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/DebugInfo.h"
29 #include "llvm/IR/DataLayout.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 using namespace llvm;
40
41 //===----------------------------------------------------------------------===//
42 // MachineFunction implementation
43 //===----------------------------------------------------------------------===//
44
45 // Out of line virtual method.
~MachineFunctionInfo()46 MachineFunctionInfo::~MachineFunctionInfo() {}
47
deleteNode(MachineBasicBlock * MBB)48 void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
49 MBB->getParent()->DeleteMachineBasicBlock(MBB);
50 }
51
MachineFunction(const Function * F,const TargetMachine & TM,unsigned FunctionNum,MachineModuleInfo & mmi,GCModuleInfo * gmi)52 MachineFunction::MachineFunction(const Function *F, const TargetMachine &TM,
53 unsigned FunctionNum, MachineModuleInfo &mmi,
54 GCModuleInfo* gmi)
55 : Fn(F), Target(TM), Ctx(mmi.getContext()), MMI(mmi), GMI(gmi) {
56 if (TM.getRegisterInfo())
57 RegInfo = new (Allocator) MachineRegisterInfo(*TM.getRegisterInfo());
58 else
59 RegInfo = 0;
60 MFInfo = 0;
61 FrameInfo = new (Allocator) MachineFrameInfo(*TM.getFrameLowering(),
62 TM.Options.RealignStack);
63 if (Fn->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
64 Attribute::StackAlignment))
65 FrameInfo->ensureMaxAlignment(Fn->getAttributes().
66 getStackAlignment(AttributeSet::FunctionIndex));
67 ConstantPool = new (Allocator) MachineConstantPool(TM.getDataLayout());
68 Alignment = TM.getTargetLowering()->getMinFunctionAlignment();
69 // FIXME: Shouldn't use pref alignment if explicit alignment is set on Fn.
70 if (!Fn->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
71 Attribute::OptimizeForSize))
72 Alignment = std::max(Alignment,
73 TM.getTargetLowering()->getPrefFunctionAlignment());
74 FunctionNumber = FunctionNum;
75 JumpTableInfo = 0;
76 }
77
~MachineFunction()78 MachineFunction::~MachineFunction() {
79 // Don't call destructors on MachineInstr and MachineOperand. All of their
80 // memory comes from the BumpPtrAllocator which is about to be purged.
81 //
82 // Do call MachineBasicBlock destructors, it contains std::vectors.
83 for (iterator I = begin(), E = end(); I != E; I = BasicBlocks.erase(I))
84 I->Insts.clearAndLeakNodesUnsafely();
85
86 InstructionRecycler.clear(Allocator);
87 OperandRecycler.clear(Allocator);
88 BasicBlockRecycler.clear(Allocator);
89 if (RegInfo) {
90 RegInfo->~MachineRegisterInfo();
91 Allocator.Deallocate(RegInfo);
92 }
93 if (MFInfo) {
94 MFInfo->~MachineFunctionInfo();
95 Allocator.Deallocate(MFInfo);
96 }
97
98 FrameInfo->~MachineFrameInfo();
99 Allocator.Deallocate(FrameInfo);
100
101 ConstantPool->~MachineConstantPool();
102 Allocator.Deallocate(ConstantPool);
103
104 if (JumpTableInfo) {
105 JumpTableInfo->~MachineJumpTableInfo();
106 Allocator.Deallocate(JumpTableInfo);
107 }
108 }
109
110 /// getOrCreateJumpTableInfo - Get the JumpTableInfo for this function, if it
111 /// does already exist, allocate one.
112 MachineJumpTableInfo *MachineFunction::
getOrCreateJumpTableInfo(unsigned EntryKind)113 getOrCreateJumpTableInfo(unsigned EntryKind) {
114 if (JumpTableInfo) return JumpTableInfo;
115
116 JumpTableInfo = new (Allocator)
117 MachineJumpTableInfo((MachineJumpTableInfo::JTEntryKind)EntryKind);
118 return JumpTableInfo;
119 }
120
121 /// RenumberBlocks - This discards all of the MachineBasicBlock numbers and
122 /// recomputes them. This guarantees that the MBB numbers are sequential,
123 /// dense, and match the ordering of the blocks within the function. If a
124 /// specific MachineBasicBlock is specified, only that block and those after
125 /// it are renumbered.
RenumberBlocks(MachineBasicBlock * MBB)126 void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
127 if (empty()) { MBBNumbering.clear(); return; }
128 MachineFunction::iterator MBBI, E = end();
129 if (MBB == 0)
130 MBBI = begin();
131 else
132 MBBI = MBB;
133
134 // Figure out the block number this should have.
