ARMISelLowering.h revision 212904
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
26namespace 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      WrapperJT,    // WrapperJT - A wrapper node for TargetJumpTable
38
39      CALL,         // Function call.
40      CALL_PRED,    // Function call that's predicable.
41      CALL_NOLINK,  // Function call with branch not branch-and-link.
42      tCALL,        // Thumb function call.
43      BRCOND,       // Conditional branch.
44      BR_JT,        // Jumptable branch.
45      BR2_JT,       // Jumptable branch (2 level - jumptable entry is a jump).
46      RET_FLAG,     // Return with a flag operand.
47
48      PIC_ADD,      // Add with a PC operand and a PIC label.
49
50      AND,          // ARM "and" instruction that sets the 's' flag in CPSR.
51
52      CMP,          // ARM compare instructions.
53      CMPZ,         // ARM compare that sets only Z flag.
54      CMPFP,        // ARM VFP compare instruction, sets FPSCR.
55      CMPFPw0,      // ARM VFP compare against zero instruction, sets FPSCR.
56      FMSTAT,       // ARM fmstat instruction.
57      CMOV,         // ARM conditional move instructions.
58      CNEG,         // ARM conditional negate instructions.
59
60      BCC_i64,
61
62      RBIT,         // ARM bitreverse instruction
63
64      FTOSI,        // FP to sint within a FP register.
65      FTOUI,        // FP to uint within a FP register.
66      SITOF,        // sint to FP within a FP register.
67      UITOF,        // uint to FP within a FP register.
68
69      SRL_FLAG,     // V,Flag = srl_flag X -> srl X, 1 + save carry out.
70      SRA_FLAG,     // V,Flag = sra_flag X -> sra X, 1 + save carry out.
71      RRX,          // V = RRX X, Flag     -> srl X, 1 + shift in carry flag.
72
73      VMOVRRD,      // double to two gprs.
74      VMOVDRR,      // Two gprs to double.
75
76      EH_SJLJ_SETJMP,    // SjLj exception handling setjmp.
77      EH_SJLJ_LONGJMP,   // SjLj exception handling longjmp.
78
79      TC_RETURN,    // Tail call return pseudo.
80
81      THREAD_POINTER,
82
83      DYN_ALLOC,    // Dynamic allocation on the stack.
84
85      MEMBARRIER,   // Memory barrier
86      SYNCBARRIER,  // Memory sync barrier
87
88      VCEQ,         // Vector compare equal.
89      VCGE,         // Vector compare greater than or equal.
90      VCGEU,        // Vector compare unsigned greater than or equal.
91      VCGT,         // Vector compare greater than.
92      VCGTU,        // Vector compare unsigned greater than.
93      VTST,         // Vector test bits.
94
95      // Vector shift by immediate:
96      VSHL,         // ...left
97      VSHRs,        // ...right (signed)
98      VSHRu,        // ...right (unsigned)
99      VSHLLs,       // ...left long (signed)
100      VSHLLu,       // ...left long (unsigned)
101      VSHLLi,       // ...left long (with maximum shift count)
102      VSHRN,        // ...right narrow
103
104      // Vector rounding shift by immediate:
105      VRSHRs,       // ...right (signed)
106      VRSHRu,       // ...right (unsigned)
107      VRSHRN,       // ...right narrow
108
109      // Vector saturating shift by immediate:
110      VQSHLs,       // ...left (signed)
111      VQSHLu,       // ...left (unsigned)
112      VQSHLsu,      // ...left (signed to unsigned)
113      VQSHRNs,      // ...right narrow (signed)
114      VQSHRNu,      // ...right narrow (unsigned)
115      VQSHRNsu,     // ...right narrow (signed to unsigned)
116
117      // Vector saturating rounding shift by immediate:
118      VQRSHRNs,     // ...right narrow (signed)
119      VQRSHRNu,     // ...right narrow (unsigned)
120      VQRSHRNsu,    // ...right narrow (signed to unsigned)
121
122      // Vector shift and insert:
123      VSLI,         // ...left
124      VSRI,         // ...right
125
126      // Vector get lane (VMOV scalar to ARM core register)
127      // (These are used for 8- and 16-bit element types only.)
