mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-11-25 20:23:11 +01:00
72 lines
2.5 KiB
C++
72 lines
2.5 KiB
C++
//=- llvm/CodeGen/ScheduleHazardRecognizer.h - Scheduling Support -*- C++ -*-=//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file implements the ScheduleHazardRecognizer class, which implements
|
|
// hazard-avoidance heuristics for scheduling.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef LLVM_CODEGEN_SCHEDULEHAZARDRECOGNIZER_H
|
|
#define LLVM_CODEGEN_SCHEDULEHAZARDRECOGNIZER_H
|
|
|
|
namespace llvm {
|
|
|
|
class SUnit;
|
|
|
|
/// HazardRecognizer - This determines whether or not an instruction can be
|
|
/// issued this cycle, and whether or not a noop needs to be inserted to handle
|
|
/// the hazard.
|
|
class ScheduleHazardRecognizer {
|
|
public:
|
|
virtual ~ScheduleHazardRecognizer();
|
|
|
|
enum HazardType {
|
|
NoHazard, // This instruction can be emitted at this cycle.
|
|
Hazard, // This instruction can't be emitted at this cycle.
|
|
NoopHazard // This instruction can't be emitted, and needs noops.
|
|
};
|
|
|
|
/// getHazardType - Return the hazard type of emitting this node. There are
|
|
/// three possible results. Either:
|
|
/// * NoHazard: it is legal to issue this instruction on this cycle.
|
|
/// * Hazard: issuing this instruction would stall the machine. If some
|
|
/// other instruction is available, issue it first.
|
|
/// * NoopHazard: issuing this instruction would break the program. If
|
|
/// some other instruction can be issued, do so, otherwise issue a noop.
|
|
virtual HazardType getHazardType(SUnit *) {
|
|
return NoHazard;
|
|
}
|
|
|
|
/// Reset - This callback is invoked when a new block of
|
|
/// instructions is about to be schedule. The hazard state should be
|
|
/// set to an initialized state.
|
|
virtual void Reset() {}
|
|
|
|
/// EmitInstruction - This callback is invoked when an instruction is
|
|
/// emitted, to advance the hazard state.
|
|
virtual void EmitInstruction(SUnit *) {}
|
|
|
|
/// AdvanceCycle - This callback is invoked when no instructions can be
|
|
/// issued on this cycle without a hazard. This should increment the
|
|
/// internal state of the hazard recognizer so that previously "Hazard"
|
|
/// instructions will now not be hazards.
|
|
virtual void AdvanceCycle() {}
|
|
|
|
/// EmitNoop - This callback is invoked when a noop was added to the
|
|
/// instruction stream.
|
|
virtual void EmitNoop() {
|
|
// Default implementation: count it as a cycle.
|
|
AdvanceCycle();
|
|
}
|
|
};
|
|
|
|
}
|
|
|
|
#endif
|