135 unsigned BlockNo = 0;
136 if (MBBI != begin())
137 BlockNo = prior(MBBI)->getNumber()+1;
138
139 for (; MBBI != E; ++MBBI, ++BlockNo) {
140 if (MBBI->getNumber() != (int)BlockNo) {
141 // Remove use of the old number.
142 if (MBBI->getNumber() != -1) {
143 assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
144 "MBB number mismatch!");
145 MBBNumbering[MBBI->getNumber()] = 0;
146 }
147
148 // If BlockNo is already taken, set that block's number to -1.
149 if (MBBNumbering[BlockNo])
150 MBBNumbering[BlockNo]->setNumber(-1);
151
152 MBBNumbering[BlockNo] = MBBI;
153 MBBI->setNumber(BlockNo);
154 }
155 }
156
157 // Okay, all the blocks are renumbered. If we have compactified the block
158 // numbering, shrink MBBNumbering now.
159 assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
160 MBBNumbering.resize(BlockNo);
161 }
162
163 /// CreateMachineInstr - Allocate a new MachineInstr. Use this instead
164 /// of `new MachineInstr'.
165 ///
166 MachineInstr *
CreateMachineInstr(const MCInstrDesc & MCID,DebugLoc DL,bool NoImp)167 MachineFunction::CreateMachineInstr(const MCInstrDesc &MCID,
168 DebugLoc DL, bool NoImp) {
169 return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
170 MachineInstr(*this, MCID, DL, NoImp);
171 }
172
173 /// CloneMachineInstr - Create a new MachineInstr which is a copy of the
174 /// 'Orig' instruction, identical in all ways except the instruction
175 /// has no parent, prev, or next.
176 ///
177 MachineInstr *
CloneMachineInstr(const MachineInstr * Orig)178 MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
179 return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
180 MachineInstr(*this, *Orig);
181 }
182
183 /// DeleteMachineInstr - Delete the given MachineInstr.
184 ///
185 /// This function also serves as the MachineInstr destructor - the real
186 /// ~MachineInstr() destructor must be empty.
187 void
DeleteMachineInstr(MachineInstr * MI)188 MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
189 // Strip it for parts. The operand array and the MI object itself are
190 // independently recyclable.
191 if (MI->Operands)
192 deallocateOperandArray(MI->CapOperands, MI->Operands);
193 // Don't call ~MachineInstr() which must be trivial anyway because
194 // ~MachineFunction drops whole lists of MachineInstrs wihout calling their
195 // destructors.
196 InstructionRecycler.Deallocate(Allocator, MI);
197 }
198
199 /// CreateMachineBasicBlock - Allocate a new MachineBasicBlock. Use this
200 /// instead of `new MachineBasicBlock'.
201 ///
202 MachineBasicBlock *
CreateMachineBasicBlock(const BasicBlock * bb)203 MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
204 return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
205 MachineBasicBlock(*this, bb);
206 }
207
208 /// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
209 ///
210 void
DeleteMachineBasicBlock(MachineBasicBlock * MBB)211 MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
212 assert(MBB->getParent() == this && "MBB parent mismatch!");
213 MBB->~MachineBasicBlock();
214 BasicBlockRecycler.Deallocate(Allocator, MBB);
215 }
216
217 MachineMemOperand *
getMachineMemOperand(MachinePointerInfo PtrInfo,unsigned f,uint64_t s,unsigned base_alignment,const MDNode * TBAAInfo,const MDNode * Ranges)218 MachineFunction::getMachineMemOperand(MachinePointerInfo PtrInfo, unsigned f,
219 uint64_t s, unsigned base_alignment,
220 const MDNode *TBAAInfo,
221 const MDNode *Ranges) {
222 return new (Allocator) MachineMemOperand(PtrInfo, f, s, base_alignment,
223 TBAAInfo, Ranges);
224 }
225
226 MachineMemOperand *
getMachineMemOperand(const MachineMemOperand * MMO,int64_t Offset,uint64_t Size)227 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
228 int64_t Offset, uint64_t Size) {
229 return new (Allocator)
230 MachineMemOperand(MachinePointerInfo(MMO->getValue(),
231 MMO->getOffset()+Offset),
232 MMO->getFlags(), Size,
233 MMO->getBaseAlignment(), 0);
234 }
235
236 MachineInstr::mmo_iterator
allocateMemRefsArray(unsigned long Num)237 MachineFunction::allocateMemRefsArray(unsigned long Num) {
238 return Allocator.Allocate<MachineMemOperand *>(Num);
239 }
240
241 std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
extractLoadMemRefs(MachineInstr::mmo_iterator Begin,MachineInstr::mmo_iterator End)242 MachineFunction::extractLoadMemRefs(MachineInstr::mmo_iterator Begin,
243 MachineInstr::mmo_iterator End) {
244 // Count the number of load mem refs.
