1 //===-- HexagonFrameLowering.cpp - Define frame lowering ------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
9 //===----------------------------------------------------------------------===//
11 #define DEBUG_TYPE "hexagon-pei"
13 #include "HexagonFrameLowering.h"
15 #include "HexagonInstrInfo.h"
16 #include "HexagonMachineFunctionInfo.h"
17 #include "HexagonRegisterInfo.h"
18 #include "HexagonSubtarget.h"
19 #include "HexagonTargetMachine.h"
20 #include "llvm/ADT/BitVector.h"
21 #include "llvm/ADT/PostOrderIterator.h"
22 #include "llvm/ADT/STLExtras.h"
23 #include "llvm/CodeGen/MachineDominators.h"
24 #include "llvm/CodeGen/MachineInstrBuilder.h"
25 #include "llvm/CodeGen/MachineFunction.h"
26 #include "llvm/CodeGen/MachineFunctionPass.h"
27 #include "llvm/CodeGen/MachineInstrBuilder.h"
28 #include "llvm/CodeGen/MachineModuleInfo.h"
29 #include "llvm/CodeGen/MachinePostDominators.h"
30 #include "llvm/CodeGen/MachineRegisterInfo.h"
31 #include "llvm/CodeGen/RegisterScavenging.h"
32 #include "llvm/IR/Function.h"
33 #include "llvm/IR/Type.h"
34 #include "llvm/Support/CommandLine.h"
35 #include "llvm/Support/Debug.h"
36 #include "llvm/Support/raw_ostream.h"
37 #include "llvm/Target/TargetInstrInfo.h"
38 #include "llvm/Target/TargetMachine.h"
39 #include "llvm/Target/TargetOptions.h"
41 // Hexagon stack frame layout as defined by the ABI:
47 // SP during function's FP during function's |
48 // +-- runtime (top of stack) runtime (bottom) --+ |
50 // --++---------------------+------------------+-----------------++-+-------
51 // | parameter area for | variable-size | fixed-size |LR| arg
52 // | called functions | local objects | local objects |FP|
53 // --+----------------------+------------------+-----------------+--+-------
54 // <- size known -> <- size unknown -> <- size known ->
56 // Low address High address
61 // - In any circumstances, the outgoing function arguments are always accessi-
62 // ble using the SP, and the incoming arguments are accessible using the FP.
63 // - If the local objects are not aligned, they can always be accessed using
65 // - If there are no variable-sized objects, the local objects can always be
66 // accessed using the SP, regardless whether they are aligned or not. (The
67 // alignment padding will be at the bottom of the stack (highest address),
68 // and so the offset with respect to the SP will be known at the compile-
71 // The only complication occurs if there are both, local aligned objects, and
72 // dynamically allocated (variable-sized) objects. The alignment pad will be
73 // placed between the FP and the local objects, thus preventing the use of the
74 // FP to access the local objects. At the same time, the variable-sized objects
75 // will be between the SP and the local objects, thus introducing an unknown
76 // distance from the SP to the locals.
78 // To avoid this problem, a new register is created that holds the aligned
79 // address of the bottom of the stack, referred in the sources as AP (aligned
80 // pointer). The AP will be equal to "FP-p", where "p" is the smallest pad
81 // that aligns AP to the required boundary (a maximum of the alignments of
82 // all stack objects, fixed- and variable-sized). All local objects[1] will
83 // then use AP as the base pointer.
84 // [1] The exception is with "fixed" stack objects. "Fixed" stack objects get
85 // their name from being allocated at fixed locations on the stack, relative
86 // to the FP. In the presence of dynamic allocation and local alignment, such
87 // objects can only be accessed through the FP.
89 // Illustration of the AP:
92 // ---------------+---------------------+-----+-----------------------++-+--
93 // Rest of the | Local stack objects | Pad | Fixed stack objects |LR|
94 // stack frame | (aligned) | | (CSR, spills, etc.) |FP|
95 // ---------------+---------------------+-----+-----------------+-----+--+--
96 // |<-- Multiple of the -->|
97 // stack alignment +-- AP
99 // The AP is set up at the beginning of the function. Since it is not a dedi-
100 // cated (reserved) register, it needs to be kept live throughout the function
101 // to be available as the base register for local object accesses.
102 // Normally, an address of a stack objects is obtained by a pseudo-instruction
103 // TFR_FI. To access local objects with the AP register present, a different
104 // pseudo-instruction needs to be used: TFR_FIA. The TFR_FIA takes one extra
105 // argument compared to TFR_FI: the first input register is the AP register.
106 // This keeps the register live between its definition and its uses.
108 // The AP register is originally set up using pseudo-instruction ALIGNA:
111 // A - required stack alignment
112 // The alignment value must be the maximum of all alignments required by
115 // The dynamic allocation uses a pseudo-instruction ALLOCA:
118 // Rd - address of the allocated space
119 // Rs - minimum size (the actual allocated can be larger to accommodate
121 // A - required alignment
124 using namespace llvm;
126 static cl::opt<bool> DisableDeallocRet("disable-hexagon-dealloc-ret",
127 cl::Hidden, cl::desc("Disable Dealloc Return for Hexagon target"));
130 static cl::opt<int> NumberScavengerSlots("number-scavenger-slots",
131 cl::Hidden, cl::desc("Set the number of scavenger slots"), cl::init(2),
134 static cl::opt<int> SpillFuncThreshold("spill-func-threshold",
135 cl::Hidden, cl::desc("Specify O2(not Os) spill func threshold"),
136 cl::init(6), cl::ZeroOrMore);
138 static cl::opt<int> SpillFuncThresholdOs("spill-func-threshold-Os",
139 cl::Hidden, cl::desc("Specify Os spill func threshold"),
140 cl::init(1), cl::ZeroOrMore);
142 static cl::opt<bool> EnableShrinkWrapping("hexagon-shrink-frame",
143 cl::init(true), cl::Hidden, cl::ZeroOrMore,
144 cl::desc("Enable stack frame shrink wrapping"));
146 static cl::opt<unsigned> ShrinkLimit("shrink-frame-limit", cl::init(UINT_MAX),
147 cl::Hidden, cl::ZeroOrMore, cl::desc("Max count of stack frame "
151 /// Map a register pair Reg to the subregister that has the greater "number",
152 /// i.e. D3 (aka R7:6) will be mapped to R7, etc.
