xref: /freebsd/contrib/llvm-project/llvm/lib/Target/ARM/ARMCallLowering.cpp (revision 62987288060ff68c817b7056815aa9fb8ba8ecd7)
1 //===- llvm/lib/Target/ARM/ARMCallLowering.cpp - Call lowering ------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 /// \file
10 /// This file implements the lowering of LLVM calls to machine code calls for
11 /// GlobalISel.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "ARMCallLowering.h"
16 #include "ARMBaseInstrInfo.h"
17 #include "ARMISelLowering.h"
18 #include "ARMSubtarget.h"
19 #include "Utils/ARMBaseInfo.h"
20 #include "llvm/ADT/SmallVector.h"
21 #include "llvm/CodeGen/Analysis.h"
22 #include "llvm/CodeGen/CallingConvLower.h"
23 #include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
24 #include "llvm/CodeGen/GlobalISel/Utils.h"
25 #include "llvm/CodeGen/LowLevelTypeUtils.h"
26 #include "llvm/CodeGen/MachineBasicBlock.h"
27 #include "llvm/CodeGen/MachineFrameInfo.h"
28 #include "llvm/CodeGen/MachineFunction.h"
29 #include "llvm/CodeGen/MachineInstrBuilder.h"
30 #include "llvm/CodeGen/MachineMemOperand.h"
31 #include "llvm/CodeGen/MachineOperand.h"
32 #include "llvm/CodeGen/MachineRegisterInfo.h"
33 #include "llvm/CodeGen/TargetRegisterInfo.h"
34 #include "llvm/CodeGen/TargetSubtargetInfo.h"
35 #include "llvm/CodeGen/ValueTypes.h"
36 #include "llvm/CodeGenTypes/LowLevelType.h"
37 #include "llvm/CodeGenTypes/MachineValueType.h"
38 #include "llvm/IR/Attributes.h"
39 #include "llvm/IR/DataLayout.h"
40 #include "llvm/IR/DerivedTypes.h"
41 #include "llvm/IR/Function.h"
42 #include "llvm/IR/Type.h"
43 #include "llvm/IR/Value.h"
44 #include "llvm/Support/Casting.h"
45 #include <algorithm>
46 #include <cassert>
47 #include <cstdint>
48 #include <functional>
49 #include <utility>
50 
51 using namespace llvm;
52 
53 // Whether Big-endian GISel is enabled, defaults to off, can be enabled for
54 // testing.
55 static cl::opt<bool>
56     EnableGISelBigEndian("enable-arm-gisel-bigendian", cl::Hidden,
57                          cl::init(false),
58                          cl::desc("Enable Global-ISel Big Endian Lowering"));
59 
ARMCallLowering(const ARMTargetLowering & TLI)60 ARMCallLowering::ARMCallLowering(const ARMTargetLowering &TLI)
61     : CallLowering(&TLI) {}
62 
isSupportedType(const DataLayout & DL,const ARMTargetLowering & TLI,Type * T)63 static bool isSupportedType(const DataLayout &DL, const ARMTargetLowering &TLI,
64                             Type *T) {
65   if (T->isArrayTy())
66     return isSupportedType(DL, TLI, T->getArrayElementType());
67 
68   if (T->isStructTy()) {
69     // For now we only allow homogeneous structs that we can manipulate with
70     // G_MERGE_VALUES and G_UNMERGE_VALUES
71     auto StructT = cast<StructType>(T);
72     for (unsigned i = 1, e = StructT->getNumElements(); i != e; ++i)
73       if (StructT->getElementType(i) != StructT->getElementType(0))
74         return false;
75     return isSupportedType(DL, TLI, StructT->getElementType(0));
76   }
77 
78   EVT VT = TLI.getValueType(DL, T, true);
79   if (!VT.isSimple() || VT.isVector() ||
80       !(VT.isInteger() || VT.isFloatingPoint()))
81     return false;
82 
83   unsigned VTSize = VT.getSimpleVT().getSizeInBits();
84 
85   if (VTSize == 64)
86     // FIXME: Support i64 too
87     return VT.isFloatingPoint();
88 
89   return VTSize == 1 || VTSize == 8 || VTSize == 16 || VTSize == 32;
90 }
91 
92 namespace {
93 
94 /// Helper class for values going out through an ABI boundary (used for handling
95 /// function return values and call parameters).
