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1 //===-- ARMISelLowering.h - ARM DAG Lowering Interface ----------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file defines the interfaces that ARM uses to lower LLVM code into a
11 // selection DAG.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef ARMISELLOWERING_H
16 #define ARMISELLOWERING_H
17 
18 #include "ARMSubtarget.h"
19 #include "llvm/Target/TargetLowering.h"
20 #include "llvm/Target/TargetRegisterInfo.h"
21 #include "llvm/CodeGen/FastISel.h"
22 #include "llvm/CodeGen/SelectionDAG.h"
23 #include "llvm/CodeGen/CallingConvLower.h"
24 #include <vector>
25 
26 namespace llvm {
27   class ARMConstantPoolValue;
28 
29   namespace ARMISD {
30     // ARM Specific DAG Nodes
31     enum NodeType {
32       // Start the numbering where the builtin ops and target ops leave off.
33       FIRST_NUMBER = ISD::BUILTIN_OP_END,
34 
35       Wrapper,      // Wrapper - A wrapper node for TargetConstantPool,
36                     // TargetExternalSymbol, and TargetGlobalAddress.
37       WrapperDYN,   // WrapperDYN - A wrapper node for TargetGlobalAddress in
38                     // DYN mode.
39       WrapperPIC,   // WrapperPIC - A wrapper node for TargetGlobalAddress in
40                     // PIC mode.
41       WrapperJT,    // WrapperJT - A wrapper node for TargetJumpTable
42 
43       CALL,         // Function call.
44       CALL_PRED,    // Function call that's predicable.
45       CALL_NOLINK,  // Function call with branch not branch-and-link.
46       tCALL,        // Thumb function call.