245 unsigned Num = 0;
246 for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
247 if ((*I)->isLoad())
248 ++Num;
249
250 // Allocate a new array and populate it with the load information.
251 MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
252 unsigned Index = 0;
253 for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
254 if ((*I)->isLoad()) {
255 if (!(*I)->isStore())
256 // Reuse the MMO.
257 Result[Index] = *I;
258 else {
259 // Clone the MMO and unset the store flag.
260 MachineMemOperand *JustLoad =
261 getMachineMemOperand((*I)->getPointerInfo(),
262 (*I)->getFlags() & ~MachineMemOperand::MOStore,
263 (*I)->getSize(), (*I)->getBaseAlignment(),
264 (*I)->getTBAAInfo());
265 Result[Index] = JustLoad;
266 }
267 ++Index;
268 }
269 }
270 return std::make_pair(Result, Result + Num);
271 }
272
273 std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
extractStoreMemRefs(MachineInstr::mmo_iterator Begin,MachineInstr::mmo_iterator End)274 MachineFunction::extractStoreMemRefs(MachineInstr::mmo_iterator Begin,
275 MachineInstr::mmo_iterator End) {
276 // Count the number of load mem refs.
277 unsigned Num = 0;
278 for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
279 if ((*I)->isStore())
280 ++Num;
281
282 // Allocate a new array and populate it with the store information.
283 MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
284 unsigned Index = 0;
285 for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
286 if ((*I)->isStore()) {
287 if (!(*I)->isLoad())
288 // Reuse the MMO.
289 Result[Index] = *I;
290 else {
291 // Clone the MMO and unset the load flag.
292 MachineMemOperand *JustStore =
293 getMachineMemOperand((*I)->getPointerInfo(),
294 (*I)->getFlags() & ~MachineMemOperand::MOLoad,
295 (*I)->getSize(), (*I)->getBaseAlignment(),
296 (*I)->getTBAAInfo());
297 Result[Index] = JustStore;
298 }
299 ++Index;
300 }
301 }
302 return std::make_pair(Result, Result + Num);
303 }
304
305 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump() const306 void MachineFunction::dump() const {
307 print(dbgs());
308 }
309 #endif
310
getName() const311 StringRef MachineFunction::getName() const {
312 assert(getFunction() && "No function!");
313 return getFunction()->getName();
314 }
315
print(raw_ostream & OS,SlotIndexes * Indexes) const316 void MachineFunction::print(raw_ostream &OS, SlotIndexes *Indexes) const {
317 OS << "# Machine code for function " << getName() << ": ";
318 if (RegInfo) {
319 OS << (RegInfo->isSSA() ? "SSA" : "Post SSA");
320 if (!RegInfo->tracksLiveness())
321 OS << ", not tracking liveness";
322 }
323 OS << '\n';
324
325 // Print Frame Information
326 FrameInfo->print(*this, OS);
327
328 // Print JumpTable Information
329 if (JumpTableInfo)
330 JumpTableInfo->print(OS);
331
332 // Print Constant Pool
333 ConstantPool->print(OS);
334
335 const TargetRegisterInfo *TRI = getTarget().getRegisterInfo();
336
337 if (RegInfo && !RegInfo->livein_empty()) {
338 OS << "Function Live Ins: ";
339 for (MachineRegisterInfo::livein_iterator
340 I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
341 OS << PrintReg(I->first, TRI);
342 if (I->second)
343 OS << " in " << PrintReg(I->second, TRI);
344 if (llvm::next(I) != E)
345 OS << ", ";
346 }
347 OS << '\n';
348 }
349
350 for (const_iterator BB = begin(), E = end(); BB != E; ++BB) {
351 OS << '\n';
352 BB->print(OS, Indexes);
353 }
354
355 OS << "\n# End machine code for function " << getName() << ".\n\n";
356 }
357
358 namespace llvm {
359 template<>
360 struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
361
DOTGraphTraitsllvm::DOTGraphTraits362 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {}
363
getGraphNamellvm::DOTGraphTraits364 static std::string getGraphName(const MachineFunction *F) {
365 return "CFG for '" + F->getName().str() + "' function";
366 }
367
getNodeLabelllvm::DOTGraphTraits368 std::string getNodeLabel(const MachineBasicBlock *Node,
369 const MachineFunction *Graph) {
370 std::string OutStr;
371 {
372 raw_string_ostream OSS(OutStr);
373
374 if (isSimple()) {
375 OSS << "BB#" << Node->getNumber();
376 if (const BasicBlock *BB = Node->getBasicBlock())
377 OSS << ": " << BB->getName();
378 } else
379 Node->print(OSS);
380 }
381
382 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
383
384 // Process string output to make it nicer...
