1 | //===- llvm/CodeGen/MachineBasicBlock.h -------------------------*- C++ -*-===// |
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 | // Collect the sequence of machine instructions for a basic block. |
10 | // |
11 | //===----------------------------------------------------------------------===// |
12 | |
13 | #ifndef LLVM_CODEGEN_MACHINEBASICBLOCK_H |
14 | #define LLVM_CODEGEN_MACHINEBASICBLOCK_H |
15 | |
16 | #include "llvm/ADT/GraphTraits.h" |
17 | #include "llvm/ADT/ilist.h" |
18 | #include "llvm/ADT/iterator_range.h" |
19 | #include "llvm/ADT/SparseBitVector.h" |
20 | #include "llvm/CodeGen/MachineInstr.h" |
21 | #include "llvm/CodeGen/MachineInstrBundleIterator.h" |
22 | #include "llvm/IR/DebugLoc.h" |
23 | #include "llvm/MC/LaneBitmask.h" |
24 | #include "llvm/Support/BranchProbability.h" |
25 | #include <cassert> |
26 | #include <cstdint> |
27 | #include <functional> |
28 | #include <iterator> |
29 | #include <string> |
30 | #include <vector> |
31 | |
32 | namespace llvm { |
33 | |
34 | class BasicBlock; |
35 | class MachineFunction; |
36 | class MCSymbol; |
37 | class ModuleSlotTracker; |
38 | class Pass; |
39 | class Printable; |
40 | class SlotIndexes; |
41 | class StringRef; |
42 | class raw_ostream; |
43 | class LiveIntervals; |
44 | class TargetRegisterClass; |
45 | class TargetRegisterInfo; |
46 | |
47 | // This structure uniquely identifies a basic block section. |
48 | // Possible values are |
49 | // {Type: Default, Number: (unsigned)} (These are regular section IDs) |
50 | // {Type: Exception, Number: 0} (ExceptionSectionID) |
51 | // {Type: Cold, Number: 0} (ColdSectionID) |
52 | struct MBBSectionID { |
53 | enum SectionType { |
54 | Default = 0, // Regular section (these sections are distinguished by the |
55 | // Number field). |
56 | Exception, // Special section type for exception handling blocks |
57 | Cold, // Special section type for cold blocks |
58 | } Type; |
59 | unsigned Number; |
60 | |
61 | MBBSectionID(unsigned N) : Type(Default), Number(N) {} |
62 | |
63 | // Special unique sections for cold and exception blocks. |
64 | const static MBBSectionID ColdSectionID; |
65 | const static MBBSectionID ExceptionSectionID; |
66 | |
67 | bool operator==(const MBBSectionID &Other) const { |
68 | return Type == Other.Type && Number == Other.Number; |
69 | } |
70 | |
71 | bool operator!=(const MBBSectionID &Other) const { return !(*this == Other); } |
72 | |
73 | private: |
74 | // This is only used to construct the special cold and exception sections. |
75 | MBBSectionID(SectionType T) : Type(T), Number(0) {} |
76 | }; |
77 | |
78 | template <> struct ilist_traits<MachineInstr> { |
79 | private: |
80 | friend class MachineBasicBlock; // Set by the owning MachineBasicBlock. |
81 | |
82 | MachineBasicBlock *Parent; |
83 | |
84 | using instr_iterator = |
85 | simple_ilist<MachineInstr, ilist_sentinel_tracking<true>>::iterator; |
86 | |
87 | public: |
88 | void addNodeToList(MachineInstr *N); |
89 | void removeNodeFromList(MachineInstr *N); |
90 | void transferNodesFromList(ilist_traits &FromList, instr_iterator First, |
91 | instr_iterator Last); |
92 | void deleteNode(MachineInstr *MI); |
93 | }; |
94 | |
95 | class MachineBasicBlock |
96 | : public ilist_node_with_parent<MachineBasicBlock, MachineFunction> { |
97 | public: |
98 | /// Pair of physical register and lane mask. |
99 | /// This is not simply a std::pair typedef because the members should be named |
100 | /// clearly as they both have an integer type. |
101 | struct RegisterMaskPair { |
102 | public: |
103 | MCPhysReg PhysReg; |
104 | LaneBitmask LaneMask; |
105 | |
106 | RegisterMaskPair(MCPhysReg PhysReg, LaneBitmask LaneMask) |
107 | : PhysReg(PhysReg), LaneMask(LaneMask) {} |
108 | }; |
109 | |
110 | private: |
111 | using Instructions = ilist<MachineInstr, ilist_sentinel_tracking<true>>; |
112 | |
113 | Instructions Insts; |
114 | const BasicBlock *BB; |
115 | int Number; |
116 | MachineFunction *xParent; |
117 | |
118 | /// Keep track of the predecessor / successor basic blocks. |
119 | std::vector<MachineBasicBlock *> Predecessors; |
120 | std::vector<MachineBasicBlock *> Successors; |
121 | |
122 | /// Keep track of the probabilities to the successors. This vector has the |
123 | /// same order as Successors, or it is empty if we don't use it (disable |
124 | /// optimization). |
125 | std::vector<BranchProbability> Probs; |
126 | using probability_iterator = std::vector<BranchProbability>::iterator; |
127 | using const_probability_iterator = |
128 | std::vector<BranchProbability>::const_iterator; |
129 | |
130 | Optional<uint64_t> ; |
131 | |
132 | /// Keep track of the physical registers that are livein of the basicblock. |
133 | using LiveInVector = std::vector<RegisterMaskPair>; |
134 | LiveInVector LiveIns; |
135 | |
136 | /// Alignment of the basic block. One if the basic block does not need to be |
137 | /// aligned. |
138 | Align Alignment; |
139 | |
140 | /// Indicate that this basic block is entered via an exception handler. |
141 | bool IsEHPad = false; |
142 | |
143 | /// Indicate that this basic block is potentially the target of an indirect |
144 | /// branch. |
145 | bool AddressTaken = false; |
146 | |
147 | /// Indicate that this basic block needs its symbol be emitted regardless of |
148 | /// whether the flow just falls-through to it. |
149 | bool LabelMustBeEmitted = false; |
150 | |
151 | /// Indicate that this basic block is the entry block of an EH scope, i.e., |
152 | /// the block that used to have a catchpad or cleanuppad instruction in the |
153 | /// LLVM IR. |
154 | bool IsEHScopeEntry = false; |
155 | |
156 | /// Indicates if this is a target block of a catchret. |
157 | bool IsEHCatchretTarget = false; |
158 | |
159 | /// Indicate that this basic block is the entry block of an EH funclet. |
160 | bool IsEHFuncletEntry = false; |
161 | |
162 | /// Indicate that this basic block is the entry block of a cleanup funclet. |
163 | bool IsCleanupFuncletEntry = false; |
164 | |
165 | /// With basic block sections, this stores the Section ID of the basic block. |
166 | MBBSectionID SectionID{0}; |
167 | |
168 | // Indicate that this basic block begins a section. |
169 | bool IsBeginSection = false; |
170 | |
171 | // Indicate that this basic block ends a section. |
172 | bool IsEndSection = false; |
173 | |
174 | /// Indicate that this basic block is the indirect dest of an INLINEASM_BR. |
175 | bool IsInlineAsmBrIndirectTarget = false; |
176 | |
177 | /// since getSymbol is a relatively heavy-weight operation, the symbol |
178 | /// is only computed once and is cached. |
179 | mutable MCSymbol *CachedMCSymbol = nullptr; |
180 | |
181 | /// Cached MCSymbol for this block (used if IsEHCatchRetTarget). |
182 | mutable MCSymbol *CachedEHCatchretMCSymbol = nullptr; |
183 | |
184 | /// Marks the end of the basic block. Used during basic block sections to |