96 struct ARMOutgoingValueHandler : public CallLowering::OutgoingValueHandler {
ARMOutgoingValueHandler__anon5229aa980111::ARMOutgoingValueHandler97   ARMOutgoingValueHandler(MachineIRBuilder &MIRBuilder,
98                           MachineRegisterInfo &MRI, MachineInstrBuilder &MIB)
99       : OutgoingValueHandler(MIRBuilder, MRI), MIB(MIB) {}
100 
getStackAddress__anon5229aa980111::ARMOutgoingValueHandler101   Register getStackAddress(uint64_t Size, int64_t Offset,
102                            MachinePointerInfo &MPO,
103                            ISD::ArgFlagsTy Flags) override {
104     assert((Size == 1 || Size == 2 || Size == 4 || Size == 8) &&
105            "Unsupported size");
106 
107     LLT p0 = LLT::pointer(0, 32);
108     LLT s32 = LLT::scalar(32);
109     auto SPReg = MIRBuilder.buildCopy(p0, Register(ARM::SP));
110 
111     auto OffsetReg = MIRBuilder.buildConstant(s32, Offset);
112 
113     auto AddrReg = MIRBuilder.buildPtrAdd(p0, SPReg, OffsetReg);
114 
115     MPO = MachinePointerInfo::getStack(MIRBuilder.getMF(), Offset);
116     return AddrReg.getReg(0);
117   }
118 
assignValueToReg__anon5229aa980111::ARMOutgoingValueHandler119   void assignValueToReg(Register ValVReg, Register PhysReg,
120                         const CCValAssign &VA) override {
121     assert(VA.isRegLoc() && "Value shouldn't be assigned to reg");
122     assert(VA.getLocReg() == PhysReg && "Assigning to the wrong reg?");
123 
124     assert(VA.getValVT().getSizeInBits() <= 64 && "Unsupported value size");
125     assert(VA.getLocVT().getSizeInBits() <= 64 && "Unsupported location size");
126 
127     Register ExtReg = extendRegister(ValVReg, VA);
128     MIRBuilder.buildCopy(PhysReg, ExtReg);
129     MIB.addUse(PhysReg, RegState::Implicit);
130   }
131 
assignValueToAddress__anon5229aa980111::ARMOutgoingValueHandler132   void assignValueToAddress(Register ValVReg, Register Addr, LLT MemTy,
133                             const MachinePointerInfo &MPO,
134                             const CCValAssign &VA) override {
135     Register ExtReg = extendRegister(ValVReg, VA);
136     auto MMO = MIRBuilder.getMF().getMachineMemOperand(
137         MPO, MachineMemOperand::MOStore, MemTy, Align(1));
138     MIRBuilder.buildStore(ExtReg, Addr, *MMO);
139   }
140 
assignCustomValue__anon5229aa980111::ARMOutgoingValueHandler141   unsigned assignCustomValue(CallLowering::ArgInfo &Arg,
142                              ArrayRef<CCValAssign> VAs,
143                              std::function<void()> *Thunk) override {
144     assert(Arg.Regs.size() == 1 && "Can't handle multple regs yet");
145 
146     const CCValAssign &VA = VAs[0];
147     assert(VA.needsCustom() && "Value doesn't need custom handling");
148 
149     // Custom lowering for other types, such as f16, is currently not supported
150     if (VA.getValVT() != MVT::f64)
151       return 0;
152 
153     const CCValAssign &NextVA = VAs[1];
154     assert(NextVA.needsCustom() && "Value doesn't need custom handling");
155     assert(NextVA.getValVT() == MVT::f64 && "Unsupported type");
156 
157     assert(VA.getValNo() == NextVA.getValNo() &&
158            "Values belong to different arguments");
159 
160     assert(VA.isRegLoc() && "Value should be in reg");
161     assert(NextVA.isRegLoc() && "Value should be in reg");
