#include "ARMAddressingModes.h"
#include "ARMBaseInstrInfo.h"
#include "ARMBaseRegisterInfo.h"
+#include "ARMFrameInfo.h"
#include "ARMInstrInfo.h"
#include "ARMMachineFunctionInfo.h"
#include "ARMSubtarget.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/CommandLine.h"
-namespace llvm {
-cl::opt<bool>
-ReuseFrameIndexVals("arm-reuse-frame-index-vals", cl::Hidden, cl::init(true),
- cl::desc("Reuse repeated frame index values"));
-}
-
using namespace llvm;
-unsigned ARMBaseRegisterInfo::getRegisterNumbering(unsigned RegEnum,
- bool *isSPVFP) {
- if (isSPVFP)
- *isSPVFP = false;
-
- using namespace ARM;
- switch (RegEnum) {
- default:
- llvm_unreachable("Unknown ARM register!");
- case R0: case D0: case Q0: return 0;
- case R1: case D1: case Q1: return 1;
- case R2: case D2: case Q2: return 2;
- case R3: case D3: case Q3: return 3;
- case R4: case D4: case Q4: return 4;
- case R5: case D5: case Q5: return 5;
- case R6: case D6: case Q6: return 6;
- case R7: case D7: case Q7: return 7;
- case R8: case D8: case Q8: return 8;
- case R9: case D9: case Q9: return 9;
- case R10: case D10: case Q10: return 10;
- case R11: case D11: case Q11: return 11;
- case R12: case D12: case Q12: return 12;
- case SP: case D13: case Q13: return 13;
- case LR: case D14: case Q14: return 14;
- case PC: case D15: case Q15: return 15;
-
- case D16: return 16;
- case D17: return 17;
- case D18: return 18;
- case D19: return 19;
- case D20: return 20;
- case D21: return 21;
- case D22: return 22;
- case D23: return 23;
- case D24: return 24;
- case D25: return 25;
- case D26: return 26;
- case D27: return 27;
- case D28: return 28;
- case D29: return 29;
- case D30: return 30;
- case D31: return 31;
-
- case S0: case S1: case S2: case S3:
- case S4: case S5: case S6: case S7:
- case S8: case S9: case S10: case S11:
- case S12: case S13: case S14: case S15:
- case S16: case S17: case S18: case S19:
- case S20: case S21: case S22: case S23:
- case S24: case S25: case S26: case S27:
- case S28: case S29: case S30: case S31: {
- if (isSPVFP)
- *isSPVFP = true;
- switch (RegEnum) {
- default: return 0; // Avoid compile time warning.
- case S0: return 0;
- case S1: return 1;
- case S2: return 2;
- case S3: return 3;
- case S4: return 4;
- case S5: return 5;
- case S6: return 6;
- case S7: return 7;
- case S8: return 8;
- case S9: return 9;
- case S10: return 10;
- case S11: return 11;
- case S12: return 12;
- case S13: return 13;
- case S14: return 14;
- case S15: return 15;
- case S16: return 16;
- case S17: return 17;
- case S18: return 18;
- case S19: return 19;
- case S20: return 20;
- case S21: return 21;
- case S22: return 22;
- case S23: return 23;
- case S24: return 24;
- case S25: return 25;
- case S26: return 26;
- case S27: return 27;
- case S28: return 28;
- case S29: return 29;
- case S30: return 30;
- case S31: return 31;
- }
- }
- }
-}
+static cl::opt<bool>
+ForceAllBaseRegAlloc("arm-force-base-reg-alloc", cl::Hidden, cl::init(false),
+ cl::desc("Force use of virtual base registers for stack load/store"));
+static cl::opt<bool>
+EnableLocalStackAlloc("enable-local-stack-alloc", cl::init(true), cl::Hidden,
+ cl::desc("Enable pre-regalloc stack frame index allocation"));
+static cl::opt<bool>
+EnableBasePointer("arm-use-base-pointer", cl::Hidden, cl::init(true),
+ cl::desc("Enable use of a base pointer for complex stack frames"));
ARMBaseRegisterInfo::ARMBaseRegisterInfo(const ARMBaseInstrInfo &tii,
const ARMSubtarget &sti)
: ARMGenRegisterInfo(ARM::ADJCALLSTACKDOWN, ARM::ADJCALLSTACKUP),
TII(tii), STI(sti),
- FramePtr((STI.isTargetDarwin() || STI.isThumb()) ? ARM::R7 : ARM::R11) {
+ FramePtr((STI.isTargetDarwin() || STI.isThumb()) ? ARM::R7 : ARM::R11),
+ BasePtr(ARM::R6) {
}
const unsigned*
BitVector ARMBaseRegisterInfo::
getReservedRegs(const MachineFunction &MF) const {
+ const TargetFrameInfo *TFI = MF.getTarget().getFrameInfo();
+
// FIXME: avoid re-calculating this everytime.
BitVector Reserved(getNumRegs());
Reserved.set(ARM::SP);
Reserved.set(ARM::PC);
Reserved.set(ARM::FPSCR);
- if (hasFP(MF))
+ if (TFI->hasFP(MF))
Reserved.set(FramePtr);
+ if (hasBasePointer(MF))
+ Reserved.set(BasePtr);
// Some targets reserve R9.
if (STI.isR9Reserved())
Reserved.set(ARM::R9);
bool ARMBaseRegisterInfo::isReservedReg(const MachineFunction &MF,
unsigned Reg) const {
+ const TargetFrameInfo *TFI = MF.getTarget().getFrameInfo();
+
switch (Reg) {
default: break;
case ARM::SP:
case ARM::PC:
return true;
+ case ARM::R6:
+ if (hasBasePointer(MF))
+ return true;
+ break;
case ARM::R7:
case ARM::R11:
- if (FramePtr == Reg && hasFP(MF))
+ if (FramePtr == Reg && TFI->hasFP(MF))
return true;
break;
case ARM::R9:
ARMBaseRegisterInfo::getAllocationOrder(const TargetRegisterClass *RC,
unsigned HintType, unsigned HintReg,
const MachineFunction &MF) const {
+ const TargetFrameInfo *TFI = MF.getTarget().getFrameInfo();
// Alternative register allocation orders when favoring even / odd registers
// of register pairs.
return std::make_pair(RC->allocation_order_begin(MF),
RC->allocation_order_end(MF));
- if (!hasFP(MF)) {
+ if (!TFI->hasFP(MF)) {
if (!STI.isR9Reserved())
return std::make_pair(GPREven1,
GPREven1 + (sizeof(GPREven1)/sizeof(unsigned)));
return std::make_pair(RC->allocation_order_begin(MF),
RC->allocation_order_end(MF));
- if (!hasFP(MF)) {
+ if (!TFI->hasFP(MF)) {
if (!STI.isR9Reserved())
return std::make_pair(GPROdd1,
GPROdd1 + (sizeof(GPROdd1)/sizeof(unsigned)));
}
}
-/// hasFP - 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 ARMBaseRegisterInfo::hasFP(const MachineFunction &MF) const {
- // Mac OS X requires FP not to be clobbered for backtracing purpose.