153 unsigned getMax32BitSubRegister(unsigned Reg, const TargetRegisterInfo &TRI,
155 if (Reg < Hexagon::D0 || Reg > Hexagon::D15)
159 for (MCSubRegIterator SubRegs(Reg, &TRI); SubRegs.isValid(); ++SubRegs) {
161 if (*SubRegs > RegNo)
164 if (!RegNo || *SubRegs < RegNo)
171 /// Returns the callee saved register with the largest id in the vector.
172 unsigned getMaxCalleeSavedReg(const std::vector<CalleeSavedInfo> &CSI,
173 const TargetRegisterInfo &TRI) {
174 assert(Hexagon::R1 > 0 &&
175 "Assume physical registers are encoded as positive integers");
179 unsigned Max = getMax32BitSubRegister(CSI[0].getReg(), TRI);
180 for (unsigned I = 1, E = CSI.size(); I < E; ++I) {
181 unsigned Reg = getMax32BitSubRegister(CSI[I].getReg(), TRI);
188 /// Checks if the basic block contains any instruction that needs a stack
189 /// frame to be already in place.
190 bool needsStackFrame(const MachineBasicBlock &MBB, const BitVector &CSR) {
191 for (auto &I : MBB) {
192 const MachineInstr *MI = &I;
195 unsigned Opc = MI->getOpcode();
197 case Hexagon::ALLOCA:
198 case Hexagon::ALIGNA:
203 // Check individual operands.
204 for (const MachineOperand &MO : MI->operands()) {
205 // While the presence of a frame index does not prove that a stack
206 // frame will be required, all frame indexes should be within alloc-
207 // frame/deallocframe. Otherwise, the code that translates a frame
208 // index into an offset would have to be aware of the placement of
209 // the frame creation/destruction instructions.
214 unsigned R = MO.getReg();
215 // Virtual registers will need scavenging, which then may require
217 if (TargetRegisterInfo::isVirtualRegister(R))
226 /// Returns true if MBB has a machine instructions that indicates a tail call
228 bool hasTailCall(const MachineBasicBlock &MBB) {
229 MachineBasicBlock::const_iterator I = MBB.getLastNonDebugInstr();
230 unsigned RetOpc = I->getOpcode();
231 return RetOpc == Hexagon::TCRETURNi || RetOpc == Hexagon::TCRETURNr;
234 /// Returns true if MBB contains an instruction that returns.
235 bool hasReturn(const MachineBasicBlock &MBB) {
236 for (auto I = MBB.getFirstTerminator(), E = MBB.end(); I != E; ++I)
244 /// Implements shrink-wrapping of the stack frame. By default, stack frame
245 /// is created in the function entry block, and is cleaned up in every block
246 /// that returns. This function finds alternate blocks: one for the frame
247 /// setup (prolog) and one for the cleanup (epilog).
248 void HexagonFrameLowering::findShrunkPrologEpilog(MachineFunction &MF,
249 MachineBasicBlock *&PrologB, MachineBasicBlock *&EpilogB) const {
250 static unsigned ShrinkCounter = 0;
252 if (ShrinkLimit.getPosition()) {
253 if (ShrinkCounter >= ShrinkLimit)
258 auto &HST = static_cast<const HexagonSubtarget&>(MF.getSubtarget());
259 auto &HRI = *HST.getRegisterInfo();
261 MachineDominatorTree MDT;
262 MDT.runOnMachineFunction(MF);
263 MachinePostDominatorTree MPT;
264 MPT.runOnMachineFunction(MF);
266 typedef DenseMap<unsigned,unsigned> UnsignedMap;
268 typedef ReversePostOrderTraversal<const MachineFunction*> RPOTType;
271 for (RPOTType::rpo_iterator I = RPOT.begin(), E = RPOT.end(); I != E; ++I)
272 RPO[(*I)->getNumber()] = RPON++;
274 // Don't process functions that have loops, at least for now. Placement
275 // of prolog and epilog must take loop structure into account. For simpli-
276 // city don't do it right now.
278 unsigned BN = RPO[I.getNumber()];
279 for (auto SI = I.succ_begin(), SE = I.succ_end(); SI != SE; ++SI) {
280 // If found a back-edge, return.
281 if (RPO[(*SI)->getNumber()] <= BN)
286 // Collect the set of blocks that need a stack frame to execute. Scan
287 // each block for uses/defs of callee-saved registers, calls, etc.
288 SmallVector<MachineBasicBlock*,16> SFBlocks;
289 BitVector CSR(Hexagon::NUM_TARGET_REGS);
290 for (const MCPhysReg *P = HRI.getCalleeSavedRegs(&MF); *P; ++P)
294 if (needsStackFrame(I, CSR))
295 SFBlocks.push_back(&I);
298 dbgs() << "Blocks needing SF: {";
299 for (auto &B : SFBlocks)
300 dbgs() << " BB#" << B->getNumber();
304 if (SFBlocks.empty())
307 // Pick a common dominator and a common post-dominator.
308 MachineBasicBlock *DomB = SFBlocks[0];
309 for (unsigned i = 1, n = SFBlocks.size(); i < n; ++i) {
310 DomB = MDT.findNearestCommonDominator(DomB, SFBlocks[i]);
314 MachineBasicBlock *PDomB = SFBlocks[0];
315 for (unsigned i = 1, n = SFBlocks.size(); i < n; ++i) {
316 PDomB = MPT.findNearestCommonDominator(PDomB, SFBlocks[i]);
321 dbgs() << "Computed dom block: BB#";
322 if (DomB) dbgs() << DomB->getNumber();
323 else dbgs() << "<null>";
324 dbgs() << ", computed pdom block: BB#";
325 if (PDomB) dbgs() << PDomB->getNumber();
326 else dbgs() << "<null>";
332 // Make sure that DomB dominates PDomB and PDomB post-dominates DomB.
333 if (!MDT.dominates(DomB, PDomB)) {
334 DEBUG(dbgs() << "Dom block does not dominate pdom block\n");
337 if (!MPT.dominates(PDomB, DomB)) {
338 DEBUG(dbgs() << "PDom block does not post-dominate dom block\n");
342 // Finally, everything seems right.
347 /// Perform most of the PEI work here:
348 /// - saving/restoring of the callee-saved registers,
349 /// - stack frame creation and destruction.
350 /// Normally, this work is distributed among various functions, but doing it
351 /// in one place allows shrink-wrapping of the stack frame.
