llvm-6502/lib/Target/SystemZ/SystemZRegisterInfo.cpp

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//===- SystemZRegisterInfo.cpp - SystemZ Register 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 SystemZ implementation of the TargetRegisterInfo class.
//
//===----------------------------------------------------------------------===//
#include "SystemZ.h"
#include "SystemZInstrInfo.h"
#include "SystemZMachineFunctionInfo.h"
#include "SystemZRegisterInfo.h"
#include "SystemZSubtarget.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/Target/TargetFrameInfo.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/ADT/BitVector.h"
using namespace llvm;
SystemZRegisterInfo::SystemZRegisterInfo(SystemZTargetMachine &tm,
const SystemZInstrInfo &tii)
: SystemZGenRegisterInfo(SystemZ::ADJCALLSTACKUP, SystemZ::ADJCALLSTACKDOWN),
TM(tm), TII(tii) {
}
const unsigned*
SystemZRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
static const unsigned CalleeSavedRegs[] = {
SystemZ::R6D, SystemZ::R7D, SystemZ::R8D, SystemZ::R9D,
SystemZ::R10D, SystemZ::R11D, SystemZ::R12D, SystemZ::R13D,
SystemZ::R14D, SystemZ::R15D,
SystemZ::F8L, SystemZ::F9L, SystemZ::F10L, SystemZ::F11L,
SystemZ::F12L, SystemZ::F13L, SystemZ::F14L, SystemZ::F15L,
0
};
return CalleeSavedRegs;
}
BitVector SystemZRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
BitVector Reserved(getNumRegs());
if (hasFP(MF))
Reserved.set(SystemZ::R11D);
Reserved.set(SystemZ::R14D);
Reserved.set(SystemZ::R15D);
return Reserved;
}
/// needsFP - Return true if the specified function should have a dedicated
/// frame pointer register. This is true if the function has variable sized
/// allocas or if frame pointer elimination is disabled.
bool SystemZRegisterInfo::hasFP(const MachineFunction &MF) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
return DisableFramePointerElim(MF) || MFI->hasVarSizedObjects();
}
void SystemZRegisterInfo::
eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const {
MBB.erase(I);
}
int SystemZRegisterInfo::getFrameIndexOffset(const MachineFunction &MF,
int FI) const {
const TargetFrameInfo &TFI = *MF.getTarget().getFrameInfo();
const MachineFrameInfo *MFI = MF.getFrameInfo();
const SystemZMachineFunctionInfo *SystemZMFI =
MF.getInfo<SystemZMachineFunctionInfo>();
int Offset = MFI->getObjectOffset(FI) + MFI->getOffsetAdjustment();
uint64_t StackSize = MFI->getStackSize();
// Fixed objects are really located in the "previous" frame.
if (FI < 0)
StackSize -= SystemZMFI->getCalleeSavedFrameSize();
Offset += StackSize - TFI.getOffsetOfLocalArea();
// Skip the register save area if we generated the stack frame.
if (StackSize || MFI->hasCalls())
Offset -= TFI.getOffsetOfLocalArea();
return Offset;
}
void
SystemZRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
int SPAdj, RegScavenger *RS) const {
assert(SPAdj == 0 && "Unxpected");
unsigned i = 0;
MachineInstr &MI = *II;
MachineFunction &MF = *MI.getParent()->getParent();
while (!MI.getOperand(i).isFI()) {
++i;
assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
}
int FrameIndex = MI.getOperand(i).getIndex();
unsigned BasePtr = (hasFP(MF) ? SystemZ::R11D : SystemZ::R15D);
// This must be part of a rri or ri operand memory reference. Replace the
// FrameIndex with base register with BasePtr. Add an offset to the
// displacement field.
MI.getOperand(i).ChangeToRegister(BasePtr, false);
// Offset is a either 12-bit unsigned or 20-bit signed integer.
// FIXME: handle "too long" displacements.
int Offset =
getFrameIndexOffset(MF, FrameIndex) + MI.getOperand(i+1).getImm();
// Check whether displacement is too long to fit into 12 bit zext field.