47       BRCOND,       // Conditional branch.
48       BR_JT,        // Jumptable branch.
49       BR2_JT,       // Jumptable branch (2 level - jumptable entry is a jump).
50       RET_FLAG,     // Return with a flag operand.
51 
52       PIC_ADD,      // Add with a PC operand and a PIC label.
53 
54       CMP,          // ARM compare instructions.
55       CMPZ,         // ARM compare that sets only Z flag.
56       CMPFP,        // ARM VFP compare instruction, sets FPSCR.
57       CMPFPw0,      // ARM VFP compare against zero instruction, sets FPSCR.
58       FMSTAT,       // ARM fmstat instruction.
59       CMOV,         // ARM conditional move instructions.
60 
61       BCC_i64,
62 
63       RBIT,         // ARM bitreverse instruction
64 
65       FTOSI,        // FP to sint within a FP register.
66       FTOUI,        // FP to uint within a FP register.
67       SITOF,        // sint to FP within a FP register.
68       UITOF,        // uint to FP within a FP register.
69 
70       SRL_FLAG,     // V,Flag = srl_flag X -> srl X, 1 + save carry out.
71       SRA_FLAG,     // V,Flag = sra_flag X -> sra X, 1 + save carry out.
72       RRX,          // V = RRX X, Flag     -> srl X, 1 + shift in carry flag.
73 
74       VMOVRRD,      // double to two gprs.
75       VMOVDRR,      // Two gprs to double.
76 
77       EH_SJLJ_SETJMP,         // SjLj exception handling setjmp.
78       EH_SJLJ_LONGJMP,        // SjLj exception handling longjmp.
79       EH_SJLJ_DISPATCHSETUP,  // SjLj exception handling dispatch setup.
80 
81       TC_RETURN,    // Tail call return pseudo.
82 
83       THREAD_POINTER,
84 
85       DYN_ALLOC,    // Dynamic allocation on the stack.
86 
87       MEMBARRIER,   // Memory barrier (DMB)
88       MEMBARRIER_MCR, // Memory barrier (MCR)
89 
90       PRELOAD,      // Preload
91 
92       VCEQ,         // Vector compare equal.
93       VCEQZ,        // Vector compare equal to zero.
94       VCGE,         // Vector compare greater than or equal.
95       VCGEZ,        // Vector compare greater than or equal to zero.
96       VCLEZ,        // Vector compare less than or equal to zero.
97       VCGEU,        // Vector compare unsigned greater than or equal.
98       VCGT,         // Vector compare greater than.
99       VCGTZ,        // Vector compare greater than zero.
100       VCLTZ,        // Vector compare less than zero.
101       VCGTU,        // Vector compare unsigned greater than.
102       VTST,         // Vector test bits.
103 
104       // Vector shift by immediate:
105       VSHL,         // ...left
106       VSHRs,        // ...right (signed)
107       VSHRu,        // ...right (unsigned)
108       VSHLLs,       // ...left long (signed)
109       VSHLLu,       // ...left long (unsigned)
110       VSHLLi,       // ...left long (with maximum shift count)
111       VSHRN,        // ...right narrow
112 
113       // Vector rounding shift by immediate:
114       VRSHRs,       // ...right (signed)
115       VRSHRu,       // ...right (unsigned)
116       VRSHRN,       // ...right narrow
117 
118       // Vector saturating shift by immediate:
119       VQSHLs,       // ...left (signed)
120       VQSHLu,       // ...left (unsigned)
121       VQSHLsu,      // ...left (signed to unsigned)
122       VQSHRNs,      // ...right narrow (signed)
123       VQSHRNu,      // ...right narrow (unsigned)
124       VQSHRNsu,     // ...right narrow (signed to unsigned)
125 
126       // Vector saturating rounding shift by immediate:
127       VQRSHRNs,     // ...right narrow (signed)
128       VQRSHRNu,     // ...right narrow (unsigned)
129       VQRSHRNsu,    // ...right narrow (signed to unsigned)
130 
131       // Vector shift and insert:
132       VSLI,         // ...left
133       VSRI,         // ...right
134 
135       // Vector get lane (VMOV scalar to ARM core register)
136       // (These are used for 8- and 16-bit element types only.)
137       VGETLANEu,    // zero-extend vector extract element
138       VGETLANEs,    // sign-extend vector extract element
139 
140       // Vector move immediate and move negated immediate:
141       VMOVIMM,
142       VMVNIMM,
143 
144       // Vector duplicate:
145       VDUP,
146       VDUPLANE,
147 
148       // Vector shuffles:
149       VEXT,         // extract
150       VREV64,       // reverse elements within 64-bit doublewords
151       VREV32,       // reverse elements within 32-bit words
152       VREV16,       // reverse elements within 16-bit halfwords
153       VZIP,         // zip (interleave)
154       VUZP,         // unzip (deinterleave)
155       VTRN,         // transpose
156       VTBL1,        // 1-register shuffle with mask
157       VTBL2,        // 2-register shuffle with mask
158 
159       // Vector multiply long:
160       VMULLs,       // ...signed
161       VMULLu,       // ...unsigned
162 
163       // Operands of the standard BUILD_VECTOR node are not legalized, which
164       // is fine if BUILD_VECTORs are always lowered to shuffles or other
165       // operations, but for ARM some BUILD_VECTORs are legal as-is and their
166       // operands need to be legalized.  Define an ARM-specific version of
167       // BUILD_VECTOR for this purpose.
168       BUILD_VECTOR,
169 
170       // Floating-point max and min:
171       FMAX,
172       FMIN,
173 
174       // Bit-field insert
175       BFI,
176 
177       // Vector OR with immediate
178       VORRIMM,
179       // Vector AND with NOT of immediate
180       VBICIMM,
181 
182       // Vector bitwise select
183       VBSL,
184 
185       // Vector load N-element structure to all lanes:
186       VLD2DUP = ISD::FIRST_TARGET_MEMORY_OPCODE,
187       VLD3DUP,
188       VLD4DUP,
189 
190       // NEON loads with post-increment base updates:
191       VLD1_UPD,
192       VLD2_UPD,
193       VLD3_UPD,
194       VLD4_UPD,
195       VLD2LN_UPD,
196       VLD3LN_UPD,
197       VLD4LN_UPD,
198       VLD2DUP_UPD,
199       VLD3DUP_UPD,
200       VLD4DUP_UPD,
201 
202       // NEON stores with post-increment base updates:
203       VST1_UPD,
204       VST2_UPD,
205       VST3_UPD,
206       VST4_UPD,
207       VST2LN_UPD,
208       VST3LN_UPD,
209       VST4LN_UPD
210     };
211   }
212 
213   /// Define some predicates that are used for node matching.