385 for (unsigned i = 0; i != OutStr.length(); ++i)
386 if (OutStr[i] == '\n') { // Left justify
387 OutStr[i] = '\\';
388 OutStr.insert(OutStr.begin()+i+1, 'l');
389 }
390 return OutStr;
391 }
392 };
393 }
394
viewCFG() const395 void MachineFunction::viewCFG() const
396 {
397 #ifndef NDEBUG
398 ViewGraph(this, "mf" + getName());
399 #else
400 errs() << "MachineFunction::viewCFG is only available in debug builds on "
401 << "systems with Graphviz or gv!\n";
402 #endif // NDEBUG
403 }
404
viewCFGOnly() const405 void MachineFunction::viewCFGOnly() const
406 {
407 #ifndef NDEBUG
408 ViewGraph(this, "mf" + getName(), true);
409 #else
410 errs() << "MachineFunction::viewCFGOnly is only available in debug builds on "
411 << "systems with Graphviz or gv!\n";
412 #endif // NDEBUG
413 }
414
415 /// addLiveIn - Add the specified physical register as a live-in value and
416 /// create a corresponding virtual register for it.
addLiveIn(unsigned PReg,const TargetRegisterClass * RC)417 unsigned MachineFunction::addLiveIn(unsigned PReg,
418 const TargetRegisterClass *RC) {
419 MachineRegisterInfo &MRI = getRegInfo();
420 unsigned VReg = MRI.getLiveInVirtReg(PReg);
421 if (VReg) {
422 assert(MRI.getRegClass(VReg) == RC && "Register class mismatch!");
423 return VReg;
424 }
425 VReg = MRI.createVirtualRegister(RC);
426 MRI.addLiveIn(PReg, VReg);
427 return VReg;
428 }
429
430 /// getJTISymbol - Return the MCSymbol for the specified non-empty jump table.
431 /// If isLinkerPrivate is specified, an 'l' label is returned, otherwise a
432 /// normal 'L' label is returned.
getJTISymbol(unsigned JTI,MCContext & Ctx,bool isLinkerPrivate) const433 MCSymbol *MachineFunction::getJTISymbol(unsigned JTI, MCContext &Ctx,
434 bool isLinkerPrivate) const {
435 assert(JumpTableInfo && "No jump tables");
436 assert(JTI < JumpTableInfo->getJumpTables().size() && "Invalid JTI!");
437 const MCAsmInfo &MAI = *getTarget().getMCAsmInfo();
438
439 const char *Prefix = isLinkerPrivate ? MAI.getLinkerPrivateGlobalPrefix() :
440 MAI.getPrivateGlobalPrefix();
441 SmallString<60> Name;
442 raw_svector_ostream(Name)
443 << Prefix << "JTI" << getFunctionNumber() << '_' << JTI;
444 return Ctx.GetOrCreateSymbol(Name.str());
445 }
446
447 /// getPICBaseSymbol - Return a function-local symbol to represent the PIC
448 /// base.
getPICBaseSymbol() const449 MCSymbol *MachineFunction::getPICBaseSymbol() const {
450 const MCAsmInfo &MAI = *Target.getMCAsmInfo();
451 return Ctx.GetOrCreateSymbol(Twine(MAI.getPrivateGlobalPrefix())+
452 Twine(getFunctionNumber())+"$pb");
453 }
454
455 //===----------------------------------------------------------------------===//
456 // MachineFrameInfo implementation
457 //===----------------------------------------------------------------------===//
458
459 /// ensureMaxAlignment - Make sure the function is at least Align bytes
460 /// aligned.
ensureMaxAlignment(unsigned Align)461 void MachineFrameInfo::ensureMaxAlignment(unsigned Align) {
462 if (!TFI.isStackRealignable() || !RealignOption)
463 assert(Align <= TFI.getStackAlignment() &&
464 "For targets without stack realignment, Align is out of limit!");
465 if (MaxAlignment < Align) MaxAlignment = Align;
466 }
467
468 /// clampStackAlignment - Clamp the alignment if requested and emit a warning.
clampStackAlignment(bool ShouldClamp,unsigned Align,unsigned StackAlign)469 static inline unsigned clampStackAlignment(bool ShouldClamp, unsigned Align,
470 unsigned StackAlign) {
471 if (!ShouldClamp || Align <= StackAlign)
472 return Align;
473 DEBUG(dbgs() << "Warning: requested alignment " << Align
474 << " exceeds the stack alignment " << StackAlign
475 << " when stack realignment is off" << '\n');
476 return StackAlign;
477 }
478
479 /// CreateStackObject - Create a new statically sized stack object, returning
480 /// a nonnegative identifier to represent it.