185 | /// calculate the size of the basic block, or the BB section ending with it. |
186 | mutable MCSymbol *CachedEndMCSymbol = nullptr; |
187 | |
188 | // Intrusive list support |
189 | MachineBasicBlock() = default; |
190 | |
191 | explicit MachineBasicBlock(MachineFunction &MF, const BasicBlock *BB); |
192 | |
193 | ~MachineBasicBlock(); |
194 | |
195 | // MachineBasicBlocks are allocated and owned by MachineFunction. |
196 | friend class MachineFunction; |
197 | |
198 | public: |
199 | /// Return the LLVM basic block that this instance corresponded to originally. |
200 | /// Note that this may be NULL if this instance does not correspond directly |
201 | /// to an LLVM basic block. |
202 | const BasicBlock *getBasicBlock() const { return BB; } |
203 | |
204 | /// Return the name of the corresponding LLVM basic block, or an empty string. |
205 | StringRef getName() const; |
206 | |
207 | /// Return a formatted string to identify this block and its parent function. |
208 | std::string getFullName() const; |
209 | |
210 | /// Test whether this block is potentially the target of an indirect branch. |
211 | bool hasAddressTaken() const { return AddressTaken; } |
212 | |
213 | /// Set this block to reflect that it potentially is the target of an indirect |
214 | /// branch. |
215 | void setHasAddressTaken() { AddressTaken = true; } |
216 | |
217 | /// Test whether this block must have its label emitted. |
218 | bool hasLabelMustBeEmitted() const { return LabelMustBeEmitted; } |
219 | |
220 | /// Set this block to reflect that, regardless how we flow to it, we need |
221 | /// its label be emitted. |
222 | void setLabelMustBeEmitted() { LabelMustBeEmitted = true; } |
223 | |
224 | /// Return the MachineFunction containing this basic block. |
225 | const MachineFunction *getParent() const { return xParent; } |
226 | MachineFunction *getParent() { return xParent; } |
227 | |
228 | using instr_iterator = Instructions::iterator; |
229 | using const_instr_iterator = Instructions::const_iterator; |
230 | using reverse_instr_iterator = Instructions::reverse_iterator; |
231 | using const_reverse_instr_iterator = Instructions::const_reverse_iterator; |
232 | |
233 | using iterator = MachineInstrBundleIterator<MachineInstr>; |
234 | using const_iterator = MachineInstrBundleIterator<const MachineInstr>; |
235 | using reverse_iterator = MachineInstrBundleIterator<MachineInstr, true>; |
236 | using const_reverse_iterator = |
237 | MachineInstrBundleIterator<const MachineInstr, true>; |
238 | |
239 | unsigned size() const { return (unsigned)Insts.size(); } |
240 | bool empty() const { return Insts.empty(); } |
241 | |
242 | MachineInstr &instr_front() { return Insts.front(); } |
243 | MachineInstr &instr_back() { return Insts.back(); } |
244 | const MachineInstr &instr_front() const { return Insts.front(); } |
245 | const MachineInstr &instr_back() const { return Insts.back(); } |
246 | |
247 | MachineInstr &front() { return Insts.front(); } |
248 | MachineInstr &back() { return *--end(); } |
249 | const MachineInstr &front() const { return Insts.front(); } |
250 | const MachineInstr &back() const { return *--end(); } |
251 | |
252 | instr_iterator instr_begin() { return Insts.begin(); } |
253 | const_instr_iterator instr_begin() const { return Insts.begin(); } |
254 | instr_iterator instr_end() { return Insts.end(); } |
255 | const_instr_iterator instr_end() const { return Insts.end(); } |
256 | reverse_instr_iterator instr_rbegin() { return Insts.rbegin(); } |
257 | const_reverse_instr_iterator instr_rbegin() const { return Insts.rbegin(); } |
258 | reverse_instr_iterator instr_rend () { return Insts.rend(); } |
259 | const_reverse_instr_iterator instr_rend () const { return Insts.rend(); } |
260 | |
261 | using instr_range = iterator_range<instr_iterator>; |
262 | using const_instr_range = iterator_range<const_instr_iterator>; |
263 | instr_range instrs() { return instr_range(instr_begin(), instr_end()); } |
264 | const_instr_range instrs() const { |
265 | return const_instr_range(instr_begin(), instr_end()); |
266 | } |
267 | |
268 | iterator begin() { return instr_begin(); } |
269 | const_iterator begin() const { return instr_begin(); } |
270 | iterator end () { return instr_end(); } |
271 | const_iterator end () const { return instr_end(); } |
272 | reverse_iterator rbegin() { |
273 | return reverse_iterator::getAtBundleBegin(instr_rbegin()); |
274 | } |
275 | const_reverse_iterator rbegin() const { |
276 | return const_reverse_iterator::getAtBundleBegin(instr_rbegin()); |
277 | } |
278 | reverse_iterator rend() { return reverse_iterator(instr_rend()); } |
279 | const_reverse_iterator rend() const { |
280 | return const_reverse_iterator(instr_rend()); |
281 | } |
282 | |
283 | /// Support for MachineInstr::getNextNode(). |
284 | static Instructions MachineBasicBlock::*getSublistAccess(MachineInstr *) { |
285 | return &MachineBasicBlock::Insts; |
286 | } |
287 | |
288 | inline iterator_range<iterator> terminators() { |
289 | return make_range(getFirstTerminator(), end()); |
290 | } |
291 | inline iterator_range<const_iterator> terminators() const { |
292 | return make_range(getFirstTerminator(), end()); |
293 | } |
294 | |
295 | /// Returns a range that iterates over the phis in the basic block. |
296 | inline iterator_range<iterator> phis() { |
297 | return make_range(begin(), getFirstNonPHI()); |
298 | } |
299 | inline iterator_range<const_iterator> phis() const { |
300 | return const_cast<MachineBasicBlock *>(this)->phis(); |
301 | } |
302 | |
303 | // Machine-CFG iterators |
304 | using pred_iterator = std::vector<MachineBasicBlock *>::iterator; |
305 | using const_pred_iterator = std::vector<MachineBasicBlock *>::const_iterator; |
306 | using succ_iterator = std::vector<MachineBasicBlock *>::iterator; |
307 | using const_succ_iterator = std::vector<MachineBasicBlock *>::const_iterator; |
308 | using pred_reverse_iterator = |
309 | std::vector<MachineBasicBlock *>::reverse_iterator; |
310 | using const_pred_reverse_iterator = |
311 | std::vector<MachineBasicBlock *>::const_reverse_iterator; |
312 | using succ_reverse_iterator = |
313 | std::vector<MachineBasicBlock *>::reverse_iterator; |
314 | using const_succ_reverse_iterator = |
315 | std::vector<MachineBasicBlock *>::const_reverse_iterator; |
316 | pred_iterator pred_begin() { return Predecessors.begin(); } |
317 | const_pred_iterator pred_begin() const { return Predecessors.begin(); } |
318 | pred_iterator pred_end() { return Predecessors.end(); } |
319 | const_pred_iterator pred_end() const { return Predecessors.end(); } |
320 | pred_reverse_iterator pred_rbegin() |
321 | { return Predecessors.rbegin();} |
322 | const_pred_reverse_iterator pred_rbegin() const |
323 | { return Predecessors.rbegin();} |
324 | pred_reverse_iterator pred_rend() |