214   namespace ARM {
215     /// getVFPf32Imm / getVFPf64Imm - If the given fp immediate can be
216     /// materialized with a VMOV.f32 / VMOV.f64 (i.e. fconsts / fconstd)
217     /// instruction, returns its 8-bit integer representation. Otherwise,
218     /// returns -1.
219     int getVFPf32Imm(const APFloat &FPImm);
220     int getVFPf64Imm(const APFloat &FPImm);
221     bool isBitFieldInvertedMask(unsigned v);
222   }
223 
224   //===--------------------------------------------------------------------===//
225   //  ARMTargetLowering - ARM Implementation of the TargetLowering interface
226 
227   class ARMTargetLowering : public TargetLowering {
228   public:
229     explicit ARMTargetLowering(TargetMachine &TM);
230 
231     virtual unsigned getJumpTableEncoding(void) const;
232 
233     virtual SDValue LowerOperation(SDValue Op, SelectionDAG &DAG) const;
234 
235     /// ReplaceNodeResults - Replace the results of node with an illegal result
236     /// type with new values built out of custom code.
237     ///
238     virtual void ReplaceNodeResults(SDNode *N, SmallVectorImpl<SDValue>&Results,
239                                     SelectionDAG &DAG) const;
240 
241     virtual const char *getTargetNodeName(unsigned Opcode) const;
242 
243     virtual MachineBasicBlock *
244       EmitInstrWithCustomInserter(MachineInstr *MI,
245                                   MachineBasicBlock *MBB) const;
246 
247     SDValue PerformCMOVCombine(SDNode *N, SelectionDAG &DAG) const;
248     virtual SDValue PerformDAGCombine(SDNode *N, DAGCombinerInfo &DCI) const;
249 
250     bool isDesirableToTransformToIntegerOp(unsigned Opc, EVT VT) const;
251 
252     /// allowsUnalignedMemoryAccesses - Returns true if the target allows
253     /// unaligned memory accesses. of the specified type.
254     /// FIXME: Add getOptimalMemOpType to implement memcpy with NEON?
255     virtual bool allowsUnalignedMemoryAccesses(EVT VT) const;
256 
257     /// isLegalAddressingMode - Return true if the addressing mode represented
258     /// by AM is legal for this target, for a load/store of the specified type.
259     virtual bool isLegalAddressingMode(const AddrMode &AM, Type *Ty)const;
260     bool isLegalT2ScaledAddressingMode(const AddrMode &AM, EVT VT) const;
261 
262     /// isLegalICmpImmediate - Return true if the specified immediate is legal
263     /// icmp immediate, that is the target has icmp instructions which can
264     /// compare a register against the immediate without having to materialize
265     /// the immediate into a register.
266     virtual bool isLegalICmpImmediate(int64_t Imm) const;
267 
268     /// isLegalAddImmediate - Return true if the specified immediate is legal
269     /// add immediate, that is the target has add instructions which can
270     /// add a register and the immediate without having to materialize
271     /// the immediate into a register.
272     virtual bool isLegalAddImmediate(int64_t Imm) const;
273 
274     /// getPreIndexedAddressParts - returns true by value, base pointer and
275     /// offset pointer and addressing mode by reference if the node's address
276     /// can be legally represented as pre-indexed load / store address.
277     virtual bool getPreIndexedAddressParts(SDNode *N, SDValue &Base,
278                                            SDValue &Offset,
279                                            ISD::MemIndexedMode &AM,
280                                            SelectionDAG &DAG) const;
281 
282     /// getPostIndexedAddressParts - returns true by value, base pointer and
283     /// offset pointer and addressing mode by reference if this node can be
284     /// combined with a load / store to form a post-indexed load / store.