352 void HexagonFrameLowering::emitPrologue(MachineFunction &MF,
353 MachineBasicBlock &MBB) const {
354 auto &HST = static_cast<const HexagonSubtarget&>(MF.getSubtarget());
355 auto &HRI = *HST.getRegisterInfo();
357 assert(&MF.front() == &MBB && "Shrink-wrapping not yet supported");
358 MachineFrameInfo *MFI = MF.getFrameInfo();
359 const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
361 MachineBasicBlock *PrologB = &MF.front(), *EpilogB = nullptr;
362 if (EnableShrinkWrapping)
363 findShrunkPrologEpilog(MF, PrologB, EpilogB);
365 insertCSRSpillsInBlock(*PrologB, CSI, HRI);
366 insertPrologueInBlock(*PrologB);
369 insertCSRRestoresInBlock(*EpilogB, CSI, HRI);
370 insertEpilogueInBlock(*EpilogB);
373 if (!B.empty() && B.back().isReturn())
374 insertCSRRestoresInBlock(B, CSI, HRI);
377 if (!B.empty() && B.back().isReturn())
378 insertEpilogueInBlock(B);
383 void HexagonFrameLowering::insertPrologueInBlock(MachineBasicBlock &MBB) const {
384 MachineFunction &MF = *MBB.getParent();
385 MachineFrameInfo *MFI = MF.getFrameInfo();
386 MachineModuleInfo &MMI = MF.getMMI();
387 MachineBasicBlock::iterator MBBI = MBB.begin();
388 auto &HTM = static_cast<const HexagonTargetMachine&>(MF.getTarget());
389 auto &HST = static_cast<const HexagonSubtarget&>(MF.getSubtarget());
390 auto &HII = *HST.getInstrInfo();
391 auto &HRI = *HST.getRegisterInfo();
394 unsigned MaxAlign = std::max(MFI->getMaxAlignment(), getStackAlignment());
396 // Calculate the total stack frame size.
397 // Get the number of bytes to allocate from the FrameInfo.
398 unsigned FrameSize = MFI->getStackSize();
399 // Round up the max call frame size to the max alignment on the stack.
400 unsigned MaxCFA = RoundUpToAlignment(MFI->getMaxCallFrameSize(), MaxAlign);
401 MFI->setMaxCallFrameSize(MaxCFA);
403 FrameSize = MaxCFA + RoundUpToAlignment(FrameSize, MaxAlign);
404 MFI->setStackSize(FrameSize);
406 bool AlignStack = (MaxAlign > getStackAlignment());
408 // Check if frame moves are needed for EH.
409 bool needsFrameMoves = MMI.hasDebugInfo() ||
410 MF.getFunction()->needsUnwindTableEntry();
412 // Get the number of bytes to allocate from the FrameInfo.
413 unsigned NumBytes = MFI->getStackSize();
414 unsigned SP = HRI.getStackRegister();
415 unsigned MaxCF = MFI->getMaxCallFrameSize();
416 MachineBasicBlock::iterator InsertPt = MBB.begin();
418 auto *FuncInfo = MF.getInfo<HexagonMachineFunctionInfo>();
419 auto &AdjustRegs = FuncInfo->getAllocaAdjustInsts();
421 for (auto MI : AdjustRegs) {
422 assert((MI->getOpcode() == Hexagon::ALLOCA) && "Expected alloca");
423 expandAlloca(MI, HII, SP, MaxCF);
424 MI->eraseFromParent();
428 // Only insert ALLOCFRAME if we need to or at -O0 for the debugger. Think
429 // that this shouldn't be required, but doing so now because gcc does and
430 // gdb can't break at the start of the function without it. Will remove if
431 // this turns out to be a gdb bug.
433 bool NoOpt = (HTM.getOptLevel() == CodeGenOpt::None);
434 if (!NoOpt && !FuncInfo->hasClobberLR() && !hasFP(MF))
437 // Check for overflow.
438 // Hexagon_TODO: Ugh! hardcoding. Is there an API that can be used?
439 const unsigned int ALLOCFRAME_MAX = 16384;
441 // Create a dummy memory operand to avoid allocframe from being treated as
442 // a volatile memory reference.
443 MachineMemOperand *MMO =
444 MF.getMachineMemOperand(MachinePointerInfo(), MachineMemOperand::MOStore,
447 if (NumBytes >= ALLOCFRAME_MAX) {
448 // Emit allocframe(#0).
449 BuildMI(MBB, InsertPt, dl, HII.get(Hexagon::S2_allocframe))
453 // Subtract offset from frame pointer.
454 // We use a caller-saved non-parameter register for that.
455 unsigned CallerSavedReg = HRI.getFirstCallerSavedNonParamReg();
456 BuildMI(MBB, InsertPt, dl, HII.get(Hexagon::CONST32_Int_Real),
457 CallerSavedReg).addImm(NumBytes);
458 BuildMI(MBB, InsertPt, dl, HII.get(Hexagon::A2_sub), SP)
460 .addReg(CallerSavedReg);
462 BuildMI(MBB, InsertPt, dl, HII.get(Hexagon::S2_allocframe))
468 BuildMI(MBB, InsertPt, dl, HII.get(Hexagon::A2_andir), SP)
470 .addImm(-int64_t(MaxAlign));
473 if (needsFrameMoves) {
474 std::vector<MCCFIInstruction> Instructions = MMI.getFrameInstructions();
475 MCSymbol *FrameLabel = MMI.getContext().createTempSymbol();
477 // Advance CFA. DW_CFA_def_cfa
478 unsigned DwFPReg = HRI.getDwarfRegNum(HRI.getFrameRegister(), true);
479 unsigned DwRAReg = HRI.getDwarfRegNum(HRI.getRARegister(), true);
482 unsigned CFIIndex = MMI.addFrameInst(MCCFIInstruction::createDefCfa(
483 FrameLabel, DwFPReg, -8));
484 BuildMI(MBB, MBBI, dl, HII.get(TargetOpcode::CFI_INSTRUCTION))
485 .addCFIIndex(CFIIndex);
487 // R31 (return addr) = CFA - #4
488 CFIIndex = MMI.addFrameInst(MCCFIInstruction::createOffset(
489 FrameLabel, DwRAReg, -4));
490 BuildMI(MBB, MBBI, dl, HII.get(TargetOpcode::CFI_INSTRUCTION))
491 .addCFIIndex(CFIIndex);
493 // R30 (frame ptr) = CFA - #8)
494 CFIIndex = MMI.addFrameInst(MCCFIInstruction::createOffset(
495 FrameLabel, DwFPReg, -8));
496 BuildMI(MBB, MBBI, dl, HII.get(TargetOpcode::CFI_INSTRUCTION))
497 .addCFIIndex(CFIIndex);
499 unsigned int regsToMove[] = {
500 Hexagon::R1, Hexagon::R0, Hexagon::R3, Hexagon::R2,
501 Hexagon::R17, Hexagon::R16, Hexagon::R19, Hexagon::R18,
502 Hexagon::R21, Hexagon::R20, Hexagon::R23, Hexagon::R22,
503 Hexagon::R25, Hexagon::R24, Hexagon::R27, Hexagon::R26,
504 Hexagon::D0, Hexagon::D1, Hexagon::D8, Hexagon::D9, Hexagon::D10,
505 Hexagon::D11, Hexagon::D12, Hexagon::D13, Hexagon::NoRegister
508 const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
510 for (unsigned i = 0; regsToMove[i] != Hexagon::NoRegister; ++i) {
511 for (unsigned I = 0, E = CSI.size(); I < E; ++I) {
512 if (CSI[I].getReg() == regsToMove[i]) {
513 // Subtract 8 to make room for R30 and R31, which are added above.