- if (STI.isTargetDarwin())
+bool ARMBaseRegisterInfo::hasBasePointer(const MachineFunction &MF) const {
+ const MachineFrameInfo *MFI = MF.getFrameInfo();
+ const ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
+
+ if (!EnableBasePointer)
+ return false;
+
+ if (needsStackRealignment(MF) && MFI->hasVarSizedObjects())
return true;
- const MachineFrameInfo *MFI = MF.getFrameInfo();
- // Always eliminate non-leaf frame pointers.
- return ((DisableFramePointerElim(MF) && MFI->hasCalls()) ||
- needsStackRealignment(MF) ||
- MFI->hasVarSizedObjects() ||
- MFI->isFrameAddressTaken());
+ // Thumb has trouble with negative offsets from the FP. Thumb2 has a limited
+ // negative range for ldr/str (255), and thumb1 is positive offsets only.
+ // It's going to be better to use the SP or Base Pointer instead. When there
+ // are variable sized objects, we can't reference off of the SP, so we
+ // reserve a Base Pointer.
+ if (AFI->isThumbFunction() && MFI->hasVarSizedObjects()) {
+ // Conservatively estimate whether the negative offset from the frame
+ // pointer will be sufficient to reach. If a function has a smallish
+ // frame, it's less likely to have lots of spills and callee saved
+ // space, so it's all more likely to be within range of the frame pointer.
+ // If it's wrong, the scavenger will still enable access to work, it just
+ // won't be optimal.
+ if (AFI->isThumb2Function() && MFI->getLocalFrameSize() < 128)
+ return false;
+ return true;
+ }
+
+ return false;
}
bool ARMBaseRegisterInfo::canRealignStack(const MachineFunction &MF) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
const ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
- return (RealignStack &&
- !AFI->isThumb1OnlyFunction() &&
- !MFI->hasVarSizedObjects());
+ // We can't realign the stack if:
+ // 1. Dynamic stack realignment is explicitly disabled,
+ // 2. This is a Thumb1 function (it's not useful, so we don't bother), or
+ // 3. There are VLAs in the function and the base pointer is disabled.
+ return (RealignStack && !AFI->isThumb1OnlyFunction() &&
+ (!MFI->hasVarSizedObjects() || EnableBasePointer));
}
bool ARMBaseRegisterInfo::
needsStackRealignment(const MachineFunction &MF) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
const Function *F = MF.getFunction();
- const ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
unsigned StackAlign = MF.getTarget().getFrameInfo()->getStackAlignment();
- bool requiresRealignment = ((MFI->getMaxAlignment() > StackAlign) ||
+ bool requiresRealignment = ((MFI->getLocalFrameMaxAlign() > StackAlign) ||
F->hasFnAttr(Attribute::StackAlignment));
-
- // FIXME: Currently we don't support stack realignment for functions with
- // variable-sized allocas.
- // FIXME: It's more complicated than this...
- if (0 && requiresRealignment && MFI->hasVarSizedObjects())
- report_fatal_error(
- "Stack realignment in presense of dynamic allocas is not supported");
-
- // FIXME: This probably isn't the right place for this.
- if (0 && requiresRealignment && AFI->isThumb1OnlyFunction())
- report_fatal_error(
- "Stack realignment in thumb1 functions is not supported");
-
+
return requiresRealignment && canRealignStack(MF);
}
|| needsStackRealignment(MF);
}
-/// estimateStackSize - Estimate and return the size of the frame.
-static unsigned estimateStackSize(MachineFunction &MF) {
- const MachineFrameInfo *FFI = MF.getFrameInfo();
- int Offset = 0;
- for (int i = FFI->getObjectIndexBegin(); i != 0; ++i) {
- int FixedOff = -FFI->getObjectOffset(i);
- if (FixedOff > Offset) Offset = FixedOff;
- }
- for (unsigned i = 0, e = FFI->getObjectIndexEnd(); i != e; ++i) {
- if (FFI->isDeadObjectIndex(i))
- continue;
- Offset += FFI->getObjectSize(i);
- unsigned Align = FFI->getObjectAlignment(i);
- // Adjust to alignment boundary
- Offset = (Offset+Align-1)/Align*Align;
- }
- return (unsigned)Offset;
-}
-
-/// estimateRSStackSizeLimit - Look at each instruction that references stack
-/// frames and return the stack size limit beyond which some of these
-/// instructions will require a scratch register during their expansion later.
-unsigned
-ARMBaseRegisterInfo::estimateRSStackSizeLimit(MachineFunction &MF) const {
- const ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
- unsigned Limit = (1 << 12) - 1;
- for (MachineFunction::iterator BB = MF.begin(),E = MF.end(); BB != E; ++BB) {
- for (MachineBasicBlock::iterator I = BB->begin(), E = BB->end();
- I != E; ++I) {
- for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
- if (!I->getOperand(i).isFI()) continue;
-
- // When using ADDri to get the address of a stack object, 255 is the
- // largest offset guaranteed to fit in the immediate offset.
- if (I->getOpcode() == ARM::ADDri) {
- Limit = std::min(Limit, (1U << 8) - 1);
- break;
- }
-
- // Otherwise check the addressing mode.
- switch (I->getDesc().TSFlags & ARMII::AddrModeMask) {
- case ARMII::AddrMode3:
- case ARMII::AddrModeT2_i8:
- Limit = std::min(Limit, (1U << 8) - 1);
- break;
- case ARMII::AddrMode5:
- case ARMII::AddrModeT2_i8s4:
- Limit = std::min(Limit, ((1U << 8) - 1) * 4);
- break;
- case ARMII::AddrModeT2_i12:
- // i12 supports only positive offset so these will be converted to
- // i8 opcodes. See llvm::rewriteT2FrameIndex.
- if (hasFP(MF) && AFI->hasStackFrame())
- Limit = std::min(Limit, (1U << 8) - 1);
- break;
- case ARMII::AddrMode6:
- // Addressing mode 6 (load/store) instructions can't encode an
- // immediate offset for stack references.
- return 0;
- default:
- break;
- }
- break; // At most one FI per instruction
- }
- }
- }
-
- return Limit;
-}
-
-static unsigned GetFunctionSizeInBytes(const MachineFunction &MF,
- const ARMBaseInstrInfo &TII) {
- unsigned FnSize = 0;
- for (MachineFunction::const_iterator MBBI = MF.begin(), E = MF.end();
- MBBI != E; ++MBBI) {
- const MachineBasicBlock &MBB = *MBBI;
- for (MachineBasicBlock::const_iterator I = MBB.begin(),E = MBB.end();
- I != E; ++I)
- FnSize += TII.GetInstSizeInBytes(I);
- }
- return FnSize;
-}
-
-void
-ARMBaseRegisterInfo::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
- RegScavenger *RS) const {
- // This tells PEI to spill the FP as if it is any other callee-save register
- // to take advantage the eliminateFrameIndex machinery. This also ensures it
- // is spilled in the order specified by getCalleeSavedRegs() to make it easier
- // to combine multiple loads / stores.
- bool CanEliminateFrame = true;
- bool CS1Spilled = false;
- bool LRSpilled = false;
- unsigned NumGPRSpills = 0;
- SmallVector<unsigned, 4> UnspilledCS1GPRs;
- SmallVector<unsigned, 4> UnspilledCS2GPRs;
- ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
- MachineFrameInfo *MFI = MF.getFrameInfo();
-
- // Spill R4 if Thumb2 function requires stack realignment - it will be used as
- // scratch register.
