1 //===-- SelectionDAGBuilder.h - Selection-DAG building --------------------===//
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 implements routines for translating from LLVM IR into SelectionDAG IR.
12 //===----------------------------------------------------------------------===//
14 #ifndef SELECTIONDAGBUILDER_H
15 #define SELECTIONDAGBUILDER_H
17 #include "llvm/ADT/APInt.h"
18 #include "llvm/ADT/DenseMap.h"
19 #include "llvm/CodeGen/SelectionDAG.h"
20 #include "llvm/CodeGen/SelectionDAGNodes.h"
21 #include "llvm/CodeGen/ValueTypes.h"
22 #include "llvm/IR/Constants.h"
23 #include "llvm/Support/CallSite.h"
24 #include "llvm/Support/ErrorHandling.h"
36 class ExtractElementInst;
37 class ExtractValueInst;
44 class FunctionLoweringInfo;
45 class GetElementPtrInst;
51 class InsertElementInst;
52 class InsertValueInst;
55 class MachineBasicBlock;
57 class MachineRegisterInfo;
65 class ShuffleVectorInst;
70 class TargetLibraryInfo;
74 class UnreachableInst;
78 //===----------------------------------------------------------------------===//
79 /// SelectionDAGBuilder - This is the common target-independent lowering
80 /// implementation that is parameterized by a TargetLowering object.
82 class SelectionDAGBuilder {
83 /// CurInst - The current instruction being visited
84 const Instruction *CurInst;
86 DenseMap<const Value*, SDValue> NodeMap;
88 /// UnusedArgNodeMap - Maps argument value for unused arguments. This is used
89 /// to preserve debug information for incoming arguments.
90 DenseMap<const Value*, SDValue> UnusedArgNodeMap;
92 /// DanglingDebugInfo - Helper type for DanglingDebugInfoMap.
93 class DanglingDebugInfo {
94 const DbgValueInst* DI;
98 DanglingDebugInfo() : DI(0), dl(DebugLoc()), SDNodeOrder(0) { }
99 DanglingDebugInfo(const DbgValueInst *di, DebugLoc DL, unsigned SDNO) :
100 DI(di), dl(DL), SDNodeOrder(SDNO) { }
101 const DbgValueInst* getDI() { return DI; }
102 DebugLoc getdl() { return dl; }
103 unsigned getSDNodeOrder() { return SDNodeOrder; }
106 /// DanglingDebugInfoMap - Keeps track of dbg_values for which we have not
107 /// yet seen the referent. We defer handling these until we do see it.
108 DenseMap<const Value*, DanglingDebugInfo> DanglingDebugInfoMap;
111 /// PendingLoads - Loads are not emitted to the program immediately. We bunch
112 /// them up and then emit token factor nodes when possible. This allows us to
113 /// get simple disambiguation between loads without worrying about alias
115 SmallVector<SDValue, 8> PendingLoads;
118 /// PendingExports - CopyToReg nodes that copy values to virtual registers
119 /// for export to other blocks need to be emitted before any terminator
120 /// instruction, but they have no other ordering requirements. We bunch them
121 /// up and the emit a single tokenfactor for them just before terminator
123 SmallVector<SDValue, 8> PendingExports;
125 /// SDNodeOrder - A unique monotonically increasing number used to order the
126 /// SDNodes we create.
127 unsigned SDNodeOrder;
129 /// Case - A struct to record the Value for a switch case, and the
130 /// case's target basic block.
133 const Constant *High;
134 MachineBasicBlock* BB;
135 uint32_t ExtraWeight;
137 Case() : Low(0), High(0), BB(0), ExtraWeight(0) { }
138 Case(const Constant *low, const Constant *high, MachineBasicBlock *bb,
139 uint32_t extraweight) : Low(low), High(high), BB(bb),
140 ExtraWeight(extraweight) { }
143 const APInt &rHigh = cast<ConstantInt>(High)->getValue();
144 const APInt &rLow = cast<ConstantInt>(Low)->getValue();
145 return (rHigh - rLow + 1ULL);
151 MachineBasicBlock* BB;
153 uint32_t ExtraWeight;
155 CaseBits(uint64_t mask, MachineBasicBlock* bb, unsigned bits,
157 Mask(mask), BB(bb), Bits(bits), ExtraWeight(Weight) { }
160 typedef std::vector<Case> CaseVector;
161 typedef std::vector<CaseBits> CaseBitsVector;
162 typedef CaseVector::iterator CaseItr;
163 typedef std::pair<CaseItr, CaseItr> CaseRange;
165 /// CaseRec - A struct with ctor used in lowering switches to a binary tree
166 /// of conditional branches.