325 | { return Predecessors.rend(); } |
326 | const_pred_reverse_iterator pred_rend() const |
327 | { return Predecessors.rend(); } |
328 | unsigned pred_size() const { |
329 | return (unsigned)Predecessors.size(); |
330 | } |
331 | bool pred_empty() const { return Predecessors.empty(); } |
332 | succ_iterator succ_begin() { return Successors.begin(); } |
333 | const_succ_iterator succ_begin() const { return Successors.begin(); } |
334 | succ_iterator succ_end() { return Successors.end(); } |
335 | const_succ_iterator succ_end() const { return Successors.end(); } |
336 | succ_reverse_iterator succ_rbegin() |
337 | { return Successors.rbegin(); } |
338 | const_succ_reverse_iterator succ_rbegin() const |
339 | { return Successors.rbegin(); } |
340 | succ_reverse_iterator succ_rend() |
341 | { return Successors.rend(); } |
342 | const_succ_reverse_iterator succ_rend() const |
343 | { return Successors.rend(); } |
344 | unsigned succ_size() const { |
345 | return (unsigned)Successors.size(); |
346 | } |
347 | bool succ_empty() const { return Successors.empty(); } |
348 | |
349 | inline iterator_range<pred_iterator> predecessors() { |
350 | return make_range(pred_begin(), pred_end()); |
351 | } |
352 | inline iterator_range<const_pred_iterator> predecessors() const { |
353 | return make_range(pred_begin(), pred_end()); |
354 | } |
355 | inline iterator_range<succ_iterator> successors() { |
356 | return make_range(succ_begin(), succ_end()); |
357 | } |
358 | inline iterator_range<const_succ_iterator> successors() const { |
359 | return make_range(succ_begin(), succ_end()); |
360 | } |
361 | |
362 | // LiveIn management methods. |
363 | |
364 | /// Adds the specified register as a live in. Note that it is an error to add |
365 | /// the same register to the same set more than once unless the intention is |
366 | /// to call sortUniqueLiveIns after all registers are added. |
367 | void addLiveIn(MCRegister PhysReg, |
368 | LaneBitmask LaneMask = LaneBitmask::getAll()) { |
369 | LiveIns.push_back(RegisterMaskPair(PhysReg, LaneMask)); |
370 | } |
371 | void addLiveIn(const RegisterMaskPair &RegMaskPair) { |
372 | LiveIns.push_back(RegMaskPair); |
373 | } |
374 | |
375 | /// Sorts and uniques the LiveIns vector. It can be significantly faster to do |
376 | /// this than repeatedly calling isLiveIn before calling addLiveIn for every |
377 | /// LiveIn insertion. |
378 | void sortUniqueLiveIns(); |
379 | |
380 | /// Clear live in list. |
381 | void clearLiveIns(); |
382 | |
383 | /// Add PhysReg as live in to this block, and ensure that there is a copy of |
384 | /// PhysReg to a virtual register of class RC. Return the virtual register |
385 | /// that is a copy of the live in PhysReg. |
386 | Register addLiveIn(MCRegister PhysReg, const TargetRegisterClass *RC); |
387 | |
388 | /// Remove the specified register from the live in set. |
389 | void removeLiveIn(MCPhysReg Reg, |
390 | LaneBitmask LaneMask = LaneBitmask::getAll()); |
391 | |
392 | /// Return true if the specified register is in the live in set. |
393 | bool isLiveIn(MCPhysReg Reg, |
394 | LaneBitmask LaneMask = LaneBitmask::getAll()) const; |
395 | |
396 | // Iteration support for live in sets. These sets are kept in sorted |
397 | // order by their register number. |
398 | using livein_iterator = LiveInVector::const_iterator; |
399 | #ifndef NDEBUG |
400 | /// Unlike livein_begin, this method does not check that the liveness |
401 | /// information is accurate. Still for debug purposes it may be useful |
402 | /// to have iterators that won't assert if the liveness information |
403 | /// is not current. |
404 | livein_iterator livein_begin_dbg() const { return LiveIns.begin(); } |
405 | iterator_range<livein_iterator> liveins_dbg() const { |
406 | return make_range(livein_begin_dbg(), livein_end()); |
407 | } |
408 | #endif |
409 | livein_iterator livein_begin() const; |
410 | livein_iterator livein_end() const { return LiveIns.end(); } |
411 | bool livein_empty() const { return LiveIns.empty(); } |
412 | iterator_range<livein_iterator> liveins() const { |
413 | return make_range(livein_begin(), livein_end()); |
414 | } |
415 | |
416 | /// Remove entry from the livein set and return iterator to the next. |
417 | livein_iterator removeLiveIn(livein_iterator I); |
418 | |
419 | /// Get the clobber mask for the start of this basic block. Funclets use this |
420 | /// to prevent register allocation across funclet transitions. |
421 | const uint32_t *getBeginClobberMask(const TargetRegisterInfo *TRI) const; |
422 | |
423 | /// Get the clobber mask for the end of the basic block. |
424 | /// \see getBeginClobberMask() |
425 | const uint32_t *getEndClobberMask(const TargetRegisterInfo *TRI) const; |
426 | |
427 | /// Return alignment of the basic block. |
428 | Align getAlignment() const { return Alignment; } |
429 | |
430 | /// Set alignment of the basic block. |
431 | void setAlignment(Align A) { Alignment = A; } |
432 | |
433 | /// Returns true if the block is a landing pad. That is this basic block is |
434 | /// entered via an exception handler. |
435 | bool isEHPad() const { return IsEHPad; } |
436 | |
437 | /// Indicates the block is a landing pad. That is this basic block is entered |
438 | /// via an exception handler. |
439 | void setIsEHPad(bool V = true) { IsEHPad = V; } |
440 | |
441 | bool hasEHPadSuccessor() const; |
442 | |
443 | /// Returns true if this is the entry block of the function. |
444 | bool isEntryBlock() const; |
445 | |
446 | /// Returns true if this is the entry block of an EH scope, i.e., the block |
447 | /// that used to have a catchpad or cleanuppad instruction in the LLVM IR. |
448 | bool isEHScopeEntry() const { return IsEHScopeEntry; } |
449 | |
450 | /// Indicates if this is the entry block of an EH scope, i.e., the block that |
451 | /// that used to have a catchpad or cleanuppad instruction in the LLVM IR. |
452 | void setIsEHScopeEntry(bool V = true) { IsEHScopeEntry = V; } |
453 | |
454 | /// Returns true if this is a target block of a catchret. |
455 | bool isEHCatchretTarget() const { return IsEHCatchretTarget; } |
456 | |
457 | /// Indicates if this is a target block of a catchret. |
458 | void setIsEHCatchretTarget(bool V = true) { IsEHCatchretTarget = V; } |
459 | |
460 | /// Returns true if this is the entry block of an EH funclet. |
461 | bool isEHFuncletEntry() const { return IsEHFuncletEntry; } |
462 | |
463 | /// Indicates if this is the entry block of an EH funclet. |
464 | void setIsEHFuncletEntry(bool V = true) { IsEHFuncletEntry = V; } |
465 | |
466 | /// Returns true if this is the entry block of a cleanup funclet. |
467 | bool isCleanupFuncletEntry() const { return IsCleanupFuncletEntry; } |
468 | |
469 | /// Indicates if this is the entry block of a cleanup funclet. |
470 | void setIsCleanupFuncletEntry(bool V = true) { IsCleanupFuncletEntry = V; } |