514 int64_t Offset = getFrameIndexOffset(MF, CSI[I].getFrameIdx()) - 8;
516 if (regsToMove[i] < Hexagon::D0 || regsToMove[i] > Hexagon::D15) {
517 unsigned DwarfReg = HRI.getDwarfRegNum(regsToMove[i], true);
518 unsigned CFIIndex = MMI.addFrameInst(
519 MCCFIInstruction::createOffset(FrameLabel,
521 BuildMI(MBB, MBBI, dl, HII.get(TargetOpcode::CFI_INSTRUCTION))
522 .addCFIIndex(CFIIndex);
524 // Split the double regs into subregs, and generate appropriate
526 // The only reason, we are split double regs is, llvm-mc does not
527 // understand paired registers for cfi_offset.
528 // Eg .cfi_offset r1:0, -64
529 unsigned HiReg = getMax32BitSubRegister(regsToMove[i], HRI);
530 unsigned LoReg = getMax32BitSubRegister(regsToMove[i], HRI, false);
531 unsigned HiDwarfReg = HRI.getDwarfRegNum(HiReg, true);
532 unsigned LoDwarfReg = HRI.getDwarfRegNum(LoReg, true);
533 unsigned HiCFIIndex = MMI.addFrameInst(
534 MCCFIInstruction::createOffset(FrameLabel,
535 HiDwarfReg, Offset+4));
536 BuildMI(MBB, MBBI, dl, HII.get(TargetOpcode::CFI_INSTRUCTION))
537 .addCFIIndex(HiCFIIndex);
538 unsigned LoCFIIndex = MMI.addFrameInst(
539 MCCFIInstruction::createOffset(FrameLabel,
540 LoDwarfReg, Offset));
541 BuildMI(MBB, MBBI, dl, HII.get(TargetOpcode::CFI_INSTRUCTION))
542 .addCFIIndex(LoCFIIndex);
551 void HexagonFrameLowering::insertEpilogueInBlock(MachineBasicBlock &MBB) const {
552 MachineFunction &MF = *MBB.getParent();
554 // Only insert deallocframe if we need to. Also at -O0. See comment
555 // in insertPrologueInBlock above.
557 if (!hasFP(MF) && MF.getTarget().getOptLevel() != CodeGenOpt::None)
560 auto &HST = static_cast<const HexagonSubtarget&>(MF.getSubtarget());
561 auto &HII = *HST.getInstrInfo();
562 auto &HRI = *HST.getRegisterInfo();
563 unsigned SP = HRI.getStackRegister();
565 MachineInstr *RetI = nullptr;
566 for (auto &I : MBB) {
572 unsigned RetOpc = RetI ? RetI->getOpcode() : 0;
574 MachineBasicBlock::iterator InsertPt = MBB.getFirstTerminator();
576 if (InsertPt != MBB.end())
577 DL = InsertPt->getDebugLoc();
578 else if (!MBB.empty())
579 DL = std::prev(MBB.end())->getDebugLoc();
582 if (RetOpc == Hexagon::EH_RETURN_JMPR) {
583 BuildMI(MBB, InsertPt, DL, HII.get(Hexagon::L2_deallocframe));
584 BuildMI(MBB, InsertPt, DL, HII.get(Hexagon::A2_add), SP)
586 .addReg(Hexagon::R28);
590 // Check for RESTORE_DEALLOC_RET* tail call. Don't emit an extra dealloc-
591 // frame instruction if we encounter it.
592 if (RetOpc == Hexagon::RESTORE_DEALLOC_RET_JMP_V4) {
593 MachineBasicBlock::iterator It = RetI;
595 // Delete all instructions after the RESTORE (except labels).
596 while (It != MBB.end()) {
605 // It is possible that the restoring code is a call to a library function.
606 // All of the restore* functions include "deallocframe", so we need to make
607 // sure that we don't add an extra one.
608 bool NeedsDeallocframe = true;
609 if (!MBB.empty() && InsertPt != MBB.begin()) {
610 MachineBasicBlock::iterator PrevIt = std::prev(InsertPt);
611 unsigned COpc = PrevIt->getOpcode();
612 if (COpc == Hexagon::RESTORE_DEALLOC_BEFORE_TAILCALL_V4)
613 NeedsDeallocframe = false;
616 if (!NeedsDeallocframe)
618 // If the returning instruction is JMPret, replace it with dealloc_return,
619 // otherwise just add deallocframe. The function could be returning via a
621 if (RetOpc != Hexagon::JMPret || DisableDeallocRet) {
622 BuildMI(MBB, InsertPt, DL, HII.get(Hexagon::L2_deallocframe));
625 unsigned NewOpc = Hexagon::L4_return;
626 MachineInstr *NewI = BuildMI(MBB, RetI, DL, HII.get(NewOpc));
627 // Transfer the function live-out registers.