- // FIXME: It will be better just to find spare register here.
- if (needsStackRealignment(MF) &&
- AFI->isThumb2Function())
- MF.getRegInfo().setPhysRegUsed(ARM::R4);
-
- // Spill LR if Thumb1 function uses variable length argument lists.
- if (AFI->isThumb1OnlyFunction() && AFI->getVarArgsRegSaveSize() > 0)
- MF.getRegInfo().setPhysRegUsed(ARM::LR);
-
- // Don't spill FP if the frame can be eliminated. This is determined
- // by scanning the callee-save registers to see if any is used.
- const unsigned *CSRegs = getCalleeSavedRegs();
- for (unsigned i = 0; CSRegs[i]; ++i) {
- unsigned Reg = CSRegs[i];
- bool Spilled = false;
- if (MF.getRegInfo().isPhysRegUsed(Reg)) {
- AFI->setCSRegisterIsSpilled(Reg);
- Spilled = true;
- CanEliminateFrame = false;
- } else {
- // Check alias registers too.
- for (const unsigned *Aliases = getAliasSet(Reg); *Aliases; ++Aliases) {
- if (MF.getRegInfo().isPhysRegUsed(*Aliases)) {
- Spilled = true;
- CanEliminateFrame = false;
- }
- }
- }
-
- if (!ARM::GPRRegisterClass->contains(Reg))
- continue;
-
- if (Spilled) {
- NumGPRSpills++;
-
- if (!STI.isTargetDarwin()) {
- if (Reg == ARM::LR)
- LRSpilled = true;
- CS1Spilled = true;
- continue;
- }
-
- // Keep track if LR and any of R4, R5, R6, and R7 is spilled.
- switch (Reg) {
- case ARM::LR:
- LRSpilled = true;
- // Fallthrough
- case ARM::R4:
- case ARM::R5:
- case ARM::R6:
- case ARM::R7:
- CS1Spilled = true;
- break;
- default:
- break;
- }
- } else {
- if (!STI.isTargetDarwin()) {
- UnspilledCS1GPRs.push_back(Reg);
- continue;
- }
-
- switch (Reg) {
- case ARM::R4:
- case ARM::R5:
- case ARM::R6:
- case ARM::R7:
- case ARM::LR:
- UnspilledCS1GPRs.push_back(Reg);
- break;
- default:
- UnspilledCS2GPRs.push_back(Reg);
- break;
- }
- }
- }
-
- bool ForceLRSpill = false;
- if (!LRSpilled && AFI->isThumb1OnlyFunction()) {
- unsigned FnSize = GetFunctionSizeInBytes(MF, TII);
- // Force LR to be spilled if the Thumb function size is > 2048. This enables
- // use of BL to implement far jump. If it turns out that it's not needed
- // then the branch fix up path will undo it.
- if (FnSize >= (1 << 11)) {
- CanEliminateFrame = false;
- ForceLRSpill = true;
- }
- }
-
- // If any of the stack slot references may be out of range of an immediate
- // offset, make sure a register (or a spill slot) is available for the
- // register scavenger. Note that if we're indexing off the frame pointer, the
- // effective stack size is 4 bytes larger since the FP points to the stack
- // slot of the previous FP. Also, if we have variable sized objects in the
- // function, stack slot references will often be negative, and some of
- // our instructions are positive-offset only, so conservatively consider
- // that case to want a spill slot (or register) as well. Similarly, if
- // the function adjusts the stack pointer during execution and the
- // adjustments aren't already part of our stack size estimate, our offset
- // calculations may be off, so be conservative.
- // FIXME: We could add logic to be more precise about negative offsets
- // and which instructions will need a scratch register for them. Is it
- // worth the effort and added fragility?
- bool BigStack =
- (RS &&
- (estimateStackSize(MF) + ((hasFP(MF) && AFI->hasStackFrame()) ? 4:0) >=
- estimateRSStackSizeLimit(MF)))
- || MFI->hasVarSizedObjects()
- || (MFI->adjustsStack() && !canSimplifyCallFramePseudos(MF));
-
- bool ExtraCSSpill = false;
- if (BigStack || !CanEliminateFrame || cannotEliminateFrame(MF)) {
- AFI->setHasStackFrame(true);
-
- // If LR is not spilled, but at least one of R4, R5, R6, and R7 is spilled.
- // Spill LR as well so we can fold BX_RET to the registers restore (LDM).
- if (!LRSpilled && CS1Spilled) {
- MF.getRegInfo().setPhysRegUsed(ARM::LR);
- AFI->setCSRegisterIsSpilled(ARM::LR);
- NumGPRSpills++;
- UnspilledCS1GPRs.erase(std::find(UnspilledCS1GPRs.begin(),
- UnspilledCS1GPRs.end(), (unsigned)ARM::LR));
- ForceLRSpill = false;
- ExtraCSSpill = true;
- }
-
- if (hasFP(MF)) {
- MF.getRegInfo().setPhysRegUsed(FramePtr);
- NumGPRSpills++;
- }
-
- // If stack and double are 8-byte aligned and we are spilling an odd number
- // of GPRs. Spill one extra callee save GPR so we won't have to pad between
- // the integer and double callee save areas.
- unsigned TargetAlign = MF.getTarget().getFrameInfo()->getStackAlignment();
- if (TargetAlign == 8 && (NumGPRSpills & 1)) {
- if (CS1Spilled && !UnspilledCS1GPRs.empty()) {
- for (unsigned i = 0, e = UnspilledCS1GPRs.size(); i != e; ++i) {
- unsigned Reg = UnspilledCS1GPRs[i];
- // Don't spill high register if the function is thumb1
- if (!AFI->isThumb1OnlyFunction() ||
- isARMLowRegister(Reg) || Reg == ARM::LR) {
- MF.getRegInfo().setPhysRegUsed(Reg);
- AFI->setCSRegisterIsSpilled(Reg);
- if (!isReservedReg(MF, Reg))
- ExtraCSSpill = true;
- break;
- }
- }
- } else if (!UnspilledCS2GPRs.empty() &&
- !AFI->isThumb1OnlyFunction()) {
- unsigned Reg = UnspilledCS2GPRs.front();
- MF.getRegInfo().setPhysRegUsed(Reg);
- AFI->setCSRegisterIsSpilled(Reg);
- if (!isReservedReg(MF, Reg))
- ExtraCSSpill = true;
- }
- }
-
- // Estimate if we might need to scavenge a register at some point in order
- // to materialize a stack offset. If so, either spill one additional
- // callee-saved register or reserve a special spill slot to facilitate
- // register scavenging. Thumb1 needs a spill slot for stack pointer
- // adjustments also, even when the frame itself is small.
- if (BigStack && !ExtraCSSpill) {
- // If any non-reserved CS register isn't spilled, just spill one or two
- // extra. That should take care of it!