471 | |
472 | /// Returns true if this block begins any section. |
473 | bool isBeginSection() const { return IsBeginSection; } |
474 | |
475 | /// Returns true if this block ends any section. |
476 | bool isEndSection() const { return IsEndSection; } |
477 | |
478 | void setIsBeginSection(bool V = true) { IsBeginSection = V; } |
479 | |
480 | void setIsEndSection(bool V = true) { IsEndSection = V; } |
481 | |
482 | /// Returns the section ID of this basic block. |
483 | MBBSectionID getSectionID() const { return SectionID; } |
484 | |
485 | /// Returns the unique section ID number of this basic block. |
486 | unsigned getSectionIDNum() const { |
487 | return ((unsigned)MBBSectionID::SectionType::Cold) - |
488 | ((unsigned)SectionID.Type) + SectionID.Number; |
489 | } |
490 | |
491 | /// Sets the section ID for this basic block. |
492 | void setSectionID(MBBSectionID V) { SectionID = V; } |
493 | |
494 | /// Returns the MCSymbol marking the end of this basic block. |
495 | MCSymbol *getEndSymbol() const; |
496 | |
497 | /// Returns true if this block may have an INLINEASM_BR (overestimate, by |
498 | /// checking if any of the successors are indirect targets of any inlineasm_br |
499 | /// in the function). |
500 | bool mayHaveInlineAsmBr() const; |
501 | |
502 | /// Returns true if this is the indirect dest of an INLINEASM_BR. |
503 | bool isInlineAsmBrIndirectTarget() const { |
504 | return IsInlineAsmBrIndirectTarget; |
505 | } |
506 | |
507 | /// Indicates if this is the indirect dest of an INLINEASM_BR. |
508 | void setIsInlineAsmBrIndirectTarget(bool V = true) { |
509 | IsInlineAsmBrIndirectTarget = V; |
510 | } |
511 | |
512 | /// Returns true if it is legal to hoist instructions into this block. |
513 | bool isLegalToHoistInto() const; |
514 | |
515 | // Code Layout methods. |
516 | |
517 | /// Move 'this' block before or after the specified block. This only moves |
518 | /// the block, it does not modify the CFG or adjust potential fall-throughs at |
519 | /// the end of the block. |
520 | void moveBefore(MachineBasicBlock *NewAfter); |
521 | void moveAfter(MachineBasicBlock *NewBefore); |
522 | |
523 | /// Returns true if this and MBB belong to the same section. |
524 | bool sameSection(const MachineBasicBlock *MBB) const { |
525 | return getSectionID() == MBB->getSectionID(); |
526 | } |
527 | |
528 | /// Update the terminator instructions in block to account for changes to |
529 | /// block layout which may have been made. PreviousLayoutSuccessor should be |
530 | /// set to the block which may have been used as fallthrough before the block |
531 | /// layout was modified. If the block previously fell through to that block, |
532 | /// it may now need a branch. If it previously branched to another block, it |
533 | /// may now be able to fallthrough to the current layout successor. |
534 | void updateTerminator(MachineBasicBlock *PreviousLayoutSuccessor); |
535 | |
536 | // Machine-CFG mutators |
537 | |
538 | /// Add Succ as a successor of this MachineBasicBlock. The Predecessors list |
539 | /// of Succ is automatically updated. PROB parameter is stored in |
540 | /// Probabilities list. The default probability is set as unknown. Mixing |
541 | /// known and unknown probabilities in successor list is not allowed. When all |
542 | /// successors have unknown probabilities, 1 / N is returned as the |
543 | /// probability for each successor, where N is the number of successors. |
544 | /// |
545 | /// Note that duplicate Machine CFG edges are not allowed. |
546 | void addSuccessor(MachineBasicBlock *Succ, |
547 | BranchProbability Prob = BranchProbability::getUnknown()); |
548 | |
549 | /// Add Succ as a successor of this MachineBasicBlock. The Predecessors list |
550 | /// of Succ is automatically updated. The probability is not provided because |
551 | /// BPI is not available (e.g. -O0 is used), in which case edge probabilities |
552 | /// won't be used. Using this interface can save some space. |
553 | void addSuccessorWithoutProb(MachineBasicBlock *Succ); |
554 | |
555 | /// Set successor probability of a given iterator. |
556 | void setSuccProbability(succ_iterator I, BranchProbability Prob); |
557 | |
558 | /// Normalize probabilities of all successors so that the sum of them becomes |
559 | /// one. This is usually done when the current update on this MBB is done, and |
560 | /// the sum of its successors' probabilities is not guaranteed to be one. The |
561 | /// user is responsible for the correct use of this function. |
562 | /// MBB::removeSuccessor() has an option to do this automatically. |
563 | void normalizeSuccProbs() { |
564 | BranchProbability::normalizeProbabilities(Probs.begin(), Probs.end()); |
565 | } |
566 | |
567 | /// Validate successors' probabilities and check if the sum of them is |
568 | /// approximate one. This only works in DEBUG mode. |
569 | void validateSuccProbs() const; |
570 | |
571 | /// Remove successor from the successors list of this MachineBasicBlock. The |
572 | /// Predecessors list of Succ is automatically updated. |
573 | /// If NormalizeSuccProbs is true, then normalize successors' probabilities |
574 | /// after the successor is removed. |
575 | void removeSuccessor(MachineBasicBlock *Succ, |
576 | bool NormalizeSuccProbs = false); |
577 | |
578 | /// Remove specified successor from the successors list of this |
579 | /// MachineBasicBlock. The Predecessors list of Succ is automatically updated. |
580 | /// If NormalizeSuccProbs is true, then normalize successors' probabilities |
581 | /// after the successor is removed. |
582 | /// Return the iterator to the element after the one removed. |
583 | succ_iterator removeSuccessor(succ_iterator I, |
584 | bool NormalizeSuccProbs = false); |
585 | |
586 | /// Replace successor OLD with NEW and update probability info. |
587 | void replaceSuccessor(MachineBasicBlock *Old, MachineBasicBlock *New); |
588 | |
589 | /// Copy a successor (and any probability info) from original block to this |
590 | /// block's. Uses an iterator into the original blocks successors. |
591 | /// |
592 | /// This is useful when doing a partial clone of successors. Afterward, the |
593 | /// probabilities may need to be normalized. |
594 | void copySuccessor(MachineBasicBlock *Orig, succ_iterator I); |
595 | |
596 | /// Split the old successor into old plus new and updates the probability |
597 | /// info. |
598 | void splitSuccessor(MachineBasicBlock *Old, MachineBasicBlock *New, |
599 | bool NormalizeSuccProbs = false); |
600 | |
601 | /// Transfers all the successors from MBB to this machine basic block (i.e., |
602 | /// copies all the successors FromMBB and remove all the successors from |
603 | /// FromMBB). |
604 | void transferSuccessors(MachineBasicBlock *FromMBB); |
605 | |
606 | /// Transfers all the successors, as in transferSuccessors, and update PHI |
