1 //===-- MachineFunction.cpp -----------------------------------------------===//
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 // Collect native machine code information for a function. This allows
11 // target-specific information about the generated code to be stored with each
12 // function.
13 //
14 //===----------------------------------------------------------------------===//
15
16 #include "llvm/CodeGen/MachineFunction.h"
17 #include "llvm/ADT/STLExtras.h"
18 #include "llvm/ADT/SmallString.h"
19 #include "llvm/Analysis/ConstantFolding.h"
20 #include "llvm/CodeGen/MachineConstantPool.h"
21 #include "llvm/CodeGen/MachineFrameInfo.h"
22 #include "llvm/CodeGen/MachineFunctionPass.h"
23 #include "llvm/CodeGen/MachineInstr.h"
24 #include "llvm/CodeGen/MachineJumpTableInfo.h"
25 #include "llvm/CodeGen/MachineModuleInfo.h"
26 #include "llvm/CodeGen/MachineRegisterInfo.h"
27 #include "llvm/CodeGen/Passes.h"
28 #include "llvm/IR/DataLayout.h"
29 #include "llvm/IR/DebugInfo.h"
30 #include "llvm/IR/Function.h"
31 #include "llvm/MC/MCAsmInfo.h"
32 #include "llvm/MC/MCContext.h"
33 #include "llvm/Support/Debug.h"
34 #include "llvm/Support/GraphWriter.h"
35 #include "llvm/Support/raw_ostream.h"
36 #include "llvm/Target/TargetFrameLowering.h"
37 #include "llvm/Target/TargetLowering.h"
38 #include "llvm/Target/TargetMachine.h"
39 #include "llvm/Target/TargetSubtargetInfo.h"
40 using namespace llvm;
41
42 #define DEBUG_TYPE "codegen"
43
44 //===----------------------------------------------------------------------===//
45 // MachineFunction implementation
46 //===----------------------------------------------------------------------===//
47
48 // Out of line virtual method.
~MachineFunctionInfo()49 MachineFunctionInfo::~MachineFunctionInfo() {}
50
deleteNode(MachineBasicBlock * MBB)51 void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
52 MBB->getParent()->DeleteMachineBasicBlock(MBB);
53 }
54
MachineFunction(const Function * F,const TargetMachine & TM,unsigned FunctionNum,MachineModuleInfo & mmi)55 MachineFunction::MachineFunction(const Function *F, const TargetMachine &TM,
56 unsigned FunctionNum, MachineModuleInfo &mmi)
57 : Fn(F), Target(TM), STI(TM.getSubtargetImpl(*F)), Ctx(mmi.getContext()),
58 MMI(mmi) {
59 if (STI->getRegisterInfo())
60 RegInfo = new (Allocator) MachineRegisterInfo(this);
61 else
62 RegInfo = nullptr;
63
64 MFInfo = nullptr;
65 FrameInfo = new (Allocator)
66 MachineFrameInfo(STI->getFrameLowering()->getStackAlignment(),
67 STI->getFrameLowering()->isStackRealignable(),
68 !F->hasFnAttribute("no-realign-stack"));
69
70 if (Fn->hasFnAttribute(Attribute::StackAlignment))
71 FrameInfo->ensureMaxAlignment(Fn->getFnStackAlignment());
72
73 ConstantPool = new (Allocator) MachineConstantPool(TM);
74 Alignment = STI->getTargetLowering()->getMinFunctionAlignment();
75
76 // FIXME: Shouldn't use pref alignment if explicit alignment is set on Fn.
77 if (!Fn->hasFnAttribute(Attribute::OptimizeForSize))
78 Alignment = std::max(Alignment,
79 STI->getTargetLowering()->getPrefFunctionAlignment());
80
81 FunctionNumber = FunctionNum;
82 JumpTableInfo = nullptr;
83 }
84
~MachineFunction()85 MachineFunction::~MachineFunction() {
86 // Don't call destructors on MachineInstr and MachineOperand. All of their
87 // memory comes from the BumpPtrAllocator which is about to be purged.
88 //
89 // Do call MachineBasicBlock destructors, it contains std::vectors.
90 for (iterator I = begin(), E = end(); I != E; I = BasicBlocks.erase(I))
91 I->Insts.clearAndLeakNodesUnsafely();
92
93 InstructionRecycler.clear(Allocator);
94 OperandRecycler.clear(Allocator);
95 BasicBlockRecycler.clear(Allocator);
96 if (RegInfo) {
97 RegInfo->~MachineRegisterInfo();
98 Allocator.Deallocate(RegInfo);
99 }
100 if (MFInfo) {
101 MFInfo->~MachineFunctionInfo();
102 Allocator.Deallocate(MFInfo);
103 }
104
105 FrameInfo->~MachineFrameInfo();
106 Allocator.Deallocate(FrameInfo);
107
108 ConstantPool->~MachineConstantPool();
109 Allocator.Deallocate(ConstantPool);
110
111 if (JumpTableInfo) {
112 JumpTableInfo->~MachineJumpTableInfo();
113 Allocator.Deallocate(JumpTableInfo);
114 }
115 }
116
117 /// getOrCreateJumpTableInfo - Get the JumpTableInfo for this function, if it
118 /// does already exist, allocate one.