- unsigned NumExtras = TargetAlign / 4;
- SmallVector<unsigned, 2> Extras;
- while (NumExtras && !UnspilledCS1GPRs.empty()) {
- unsigned Reg = UnspilledCS1GPRs.back();
- UnspilledCS1GPRs.pop_back();
- if (!isReservedReg(MF, Reg) &&
- (!AFI->isThumb1OnlyFunction() || isARMLowRegister(Reg) ||
- Reg == ARM::LR)) {
- Extras.push_back(Reg);
- NumExtras--;
- }
- }
- // For non-Thumb1 functions, also check for hi-reg CS registers
- if (!AFI->isThumb1OnlyFunction()) {
- while (NumExtras && !UnspilledCS2GPRs.empty()) {
- unsigned Reg = UnspilledCS2GPRs.back();
- UnspilledCS2GPRs.pop_back();
- if (!isReservedReg(MF, Reg)) {
- Extras.push_back(Reg);
- NumExtras--;
- }
- }
- }
- if (Extras.size() && NumExtras == 0) {
- for (unsigned i = 0, e = Extras.size(); i != e; ++i) {
- MF.getRegInfo().setPhysRegUsed(Extras[i]);
- AFI->setCSRegisterIsSpilled(Extras[i]);
- }
- } else if (!AFI->isThumb1OnlyFunction()) {
- // note: Thumb1 functions spill to R12, not the stack. Reserve a slot
- // closest to SP or frame pointer.
- const TargetRegisterClass *RC = ARM::GPRRegisterClass;
- RS->setScavengingFrameIndex(MFI->CreateStackObject(RC->getSize(),
- RC->getAlignment(),
- false));
- }
- }
- }
-
- if (ForceLRSpill) {
- MF.getRegInfo().setPhysRegUsed(ARM::LR);
- AFI->setCSRegisterIsSpilled(ARM::LR);
- AFI->setLRIsSpilledForFarJump(true);
- }
-}
-
unsigned ARMBaseRegisterInfo::getRARegister() const {
return ARM::LR;
}
-unsigned
+unsigned
ARMBaseRegisterInfo::getFrameRegister(const MachineFunction &MF) const {
- if (hasFP(MF))
+ const TargetFrameInfo *TFI = MF.getTarget().getFrameInfo();
+
+ if (TFI->hasFP(MF))
return FramePtr;
return ARM::SP;
}
-// Provide a base+offset reference to an FI slot for debug info. It's the
-// same as what we use for resolving the code-gen references for now.
-// FIXME: This can go wrong when references are SP-relative and simple call
-// frames aren't used.
-int
-ARMBaseRegisterInfo::getFrameIndexReference(const MachineFunction &MF, int FI,
- unsigned &FrameReg) const {
- return ResolveFrameIndexReference(MF, FI, FrameReg, 0);
-}
-
-int
-ARMBaseRegisterInfo::ResolveFrameIndexReference(const MachineFunction &MF,
- int FI,
- unsigned &FrameReg,
- int SPAdj) const {
- const MachineFrameInfo *MFI = MF.getFrameInfo();
- const ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
- int Offset = MFI->getObjectOffset(FI) + MFI->getStackSize();
- int FPOffset = Offset - AFI->getFramePtrSpillOffset();
- bool isFixed = MFI->isFixedObjectIndex(FI);
-
- FrameReg = ARM::SP;
- Offset += SPAdj;
- if (AFI->isGPRCalleeSavedArea1Frame(FI))
- return Offset - AFI->getGPRCalleeSavedArea1Offset();
- else if (AFI->isGPRCalleeSavedArea2Frame(FI))
- return Offset - AFI->getGPRCalleeSavedArea2Offset();
- else if (AFI->isDPRCalleeSavedAreaFrame(FI))
- return Offset - AFI->getDPRCalleeSavedAreaOffset();
-
- // When dynamically realigning the stack, use the frame pointer for
- // parameters, and the stack pointer for locals.
- if (needsStackRealignment(MF)) {
- assert (hasFP(MF) && "dynamic stack realignment without a FP!");
- if (isFixed) {
- FrameReg = getFrameRegister(MF);
- Offset = FPOffset;
- }
- return Offset;
- }
-
- // If there is a frame pointer, use it when we can.
- if (hasFP(MF) && AFI->hasStackFrame()) {
- // Use frame pointer to reference fixed objects. Use it for locals if
- // there are VLAs (and thus the SP isn't reliable as a base).
- if (isFixed || MFI->hasVarSizedObjects()) {
- FrameReg = getFrameRegister(MF);
- Offset = FPOffset;
- } else if (AFI->isThumb2Function()) {
- // In Thumb2 mode, the negative offset is very limited. Try to avoid
- // out of range references.
- if (FPOffset >= -255 && FPOffset < 0) {
- FrameReg = getFrameRegister(MF);
- Offset = FPOffset;
- }
- } else if (Offset > (FPOffset < 0 ? -FPOffset : FPOffset)) {
- // Otherwise, use SP or FP, whichever is closer to the stack slot.
- FrameReg = getFrameRegister(MF);
- Offset = FPOffset;
- }
- }
- return Offset;
-}
-
-int
-ARMBaseRegisterInfo::getFrameIndexOffset(const MachineFunction &MF,
- int FI) const {
- unsigned FrameReg;
- return getFrameIndexReference(MF, FI, FrameReg);
-}
-
unsigned ARMBaseRegisterInfo::getEHExceptionRegister() const {
llvm_unreachable("What is the exception register");
return 0;
case ARM::R5:
return ARM::R4;
case ARM::R7:
- return isReservedReg(MF, ARM::R7) ? 0 : ARM::R6;
+ return (isReservedReg(MF, ARM::R7) || isReservedReg(MF, ARM::R6))
+ ? 0 : ARM::R6;
case ARM::R9:
return isReservedReg(MF, ARM::R9) ? 0 :ARM::R8;
case ARM::R11:
case ARM::R4:
return ARM::R5;
case ARM::R6:
- return isReservedReg(MF, ARM::R7) ? 0 : ARM::R7;
+ return (isReservedReg(MF, ARM::R7) || isReservedReg(MF, ARM::R6))
+ ? 0 : ARM::R7;
case ARM::R8:
return isReservedReg(MF, ARM::R9) ? 0 :ARM::R9;
case ARM::R10:
BuildMI(MBB, MBBI, dl, TII.get(ARM::LDRcp))
.addReg(DestReg, getDefRegState(true), SubIdx)
.addConstantPoolIndex(Idx)
- .addReg(0).addImm(0).addImm(Pred).addReg(PredReg);
+ .addImm(0).addImm(Pred).addReg(PredReg);
}
bool ARMBaseRegisterInfo::
return true;
}
-// hasReservedCallFrame - Under normal circumstances, when a frame pointer is
-// not required, we reserve argument space for call sites in the function
-// immediately on entry to the current function. This eliminates the need for
-// add/sub sp brackets around call sites. Returns true if the call frame is
-// included as part of the stack frame.
bool ARMBaseRegisterInfo::
-hasReservedCallFrame(const MachineFunction &MF) const {
- const MachineFrameInfo *FFI = MF.getFrameInfo();
- unsigned CFSize = FFI->getMaxCallFrameSize();
- // It's not always a good idea to include the call frame as part of the
- // stack frame. ARM (especially Thumb) has small immediate offset to
- // address the stack frame. So a large call frame can cause poor codegen
- // and may even makes it impossible to scavenge a register.