168 CaseRec(MachineBasicBlock *bb, const Constant *lt, const Constant *ge,
170 CaseBB(bb), LT(lt), GE(ge), Range(r) {}
172 /// CaseBB - The MBB in which to emit the compare and branch
173 MachineBasicBlock *CaseBB;
174 /// LT, GE - If nonzero, we know the current case value must be less-than or
175 /// greater-than-or-equal-to these Constants.
178 /// Range - A pair of iterators representing the range of case values to be
179 /// processed at this point in the binary search tree.
183 typedef std::vector<CaseRec> CaseRecVector;
186 bool operator()(const CaseBits &C1, const CaseBits &C2) {
187 return C1.Bits > C2.Bits;
191 size_t Clusterify(CaseVector &Cases, const SwitchInst &SI);
193 /// CaseBlock - This structure is used to communicate between
194 /// SelectionDAGBuilder and SDISel for the code generation of additional basic
195 /// blocks needed by multi-case switch statements.
197 CaseBlock(ISD::CondCode cc, const Value *cmplhs, const Value *cmprhs,
198 const Value *cmpmiddle,
199 MachineBasicBlock *truebb, MachineBasicBlock *falsebb,
200 MachineBasicBlock *me,
201 uint32_t trueweight = 0, uint32_t falseweight = 0)
202 : CC(cc), CmpLHS(cmplhs), CmpMHS(cmpmiddle), CmpRHS(cmprhs),
203 TrueBB(truebb), FalseBB(falsebb), ThisBB(me),
204 TrueWeight(trueweight), FalseWeight(falseweight) { }
206 // CC - the condition code to use for the case block's setcc node
209 // CmpLHS/CmpRHS/CmpMHS - The LHS/MHS/RHS of the comparison to emit.
210 // Emit by default LHS op RHS. MHS is used for range comparisons:
211 // If MHS is not null: (LHS <= MHS) and (MHS <= RHS).
212 const Value *CmpLHS, *CmpMHS, *CmpRHS;
214 // TrueBB/FalseBB - the block to branch to if the setcc is true/false.
215 MachineBasicBlock *TrueBB, *FalseBB;
217 // ThisBB - the block into which to emit the code for the setcc and branches
218 MachineBasicBlock *ThisBB;
220 // TrueWeight/FalseWeight - branch weights.
221 uint32_t TrueWeight, FalseWeight;
225 JumpTable(unsigned R, unsigned J, MachineBasicBlock *M,
226 MachineBasicBlock *D): Reg(R), JTI(J), MBB(M), Default(D) {}
228 /// Reg - the virtual register containing the index of the jump table entry
231 /// JTI - the JumpTableIndex for this jump table in the function.
233 /// MBB - the MBB into which to emit the code for the indirect jump.
234 MachineBasicBlock *MBB;
235 /// Default - the MBB of the default bb, which is a successor of the range
236 /// check MBB. This is when updating PHI nodes in successors.
237 MachineBasicBlock *Default;
239 struct JumpTableHeader {
240 JumpTableHeader(APInt F, APInt L, const Value *SV, MachineBasicBlock *H,
242 First(F), Last(L), SValue(SV), HeaderBB(H), Emitted(E) {}
246 MachineBasicBlock *HeaderBB;
249 typedef std::pair<JumpTableHeader, JumpTable> JumpTableBlock;
252 BitTestCase(uint64_t M, MachineBasicBlock* T, MachineBasicBlock* Tr,
254 Mask(M), ThisBB(T), TargetBB(Tr), ExtraWeight(Weight) { }
256 MachineBasicBlock *ThisBB;
257 MachineBasicBlock *TargetBB;
258 uint32_t ExtraWeight;
261 typedef SmallVector<BitTestCase, 3> BitTestInfo;
263 struct BitTestBlock {
264 BitTestBlock(APInt F, APInt R, const Value* SV,
265 unsigned Rg, MVT RgVT, bool E,
266 MachineBasicBlock* P, MachineBasicBlock* D,
267 const BitTestInfo& C):
268 First(F), Range(R), SValue(SV), Reg(Rg), RegVT(RgVT), Emitted(E),
269 Parent(P), Default(D), Cases(C) { }
276 MachineBasicBlock *Parent;
277 MachineBasicBlock *Default;
282 // TLI - This is information that describes the available target features we
283 // need for lowering. This indicates when operations are unavailable,
284 // implemented with a libcall, etc.