119 MachineJumpTableInfo *MachineFunction::
getOrCreateJumpTableInfo(unsigned EntryKind)120 getOrCreateJumpTableInfo(unsigned EntryKind) {
121 if (JumpTableInfo) return JumpTableInfo;
122
123 JumpTableInfo = new (Allocator)
124 MachineJumpTableInfo((MachineJumpTableInfo::JTEntryKind)EntryKind);
125 return JumpTableInfo;
126 }
127
128 /// Should we be emitting segmented stack stuff for the function
shouldSplitStack()129 bool MachineFunction::shouldSplitStack() {
130 return getFunction()->hasFnAttribute("split-stack");
131 }
132
133 /// RenumberBlocks - This discards all of the MachineBasicBlock numbers and
134 /// recomputes them. This guarantees that the MBB numbers are sequential,
135 /// dense, and match the ordering of the blocks within the function. If a
136 /// specific MachineBasicBlock is specified, only that block and those after
137 /// it are renumbered.
RenumberBlocks(MachineBasicBlock * MBB)138 void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
139 if (empty()) { MBBNumbering.clear(); return; }
140 MachineFunction::iterator MBBI, E = end();
141 if (MBB == nullptr)
142 MBBI = begin();
143 else
144 MBBI = MBB;
145
146 // Figure out the block number this should have.
147 unsigned BlockNo = 0;
148 if (MBBI != begin())
149 BlockNo = std::prev(MBBI)->getNumber() + 1;
150
151 for (; MBBI != E; ++MBBI, ++BlockNo) {
152 if (MBBI->getNumber() != (int)BlockNo) {
153 // Remove use of the old number.
154 if (MBBI->getNumber() != -1) {
155 assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
156 "MBB number mismatch!");
157 MBBNumbering[MBBI->getNumber()] = nullptr;
158 }
159
160 // If BlockNo is already taken, set that block's number to -1.
161 if (MBBNumbering[BlockNo])
162 MBBNumbering[BlockNo]->setNumber(-1);
163
164 MBBNumbering[BlockNo] = MBBI;
165 MBBI->setNumber(BlockNo);
166 }
167 }
168
169 // Okay, all the blocks are renumbered. If we have compactified the block
170 // numbering, shrink MBBNumbering now.
171 assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
172 MBBNumbering.resize(BlockNo);
173 }
174
175 /// CreateMachineInstr - Allocate a new MachineInstr. Use this instead
176 /// of `new MachineInstr'.
177 ///
178 MachineInstr *
CreateMachineInstr(const MCInstrDesc & MCID,DebugLoc DL,bool NoImp)179 MachineFunction::CreateMachineInstr(const MCInstrDesc &MCID,
180 DebugLoc DL, bool NoImp) {
181 return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
182 MachineInstr(*this, MCID, DL, NoImp);
183 }
184
185 /// CloneMachineInstr - Create a new MachineInstr which is a copy of the
186 /// 'Orig' instruction, identical in all ways except the instruction
187 /// has no parent, prev, or next.
188 ///
189 MachineInstr *
CloneMachineInstr(const MachineInstr * Orig)190 MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
191 return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
192 MachineInstr(*this, *Orig);
193 }
194
195 /// DeleteMachineInstr - Delete the given MachineInstr.
196 ///
197 /// This function also serves as the MachineInstr destructor - the real
198 /// ~MachineInstr() destructor must be empty.
199 void
DeleteMachineInstr(MachineInstr * MI)200 MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
201 // Strip it for parts. The operand array and the MI object itself are
202 // independently recyclable.
203 if (MI->Operands)
204 deallocateOperandArray(MI->CapOperands, MI->Operands);
205 // Don't call ~MachineInstr() which must be trivial anyway because
206 // ~MachineFunction drops whole lists of MachineInstrs wihout calling their
207 // destructors.
208 InstructionRecycler.Deallocate(Allocator, MI);
209 }
210
211 /// CreateMachineBasicBlock - Allocate a new MachineBasicBlock. Use this
212 /// instead of `new MachineBasicBlock'.
213 ///
214 MachineBasicBlock *
CreateMachineBasicBlock(const BasicBlock * bb)215 MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
216 return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
217 MachineBasicBlock(*this, bb);
218 }
219
220 /// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
221 ///
222 void
DeleteMachineBasicBlock(MachineBasicBlock * MBB)223 MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
224 assert(MBB->getParent() == this && "MBB parent mismatch!");
225 MBB->~MachineBasicBlock();
226 BasicBlockRecycler.Deallocate(Allocator, MBB);
227 }
228
229 MachineMemOperand *
getMachineMemOperand(MachinePointerInfo PtrInfo,unsigned f,uint64_t s,unsigned base_alignment,const AAMDNodes & AAInfo,const MDNode * Ranges)230 MachineFunction::getMachineMemOperand(MachinePointerInfo PtrInfo, unsigned f,
231 uint64_t s, unsigned base_alignment,
232 const AAMDNodes &AAInfo,
233 const MDNode *Ranges) {
234 return new (Allocator) MachineMemOperand(PtrInfo, f, s, base_alignment,
235 AAInfo, Ranges);
236 }
237
238 MachineMemOperand *
getMachineMemOperand(const MachineMemOperand * MMO,int64_t Offset,uint64_t Size)239 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
240 int64_t Offset, uint64_t Size) {
241 if (MMO->getValue())
242 return new (Allocator)
243 MachineMemOperand(MachinePointerInfo(MMO->getValue(),
244 MMO->getOffset()+Offset),
245 MMO->getFlags(), Size,
246 MMO->getBaseAlignment());
247 return new (Allocator)
248 MachineMemOperand(MachinePointerInfo(MMO->getPseudoValue(),
249 MMO->getOffset()+Offset),
250 MMO->getFlags(), Size,
251 MMO->getBaseAlignment());
252 }
253
254 MachineInstr::mmo_iterator
allocateMemRefsArray(unsigned long Num)255 MachineFunction::allocateMemRefsArray(unsigned long Num) {
256 return Allocator.Allocate<MachineMemOperand *>(Num);
257 }
258
259 std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
extractLoadMemRefs(MachineInstr::mmo_iterator Begin,MachineInstr::mmo_iterator End)260 MachineFunction::extractLoadMemRefs(MachineInstr::mmo_iterator Begin,
261 MachineInstr::mmo_iterator End) {
262 // Count the number of load mem refs.
