llvm-6502/lib/CodeGen/RegAllocBase.h
Benjamin Kramer 55c06ae7af Revert "Give internal classes hidden visibility."
It works with clang, but GCC has different rules so we can't make all of those
hidden. This reverts commit r190534.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190536 91177308-0d34-0410-b5e6-96231b3b80d8
2013-09-11 18:05:11 +00:00

109 lines
3.9 KiB
C++

//===-- RegAllocBase.h - basic regalloc interface and driver --*- 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 the RegAllocBase class, which is the skeleton of a basic
// register allocation algorithm and interface for extending it. It provides the
// building blocks on which to construct other experimental allocators and test
// the validity of two principles:
//
// - If virtual and physical register liveness is modeled using intervals, then
// on-the-fly interference checking is cheap. Furthermore, interferences can be
// lazily cached and reused.
//
// - Register allocation complexity, and generated code performance is
// determined by the effectiveness of live range splitting rather than optimal
// coloring.
//
// Following the first principle, interfering checking revolves around the
// LiveIntervalUnion data structure.
//
// To fulfill the second principle, the basic allocator provides a driver for
// incremental splitting. It essentially punts on the problem of register
// coloring, instead driving the assignment of virtual to physical registers by
// the cost of splitting. The basic allocator allows for heuristic reassignment
// of registers, if a more sophisticated allocator chooses to do that.
//
// This framework provides a way to engineer the compile time vs. code
// quality trade-off without relying on a particular theoretical solver.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_REGALLOCBASE
#define LLVM_CODEGEN_REGALLOCBASE
#include "llvm/ADT/OwningPtr.h"
#include "llvm/CodeGen/LiveInterval.h"
#include "llvm/CodeGen/RegisterClassInfo.h"
namespace llvm {
template<typename T> class SmallVectorImpl;
class TargetRegisterInfo;
class VirtRegMap;
class LiveIntervals;
class LiveRegMatrix;
class Spiller;
/// RegAllocBase provides the register allocation driver and interface that can
/// be extended to add interesting heuristics.
///
/// Register allocators must override the selectOrSplit() method to implement
/// live range splitting. They must also override enqueue/dequeue to provide an
/// assignment order.
class RegAllocBase {
protected:
const TargetRegisterInfo *TRI;
MachineRegisterInfo *MRI;
VirtRegMap *VRM;
LiveIntervals *LIS;
LiveRegMatrix *Matrix;
RegisterClassInfo RegClassInfo;
RegAllocBase(): TRI(0), MRI(0), VRM(0), LIS(0), Matrix(0) {}
virtual ~RegAllocBase() {}
// A RegAlloc pass should call this before allocatePhysRegs.
void init(VirtRegMap &vrm, LiveIntervals &lis, LiveRegMatrix &mat);
// The top-level driver. The output is a VirtRegMap that us updated with
// physical register assignments.
void allocatePhysRegs();
// Get a temporary reference to a Spiller instance.
virtual Spiller &spiller() = 0;
/// enqueue - Add VirtReg to the priority queue of unassigned registers.
virtual void enqueue(LiveInterval *LI) = 0;
/// dequeue - Return the next unassigned register, or NULL.
virtual LiveInterval *dequeue() = 0;
// A RegAlloc pass should override this to provide the allocation heuristics.
// Each call must guarantee forward progess by returning an available PhysReg
// or new set of split live virtual registers. It is up to the splitter to
// converge quickly toward fully spilled live ranges.
virtual unsigned selectOrSplit(LiveInterval &VirtReg,
SmallVectorImpl<unsigned> &splitLVRs) = 0;
// Use this group name for NamedRegionTimer.
static const char TimerGroupName[];
public:
/// VerifyEnabled - True when -verify-regalloc is given.
static bool VerifyEnabled;
private:
void seedLiveRegs();
};
} // end namespace llvm
#endif // !defined(LLVM_CODEGEN_REGALLOCBASE)