481 ///
CreateStackObject(uint64_t Size,unsigned Alignment,bool isSS,bool MayNeedSP,const AllocaInst * Alloca)482 int MachineFrameInfo::CreateStackObject(uint64_t Size, unsigned Alignment,
483 bool isSS, bool MayNeedSP, const AllocaInst *Alloca) {
484 assert(Size != 0 && "Cannot allocate zero size stack objects!");
485 Alignment = clampStackAlignment(!TFI.isStackRealignable() || !RealignOption,
486 Alignment, TFI.getStackAlignment());
487 Objects.push_back(StackObject(Size, Alignment, 0, false, isSS, MayNeedSP,
488 Alloca));
489 int Index = (int)Objects.size() - NumFixedObjects - 1;
490 assert(Index >= 0 && "Bad frame index!");
491 ensureMaxAlignment(Alignment);
492 return Index;
493 }
494
495 /// CreateSpillStackObject - Create a new statically sized stack object that
496 /// represents a spill slot, returning a nonnegative identifier to represent
497 /// it.
498 ///
CreateSpillStackObject(uint64_t Size,unsigned Alignment)499 int MachineFrameInfo::CreateSpillStackObject(uint64_t Size,
500 unsigned Alignment) {
501 Alignment = clampStackAlignment(!TFI.isStackRealignable() || !RealignOption,
502 Alignment, TFI.getStackAlignment());
503 CreateStackObject(Size, Alignment, true, false);
504 int Index = (int)Objects.size() - NumFixedObjects - 1;
505 ensureMaxAlignment(Alignment);
506 return Index;
507 }
508
509 /// CreateVariableSizedObject - Notify the MachineFrameInfo object that a
510 /// variable sized object has been created. This must be created whenever a
511 /// variable sized object is created, whether or not the index returned is
512 /// actually used.
513 ///
CreateVariableSizedObject(unsigned Alignment)514 int MachineFrameInfo::CreateVariableSizedObject(unsigned Alignment) {
515 HasVarSizedObjects = true;
516 Alignment = clampStackAlignment(!TFI.isStackRealignable() || !RealignOption,
517 Alignment, TFI.getStackAlignment());
518 Objects.push_back(StackObject(0, Alignment, 0, false, false, true, 0));
519 ensureMaxAlignment(Alignment);
520 return (int)Objects.size()-NumFixedObjects-1;
521 }
522
523 /// CreateFixedObject - Create a new object at a fixed location on the stack.
524 /// All fixed objects should be created before other objects are created for
525 /// efficiency. By default, fixed objects are immutable. This returns an
526 /// index with a negative value.
527 ///
CreateFixedObject(uint64_t Size,int64_t SPOffset,bool Immutable)528 int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
529 bool Immutable) {
530 assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
531 // The alignment of the frame index can be determined from its offset from
532 // the incoming frame position. If the frame object is at offset 32 and
533 // the stack is guaranteed to be 16-byte aligned, then we know that the
534 // object is 16-byte aligned.
535 unsigned StackAlign = TFI.getStackAlignment();
536 unsigned Align = MinAlign(SPOffset, StackAlign);
537 Align = clampStackAlignment(!TFI.isStackRealignable() || !RealignOption,
538 Align, TFI.getStackAlignment());
539 Objects.insert(Objects.begin(), StackObject(Size, Align, SPOffset, Immutable,
540 /*isSS*/ false,
541 /*NeedSP*/ false,
542 /*Alloca*/ 0));
543 return -++NumFixedObjects;
544 }
545
546
547 BitVector
getPristineRegs(const MachineBasicBlock * MBB) const548 MachineFrameInfo::getPristineRegs(const MachineBasicBlock *MBB) const {
549 assert(MBB && "MBB must be valid");
550 const MachineFunction *MF = MBB->getParent();
551 assert(MF && "MBB must be part of a MachineFunction");
552 const TargetMachine &TM = MF->getTarget();
553 const TargetRegisterInfo *TRI = TM.getRegisterInfo();
554 BitVector BV(TRI->getNumRegs());
555
556 // Before CSI is calculated, no registers are considered pristine. They can be
557 // freely used and PEI will make sure they are saved.
558 if (!isCalleeSavedInfoValid())
559 return BV;
560
561 for (const uint16_t *CSR = TRI->getCalleeSavedRegs(MF); CSR && *CSR; ++CSR)
562 BV.set(*CSR);
563
564 // The entry MBB always has all CSRs pristine.
565 if (MBB == &MF->front())
566 return BV;
567
568 // On other MBBs the saved CSRs are not pristine.