263 unsigned Num = 0;
264 for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
265 if ((*I)->isLoad())
266 ++Num;
267
268 // Allocate a new array and populate it with the load information.
269 MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
270 unsigned Index = 0;
271 for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
272 if ((*I)->isLoad()) {
273 if (!(*I)->isStore())
274 // Reuse the MMO.
275 Result[Index] = *I;
276 else {
277 // Clone the MMO and unset the store flag.
278 MachineMemOperand *JustLoad =
279 getMachineMemOperand((*I)->getPointerInfo(),
280 (*I)->getFlags() & ~MachineMemOperand::MOStore,
281 (*I)->getSize(), (*I)->getBaseAlignment(),
282 (*I)->getAAInfo());
283 Result[Index] = JustLoad;
284 }
285 ++Index;
286 }
287 }
288 return std::make_pair(Result, Result + Num);
289 }
290
291 std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
extractStoreMemRefs(MachineInstr::mmo_iterator Begin,MachineInstr::mmo_iterator End)292 MachineFunction::extractStoreMemRefs(MachineInstr::mmo_iterator Begin,
293 MachineInstr::mmo_iterator End) {
294 // Count the number of load mem refs.
295 unsigned Num = 0;
296 for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
297 if ((*I)->isStore())
298 ++Num;
299
300 // Allocate a new array and populate it with the store information.
301 MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
302 unsigned Index = 0;
303 for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
304 if ((*I)->isStore()) {
305 if (!(*I)->isLoad())
306 // Reuse the MMO.
307 Result[Index] = *I;
308 else {
309 // Clone the MMO and unset the load flag.
310 MachineMemOperand *JustStore =
311 getMachineMemOperand((*I)->getPointerInfo(),
312 (*I)->getFlags() & ~MachineMemOperand::MOLoad,
313 (*I)->getSize(), (*I)->getBaseAlignment(),
314 (*I)->getAAInfo());
315 Result[Index] = JustStore;
316 }
317 ++Index;
318 }
319 }
320 return std::make_pair(Result, Result + Num);
321 }
322
323 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump() const324 void MachineFunction::dump() const {
325 print(dbgs());
326 }
327 #endif
328
getName() const329 StringRef MachineFunction::getName() const {
330 assert(getFunction() && "No function!");
331 return getFunction()->getName();
332 }
333
print(raw_ostream & OS,SlotIndexes * Indexes) const334 void MachineFunction::print(raw_ostream &OS, SlotIndexes *Indexes) const {
335 OS << "# Machine code for function " << getName() << ": ";
336 if (RegInfo) {
337 OS << (RegInfo->isSSA() ? "SSA" : "Post SSA");
338 if (!RegInfo->tracksLiveness())
339 OS << ", not tracking liveness";
340 }
341 OS << '\n';
342
343 // Print Frame Information
344 FrameInfo->print(*this, OS);
345
346 // Print JumpTable Information
347 if (JumpTableInfo)
348 JumpTableInfo->print(OS);
349
350 // Print Constant Pool
351 ConstantPool->print(OS);
352
353 const TargetRegisterInfo *TRI = getSubtarget().getRegisterInfo();
354
355 if (RegInfo && !RegInfo->livein_empty()) {
356 OS << "Function Live Ins: ";
357 for (MachineRegisterInfo::livein_iterator
358 I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
359 OS << PrintReg(I->first, TRI);
360 if (I->second)
361 OS << " in " << PrintReg(I->second, TRI);
362 if (std::next(I) != E)
363 OS << ", ";
364 }
365 OS << '\n';
366 }
367
368 for (const auto &BB : *this) {
369 OS << '\n';
370 BB.print(OS, Indexes);
371 }
372
373 OS << "\n# End machine code for function " << getName() << ".\n\n";
374 }
375
376 namespace llvm {
377 template<>
378 struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
379
DOTGraphTraitsllvm::DOTGraphTraits380 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {}
381
getGraphNamellvm::DOTGraphTraits382 static std::string getGraphName(const MachineFunction *F) {
383 return ("CFG for '" + F->getName() + "' function").str();
384 }
385
getNodeLabelllvm::DOTGraphTraits386 std::string getNodeLabel(const MachineBasicBlock *Node,
387 const MachineFunction *Graph) {
388 std::string OutStr;
389 {
390 raw_string_ostream OSS(OutStr);
391
392 if (isSimple()) {
393 OSS << "BB#" << Node->getNumber();
394 if (const BasicBlock *BB = Node->getBasicBlock())
395 OSS << ": " << BB->getName();
396 } else
397 Node->print(OSS);
398 }
399
400 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
401
402 // Process string output to make it nicer...