162 
163     Register NewRegs[] = {MRI.createGenericVirtualRegister(LLT::scalar(32)),
164                           MRI.createGenericVirtualRegister(LLT::scalar(32))};
165     MIRBuilder.buildUnmerge(NewRegs, Arg.Regs[0]);
166 
167     bool IsLittle = MIRBuilder.getMF().getSubtarget<ARMSubtarget>().isLittle();
168     if (!IsLittle)
169       std::swap(NewRegs[0], NewRegs[1]);
170 
171     if (Thunk) {
172       *Thunk = [=]() {
173         assignValueToReg(NewRegs[0], VA.getLocReg(), VA);
174         assignValueToReg(NewRegs[1], NextVA.getLocReg(), NextVA);
175       };
176       return 2;
177     }
178     assignValueToReg(NewRegs[0], VA.getLocReg(), VA);
179     assignValueToReg(NewRegs[1], NextVA.getLocReg(), NextVA);
180     return 2;
181   }
182 
183   MachineInstrBuilder MIB;
184 };
185 
186 } // end anonymous namespace
187 
188 /// Lower the return value for the already existing \p Ret. This assumes that
189 /// \p MIRBuilder's insertion point is correct.
lowerReturnVal(MachineIRBuilder & MIRBuilder,const Value * Val,ArrayRef<Register> VRegs,MachineInstrBuilder & Ret) const190 bool ARMCallLowering::lowerReturnVal(MachineIRBuilder &MIRBuilder,
191                                      const Value *Val, ArrayRef<Register> VRegs,
192                                      MachineInstrBuilder &Ret) const {
193   if (!Val)
194     // Nothing to do here.
195     return true;
196 
197   auto &MF = MIRBuilder.getMF();
198   const auto &F = MF.getFunction();
199 
200   const auto &DL = MF.getDataLayout();
201   auto &TLI = *getTLI<ARMTargetLowering>();
202   if (!isSupportedType(DL, TLI, Val->getType()))
203     return false;
204 
205   ArgInfo OrigRetInfo(VRegs, Val->getType(), 0);
206   setArgFlags(OrigRetInfo, AttributeList::ReturnIndex, DL, F);
207 
208   SmallVector<ArgInfo, 4> SplitRetInfos;
209   splitToValueTypes(OrigRetInfo, SplitRetInfos, DL, F.getCallingConv());
210 
211   CCAssignFn *AssignFn =
212       TLI.CCAssignFnForReturn(F.getCallingConv(), F.isVarArg());
213 
214   OutgoingValueAssigner RetAssigner(AssignFn);
215   ARMOutgoingValueHandler RetHandler(MIRBuilder, MF.getRegInfo(), Ret);
216   return determineAndHandleAssignments(RetHandler, RetAssigner, SplitRetInfos,
217                                        MIRBuilder, F.getCallingConv(),
218                                        F.isVarArg());
219 }
220 
lowerReturn(MachineIRBuilder & MIRBuilder,const Value * Val,ArrayRef<Register> VRegs,FunctionLoweringInfo & FLI) const221 bool ARMCallLowering::lowerReturn(MachineIRBuilder &MIRBuilder,
222                                   const Value *Val, ArrayRef<Register> VRegs,
223                                   FunctionLoweringInfo &FLI) const {
224   assert(!Val == VRegs.empty() && "Return value without a vreg");
225 
226   auto const &ST = MIRBuilder.getMF().getSubtarget<ARMSubtarget>();
227   unsigned Opcode = ST.getReturnOpcode();
228   auto Ret = MIRBuilder.buildInstrNoInsert(Opcode).add(predOps(ARMCC::AL));
229 
230   if (!lowerReturnVal(MIRBuilder, Val, VRegs, Ret))
231     return false;
232 
233   MIRBuilder.insertInstr(Ret);
234   return true;
235 }
236 
237 namespace {
238 
239 /// Helper class for values coming in through an ABI boundary (used for handling
240 /// formal arguments and call return values).