285     virtual bool getPostIndexedAddressParts(SDNode *N, SDNode *Op,
286                                             SDValue &Base, SDValue &Offset,
287                                             ISD::MemIndexedMode &AM,
288                                             SelectionDAG &DAG) const;
289 
290     virtual void computeMaskedBitsForTargetNode(const SDValue Op,
291                                                 const APInt &Mask,
292                                                 APInt &KnownZero,
293                                                 APInt &KnownOne,
294                                                 const SelectionDAG &DAG,
295                                                 unsigned Depth) const;
296 
297 
298     virtual bool ExpandInlineAsm(CallInst *CI) const;
299 
300     ConstraintType getConstraintType(const std::string &Constraint) const;
301 
302     /// Examine constraint string and operand type and determine a weight value.
303     /// The operand object must already have been set up with the operand type.
304     ConstraintWeight getSingleConstraintMatchWeight(
305       AsmOperandInfo &info, const char *constraint) const;
306 
307     std::pair<unsigned, const TargetRegisterClass*>
308       getRegForInlineAsmConstraint(const std::string &Constraint,
309                                    EVT VT) const;
310 
311     /// LowerAsmOperandForConstraint - Lower the specified operand into the Ops
312     /// vector.  If it is invalid, don't add anything to Ops. If hasMemory is
313     /// true it means one of the asm constraint of the inline asm instruction
314     /// being processed is 'm'.
315     virtual void LowerAsmOperandForConstraint(SDValue Op,
316                                               std::string &Constraint,
317                                               std::vector<SDValue> &Ops,
318                                               SelectionDAG &DAG) const;
319 
getSubtarget()320     const ARMSubtarget* getSubtarget() const {
321       return Subtarget;
322     }
323 
324     /// getRegClassFor - Return the register class that should be used for the
325     /// specified value type.
326     virtual TargetRegisterClass *getRegClassFor(EVT VT) const;
327 
328     /// getMaximalGlobalOffset - Returns the maximal possible offset which can
329     /// be used for loads / stores from the global.
330     virtual unsigned getMaximalGlobalOffset() const;
331 
332     /// createFastISel - This method returns a target specific FastISel object,
333     /// or null if the target does not support "fast" ISel.
334     virtual FastISel *createFastISel(FunctionLoweringInfo &funcInfo) const;
335 
336     Sched::Preference getSchedulingPreference(SDNode *N) const;
337 
338     bool isShuffleMaskLegal(const SmallVectorImpl<int> &M, EVT VT) const;
339     bool isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const;
340 
341     /// isFPImmLegal - Returns true if the target can instruction select the
342     /// specified FP immediate natively. If false, the legalizer will
343     /// materialize the FP immediate as a load from a constant pool.
344     virtual bool isFPImmLegal(const APFloat &Imm, EVT VT) const;
345 
346     virtual bool getTgtMemIntrinsic(IntrinsicInfo &Info,
347                                     const CallInst &I,
348                                     unsigned Intrinsic) const;
349   protected:
350     std::pair<const TargetRegisterClass*, uint8_t>
351     findRepresentativeClass(EVT VT) const;
352 
353   private:
354     /// Subtarget - Keep a pointer to the ARMSubtarget around so that we can
355     /// make the right decision when generating code for different targets.
356     const ARMSubtarget *Subtarget;
357 
358     const TargetRegisterInfo *RegInfo;
359 
360     const InstrItineraryData *Itins;
361 
362     /// ARMPCLabelIndex - Keep track of the number of ARM PC labels created.