569 const std::vector<CalleeSavedInfo> &CSI = getCalleeSavedInfo();
570 for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
571 E = CSI.end(); I != E; ++I)
572 BV.reset(I->getReg());
573
574 return BV;
575 }
576
estimateStackSize(const MachineFunction & MF) const577 unsigned MachineFrameInfo::estimateStackSize(const MachineFunction &MF) const {
578 const TargetFrameLowering *TFI = MF.getTarget().getFrameLowering();
579 const TargetRegisterInfo *RegInfo = MF.getTarget().getRegisterInfo();
580 unsigned MaxAlign = getMaxAlignment();
581 int Offset = 0;
582
583 // This code is very, very similar to PEI::calculateFrameObjectOffsets().
584 // It really should be refactored to share code. Until then, changes
585 // should keep in mind that there's tight coupling between the two.
586
587 for (int i = getObjectIndexBegin(); i != 0; ++i) {
588 int FixedOff = -getObjectOffset(i);
589 if (FixedOff > Offset) Offset = FixedOff;
590 }
591 for (unsigned i = 0, e = getObjectIndexEnd(); i != e; ++i) {
592 if (isDeadObjectIndex(i))
593 continue;
594 Offset += getObjectSize(i);
595 unsigned Align = getObjectAlignment(i);
596 // Adjust to alignment boundary
597 Offset = (Offset+Align-1)/Align*Align;
598
599 MaxAlign = std::max(Align, MaxAlign);
600 }
601
602 if (adjustsStack() && TFI->hasReservedCallFrame(MF))
603 Offset += getMaxCallFrameSize();
604
605 // Round up the size to a multiple of the alignment. If the function has
606 // any calls or alloca's, align to the target's StackAlignment value to
607 // ensure that the callee's frame or the alloca data is suitably aligned;
608 // otherwise, for leaf functions, align to the TransientStackAlignment
609 // value.
610 unsigned StackAlign;
611 if (adjustsStack() || hasVarSizedObjects() ||
612 (RegInfo->needsStackRealignment(MF) && getObjectIndexEnd() != 0))
613 StackAlign = TFI->getStackAlignment();
614 else
615 StackAlign = TFI->getTransientStackAlignment();
616
617 // If the frame pointer is eliminated, all frame offsets will be relative to
618 // SP not FP. Align to MaxAlign so this works.
619 StackAlign = std::max(StackAlign, MaxAlign);
620 unsigned AlignMask = StackAlign - 1;
621 Offset = (Offset + AlignMask) & ~uint64_t(AlignMask);
622
623 return (unsigned)Offset;
624 }
625
print(const MachineFunction & MF,raw_ostream & OS) const626 void MachineFrameInfo::print(const MachineFunction &MF, raw_ostream &OS) const{
627 if (Objects.empty()) return;
628
629 const TargetFrameLowering *FI = MF.getTarget().getFrameLowering();
630 int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
631
632 OS << "Frame Objects:\n";
633
634 for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
635 const StackObject &SO = Objects[i];
636 OS << " fi#" << (int)(i-NumFixedObjects) << ": ";
637 if (SO.Size == ~0ULL) {
638 OS << "dead\n";
639 continue;
640 }
641 if (SO.Size == 0)
642 OS << "variable sized";
643 else
644 OS << "size=" << SO.Size;
645 OS << ", align=" << SO.Alignment;
646
647 if (i < NumFixedObjects)
648 OS << ", fixed";
649 if (i < NumFixedObjects || SO.SPOffset != -1) {
650 int64_t Off = SO.SPOffset - ValOffset;
651 OS << ", at location [SP";
652 if (Off > 0)
653 OS << "+" << Off;
654 else if (Off < 0)
655 OS << Off;
656 OS << "]";
657 }
658 OS << "\n";
659 }
660 }
661
662 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump(const MachineFunction & MF) const663 void MachineFrameInfo::dump(const MachineFunction &MF) const {
664 print(MF, dbgs());
665 }
666 #endif
667
668 //===----------------------------------------------------------------------===//
669 // MachineJumpTableInfo implementation
670 //===----------------------------------------------------------------------===//
671
672 /// getEntrySize - Return the size of each entry in the jump table.
getEntrySize(const DataLayout & TD) const673 unsigned MachineJumpTableInfo::getEntrySize(const DataLayout &TD) const {
674 // The size of a jump table entry is 4 bytes unless the entry is just the
675 // address of a block, in which case it is the pointer size.