128      VGETLANEu,    // zero-extend vector extract element
129      VGETLANEs,    // sign-extend vector extract element
130
131      // Vector move immediate and move negated immediate:
132      VMOVIMM,
133      VMVNIMM,
134
135      // Vector duplicate:
136      VDUP,
137      VDUPLANE,
138
139      // Vector shuffles:
140      VEXT,         // extract
141      VREV64,       // reverse elements within 64-bit doublewords
142      VREV32,       // reverse elements within 32-bit words
143      VREV16,       // reverse elements within 16-bit halfwords
144      VZIP,         // zip (interleave)
145      VUZP,         // unzip (deinterleave)
146      VTRN,         // transpose
147
148      // Vector multiply long:
149      VMULLs,       // ...signed
150      VMULLu,       // ...unsigned
151
152      // Operands of the standard BUILD_VECTOR node are not legalized, which
153      // is fine if BUILD_VECTORs are always lowered to shuffles or other
154      // operations, but for ARM some BUILD_VECTORs are legal as-is and their
155      // operands need to be legalized.  Define an ARM-specific version of
156      // BUILD_VECTOR for this purpose.
157      BUILD_VECTOR,
158
159      // Floating-point max and min:
160      FMAX,
161      FMIN,
162
163      // Bit-field insert
164      BFI
165    };
166  }
167
168  /// Define some predicates that are used for node matching.
169  namespace ARM {
170    /// getVFPf32Imm / getVFPf64Imm - If the given fp immediate can be
171    /// materialized with a VMOV.f32 / VMOV.f64 (i.e. fconsts / fconstd)
172    /// instruction, returns its 8-bit integer representation. Otherwise,
173    /// returns -1.
174    int getVFPf32Imm(const APFloat &FPImm);
175    int getVFPf64Imm(const APFloat &FPImm);
176    bool isBitFieldInvertedMask(unsigned v);
177  }
178
179  //===--------------------------------------------------------------------===//
180  //  ARMTargetLowering - ARM Implementation of the TargetLowering interface
181
182  class ARMTargetLowering : public TargetLowering {
183  public:
184    explicit ARMTargetLowering(TargetMachine &TM);
185
186    virtual unsigned getJumpTableEncoding(void) const;
187
188    virtual SDValue LowerOperation(SDValue Op, SelectionDAG &DAG) const;
189
190    /// ReplaceNodeResults - Replace the results of node with an illegal result
191    /// type with new values built out of custom code.
192    ///
193    virtual void ReplaceNodeResults(SDNode *N, SmallVectorImpl<SDValue>&Results,
194                                    SelectionDAG &DAG) const;
195
196    virtual SDValue PerformDAGCombine(SDNode *N, DAGCombinerInfo &DCI) const;
197
198    virtual const char *getTargetNodeName(unsigned Opcode) const;
199
200    virtual MachineBasicBlock *
201      EmitInstrWithCustomInserter(MachineInstr *MI,
202                                  MachineBasicBlock *MBB) const;
203
204    /// allowsUnalignedMemoryAccesses - Returns true if the target allows
205    /// unaligned memory accesses. of the specified type.
206    /// FIXME: Add getOptimalMemOpType to implement memcpy with NEON?
207    virtual bool allowsUnalignedMemoryAccesses(EVT VT) const;
208
209    /// isLegalAddressingMode - Return true if the addressing mode represented
210    /// by AM is legal for this target, for a load/store of the specified type.
211    virtual bool isLegalAddressingMode(const AddrMode &AM, const Type *Ty)const;
212    bool isLegalT2ScaledAddressingMode(const AddrMode &AM, EVT VT) const;
213
214    /// isLegalICmpImmediate - Return true if the specified immediate is legal
215    /// icmp immediate, that is the target has icmp instructions which can
216    /// compare a register against the immediate without having to materialize
217    /// the immediate into a register.
218    virtual bool isLegalICmpImmediate(int64_t Imm) const;
219
220    /// getPreIndexedAddressParts - returns true by value, base pointer and
221    /// offset pointer and addressing mode by reference if the node's address
222    /// can be legally represented as pre-indexed load / store address.
223    virtual bool getPreIndexedAddressParts(SDNode *N, SDValue &Base,
224                                           SDValue &Offset,
225                                           ISD::MemIndexedMode &AM,
226                                           SelectionDAG &DAG) const;
227
228    /// getPostIndexedAddressParts - returns true by value, base pointer and
229    /// offset pointer and addressing mode by reference if this node can be
230    /// combined with a load / store to form a post-indexed load / store.
231    virtual bool getPostIndexedAddressParts(SDNode *N, SDNode *Op,
232                                            SDValue &Base, SDValue &Offset,
233                                            ISD::MemIndexedMode &AM,
234                                            SelectionDAG &DAG) const;
235
236    virtual void computeMaskedBitsForTargetNode(const SDValue Op,
237                                                const APInt &Mask,
238                                                APInt &KnownZero,
239                                                APInt &KnownOne,
240                                                const SelectionDAG &DAG,
241                                                unsigned Depth) const;
242
243
244    ConstraintType getConstraintType(const std::string &Constraint) const;
245    std::pair<unsigned, const TargetRegisterClass*>
246      getRegForInlineAsmConstraint(const std::string &Constraint,
247                                   EVT VT) const;
248    std::vector<unsigned>
249    getRegClassForInlineAsmConstraint(const std::string &Constraint,
250                                      EVT VT) const;
251
252    /// LowerAsmOperandForConstraint - Lower the specified operand into the Ops
253    /// vector.  If it is invalid, don't add anything to Ops. If hasMemory is
254    /// true it means one of the asm constraint of the inline asm instruction
255    /// being processed is 'm'.
