1 //===-- ARMFastISel.cpp - ARM FastISel implementation ---------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the ARM-specific support for the FastISel class. Some
11 // of the target-specific code is generated by tablegen in the file
12 // ARMGenFastISel.inc, which is #included here.
14 //===----------------------------------------------------------------------===//
17 #include "ARMBaseInstrInfo.h"
18 #include "ARMRegisterInfo.h"
19 #include "ARMTargetMachine.h"
20 #include "ARMSubtarget.h"
21 #include "llvm/CallingConv.h"
22 #include "llvm/DerivedTypes.h"
23 #include "llvm/GlobalVariable.h"
24 #include "llvm/Instructions.h"
25 #include "llvm/IntrinsicInst.h"
26 #include "llvm/CodeGen/Analysis.h"
27 #include "llvm/CodeGen/FastISel.h"
28 #include "llvm/CodeGen/FunctionLoweringInfo.h"
29 #include "llvm/CodeGen/MachineInstrBuilder.h"
30 #include "llvm/CodeGen/MachineModuleInfo.h"
31 #include "llvm/CodeGen/MachineConstantPool.h"
32 #include "llvm/CodeGen/MachineFrameInfo.h"
33 #include "llvm/CodeGen/MachineRegisterInfo.h"
34 #include "llvm/Support/CallSite.h"
35 #include "llvm/Support/CommandLine.h"
36 #include "llvm/Support/ErrorHandling.h"
37 #include "llvm/Support/GetElementPtrTypeIterator.h"
38 #include "llvm/Target/TargetData.h"
39 #include "llvm/Target/TargetInstrInfo.h"
40 #include "llvm/Target/TargetLowering.h"
41 #include "llvm/Target/TargetMachine.h"
42 #include "llvm/Target/TargetOptions.h"
46 EnableARMFastISel("arm-fast-isel",
47 cl::desc("Turn on experimental ARM fast-isel support"),
48 cl::init(false), cl::Hidden);
52 class ARMFastISel : public FastISel {
54 /// Subtarget - Keep a pointer to the ARMSubtarget around so that we can
55 /// make the right decision when generating code for different targets.
56 const ARMSubtarget *Subtarget;
57 const TargetMachine &TM;
58 const TargetInstrInfo &TII;
59 const TargetLowering &TLI;
60 const ARMFunctionInfo *AFI;
62 // Convenience variable to avoid checking all the time.
66 explicit ARMFastISel(FunctionLoweringInfo &funcInfo)
68 TM(funcInfo.MF->getTarget()),
69 TII(*TM.getInstrInfo()),
70 TLI(*TM.getTargetLowering()) {
71 Subtarget = &TM.getSubtarget<ARMSubtarget>();
72 AFI = funcInfo.MF->getInfo<ARMFunctionInfo>();
73 isThumb = AFI->isThumbFunction();
76 // Code from FastISel.cpp.
77 virtual unsigned FastEmitInst_(unsigned MachineInstOpcode,
78 const TargetRegisterClass *RC);
79 virtual unsigned FastEmitInst_r(unsigned MachineInstOpcode,
80 const TargetRegisterClass *RC,
81 unsigned Op0, bool Op0IsKill);
82 virtual unsigned FastEmitInst_rr(unsigned MachineInstOpcode,
83 const TargetRegisterClass *RC,
84 unsigned Op0, bool Op0IsKill,
85 unsigned Op1, bool Op1IsKill);
86 virtual unsigned FastEmitInst_ri(unsigned MachineInstOpcode,
87 const TargetRegisterClass *RC,
88 unsigned Op0, bool Op0IsKill,
90 virtual unsigned FastEmitInst_rf(unsigned MachineInstOpcode,
91 const TargetRegisterClass *RC,
92 unsigned Op0, bool Op0IsKill,
93 const ConstantFP *FPImm);
94 virtual unsigned FastEmitInst_i(unsigned MachineInstOpcode,
95 const TargetRegisterClass *RC,
97 virtual unsigned FastEmitInst_rri(unsigned MachineInstOpcode,
98 const TargetRegisterClass *RC,
99 unsigned Op0, bool Op0IsKill,
100 unsigned Op1, bool Op1IsKill,
102 virtual unsigned FastEmitInst_extractsubreg(MVT RetVT,
103 unsigned Op0, bool Op0IsKill,
106 // Backend specific FastISel code.
