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llvm-6502/lib/Target/XCore/XCoreInstrInfo.cpp
Bill Wendling 587daedce2 Change MachineInstrBuilder::addReg() to take a flag instead of a list of 
booleans. This gives a better indication of what the "addReg()" is
doing. Remembering what all of those booleans mean isn't easy, especially if you
aren't spending all of your time in that code.

I took Jakob's suggestion and made it illegal to pass in "true" for the
flag. This should hopefully prevent any unintended misuse of this (by reverting
to the old way of using addReg()).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71722 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-13 21:33:08 +00:00

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//===- XCoreInstrInfo.cpp - XCore Instruction Information -------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the XCore implementation of the TargetInstrInfo class.
//
//===----------------------------------------------------------------------===//
#include "XCoreMachineFunctionInfo.h"
#include "XCoreInstrInfo.h"
#include "XCore.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineLocation.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "XCoreGenInstrInfo.inc"
#include "llvm/Support/Debug.h"
namespace llvm {
namespace XCore {
// XCore Condition Codes
enum CondCode {
COND_TRUE,
COND_FALSE,
COND_INVALID
};
}
}
using namespace llvm;
XCoreInstrInfo::XCoreInstrInfo(void)
: TargetInstrInfoImpl(XCoreInsts, array_lengthof(XCoreInsts)),
RI(*this) {
}
static bool isZeroImm(const MachineOperand &op) {
return op.isImm() && op.getImm() == 0;
}
/// Return true if the instruction is a register to register move and
/// leave the source and dest operands in the passed parameters.
///
bool XCoreInstrInfo::isMoveInstr(const MachineInstr &MI,
unsigned &SrcReg, unsigned &DstReg,
unsigned &SrcSR, unsigned &DstSR) const {
SrcSR = DstSR = 0; // No sub-registers.
// We look for 4 kinds of patterns here:
// add dst, src, 0
// sub dst, src, 0
// or dst, src, src
// and dst, src, src
if ((MI.getOpcode() == XCore::ADD_2rus || MI.getOpcode() == XCore::SUB_2rus)
&& isZeroImm(MI.getOperand(2))) {
DstReg = MI.getOperand(0).getReg();
SrcReg = MI.getOperand(1).getReg();
return true;
} else if ((MI.getOpcode() == XCore::OR_3r || MI.getOpcode() == XCore::AND_3r)
&& MI.getOperand(1).getReg() == MI.getOperand(2).getReg()) {
DstReg = MI.getOperand(0).getReg();
SrcReg = MI.getOperand(1).getReg();
return true;
}
return false;
}
/// isLoadFromStackSlot - If the specified machine instruction is a direct
/// load from a stack slot, return the virtual or physical register number of
/// the destination along with the FrameIndex of the loaded stack slot. If
/// not, return 0. This predicate must return 0 if the instruction has
/// any side effects other than loading from the stack slot.
unsigned
XCoreInstrInfo::isLoadFromStackSlot(const MachineInstr *MI, int &FrameIndex) const{
int Opcode = MI->getOpcode();
if (Opcode == XCore::LDWFI)
{
if ((MI->getOperand(1).isFI()) && // is a stack slot
(MI->getOperand(2).isImm()) && // the imm is zero
(isZeroImm(MI->getOperand(2))))
{
FrameIndex = MI->getOperand(1).getIndex();
return MI->getOperand(0).getReg();
}
}
return 0;
}
/// isStoreToStackSlot - If the specified machine instruction is a direct
/// store to a stack slot, return the virtual or physical register number of
/// the source reg along with the FrameIndex of the loaded stack slot. If
/// not, return 0. This predicate must return 0 if the instruction has
/// any side effects other than storing to the stack slot.
unsigned
XCoreInstrInfo::isStoreToStackSlot(const MachineInstr *MI,
int &FrameIndex) const {
int Opcode = MI->getOpcode();
if (Opcode == XCore::STWFI)
{
if ((MI->getOperand(1).isFI()) && // is a stack slot
(MI->getOperand(2).isImm()) && // the imm is zero
(isZeroImm(MI->getOperand(2))))
{
FrameIndex = MI->getOperand(1).getIndex();
return MI->getOperand(0).getReg();
}
}
return 0;
}
/// isInvariantLoad - Return true if the specified instruction (which is marked
/// mayLoad) is loading from a location whose value is invariant across the
/// function. For example, loading a value from the constant pool or from
/// from the argument area of a function if it does not change. This should
/// only return true of *all* loads the instruction does are invariant (if it
/// does multiple loads).