MI.setDesc(TII.getMemoryInstr(MI.getOpcode(), Offset));
MI.getOperand(i+1).ChangeToImmediate(Offset);
}
void
SystemZRegisterInfo::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
RegScavenger *RS) const {
// Determine whether R15/R14 will ever be clobbered inside the function. And
// if yes - mark it as 'callee' saved.
MachineFrameInfo *FFI = MF.getFrameInfo();
MachineRegisterInfo &MRI = MF.getRegInfo();
// Check whether high FPRs are ever used, if yes - we need to save R15 as
// well.
static const unsigned HighFPRs[] = {
SystemZ::F8L, SystemZ::F9L, SystemZ::F10L, SystemZ::F11L,
SystemZ::F12L, SystemZ::F13L, SystemZ::F14L, SystemZ::F15L,
SystemZ::F8S, SystemZ::F9S, SystemZ::F10S, SystemZ::F11S,
SystemZ::F12S, SystemZ::F13S, SystemZ::F14S, SystemZ::F15S,
};
bool HighFPRsUsed = false;
for (unsigned i = 0, e = array_lengthof(HighFPRs); i != e; ++i)
HighFPRsUsed |= MRI.isPhysRegUsed(HighFPRs[i]);
if (FFI->hasCalls())
/* FIXME: function is varargs */
/* FIXME: function grabs RA */
/* FIXME: function calls eh_return */
MRI.setPhysRegUsed(SystemZ::R14D);
if (HighFPRsUsed ||
FFI->hasCalls() ||
FFI->getObjectIndexEnd() != 0 || // Contains automatic variables
FFI->hasVarSizedObjects() // Function calls dynamic alloca's
/* FIXME: function is varargs */)
MRI.setPhysRegUsed(SystemZ::R15D);
}
/// emitSPUpdate - Emit a series of instructions to increment / decrement the
/// stack pointer by a constant value.
static
void emitSPUpdate(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
int64_t NumBytes, const TargetInstrInfo &TII) {
unsigned Opc; uint64_t Chunk;
bool isSub = NumBytes < 0;
uint64_t Offset = isSub ? -NumBytes : NumBytes;
if (Offset >= (1LL << 15) - 1) {
Opc = SystemZ::ADD64ri32;
Chunk = (1LL << 31) - 1;
} else {
Opc = SystemZ::ADD64ri16;
Chunk = (1LL << 15) - 1;
}
DebugLoc DL = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
while (Offset) {
uint64_t ThisVal = (Offset > Chunk) ? Chunk : Offset;
MachineInstr *MI =
BuildMI(MBB, MBBI, DL, TII.get(Opc), SystemZ::R15D)
.addReg(SystemZ::R15D).addImm(isSub ? -ThisVal : ThisVal);
// The PSW implicit def is dead.
MI->getOperand(3).setIsDead();
Offset -= ThisVal;
}
}
void SystemZRegisterInfo::emitPrologue(MachineFunction &MF) const {
MachineBasicBlock &MBB = MF.front(); // Prolog goes in entry BB
const TargetFrameInfo &TFI = *MF.getTarget().getFrameInfo();
MachineFrameInfo *MFI = MF.getFrameInfo();
SystemZMachineFunctionInfo *SystemZMFI =
MF.getInfo<SystemZMachineFunctionInfo>();
MachineBasicBlock::iterator MBBI = MBB.begin();
DebugLoc DL = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
// Get the number of bytes to allocate from the FrameInfo.
