llvm-6502/lib/Target/SparcV8/DelaySlotFiller.cpp
2004-04-07 04:05:12 +00:00

81 lines
2.3 KiB
C++

//===-- DelaySlotFiller.cpp - SparcV8 delay slot filler -------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Simple local delay slot filler for SparcV8 machine code
//
//===----------------------------------------------------------------------===//
#include "SparcV8.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "Support/Statistic.h"
using namespace llvm;
namespace {
Statistic<> FilledSlots ("delayslotfiller", "Num. of delay slots filled");
struct Filler : public MachineFunctionPass {
/// Target machine description which we query for reg. names, data
/// layout, etc.
///
TargetMachine &TM;
Filler (TargetMachine &tm) : TM (tm) { }
virtual const char *getPassName () const {
return "SparcV8 Delay Slot Filler";
}
bool runOnMachineBasicBlock (MachineBasicBlock &MBB);
bool runOnMachineFunction (MachineFunction &F) {
bool Changed = false;
for (MachineFunction::iterator FI = F.begin (), FE = F.end ();
FI != FE; ++FI)
Changed |= runOnMachineBasicBlock (*FI);
return Changed;
}
};
} // end of anonymous namespace
/// createSparcV8DelaySlotFillerPass - Returns a pass that fills in delay
/// slots in SparcV8 MachineFunctions
///
FunctionPass *llvm::createSparcV8DelaySlotFillerPass (TargetMachine &tm) {
return new Filler (tm);
}
static bool hasDelaySlot (unsigned Opcode) {
switch (Opcode) {
case V8::CALL:
case V8::RETL:
return true;
default:
return false;
}
}
/// runOnMachineBasicBlock - Fill in delay slots for the given basic block.
/// Currently, we fill delay slots with NOPs. We assume there is only one
/// delay slot per delayed instruction.
///
bool Filler::runOnMachineBasicBlock (MachineBasicBlock &MBB) {
bool Changed = false;
for (MachineBasicBlock::iterator I = MBB.begin (); I != MBB.end (); ++I)
if (hasDelaySlot (I->getOpcode ())) {
MachineBasicBlock::iterator J = I;
++J;
BuildMI (MBB, J, V8::NOP, 0);
++FilledSlots;
Changed = true;
}
return Changed;
}