285 const TargetMachine &TM;
286 const TargetLowering &TLI;
288 const DataLayout *TD;
290 const TargetLibraryInfo *LibInfo;
292 /// SwitchCases - Vector of CaseBlock structures used to communicate
293 /// SwitchInst code generation information.
294 std::vector<CaseBlock> SwitchCases;
295 /// JTCases - Vector of JumpTable structures used to communicate
296 /// SwitchInst code generation information.
297 std::vector<JumpTableBlock> JTCases;
298 /// BitTestCases - Vector of BitTestBlock structures used to communicate
299 /// SwitchInst code generation information.
300 std::vector<BitTestBlock> BitTestCases;
302 // Emit PHI-node-operand constants only once even if used by multiple
304 DenseMap<const Constant *, unsigned> ConstantsOut;
306 /// FuncInfo - Information about the function as a whole.
308 FunctionLoweringInfo &FuncInfo;
310 /// OptLevel - What optimization level we're generating code for.
312 CodeGenOpt::Level OptLevel;
314 /// GFI - Garbage collection metadata for the function.
317 /// LPadToCallSiteMap - Map a landing pad to the call site indexes.
318 DenseMap<MachineBasicBlock*, SmallVector<unsigned, 4> > LPadToCallSiteMap;
320 /// HasTailCall - This is set to true if a call in the current
321 /// block has been translated as a tail call. In this case,
322 /// no subsequent DAG nodes should be created.
326 LLVMContext *Context;
328 SelectionDAGBuilder(SelectionDAG &dag, FunctionLoweringInfo &funcinfo,
329 CodeGenOpt::Level ol)
330 : CurInst(NULL), SDNodeOrder(0), TM(dag.getTarget()),
331 TLI(dag.getTargetLoweringInfo()),
332 DAG(dag), FuncInfo(funcinfo), OptLevel(ol),
336 void init(GCFunctionInfo *gfi, AliasAnalysis &aa,
337 const TargetLibraryInfo *li);
339 /// clear - Clear out the current SelectionDAG and the associated
340 /// state and prepare this SelectionDAGBuilder object to be used
341 /// for a new block. This doesn't clear out information about
342 /// additional blocks that are needed to complete switch lowering
343 /// or PHI node updating; that information is cleared out as it is
347 /// clearDanglingDebugInfo - Clear the dangling debug information
348 /// map. This function is separated from the clear so that debug
349 /// information that is dangling in a basic block can be properly
350 /// resolved in a different basic block. This allows the
351 /// SelectionDAG to resolve dangling debug information attached
353 void clearDanglingDebugInfo();
355 /// getRoot - Return the current virtual root of the Selection DAG,
356 /// flushing any PendingLoad items. This must be done before emitting
357 /// a store or any other node that may need to be ordered after any
358 /// prior load instructions.
362 /// getControlRoot - Similar to getRoot, but instead of flushing all the
363 /// PendingLoad items, flush all the PendingExports items. It is necessary
364 /// to do this before emitting a terminator instruction.
366 SDValue getControlRoot();
368 SDLoc getCurSDLoc() const {
369 assert(CurInst && "CurInst NULL");
370 return SDLoc(CurInst, SDNodeOrder);
373 DebugLoc getCurDebugLoc() const {
374 return CurInst ? CurInst->getDebugLoc() : DebugLoc();
377 unsigned getSDNodeOrder() const { return SDNodeOrder; }
379 void CopyValueToVirtualRegister(const Value *V, unsigned Reg);
381 /// AssignOrderingToNode - Assign an ordering to the node. The order is gotten
382 /// from how the code appeared in the source. The ordering is used by the
383 /// scheduler to effectively turn off scheduling.