607 | /// operands in the successor blocks which refer to FromMBB to refer to this. |
608 | void transferSuccessorsAndUpdatePHIs(MachineBasicBlock *FromMBB); |
609 | |
610 | /// move all pseudo probes in this block to the end of /c ToMBB To and tag |
611 | /// them dangling. |
612 | void moveAndDanglePseudoProbes(MachineBasicBlock *ToMBB); |
613 | |
614 | /// Return true if any of the successors have probabilities attached to them. |
615 | bool hasSuccessorProbabilities() const { return !Probs.empty(); } |
616 | |
617 | /// Return true if the specified MBB is a predecessor of this block. |
618 | bool isPredecessor(const MachineBasicBlock *MBB) const; |
619 | |
620 | /// Return true if the specified MBB is a successor of this block. |
621 | bool isSuccessor(const MachineBasicBlock *MBB) const; |
622 | |
623 | /// Return true if the specified MBB will be emitted immediately after this |
624 | /// block, such that if this block exits by falling through, control will |
625 | /// transfer to the specified MBB. Note that MBB need not be a successor at |
626 | /// all, for example if this block ends with an unconditional branch to some |
627 | /// other block. |
628 | bool isLayoutSuccessor(const MachineBasicBlock *MBB) const; |
629 | |
630 | /// Return the fallthrough block if the block can implicitly |
631 | /// transfer control to the block after it by falling off the end of |
632 | /// it. This should return null if it can reach the block after |
633 | /// it, but it uses an explicit branch to do so (e.g., a table |
634 | /// jump). Non-null return is a conservative answer. |
635 | MachineBasicBlock *getFallThrough(); |
636 | |
637 | /// Return true if the block can implicitly transfer control to the |
638 | /// block after it by falling off the end of it. This should return |
639 | /// false if it can reach the block after it, but it uses an |
640 | /// explicit branch to do so (e.g., a table jump). True is a |
641 | /// conservative answer. |
642 | bool canFallThrough(); |
643 | |
644 | /// Returns a pointer to the first instruction in this block that is not a |
645 | /// PHINode instruction. When adding instructions to the beginning of the |
646 | /// basic block, they should be added before the returned value, not before |
647 | /// the first instruction, which might be PHI. |
648 | /// Returns end() is there's no non-PHI instruction. |
649 | iterator getFirstNonPHI(); |
650 | |
651 | /// Return the first instruction in MBB after I that is not a PHI or a label. |
652 | /// This is the correct point to insert lowered copies at the beginning of a |
653 | /// basic block that must be before any debugging information. |
654 | iterator SkipPHIsAndLabels(iterator I); |
655 | |
656 | /// Return the first instruction in MBB after I that is not a PHI, label or |
657 | /// debug. This is the correct point to insert copies at the beginning of a |
658 | /// basic block. |
659 | iterator SkipPHIsLabelsAndDebug(iterator I, bool SkipPseudoOp = true); |
660 | |
661 | /// Returns an iterator to the first terminator instruction of this basic |
662 | /// block. If a terminator does not exist, it returns end(). |
663 | iterator getFirstTerminator(); |
664 | const_iterator getFirstTerminator() const { |
665 | return const_cast<MachineBasicBlock *>(this)->getFirstTerminator(); |
666 | } |
667 | |
668 | /// Same getFirstTerminator but it ignores bundles and return an |
669 | /// instr_iterator instead. |
670 | instr_iterator getFirstInstrTerminator(); |
671 | |
672 | /// Returns an iterator to the first non-debug instruction in the basic block, |
673 | /// or end(). Skip any pseudo probe operation if \c SkipPseudoOp is true. |
674 | /// Pseudo probes are like debug instructions which do not turn into real |
675 | /// machine code. We try to use the function to skip both debug instructions |
676 | /// and pseudo probe operations to avoid API proliferation. This should work |
677 | /// most of the time when considering optimizing the rest of code in the |
678 | /// block, except for certain cases where pseudo probes are designed to block |
679 | /// the optimizations. For example, code merge like optimizations are supposed |
680 | /// to be blocked by pseudo probes for better AutoFDO profile quality. |
681 | /// Therefore, they should be considered as a valid instruction when this |
682 | /// function is called in a context of such optimizations. On the other hand, |
683 | /// \c SkipPseudoOp should be true when it's used in optimizations that |
684 | /// unlikely hurt profile quality, e.g., without block merging. The default |
685 | /// value of \c SkipPseudoOp is set to true to maximize code quality in |
686 | /// general, with an explict false value passed in in a few places like branch |
687 | /// folding and if-conversion to favor profile quality. |
688 | iterator getFirstNonDebugInstr(bool SkipPseudoOp = true); |
689 | const_iterator getFirstNonDebugInstr(bool SkipPseudoOp = true) const { |
690 | return const_cast<MachineBasicBlock *>(this)->getFirstNonDebugInstr( |
691 | SkipPseudoOp); |
692 | } |
693 | |
694 | /// Returns an iterator to the last non-debug instruction in the basic block, |
695 | /// or end(). Skip any pseudo operation if \c SkipPseudoOp is true. |
696 | /// Pseudo probes are like debug instructions which do not turn into real |
697 | /// machine code. We try to use the function to skip both debug instructions |
698 | /// and pseudo probe operations to avoid API proliferation. This should work |
699 | /// most of the time when considering optimizing the rest of code in the |
700 | /// block, except for certain cases where pseudo probes are designed to block |
701 | /// the optimizations. For example, code merge like optimizations are supposed |
702 | /// to be blocked by pseudo probes for better AutoFDO profile quality. |
703 | /// Therefore, they should be considered as a valid instruction when this |
704 | /// function is called in a context of such optimizations. On the other hand, |
705 | /// \c SkipPseudoOp should be true when it's used in optimizations that |
706 | /// unlikely hurt profile quality, e.g., without block merging. The default |
707 | /// value of \c SkipPseudoOp is set to true to maximize code quality in |
708 | /// general, with an explict false value passed in in a few places like branch |
709 | /// folding and if-conversion to favor profile quality. |
710 | iterator getLastNonDebugInstr(bool SkipPseudoOp = true); |
711 | const_iterator getLastNonDebugInstr(bool SkipPseudoOp = true) const { |
712 | return const_cast<MachineBasicBlock *>(this)->getLastNonDebugInstr( |
713 | SkipPseudoOp); |
714 | } |
715 | |
716 | /// Convenience function that returns true if the block ends in a return |
717 | /// instruction. |
718 | bool isReturnBlock() const { |
719 | return !empty() && back().isReturn(); |
720 | } |
721 | |