bool
XCoreInstrInfo::isInvariantLoad(const MachineInstr *MI) const {
// Loads from constants pools and loads from invariant argument slots are
// invariant
int Opcode = MI->getOpcode();
if (Opcode == XCore::LDWCP_ru6 || Opcode == XCore::LDWCP_lru6) {
return MI->getOperand(1).isCPI();
}
int FrameIndex;
if (isLoadFromStackSlot(MI, FrameIndex)) {
const MachineFrameInfo &MFI =
*MI->getParent()->getParent()->getFrameInfo();
return MFI.isFixedObjectIndex(FrameIndex) &&
MFI.isImmutableObjectIndex(FrameIndex);
}
return false;
}
//===----------------------------------------------------------------------===//
// Branch Analysis
//===----------------------------------------------------------------------===//
static inline bool IsBRU(unsigned BrOpc) {
return BrOpc == XCore::BRFU_u6
|| BrOpc == XCore::BRFU_lu6
|| BrOpc == XCore::BRBU_u6
|| BrOpc == XCore::BRBU_lu6;
}
static inline bool IsBRT(unsigned BrOpc) {
return BrOpc == XCore::BRFT_ru6
|| BrOpc == XCore::BRFT_lru6
|| BrOpc == XCore::BRBT_ru6
|| BrOpc == XCore::BRBT_lru6;
}
static inline bool IsBRF(unsigned BrOpc) {
return BrOpc == XCore::BRFF_ru6
|| BrOpc == XCore::BRFF_lru6
|| BrOpc == XCore::BRBF_ru6
|| BrOpc == XCore::BRBF_lru6;
}
static inline bool IsCondBranch(unsigned BrOpc) {
return IsBRF(BrOpc) || IsBRT(BrOpc);
}
/// GetCondFromBranchOpc - Return the XCore CC that matches
/// the correspondent Branch instruction opcode.
static XCore::CondCode GetCondFromBranchOpc(unsigned BrOpc)
{
if (IsBRT(BrOpc)) {
return XCore::COND_TRUE;
} else if (IsBRF(BrOpc)) {
return XCore::COND_FALSE;
} else {
return XCore::COND_INVALID;
}
}
/// GetCondBranchFromCond - Return the Branch instruction
/// opcode that matches the cc.
static inline unsigned GetCondBranchFromCond(XCore::CondCode CC)
{
switch (CC) {
default: assert(0 && "Illegal condition code!");
case XCore::COND_TRUE : return XCore::BRFT_lru6;
case XCore::COND_FALSE : return XCore::BRFF_lru6;
}
}
/// GetOppositeBranchCondition - Return the inverse of the specified
/// condition, e.g. turning COND_E to COND_NE.
static inline XCore::CondCode GetOppositeBranchCondition(XCore::CondCode CC)
{
switch (CC) {
default: assert(0 && "Illegal condition code!");
case XCore::COND_TRUE : return XCore::COND_FALSE;
case XCore::COND_FALSE : return XCore::COND_TRUE;
}
}
/// AnalyzeBranch - Analyze the branching code at the end of MBB, returning
/// true if it cannot be understood (e.g. it's a switch dispatch or isn't
/// implemented for a target). Upon success, this returns false and returns
/// with the following information in various cases:
///
/// 1. If this block ends with no branches (it just falls through to its succ)
/// just return false, leaving TBB/FBB null.
/// 2. If this block ends with only an unconditional branch, it sets TBB to be
/// the destination block.
/// 3. If this block ends with an conditional branch and it falls through to
/// an successor block, it sets TBB to be the branch destination block and a
/// list of operands that evaluate the condition. These
/// operands can be passed to other TargetInstrInfo methods to create new
/// branches.
/// 4. If this block ends with an conditional branch and an unconditional
/// block, it returns the 'true' destination in TBB, the 'false' destination
/// in FBB, and a list of operands that evaluate the condition. These
/// operands can be passed to other TargetInstrInfo methods to create new
/// branches.
///
/// Note that RemoveBranch and InsertBranch must be implemented to support
/// cases where this method returns success.
///
bool
XCoreInstrInfo::AnalyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,
MachineBasicBlock *&FBB,
SmallVectorImpl<MachineOperand> &Cond,
bool AllowModify) const {
// If the block has no terminators, it just falls into the block after it.
MachineBasicBlock::iterator I = MBB.end();
if (I == MBB.begin() || !isUnpredicatedTerminator(--I))
return false;
// Get the last instruction in the block.
MachineInstr *LastInst = I;
// If there is only one terminator instruction, process it.
if (I == MBB.begin() || !isUnpredicatedTerminator(--I)) {
if (IsBRU(LastInst->getOpcode())) {
TBB = LastInst->getOperand(0).getMBB();
return false;
}
XCore::CondCode BranchCode = GetCondFromBranchOpc(LastInst->getOpcode());
if (BranchCode == XCore::COND_INVALID)
return true; // Can't handle indirect branch.