256    virtual void LowerAsmOperandForConstraint(SDValue Op,
257                                              char ConstraintLetter,
258                                              std::vector<SDValue> &Ops,
259                                              SelectionDAG &DAG) const;
260
261    const ARMSubtarget* getSubtarget() const {
262      return Subtarget;
263    }
264
265    /// getRegClassFor - Return the register class that should be used for the
266    /// specified value type.
267    virtual TargetRegisterClass *getRegClassFor(EVT VT) const;
268
269    /// getFunctionAlignment - Return the Log2 alignment of this function.
270    virtual unsigned getFunctionAlignment(const Function *F) const;
271
272    /// getMaximalGlobalOffset - Returns the maximal possible offset which can
273    /// be used for loads / stores from the global.
274    virtual unsigned getMaximalGlobalOffset() const;
275
276    /// createFastISel - This method returns a target specific FastISel object,
277    /// or null if the target does not support "fast" ISel.
278    virtual FastISel *createFastISel(FunctionLoweringInfo &funcInfo) const;
279
280    Sched::Preference getSchedulingPreference(SDNode *N) const;
281
282    unsigned getRegPressureLimit(const TargetRegisterClass *RC,
283                                 MachineFunction &MF) const;
284
285    bool isShuffleMaskLegal(const SmallVectorImpl<int> &M, EVT VT) const;
286    bool isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const;
287
288    /// isFPImmLegal - Returns true if the target can instruction select the
289    /// specified FP immediate natively. If false, the legalizer will
290    /// materialize the FP immediate as a load from a constant pool.
291    virtual bool isFPImmLegal(const APFloat &Imm, EVT VT) const;
292
293  protected:
294    std::pair<const TargetRegisterClass*, uint8_t>
295    findRepresentativeClass(EVT VT) const;
296
297  private:
298    /// Subtarget - Keep a pointer to the ARMSubtarget around so that we can
299    /// make the right decision when generating code for different targets.
300    const ARMSubtarget *Subtarget;
301
302    const TargetRegisterInfo *RegInfo;
303
304    /// ARMPCLabelIndex - Keep track of the number of ARM PC labels created.
305    ///
306    unsigned ARMPCLabelIndex;
307
308    void addTypeForNEON(EVT VT, EVT PromotedLdStVT, EVT PromotedBitwiseVT);
309    void addDRTypeForNEON(EVT VT);
310    void addQRTypeForNEON(EVT VT);
311
312    typedef SmallVector<std::pair<unsigned, SDValue>, 8> RegsToPassVector;
313    void PassF64ArgInRegs(DebugLoc dl, SelectionDAG &DAG,
314                          SDValue Chain, SDValue &Arg,
315                          RegsToPassVector &RegsToPass,
316                          CCValAssign &VA, CCValAssign &NextVA,
317                          SDValue &StackPtr,
318                          SmallVector<SDValue, 8> &MemOpChains,
319                          ISD::ArgFlagsTy Flags) const;
320    SDValue GetF64FormalArgument(CCValAssign &VA, CCValAssign &NextVA,
321                                 SDValue &Root, SelectionDAG &DAG,
322                                 DebugLoc dl) const;
323
324    CCAssignFn *CCAssignFnForNode(CallingConv::ID CC, bool Return,
325                                  bool isVarArg) const;
326    SDValue LowerMemOpCallTo(SDValue Chain, SDValue StackPtr, SDValue Arg,
327                             DebugLoc dl, SelectionDAG &DAG,
328                             const CCValAssign &VA,
329                             ISD::ArgFlagsTy Flags) const;
330    SDValue LowerEH_SJLJ_SETJMP(SDValue Op, SelectionDAG &DAG) const;
331    SDValue LowerEH_SJLJ_LONGJMP(SDValue Op, SelectionDAG &DAG) const;
332    SDValue LowerINTRINSIC_WO_CHAIN(SDValue Op, SelectionDAG &DAG,
333                                    const ARMSubtarget *Subtarget) const;
334    SDValue LowerBlockAddress(SDValue Op, SelectionDAG &DAG) const;
335    SDValue LowerGlobalAddressDarwin(SDValue Op, SelectionDAG &DAG) const;
336    SDValue LowerGlobalAddressELF(SDValue Op, SelectionDAG &DAG) const;
337    SDValue LowerGlobalTLSAddress(SDValue Op, SelectionDAG &DAG) const;
338    SDValue LowerToTLSGeneralDynamicModel(GlobalAddressSDNode *GA,