722 | /// Convenience function that returns true if the bock ends in a EH scope |
723 | /// return instruction. |
724 | bool isEHScopeReturnBlock() const { |
725 | return !empty() && back().isEHScopeReturn(); |
726 | } |
727 | |
728 | /// Split a basic block into 2 pieces at \p SplitPoint. A new block will be |
729 | /// inserted after this block, and all instructions after \p SplitInst moved |
730 | /// to it (\p SplitInst will be in the original block). If \p LIS is provided, |
731 | /// LiveIntervals will be appropriately updated. \return the newly inserted |
732 | /// block. |
733 | /// |
734 | /// If \p UpdateLiveIns is true, this will ensure the live ins list is |
735 | /// accurate, including for physreg uses/defs in the original block. |
736 | MachineBasicBlock *splitAt(MachineInstr &SplitInst, bool UpdateLiveIns = true, |
737 | LiveIntervals *LIS = nullptr); |
738 | |
739 | /// Split the critical edge from this block to the given successor block, and |
740 | /// return the newly created block, or null if splitting is not possible. |
741 | /// |
742 | /// This function updates LiveVariables, MachineDominatorTree, and |
743 | /// MachineLoopInfo, as applicable. |
744 | MachineBasicBlock * |
745 | SplitCriticalEdge(MachineBasicBlock *Succ, Pass &P, |
746 | std::vector<SparseBitVector<>> *LiveInSets = nullptr); |
747 | |
748 | /// Check if the edge between this block and the given successor \p |
749 | /// Succ, can be split. If this returns true a subsequent call to |
750 | /// SplitCriticalEdge is guaranteed to return a valid basic block if |
751 | /// no changes occurred in the meantime. |
752 | bool canSplitCriticalEdge(const MachineBasicBlock *Succ) const; |
753 | |
754 | void pop_front() { Insts.pop_front(); } |
755 | void pop_back() { Insts.pop_back(); } |
756 | void push_back(MachineInstr *MI) { Insts.push_back(MI); } |
757 | |
758 | /// Insert MI into the instruction list before I, possibly inside a bundle. |
759 | /// |
760 | /// If the insertion point is inside a bundle, MI will be added to the bundle, |
761 | /// otherwise MI will not be added to any bundle. That means this function |
762 | /// alone can't be used to prepend or append instructions to bundles. See |
763 | /// MIBundleBuilder::insert() for a more reliable way of doing that. |
764 | instr_iterator insert(instr_iterator I, MachineInstr *M); |
765 | |
766 | /// Insert a range of instructions into the instruction list before I. |
767 | template<typename IT> |
768 | void insert(iterator I, IT S, IT E) { |
769 | assert((I == end() || I->getParent() == this) && |
770 | "iterator points outside of basic block" ); |
771 | Insts.insert(I.getInstrIterator(), S, E); |
772 | } |
773 | |
774 | /// Insert MI into the instruction list before I. |
775 | iterator insert(iterator I, MachineInstr *MI) { |
776 | assert((I == end() || I->getParent() == this) && |
777 | "iterator points outside of basic block" ); |
778 | assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() && |
779 | "Cannot insert instruction with bundle flags" ); |
780 | return Insts.insert(I.getInstrIterator(), MI); |
781 | } |
782 | |
783 | /// Insert MI into the instruction list after I. |
784 | iterator insertAfter(iterator I, MachineInstr *MI) { |
785 | assert((I == end() || I->getParent() == this) && |
786 | "iterator points outside of basic block" ); |
787 | assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() && |
788 | "Cannot insert instruction with bundle flags" ); |
789 | return Insts.insertAfter(I.getInstrIterator(), MI); |
790 | } |
791 | |
792 | /// If I is bundled then insert MI into the instruction list after the end of |
793 | /// the bundle, otherwise insert MI immediately after I. |
794 | instr_iterator insertAfterBundle(instr_iterator I, MachineInstr *MI) { |
795 | assert((I == instr_end() || I->getParent() == this) && |
796 | "iterator points outside of basic block" ); |
797 | assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() && |
798 | "Cannot insert instruction with bundle flags" ); |
799 | while (I->isBundledWithSucc()) |
800 | ++I; |
801 | return Insts.insertAfter(I, MI); |
802 | } |
803 | |
804 | /// Remove an instruction from the instruction list and delete it. |
805 | /// |
806 | /// If the instruction is part of a bundle, the other instructions in the |
807 | /// bundle will still be bundled after removing the single instruction. |
808 | instr_iterator erase(instr_iterator I); |
809 | |
810 | /// Remove an instruction from the instruction list and delete it. |
811 | /// |
812 | /// If the instruction is part of a bundle, the other instructions in the |
813 | /// bundle will still be bundled after removing the single instruction. |
814 | instr_iterator erase_instr(MachineInstr *I) { |
815 | return erase(instr_iterator(I)); |
816 | } |
817 | |
818 | /// Remove a range of instructions from the instruction list and delete them. |
819 | iterator erase(iterator I, iterator E) { |
820 | return Insts.erase(I.getInstrIterator(), E.getInstrIterator()); |
821 | } |
822 | |
823 | /// Remove an instruction or bundle from the instruction list and delete it. |
824 | /// |
825 | /// If I points to a bundle of instructions, they are all erased. |
826 | iterator erase(iterator I) { |
827 | return erase(I, std::next(I)); |
828 | } |
829 | |
830 | /// Remove an instruction from the instruction list and delete it. |
831 | /// |
832 | /// If I is the head of a bundle of instructions, the whole bundle will be |
833 | /// erased. |
834 | iterator erase(MachineInstr *I) { |
835 | return erase(iterator(I)); |
836 | } |
837 | |
838 | /// Remove the unbundled instruction from the instruction list without |
839 | /// deleting it. |
840 | /// |
841 | /// This function can not be used to remove bundled instructions, use |
842 | /// remove_instr to remove individual instructions from a bundle. |
843 | MachineInstr *remove(MachineInstr *I) { |
844 | assert(!I->isBundled() && "Cannot remove bundled instructions" ); |
845 | return Insts.remove(instr_iterator(I)); |
846 | } |
847 | |
848 | /// Remove the possibly bundled instruction from the instruction list |
849 | /// without deleting it. |
850 | /// |
851 | /// If the instruction is part of a bundle, the other instructions in the |
852 | /// bundle will still be bundled after removing the single instruction. |
853 | MachineInstr *remove_instr(MachineInstr *I); |
854 | |
855 | void clear() { |
856 | Insts.clear(); |
857 | } |
858 | |
859 | /// Take an instruction from MBB 'Other' at the position From, and insert it |
860 | /// into this MBB right before 'Where'. |
861 | /// |
862 | /// If From points to a bundle of instructions, the whole bundle is moved. |
863 | void splice(iterator Where, MachineBasicBlock *Other, iterator From) { |
864 | // The range splice() doesn't allow noop moves, but this one does. |
865 | if (Where != From) |