- if (CFSize >= ((1 << 12) - 1) / 2) // Half of imm12
- return false;
-
- return !MF.getFrameInfo()->hasVarSizedObjects();
-}
-
-// canSimplifyCallFramePseudos - If there is a reserved call frame, the
-// call frame pseudos can be simplified. Unlike most targets, having a FP
-// is not sufficient here since we still may reference some objects via SP
-// even when FP is available in Thumb2 mode.
-bool ARMBaseRegisterInfo::
-canSimplifyCallFramePseudos(const MachineFunction &MF) const {
- return hasReservedCallFrame(MF) || MF.getFrameInfo()->hasVarSizedObjects();
+requiresVirtualBaseRegisters(const MachineFunction &MF) const {
+ return EnableLocalStackAlloc;
}
static void
void ARMBaseRegisterInfo::
eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) const {
- if (!hasReservedCallFrame(MF)) {
+ const TargetFrameInfo *TFI = MF.getTarget().getFrameInfo();
+ if (!TFI->hasReservedCallFrame(MF)) {
// If we have alloca, convert as follows:
// ADJCALLSTACKDOWN -> sub, sp, sp, amount
// ADJCALLSTACKUP -> add, sp, sp, amount
MBB.erase(I);
}
+int64_t ARMBaseRegisterInfo::
+getFrameIndexInstrOffset(const MachineInstr *MI, int Idx) const {
+ const TargetInstrDesc &Desc = MI->getDesc();
+ unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
+ int64_t InstrOffs = 0;;
+ int Scale = 1;
+ unsigned ImmIdx = 0;
+ switch (AddrMode) {
+ case ARMII::AddrModeT2_i8:
+ case ARMII::AddrModeT2_i12:
+ case ARMII::AddrMode_i12:
+ InstrOffs = MI->getOperand(Idx+1).getImm();
+ Scale = 1;
+ break;
+ case ARMII::AddrMode5: {
+ // VFP address mode.
+ const MachineOperand &OffOp = MI->getOperand(Idx+1);
+ InstrOffs = ARM_AM::getAM5Offset(OffOp.getImm());
+ if (ARM_AM::getAM5Op(OffOp.getImm()) == ARM_AM::sub)
+ InstrOffs = -InstrOffs;
+ Scale = 4;
+ break;
+ }
+ case ARMII::AddrMode2: {
+ ImmIdx = Idx+2;
+ InstrOffs = ARM_AM::getAM2Offset(MI->getOperand(ImmIdx).getImm());
+ if (ARM_AM::getAM2Op(MI->getOperand(ImmIdx).getImm()) == ARM_AM::sub)
+ InstrOffs = -InstrOffs;
+ break;
+ }
+ case ARMII::AddrMode3: {
+ ImmIdx = Idx+2;
+ InstrOffs = ARM_AM::getAM3Offset(MI->getOperand(ImmIdx).getImm());
+ if (ARM_AM::getAM3Op(MI->getOperand(ImmIdx).getImm()) == ARM_AM::sub)
+ InstrOffs = -InstrOffs;
+ break;
+ }
+ case ARMII::AddrModeT1_s: {
+ ImmIdx = Idx+1;
+ InstrOffs = MI->getOperand(ImmIdx).getImm();
+ Scale = 4;
+ break;
+ }
+ default:
+ llvm_unreachable("Unsupported addressing mode!");
+ break;
+ }
+
+ return InstrOffs * Scale;
+}
+
/// needsFrameBaseReg - Returns true if the instruction's frame index
/// reference would be better served by a base register other than FP
/// or SP. Used by LocalStackFrameAllocation to determine which frame index
/// references it should create new base registers for.
bool ARMBaseRegisterInfo::
-needsFrameBaseReg(MachineInstr *MI, unsigned operand) const {
- assert (MI->getOperand(operand).isFI() &&
- "needsFrameBaseReg() called on non Frame Index operand!");
+needsFrameBaseReg(MachineInstr *MI, int64_t Offset) const {
+ for (unsigned i = 0; !MI->getOperand(i).isFI(); ++i) {
+ assert(i < MI->getNumOperands() &&"Instr doesn't have FrameIndex operand!");
+ }
// It's the load/store FI references that cause issues, as it can be difficult
// to materialize the offset if it won't fit in the literal field. Estimate
// we don't know everything for certain yet) whether this offset is likely
// to be out of range of the immediate. Return true if so.
- // FIXME: For testing, return true for all loads/stores and false for
- // everything else. We want to create lots of base regs to shake out bugs.
- //
- // FIXME: This is Thumb2/ARM only for now to keep it simpler.
- ARMFunctionInfo *AFI =
- MI->getParent()->getParent()->getInfo<ARMFunctionInfo>();
- if (AFI->isThumb1OnlyFunction())
- return false;
-
+ // We only generate virtual base registers for loads and stores, so
+ // return false for everything else.
unsigned Opc = MI->getOpcode();
-
switch (Opc) {
- case ARM::LDR: case ARM::LDRH: case ARM::LDRB:
- case ARM::STR: case ARM::STRH: case ARM::STRB:
+ case ARM::LDRi12: case ARM::LDRH: case ARM::LDRBi12:
+ case ARM::STRi12: case ARM::STRH: case ARM::STRBi12:
case ARM::t2LDRi12: case ARM::t2LDRi8:
case ARM::t2STRi12: case ARM::t2STRi8:
case ARM::VLDRS: case ARM::VLDRD:
case ARM::VSTRS: case ARM::VSTRD:
- return true;
+ case ARM::tSTRspi: case ARM::tLDRspi:
+ if (ForceAllBaseRegAlloc)
+ return true;
+ break;
default:
return false;
}
+
+ // Without a virtual base register, if the function has variable sized
+ // objects, all fixed-size local references will be via the frame pointer,
+ // Approximate the offset and see if it's legal for the instruction.
+ // Note that the incoming offset is based on the SP value at function entry,
+ // so it'll be negative.
+ MachineFunction &MF = *MI->getParent()->getParent();
+ const TargetFrameInfo *TFI = MF.getTarget().getFrameInfo();
+ MachineFrameInfo *MFI = MF.getFrameInfo();
+ ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
+
+ // Estimate an offset from the frame pointer.
+ // Conservatively assume all callee-saved registers get pushed. R4-R6
+ // will be earlier than the FP, so we ignore those.
+ // R7, LR
+ int64_t FPOffset = Offset - 8;
+ // ARM and Thumb2 functions also need to consider R8-R11 and D8-D15
+ if (!AFI->isThumbFunction() || !AFI->isThumb1OnlyFunction())
+ FPOffset -= 80;
+ // Estimate an offset from the stack pointer.
+ // The incoming offset is relating to the SP at the start of the function,
+ // but when we access the local it'll be relative to the SP after local
+ // allocation, so adjust our SP-relative offset by that allocation size.
+ Offset = -Offset;
+ Offset += MFI->getLocalFrameSize();
+ // Assume that we'll have at least some spill slots allocated.
+ // FIXME: This is a total SWAG number. We should run some statistics
+ // and pick a real one.
+ Offset += 128; // 128 bytes of spill slots
+
+ // If there is a frame pointer, try using it.
+ // The FP is only available if there is no dynamic realignment. We
+ // don't know for sure yet whether we'll need that, so we guess based
+ // on whether there are any local variables that would trigger it.