676 switch (getEntryKind()) {
677 case MachineJumpTableInfo::EK_BlockAddress:
678 return TD.getPointerSize();
679 case MachineJumpTableInfo::EK_GPRel64BlockAddress:
680 return 8;
681 case MachineJumpTableInfo::EK_GPRel32BlockAddress:
682 case MachineJumpTableInfo::EK_LabelDifference32:
683 case MachineJumpTableInfo::EK_Custom32:
684 return 4;
685 case MachineJumpTableInfo::EK_Inline:
686 return 0;
687 }
688 llvm_unreachable("Unknown jump table encoding!");
689 }
690
691 /// getEntryAlignment - Return the alignment of each entry in the jump table.
getEntryAlignment(const DataLayout & TD) const692 unsigned MachineJumpTableInfo::getEntryAlignment(const DataLayout &TD) const {
693 // The alignment of a jump table entry is the alignment of int32 unless the
694 // entry is just the address of a block, in which case it is the pointer
695 // alignment.
696 switch (getEntryKind()) {
697 case MachineJumpTableInfo::EK_BlockAddress:
698 return TD.getPointerABIAlignment();
699 case MachineJumpTableInfo::EK_GPRel64BlockAddress:
700 return TD.getABIIntegerTypeAlignment(64);
701 case MachineJumpTableInfo::EK_GPRel32BlockAddress:
702 case MachineJumpTableInfo::EK_LabelDifference32:
703 case MachineJumpTableInfo::EK_Custom32:
704 return TD.getABIIntegerTypeAlignment(32);
705 case MachineJumpTableInfo::EK_Inline:
706 return 1;
707 }
708 llvm_unreachable("Unknown jump table encoding!");
709 }
710
711 /// createJumpTableIndex - Create a new jump table entry in the jump table info.
712 ///
createJumpTableIndex(const std::vector<MachineBasicBlock * > & DestBBs)713 unsigned MachineJumpTableInfo::createJumpTableIndex(
714 const std::vector<MachineBasicBlock*> &DestBBs) {
715 assert(!DestBBs.empty() && "Cannot create an empty jump table!");
716 JumpTables.push_back(MachineJumpTableEntry(DestBBs));
717 return JumpTables.size()-1;
718 }
719
720 /// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
721 /// the jump tables to branch to New instead.
ReplaceMBBInJumpTables(MachineBasicBlock * Old,MachineBasicBlock * New)722 bool MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
723 MachineBasicBlock *New) {
724 assert(Old != New && "Not making a change?");
725 bool MadeChange = false;
726 for (size_t i = 0, e = JumpTables.size(); i != e; ++i)
727 ReplaceMBBInJumpTable(i, Old, New);
728 return MadeChange;
729 }
730
731 /// ReplaceMBBInJumpTable - If Old is a target of the jump tables, update
732 /// the jump table to branch to New instead.
ReplaceMBBInJumpTable(unsigned Idx,MachineBasicBlock * Old,MachineBasicBlock * New)733 bool MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx,
734 MachineBasicBlock *Old,
735 MachineBasicBlock *New) {
736 assert(Old != New && "Not making a change?");
737 bool MadeChange = false;
738 MachineJumpTableEntry &JTE = JumpTables[Idx];
739 for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
740 if (JTE.MBBs[j] == Old) {
741 JTE.MBBs[j] = New;
742 MadeChange = true;
743 }
744 return MadeChange;
745 }
746
print(raw_ostream & OS) const747 void MachineJumpTableInfo::print(raw_ostream &OS) const {
748 if (JumpTables.empty()) return;
749
750 OS << "Jump Tables:\n";
751
752 for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
753 OS << " jt#" << i << ": ";
754 for (unsigned j = 0, f = JumpTables[i].MBBs.size(); j != f; ++j)
755 OS << " BB#" << JumpTables[i].MBBs[j]->getNumber();
756 }
757
758 OS << '\n';
759 }
760
761 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump() const762 void MachineJumpTableInfo::dump() const { print(dbgs()); }
763 #endif
764
765
766 //===----------------------------------------------------------------------===//
767 // MachineConstantPool implementation
768 //===----------------------------------------------------------------------===//
769
anchor()770 void MachineConstantPoolValue::anchor() { }
771
getType() const772 Type *MachineConstantPoolEntry::getType() const {
773 if (isMachineConstantPoolEntry())
774 return Val.MachineCPVal->getType();
775 return Val.ConstVal->getType();
776 }
777
778
getRelocationInfo() const779 unsigned MachineConstantPoolEntry::getRelocationInfo() const {
780 if (isMachineConstantPoolEntry())
781 return Val.MachineCPVal->getRelocationInfo();
782 return Val.ConstVal->getRelocationInfo();
783 }
784
~MachineConstantPool()785 MachineConstantPool::~MachineConstantPool() {
786 for (unsigned i = 0, e = Constants.size(); i != e; ++i)
787 if (Constants[i].isMachineConstantPoolEntry())
788 delete Constants[i].Val.MachineCPVal;
789 for (DenseSet<MachineConstantPoolValue*>::iterator I =
790 MachineCPVsSharingEntries.begin(), E = MachineCPVsSharingEntries.end();
791 I != E; ++I)
792 delete *I;
793 }
794
795 /// CanShareConstantPoolEntry - Test whether the given two constants
796 /// can be allocated the same constant pool entry.