107 virtual bool TargetSelectInstruction(const Instruction *I);
108 virtual unsigned TargetMaterializeConstant(const Constant *C);
110 #include "ARMGenFastISel.inc"
112 // Instruction selection routines.
113 virtual bool ARMSelectLoad(const Instruction *I);
114 virtual bool ARMSelectStore(const Instruction *I);
118 bool isTypeLegal(const Type *Ty, EVT &VT);
119 bool isLoadTypeLegal(const Type *Ty, EVT &VT);
120 bool ARMEmitLoad(EVT VT, unsigned &ResultReg, unsigned Reg, int Offset);
121 bool ARMEmitStore(EVT VT, unsigned SrcReg, unsigned Reg, int Offset);
122 bool ARMLoadAlloca(const Instruction *I);
123 bool ARMStoreAlloca(const Instruction *I, unsigned SrcReg);
124 bool ARMComputeRegOffset(const Value *Obj, unsigned &Reg, int &Offset);
125 bool ARMMaterializeConstant(const ConstantInt *Val, unsigned &Reg);
127 bool DefinesOptionalPredicate(MachineInstr *MI, bool *CPSR);
128 const MachineInstrBuilder &AddOptionalDefs(const MachineInstrBuilder &MIB);
131 } // end anonymous namespace
133 // #include "ARMGenCallingConv.inc"
135 // DefinesOptionalPredicate - This is different from DefinesPredicate in that
136 // we don't care about implicit defs here, just places we'll need to add a
137 // default CCReg argument. Sets CPSR if we're setting CPSR instead of CCR.
138 bool ARMFastISel::DefinesOptionalPredicate(MachineInstr *MI, bool *CPSR) {
139 const TargetInstrDesc &TID = MI->getDesc();
140 if (!TID.hasOptionalDef())
143 // Look to see if our OptionalDef is defining CPSR or CCR.
144 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
145 const MachineOperand &MO = MI->getOperand(i);
146 if (!MO.isReg() || !MO.isDef()) continue;
147 if (MO.getReg() == ARM::CPSR)
153 // If the machine is predicable go ahead and add the predicate operands, if
154 // it needs default CC operands add those.
155 const MachineInstrBuilder &
156 ARMFastISel::AddOptionalDefs(const MachineInstrBuilder &MIB) {
157 MachineInstr *MI = &*MIB;
159 // Do we use a predicate?
160 if (TII.isPredicable(MI))
163 // Do we optionally set a predicate? Preds is size > 0 iff the predicate
164 // defines CPSR. All other OptionalDefines in ARM are the CCR register.
166 if (DefinesOptionalPredicate(MI, &CPSR)) {
175 unsigned ARMFastISel::FastEmitInst_(unsigned MachineInstOpcode,
176 const TargetRegisterClass* RC) {
177 unsigned ResultReg = createResultReg(RC);
178 const TargetInstrDesc &II = TII.get(MachineInstOpcode);
180 AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II, ResultReg));
184 unsigned ARMFastISel::FastEmitInst_r(unsigned MachineInstOpcode,
185 const TargetRegisterClass *RC,
186 unsigned Op0, bool Op0IsKill) {
187 unsigned ResultReg = createResultReg(RC);
188 const TargetInstrDesc &II = TII.get(MachineInstOpcode);
190 if (II.getNumDefs() >= 1)
191 AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II, ResultReg)
192 .addReg(Op0, Op0IsKill * RegState::Kill));
194 AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II)
195 .addReg(Op0, Op0IsKill * RegState::Kill));
196 AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
197 TII.get(TargetOpcode::COPY), ResultReg)
198 .addReg(II.ImplicitDefs[0]));
203 unsigned ARMFastISel::FastEmitInst_rr(unsigned MachineInstOpcode,
204 const TargetRegisterClass *RC,
205 unsigned Op0, bool Op0IsKill,
206 unsigned Op1, bool Op1IsKill) {
207 unsigned ResultReg = createResultReg(RC);
208 const TargetInstrDesc &II = TII.get(MachineInstOpcode);
210 if (II.getNumDefs() >= 1)
211 AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II, ResultReg)
212 .addReg(Op0, Op0IsKill * RegState::Kill)
213 .addReg(Op1, Op1IsKill * RegState::Kill));
215 AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II)
216 .addReg(Op0, Op0IsKill * RegState::Kill)
217 .addReg(Op1, Op1IsKill * RegState::Kill));
218 AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