628 NewI->copyImplicitOps(MF, RetI);
633 bool HexagonFrameLowering::hasFP(const MachineFunction &MF) const {
634 const MachineFrameInfo *MFI = MF.getFrameInfo();
635 const HexagonMachineFunctionInfo *FuncInfo =
636 MF.getInfo<HexagonMachineFunctionInfo>();
637 return MFI->hasCalls() || MFI->getStackSize() > 0 ||
638 FuncInfo->hasClobberLR();
649 getSpillFunctionFor(unsigned MaxReg, SpillKind SpillType) {
650 const char * V4SpillToMemoryFunctions[] = {
651 "__save_r16_through_r17",
652 "__save_r16_through_r19",
653 "__save_r16_through_r21",
654 "__save_r16_through_r23",
655 "__save_r16_through_r25",
656 "__save_r16_through_r27" };
658 const char * V4SpillFromMemoryFunctions[] = {
659 "__restore_r16_through_r17_and_deallocframe",
660 "__restore_r16_through_r19_and_deallocframe",
661 "__restore_r16_through_r21_and_deallocframe",
662 "__restore_r16_through_r23_and_deallocframe",
663 "__restore_r16_through_r25_and_deallocframe",
664 "__restore_r16_through_r27_and_deallocframe" };
666 const char * V4SpillFromMemoryTailcallFunctions[] = {
667 "__restore_r16_through_r17_and_deallocframe_before_tailcall",
668 "__restore_r16_through_r19_and_deallocframe_before_tailcall",
669 "__restore_r16_through_r21_and_deallocframe_before_tailcall",
670 "__restore_r16_through_r23_and_deallocframe_before_tailcall",
671 "__restore_r16_through_r25_and_deallocframe_before_tailcall",
672 "__restore_r16_through_r27_and_deallocframe_before_tailcall"
675 const char **SpillFunc = nullptr;
679 SpillFunc = V4SpillToMemoryFunctions;
682 SpillFunc = V4SpillFromMemoryFunctions;
684 case SK_FromMemTailcall:
685 SpillFunc = V4SpillFromMemoryTailcallFunctions;
688 assert(SpillFunc && "Unknown spill kind");
690 // Spill all callee-saved registers up to the highest register used.
705 llvm_unreachable("Unhandled maximum callee save register");
710 /// Adds all callee-saved registers up to MaxReg to the instruction.
711 static void addCalleeSaveRegistersAsImpOperand(MachineInstr *Inst,
712 unsigned MaxReg, bool IsDef) {
713 // Add the callee-saved registers as implicit uses.
714 for (unsigned R = Hexagon::R16; R <= MaxReg; ++R) {
715 MachineOperand ImpUse = MachineOperand::CreateReg(R, IsDef, true);
716 Inst->addOperand(ImpUse);
721 int HexagonFrameLowering::getFrameIndexOffset(const MachineFunction &MF,
723 return MF.getFrameInfo()->getObjectOffset(FI);
727 bool HexagonFrameLowering::insertCSRSpillsInBlock(MachineBasicBlock &MBB,
728 const CSIVect &CSI, const HexagonRegisterInfo &HRI) const {
732 MachineBasicBlock::iterator MI = MBB.begin();
733 MachineFunction &MF = *MBB.getParent();
734 const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo();
736 if (useSpillFunction(MF, CSI)) {
737 unsigned MaxReg = getMaxCalleeSavedReg(CSI, HRI);
738 const char *SpillFun = getSpillFunctionFor(MaxReg, SK_ToMem);
739 // Call spill function.
740 DebugLoc DL = MI != MBB.end() ? MI->getDebugLoc() : DebugLoc();
741 MachineInstr *SaveRegsCall =
742 BuildMI(MBB, MI, DL, TII.get(Hexagon::SAVE_REGISTERS_CALL_V4))
743 .addExternalSymbol(SpillFun);
744 // Add callee-saved registers as use.
745 addCalleeSaveRegistersAsImpOperand(SaveRegsCall, MaxReg, false);
746 // Add live in registers.
747 for (unsigned I = 0; I < CSI.size(); ++I)
748 MBB.addLiveIn(CSI[I].getReg());
752 for (unsigned i = 0, n = CSI.size(); i < n; ++i) {
753 unsigned Reg = CSI[i].getReg();
754 // Add live in registers. We treat eh_return callee saved register r0 - r3
755 // specially. They are not really callee saved registers as they are not
756 // supposed to be killed.
757 bool IsKill = !HRI.isEHReturnCalleeSaveReg(Reg);
758 int FI = CSI[i].getFrameIdx();
759 const TargetRegisterClass *RC = HRI.getMinimalPhysRegClass(Reg);
760 TII.storeRegToStackSlot(MBB, MI, Reg, IsKill, FI, RC, &HRI);
768 bool HexagonFrameLowering::insertCSRRestoresInBlock(MachineBasicBlock &MBB,
769 const CSIVect &CSI, const HexagonRegisterInfo &HRI) const {
773 MachineBasicBlock::iterator MI = MBB.getFirstTerminator();
774 MachineFunction &MF = *MBB.getParent();
775 const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo();
777 if (useRestoreFunction(MF, CSI)) {
778 bool HasTC = hasTailCall(MBB) || !hasReturn(MBB);
779 unsigned MaxR = getMaxCalleeSavedReg(CSI, HRI);
780 SpillKind Kind = HasTC ? SK_FromMemTailcall : SK_FromMem;
781 const char *RestoreFn = getSpillFunctionFor(MaxR, Kind);
783 // Call spill function.
784 DebugLoc DL = MI != MBB.end() ? MI->getDebugLoc()
785 : MBB.getLastNonDebugInstr()->getDebugLoc();
786 MachineInstr *DeallocCall = nullptr;
789 unsigned ROpc = Hexagon::RESTORE_DEALLOC_BEFORE_TAILCALL_V4;
790 DeallocCall = BuildMI(MBB, MI, DL, TII.get(ROpc))
791 .addExternalSymbol(RestoreFn);
793 // The block has a return.
794 MachineBasicBlock::iterator It = MBB.getFirstTerminator();
795 assert(It->isReturn() && std::next(It) == MBB.end());
796 unsigned ROpc = Hexagon::RESTORE_DEALLOC_RET_JMP_V4;
797 DeallocCall = BuildMI(MBB, It, DL, TII.get(ROpc))
798 .addExternalSymbol(RestoreFn);
799 // Transfer the function live-out registers.