// Conditional branch
// Block ends with fall-through condbranch.
TBB = LastInst->getOperand(1).getMBB();
Cond.push_back(MachineOperand::CreateImm(BranchCode));
Cond.push_back(LastInst->getOperand(0));
return false;
}
// Get the instruction before it if it's a terminator.
MachineInstr *SecondLastInst = I;
// If there are three terminators, we don't know what sort of block this is.
if (SecondLastInst && I != MBB.begin() &&
isUnpredicatedTerminator(--I))
return true;
unsigned SecondLastOpc = SecondLastInst->getOpcode();
XCore::CondCode BranchCode = GetCondFromBranchOpc(SecondLastOpc);
// If the block ends with conditional branch followed by unconditional,
// handle it.
if (BranchCode != XCore::COND_INVALID
&& IsBRU(LastInst->getOpcode())) {
TBB = SecondLastInst->getOperand(1).getMBB();
Cond.push_back(MachineOperand::CreateImm(BranchCode));
Cond.push_back(SecondLastInst->getOperand(0));
FBB = LastInst->getOperand(0).getMBB();
return false;
}
// If the block ends with two unconditional branches, handle it. The second
// one is not executed, so remove it.
if (IsBRU(SecondLastInst->getOpcode()) &&
IsBRU(LastInst->getOpcode())) {
TBB = SecondLastInst->getOperand(0).getMBB();
I = LastInst;
if (AllowModify)
I->eraseFromParent();
return false;
}
// Otherwise, can't handle this.
return true;
}
unsigned
XCoreInstrInfo::InsertBranch(MachineBasicBlock &MBB,MachineBasicBlock *TBB,
MachineBasicBlock *FBB,
const SmallVectorImpl<MachineOperand> &Cond)const{
// FIXME there should probably be a DebugLoc argument here
DebugLoc dl = DebugLoc::getUnknownLoc();
// Shouldn't be a fall through.
assert(TBB && "InsertBranch must not be told to insert a fallthrough");
assert((Cond.size() == 2 || Cond.size() == 0) &&
"Unexpected number of components!");
if (FBB == 0) { // One way branch.
if (Cond.empty()) {
// Unconditional branch
BuildMI(&MBB, dl, get(XCore::BRFU_lu6)).addMBB(TBB);
} else {
// Conditional branch.
unsigned Opc = GetCondBranchFromCond((XCore::CondCode)Cond[0].getImm());
BuildMI(&MBB, dl, get(Opc)).addReg(Cond[1].getReg())
.addMBB(TBB);
}
return 1;
}
// Two-way Conditional branch.
assert(Cond.size() == 2 && "Unexpected number of components!");
unsigned Opc = GetCondBranchFromCond((XCore::CondCode)Cond[0].getImm());
BuildMI(&MBB, dl, get(Opc)).addReg(Cond[1].getReg())
.addMBB(TBB);
BuildMI(&MBB, dl, get(XCore::BRFU_lu6)).addMBB(FBB);
return 2;
}
unsigned
XCoreInstrInfo::RemoveBranch(MachineBasicBlock &MBB) const {
MachineBasicBlock::iterator I = MBB.end();
if (I == MBB.begin()) return 0;
--I;
if (!IsBRU(I->getOpcode()) && !IsCondBranch(I->getOpcode()))
return 0;
// Remove the branch.
I->eraseFromParent();
I = MBB.end();
if (I == MBB.begin()) return 1;
--I;
if (!IsCondBranch(I->getOpcode()))
return 1;
// Remove the branch.