219 TII.get(TargetOpcode::COPY), ResultReg)
220 .addReg(II.ImplicitDefs[0]));
225 unsigned ARMFastISel::FastEmitInst_ri(unsigned MachineInstOpcode,
226 const TargetRegisterClass *RC,
227 unsigned Op0, bool Op0IsKill,
229 unsigned ResultReg = createResultReg(RC);
230 const TargetInstrDesc &II = TII.get(MachineInstOpcode);
232 if (II.getNumDefs() >= 1)
233 AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II, ResultReg)
234 .addReg(Op0, Op0IsKill * RegState::Kill)
237 AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II)
238 .addReg(Op0, Op0IsKill * RegState::Kill)
240 AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
241 TII.get(TargetOpcode::COPY), ResultReg)
242 .addReg(II.ImplicitDefs[0]));
247 unsigned ARMFastISel::FastEmitInst_rf(unsigned MachineInstOpcode,
248 const TargetRegisterClass *RC,
249 unsigned Op0, bool Op0IsKill,
250 const ConstantFP *FPImm) {
251 unsigned ResultReg = createResultReg(RC);
252 const TargetInstrDesc &II = TII.get(MachineInstOpcode);
254 if (II.getNumDefs() >= 1)
255 AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II, ResultReg)
256 .addReg(Op0, Op0IsKill * RegState::Kill)
259 AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II)
260 .addReg(Op0, Op0IsKill * RegState::Kill)
262 AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
263 TII.get(TargetOpcode::COPY), ResultReg)
264 .addReg(II.ImplicitDefs[0]));
269 unsigned ARMFastISel::FastEmitInst_rri(unsigned MachineInstOpcode,
270 const TargetRegisterClass *RC,
271 unsigned Op0, bool Op0IsKill,
272 unsigned Op1, bool Op1IsKill,
274 unsigned ResultReg = createResultReg(RC);
275 const TargetInstrDesc &II = TII.get(MachineInstOpcode);
277 if (II.getNumDefs() >= 1)
278 AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II, ResultReg)
279 .addReg(Op0, Op0IsKill * RegState::Kill)
280 .addReg(Op1, Op1IsKill * RegState::Kill)
283 AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II)
284 .addReg(Op0, Op0IsKill * RegState::Kill)
285 .addReg(Op1, Op1IsKill * RegState::Kill)
287 AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
288 TII.get(TargetOpcode::COPY), ResultReg)
289 .addReg(II.ImplicitDefs[0]));
294 unsigned ARMFastISel::FastEmitInst_i(unsigned MachineInstOpcode,
295 const TargetRegisterClass *RC,
297 unsigned ResultReg = createResultReg(RC);
298 const TargetInstrDesc &II = TII.get(MachineInstOpcode);
300 if (II.getNumDefs() >= 1)
301 AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II, ResultReg)
304 AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, II)
306 AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
307 TII.get(TargetOpcode::COPY), ResultReg)
308 .addReg(II.ImplicitDefs[0]));
313 unsigned ARMFastISel::FastEmitInst_extractsubreg(MVT RetVT,
314 unsigned Op0, bool Op0IsKill,
316 unsigned ResultReg = createResultReg(TLI.getRegClassFor(RetVT));
317 assert(TargetRegisterInfo::isVirtualRegister(Op0) &&
318 "Cannot yet extract from physregs");
319 AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt,
320 DL, TII.get(TargetOpcode::COPY), ResultReg)
321 .addReg(Op0, getKillRegState(Op0IsKill), Idx));
325 unsigned ARMFastISel::TargetMaterializeConstant(const Constant *C) {
326 EVT VT = TLI.getValueType(C->getType(), true);
328 // Only handle simple types.
329 if (!VT.isSimple()) return 0;
331 // TODO: This should be safe for fp because they're just bits from the
333 // TODO: Theoretically we could materialize fp constants with instructions
336 // MachineConstantPool wants an explicit alignment.
337 unsigned Align = TD.getPrefTypeAlignment(C->getType());
339 // TODO: Figure out if this is correct.
340 Align = TD.getTypeAllocSize(C->getType());
342 unsigned Idx = MCP.getConstantPoolIndex(C, Align);
344 unsigned DestReg = createResultReg(TLI.getRegClassFor(VT));
345 // Different addressing modes between ARM/Thumb2 for constant pool loads.