866 | splice(Where, Other, From, std::next(From)); |
867 | } |
868 | |
869 | /// Take a block of instructions from MBB 'Other' in the range [From, To), |
870 | /// and insert them into this MBB right before 'Where'. |
871 | /// |
872 | /// The instruction at 'Where' must not be included in the range of |
873 | /// instructions to move. |
874 | void splice(iterator Where, MachineBasicBlock *Other, |
875 | iterator From, iterator To) { |
876 | Insts.splice(Where.getInstrIterator(), Other->Insts, |
877 | From.getInstrIterator(), To.getInstrIterator()); |
878 | } |
879 | |
880 | /// This method unlinks 'this' from the containing function, and returns it, |
881 | /// but does not delete it. |
882 | MachineBasicBlock *removeFromParent(); |
883 | |
884 | /// This method unlinks 'this' from the containing function and deletes it. |
885 | void eraseFromParent(); |
886 | |
887 | /// Given a machine basic block that branched to 'Old', change the code and |
888 | /// CFG so that it branches to 'New' instead. |
889 | void ReplaceUsesOfBlockWith(MachineBasicBlock *Old, MachineBasicBlock *New); |
890 | |
891 | /// Update all phi nodes in this basic block to refer to basic block \p New |
892 | /// instead of basic block \p Old. |
893 | void replacePhiUsesWith(MachineBasicBlock *Old, MachineBasicBlock *New); |
894 | |
895 | /// Find the next valid DebugLoc starting at MBBI, skipping any DBG_VALUE |
896 | /// and DBG_LABEL instructions. Return UnknownLoc if there is none. |
897 | DebugLoc findDebugLoc(instr_iterator MBBI); |
898 | DebugLoc findDebugLoc(iterator MBBI) { |
899 | return findDebugLoc(MBBI.getInstrIterator()); |
900 | } |
901 | |
902 | /// Has exact same behavior as @ref findDebugLoc (it also |
903 | /// searches from the first to the last MI of this MBB) except |
904 | /// that this takes reverse iterator. |
905 | DebugLoc rfindDebugLoc(reverse_instr_iterator MBBI); |
906 | DebugLoc rfindDebugLoc(reverse_iterator MBBI) { |
907 | return rfindDebugLoc(MBBI.getInstrIterator()); |
908 | } |
909 | |
910 | /// Find the previous valid DebugLoc preceding MBBI, skipping and DBG_VALUE |
911 | /// instructions. Return UnknownLoc if there is none. |
912 | DebugLoc findPrevDebugLoc(instr_iterator MBBI); |
913 | DebugLoc findPrevDebugLoc(iterator MBBI) { |
914 | return findPrevDebugLoc(MBBI.getInstrIterator()); |
915 | } |
916 | |
917 | /// Has exact same behavior as @ref findPrevDebugLoc (it also |
918 | /// searches from the last to the first MI of this MBB) except |
919 | /// that this takes reverse iterator. |
920 | DebugLoc rfindPrevDebugLoc(reverse_instr_iterator MBBI); |
921 | DebugLoc rfindPrevDebugLoc(reverse_iterator MBBI) { |
922 | return rfindPrevDebugLoc(MBBI.getInstrIterator()); |
923 | } |
924 | |
925 | /// Find and return the merged DebugLoc of the branch instructions of the |
926 | /// block. Return UnknownLoc if there is none. |
927 | DebugLoc findBranchDebugLoc(); |
928 | |
929 | /// Possible outcome of a register liveness query to computeRegisterLiveness() |
930 | enum LivenessQueryResult { |
931 | LQR_Live, ///< Register is known to be (at least partially) live. |
932 | LQR_Dead, ///< Register is known to be fully dead. |
933 | LQR_Unknown ///< Register liveness not decidable from local neighborhood. |
934 | }; |
935 | |
936 | /// Return whether (physical) register \p Reg has been defined and not |
937 | /// killed as of just before \p Before. |
938 | /// |
939 | /// Search is localised to a neighborhood of \p Neighborhood instructions |
940 | /// before (searching for defs or kills) and \p Neighborhood instructions |
941 | /// after (searching just for defs) \p Before. |
942 | /// |
943 | /// \p Reg must be a physical register. |
944 | LivenessQueryResult computeRegisterLiveness(const TargetRegisterInfo *TRI, |
945 | MCRegister Reg, |
946 | const_iterator Before, |
947 | unsigned Neighborhood = 10) const; |
948 | |
949 | // Debugging methods. |
950 | void dump() const; |
951 | void print(raw_ostream &OS, const SlotIndexes * = nullptr, |
952 | bool IsStandalone = true) const; |
953 | void print(raw_ostream &OS, ModuleSlotTracker &MST, |
954 | const SlotIndexes * = nullptr, bool IsStandalone = true) const; |
955 | |
956 | enum PrintNameFlag { |
957 | PrintNameIr = (1 << 0), ///< Add IR name where available |
958 | PrintNameAttributes = (1 << 1), ///< Print attributes |
959 | }; |
960 | |
961 | void printName(raw_ostream &os, unsigned printNameFlags = PrintNameIr, |
962 | ModuleSlotTracker *moduleSlotTracker = nullptr) const; |
963 | |
964 | // Printing method used by LoopInfo. |
965 | void printAsOperand(raw_ostream &OS, bool PrintType = true) const; |
966 | |
967 | /// MachineBasicBlocks are uniquely numbered at the function level, unless |
968 | /// they're not in a MachineFunction yet, in which case this will return -1. |
969 | int getNumber() const { return Number; } |
970 | void setNumber(int N) { Number = N; } |
971 | |
972 | /// Return the MCSymbol for this basic block. |
973 | MCSymbol *getSymbol() const; |
974 | |
975 | /// Return the EHCatchret Symbol for this basic block. |
976 | MCSymbol *getEHCatchretSymbol() const; |
977 | |
978 | Optional<uint64_t> () const { |
979 | return IrrLoopHeaderWeight; |
980 | } |
981 | |
982 | void (uint64_t Weight) { |
983 | IrrLoopHeaderWeight = Weight; |
984 | } |
985 | |
986 | private: |
987 | /// Return probability iterator corresponding to the I successor iterator. |
988 | probability_iterator getProbabilityIterator(succ_iterator I); |
989 | const_probability_iterator |
990 | getProbabilityIterator(const_succ_iterator I) const; |
991 | |
992 | friend class MachineBranchProbabilityInfo; |
993 | friend class MIPrinter; |
994 | |
995 | /// Return probability of the edge from this block to MBB. This method should |
996 | /// NOT be called directly, but by using getEdgeProbability method from |
997 | /// MachineBranchProbabilityInfo class. |
998 | BranchProbability getSuccProbability(const_succ_iterator Succ) const; |
999 | |
1000 | // Methods used to maintain doubly linked list of blocks... |
1001 | friend struct ilist_callback_traits<MachineBasicBlock>; |
1002 | |
1003 | // Machine-CFG mutators |
1004 | |
1005 | /// Add Pred as a predecessor of this MachineBasicBlock. Don't do this |
1006 | /// unless you know what you're doing, because it doesn't update Pred's |
1007 | /// successors list. Use Pred->addSuccessor instead. |
1008 | void addPredecessor(MachineBasicBlock *Pred); |
1009 | |
1010 | /// Remove Pred as a predecessor of this MachineBasicBlock. Don't do this |
1011 | /// unless you know what you're doing, because it doesn't update Pred's |
1012 | /// successors list. Use Pred->removeSuccessor instead. |
1013 | void removePredecessor(MachineBasicBlock *Pred); |
1014 | }; |
1015 | |
1016 | raw_ostream& operator<<(raw_ostream &OS, const MachineBasicBlock &MBB); |
1017 | |
1018 | /// Prints a machine basic block reference. |