241 struct ARMIncomingValueHandler : public CallLowering::IncomingValueHandler {
ARMIncomingValueHandler__anon5229aa980311::ARMIncomingValueHandler242   ARMIncomingValueHandler(MachineIRBuilder &MIRBuilder,
243                           MachineRegisterInfo &MRI)
244       : IncomingValueHandler(MIRBuilder, MRI) {}
245 
getStackAddress__anon5229aa980311::ARMIncomingValueHandler246   Register getStackAddress(uint64_t Size, int64_t Offset,
247                            MachinePointerInfo &MPO,
248                            ISD::ArgFlagsTy Flags) override {
249     assert((Size == 1 || Size == 2 || Size == 4 || Size == 8) &&
250            "Unsupported size");
251 
252     auto &MFI = MIRBuilder.getMF().getFrameInfo();
253 
254     // Byval is assumed to be writable memory, but other stack passed arguments
255     // are not.
256     const bool IsImmutable = !Flags.isByVal();
257 
258     int FI = MFI.CreateFixedObject(Size, Offset, IsImmutable);
259     MPO = MachinePointerInfo::getFixedStack(MIRBuilder.getMF(), FI);
260 
261     return MIRBuilder.buildFrameIndex(LLT::pointer(MPO.getAddrSpace(), 32), FI)
262         .getReg(0);
263   }
264 
assignValueToAddress__anon5229aa980311::ARMIncomingValueHandler265   void assignValueToAddress(Register ValVReg, Register Addr, LLT MemTy,
266                             const MachinePointerInfo &MPO,
267                             const CCValAssign &VA) override {
268     if (VA.getLocInfo() == CCValAssign::SExt ||
269         VA.getLocInfo() == CCValAssign::ZExt) {
270       // If the value is zero- or sign-extended, its size becomes 4 bytes, so
271       // that's what we should load.
272       MemTy = LLT::scalar(32);
273       assert(MRI.getType(ValVReg).isScalar() && "Only scalars supported atm");
274 
275       auto LoadVReg = buildLoad(LLT::scalar(32), Addr, MemTy, MPO);
276       MIRBuilder.buildTrunc(ValVReg, LoadVReg);
277     } else {
278       // If the value is not extended, a simple load will suffice.
279       buildLoad(ValVReg, Addr, MemTy, MPO);
280     }
281   }
282 
buildLoad__anon5229aa980311::ARMIncomingValueHandler283   MachineInstrBuilder buildLoad(const DstOp &Res, Register Addr, LLT MemTy,
284                                 const MachinePointerInfo &MPO) {
285     MachineFunction &MF = MIRBuilder.getMF();
286 
287     auto MMO = MF.getMachineMemOperand(MPO, MachineMemOperand::MOLoad, MemTy,
288                                        inferAlignFromPtrInfo(MF, MPO));
289     return MIRBuilder.buildLoad(Res, Addr, *MMO);
290   }
291 
assignValueToReg__anon5229aa980311::ARMIncomingValueHandler292   void assignValueToReg(Register ValVReg, Register PhysReg,
293                         const CCValAssign &VA) override {
294     assert(VA.isRegLoc() && "Value shouldn't be assigned to reg");
295     assert(VA.getLocReg() == PhysReg && "Assigning to the wrong reg?");
296 
297     uint64_t ValSize = VA.getValVT().getFixedSizeInBits();
298     uint64_t LocSize = VA.getLocVT().getFixedSizeInBits();
299 
300     assert(ValSize <= 64 && "Unsupported value size");
301     assert(LocSize <= 64 && "Unsupported location size");
302 
303     markPhysRegUsed(PhysReg);
304     if (ValSize == LocSize) {
305       MIRBuilder.buildCopy(ValVReg, PhysReg);
306     } else {
307       assert(ValSize < LocSize && "Extensions not supported");
308 
309       // We cannot create a truncating copy, nor a trunc of a physical register.