I->eraseFromParent();
return 2;
}
bool XCoreInstrInfo::copyRegToReg(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I,
unsigned DestReg, unsigned SrcReg,
const TargetRegisterClass *DestRC,
const TargetRegisterClass *SrcRC) const {
DebugLoc DL = DebugLoc::getUnknownLoc();
if (I != MBB.end()) DL = I->getDebugLoc();
if (DestRC == SrcRC) {
if (DestRC == XCore::GRRegsRegisterClass) {
BuildMI(MBB, I, DL, get(XCore::ADD_2rus), DestReg)
.addReg(SrcReg)
.addImm(0);
return true;
} else {
return false;
}
}
if (SrcRC == XCore::RRegsRegisterClass && SrcReg == XCore::SP &&
DestRC == XCore::GRRegsRegisterClass) {
BuildMI(MBB, I, DL, get(XCore::LDAWSP_ru6), DestReg)
.addImm(0);
return true;
}
if (DestRC == XCore::RRegsRegisterClass && DestReg == XCore::SP &&
SrcRC == XCore::GRRegsRegisterClass) {
BuildMI(MBB, I, DL, get(XCore::SETSP_1r))
.addReg(SrcReg);
return true;
}
return false;
}
void XCoreInstrInfo::storeRegToStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I,
unsigned SrcReg, bool isKill,
int FrameIndex,
const TargetRegisterClass *RC) const
{
DebugLoc DL = DebugLoc::getUnknownLoc();
if (I != MBB.end()) DL = I->getDebugLoc();
BuildMI(MBB, I, DL, get(XCore::STWFI))
.addReg(SrcReg, getKillRegState(isKill))
.addFrameIndex(FrameIndex)
.addImm(0);
}
void XCoreInstrInfo::storeRegToAddr(MachineFunction &MF, unsigned SrcReg,
bool isKill, SmallVectorImpl<MachineOperand> &Addr,
const TargetRegisterClass *RC,
SmallVectorImpl<MachineInstr*> &NewMIs) const
{
assert(0 && "unimplemented\n");
}
void XCoreInstrInfo::loadRegFromStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I,
unsigned DestReg, int FrameIndex,
const TargetRegisterClass *RC) const
{
DebugLoc DL = DebugLoc::getUnknownLoc();
if (I != MBB.end()) DL = I->getDebugLoc();
BuildMI(MBB, I, DL, get(XCore::LDWFI), DestReg)
.addFrameIndex(FrameIndex)
.addImm(0);
}
void XCoreInstrInfo::loadRegFromAddr(MachineFunction &MF, unsigned DestReg,
SmallVectorImpl<MachineOperand> &Addr,
const TargetRegisterClass *RC,
SmallVectorImpl<MachineInstr*> &NewMIs) const
{
assert(0 && "unimplemented\n");
}
bool XCoreInstrInfo::spillCalleeSavedRegisters(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
const std::vector<CalleeSavedInfo> &CSI) const
{
if (CSI.empty()) {
return true;
}
MachineFunction *MF = MBB.getParent();
const MachineFrameInfo *MFI = MF->getFrameInfo();
MachineModuleInfo *MMI = MFI->getMachineModuleInfo();
XCoreFunctionInfo *XFI = MF->getInfo<XCoreFunctionInfo>();
bool emitFrameMoves = XCoreRegisterInfo::needsFrameMoves(*MF);
DebugLoc DL = DebugLoc::getUnknownLoc();
if (MI != MBB.end()) DL = MI->getDebugLoc();
for (std::vector<CalleeSavedInfo>::const_iterator it = CSI.begin();
it != CSI.end(); ++it) {
// Add the callee-saved register as live-in. It's killed at the spill.
MBB.addLiveIn(it->getReg());
storeRegToStackSlot(MBB, MI, it->getReg(), true,
it->getFrameIdx(), it->getRegClass());
if (emitFrameMoves) {
unsigned SaveLabelId = MMI->NextLabelID();
BuildMI(MBB, MI, DL, get(XCore::DBG_LABEL)).addImm(SaveLabelId);
XFI->getSpillLabels().push_back(
std::pair<unsigned, CalleeSavedInfo>(SaveLabelId, *it));
}
}
return true;
}
bool XCoreInstrInfo::restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
const std::vector<CalleeSavedInfo> &CSI) const
{
bool AtStart = MI == MBB.begin();
MachineBasicBlock::iterator BeforeI = MI;
if (!AtStart)
--BeforeI;
for (std::vector<CalleeSavedInfo>::const_iterator it = CSI.begin();
it != CSI.end(); ++it) {
loadRegFromStackSlot(MBB, MI, it->getReg(),
it->getFrameIdx(),
it->getRegClass());
assert(MI != MBB.begin() &&
"loadRegFromStackSlot didn't insert any code!");
// Insert in reverse order. loadRegFromStackSlot can insert multiple
// instructions.
if (AtStart)
MI = MBB.begin();
else {
MI = BeforeI;
++MI;
}
}
return true;
}
/// BlockHasNoFallThrough - Analyse if MachineBasicBlock does not
/// fall-through into its successor block.
bool XCoreInstrInfo::
BlockHasNoFallThrough(const MachineBasicBlock &MBB) const
{
if (MBB.empty()) return false;
switch (MBB.back().getOpcode()) {
case XCore::RETSP_u6: // Return.
case XCore::RETSP_lu6:
case XCore::BAU_1r: // Indirect branch.
case XCore::BRFU_u6: // Uncond branch.
case XCore::BRFU_lu6:
case XCore::BRBU_u6:
case XCore::BRBU_lu6:
return true;
default: return false;
}
}
/// ReverseBranchCondition - Return the inverse opcode of the
/// specified Branch instruction.
bool XCoreInstrInfo::
ReverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const
{
assert((Cond.size() == 2) &&
"Invalid XCore branch condition!");
Cond[0].setImm(GetOppositeBranchCondition((XCore::CondCode)Cond[0].getImm()));
return false;
}
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