403 for (unsigned i = 0; i != OutStr.length(); ++i)
404 if (OutStr[i] == '\n') { // Left justify
405 OutStr[i] = '\\';
406 OutStr.insert(OutStr.begin()+i+1, 'l');
407 }
408 return OutStr;
409 }
410 };
411 }
412
viewCFG() const413 void MachineFunction::viewCFG() const
414 {
415 #ifndef NDEBUG
416 ViewGraph(this, "mf" + getName());
417 #else
418 errs() << "MachineFunction::viewCFG is only available in debug builds on "
419 << "systems with Graphviz or gv!\n";
420 #endif // NDEBUG
421 }
422
viewCFGOnly() const423 void MachineFunction::viewCFGOnly() const
424 {
425 #ifndef NDEBUG
426 ViewGraph(this, "mf" + getName(), true);
427 #else
428 errs() << "MachineFunction::viewCFGOnly is only available in debug builds on "
429 << "systems with Graphviz or gv!\n";
430 #endif // NDEBUG
431 }
432
433 /// addLiveIn - Add the specified physical register as a live-in value and
434 /// create a corresponding virtual register for it.
addLiveIn(unsigned PReg,const TargetRegisterClass * RC)435 unsigned MachineFunction::addLiveIn(unsigned PReg,
436 const TargetRegisterClass *RC) {
437 MachineRegisterInfo &MRI = getRegInfo();
438 unsigned VReg = MRI.getLiveInVirtReg(PReg);
439 if (VReg) {
440 const TargetRegisterClass *VRegRC = MRI.getRegClass(VReg);
441 (void)VRegRC;
442 // A physical register can be added several times.
443 // Between two calls, the register class of the related virtual register
444 // may have been constrained to match some operation constraints.
445 // In that case, check that the current register class includes the
446 // physical register and is a sub class of the specified RC.
447 assert((VRegRC == RC || (VRegRC->contains(PReg) &&
448 RC->hasSubClassEq(VRegRC))) &&
449 "Register class mismatch!");
450 return VReg;
451 }
452 VReg = MRI.createVirtualRegister(RC);
453 MRI.addLiveIn(PReg, VReg);
454 return VReg;
455 }
456
457 /// getJTISymbol - Return the MCSymbol for the specified non-empty jump table.
458 /// If isLinkerPrivate is specified, an 'l' label is returned, otherwise a
459 /// normal 'L' label is returned.
getJTISymbol(unsigned JTI,MCContext & Ctx,bool isLinkerPrivate) const460 MCSymbol *MachineFunction::getJTISymbol(unsigned JTI, MCContext &Ctx,
461 bool isLinkerPrivate) const {
462 const DataLayout *DL = getTarget().getDataLayout();
463 assert(JumpTableInfo && "No jump tables");
464 assert(JTI < JumpTableInfo->getJumpTables().size() && "Invalid JTI!");
465
466 const char *Prefix = isLinkerPrivate ? DL->getLinkerPrivateGlobalPrefix() :
467 DL->getPrivateGlobalPrefix();
468 SmallString<60> Name;
469 raw_svector_ostream(Name)
470 << Prefix << "JTI" << getFunctionNumber() << '_' << JTI;
471 return Ctx.GetOrCreateSymbol(Name);
472 }
473
474 /// getPICBaseSymbol - Return a function-local symbol to represent the PIC
475 /// base.
getPICBaseSymbol() const476 MCSymbol *MachineFunction::getPICBaseSymbol() const {
477 const DataLayout *DL = getTarget().getDataLayout();
478 return Ctx.GetOrCreateSymbol(Twine(DL->getPrivateGlobalPrefix())+
479 Twine(getFunctionNumber())+"$pb");
480 }
481
482 //===----------------------------------------------------------------------===//
483 // MachineFrameInfo implementation
484 //===----------------------------------------------------------------------===//
485
486 /// ensureMaxAlignment - Make sure the function is at least Align bytes
487 /// aligned.
ensureMaxAlignment(unsigned Align)488 void MachineFrameInfo::ensureMaxAlignment(unsigned Align) {
489 if (!StackRealignable || !RealignOption)
490 assert(Align <= StackAlignment &&
491 "For targets without stack realignment, Align is out of limit!");
492 if (MaxAlignment < Align) MaxAlignment = Align;
493 }
494
495 /// clampStackAlignment - Clamp the alignment if requested and emit a warning.
clampStackAlignment(bool ShouldClamp,unsigned Align,unsigned StackAlign)496 static inline unsigned clampStackAlignment(bool ShouldClamp, unsigned Align,
497 unsigned StackAlign) {
498 if (!ShouldClamp || Align <= StackAlign)
499 return Align;
500 DEBUG(dbgs() << "Warning: requested alignment " << Align
501 << " exceeds the stack alignment " << StackAlign
502 << " when stack realignment is off" << '\n');
503 return StackAlign;
504 }
505
506 /// CreateStackObject - Create a new statically sized stack object, returning
507 /// a nonnegative identifier to represent it.