310       // Therefore, we need to copy the content of the physical register into a
311       // virtual one and then truncate that.
312       auto PhysRegToVReg = MIRBuilder.buildCopy(LLT::scalar(LocSize), PhysReg);
313       MIRBuilder.buildTrunc(ValVReg, PhysRegToVReg);
314     }
315   }
316 
assignCustomValue__anon5229aa980311::ARMIncomingValueHandler317   unsigned assignCustomValue(ARMCallLowering::ArgInfo &Arg,
318                              ArrayRef<CCValAssign> VAs,
319                              std::function<void()> *Thunk) override {
320     assert(Arg.Regs.size() == 1 && "Can't handle multple regs yet");
321 
322     const CCValAssign &VA = VAs[0];
323     assert(VA.needsCustom() && "Value doesn't need custom handling");
324 
325     // Custom lowering for other types, such as f16, is currently not supported
326     if (VA.getValVT() != MVT::f64)
327       return 0;
328 
329     const CCValAssign &NextVA = VAs[1];
330     assert(NextVA.needsCustom() && "Value doesn't need custom handling");
331     assert(NextVA.getValVT() == MVT::f64 && "Unsupported type");
332 
333     assert(VA.getValNo() == NextVA.getValNo() &&
334            "Values belong to different arguments");
335 
336     assert(VA.isRegLoc() && "Value should be in reg");
337     assert(NextVA.isRegLoc() && "Value should be in reg");
338 
339     Register NewRegs[] = {MRI.createGenericVirtualRegister(LLT::scalar(32)),
340                           MRI.createGenericVirtualRegister(LLT::scalar(32))};
341 
342     assignValueToReg(NewRegs[0], VA.getLocReg(), VA);
343     assignValueToReg(NewRegs[1], NextVA.getLocReg(), NextVA);
344 
345     bool IsLittle = MIRBuilder.getMF().getSubtarget<ARMSubtarget>().isLittle();
346     if (!IsLittle)
347       std::swap(NewRegs[0], NewRegs[1]);
348 
349     MIRBuilder.buildMergeLikeInstr(Arg.Regs[0], NewRegs);
350 
351     return 2;
352   }
353 
354   /// Marking a physical register as used is different between formal
355   /// parameters, where it's a basic block live-in, and call returns, where it's
356   /// an implicit-def of the call instruction.
357   virtual void markPhysRegUsed(unsigned PhysReg) = 0;
358 };
359 
360 struct FormalArgHandler : public ARMIncomingValueHandler {
FormalArgHandler__anon5229aa980311::FormalArgHandler361   FormalArgHandler(MachineIRBuilder &MIRBuilder, MachineRegisterInfo &MRI)
362       : ARMIncomingValueHandler(MIRBuilder, MRI) {}
363 
markPhysRegUsed__anon5229aa980311::FormalArgHandler364   void markPhysRegUsed(unsigned PhysReg) override {
365     MIRBuilder.getMRI()->addLiveIn(PhysReg);
366     MIRBuilder.getMBB().addLiveIn(PhysReg);
367   }
368 };
369 
370 } // end anonymous namespace
371 
lowerFormalArguments(MachineIRBuilder & MIRBuilder,const Function & F,ArrayRef<ArrayRef<Register>> VRegs,FunctionLoweringInfo & FLI) const372 bool ARMCallLowering::lowerFormalArguments(MachineIRBuilder &MIRBuilder,
373                                            const Function &F,
374                                            ArrayRef<ArrayRef<Register>> VRegs,
375                                            FunctionLoweringInfo &FLI) const {
376   auto &TLI = *getTLI<ARMTargetLowering>();
377   auto Subtarget = TLI.getSubtarget();
378 
379   if (Subtarget->isThumb1Only())
380     return false;
381 
382   // Quick exit if there aren't any args
383   if (F.arg_empty())
384     return true;