1019 | /// |
1020 | /// The format is: |
1021 | /// %bb.5 - a machine basic block with MBB.getNumber() == 5. |
1022 | /// |
1023 | /// Usage: OS << printMBBReference(MBB) << '\n'; |
1024 | Printable printMBBReference(const MachineBasicBlock &MBB); |
1025 | |
1026 | // This is useful when building IndexedMaps keyed on basic block pointers. |
1027 | struct MBB2NumberFunctor { |
1028 | using argument_type = const MachineBasicBlock *; |
1029 | unsigned operator()(const MachineBasicBlock *MBB) const { |
1030 | return MBB->getNumber(); |
1031 | } |
1032 | }; |
1033 | |
1034 | //===--------------------------------------------------------------------===// |
1035 | // GraphTraits specializations for machine basic block graphs (machine-CFGs) |
1036 | //===--------------------------------------------------------------------===// |
1037 | |
1038 | // Provide specializations of GraphTraits to be able to treat a |
1039 | // MachineFunction as a graph of MachineBasicBlocks. |
1040 | // |
1041 | |
1042 | template <> struct GraphTraits<MachineBasicBlock *> { |
1043 | using NodeRef = MachineBasicBlock *; |
1044 | using ChildIteratorType = MachineBasicBlock::succ_iterator; |
1045 | |
1046 | static NodeRef getEntryNode(MachineBasicBlock *BB) { return BB; } |
1047 | static ChildIteratorType child_begin(NodeRef N) { return N->succ_begin(); } |
1048 | static ChildIteratorType child_end(NodeRef N) { return N->succ_end(); } |
1049 | }; |
1050 | |
1051 | template <> struct GraphTraits<const MachineBasicBlock *> { |
1052 | using NodeRef = const MachineBasicBlock *; |
1053 | using ChildIteratorType = MachineBasicBlock::const_succ_iterator; |
1054 | |
1055 | static NodeRef getEntryNode(const MachineBasicBlock *BB) { return BB; } |
1056 | static ChildIteratorType child_begin(NodeRef N) { return N->succ_begin(); } |
1057 | static ChildIteratorType child_end(NodeRef N) { return N->succ_end(); } |
1058 | }; |
1059 | |
1060 | // Provide specializations of GraphTraits to be able to treat a |
1061 | // MachineFunction as a graph of MachineBasicBlocks and to walk it |
1062 | // in inverse order. Inverse order for a function is considered |
1063 | // to be when traversing the predecessor edges of a MBB |
1064 | // instead of the successor edges. |
1065 | // |
1066 | template <> struct GraphTraits<Inverse<MachineBasicBlock*>> { |
1067 | using NodeRef = MachineBasicBlock *; |
1068 | using ChildIteratorType = MachineBasicBlock::pred_iterator; |
1069 | |
1070 | static NodeRef getEntryNode(Inverse<MachineBasicBlock *> G) { |
1071 | return G.Graph; |
1072 | } |
1073 | |
1074 | static ChildIteratorType child_begin(NodeRef N) { return N->pred_begin(); } |
1075 | static ChildIteratorType child_end(NodeRef N) { return N->pred_end(); } |
1076 | }; |
1077 | |
1078 | template <> struct GraphTraits<Inverse<const MachineBasicBlock*>> { |
1079 | using NodeRef = const MachineBasicBlock *; |
1080 | using ChildIteratorType = MachineBasicBlock::const_pred_iterator; |
1081 | |
1082 | static NodeRef getEntryNode(Inverse<const MachineBasicBlock *> G) { |
1083 | return G.Graph; |
1084 | } |
1085 | |
1086 | static ChildIteratorType child_begin(NodeRef N) { return N->pred_begin(); } |
1087 | static ChildIteratorType child_end(NodeRef N) { return N->pred_end(); } |
1088 | }; |
1089 | |
1090 | /// MachineInstrSpan provides an interface to get an iteration range |
1091 | /// containing the instruction it was initialized with, along with all |
1092 | /// those instructions inserted prior to or following that instruction |
1093 | /// at some point after the MachineInstrSpan is constructed. |
1094 | class MachineInstrSpan { |
1095 | MachineBasicBlock &MBB; |
1096 | MachineBasicBlock::iterator I, B, E; |
1097 | |
1098 | public: |
1099 | MachineInstrSpan(MachineBasicBlock::iterator I, MachineBasicBlock *BB) |
1100 | : MBB(*BB), I(I), B(I == MBB.begin() ? MBB.end() : std::prev(I)), |
1101 | E(std::next(I)) { |
1102 | assert(I == BB->end() || I->getParent() == BB); |
1103 | } |
1104 | |
1105 | MachineBasicBlock::iterator begin() { |
1106 | return B == MBB.end() ? MBB.begin() : std::next(B); |
1107 | } |
1108 | MachineBasicBlock::iterator end() { return E; } |
1109 | bool empty() { return begin() == end(); } |
1110 | |
1111 | MachineBasicBlock::iterator getInitial() { return I; } |
1112 | }; |
1113 | |
1114 | /// Increment \p It until it points to a non-debug instruction or to \p End |
1115 | /// and return the resulting iterator. This function should only be used |
1116 | /// MachineBasicBlock::{iterator, const_iterator, instr_iterator, |
1117 | /// const_instr_iterator} and the respective reverse iterators. |
1118 | template <typename IterT> |
1119 | inline IterT skipDebugInstructionsForward(IterT It, IterT End, |
1120 | bool SkipPseudoOp = true) { |
1121 | while (It != End && |
1122 | (It->isDebugInstr() || (SkipPseudoOp && It->isPseudoProbe()))) |
1123 | ++It; |
1124 | return It; |
1125 | } |
1126 | |
1127 | /// Decrement \p It until it points to a non-debug instruction or to \p Begin |
1128 | /// and return the resulting iterator. This function should only be used |
1129 | /// MachineBasicBlock::{iterator, const_iterator, instr_iterator, |
1130 | /// const_instr_iterator} and the respective reverse iterators. |
1131 | template <class IterT> |
1132 | inline IterT skipDebugInstructionsBackward(IterT It, IterT Begin, |
1133 | bool SkipPseudoOp = true) { |
1134 | while (It != Begin && |
1135 | (It->isDebugInstr() || (SkipPseudoOp && It->isPseudoProbe()))) |
1136 | --It; |
1137 | return It; |
1138 | } |
1139 | |
1140 | /// Increment \p It, then continue incrementing it while it points to a debug |
1141 | /// instruction. A replacement for std::next. |
1142 | template <typename IterT> |
1143 | inline IterT next_nodbg(IterT It, IterT End, bool SkipPseudoOp = true) { |
1144 | return skipDebugInstructionsForward(std::next(It), End, SkipPseudoOp); |
1145 | } |
1146 | |
1147 | /// Decrement \p It, then continue decrementing it while it points to a debug |
1148 | /// instruction. A replacement for std::prev. |
1149 | template <typename IterT> |
1150 | inline IterT prev_nodbg(IterT It, IterT Begin, bool SkipPseudoOp = true) { |
1151 | return skipDebugInstructionsBackward(std::prev(It), Begin, SkipPseudoOp); |
1152 | } |
1153 | |
1154 | /// Construct a range iterator which begins at \p It and moves forwards until |
1155 | /// \p End is reached, skipping any debug instructions. |
1156 | template <typename IterT> |
1157 | inline auto instructionsWithoutDebug(IterT It, IterT End, |
1158 | bool SkipPseudoOp = true) { |
1159 | return make_filter_range(make_range(It, End), [=](const MachineInstr &MI) { |
1160 | return !MI.isDebugInstr() && !(SkipPseudoOp && MI.isPseudoProbe()); |
1161 | }); |
1162 | } |
1163 | |
1164 | } // end namespace llvm |
1165 | |
1166 | #endif // LLVM_CODEGEN_MACHINEBASICBLOCK_H |
1167 | |