384 void AssignOrderingToNode(const SDNode *Node);
386 void visit(const Instruction &I);
388 void visit(unsigned Opcode, const User &I);
390 // resolveDanglingDebugInfo - if we saw an earlier dbg_value referring to V,
391 // generate the debug data structures now that we've seen its definition.
392 void resolveDanglingDebugInfo(const Value *V, SDValue Val);
393 SDValue getValue(const Value *V);
394 SDValue getNonRegisterValue(const Value *V);
395 SDValue getValueImpl(const Value *V);
397 void setValue(const Value *V, SDValue NewN) {
398 SDValue &N = NodeMap[V];
399 assert(N.getNode() == 0 && "Already set a value for this node!");
403 void setUnusedArgValue(const Value *V, SDValue NewN) {
404 SDValue &N = UnusedArgNodeMap[V];
405 assert(N.getNode() == 0 && "Already set a value for this node!");
409 void FindMergedConditions(const Value *Cond, MachineBasicBlock *TBB,
410 MachineBasicBlock *FBB, MachineBasicBlock *CurBB,
411 MachineBasicBlock *SwitchBB, unsigned Opc);
412 void EmitBranchForMergedCondition(const Value *Cond, MachineBasicBlock *TBB,
413 MachineBasicBlock *FBB,
414 MachineBasicBlock *CurBB,
415 MachineBasicBlock *SwitchBB);
416 bool ShouldEmitAsBranches(const std::vector<CaseBlock> &Cases);
417 bool isExportableFromCurrentBlock(const Value *V, const BasicBlock *FromBB);
418 void CopyToExportRegsIfNeeded(const Value *V);
419 void ExportFromCurrentBlock(const Value *V);
420 void LowerCallTo(ImmutableCallSite CS, SDValue Callee, bool IsTailCall,
421 MachineBasicBlock *LandingPad = NULL);
423 /// UpdateSplitBlock - When an MBB was split during scheduling, update the
424 /// references that ned to refer to the last resulting block.
425 void UpdateSplitBlock(MachineBasicBlock *First, MachineBasicBlock *Last);
428 // Terminator instructions.
429 void visitRet(const ReturnInst &I);
430 void visitBr(const BranchInst &I);
431 void visitSwitch(const SwitchInst &I);
432 void visitIndirectBr(const IndirectBrInst &I);
433 void visitUnreachable(const UnreachableInst &I) { /* noop */ }
435 // Helpers for visitSwitch
436 bool handleSmallSwitchRange(CaseRec& CR,
437 CaseRecVector& WorkList,
439 MachineBasicBlock* Default,
440 MachineBasicBlock *SwitchBB);
441 bool handleJTSwitchCase(CaseRec& CR,
442 CaseRecVector& WorkList,
444 MachineBasicBlock* Default,
445 MachineBasicBlock *SwitchBB);
446 bool handleBTSplitSwitchCase(CaseRec& CR,
447 CaseRecVector& WorkList,
449 MachineBasicBlock* Default,
450 MachineBasicBlock *SwitchBB);
451 bool handleBitTestsSwitchCase(CaseRec& CR,
452 CaseRecVector& WorkList,
454 MachineBasicBlock* Default,
455 MachineBasicBlock *SwitchBB);
457 uint32_t getEdgeWeight(const MachineBasicBlock *Src,
458 const MachineBasicBlock *Dst) const;
459 void addSuccessorWithWeight(MachineBasicBlock *Src, MachineBasicBlock *Dst,
460 uint32_t Weight = 0);
462 void visitSwitchCase(CaseBlock &CB,
463 MachineBasicBlock *SwitchBB);
464 void visitBitTestHeader(BitTestBlock &B, MachineBasicBlock *SwitchBB);
465 void visitBitTestCase(BitTestBlock &BB,
466 MachineBasicBlock* NextMBB,
467 uint32_t BranchWeightToNext,
470 MachineBasicBlock *SwitchBB);
471 void visitJumpTable(JumpTable &JT);
472 void visitJumpTableHeader(JumpTable &JT, JumpTableHeader &JTH,
473 MachineBasicBlock *SwitchBB);
476 // These all get lowered before this pass.
