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llvm-6502/lib/Target/Sparc/SparcInstrInfo.cpp
Rafael Espindola 3f0ce4fa18 Fix a lot of confusion around inserting nops on empty functions. 
On MachO, and MachO only, we cannot have a truly empty function since that
breaks the linker logic for atomizing the section.

When we are emitting a frame pointer, the presence of an unreachable will
create a cfi instruction pointing past the last instruction. This is perfectly
fine. The FDE information encodes the pc range it applies to. If some tool
cannot handle this, we should explicitly say which bug we are working around
and only work around it when it is actually relevant (not for ELF for example).

Given the unreachable we could omit the .cfi_def_cfa_register, but then
again, we could also omit the entire function prologue if we wanted to.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217801 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-15 18:32:58 +00:00

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//===-- SparcInstrInfo.cpp - Sparc 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 contains the Sparc implementation of the TargetInstrInfo class.
//
//===----------------------------------------------------------------------===//
#include "SparcInstrInfo.h"
#include "Sparc.h"
#include "SparcMachineFunctionInfo.h"
#include "SparcSubtarget.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineMemOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/TargetRegistry.h"
using namespace llvm;
#define GET_INSTRINFO_CTOR_DTOR
#include "SparcGenInstrInfo.inc"
// Pin the vtable to this file.
void SparcInstrInfo::anchor() {}
SparcInstrInfo::SparcInstrInfo(SparcSubtarget &ST)
: SparcGenInstrInfo(SP::ADJCALLSTACKDOWN, SP::ADJCALLSTACKUP),
RI(ST), Subtarget(ST) {
}
/// 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 SparcInstrInfo::isLoadFromStackSlot(const MachineInstr *MI,
int &FrameIndex) const {
if (MI->getOpcode() == SP::LDri ||
MI->getOpcode() == SP::LDXri ||
MI->getOpcode() == SP::LDFri ||
MI->getOpcode() == SP::LDDFri ||
MI->getOpcode() == SP::LDQFri) {
if (MI->getOperand(1).isFI() && MI->getOperand(2).isImm() &&
MI->getOperand(2).getImm() == 0) {
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 SparcInstrInfo::isStoreToStackSlot(const MachineInstr *MI,
int &FrameIndex) const {
if (MI->getOpcode() == SP::STri ||
MI->getOpcode() == SP::STXri ||
MI->getOpcode() == SP::STFri ||
MI->getOpcode() == SP::STDFri ||
MI->getOpcode() == SP::STQFri) {
if (MI->getOperand(0).isFI() && MI->getOperand(1).isImm() &&
MI->getOperand(1).getImm() == 0) {
FrameIndex = MI->getOperand(0).getIndex();
return MI->getOperand(2).getReg();
}
}
return 0;
}
static bool IsIntegerCC(unsigned CC)
{
return (CC <= SPCC::ICC_VC);
}
static SPCC::CondCodes GetOppositeBranchCondition(SPCC::CondCodes CC)
{
switch(CC) {
case SPCC::ICC_A: return SPCC::ICC_N;
case SPCC::ICC_N: return SPCC::ICC_A;
case SPCC::ICC_NE: return SPCC::ICC_E;
case SPCC::ICC_E: return SPCC::ICC_NE;
case SPCC::ICC_G: return SPCC::ICC_LE;
case SPCC::ICC_LE: return SPCC::ICC_G;
case SPCC::ICC_GE: return SPCC::ICC_L;
case SPCC::ICC_L: return SPCC::ICC_GE;
case SPCC::ICC_GU: return SPCC::ICC_LEU;
case SPCC::ICC_LEU: return SPCC::ICC_GU;
case SPCC::ICC_CC: return SPCC::ICC_CS;
case SPCC::ICC_CS: return SPCC::ICC_CC;
case SPCC::ICC_POS: return SPCC::ICC_NEG;
case SPCC::ICC_NEG: return SPCC::ICC_POS;
case SPCC::ICC_VC: return SPCC::ICC_VS;
case SPCC::ICC_VS: return SPCC::ICC_VC;
case SPCC::FCC_A: return SPCC::FCC_N;
case SPCC::FCC_N: return SPCC::FCC_A;
case SPCC::FCC_U: return SPCC::FCC_O;
case SPCC::FCC_O: return SPCC::FCC_U;
case SPCC::FCC_G: return SPCC::FCC_ULE;
case SPCC::FCC_LE: return SPCC::FCC_UG;
case SPCC::FCC_UG: return SPCC::FCC_LE;
case SPCC::FCC_ULE: return SPCC::FCC_G;
case SPCC::FCC_L: return SPCC::FCC_UGE;
case SPCC::FCC_GE: return SPCC::FCC_UL;
case SPCC::FCC_UL: return SPCC::FCC_GE;
case SPCC::FCC_UGE: return SPCC::FCC_L;
case SPCC::FCC_LG: return SPCC::FCC_UE;
case SPCC::FCC_UE: return SPCC::FCC_LG;
case SPCC::FCC_NE: return SPCC::FCC_E;
case SPCC::FCC_E: return SPCC::FCC_NE;
}
llvm_unreachable("Invalid cond code");
}
bool SparcInstrInfo::AnalyzeBranch(MachineBasicBlock &MBB,
MachineBasicBlock *&TBB,
MachineBasicBlock *&FBB,
SmallVectorImpl<MachineOperand> &Cond,
bool AllowModify) const
{
MachineBasicBlock::iterator I = MBB.end();
MachineBasicBlock::iterator UnCondBrIter = MBB.end();
while (I != MBB.begin()) {
--I;
if (I->isDebugValue())
continue;
// When we see a non-terminator, we are done.