385 
386   if (F.isVarArg())
387     return false;
388 
389   auto &MF = MIRBuilder.getMF();
390   auto &MBB = MIRBuilder.getMBB();
391   const auto &DL = MF.getDataLayout();
392 
393   for (auto &Arg : F.args()) {
394     if (!isSupportedType(DL, TLI, Arg.getType()))
395       return false;
396     if (Arg.hasPassPointeeByValueCopyAttr())
397       return false;
398   }
399 
400   CCAssignFn *AssignFn =
401       TLI.CCAssignFnForCall(F.getCallingConv(), F.isVarArg());
402 
403   OutgoingValueAssigner ArgAssigner(AssignFn);
404   FormalArgHandler ArgHandler(MIRBuilder, MIRBuilder.getMF().getRegInfo());
405 
406   SmallVector<ArgInfo, 8> SplitArgInfos;
407   unsigned Idx = 0;
408   for (auto &Arg : F.args()) {
409     ArgInfo OrigArgInfo(VRegs[Idx], Arg.getType(), Idx);
410 
411     setArgFlags(OrigArgInfo, Idx + AttributeList::FirstArgIndex, DL, F);
412     splitToValueTypes(OrigArgInfo, SplitArgInfos, DL, F.getCallingConv());
413 
414     Idx++;
415   }
416 
417   if (!MBB.empty())
418     MIRBuilder.setInstr(*MBB.begin());
419 
420   if (!determineAndHandleAssignments(ArgHandler, ArgAssigner, SplitArgInfos,
421                                      MIRBuilder, F.getCallingConv(),
422                                      F.isVarArg()))
423     return false;
424 
425   // Move back to the end of the basic block.
426   MIRBuilder.setMBB(MBB);
427   return true;
428 }
429 
430 namespace {
431 
432 struct CallReturnHandler : public ARMIncomingValueHandler {
CallReturnHandler__anon5229aa980411::CallReturnHandler433   CallReturnHandler(MachineIRBuilder &MIRBuilder, MachineRegisterInfo &MRI,
434                     MachineInstrBuilder MIB)
435       : ARMIncomingValueHandler(MIRBuilder, MRI), MIB(MIB) {}
436 
markPhysRegUsed__anon5229aa980411::CallReturnHandler437   void markPhysRegUsed(unsigned PhysReg) override {
438     MIB.addDef(PhysReg, RegState::Implicit);
439   }
440 
441   MachineInstrBuilder MIB;
442 };
443 
444 // FIXME: This should move to the ARMSubtarget when it supports all the opcodes.
getCallOpcode(const MachineFunction & MF,const ARMSubtarget & STI,bool isDirect)445 unsigned getCallOpcode(const MachineFunction &MF, const ARMSubtarget &STI,
446                        bool isDirect) {
447   if (isDirect)
448     return STI.isThumb() ? ARM::tBL : ARM::BL;
449 
450   if (STI.isThumb())
451     return gettBLXrOpcode(MF);
452 
453   if (STI.hasV5TOps())
454     return getBLXOpcode(MF);
455 
456   if (STI.hasV4TOps())
457     return ARM::BX_CALL;
458 
459   return ARM::BMOVPCRX_CALL;
460 }
461 } // end anonymous namespace
462 
lowerCall(MachineIRBuilder & MIRBuilder,CallLoweringInfo & Info) const463 bool ARMCallLowering::lowerCall(MachineIRBuilder &MIRBuilder, CallLoweringInfo &Info) const {
464   MachineFunction &MF = MIRBuilder.getMF();
465   const auto &TLI = *getTLI<ARMTargetLowering>();
466   const auto &DL = MF.getDataLayout();
467   const auto &STI = MF.getSubtarget<ARMSubtarget>();
468   const TargetRegisterInfo *TRI = STI.getRegisterInfo();
469   MachineRegisterInfo &MRI = MF.getRegInfo();
470 
471   if (STI.genLongCalls())
472     return false;
473 
474   if (STI.isThumb1Only())
475     return false;
476 
477   auto CallSeqStart = MIRBuilder.buildInstr(ARM::ADJCALLSTACKDOWN);
478 
479   // Create the call instruction so we can add the implicit uses of arg
480   // registers, but don't insert it yet.