+ unsigned StackAlign = MF.getTarget().getFrameInfo()->getStackAlignment();
+ if (TFI->hasFP(MF) &&
+ !((MFI->getLocalFrameMaxAlign() > StackAlign) && canRealignStack(MF))) {
+ if (isFrameOffsetLegal(MI, FPOffset))
+ return false;
+ }
+ // If we can reference via the stack pointer, try that.
+ // FIXME: This (and the code that resolves the references) can be improved
+ // to only disallow SP relative references in the live range of
+ // the VLA(s). In practice, it's unclear how much difference that
+ // would make, but it may be worth doing.
+ if (!MFI->hasVarSizedObjects() && isFrameOffsetLegal(MI, Offset))
+ return false;
+
+ // The offset likely isn't legal, we want to allocate a virtual base register.
+ return true;
}
/// materializeFrameBaseRegister - Insert defining instruction(s) for
/// BaseReg to be a pointer to FrameIdx before insertion point I.
void ARMBaseRegisterInfo::
-materializeFrameBaseRegister(MachineBasicBlock::iterator I,
- unsigned BaseReg, int FrameIdx) const {
+materializeFrameBaseRegister(MachineBasicBlock::iterator I, unsigned BaseReg,
+ int FrameIdx, int64_t Offset) const {
ARMFunctionInfo *AFI =
I->getParent()->getParent()->getInfo<ARMFunctionInfo>();
- unsigned ADDriOpc = !AFI->isThumbFunction() ? ARM::ADDri : ARM::t2ADDri;
- assert(!AFI->isThumb1OnlyFunction() &&
- "This materializeFrameBaseRegister does not support Thumb1!");
+ unsigned ADDriOpc = !AFI->isThumbFunction() ? ARM::ADDri :
+ (AFI->isThumb1OnlyFunction() ? ARM::tADDrSPi : ARM::t2ADDri);
MachineInstrBuilder MIB =
BuildMI(*I->getParent(), I, I->getDebugLoc(), TII.get(ADDriOpc), BaseReg)
- .addFrameIndex(FrameIdx).addImm(0);
- AddDefaultCC(AddDefaultPred(MIB));
+ .addFrameIndex(FrameIdx).addImm(Offset);
+ if (!AFI->isThumb1OnlyFunction())
+ AddDefaultCC(AddDefaultPred(MIB));
}
void
assert (Done && "Unable to resolve frame index!");
}
-unsigned
+bool ARMBaseRegisterInfo::isFrameOffsetLegal(const MachineInstr *MI,
+ int64_t Offset) const {
+ const TargetInstrDesc &Desc = MI->getDesc();
+ unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
+ unsigned i = 0;
+
+ while (!MI->getOperand(i).isFI()) {
+ ++i;
+ assert(i < MI->getNumOperands() &&"Instr doesn't have FrameIndex operand!");
+ }
+
+ // AddrMode4 and AddrMode6 cannot handle any offset.
+ if (AddrMode == ARMII::AddrMode4 || AddrMode == ARMII::AddrMode6)
+ return Offset == 0;
+
+ unsigned NumBits = 0;
+ unsigned Scale = 1;
+ bool isSigned = true;
+ switch (AddrMode) {
+ case ARMII::AddrModeT2_i8:
+ case ARMII::AddrModeT2_i12:
+ // i8 supports only negative, and i12 supports only positive, so
+ // based on Offset sign, consider the appropriate instruction
+ Scale = 1;
+ if (Offset < 0) {
+ NumBits = 8;
+ Offset = -Offset;
+ } else {
+ NumBits = 12;
+ }
+ break;
+ case ARMII::AddrMode5:
+ // VFP address mode.
+ NumBits = 8;
+ Scale = 4;
+ break;
+ case ARMII::AddrMode_i12:
+ case ARMII::AddrMode2:
+ NumBits = 12;
+ break;
+ case ARMII::AddrMode3:
+ NumBits = 8;
+ break;
+ case ARMII::AddrModeT1_s:
+ NumBits = 5;
+ Scale = 4;
+ isSigned = false;
+ break;
+ default:
+ llvm_unreachable("Unsupported addressing mode!");
+ break;
+ }
+
+ Offset += getFrameIndexInstrOffset(MI, i);
+ // Make sure the offset is encodable for instructions that scale the
+ // immediate.
+ if ((Offset & (Scale-1)) != 0)
+ return false;
+
+ if (isSigned && Offset < 0)
+ Offset = -Offset;
+
+ unsigned Mask = (1 << NumBits) - 1;
+ if ((unsigned)Offset <= Mask * Scale)
+ return true;
+
+ return false;
+}
+
+void
ARMBaseRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
- int SPAdj, FrameIndexValue *Value,
- RegScavenger *RS) const {
+ int SPAdj, RegScavenger *RS) const {
unsigned i = 0;
MachineInstr &MI = *II;
MachineBasicBlock &MBB = *MI.getParent();
MachineFunction &MF = *MBB.getParent();
+ const ARMFrameInfo *TFI =
+ static_cast<const ARMFrameInfo*>(MF.getTarget().getFrameInfo());
ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
assert(!AFI->isThumb1OnlyFunction() &&
"This eliminateFrameIndex does not support Thumb1!");
int FrameIndex = MI.getOperand(i).getIndex();
unsigned FrameReg;
- int Offset = ResolveFrameIndexReference(MF, FrameIndex, FrameReg, SPAdj);
+ int Offset = TFI->ResolveFrameIndexReference(MF, FrameIndex, FrameReg, SPAdj);
// Special handling of dbg_value instructions.
if (MI.isDebugValue()) {
MI.getOperand(i). ChangeToRegister(FrameReg, false /*isDef*/);
MI.getOperand(i+1).ChangeToImmediate(Offset);
- return 0;
+ return;
}
// Modify MI as necessary to handle as much of 'Offset' as possible
Done = rewriteT2FrameIndex(MI, i, FrameReg, Offset, TII);
}
if (Done)
- return 0;
+ return;
// If we get here, the immediate doesn't fit into the instruction. We folded
// as much as possible above, handle the rest, providing a register that is
MI.getOperand(i).ChangeToRegister(FrameReg, false, false, false);
else {
ScratchReg = MF.getRegInfo().createVirtualRegister(ARM::GPRRegisterClass);
- if (Value) {
- Value->first = FrameReg; // use the frame register as a kind indicator
- Value->second = Offset;
- }
if (!AFI->isThumbFunction())
emitARMRegPlusImmediate(MBB, II, MI.getDebugLoc(), ScratchReg, FrameReg,
Offset, Pred, PredReg, TII);
Offset, Pred, PredReg, TII);
}
MI.getOperand(i).ChangeToRegister(ScratchReg, false, false, true);
- if (!ReuseFrameIndexVals)
- ScratchReg = 0;
- }
- return ScratchReg;
-}
-
-/// Move iterator past the next bunch of callee save load / store ops for
-/// the particular spill area (1: integer area 1, 2: integer area 2,
-/// 3: fp area, 0: don't care).