if (!isUnpredicatedTerminator(I))
break;
// Terminator is not a branch.
if (!I->isBranch())
return true;
// Handle Unconditional branches.
if (I->getOpcode() == SP::BA) {
UnCondBrIter = I;
if (!AllowModify) {
TBB = I->getOperand(0).getMBB();
continue;
}
while (std::next(I) != MBB.end())
std::next(I)->eraseFromParent();
Cond.clear();
FBB = nullptr;
if (MBB.isLayoutSuccessor(I->getOperand(0).getMBB())) {
TBB = nullptr;
I->eraseFromParent();
I = MBB.end();
UnCondBrIter = MBB.end();
continue;
}
TBB = I->getOperand(0).getMBB();
continue;
}
unsigned Opcode = I->getOpcode();
if (Opcode != SP::BCOND && Opcode != SP::FBCOND)
return true; // Unknown Opcode.
SPCC::CondCodes BranchCode = (SPCC::CondCodes)I->getOperand(1).getImm();
if (Cond.empty()) {
MachineBasicBlock *TargetBB = I->getOperand(0).getMBB();
if (AllowModify && UnCondBrIter != MBB.end() &&
MBB.isLayoutSuccessor(TargetBB)) {
// Transform the code
//
// brCC L1
// ba L2
// L1:
// ..
// L2:
//
// into
//
// brnCC L2
// L1:
// ...
// L2:
//
BranchCode = GetOppositeBranchCondition(BranchCode);
MachineBasicBlock::iterator OldInst = I;
BuildMI(MBB, UnCondBrIter, MBB.findDebugLoc(I), get(Opcode))
.addMBB(UnCondBrIter->getOperand(0).getMBB()).addImm(BranchCode);
BuildMI(MBB, UnCondBrIter, MBB.findDebugLoc(I), get(SP::BA))
.addMBB(TargetBB);
OldInst->eraseFromParent();
UnCondBrIter->eraseFromParent();
UnCondBrIter = MBB.end();
I = MBB.end();
continue;
}
FBB = TBB;
TBB = I->getOperand(0).getMBB();
Cond.push_back(MachineOperand::CreateImm(BranchCode));
continue;
}
// FIXME: Handle subsequent conditional branches.
// For now, we can't handle multiple conditional branches.
