forked from OSchip/llvm-project
145 lines
5.5 KiB
C++
145 lines
5.5 KiB
C++
//===-- LiveRegMatrix.h - Track register interference ---------*- C++ -*---===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// The LiveRegMatrix analysis pass keeps track of virtual register interference
|
|
// along two dimensions: Slot indexes and register units. The matrix is used by
|
|
// register allocators to ensure that no interfering virtual registers get
|
|
// assigned to overlapping physical registers.
|
|
//
|
|
// Register units are defined in MCRegisterInfo.h, they represent the smallest
|
|
// unit of interference when dealing with overlapping physical registers. The
|
|
// LiveRegMatrix is represented as a LiveIntervalUnion per register unit. When
|
|
// a virtual register is assigned to a physicval register, the live range for
|
|
// the virtual register is inserted into the LiveIntervalUnion for each regunit
|
|
// in the physreg.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef LLVM_CODEGEN_LIVEREGMATRIX_H
|
|
#define LLVM_CODEGEN_LIVEREGMATRIX_H
|
|
|
|
#include "LiveIntervalUnion.h"
|
|
#include "llvm/ADT/BitVector.h"
|
|
#include "llvm/ADT/OwningPtr.h"
|
|
#include "llvm/CodeGen/MachineFunctionPass.h"
|
|
|
|
namespace llvm {
|
|
|
|
class LiveInterval;
|
|
class LiveIntervalAnalysis;
|
|
class MachineRegisterInfo;
|
|
class TargetRegisterInfo;
|
|
class VirtRegMap;
|
|
|
|
class LiveRegMatrix : public MachineFunctionPass {
|
|
const TargetRegisterInfo *TRI;
|
|
MachineRegisterInfo *MRI;
|
|
LiveIntervals *LIS;
|
|
VirtRegMap *VRM;
|
|
|
|
// UserTag changes whenever virtual registers have been modified.
|
|
unsigned UserTag;
|
|
|
|
// The matrix is represented as a LiveIntervalUnion per register unit.
|
|
LiveIntervalUnion::Allocator LIUAlloc;
|
|
LiveIntervalUnion::Array Matrix;
|
|
|
|
// Cached queries per register unit.
|
|
OwningArrayPtr<LiveIntervalUnion::Query> Queries;
|
|
|
|
// Cached register mask interference info.
|
|
unsigned RegMaskTag;
|
|
unsigned RegMaskVirtReg;
|
|
BitVector RegMaskUsable;
|
|
|
|
// MachineFunctionPass boilerplate.
|
|
virtual void getAnalysisUsage(AnalysisUsage&) const;
|
|
virtual bool runOnMachineFunction(MachineFunction&);
|
|
virtual void releaseMemory();
|
|
public:
|
|
static char ID;
|
|
LiveRegMatrix();
|
|
|
|
//===--------------------------------------------------------------------===//
|
|
// High-level interface.
|
|
//===--------------------------------------------------------------------===//
|
|
//
|
|
// Check for interference before assigning virtual registers to physical
|
|
// registers.
|
|
//
|
|
|
|
/// Invalidate cached interference queries after modifying virtual register
|
|
/// live ranges. Interference checks may return stale information unless
|
|
/// caches are invalidated.
|
|
void invalidateVirtRegs() { ++UserTag; }
|
|
|
|
enum InterferenceKind {
|
|
/// No interference, go ahead and assign.
|
|
IK_Free = 0,
|
|
|
|
/// Virtual register interference. There are interfering virtual registers
|
|
/// assigned to PhysReg or its aliases. This interference could be resolved
|
|
/// by unassigning those other virtual registers.
|
|
IK_VirtReg,
|
|
|
|
/// Register unit interference. A fixed live range is in the way, typically
|
|
/// argument registers for a call. This can't be resolved by unassigning
|
|
/// other virtual registers.
|
|
IK_RegUnit,
|
|
|
|
/// RegMask interference. The live range is crossing an instruction with a
|
|
/// regmask operand that doesn't preserve PhysReg. This typically means
|
|
/// VirtReg is live across a call, and PhysReg isn't call-preserved.
|
|
IK_RegMask
|
|
};
|
|
|
|
/// Check for interference before assigning VirtReg to PhysReg.
|
|
/// If this function returns IK_Free, it is legal to assign(VirtReg, PhysReg).
|
|
/// When there is more than one kind of interference, the InterferenceKind
|
|
/// with the highest enum value is returned.
|
|
InterferenceKind checkInterference(LiveInterval &VirtReg, unsigned PhysReg);
|
|
|
|
/// Assign VirtReg to PhysReg.
|
|
/// This will mark VirtReg's live range as occupied in the LiveRegMatrix and
|
|
/// update VirtRegMap. The live range is expected to be available in PhysReg.
|
|
void assign(LiveInterval &VirtReg, unsigned PhysReg);
|
|
|
|
/// Unassign VirtReg from its PhysReg.
|
|
/// Assuming that VirtReg was previously assigned to a PhysReg, this undoes
|
|
/// the assignment and updates VirtRegMap accordingly.
|
|
void unassign(LiveInterval &VirtReg);
|
|
|
|
//===--------------------------------------------------------------------===//
|
|
// Low-level interface.
|
|
//===--------------------------------------------------------------------===//
|
|
//
|
|
// Provide access to the underlying LiveIntervalUnions.
|
|
//
|
|
|
|
/// Check for regmask interference only.
|
|
/// Return true if VirtReg crosses a regmask operand that clobbers PhysReg.
|
|
/// If PhysReg is null, check if VirtReg crosses any regmask operands.
|
|
bool checkRegMaskInterference(LiveInterval &VirtReg, unsigned PhysReg = 0);
|
|
|
|
/// Check for regunit interference only.
|
|
/// Return true if VirtReg overlaps a fixed assignment of one of PhysRegs's
|
|
/// register units.
|
|
bool checkRegUnitInterference(LiveInterval &VirtReg, unsigned PhysReg);
|
|
|
|
/// Query a line of the assigned virtual register matrix directly.
|
|
/// Use MCRegUnitIterator to enumerate all regunits in the desired PhysReg.
|
|
/// This returns a reference to an internal Query data structure that is only
|
|
/// valid until the next query() call.
|
|
LiveIntervalUnion::Query &query(LiveInterval &VirtReg, unsigned RegUnit);
|
|
};
|
|
|
|
} // end namespace llvm
|
|
|
|
#endif // LLVM_CODEGEN_LIVEREGMATRIX_H
|