481   bool IsDirect = !Info.Callee.isReg();
482   auto CallOpcode = getCallOpcode(MF, STI, IsDirect);
483   auto MIB = MIRBuilder.buildInstrNoInsert(CallOpcode);
484 
485   bool IsThumb = STI.isThumb();
486   if (IsThumb)
487     MIB.add(predOps(ARMCC::AL));
488 
489   MIB.add(Info.Callee);
490   if (!IsDirect) {
491     auto CalleeReg = Info.Callee.getReg();
492     if (CalleeReg && !CalleeReg.isPhysical()) {
493       unsigned CalleeIdx = IsThumb ? 2 : 0;
494       MIB->getOperand(CalleeIdx).setReg(constrainOperandRegClass(
495           MF, *TRI, MRI, *STI.getInstrInfo(), *STI.getRegBankInfo(),
496           *MIB.getInstr(), MIB->getDesc(), Info.Callee, CalleeIdx));
497     }
498   }
499 
500   MIB.addRegMask(TRI->getCallPreservedMask(MF, Info.CallConv));
501 
502   SmallVector<ArgInfo, 8> ArgInfos;
503   for (auto Arg : Info.OrigArgs) {
504     if (!isSupportedType(DL, TLI, Arg.Ty))
505       return false;
506 
507     if (Arg.Flags[0].isByVal())
508       return false;
509 
510     splitToValueTypes(Arg, ArgInfos, DL, Info.CallConv);
511   }
512 
513   auto ArgAssignFn = TLI.CCAssignFnForCall(Info.CallConv, Info.IsVarArg);
514   OutgoingValueAssigner ArgAssigner(ArgAssignFn);
515   ARMOutgoingValueHandler ArgHandler(MIRBuilder, MRI, MIB);
516   if (!determineAndHandleAssignments(ArgHandler, ArgAssigner, ArgInfos,
517                                      MIRBuilder, Info.CallConv, Info.IsVarArg))
518     return false;
519 
520   // Now we can add the actual call instruction to the correct basic block.
521   MIRBuilder.insertInstr(MIB);
522 
523   if (!Info.OrigRet.Ty->isVoidTy()) {
524     if (!isSupportedType(DL, TLI, Info.OrigRet.Ty))
525       return false;
526 
527     ArgInfos.clear();
528     splitToValueTypes(Info.OrigRet, ArgInfos, DL, Info.CallConv);
529     auto RetAssignFn = TLI.CCAssignFnForReturn(Info.CallConv, Info.IsVarArg);
530     OutgoingValueAssigner Assigner(RetAssignFn);
531     CallReturnHandler RetHandler(MIRBuilder, MRI, MIB);
532     if (!determineAndHandleAssignments(RetHandler, Assigner, ArgInfos,
533                                        MIRBuilder, Info.CallConv,
534                                        Info.IsVarArg))
535       return false;
536   }
537 
538   // We now know the size of the stack - update the ADJCALLSTACKDOWN
539   // accordingly.
540   CallSeqStart.addImm(ArgAssigner.StackSize).addImm(0).add(predOps(ARMCC::AL));
541 
542   MIRBuilder.buildInstr(ARM::ADJCALLSTACKUP)
543       .addImm(ArgAssigner.StackSize)
544       .addImm(-1ULL)
545       .add(predOps(ARMCC::AL));
546 
547   return true;
548 }
549 
enableBigEndian() const550 bool ARMCallLowering::enableBigEndian() const { return EnableGISelBigEndian; }