CanShareConstantPoolEntry(const Constant * A,const Constant * B,const DataLayout * TD)797 static bool CanShareConstantPoolEntry(const Constant *A, const Constant *B,
798 const DataLayout *TD) {
799 // Handle the trivial case quickly.
800 if (A == B) return true;
801
802 // If they have the same type but weren't the same constant, quickly
803 // reject them.
804 if (A->getType() == B->getType()) return false;
805
806 // We can't handle structs or arrays.
807 if (isa<StructType>(A->getType()) || isa<ArrayType>(A->getType()) ||
808 isa<StructType>(B->getType()) || isa<ArrayType>(B->getType()))
809 return false;
810
811 // For now, only support constants with the same size.
812 uint64_t StoreSize = TD->getTypeStoreSize(A->getType());
813 if (StoreSize != TD->getTypeStoreSize(B->getType()) ||
814 StoreSize > 128)
815 return false;
816
817 Type *IntTy = IntegerType::get(A->getContext(), StoreSize*8);
818
819 // Try constant folding a bitcast of both instructions to an integer. If we
820 // get two identical ConstantInt's, then we are good to share them. We use
821 // the constant folding APIs to do this so that we get the benefit of
822 // DataLayout.
823 if (isa<PointerType>(A->getType()))
824 A = ConstantFoldInstOperands(Instruction::PtrToInt, IntTy,
825 const_cast<Constant*>(A), TD);
826 else if (A->getType() != IntTy)
827 A = ConstantFoldInstOperands(Instruction::BitCast, IntTy,
828 const_cast<Constant*>(A), TD);
829 if (isa<PointerType>(B->getType()))
830 B = ConstantFoldInstOperands(Instruction::PtrToInt, IntTy,
831 const_cast<Constant*>(B), TD);
832 else if (B->getType() != IntTy)
833 B = ConstantFoldInstOperands(Instruction::BitCast, IntTy,
834 const_cast<Constant*>(B), TD);
835
836 return A == B;
837 }
838
839 /// getConstantPoolIndex - Create a new entry in the constant pool or return
840 /// an existing one. User must specify the log2 of the minimum required
841 /// alignment for the object.
842 ///
getConstantPoolIndex(const Constant * C,unsigned Alignment)843 unsigned MachineConstantPool::getConstantPoolIndex(const Constant *C,
844 unsigned Alignment) {
845 assert(Alignment && "Alignment must be specified!");
846 if (Alignment > PoolAlignment) PoolAlignment = Alignment;
847
848 // Check to see if we already have this constant.
849 //
850 // FIXME, this could be made much more efficient for large constant pools.
851 for (unsigned i = 0, e = Constants.size(); i != e; ++i)
852 if (!Constants[i].isMachineConstantPoolEntry() &&
853 CanShareConstantPoolEntry(Constants[i].Val.ConstVal, C, TD)) {
854 if ((unsigned)Constants[i].getAlignment() < Alignment)
855 Constants[i].Alignment = Alignment;
856 return i;
857 }
858
859 Constants.push_back(MachineConstantPoolEntry(C, Alignment));
860 return Constants.size()-1;
861 }
862
getConstantPoolIndex(MachineConstantPoolValue * V,unsigned Alignment)863 unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
864 unsigned Alignment) {
865 assert(Alignment && "Alignment must be specified!");
866 if (Alignment > PoolAlignment) PoolAlignment = Alignment;
867
868 // Check to see if we already have this constant.
869 //
870 // FIXME, this could be made much more efficient for large constant pools.
871 int Idx = V->getExistingMachineCPValue(this, Alignment);
872 if (Idx != -1) {
873 MachineCPVsSharingEntries.insert(V);
874 return (unsigned)Idx;
875 }
876
877 Constants.push_back(MachineConstantPoolEntry(V, Alignment));
878 return Constants.size()-1;
879 }
880
print(raw_ostream & OS) const881 void MachineConstantPool::print(raw_ostream &OS) const {
882 if (Constants.empty()) return;
883
884 OS << "Constant Pool:\n";
885 for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
886 OS << " cp#" << i << ": ";
887 if (Constants[i].isMachineConstantPoolEntry())
888 Constants[i].Val.MachineCPVal->print(OS);
889 else
890 OS << *(const Value*)Constants[i].Val.ConstVal;
891 OS << ", align=" << Constants[i].getAlignment();
892 OS << "\n";
893 }
894 }
895
896 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump() const897 void MachineConstantPool::dump() const { print(dbgs()); }
898 #endif
899