508 ///
CreateStackObject(uint64_t Size,unsigned Alignment,bool isSS,const AllocaInst * Alloca)509 int MachineFrameInfo::CreateStackObject(uint64_t Size, unsigned Alignment,
510 bool isSS, const AllocaInst *Alloca) {
511 assert(Size != 0 && "Cannot allocate zero size stack objects!");
512 Alignment = clampStackAlignment(!StackRealignable || !RealignOption,
513 Alignment, StackAlignment);
514 Objects.push_back(StackObject(Size, Alignment, 0, false, isSS, Alloca,
515 !isSS));
516 int Index = (int)Objects.size() - NumFixedObjects - 1;
517 assert(Index >= 0 && "Bad frame index!");
518 ensureMaxAlignment(Alignment);
519 return Index;
520 }
521
522 /// CreateSpillStackObject - Create a new statically sized stack object that
523 /// represents a spill slot, returning a nonnegative identifier to represent
524 /// it.
525 ///
CreateSpillStackObject(uint64_t Size,unsigned Alignment)526 int MachineFrameInfo::CreateSpillStackObject(uint64_t Size,
527 unsigned Alignment) {
528 Alignment = clampStackAlignment(!StackRealignable || !RealignOption,
529 Alignment, StackAlignment);
530 CreateStackObject(Size, Alignment, true);
531 int Index = (int)Objects.size() - NumFixedObjects - 1;
532 ensureMaxAlignment(Alignment);
533 return Index;
534 }
535
536 /// CreateVariableSizedObject - Notify the MachineFrameInfo object that a
537 /// variable sized object has been created. This must be created whenever a
538 /// variable sized object is created, whether or not the index returned is
539 /// actually used.
540 ///
CreateVariableSizedObject(unsigned Alignment,const AllocaInst * Alloca)541 int MachineFrameInfo::CreateVariableSizedObject(unsigned Alignment,
542 const AllocaInst *Alloca) {
543 HasVarSizedObjects = true;
544 Alignment = clampStackAlignment(!StackRealignable || !RealignOption,
545 Alignment, StackAlignment);
546 Objects.push_back(StackObject(0, Alignment, 0, false, false, Alloca, true));
547 ensureMaxAlignment(Alignment);
548 return (int)Objects.size()-NumFixedObjects-1;
549 }
550
551 /// CreateFixedObject - Create a new object at a fixed location on the stack.
552 /// All fixed objects should be created before other objects are created for
553 /// efficiency. By default, fixed objects are immutable. This returns an
554 /// index with a negative value.
555 ///
CreateFixedObject(uint64_t Size,int64_t SPOffset,bool Immutable,bool isAliased)556 int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
557 bool Immutable, bool isAliased) {
558 assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
559 // The alignment of the frame index can be determined from its offset from
560 // the incoming frame position. If the frame object is at offset 32 and
561 // the stack is guaranteed to be 16-byte aligned, then we know that the
562 // object is 16-byte aligned.
563 unsigned Align = MinAlign(SPOffset, StackAlignment);
564 Align = clampStackAlignment(!StackRealignable || !RealignOption, Align,
565 StackAlignment);
566 Objects.insert(Objects.begin(), StackObject(Size, Align, SPOffset, Immutable,
567 /*isSS*/ false,
568 /*Alloca*/ nullptr, isAliased));
569 return -++NumFixedObjects;
570 }
571
572 /// CreateFixedSpillStackObject - Create a spill slot at a fixed location
573 /// on the stack. Returns an index with a negative value.
CreateFixedSpillStackObject(uint64_t Size,int64_t SPOffset)574 int MachineFrameInfo::CreateFixedSpillStackObject(uint64_t Size,
575 int64_t SPOffset) {
576 unsigned Align = MinAlign(SPOffset, StackAlignment);
577 Align = clampStackAlignment(!StackRealignable || !RealignOption, Align,
578 StackAlignment);
579 Objects.insert(Objects.begin(), StackObject(Size, Align, SPOffset,
580 /*Immutable*/ true,
581 /*isSS*/ true,
582 /*Alloca*/ nullptr,
583 /*isAliased*/ false));
584 return -++NumFixedObjects;
585 }
586
587 BitVector
getPristineRegs(const MachineBasicBlock * MBB) const588 MachineFrameInfo::getPristineRegs(const MachineBasicBlock *MBB) const {
589 assert(MBB && "MBB must be valid");
590 const MachineFunction *MF = MBB->getParent();
591 assert(MF && "MBB must be part of a MachineFunction");
592 const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
593 BitVector BV(TRI->getNumRegs());
594
595 // Before CSI is calculated, no registers are considered pristine. They can be
596 // freely used and PEI will make sure they are saved.
597 if (!isCalleeSavedInfoValid())
598 return BV;
599
600 for (const MCPhysReg *CSR = TRI->getCalleeSavedRegs(MF); CSR && *CSR; ++CSR)
601 BV.set(*CSR);
602
603 // The entry MBB always has all CSRs pristine.