800 DeallocCall->copyImplicitOps(MF, It);
802 addCalleeSaveRegistersAsImpOperand(DeallocCall, MaxR, true);
806 for (unsigned i = 0; i < CSI.size(); ++i) {
807 unsigned Reg = CSI[i].getReg();
808 const TargetRegisterClass *RC = HRI.getMinimalPhysRegClass(Reg);
809 int FI = CSI[i].getFrameIdx();
810 TII.loadRegFromStackSlot(MBB, MI, Reg, FI, RC, &HRI);
816 void HexagonFrameLowering::eliminateCallFramePseudoInstr(MachineFunction &MF,
817 MachineBasicBlock &MBB, MachineBasicBlock::iterator I) const {
818 MachineInstr &MI = *I;
819 unsigned Opc = MI.getOpcode();
820 (void)Opc; // Silence compiler warning.
821 assert((Opc == Hexagon::ADJCALLSTACKDOWN || Opc == Hexagon::ADJCALLSTACKUP) &&
822 "Cannot handle this call frame pseudo instruction");
827 void HexagonFrameLowering::processFunctionBeforeFrameFinalized(
828 MachineFunction &MF, RegScavenger *RS) const {
829 // If this function has uses aligned stack and also has variable sized stack
830 // objects, then we need to map all spill slots to fixed positions, so that
831 // they can be accessed through FP. Otherwise they would have to be accessed
832 // via AP, which may not be available at the particular place in the program.
833 MachineFrameInfo *MFI = MF.getFrameInfo();
834 bool HasAlloca = MFI->hasVarSizedObjects();
835 bool HasAligna = (MFI->getMaxAlignment() > getStackAlignment());
837 if (!HasAlloca || !HasAligna)
840 unsigned LFS = MFI->getLocalFrameSize();
842 for (int i = 0, e = MFI->getObjectIndexEnd(); i != e; ++i) {
843 if (!MFI->isSpillSlotObjectIndex(i) || MFI->isDeadObjectIndex(i))
845 int S = MFI->getObjectSize(i);
848 MFI->mapLocalFrameObject(i, Offset);
851 MFI->setLocalFrameSize(LFS);
852 unsigned A = MFI->getLocalFrameMaxAlign();
853 assert(A <= 8 && "Unexpected local frame alignment");
855 MFI->setLocalFrameMaxAlign(8);
856 MFI->setUseLocalStackAllocationBlock(true);
859 /// Returns true if there is no caller saved registers available.
860 static bool needToReserveScavengingSpillSlots(MachineFunction &MF,
861 const HexagonRegisterInfo &HRI) {
862 MachineRegisterInfo &MRI = MF.getRegInfo();
863 const MCPhysReg *CallerSavedRegs = HRI.getCallerSavedRegs(&MF);
864 // Check for an unused caller-saved register.
865 for ( ; *CallerSavedRegs; ++CallerSavedRegs) {
866 MCPhysReg FreeReg = *CallerSavedRegs;
867 if (!MRI.reg_nodbg_empty(FreeReg))
870 // Check aliased register usage.
871 bool IsCurrentRegUsed = false;
872 for (MCRegAliasIterator AI(FreeReg, &HRI, false); AI.isValid(); ++AI)
873 if (!MRI.reg_nodbg_empty(*AI)) {
874 IsCurrentRegUsed = true;
877 if (IsCurrentRegUsed)
880 // Neither directly used nor used through an aliased register.
883 // All caller-saved registers are used.
888 /// Replaces the predicate spill code pseudo instructions by valid instructions.
889 bool HexagonFrameLowering::replacePredRegPseudoSpillCode(MachineFunction &MF)
891 auto &HST = static_cast<const HexagonSubtarget&>(MF.getSubtarget());
892 auto &HII = *HST.getInstrInfo();
893 MachineRegisterInfo &MRI = MF.getRegInfo();
894 bool HasReplacedPseudoInst = false;
895 // Replace predicate spill pseudo instructions by real code.
896 // Loop over all of the basic blocks.
897 for (MachineFunction::iterator MBBb = MF.begin(), MBBe = MF.end();
898 MBBb != MBBe; ++MBBb) {
899 MachineBasicBlock* MBB = MBBb;
900 // Traverse the basic block.
901 MachineBasicBlock::iterator NextII;
902 for (MachineBasicBlock::iterator MII = MBB->begin(); MII != MBB->end();
904 MachineInstr *MI = MII;
905 NextII = std::next(MII);
906 int Opc = MI->getOpcode();
907 if (Opc == Hexagon::STriw_pred) {
908 HasReplacedPseudoInst = true;
909 // STriw_pred FI, 0, SrcReg;
910 unsigned VirtReg = MRI.createVirtualRegister(&Hexagon::IntRegsRegClass);
911 unsigned SrcReg = MI->getOperand(2).getReg();
912 bool IsOrigSrcRegKilled = MI->getOperand(2).isKill();
914 assert(MI->getOperand(0).isFI() && "Expect a frame index");
915 assert(Hexagon::PredRegsRegClass.contains(SrcReg) &&
916 "Not a predicate register");
918 // Insert transfer to general purpose register.
919 // VirtReg = C2_tfrpr SrcPredReg
920 BuildMI(*MBB, MII, MI->getDebugLoc(), HII.get(Hexagon::C2_tfrpr),
921 VirtReg).addReg(SrcReg, getKillRegState(IsOrigSrcRegKilled));
923 // Change instruction to S2_storeri_io.
924 // S2_storeri_io FI, 0, VirtReg
925 MI->setDesc(HII.get(Hexagon::S2_storeri_io));
926 MI->getOperand(2).setReg(VirtReg);
927 MI->getOperand(2).setIsKill();
929 } else if (Opc == Hexagon::LDriw_pred) {
930 // DstReg = LDriw_pred FI, 0
931 MachineOperand &M0 = MI->getOperand(0);
937 unsigned VirtReg = MRI.createVirtualRegister(&Hexagon::IntRegsRegClass);
938 unsigned DestReg = MI->getOperand(0).getReg();
940 assert(MI->getOperand(1).isFI() && "Expect a frame index");
941 assert(Hexagon::PredRegsRegClass.contains(DestReg) &&
942 "Not a predicate register");
944 // Change instruction to L2_loadri_io.
945 // VirtReg = L2_loadri_io FI, 0
946 MI->setDesc(HII.get(Hexagon::L2_loadri_io));
947 MI->getOperand(0).setReg(VirtReg);
949 // Insert transfer to general purpose register.