339                                            SelectionDAG &DAG) const;
340    SDValue LowerToTLSExecModels(GlobalAddressSDNode *GA,
341                                   SelectionDAG &DAG) const;
342    SDValue LowerGLOBAL_OFFSET_TABLE(SDValue Op, SelectionDAG &DAG) const;
343    SDValue LowerBR_JT(SDValue Op, SelectionDAG &DAG) const;
344    SDValue LowerSELECT(SDValue Op, SelectionDAG &DAG) const;
345    SDValue LowerSELECT_CC(SDValue Op, SelectionDAG &DAG) const;
346    SDValue LowerBR_CC(SDValue Op, SelectionDAG &DAG) const;
347    SDValue LowerFCOPYSIGN(SDValue Op, SelectionDAG &DAG) const;
348    SDValue LowerRETURNADDR(SDValue Op, SelectionDAG &DAG) const;
349    SDValue LowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) const;
350    SDValue LowerShiftRightParts(SDValue Op, SelectionDAG &DAG) const;
351    SDValue LowerShiftLeftParts(SDValue Op, SelectionDAG &DAG) const;
352    SDValue LowerFLT_ROUNDS_(SDValue Op, SelectionDAG &DAG) const;
353
354    SDValue LowerCallResult(SDValue Chain, SDValue InFlag,
355                            CallingConv::ID CallConv, bool isVarArg,
356                            const SmallVectorImpl<ISD::InputArg> &Ins,
357                            DebugLoc dl, SelectionDAG &DAG,
358                            SmallVectorImpl<SDValue> &InVals) const;
359
360    virtual SDValue
361      LowerFormalArguments(SDValue Chain,
362                           CallingConv::ID CallConv, bool isVarArg,
363                           const SmallVectorImpl<ISD::InputArg> &Ins,
364                           DebugLoc dl, SelectionDAG &DAG,
365                           SmallVectorImpl<SDValue> &InVals) const;
366
367    virtual SDValue
368      LowerCall(SDValue Chain, SDValue Callee,
369                CallingConv::ID CallConv, bool isVarArg,
370                bool &isTailCall,
371                const SmallVectorImpl<ISD::OutputArg> &Outs,
372                const SmallVectorImpl<SDValue> &OutVals,
373                const SmallVectorImpl<ISD::InputArg> &Ins,
374                DebugLoc dl, SelectionDAG &DAG,
375                SmallVectorImpl<SDValue> &InVals) const;
376
377    /// IsEligibleForTailCallOptimization - Check whether the call is eligible
378    /// for tail call optimization. Targets which want to do tail call
379    /// optimization should implement this function.
380    bool IsEligibleForTailCallOptimization(SDValue Callee,
381                                           CallingConv::ID CalleeCC,
382                                           bool isVarArg,
383                                           bool isCalleeStructRet,
384                                           bool isCallerStructRet,
385                                    const SmallVectorImpl<ISD::OutputArg> &Outs,
386                                    const SmallVectorImpl<SDValue> &OutVals,
387                                    const SmallVectorImpl<ISD::InputArg> &Ins,
388                                           SelectionDAG& DAG) const;
389    virtual SDValue
390      LowerReturn(SDValue Chain,
391                  CallingConv::ID CallConv, bool isVarArg,
392                  const SmallVectorImpl<ISD::OutputArg> &Outs,
393                  const SmallVectorImpl<SDValue> &OutVals,
394                  DebugLoc dl, SelectionDAG &DAG) const;
395
396    SDValue getARMCmp(SDValue LHS, SDValue RHS, ISD::CondCode CC,
397                      SDValue &ARMcc, SelectionDAG &DAG, DebugLoc dl) const;
398    SDValue getVFPCmp(SDValue LHS, SDValue RHS,
399                      SelectionDAG &DAG, DebugLoc dl) const;
400
401    SDValue OptimizeVFPBrcond(SDValue Op, SelectionDAG &DAG) const;
402
403    MachineBasicBlock *EmitAtomicCmpSwap(MachineInstr *MI,
404                                         MachineBasicBlock *BB,
405                                         unsigned Size) const;
406    MachineBasicBlock *EmitAtomicBinary(MachineInstr *MI,
407                                        MachineBasicBlock *BB,
408                                        unsigned Size,
409                                        unsigned BinOpcode) const;
410
411  };
412
413  namespace ARM {
414    FastISel *createFastISel(FunctionLoweringInfo &funcInfo);
415  }
416}
417
418#endif  // ARMISELLOWERING_H
419