604 if (MBB == &MF->front())
605 return BV;
606
607 // On other MBBs the saved CSRs are not pristine.
608 const std::vector<CalleeSavedInfo> &CSI = getCalleeSavedInfo();
609 for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
610 E = CSI.end(); I != E; ++I)
611 BV.reset(I->getReg());
612
613 return BV;
614 }
615
estimateStackSize(const MachineFunction & MF) const616 unsigned MachineFrameInfo::estimateStackSize(const MachineFunction &MF) const {
617 const TargetFrameLowering *TFI = MF.getSubtarget().getFrameLowering();
618 const TargetRegisterInfo *RegInfo = MF.getSubtarget().getRegisterInfo();
619 unsigned MaxAlign = getMaxAlignment();
620 int Offset = 0;
621
622 // This code is very, very similar to PEI::calculateFrameObjectOffsets().
623 // It really should be refactored to share code. Until then, changes
624 // should keep in mind that there's tight coupling between the two.
625
626 for (int i = getObjectIndexBegin(); i != 0; ++i) {
627 int FixedOff = -getObjectOffset(i);
628 if (FixedOff > Offset) Offset = FixedOff;
629 }
630 for (unsigned i = 0, e = getObjectIndexEnd(); i != e; ++i) {
631 if (isDeadObjectIndex(i))
632 continue;
633 Offset += getObjectSize(i);
634 unsigned Align = getObjectAlignment(i);
635 // Adjust to alignment boundary
636 Offset = (Offset+Align-1)/Align*Align;
637
638 MaxAlign = std::max(Align, MaxAlign);
639 }
640
641 if (adjustsStack() && TFI->hasReservedCallFrame(MF))
642 Offset += getMaxCallFrameSize();
643
644 // Round up the size to a multiple of the alignment. If the function has
645 // any calls or alloca's, align to the target's StackAlignment value to
646 // ensure that the callee's frame or the alloca data is suitably aligned;
647 // otherwise, for leaf functions, align to the TransientStackAlignment
648 // value.
649 unsigned StackAlign;
650 if (adjustsStack() || hasVarSizedObjects() ||
651 (RegInfo->needsStackRealignment(MF) && getObjectIndexEnd() != 0))
652 StackAlign = TFI->getStackAlignment();
653 else
654 StackAlign = TFI->getTransientStackAlignment();
655
656 // If the frame pointer is eliminated, all frame offsets will be relative to
657 // SP not FP. Align to MaxAlign so this works.
658 StackAlign = std::max(StackAlign, MaxAlign);
659 unsigned AlignMask = StackAlign - 1;
660 Offset = (Offset + AlignMask) & ~uint64_t(AlignMask);
661
662 return (unsigned)Offset;
663 }
664
print(const MachineFunction & MF,raw_ostream & OS) const665 void MachineFrameInfo::print(const MachineFunction &MF, raw_ostream &OS) const{
666 if (Objects.empty()) return;
667
668 const TargetFrameLowering *FI = MF.getSubtarget().getFrameLowering();
669 int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
670
671 OS << "Frame Objects:\n";
672
673 for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
674 const StackObject &SO = Objects[i];
675 OS << " fi#" << (int)(i-NumFixedObjects) << ": ";
676 if (SO.Size == ~0ULL) {
677 OS << "dead\n";
678 continue;
679 }
680 if (SO.Size == 0)
681 OS << "variable sized";
682 else
683 OS << "size=" << SO.Size;
684 OS << ", align=" << SO.Alignment;
685
686 if (i < NumFixedObjects)
687 OS << ", fixed";
688 if (i < NumFixedObjects || SO.SPOffset != -1) {
689 int64_t Off = SO.SPOffset - ValOffset;
690 OS << ", at location [SP";
691 if (Off > 0)
692 OS << "+" << Off;
693 else if (Off < 0)
694 OS << Off;
695 OS << "]";
696 }
697 OS << "\n";
698 }
699 }
700
701 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump(const MachineFunction & MF) const702 void MachineFrameInfo::dump(const MachineFunction &MF) const {
703 print(MF, dbgs());
704 }
705 #endif
706
707 //===----------------------------------------------------------------------===//
708 // MachineJumpTableInfo implementation
709 //===----------------------------------------------------------------------===//
710
711 /// getEntrySize - Return the size of each entry in the jump table.
getEntrySize(const DataLayout & TD) const712 unsigned MachineJumpTableInfo::getEntrySize(const DataLayout &TD) const {
713 // The size of a jump table entry is 4 bytes unless the entry is just the
714 // address of a block, in which case it is the pointer size.
715 switch (getEntryKind()) {
716 case MachineJumpTableInfo::EK_BlockAddress:
717 return TD.getPointerSize();
718 case MachineJumpTableInfo::EK_GPRel64BlockAddress:
719 return 8;
720 case MachineJumpTableInfo::EK_GPRel32BlockAddress:
721 case MachineJumpTableInfo::EK_LabelDifference32:
722 case MachineJumpTableInfo::EK_Custom32:
723 return 4;
724 case MachineJumpTableInfo::EK_Inline:
725 return 0;
726 }
727 llvm_unreachable("Unknown jump table encoding!");
728 }
729
730 /// getEntryAlignment - Return the alignment of each entry in the jump table.
getEntryAlignment(const DataLayout & TD) const731 unsigned MachineJumpTableInfo::getEntryAlignment(const DataLayout &TD) const {
732 // The alignment of a jump table entry is the alignment of int32 unless the
733 // entry is just the address of a block, in which case it is the pointer
734 // alignment.
