llvm-6502/lib/Target/TargetRegisterInfo.cpp
2011-06-28 21:14:33 +00:00

142 lines
4.6 KiB
C++

//===- TargetRegisterInfo.cpp - Target Register Information Implementation ===//
//
// 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 TargetRegisterInfo interface.
//
//===----------------------------------------------------------------------===//
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
TargetRegisterInfo::TargetRegisterInfo(const TargetRegisterInfoDesc *ID,
regclass_iterator RCB, regclass_iterator RCE,
const char *const *subregindexnames)
: InfoDesc(ID), SubRegIndexNames(subregindexnames),
RegClassBegin(RCB), RegClassEnd(RCE) {
}
TargetRegisterInfo::~TargetRegisterInfo() {}
void PrintReg::print(raw_ostream &OS) const {
if (!Reg)
OS << "%noreg";
else if (TargetRegisterInfo::isStackSlot(Reg))
OS << "SS#" << TargetRegisterInfo::stackSlot2Index(Reg);
else if (TargetRegisterInfo::isVirtualRegister(Reg))
OS << "%vreg" << TargetRegisterInfo::virtReg2Index(Reg);
else if (TRI && Reg < TRI->getNumRegs())
OS << '%' << TRI->getName(Reg);
else
OS << "%physreg" << Reg;
if (SubIdx) {
if (TRI)
OS << ':' << TRI->getSubRegIndexName(SubIdx);
else
OS << ":sub(" << SubIdx << ')';
}
}
/// getMinimalPhysRegClass - Returns the Register Class of a physical
/// register of the given type, picking the most sub register class of
/// the right type that contains this physreg.
const TargetRegisterClass *
TargetRegisterInfo::getMinimalPhysRegClass(unsigned reg, EVT VT) const {
assert(isPhysicalRegister(reg) && "reg must be a physical register");
// Pick the most sub register class of the right type that contains
// this physreg.
const TargetRegisterClass* BestRC = 0;
for (regclass_iterator I = regclass_begin(), E = regclass_end(); I != E; ++I){
const TargetRegisterClass* RC = *I;
if ((VT == MVT::Other || RC->hasType(VT)) && RC->contains(reg) &&
(!BestRC || BestRC->hasSubClass(RC)))
BestRC = RC;
}
assert(BestRC && "Couldn't find the register class");
return BestRC;
}
/// getAllocatableSetForRC - Toggle the bits that represent allocatable
/// registers for the specific register class.
static void getAllocatableSetForRC(const MachineFunction &MF,
const TargetRegisterClass *RC, BitVector &R){
ArrayRef<unsigned> Order = RC->getRawAllocationOrder(MF);
for (unsigned i = 0; i != Order.size(); ++i)
R.set(Order[i]);
}
BitVector TargetRegisterInfo::getAllocatableSet(const MachineFunction &MF,
const TargetRegisterClass *RC) const {
BitVector Allocatable(getNumRegs());
if (RC) {
getAllocatableSetForRC(MF, RC, Allocatable);
} else {
for (TargetRegisterInfo::regclass_iterator I = regclass_begin(),
E = regclass_end(); I != E; ++I)
if ((*I)->isAllocatable())
getAllocatableSetForRC(MF, *I, Allocatable);
}
// Mask out the reserved registers
BitVector Reserved = getReservedRegs(MF);
Allocatable &= Reserved.flip();
return Allocatable;
}
const TargetRegisterClass *
llvm::getCommonSubClass(const TargetRegisterClass *A,
const TargetRegisterClass *B) {
// First take care of the trivial cases
if (A == B)
return A;
if (!A || !B)
return 0;
// If B is a subclass of A, it will be handled in the loop below
if (B->hasSubClass(A))
return A;
const TargetRegisterClass *Best = 0;
for (TargetRegisterClass::sc_iterator I = A->subclasses_begin();
const TargetRegisterClass *X = *I; ++I) {
if (X == B)
return B; // B is a subclass of A
// X must be a common subclass of A and B
if (!B->hasSubClass(X))
continue;
// A superclass is definitely better.
if (!Best || Best->hasSuperClass(X)) {
Best = X;
continue;
}
// A subclass is definitely worse
if (Best->hasSubClass(X))
continue;
// Best and *I have no super/sub class relation - pick the larger class, or
// the smaller spill size.
int nb = std::distance(Best->begin(), Best->end());
int ni = std::distance(X->begin(), X->end());
if (ni>nb || (ni==nb && X->getSize() < Best->getSize()))
Best = X;
}
return Best;
}