return true;
}
return false;
}
unsigned
SparcInstrInfo::InsertBranch(MachineBasicBlock &MBB,MachineBasicBlock *TBB,
MachineBasicBlock *FBB,
const SmallVectorImpl<MachineOperand> &Cond,
DebugLoc DL) const {
assert(TBB && "InsertBranch must not be told to insert a fallthrough");
assert((Cond.size() == 1 || Cond.size() == 0) &&
"Sparc branch conditions should have one component!");
if (Cond.empty()) {
assert(!FBB && "Unconditional branch with multiple successors!");
BuildMI(&MBB, DL, get(SP::BA)).addMBB(TBB);
return 1;
}
// Conditional branch
unsigned CC = Cond[0].getImm();
if (IsIntegerCC(CC))
BuildMI(&MBB, DL, get(SP::BCOND)).addMBB(TBB).addImm(CC);
else
BuildMI(&MBB, DL, get(SP::FBCOND)).addMBB(TBB).addImm(CC);
if (!FBB)
return 1;
BuildMI(&MBB, DL, get(SP::BA)).addMBB(FBB);
return 2;
}
unsigned SparcInstrInfo::RemoveBranch(MachineBasicBlock &MBB) const
{
MachineBasicBlock::iterator I = MBB.end();
unsigned Count = 0;
while (I != MBB.begin()) {
--I;
if (I->isDebugValue())
continue;
if (I->getOpcode() != SP::BA
&& I->getOpcode() != SP::BCOND
&& I->getOpcode() != SP::FBCOND)
break; // Not a branch
I->eraseFromParent();
I = MBB.end();
++Count;
}
return Count;
}
void SparcInstrInfo::copyPhysReg(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I, DebugLoc DL,
unsigned DestReg, unsigned SrcReg,
bool KillSrc) const {
unsigned numSubRegs = 0;
unsigned movOpc = 0;
const unsigned *subRegIdx = nullptr;
const unsigned DFP_FP_SubRegsIdx[] = { SP::sub_even, SP::sub_odd };
const unsigned QFP_DFP_SubRegsIdx[] = { SP::sub_even64, SP::sub_odd64 };
const unsigned QFP_FP_SubRegsIdx[] = { SP::sub_even, SP::sub_odd,
SP::sub_odd64_then_sub_even,
SP::sub_odd64_then_sub_odd };
if (SP::IntRegsRegClass.contains(DestReg, SrcReg))
BuildMI(MBB, I, DL, get(SP::ORrr), DestReg).addReg(SP::G0)
.addReg(SrcReg, getKillRegState(KillSrc));
else if (SP::FPRegsRegClass.contains(DestReg, SrcReg))
BuildMI(MBB, I, DL, get(SP::FMOVS), DestReg)
.addReg(SrcReg, getKillRegState(KillSrc));
else if (SP::DFPRegsRegClass.contains(DestReg, SrcReg)) {
if (Subtarget.isV9()) {
BuildMI(MBB, I, DL, get(SP::FMOVD), DestReg)
.addReg(SrcReg, getKillRegState(KillSrc));
} else {
// Use two FMOVS instructions.
subRegIdx = DFP_FP_SubRegsIdx;
numSubRegs = 2;
movOpc = SP::FMOVS;
}
} else if (SP::QFPRegsRegClass.contains(DestReg, SrcReg)) {
if (Subtarget.isV9()) {
if (Subtarget.hasHardQuad()) {
BuildMI(MBB, I, DL, get(SP::FMOVQ), DestReg)
.addReg(SrcReg, getKillRegState(KillSrc));
} else {
// Use two FMOVD instructions.
subRegIdx = QFP_DFP_SubRegsIdx;
numSubRegs = 2;
movOpc = SP::FMOVD;
}
} else {
// Use four FMOVS instructions.
subRegIdx = QFP_FP_SubRegsIdx;
numSubRegs = 4;
movOpc = SP::FMOVS;
}
} else
llvm_unreachable("Impossible reg-to-reg copy");
if (numSubRegs == 0 || subRegIdx == nullptr || movOpc == 0)
return;
const TargetRegisterInfo *TRI = &getRegisterInfo();
MachineInstr *MovMI = nullptr;
for (unsigned i = 0; i != numSubRegs; ++i) {
unsigned Dst = TRI->getSubReg(DestReg, subRegIdx[i]);
unsigned Src = TRI->getSubReg(SrcReg, subRegIdx[i]);
assert(Dst && Src && "Bad sub-register");
MovMI = BuildMI(MBB, I, DL, get(movOpc), Dst).addReg(Src);
}
// Add implicit super-register defs and kills to the last MovMI.
MovMI->addRegisterDefined(DestReg, TRI);
if (KillSrc)
MovMI->addRegisterKilled(SrcReg, TRI);
}
void SparcInstrInfo::
storeRegToStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
unsigned SrcReg, bool isKill, int FI,
const TargetRegisterClass *RC,
const TargetRegisterInfo *TRI) const {
DebugLoc DL;
if (I != MBB.end()) DL = I->getDebugLoc();
MachineFunction *MF = MBB.getParent();
const MachineFrameInfo &MFI = *MF->getFrameInfo();
MachineMemOperand *MMO =
MF->getMachineMemOperand(MachinePointerInfo::getFixedStack(FI),
MachineMemOperand::MOStore,
MFI.getObjectSize(FI),
MFI.getObjectAlignment(FI));
// On the order of operands here: think "[FrameIdx + 0] = SrcReg".