735 switch (getEntryKind()) {
736 case MachineJumpTableInfo::EK_BlockAddress:
737 return TD.getPointerABIAlignment();
738 case MachineJumpTableInfo::EK_GPRel64BlockAddress:
739 return TD.getABIIntegerTypeAlignment(64);
740 case MachineJumpTableInfo::EK_GPRel32BlockAddress:
741 case MachineJumpTableInfo::EK_LabelDifference32:
742 case MachineJumpTableInfo::EK_Custom32:
743 return TD.getABIIntegerTypeAlignment(32);
744 case MachineJumpTableInfo::EK_Inline:
745 return 1;
746 }
747 llvm_unreachable("Unknown jump table encoding!");
748 }
749
750 /// createJumpTableIndex - Create a new jump table entry in the jump table info.
751 ///
createJumpTableIndex(const std::vector<MachineBasicBlock * > & DestBBs)752 unsigned MachineJumpTableInfo::createJumpTableIndex(
753 const std::vector<MachineBasicBlock*> &DestBBs) {
754 assert(!DestBBs.empty() && "Cannot create an empty jump table!");
755 JumpTables.push_back(MachineJumpTableEntry(DestBBs));
756 return JumpTables.size()-1;
757 }
758
759 /// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
760 /// the jump tables to branch to New instead.
ReplaceMBBInJumpTables(MachineBasicBlock * Old,MachineBasicBlock * New)761 bool MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
762 MachineBasicBlock *New) {
763 assert(Old != New && "Not making a change?");
764 bool MadeChange = false;
765 for (size_t i = 0, e = JumpTables.size(); i != e; ++i)
766 ReplaceMBBInJumpTable(i, Old, New);
767 return MadeChange;
768 }
769
770 /// ReplaceMBBInJumpTable - If Old is a target of the jump tables, update
771 /// the jump table to branch to New instead.
ReplaceMBBInJumpTable(unsigned Idx,MachineBasicBlock * Old,MachineBasicBlock * New)772 bool MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx,
773 MachineBasicBlock *Old,
774 MachineBasicBlock *New) {
775 assert(Old != New && "Not making a change?");
776 bool MadeChange = false;
777 MachineJumpTableEntry &JTE = JumpTables[Idx];
778 for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
779 if (JTE.MBBs[j] == Old) {
780 JTE.MBBs[j] = New;
781 MadeChange = true;
782 }
783 return MadeChange;
784 }
785
print(raw_ostream & OS) const786 void MachineJumpTableInfo::print(raw_ostream &OS) const {
787 if (JumpTables.empty()) return;
788
789 OS << "Jump Tables:\n";
790
791 for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
792 OS << " jt#" << i << ": ";
793 for (unsigned j = 0, f = JumpTables[i].MBBs.size(); j != f; ++j)
794 OS << " BB#" << JumpTables[i].MBBs[j]->getNumber();
795 }
796
797 OS << '\n';
798 }
799
800 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump() const801 void MachineJumpTableInfo::dump() const { print(dbgs()); }
802 #endif
803
804
805 //===----------------------------------------------------------------------===//
806 // MachineConstantPool implementation
807 //===----------------------------------------------------------------------===//
808
anchor()809 void MachineConstantPoolValue::anchor() { }
810
getDataLayout() const811 const DataLayout *MachineConstantPool::getDataLayout() const {
812 return TM.getDataLayout();
813 }
814
getType() const815 Type *MachineConstantPoolEntry::getType() const {
816 if (isMachineConstantPoolEntry())
817 return Val.MachineCPVal->getType();
818 return Val.ConstVal->getType();
819 }
820
821
getRelocationInfo() const822 unsigned MachineConstantPoolEntry::getRelocationInfo() const {
823 if (isMachineConstantPoolEntry())
824 return Val.MachineCPVal->getRelocationInfo();
825 return Val.ConstVal->getRelocationInfo();
826 }
827
828 SectionKind
getSectionKind(const DataLayout * DL) const829 MachineConstantPoolEntry::getSectionKind(const DataLayout *DL) const {
830 SectionKind Kind;
831 switch (getRelocationInfo()) {
832 default:
833 llvm_unreachable("Unknown section kind");
834 case Constant::GlobalRelocations:
835 Kind = SectionKind::getReadOnlyWithRel();
836 break;
837 case Constant::LocalRelocation:
838 Kind = SectionKind::getReadOnlyWithRelLocal();
839 break;
840 case Constant::NoRelocation:
841 switch (DL->getTypeAllocSize(getType())) {
842 case 4:
843 Kind = SectionKind::getMergeableConst4();
844 break;
845 case 8:
846 Kind = SectionKind::getMergeableConst8();
847 break;
848 case 16:
849 Kind = SectionKind::getMergeableConst16();
850 break;
851 default:
852 Kind = SectionKind::getReadOnly();
853 break;
854 }
855 }
856 return Kind;
857 }
858
~MachineConstantPool()859 MachineConstantPool::~MachineConstantPool() {
860 for (unsigned i = 0, e = Constants.size(); i != e; ++i)
861 if (Constants[i].isMachineConstantPoolEntry())
862 delete Constants[i].Val.MachineCPVal;
863 for (DenseSet<MachineConstantPoolValue*>::iterator I =
864 MachineCPVsSharingEntries.begin(), E = MachineCPVsSharingEntries.end();
865 I != E; ++I)
866 delete *I;
867 }
868
869 /// CanShareConstantPoolEntry - Test whether the given two constants
870 /// can be allocated the same constant pool entry.
