copy of the top-level MCSchedModel table
+ /// indices and may query TargetSubtargetInfo and TargetInstrInfo to resolve
+ /// dynamic properties.
+ void init(const MCSchedModel &sm, const TargetSubtargetInfo *sti,
+ const TargetInstrInfo *tii);
+
+ /// Return the MCSchedClassDesc for this instruction.
+ const MCSchedClassDesc *resolveSchedClass(const MachineInstr *MI) const;
+
+ /// \brief TargetInstrInfo getter.
+ const TargetInstrInfo *getInstrInfo() const { return TII; }
+
+ /// \brief Return true if this machine model includes an instruction-level
+ /// scheduling model.
+ ///
+ /// This is more detailed than the course grain IssueWidth and default
+ /// latency properties, but separate from the per-cycle itinerary data.
+ bool hasInstrSchedModel() const;
+
+ const MCSchedModel *getMCSchedModel() const { return &SchedModel; }
+
+ /// \brief Return true if this machine model includes cycle-to-cycle itinerary
+ /// data.
+ ///
+ /// This models scheduling at each stage in the processor pipeline.
+ bool hasInstrItineraries() const;
+
+ const InstrItineraryData *getInstrItineraries() const {
+ if (hasInstrItineraries())
+ return &InstrItins;
+ return 0;
+ }
+
+ /// \brief Identify the processor corresponding to the current subtarget.
+ unsigned getProcessorID() const { return SchedModel.getProcessorID(); }
+
+ /// \brief Maximum number of micro-ops that may be scheduled per cycle.
+ unsigned getIssueWidth() const { return SchedModel.IssueWidth; }
+
+ /// \brief Return the number of issue slots required for this MI.
+ unsigned getNumMicroOps(const MachineInstr *MI,
+ const MCSchedClassDesc *SC = 0) const;
+
+ /// \brief Get the number of kinds of resources for this target.
+ unsigned getNumProcResourceKinds() const {
+ return SchedModel.getNumProcResourceKinds();
+ }
+
+ /// \brief Get a processor resource by ID for convenience.
+ const MCProcResourceDesc *getProcResource(unsigned PIdx) const {
+ return SchedModel.getProcResource(PIdx);
+ }
+
+ typedef const MCWriteProcResEntry *ProcResIter;
+
+ // \brief Get an iterator into the processor resources consumed by this
+ // scheduling class.
+ ProcResIter getWriteProcResBegin(const MCSchedClassDesc *SC) const {
+ // The subtarget holds a single resource table for all processors.
+ return STI->getWriteProcResBegin(SC);
+ }
+ ProcResIter getWriteProcResEnd(const MCSchedClassDesc *SC) const {
+ return STI->getWriteProcResEnd(SC);
+ }
+
+ /// \brief Multiply the number of units consumed for a resource by this factor
+ /// to normalize it relative to other resources.
+ unsigned getResourceFactor(unsigned ResIdx) const {
+ return ResourceFactors[ResIdx];
+ }
+
+ /// \brief Multiply number of micro-ops by this factor to normalize it
+ /// relative to other resources.
+ unsigned getMicroOpFactor() const {
+ return MicroOpFactor;
+ }
+
+ /// \brief Multiply cycle count by this factor to normalize it relative to
+ /// other resources. This is the number of resource units per cycle.
+ unsigned getLatencyFactor() const {
+ return ResourceLCM;
+ }
+
+ /// \brief Compute operand latency based on the available machine model.
+ ///
+ /// Computes and return the latency of the given data dependent def and use
+ /// when the operand indices are already known. UseMI may be NULL for an
+ /// unknown user.
+ ///
+ /// FindMin may be set to get the minimum vs. expected latency. Minimum
+ /// latency is used for scheduling groups, while expected latency is for
+ /// instruction cost and critical path.
+ unsigned computeOperandLatency(const MachineInstr *DefMI, unsigned DefOperIdx,
+ const MachineInstr *UseMI, unsigned UseOperIdx,
+ bool FindMin) const;
+
+ /// \brief Compute the instruction latency based on the available machine
+ /// model.
+ ///
+ /// Compute and return the expected latency of this instruction independent of
+ /// a particular use. computeOperandLatency is the prefered API, but this is
+ /// occasionally useful to help estimate instruction cost.
+ unsigned computeInstrLatency(const MachineInstr *MI) const;
+
+ /// \brief Output dependency latency of a pair of defs of the same register.
+ ///
+ /// This is typically one cycle.
+ unsigned computeOutputLatency(const MachineInstr *DefMI, unsigned DefIdx,
+ const MachineInstr *DepMI) const;
+
+private:
+ /// getDefLatency is a helper for computeOperandLatency. Return the
+ /// instruction's latency if operand lookup is not required.
+ /// Otherwise return -1.
+ int getDefLatency(const MachineInstr *DefMI, bool FindMin) const;
+};
+
+} // namespace llvm
+
+#endif
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