if (RC == &SP::I64RegsRegClass)
BuildMI(MBB, I, DL, get(SP::STXri)).addFrameIndex(FI).addImm(0)
.addReg(SrcReg, getKillRegState(isKill)).addMemOperand(MMO);
else if (RC == &SP::IntRegsRegClass)
BuildMI(MBB, I, DL, get(SP::STri)).addFrameIndex(FI).addImm(0)
.addReg(SrcReg, getKillRegState(isKill)).addMemOperand(MMO);
else if (RC == &SP::FPRegsRegClass)
BuildMI(MBB, I, DL, get(SP::STFri)).addFrameIndex(FI).addImm(0)
.addReg(SrcReg, getKillRegState(isKill)).addMemOperand(MMO);
else if (SP::DFPRegsRegClass.hasSubClassEq(RC))
BuildMI(MBB, I, DL, get(SP::STDFri)).addFrameIndex(FI).addImm(0)
.addReg(SrcReg, getKillRegState(isKill)).addMemOperand(MMO);
else if (SP::QFPRegsRegClass.hasSubClassEq(RC))
// Use STQFri irrespective of its legality. If STQ is not legal, it will be
// lowered into two STDs in eliminateFrameIndex.
BuildMI(MBB, I, DL, get(SP::STQFri)).addFrameIndex(FI).addImm(0)
.addReg(SrcReg, getKillRegState(isKill)).addMemOperand(MMO);
else
llvm_unreachable("Can't store this register to stack slot");
}
void SparcInstrInfo::
loadRegFromStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
unsigned DestReg, int FI,
const TargetRegisterClass *RC,
const TargetRegisterInfo *TRI) const {
DebugLoc DL;
if (I != MBB.end()) DL = I->getDebugLoc();
MachineFunction *MF = MBB.getParent();
const MachineFrameInfo &MFI = *MF->getFrameInfo();
MachineMemOperand *MMO =
MF->getMachineMemOperand(MachinePointerInfo::getFixedStack(FI),
MachineMemOperand::MOLoad,
MFI.getObjectSize(FI),
MFI.getObjectAlignment(FI));
if (RC == &SP::I64RegsRegClass)
BuildMI(MBB, I, DL, get(SP::LDXri), DestReg).addFrameIndex(FI).addImm(0)
.addMemOperand(MMO);
else if (RC == &SP::IntRegsRegClass)
BuildMI(MBB, I, DL, get(SP::LDri), DestReg).addFrameIndex(FI).addImm(0)
.addMemOperand(MMO);
else if (RC == &SP::FPRegsRegClass)
BuildMI(MBB, I, DL, get(SP::LDFri), DestReg).addFrameIndex(FI).addImm(0)
.addMemOperand(MMO);
else if (SP::DFPRegsRegClass.hasSubClassEq(RC))
BuildMI(MBB, I, DL, get(SP::LDDFri), DestReg).addFrameIndex(FI).addImm(0)
.addMemOperand(MMO);
else if (SP::QFPRegsRegClass.hasSubClassEq(RC))
// Use LDQFri irrespective of its legality. If LDQ is not legal, it will be
// lowered into two LDDs in eliminateFrameIndex.
BuildMI(MBB, I, DL, get(SP::LDQFri), DestReg).addFrameIndex(FI).addImm(0)
.addMemOperand(MMO);
else
llvm_unreachable("Can't load this register from stack slot");
}
unsigned SparcInstrInfo::getGlobalBaseReg(MachineFunction *MF) const
{
SparcMachineFunctionInfo *SparcFI = MF->getInfo<SparcMachineFunctionInfo>();
unsigned GlobalBaseReg = SparcFI->getGlobalBaseReg();
if (GlobalBaseReg != 0)
return GlobalBaseReg;
// Insert the set of GlobalBaseReg into the first MBB of the function
MachineBasicBlock &FirstMBB = MF->front();
MachineBasicBlock::iterator MBBI = FirstMBB.begin();
MachineRegisterInfo &RegInfo = MF->getRegInfo();
const TargetRegisterClass *PtrRC =
Subtarget.is64Bit() ? &SP::I64RegsRegClass : &SP::IntRegsRegClass;
GlobalBaseReg = RegInfo.createVirtualRegister(PtrRC);
DebugLoc dl;
BuildMI(FirstMBB, MBBI, dl, get(SP::GETPCX), GlobalBaseReg);
SparcFI->setGlobalBaseReg(GlobalBaseReg);
return GlobalBaseReg;
}
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