347 AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
348 TII.get(ARM::t2LDRpci))
349 .addReg(DestReg).addConstantPoolIndex(Idx));
351 AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
353 .addReg(DestReg).addConstantPoolIndex(Idx)
354 .addReg(0).addImm(0));
359 bool ARMFastISel::isTypeLegal(const Type *Ty, EVT &VT) {
360 VT = TLI.getValueType(Ty, true);
362 // Only handle simple types.
363 if (VT == MVT::Other || !VT.isSimple()) return false;
365 // Handle all legal types, i.e. a register that will directly hold this
367 return TLI.isTypeLegal(VT);
370 bool ARMFastISel::isLoadTypeLegal(const Type *Ty, EVT &VT) {
371 if (isTypeLegal(Ty, VT)) return true;
373 // If this is a type than can be sign or zero-extended to a basic operation
374 // go ahead and accept it now.
375 if (VT == MVT::i8 || VT == MVT::i16)
381 // Computes the Reg+Offset to get to an object.
382 bool ARMFastISel::ARMComputeRegOffset(const Value *Obj, unsigned &Reg,
384 // Some boilerplate from the X86 FastISel.
385 const User *U = NULL;
386 unsigned Opcode = Instruction::UserOp1;
387 if (const Instruction *I = dyn_cast<Instruction>(Obj)) {
388 // Don't walk into other basic blocks; it's possible we haven't
389 // visited them yet, so the instructions may not yet be assigned
390 // virtual registers.
391 if (FuncInfo.MBBMap[I->getParent()] != FuncInfo.MBB)
394 Opcode = I->getOpcode();
396 } else if (const ConstantExpr *C = dyn_cast<ConstantExpr>(Obj)) {
397 Opcode = C->getOpcode();
401 if (const PointerType *Ty = dyn_cast<PointerType>(Obj->getType()))
402 if (Ty->getAddressSpace() > 255)
403 // Fast instruction selection doesn't support the special
409 //errs() << "Failing Opcode is: " << *Op1 << "\n";
411 case Instruction::Alloca: {
412 assert(false && "Alloca should have been handled earlier!");
417 if (const GlobalValue *GV = dyn_cast<GlobalValue>(Obj)) {
418 //errs() << "Failing GV is: " << GV << "\n";
423 // Try to get this in a register if nothing else has worked.
424 Reg = getRegForValue(Obj);
425 if (Reg == 0) return false;
427 // Since the offset may be too large for the load instruction
428 // get the reg+offset into a register.
429 // TODO: Verify the additions work, otherwise we'll need to add the
430 // offset instead of 0 to the instructions and do all sorts of operand
432 // TODO: Optimize this somewhat.
434 ARMCC::CondCodes Pred = ARMCC::AL;
435 unsigned PredReg = 0;
438 emitARMRegPlusImmediate(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
439 Reg, Reg, Offset, Pred, PredReg,
440 static_cast<const ARMBaseInstrInfo&>(TII));
442 assert(AFI->isThumb2Function());
443 emitT2RegPlusImmediate(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
444 Reg, Reg, Offset, Pred, PredReg,
445 static_cast<const ARMBaseInstrInfo&>(TII));
452 bool ARMFastISel::ARMLoadAlloca(const Instruction *I) {
453 Value *Op0 = I->getOperand(0);
455 // Verify it's an alloca.
456 if (const AllocaInst *AI = dyn_cast<AllocaInst>(Op0)) {
457 DenseMap<const AllocaInst*, int>::iterator SI =
458 FuncInfo.StaticAllocaMap.find(AI);
460 if (SI != FuncInfo.StaticAllocaMap.end()) {
461 TargetRegisterClass* RC = TLI.getRegClassFor(TLI.getPointerTy());
462 unsigned ResultReg = createResultReg(RC);
463 TII.loadRegFromStackSlot(*FuncInfo.MBB, *FuncInfo.InsertPt,
464 ResultReg, SI->second, RC,
465 TM.getRegisterInfo());
466 UpdateValueMap(I, ResultReg);
473 bool ARMFastISel::ARMEmitLoad(EVT VT, unsigned &ResultReg,
474 unsigned Reg, int Offset) {
476 assert(VT.isSimple() && "Non-simple types are invalid here!");
479 switch (VT.getSimpleVT().SimpleTy) {
481 assert(false && "Trying to emit for an unhandled type!");
484 Opc = isThumb ? ARM::tLDRH : ARM::LDRH;
488 Opc = isThumb ? ARM::tLDRB : ARM::LDRB;
492 Opc = isThumb ? ARM::tLDR : ARM::LDR;
496 ResultReg = createResultReg(TLI.getRegClassFor(VT));
498 // TODO: Fix the Addressing modes so that these can share some code.