363     ///
364     unsigned ARMPCLabelIndex;
365 
366     void addTypeForNEON(EVT VT, EVT PromotedLdStVT, EVT PromotedBitwiseVT);
367     void addDRTypeForNEON(EVT VT);
368     void addQRTypeForNEON(EVT VT);
369 
370     typedef SmallVector<std::pair<unsigned, SDValue>, 8> RegsToPassVector;
371     void PassF64ArgInRegs(DebugLoc dl, SelectionDAG &DAG,
372                           SDValue Chain, SDValue &Arg,
373                           RegsToPassVector &RegsToPass,
374                           CCValAssign &VA, CCValAssign &NextVA,
375                           SDValue &StackPtr,
376                           SmallVector<SDValue, 8> &MemOpChains,
377                           ISD::ArgFlagsTy Flags) const;
378     SDValue GetF64FormalArgument(CCValAssign &VA, CCValAssign &NextVA,
379                                  SDValue &Root, SelectionDAG &DAG,
380                                  DebugLoc dl) const;
381 
382     CCAssignFn *CCAssignFnForNode(CallingConv::ID CC, bool Return,
383                                   bool isVarArg) const;
384     SDValue LowerMemOpCallTo(SDValue Chain, SDValue StackPtr, SDValue Arg,
385                              DebugLoc dl, SelectionDAG &DAG,
386                              const CCValAssign &VA,
387                              ISD::ArgFlagsTy Flags) const;
388     SDValue LowerEH_SJLJ_SETJMP(SDValue Op, SelectionDAG &DAG) const;
389     SDValue LowerEH_SJLJ_LONGJMP(SDValue Op, SelectionDAG &DAG) const;
390     SDValue LowerEH_SJLJ_DISPATCHSETUP(SDValue Op, SelectionDAG &DAG) const;
391     SDValue LowerINTRINSIC_WO_CHAIN(SDValue Op, SelectionDAG &DAG,
392                                     const ARMSubtarget *Subtarget) const;
393     SDValue LowerBlockAddress(SDValue Op, SelectionDAG &DAG) const;
394     SDValue LowerGlobalAddressDarwin(SDValue Op, SelectionDAG &DAG) const;
395     SDValue LowerGlobalAddressELF(SDValue Op, SelectionDAG &DAG) const;
396     SDValue LowerGlobalTLSAddress(SDValue Op, SelectionDAG &DAG) const;
397     SDValue LowerToTLSGeneralDynamicModel(GlobalAddressSDNode *GA,
398                                             SelectionDAG &DAG) const;
399     SDValue LowerToTLSExecModels(GlobalAddressSDNode *GA,
400                                    SelectionDAG &DAG) const;
401     SDValue LowerGLOBAL_OFFSET_TABLE(SDValue Op, SelectionDAG &DAG) const;
402     SDValue LowerBR_JT(SDValue Op, SelectionDAG &DAG) const;
403     SDValue LowerSELECT(SDValue Op, SelectionDAG &DAG) const;
404     SDValue LowerSELECT_CC(SDValue Op, SelectionDAG &DAG) const;
405     SDValue LowerBR_CC(SDValue Op, SelectionDAG &DAG) const;
406     SDValue LowerFCOPYSIGN(SDValue Op, SelectionDAG &DAG) const;
407     SDValue LowerRETURNADDR(SDValue Op, SelectionDAG &DAG) const;
408     SDValue LowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) const;
409     SDValue LowerShiftRightParts(SDValue Op, SelectionDAG &DAG) const;
410     SDValue LowerShiftLeftParts(SDValue Op, SelectionDAG &DAG) const;
411     SDValue LowerFLT_ROUNDS_(SDValue Op, SelectionDAG &DAG) const;
412     SDValue LowerBUILD_VECTOR(SDValue Op, SelectionDAG &DAG,
413                               const ARMSubtarget *ST) const;
414 
415     SDValue ReconstructShuffle(SDValue Op, SelectionDAG &DAG) const;
416 
417     SDValue LowerCallResult(SDValue Chain, SDValue InFlag,
418                             CallingConv::ID CallConv, bool isVarArg,
419                             const SmallVectorImpl<ISD::InputArg> &Ins,
420                             DebugLoc dl, SelectionDAG &DAG,
421                             SmallVectorImpl<SDValue> &InVals) const;
422 
423     virtual SDValue
424       LowerFormalArguments(SDValue Chain,
425                            CallingConv::ID CallConv, bool isVarArg,
426                            const SmallVectorImpl<ISD::InputArg> &Ins,
427                            DebugLoc dl, SelectionDAG &DAG,
428                            SmallVectorImpl<SDValue> &InVals) const;
429 
430     void VarArgStyleRegisters(CCState &CCInfo, SelectionDAG &DAG,
431                               DebugLoc dl, SDValue &Chain, unsigned ArgOffset)
432       const;
433 
434     void computeRegArea(CCState &CCInfo, MachineFunction &MF,
435                         unsigned &VARegSize, unsigned &VARegSaveSize) const;
436 
437     virtual SDValue
438       LowerCall(SDValue Chain, SDValue Callee,
439                 CallingConv::ID CallConv, bool isVarArg,
440                 bool &isTailCall,
441                 const SmallVectorImpl<ISD::OutputArg> &Outs,
442                 const SmallVectorImpl<SDValue> &OutVals,
443                 const SmallVectorImpl<ISD::InputArg> &Ins,
444                 DebugLoc dl, SelectionDAG &DAG,
445                 SmallVectorImpl<SDValue> &InVals) const;
446 
447     /// HandleByVal - Target-specific cleanup for ByVal support.
