PIC16MemSelOpt.cpp [plain text]
#define DEBUG_TYPE "pic16-codegen"
#include "PIC16.h"
#include "PIC16ABINames.h"
#include "PIC16InstrInfo.h"
#include "PIC16MCAsmInfo.h"
#include "PIC16TargetMachine.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/GlobalValue.h"
#include "llvm/DerivedTypes.h"
using namespace llvm;
namespace {
struct MemSelOpt : public MachineFunctionPass {
static char ID;
MemSelOpt() : MachineFunctionPass(&ID) {}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addPreservedID(MachineLoopInfoID);
AU.addPreservedID(MachineDominatorsID);
MachineFunctionPass::getAnalysisUsage(AU);
}
virtual bool runOnMachineFunction(MachineFunction &MF);
virtual const char *getPassName() const {
return "PIC16 Memsel Optimizer";
}
bool processBasicBlock(MachineFunction &MF, MachineBasicBlock &MBB);
bool processInstruction(MachineInstr *MI);
private:
const TargetInstrInfo *TII; MachineBasicBlock *MBB; std::string CurBank;
int PageChanged;
};
char MemSelOpt::ID = 0;
}
FunctionPass *llvm::createPIC16MemSelOptimizerPass() {
return new MemSelOpt();
}
bool MemSelOpt::runOnMachineFunction(MachineFunction &MF) {
TII = MF.getTarget().getInstrInfo();
bool Changed = false;
for (MachineFunction::iterator I = MF.begin(), E = MF.end();
I != E; ++I) {
Changed |= processBasicBlock(MF, *I);
}
return Changed;
}
bool MemSelOpt::processBasicBlock(MachineFunction &MF, MachineBasicBlock &BB) {
bool Changed = false;
MBB = &BB;
CurBank="";
PageChanged=0;
MachineBasicBlock::iterator I;
for (I = BB.begin(); I != BB.end(); ++I) {
Changed |= processInstruction(I);
if (PageChanged == 1)
{
if ((I->getOpcode() == PIC16::sublw_3) || (I->getOpcode() == PIC16::sublw_6) || (I->getOpcode() == PIC16::addlwc) || (TII->get(I->getOpcode()).isBranch()))
{
DebugLoc dl = I->getDebugLoc();
BuildMI(*MBB, I, dl, TII->get(PIC16::pagesel)).addExternalSymbol("$");
Changed = true;
PageChanged = 0;
}
}
}
if (PageChanged == 1) {
MachineBasicBlock::iterator J = I;
I--;
const TargetInstrDesc &TID = TII->get(I->getOpcode());
if (! TID.isReturn())
{
DebugLoc dl = I->getDebugLoc();
BuildMI(*MBB, J, dl,
TII->get(PIC16::pagesel)).addExternalSymbol("$");
Changed = true;
PageChanged = 0;
}
}
return Changed;
}
bool MemSelOpt::processInstruction(MachineInstr *MI) {
bool Changed = false;
unsigned NumOperands = MI->getNumOperands();
if (NumOperands == 0) return false;
const TargetInstrDesc &TID = TII->get(MI->getOpcode());
if (!(TID.isBranch() || TID.isCall() || TID.mayLoad() || TID.mayStore()))
return false;
if (TID.isCall()) {
PageChanged = 1;
CurBank = "";
}
int MemOpPos = -1;
int BBOpPos = -1;
for (unsigned i = 0; i < NumOperands; i++) {
MachineOperand Op = MI->getOperand(i);
if (Op.getType() == MachineOperand::MO_GlobalAddress ||
Op.getType() == MachineOperand::MO_ExternalSymbol) {
MemOpPos = i;
}
if (Op.getType() == MachineOperand::MO_MachineBasicBlock) {
BBOpPos = i;
}
}
if ((MemOpPos == -1) &&
(BBOpPos == -1))
return false;
assert ((BBOpPos != MemOpPos) && "operand can only be of one type");
if ((MI->getOpcode() == PIC16::CALL)) {
MachineOperand &MemOp = MI->getOperand(MemOpPos);
DebugLoc dl = MI->getDebugLoc();
BuildMI(*MBB, MI, dl, TII->get(PIC16::pagesel)).addOperand(MemOp);
return true;
}
if (MemOpPos == -1) return Changed;
MachineOperand &Op = MI->getOperand(MemOpPos);
std::string NewBank = CurBank;
bool hasExternalLinkage = false;
if (Op.getType() == MachineOperand::MO_GlobalAddress &&
Op.getGlobal()->getType()->getAddressSpace() == PIC16ISD::RAM_SPACE) {
if (Op.getGlobal()->hasExternalLinkage())
hasExternalLinkage= true;
NewBank = Op.getGlobal()->getSection();
} else if (Op.getType() == MachineOperand::MO_ExternalSymbol) {
std::string Sym = Op.getSymbolName();
NewBank = PAN::getSectionNameForSym(Sym);
}
if (NewBank == PAN::getSharedUDataSectionName())
return Changed;
if (NewBank.compare(CurBank) != 0 || hasExternalLinkage) {
DebugLoc dl = MI->getDebugLoc();
BuildMI(*MBB, MI, dl, TII->get(PIC16::banksel)).
addOperand(Op);
Changed = true;
CurBank = NewBank;
}
return Changed;
}