// Note that area for callee-saved stuff is already allocated, thus we need to
// 'undo' the stack movement.
uint64_t StackSize = MFI->getStackSize();
StackSize -= SystemZMFI->getCalleeSavedFrameSize();
uint64_t NumBytes = StackSize - TFI.getOffsetOfLocalArea();
// Skip the callee-saved push instructions.
while (MBBI != MBB.end() &&
(MBBI->getOpcode() == SystemZ::MOV64mr ||
MBBI->getOpcode() == SystemZ::MOV64mrm))
++MBBI;
if (MBBI != MBB.end())
DL = MBBI->getDebugLoc();
// adjust stack pointer: R15 -= numbytes
if (StackSize || MFI->hasCalls()) {
assert(MF.getRegInfo().isPhysRegUsed(SystemZ::R15D) &&
"Invalid stack frame calculation!");
emitSPUpdate(MBB, MBBI, -(int64_t)NumBytes, TII);
}
if (hasFP(MF)) {
// Update R11 with the new base value...
BuildMI(MBB, MBBI, DL, TII.get(SystemZ::MOV64rr), SystemZ::R11D)
.addReg(SystemZ::R15D);
// Mark the FramePtr as live-in in every block except the entry.
for (MachineFunction::iterator I = llvm::next(MF.begin()), E = MF.end();
I != E; ++I)
I->addLiveIn(SystemZ::R11D);
}
}
void SystemZRegisterInfo::emitEpilogue(MachineFunction &MF,
MachineBasicBlock &MBB) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
const TargetFrameInfo &TFI = *MF.getTarget().getFrameInfo();
MachineBasicBlock::iterator MBBI = prior(MBB.end());
SystemZMachineFunctionInfo *SystemZMFI =
MF.getInfo<SystemZMachineFunctionInfo>();
unsigned RetOpcode = MBBI->getOpcode();
switch (RetOpcode) {
case SystemZ::RET: break; // These are ok
default:
assert(0 && "Can only insert epilog into returning blocks");
}
// Get the number of bytes to allocate from the FrameInfo
// Note that area for callee-saved stuff is already allocated, thus we need to
// 'undo' the stack movement.
uint64_t StackSize =
MFI->getStackSize() - SystemZMFI->getCalleeSavedFrameSize();
uint64_t NumBytes = StackSize - TFI.getOffsetOfLocalArea();
// Skip the final terminator instruction.
while (MBBI != MBB.begin()) {
MachineBasicBlock::iterator PI = prior(MBBI);
--MBBI;
if (!PI->getDesc().isTerminator())
break;
}
// During callee-saved restores emission stack frame was not yet finialized
// (and thus - the stack size was unknown). Tune the offset having full stack
// size in hands.
if (StackSize || MFI->hasCalls()) {
assert((MBBI->getOpcode() == SystemZ::MOV64rmm ||
MBBI->getOpcode() == SystemZ::MOV64rm) &&
"Expected to see callee-save register restore code");
assert(MF.getRegInfo().isPhysRegUsed(SystemZ::R15D) &&
"Invalid stack frame calculation!");
unsigned i = 0;
MachineInstr &MI = *MBBI;
while (!MI.getOperand(i).isImm()) {
++i;
assert(i < MI.getNumOperands() && "Unexpected restore code!");
}
uint64_t Offset = NumBytes + MI.getOperand(i).getImm();
// If Offset does not fit into 20-bit signed displacement field we need to
// emit some additional code...
if (Offset > 524287) {
// Fold the displacement into load instruction as much as possible.
NumBytes = Offset - 524287;
Offset = 524287;
emitSPUpdate(MBB, MBBI, NumBytes, TII);
}
MI.getOperand(i).ChangeToImmediate(Offset);
}
}
unsigned SystemZRegisterInfo::getRARegister() const {
assert(0 && "What is the return address register");
return 0;
}
unsigned
SystemZRegisterInfo::getFrameRegister(const MachineFunction &MF) const {
assert(0 && "What is the frame register");
return 0;
}
unsigned SystemZRegisterInfo::getEHExceptionRegister() const {
assert(0 && "What is the exception register");
return 0;
}
unsigned SystemZRegisterInfo::getEHHandlerRegister() const {
assert(0 && "What is the exception handler register");
return 0;
}
int SystemZRegisterInfo::getDwarfRegNum(unsigned RegNum, bool isEH) const {
assert(0 && "What is the dwarf register number");
return -1;
}
#include "SystemZGenRegisterInfo.inc"