-static void movePastCSLoadStoreOps(MachineBasicBlock &MBB,
- MachineBasicBlock::iterator &MBBI,
- int Opc1, int Opc2, unsigned Area,
- const ARMSubtarget &STI) {
- while (MBBI != MBB.end() &&
- ((MBBI->getOpcode() == Opc1) || (MBBI->getOpcode() == Opc2)) &&
- MBBI->getOperand(1).isFI()) {
- if (Area != 0) {
- bool Done = false;
- unsigned Category = 0;
- switch (MBBI->getOperand(0).getReg()) {
- case ARM::R4: case ARM::R5: case ARM::R6: case ARM::R7:
- case ARM::LR:
- Category = 1;
- break;
- case ARM::R8: case ARM::R9: case ARM::R10: case ARM::R11:
- Category = STI.isTargetDarwin() ? 2 : 1;
- break;
- case ARM::D8: case ARM::D9: case ARM::D10: case ARM::D11:
- case ARM::D12: case ARM::D13: case ARM::D14: case ARM::D15:
- Category = 3;
- break;
- default:
- Done = true;
- break;
- }
- if (Done || Category != Area)
- break;
- }
-
- ++MBBI;
- }
-}
-
-void ARMBaseRegisterInfo::
-emitPrologue(MachineFunction &MF) const {
- MachineBasicBlock &MBB = MF.front();
- MachineBasicBlock::iterator MBBI = MBB.begin();
- MachineFrameInfo *MFI = MF.getFrameInfo();
- ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
- assert(!AFI->isThumb1OnlyFunction() &&
- "This emitPrologue does not support Thumb1!");
- bool isARM = !AFI->isThumbFunction();
- unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
- unsigned NumBytes = MFI->getStackSize();
- const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
- DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
-
- // Determine the sizes of each callee-save spill areas and record which frame
- // belongs to which callee-save spill areas.
- unsigned GPRCS1Size = 0, GPRCS2Size = 0, DPRCSSize = 0;
- int FramePtrSpillFI = 0;
-
- // Allocate the vararg register save area. This is not counted in NumBytes.
- if (VARegSaveSize)
- emitSPUpdate(isARM, MBB, MBBI, dl, TII, -VARegSaveSize);
-
- if (!AFI->hasStackFrame()) {
- if (NumBytes != 0)
- emitSPUpdate(isARM, MBB, MBBI, dl, TII, -NumBytes);
- return;
}
-
- for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
- unsigned Reg = CSI[i].getReg();
- int FI = CSI[i].getFrameIdx();
- switch (Reg) {
- case ARM::R4:
- case ARM::R5:
- case ARM::R6:
- case ARM::R7:
- case ARM::LR:
- if (Reg == FramePtr)
- FramePtrSpillFI = FI;
- AFI->addGPRCalleeSavedArea1Frame(FI);
- GPRCS1Size += 4;
- break;
- case ARM::R8:
- case ARM::R9:
- case ARM::R10:
- case ARM::R11:
- if (Reg == FramePtr)
- FramePtrSpillFI = FI;
- if (STI.isTargetDarwin()) {
- AFI->addGPRCalleeSavedArea2Frame(FI);
- GPRCS2Size += 4;
- } else {
- AFI->addGPRCalleeSavedArea1Frame(FI);
- GPRCS1Size += 4;
- }
- break;
- default:
- AFI->addDPRCalleeSavedAreaFrame(FI);
- DPRCSSize += 8;
- }
- }
-
- // Build the new SUBri to adjust SP for integer callee-save spill area 1.
- emitSPUpdate(isARM, MBB, MBBI, dl, TII, -GPRCS1Size);
- movePastCSLoadStoreOps(MBB, MBBI, ARM::STR, ARM::t2STRi12, 1, STI);
-
- // Set FP to point to the stack slot that contains the previous FP.
- // For Darwin, FP is R7, which has now been stored in spill area 1.
- // Otherwise, if this is not Darwin, all the callee-saved registers go
- // into spill area 1, including the FP in R11. In either case, it is
- // now safe to emit this assignment.
- bool HasFP = hasFP(MF);
- if (HasFP) {
- unsigned ADDriOpc = !AFI->isThumbFunction() ? ARM::ADDri : ARM::t2ADDri;
- MachineInstrBuilder MIB =
- BuildMI(MBB, MBBI, dl, TII.get(ADDriOpc), FramePtr)
- .addFrameIndex(FramePtrSpillFI).addImm(0);
- AddDefaultCC(AddDefaultPred(MIB));
- }
-
- // Build the new SUBri to adjust SP for integer callee-save spill area 2.
- emitSPUpdate(isARM, MBB, MBBI, dl, TII, -GPRCS2Size);
-
- // Build the new SUBri to adjust SP for FP callee-save spill area.
- movePastCSLoadStoreOps(MBB, MBBI, ARM::STR, ARM::t2STRi12, 2, STI);
- emitSPUpdate(isARM, MBB, MBBI, dl, TII, -DPRCSSize);
-
- // Determine starting offsets of spill areas.
- unsigned DPRCSOffset = NumBytes - (GPRCS1Size + GPRCS2Size + DPRCSSize);
- unsigned GPRCS2Offset = DPRCSOffset + DPRCSSize;
- unsigned GPRCS1Offset = GPRCS2Offset + GPRCS2Size;
- if (HasFP)
- AFI->setFramePtrSpillOffset(MFI->getObjectOffset(FramePtrSpillFI) +
- NumBytes);
- AFI->setGPRCalleeSavedArea1Offset(GPRCS1Offset);
- AFI->setGPRCalleeSavedArea2Offset(GPRCS2Offset);
- AFI->setDPRCalleeSavedAreaOffset(DPRCSOffset);
-
- movePastCSLoadStoreOps(MBB, MBBI, ARM::VSTRD, 0, 3, STI);
- NumBytes = DPRCSOffset;
- if (NumBytes) {
- // Adjust SP after all the callee-save spills.
- emitSPUpdate(isARM, MBB, MBBI, dl, TII, -NumBytes);
- if (HasFP)
- AFI->setShouldRestoreSPFromFP(true);
- }
-
- if (STI.isTargetELF() && hasFP(MF)) {
- MFI->setOffsetAdjustment(MFI->getOffsetAdjustment() -
- AFI->getFramePtrSpillOffset());
- AFI->setShouldRestoreSPFromFP(true);
- }
-
- AFI->setGPRCalleeSavedArea1Size(GPRCS1Size);
- AFI->setGPRCalleeSavedArea2Size(GPRCS2Size);
- AFI->setDPRCalleeSavedAreaSize(DPRCSSize);
-
- // If we need dynamic stack realignment, do it here.
- if (needsStackRealignment(MF)) {
- unsigned MaxAlign = MFI->getMaxAlignment();
- assert (!AFI->isThumb1OnlyFunction());
- if (!AFI->isThumbFunction()) {
- // Emit bic sp, sp, MaxAlign
- AddDefaultCC(AddDefaultPred(BuildMI(MBB, MBBI, dl,
- TII.get(ARM::BICri), ARM::SP)
- .addReg(ARM::SP, RegState::Kill)
- .addImm(MaxAlign-1)));
- } else {
- // We cannot use sp as source/dest register here, thus we're emitting the
- // following sequence:
- // mov r4, sp
- // bic r4, r4, MaxAlign
- // mov sp, r4
- // FIXME: It will be better just to find spare register here.
- BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVgpr2tgpr), ARM::R4)
- .addReg(ARM::SP, RegState::Kill);
- AddDefaultCC(AddDefaultPred(BuildMI(MBB, MBBI, dl,
- TII.get(ARM::t2BICri), ARM::R4)
- .addReg(ARM::R4, RegState::Kill)
- .addImm(MaxAlign-1)));
- BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVtgpr2gpr), ARM::SP)
- .addReg(ARM::R4, RegState::Kill);
- }
-
- AFI->setShouldRestoreSPFromFP(true);
- }
-
- // If the frame has variable sized objects then the epilogue must restore
- // the sp from fp.
- if (!AFI->shouldRestoreSPFromFP() && MFI->hasVarSizedObjects())
- AFI->setShouldRestoreSPFromFP(true);
-}
-
-static bool isCalleeSavedRegister(unsigned Reg, const unsigned *CSRegs) {
- for (unsigned i = 0; CSRegs[i]; ++i)
- if (Reg == CSRegs[i])
- return true;
- return false;
-}
-
-static bool isCSRestore(MachineInstr *MI,
- const ARMBaseInstrInfo &TII,
- const unsigned *CSRegs) {
- return ((MI->getOpcode() == (int)ARM::VLDRD ||
- MI->getOpcode() == (int)ARM::LDR ||
- MI->getOpcode() == (int)ARM::t2LDRi12) &&
- MI->getOperand(1).isFI() &&
- isCalleeSavedRegister(MI->getOperand(0).getReg(), CSRegs));
-}
-
-void ARMBaseRegisterInfo::
-emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const {
- MachineBasicBlock::iterator MBBI = prior(MBB.end());
- assert(MBBI->getDesc().isReturn() &&
- "Can only insert epilog into returning blocks");
- unsigned RetOpcode = MBBI->getOpcode();
- DebugLoc dl = MBBI->getDebugLoc();
- MachineFrameInfo *MFI = MF.getFrameInfo();
- ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
- assert(!AFI->isThumb1OnlyFunction() &&
- "This emitEpilogue does not support Thumb1!");
- bool isARM = !AFI->isThumbFunction();
-
- unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
- int NumBytes = (int)MFI->getStackSize();
-
- if (!AFI->hasStackFrame()) {
- if (NumBytes != 0)
- emitSPUpdate(isARM, MBB, MBBI, dl, TII, NumBytes);
- } else {
- // Unwind MBBI to point to first LDR / VLDRD.
- const unsigned *CSRegs = getCalleeSavedRegs();
- if (MBBI != MBB.begin()) {
- do
- --MBBI;
- while (MBBI != MBB.begin() && isCSRestore(MBBI, TII, CSRegs));
- if (!isCSRestore(MBBI, TII, CSRegs))
- ++MBBI;
- }
-
- // Move SP to start of FP callee save spill area.
- NumBytes -= (AFI->getGPRCalleeSavedArea1Size() +
- AFI->getGPRCalleeSavedArea2Size() +
- AFI->getDPRCalleeSavedAreaSize());
-
- // Reset SP based on frame pointer only if the stack frame extends beyond
- // frame pointer stack slot or target is ELF and the function has FP.
- if (AFI->shouldRestoreSPFromFP()) {
- NumBytes = AFI->getFramePtrSpillOffset() - NumBytes;
- if (NumBytes) {
- if (isARM)
- emitARMRegPlusImmediate(MBB, MBBI, dl, ARM::SP, FramePtr, -NumBytes,
- ARMCC::AL, 0, TII);
- else
- emitT2RegPlusImmediate(MBB, MBBI, dl, ARM::SP, FramePtr, -NumBytes,
- ARMCC::AL, 0, TII);
- } else {
- // Thumb2 or ARM.
- if (isARM)
- BuildMI(MBB, MBBI, dl, TII.get(ARM::MOVr), ARM::SP)
- .addReg(FramePtr).addImm((unsigned)ARMCC::AL).addReg(0).addReg(0);
- else
- BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVgpr2gpr), ARM::SP)
- .addReg(FramePtr);
- }
- } else if (NumBytes)
- emitSPUpdate(isARM, MBB, MBBI, dl, TII, NumBytes);
-
- // Move SP to start of integer callee save spill area 2.
- movePastCSLoadStoreOps(MBB, MBBI, ARM::VLDRD, 0, 3, STI);
- emitSPUpdate(isARM, MBB, MBBI, dl, TII, AFI->getDPRCalleeSavedAreaSize());
-
- // Move SP to start of integer callee save spill area 1.
- movePastCSLoadStoreOps(MBB, MBBI, ARM::LDR, ARM::t2LDRi12, 2, STI);
- emitSPUpdate(isARM, MBB, MBBI, dl, TII, AFI->getGPRCalleeSavedArea2Size());
-
- // Move SP to SP upon entry to the function.
- movePastCSLoadStoreOps(MBB, MBBI, ARM::LDR, ARM::t2LDRi12, 1, STI);
- emitSPUpdate(isARM, MBB, MBBI, dl, TII, AFI->getGPRCalleeSavedArea1Size());
- }
-
- if (RetOpcode == ARM::TCRETURNdi || RetOpcode == ARM::TCRETURNdiND ||
- RetOpcode == ARM::TCRETURNri || RetOpcode == ARM::TCRETURNriND) {
- // Tail call return: adjust the stack pointer and jump to callee.
- MBBI = prior(MBB.end());
- MachineOperand &JumpTarget = MBBI->getOperand(0);
-
- // Jump to label or value in register.
- if (RetOpcode == ARM::TCRETURNdi) {
- BuildMI(MBB, MBBI, dl,
- TII.get(STI.isThumb() ? ARM::TAILJMPdt : ARM::TAILJMPd)).
- addGlobalAddress(JumpTarget.getGlobal(), JumpTarget.getOffset(),
- JumpTarget.getTargetFlags());
- } else if (RetOpcode == ARM::TCRETURNdiND) {
- BuildMI(MBB, MBBI, dl,
- TII.get(STI.isThumb() ? ARM::TAILJMPdNDt : ARM::TAILJMPdND)).
- addGlobalAddress(JumpTarget.getGlobal(), JumpTarget.getOffset(),
- JumpTarget.getTargetFlags());
- } else if (RetOpcode == ARM::TCRETURNri) {
- BuildMI(MBB, MBBI, dl, TII.get(ARM::TAILJMPr)).
- addReg(JumpTarget.getReg(), RegState::Kill);
- } else if (RetOpcode == ARM::TCRETURNriND) {
- BuildMI(MBB, MBBI, dl, TII.get(ARM::TAILJMPrND)).
- addReg(JumpTarget.getReg(), RegState::Kill);
- }
-
- MachineInstr *NewMI = prior(MBBI);
- for (unsigned i = 1, e = MBBI->getNumOperands(); i != e; ++i)
- NewMI->addOperand(MBBI->getOperand(i));
-
- // Delete the pseudo instruction TCRETURN.
- MBB.erase(MBBI);
- }
-
- if (VARegSaveSize)
- emitSPUpdate(isARM, MBB, MBBI, dl, TII, VARegSaveSize);
}
#include "ARMGenRegisterInfo.inc"
projects / oota-llvm.git / blobdiff