477 void visitInvoke(const InvokeInst &I);
478 void visitResume(const ResumeInst &I);
480 void visitBinary(const User &I, unsigned OpCode);
481 void visitShift(const User &I, unsigned Opcode);
482 void visitAdd(const User &I) { visitBinary(I, ISD::ADD); }
483 void visitFAdd(const User &I) { visitBinary(I, ISD::FADD); }
484 void visitSub(const User &I) { visitBinary(I, ISD::SUB); }
485 void visitFSub(const User &I);
486 void visitMul(const User &I) { visitBinary(I, ISD::MUL); }
487 void visitFMul(const User &I) { visitBinary(I, ISD::FMUL); }
488 void visitURem(const User &I) { visitBinary(I, ISD::UREM); }
489 void visitSRem(const User &I) { visitBinary(I, ISD::SREM); }
490 void visitFRem(const User &I) { visitBinary(I, ISD::FREM); }
491 void visitUDiv(const User &I) { visitBinary(I, ISD::UDIV); }
492 void visitSDiv(const User &I);
493 void visitFDiv(const User &I) { visitBinary(I, ISD::FDIV); }
494 void visitAnd (const User &I) { visitBinary(I, ISD::AND); }
495 void visitOr (const User &I) { visitBinary(I, ISD::OR); }
496 void visitXor (const User &I) { visitBinary(I, ISD::XOR); }
497 void visitShl (const User &I) { visitShift(I, ISD::SHL); }
498 void visitLShr(const User &I) { visitShift(I, ISD::SRL); }
499 void visitAShr(const User &I) { visitShift(I, ISD::SRA); }
500 void visitICmp(const User &I);
501 void visitFCmp(const User &I);
502 // Visit the conversion instructions
503 void visitTrunc(const User &I);
504 void visitZExt(const User &I);
505 void visitSExt(const User &I);
506 void visitFPTrunc(const User &I);
507 void visitFPExt(const User &I);
508 void visitFPToUI(const User &I);
509 void visitFPToSI(const User &I);
510 void visitUIToFP(const User &I);
511 void visitSIToFP(const User &I);
512 void visitPtrToInt(const User &I);
513 void visitIntToPtr(const User &I);
514 void visitBitCast(const User &I);
516 void visitExtractElement(const User &I);
517 void visitInsertElement(const User &I);
518 void visitShuffleVector(const User &I);
520 void visitExtractValue(const ExtractValueInst &I);
521 void visitInsertValue(const InsertValueInst &I);
522 void visitLandingPad(const LandingPadInst &I);
524 void visitGetElementPtr(const User &I);
525 void visitSelect(const User &I);
527 void visitAlloca(const AllocaInst &I);
528 void visitLoad(const LoadInst &I);
529 void visitStore(const StoreInst &I);
530 void visitAtomicCmpXchg(const AtomicCmpXchgInst &I);
531 void visitAtomicRMW(const AtomicRMWInst &I);
532 void visitFence(const FenceInst &I);
533 void visitPHI(const PHINode &I);
534 void visitCall(const CallInst &I);
535 bool visitMemCmpCall(const CallInst &I);
536 bool visitUnaryFloatCall(const CallInst &I, unsigned Opcode);
537 void visitAtomicLoad(const LoadInst &I);
538 void visitAtomicStore(const StoreInst &I);
540 void visitInlineAsm(ImmutableCallSite CS);
541 const char *visitIntrinsicCall(const CallInst &I, unsigned Intrinsic);
542 void visitTargetIntrinsic(const CallInst &I, unsigned Intrinsic);
544 void visitVAStart(const CallInst &I);
545 void visitVAArg(const VAArgInst &I);
546 void visitVAEnd(const CallInst &I);
547 void visitVACopy(const CallInst &I);
549 void visitUserOp1(const Instruction &I) {
550 llvm_unreachable("UserOp1 should not exist at instruction selection time!");
552 void visitUserOp2(const Instruction &I) {
553 llvm_unreachable("UserOp2 should not exist at instruction selection time!");
556 void HandlePHINodesInSuccessorBlocks(const BasicBlock *LLVMBB);
558 /// EmitFuncArgumentDbgValue - If V is an function argument then create
559 /// corresponding DBG_VALUE machine instruction for it now. At the end of
560 /// instruction selection, they will be inserted to the entry BB.
561 bool EmitFuncArgumentDbgValue(const Value *V, MDNode *Variable,
562 int64_t Offset, const SDValue &N);
565 } // end namespace llvm