llvm/lib/Target/TargetInstrInfo.cpp
2011-07-01 17:57:27 +00:00

175 lines
5.8 KiB
C++

//===-- TargetInstrInfo.cpp - Target Instruction Information --------------===//
//
// 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 TargetInstrInfo class.
//
//===----------------------------------------------------------------------===//
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/CodeGen/SelectionDAGNodes.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCInstrItineraries.h"
#include "llvm/Support/ErrorHandling.h"
#include <cctype>
using namespace llvm;
//===----------------------------------------------------------------------===//
// TargetInstrInfo
//===----------------------------------------------------------------------===//
TargetInstrInfo::~TargetInstrInfo() {
}
const TargetRegisterClass*
TargetInstrInfo::getRegClass(const MCInstrDesc &MCID, unsigned OpNum,
const TargetRegisterInfo *TRI) const {
if (OpNum >= MCID.getNumOperands())
return 0;
short RegClass = MCID.OpInfo[OpNum].RegClass;
if (MCID.OpInfo[OpNum].isLookupPtrRegClass())
return TRI->getPointerRegClass(RegClass);
// Instructions like INSERT_SUBREG do not have fixed register classes.
if (RegClass < 0)
return 0;
// Otherwise just look it up normally.
return TRI->getRegClass(RegClass);
}
unsigned
TargetInstrInfo::getNumMicroOps(const InstrItineraryData *ItinData,
const MachineInstr *MI) const {
if (!ItinData || ItinData->isEmpty())
return 1;
unsigned Class = MI->getDesc().getSchedClass();
unsigned UOps = ItinData->Itineraries[Class].NumMicroOps;
if (UOps)
return UOps;
// The # of u-ops is dynamically determined. The specific target should
// override this function to return the right number.
return 1;
}
int
TargetInstrInfo::getOperandLatency(const InstrItineraryData *ItinData,
const MachineInstr *DefMI, unsigned DefIdx,
const MachineInstr *UseMI, unsigned UseIdx) const {
if (!ItinData || ItinData->isEmpty())
return -1;
unsigned DefClass = DefMI->getDesc().getSchedClass();
unsigned UseClass = UseMI->getDesc().getSchedClass();
return ItinData->getOperandLatency(DefClass, DefIdx, UseClass, UseIdx);
}
int
TargetInstrInfo::getOperandLatency(const InstrItineraryData *ItinData,
SDNode *DefNode, unsigned DefIdx,
SDNode *UseNode, unsigned UseIdx) const {
if (!ItinData || ItinData->isEmpty())
return -1;
if (!DefNode->isMachineOpcode())
return -1;
unsigned DefClass = get(DefNode->getMachineOpcode()).getSchedClass();
if (!UseNode->isMachineOpcode())
return ItinData->getOperandCycle(DefClass, DefIdx);
unsigned UseClass = get(UseNode->getMachineOpcode()).getSchedClass();
return ItinData->getOperandLatency(DefClass, DefIdx, UseClass, UseIdx);
}
int TargetInstrInfo::getInstrLatency(const InstrItineraryData *ItinData,
const MachineInstr *MI,
unsigned *PredCost) const {
if (!ItinData || ItinData->isEmpty())
return 1;
return ItinData->getStageLatency(MI->getDesc().getSchedClass());
}
int TargetInstrInfo::getInstrLatency(const InstrItineraryData *ItinData,
SDNode *N) const {
if (!ItinData || ItinData->isEmpty())
return 1;
if (!N->isMachineOpcode())
return 1;
return ItinData->getStageLatency(get(N->getMachineOpcode()).getSchedClass());
}
bool TargetInstrInfo::hasLowDefLatency(const InstrItineraryData *ItinData,
const MachineInstr *DefMI,
unsigned DefIdx) const {
if (!ItinData || ItinData->isEmpty())
return false;
unsigned DefClass = DefMI->getDesc().getSchedClass();
int DefCycle = ItinData->getOperandCycle(DefClass, DefIdx);
return (DefCycle != -1 && DefCycle <= 1);
}
/// insertNoop - Insert a noop into the instruction stream at the specified
/// point.
void TargetInstrInfo::insertNoop(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI) const {
llvm_unreachable("Target didn't implement insertNoop!");
}
bool TargetInstrInfo::isUnpredicatedTerminator(const MachineInstr *MI) const {
const MCInstrDesc &MCID = MI->getDesc();
if (!MCID.isTerminator()) return false;
// Conditional branch is a special case.
if (MCID.isBranch() && !MCID.isBarrier())
return true;
if (!MCID.isPredicable())
return true;
return !isPredicated(MI);
}
/// Measure the specified inline asm to determine an approximation of its
/// length.
/// Comments (which run till the next SeparatorString or newline) do not
/// count as an instruction.
/// Any other non-whitespace text is considered an instruction, with
/// multiple instructions separated by SeparatorString or newlines.
/// Variable-length instructions are not handled here; this function
/// may be overloaded in the target code to do that.
unsigned TargetInstrInfo::getInlineAsmLength(const char *Str,
const MCAsmInfo &MAI) const {
// Count the number of instructions in the asm.
bool atInsnStart = true;
unsigned Length = 0;
for (; *Str; ++Str) {
if (*Str == '\n' || strncmp(Str, MAI.getSeparatorString(),
strlen(MAI.getSeparatorString())) == 0)
atInsnStart = true;
if (atInsnStart && !std::isspace(*Str)) {
Length += MAI.getMaxInstLength();
atInsnStart = false;
}
if (atInsnStart && strncmp(Str, MAI.getCommentString(),
strlen(MAI.getCommentString())) == 0)
atInsnStart = false;
}
return Length;
}