950 // DestReg = C2_tfrrp VirtReg
951 const MCInstrDesc &D = HII.get(Hexagon::C2_tfrrp);
952 BuildMI(*MBB, std::next(MII), MI->getDebugLoc(), D, DestReg)
953 .addReg(VirtReg, getKillRegState(true));
954 HasReplacedPseudoInst = true;
958 return HasReplacedPseudoInst;
962 void HexagonFrameLowering::determineCalleeSaves(MachineFunction &MF,
963 BitVector &SavedRegs,
964 RegScavenger *RS) const {
965 TargetFrameLowering::determineCalleeSaves(MF, SavedRegs, RS);
967 auto &HST = static_cast<const HexagonSubtarget&>(MF.getSubtarget());
968 auto &HRI = *HST.getRegisterInfo();
970 bool HasEHReturn = MF.getInfo<HexagonMachineFunctionInfo>()->hasEHReturn();
972 // If we have a function containing __builtin_eh_return we want to spill and
973 // restore all callee saved registers. Pretend that they are used.
975 for (const MCPhysReg *CSRegs = HRI.getCalleeSavedRegs(&MF); *CSRegs;
977 SavedRegs.set(*CSRegs);
980 const TargetRegisterClass &RC = Hexagon::IntRegsRegClass;
982 // Replace predicate register pseudo spill code.
983 bool HasReplacedPseudoInst = replacePredRegPseudoSpillCode(MF);
985 // We need to reserve a a spill slot if scavenging could potentially require
986 // spilling a scavenged register.
987 if (HasReplacedPseudoInst && needToReserveScavengingSpillSlots(MF, HRI)) {
988 MachineFrameInfo *MFI = MF.getFrameInfo();
989 for (int i=0; i < NumberScavengerSlots; i++)
990 RS->addScavengingFrameIndex(
991 MFI->CreateSpillStackObject(RC.getSize(), RC.getAlignment()));
997 static void dump_registers(BitVector &Regs, const TargetRegisterInfo &TRI) {
999 for (int x = Regs.find_first(); x >= 0; x = Regs.find_next(x)) {
1001 dbgs() << ' ' << PrintReg(R, &TRI);
1008 bool HexagonFrameLowering::assignCalleeSavedSpillSlots(MachineFunction &MF,
1009 const TargetRegisterInfo *TRI, std::vector<CalleeSavedInfo> &CSI) const {
1010 DEBUG(dbgs() << LLVM_FUNCTION_NAME << " on "
1011 << MF.getFunction()->getName() << '\n');
1012 MachineFrameInfo *MFI = MF.getFrameInfo();
1013 BitVector SRegs(Hexagon::NUM_TARGET_REGS);
1015 // Generate a set of unique, callee-saved registers (SRegs), where each
1016 // register in the set is maximal in terms of sub-/super-register relation,
1017 // i.e. for each R in SRegs, no proper super-register of R is also in SRegs.
1019 // (1) For each callee-saved register, add that register and all of its
1020 // sub-registers to SRegs.
1021 DEBUG(dbgs() << "Initial CS registers: {");
1022 for (unsigned i = 0, n = CSI.size(); i < n; ++i) {
1023 unsigned R = CSI[i].getReg();
1024 DEBUG(dbgs() << ' ' << PrintReg(R, TRI));
1025 for (MCSubRegIterator SR(R, TRI, true); SR.isValid(); ++SR)
1028 DEBUG(dbgs() << " }\n");
1029 DEBUG(dbgs() << "SRegs.1: "; dump_registers(SRegs, *TRI); dbgs() << "\n");
1031 // (2) For each reserved register, remove that register and all of its
1032 // sub- and super-registers from SRegs.
1033 BitVector Reserved = TRI->getReservedRegs(MF);
1034 for (int x = Reserved.find_first(); x >= 0; x = Reserved.find_next(x)) {
1036 for (MCSuperRegIterator SR(R, TRI, true); SR.isValid(); ++SR)
1039 DEBUG(dbgs() << "Res: "; dump_registers(Reserved, *TRI); dbgs() << "\n");
1040 DEBUG(dbgs() << "SRegs.2: "; dump_registers(SRegs, *TRI); dbgs() << "\n");
1042 // (3) Collect all registers that have at least one sub-register in SRegs,
1043 // and also have no sub-registers that are reserved. These will be the can-
1044 // didates for saving as a whole instead of their individual sub-registers.
1045 // (Saving R17:16 instead of R16 is fine, but only if R17 was not reserved.)
1046 BitVector TmpSup(Hexagon::NUM_TARGET_REGS);
1047 for (int x = SRegs.find_first(); x >= 0; x = SRegs.find_next(x)) {
1049 for (MCSuperRegIterator SR(R, TRI); SR.isValid(); ++SR)
1052 for (int x = TmpSup.find_first(); x >= 0; x = TmpSup.find_next(x)) {
1054 for (MCSubRegIterator SR(R, TRI, true); SR.isValid(); ++SR) {
1061 DEBUG(dbgs() << "TmpSup: "; dump_registers(TmpSup, *TRI); dbgs() << "\n");
1063 // (4) Include all super-registers found in (3) into SRegs.
1065 DEBUG(dbgs() << "SRegs.4: "; dump_registers(SRegs, *TRI); dbgs() << "\n");
1067 // (5) For each register R in SRegs, if any super-register of R is in SRegs,
1068 // remove R from SRegs.
1069 for (int x = SRegs.find_first(); x >= 0; x = SRegs.find_next(x)) {
1071 for (MCSuperRegIterator SR(R, TRI); SR.isValid(); ++SR) {
1078 DEBUG(dbgs() << "SRegs.5: "; dump_registers(SRegs, *TRI); dbgs() << "\n");
1080 // Now, for each register that has a fixed stack slot, create the stack
1084 typedef TargetFrameLowering::SpillSlot SpillSlot;
1086 int MinOffset = 0; // CS offsets are negative.
1087 const SpillSlot *FixedSlots = getCalleeSavedSpillSlots(NumFixed);
1088 for (const SpillSlot *S = FixedSlots; S != FixedSlots+NumFixed; ++S) {
1091 const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(S->Reg);
1092 int FI = MFI->CreateFixedSpillStackObject(RC->getSize(), S->Offset);
1093 MinOffset = std::min(MinOffset, S->Offset);
1094 CSI.push_back(CalleeSavedInfo(S->Reg, FI));
1095 SRegs[S->Reg] = false;
1098 // There can be some registers that don't have fixed slots. For example,
1099 // we need to store R0-R3 in functions with exception handling. For each
1100 // such register, create a non-fixed stack object.