499 // Since this is a Thumb1 load this will work in Thumb1 or 2 mode.
501 AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
502 TII.get(Opc), ResultReg)
503 .addReg(Reg).addImm(Offset).addReg(0));
505 AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
506 TII.get(Opc), ResultReg)
507 .addReg(Reg).addReg(0).addImm(Offset));
512 bool ARMFastISel::ARMStoreAlloca(const Instruction *I, unsigned SrcReg) {
513 Value *Op1 = I->getOperand(1);
515 // Verify it's an alloca.
516 if (const AllocaInst *AI = dyn_cast<AllocaInst>(Op1)) {
517 DenseMap<const AllocaInst*, int>::iterator SI =
518 FuncInfo.StaticAllocaMap.find(AI);
520 if (SI != FuncInfo.StaticAllocaMap.end()) {
521 TargetRegisterClass* RC = TLI.getRegClassFor(TLI.getPointerTy());
522 assert(SrcReg != 0 && "Nothing to store!");
523 TII.storeRegToStackSlot(*FuncInfo.MBB, *FuncInfo.InsertPt,
524 SrcReg, true /*isKill*/, SI->second, RC,
525 TM.getRegisterInfo());
532 bool ARMFastISel::ARMEmitStore(EVT VT, unsigned SrcReg,
533 unsigned DstReg, int Offset) {
535 switch (VT.getSimpleVT().SimpleTy) {
536 default: return false;
538 case MVT::i8: StrOpc = isThumb ? ARM::tSTRB : ARM::STRB; break;
539 case MVT::i16: StrOpc = isThumb ? ARM::tSTRH : ARM::STRH; break;
540 case MVT::i32: StrOpc = isThumb ? ARM::tSTR : ARM::STR; break;
542 if (!Subtarget->hasVFP2()) return false;
546 if (!Subtarget->hasVFP2()) return false;
552 AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
553 TII.get(StrOpc), SrcReg)
554 .addReg(DstReg).addImm(Offset).addReg(0));
556 AddOptionalDefs(BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL,
557 TII.get(StrOpc), SrcReg)
558 .addReg(DstReg).addReg(0).addImm(Offset));
563 bool ARMFastISel::ARMSelectStore(const Instruction *I) {
564 Value *Op0 = I->getOperand(0);
567 // Yay type legalization
569 if (!isLoadTypeLegal(I->getOperand(0)->getType(), VT))
572 // Get the value to be stored into a register.
573 SrcReg = getRegForValue(Op0);
577 // If we're an alloca we know we have a frame index and can emit the store
579 if (ARMStoreAlloca(I, SrcReg))
582 // Our register and offset with innocuous defaults.
586 // See if we can handle this as Reg + Offset
587 if (!ARMComputeRegOffset(I->getOperand(1), Reg, Offset))
590 if (!ARMEmitStore(VT, SrcReg, Reg, Offset /* 0 */)) return false;
596 bool ARMFastISel::ARMSelectLoad(const Instruction *I) {
597 // If we're an alloca we know we have a frame index and can emit the load
598 // directly in short order.
599 if (ARMLoadAlloca(I))
602 // Verify we have a legal type before going any further.
604 if (!isLoadTypeLegal(I->getType(), VT))
607 // Our register and offset with innocuous defaults.
611 // See if we can handle this as Reg + Offset
612 if (!ARMComputeRegOffset(I->getOperand(0), Reg, Offset))
616 if (!ARMEmitLoad(VT, ResultReg, Reg, Offset /* 0 */)) return false;
618 UpdateValueMap(I, ResultReg);
622 // TODO: SoftFP support.
623 bool ARMFastISel::TargetSelectInstruction(const Instruction *I) {
624 // No Thumb-1 for now.
625 if (isThumb && !AFI->isThumb2Function()) return false;
627 switch (I->getOpcode()) {
628 case Instruction::Load:
629 return ARMSelectLoad(I);
630 case Instruction::Store:
631 return ARMSelectStore(I);
638 llvm::FastISel *ARM::createFastISel(FunctionLoweringInfo &funcInfo) {
639 if (EnableARMFastISel) return new ARMFastISel(funcInfo);