CanShareConstantPoolEntry(const Constant * A,const Constant * B,const DataLayout * TD)871 static bool CanShareConstantPoolEntry(const Constant *A, const Constant *B,
872 const DataLayout *TD) {
873 // Handle the trivial case quickly.
874 if (A == B) return true;
875
876 // If they have the same type but weren't the same constant, quickly
877 // reject them.
878 if (A->getType() == B->getType()) return false;
879
880 // We can't handle structs or arrays.
881 if (isa<StructType>(A->getType()) || isa<ArrayType>(A->getType()) ||
882 isa<StructType>(B->getType()) || isa<ArrayType>(B->getType()))
883 return false;
884
885 // For now, only support constants with the same size.
886 uint64_t StoreSize = TD->getTypeStoreSize(A->getType());
887 if (StoreSize != TD->getTypeStoreSize(B->getType()) || StoreSize > 128)
888 return false;
889
890 Type *IntTy = IntegerType::get(A->getContext(), StoreSize*8);
891
892 // Try constant folding a bitcast of both instructions to an integer. If we
893 // get two identical ConstantInt's, then we are good to share them. We use
894 // the constant folding APIs to do this so that we get the benefit of
895 // DataLayout.
896 if (isa<PointerType>(A->getType()))
897 A = ConstantFoldInstOperands(Instruction::PtrToInt, IntTy,
898 const_cast<Constant *>(A), *TD);
899 else if (A->getType() != IntTy)
900 A = ConstantFoldInstOperands(Instruction::BitCast, IntTy,
901 const_cast<Constant *>(A), *TD);
902 if (isa<PointerType>(B->getType()))
903 B = ConstantFoldInstOperands(Instruction::PtrToInt, IntTy,
904 const_cast<Constant *>(B), *TD);
905 else if (B->getType() != IntTy)
906 B = ConstantFoldInstOperands(Instruction::BitCast, IntTy,
907 const_cast<Constant *>(B), *TD);
908
909 return A == B;
910 }
911
912 /// getConstantPoolIndex - Create a new entry in the constant pool or return
913 /// an existing one. User must specify the log2 of the minimum required
914 /// alignment for the object.
915 ///
getConstantPoolIndex(const Constant * C,unsigned Alignment)916 unsigned MachineConstantPool::getConstantPoolIndex(const Constant *C,
917 unsigned Alignment) {
918 assert(Alignment && "Alignment must be specified!");
919 if (Alignment > PoolAlignment) PoolAlignment = Alignment;
920
921 // Check to see if we already have this constant.
922 //
923 // FIXME, this could be made much more efficient for large constant pools.
924 for (unsigned i = 0, e = Constants.size(); i != e; ++i)
925 if (!Constants[i].isMachineConstantPoolEntry() &&
926 CanShareConstantPoolEntry(Constants[i].Val.ConstVal, C,
927 getDataLayout())) {
928 if ((unsigned)Constants[i].getAlignment() < Alignment)
929 Constants[i].Alignment = Alignment;
930 return i;
931 }
932
933 Constants.push_back(MachineConstantPoolEntry(C, Alignment));
934 return Constants.size()-1;
935 }
936
getConstantPoolIndex(MachineConstantPoolValue * V,unsigned Alignment)937 unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
938 unsigned Alignment) {
939 assert(Alignment && "Alignment must be specified!");
940 if (Alignment > PoolAlignment) PoolAlignment = Alignment;
941
942 // Check to see if we already have this constant.
943 //
944 // FIXME, this could be made much more efficient for large constant pools.
945 int Idx = V->getExistingMachineCPValue(this, Alignment);
946 if (Idx != -1) {
947 MachineCPVsSharingEntries.insert(V);
948 return (unsigned)Idx;
949 }
950
951 Constants.push_back(MachineConstantPoolEntry(V, Alignment));
952 return Constants.size()-1;
953 }
954
print(raw_ostream & OS) const955 void MachineConstantPool::print(raw_ostream &OS) const {
956 if (Constants.empty()) return;
957
958 OS << "Constant Pool:\n";
959 for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
960 OS << " cp#" << i << ": ";
961 if (Constants[i].isMachineConstantPoolEntry())
962 Constants[i].Val.MachineCPVal->print(OS);
963 else
964 Constants[i].Val.ConstVal->printAsOperand(OS, /*PrintType=*/false);
965 OS << ", align=" << Constants[i].getAlignment();
966 OS << "\n";
967 }
968 }
969
970 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump() const971 void MachineConstantPool::dump() const { print(dbgs()); }
972 #endif
973