448     virtual void HandleByVal(CCState *, unsigned &) const;
449 
450     /// IsEligibleForTailCallOptimization - Check whether the call is eligible
451     /// for tail call optimization. Targets which want to do tail call
452     /// optimization should implement this function.
453     bool IsEligibleForTailCallOptimization(SDValue Callee,
454                                            CallingConv::ID CalleeCC,
455                                            bool isVarArg,
456                                            bool isCalleeStructRet,
457                                            bool isCallerStructRet,
458                                     const SmallVectorImpl<ISD::OutputArg> &Outs,
459                                     const SmallVectorImpl<SDValue> &OutVals,
460                                     const SmallVectorImpl<ISD::InputArg> &Ins,
461                                            SelectionDAG& DAG) const;
462     virtual SDValue
463       LowerReturn(SDValue Chain,
464                   CallingConv::ID CallConv, bool isVarArg,
465                   const SmallVectorImpl<ISD::OutputArg> &Outs,
466                   const SmallVectorImpl<SDValue> &OutVals,
467                   DebugLoc dl, SelectionDAG &DAG) const;
468 
469     virtual bool isUsedByReturnOnly(SDNode *N) const;
470 
471     virtual bool mayBeEmittedAsTailCall(CallInst *CI) const;
472 
473     SDValue getARMCmp(SDValue LHS, SDValue RHS, ISD::CondCode CC,
474                       SDValue &ARMcc, SelectionDAG &DAG, DebugLoc dl) const;
475     SDValue getVFPCmp(SDValue LHS, SDValue RHS,
476                       SelectionDAG &DAG, DebugLoc dl) const;
477     SDValue duplicateCmp(SDValue Cmp, SelectionDAG &DAG) const;
478 
479     SDValue OptimizeVFPBrcond(SDValue Op, SelectionDAG &DAG) const;
480 
481     MachineBasicBlock *EmitAtomicCmpSwap(MachineInstr *MI,
482                                          MachineBasicBlock *BB,
483                                          unsigned Size) const;
484     MachineBasicBlock *EmitAtomicBinary(MachineInstr *MI,
485                                         MachineBasicBlock *BB,
486                                         unsigned Size,
487                                         unsigned BinOpcode) const;
488     MachineBasicBlock * EmitAtomicBinaryMinMax(MachineInstr *MI,
489                                                MachineBasicBlock *BB,
490                                                unsigned Size,
491                                                bool signExtend,
492                                                ARMCC::CondCodes Cond) const;
493 
494     bool RemapAddSubWithFlags(MachineInstr *MI, MachineBasicBlock *BB) const;
495   };
496 
497   enum NEONModImmType {
498     VMOVModImm,
499     VMVNModImm,
500     OtherModImm
501   };
502 
503 
504   namespace ARM {
505     FastISel *createFastISel(FunctionLoweringInfo &funcInfo);
506   }
507 }
508 
509 #endif  // ARMISELLOWERING_H
510