1101 for (int x = SRegs.find_first(); x >= 0; x = SRegs.find_next(x)) {
1103 const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(R);
1104 int Off = MinOffset - RC->getSize();
1105 unsigned Align = std::min(RC->getAlignment(), getStackAlignment());
1106 assert(isPowerOf2_32(Align));
1108 int FI = MFI->CreateFixedSpillStackObject(RC->getSize(), Off);
1109 MinOffset = std::min(MinOffset, Off);
1110 CSI.push_back(CalleeSavedInfo(R, FI));
1115 dbgs() << "CS information: {";
1116 for (unsigned i = 0, n = CSI.size(); i < n; ++i) {
1117 int FI = CSI[i].getFrameIdx();
1118 int Off = MFI->getObjectOffset(FI);
1119 dbgs() << ' ' << PrintReg(CSI[i].getReg(), TRI) << ":fi#" << FI << ":sp";
1128 // Verify that all registers were handled.
1129 bool MissedReg = false;
1130 for (int x = SRegs.find_first(); x >= 0; x = SRegs.find_next(x)) {
1132 dbgs() << PrintReg(R, TRI) << ' ';
1136 llvm_unreachable("...there are unhandled callee-saved registers!");
1143 void HexagonFrameLowering::expandAlloca(MachineInstr *AI,
1144 const HexagonInstrInfo &HII, unsigned SP, unsigned CF) const {
1145 MachineBasicBlock &MB = *AI->getParent();
1146 DebugLoc DL = AI->getDebugLoc();
1147 unsigned A = AI->getOperand(2).getImm();
1150 // Rd = alloca Rs, #A
1152 // If Rs and Rd are different registers, use this sequence:
1153 // Rd = sub(r29, Rs)
1154 // r29 = sub(r29, Rs)
1155 // Rd = and(Rd, #-A) ; if necessary
1156 // r29 = and(r29, #-A) ; if necessary
1157 // Rd = add(Rd, #CF) ; CF size aligned to at most A
1159 // Rd = sub(r29, Rs)
1160 // Rd = and(Rd, #-A) ; if necessary
1162 // Rd = add(Rd, #CF) ; CF size aligned to at most A
1164 MachineOperand &RdOp = AI->getOperand(0);
1165 MachineOperand &RsOp = AI->getOperand(1);
1166 unsigned Rd = RdOp.getReg(), Rs = RsOp.getReg();
1168 // Rd = sub(r29, Rs)
1169 BuildMI(MB, AI, DL, HII.get(Hexagon::A2_sub), Rd)
1173 // r29 = sub(r29, Rs)
1174 BuildMI(MB, AI, DL, HII.get(Hexagon::A2_sub), SP)
1179 // Rd = and(Rd, #-A)
1180 BuildMI(MB, AI, DL, HII.get(Hexagon::A2_andir), Rd)
1182 .addImm(-int64_t(A));
1184 BuildMI(MB, AI, DL, HII.get(Hexagon::A2_andir), SP)
1186 .addImm(-int64_t(A));
1190 BuildMI(MB, AI, DL, HII.get(TargetOpcode::COPY), SP)
1194 // Rd = add(Rd, #CF)
1195 BuildMI(MB, AI, DL, HII.get(Hexagon::A2_addi), Rd)
1202 bool HexagonFrameLowering::needsAligna(const MachineFunction &MF) const {
1203 const MachineFrameInfo *MFI = MF.getFrameInfo();
1204 if (!MFI->hasVarSizedObjects())
1206 unsigned MaxA = MFI->getMaxAlignment();
1207 if (MaxA <= getStackAlignment())
1213 MachineInstr *HexagonFrameLowering::getAlignaInstr(MachineFunction &MF) const {
1216 if (I.getOpcode() == Hexagon::ALIGNA)
1222 inline static bool isOptSize(const MachineFunction &MF) {
1223 AttributeSet AF = MF.getFunction()->getAttributes();
1224 return AF.hasAttribute(AttributeSet::FunctionIndex,
1225 Attribute::OptimizeForSize);
1228 inline static bool isMinSize(const MachineFunction &MF) {
1229 AttributeSet AF = MF.getFunction()->getAttributes();
1230 return AF.hasAttribute(AttributeSet::FunctionIndex, Attribute::MinSize);
1234 /// Determine whether the callee-saved register saves and restores should
1235 /// be generated via inline code. If this function returns "true", inline
1236 /// code will be generated. If this function returns "false", additional
1237 /// checks are performed, which may still lead to the inline code.
1238 bool HexagonFrameLowering::shouldInlineCSR(MachineFunction &MF,
1239 const CSIVect &CSI) const {
1240 if (MF.getInfo<HexagonMachineFunctionInfo>()->hasEHReturn())
1242 if (!isOptSize(MF) && !isMinSize(MF))
1243 if (MF.getTarget().getOptLevel() > CodeGenOpt::Default)
1246 // Check if CSI only has double registers, and if the registers form
1247 // a contiguous block starting from D8.
1248 BitVector Regs(Hexagon::NUM_TARGET_REGS);
1249 for (unsigned i = 0, n = CSI.size(); i < n; ++i) {
1250 unsigned R = CSI[i].getReg();
1251 if (!Hexagon::DoubleRegsRegClass.contains(R))
1255 int F = Regs.find_first();
1256 if (F != Hexagon::D8)
1259 int N = Regs.find_next(F);
1260 if (N >= 0 && N != F+1)
1269 bool HexagonFrameLowering::useSpillFunction(MachineFunction &MF,
1270 const CSIVect &CSI) const {
1271 if (shouldInlineCSR(MF, CSI))
1273 unsigned NumCSI = CSI.size();
1277 unsigned Threshold = isOptSize(MF) ? SpillFuncThresholdOs
1278 : SpillFuncThreshold;
1279 return Threshold < NumCSI;
1283 bool HexagonFrameLowering::useRestoreFunction(MachineFunction &MF,
1284 const CSIVect &CSI) const {
1285 if (shouldInlineCSR(MF, CSI))
1287 unsigned NumCSI = CSI.size();
1288 unsigned Threshold = isOptSize(MF) ? SpillFuncThresholdOs-1
1289 : SpillFuncThreshold;
1290 return Threshold < NumCSI;