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/DerivedTypes.h"
17 #include "llvm/Function.h"
18 #include "llvm/Instructions.h"
19 #include "llvm/Config/config.h"
20 #include "llvm/CodeGen/MachineConstantPool.h"
21 #include "llvm/CodeGen/MachineFunction.h"
22 #include "llvm/CodeGen/MachineFunctionPass.h"
23 #include "llvm/CodeGen/MachineFrameInfo.h"
24 #include "llvm/CodeGen/MachineInstr.h"
25 #include "llvm/CodeGen/MachineJumpTableInfo.h"
26 #include "llvm/CodeGen/MachineModuleInfo.h"
27 #include "llvm/CodeGen/MachineRegisterInfo.h"
28 #include "llvm/CodeGen/Passes.h"
29 #include "llvm/MC/MCAsmInfo.h"
30 #include "llvm/MC/MCContext.h"
31 #include "llvm/Analysis/DebugInfo.h"
32 #include "llvm/Support/Debug.h"
33 #include "llvm/Target/TargetData.h"
34 #include "llvm/Target/TargetLowering.h"
35 #include "llvm/Target/TargetMachine.h"
36 #include "llvm/Target/TargetFrameInfo.h"
37 #include "llvm/ADT/SmallString.h"
38 #include "llvm/ADT/STLExtras.h"
39 #include "llvm/Support/GraphWriter.h"
40 #include "llvm/Support/raw_ostream.h"
41 using namespace llvm;
42 
43 //===----------------------------------------------------------------------===//
44 // MachineFunction implementation
45 //===----------------------------------------------------------------------===//
46 
47 // Out of line virtual method.
48 MachineFunctionInfo::~MachineFunctionInfo() {}
49 
50 void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
51   MBB->getParent()->DeleteMachineBasicBlock(MBB);
52 }
53 
54 MachineFunction::MachineFunction(const Function *F, const TargetMachine &TM,
55                                  unsigned FunctionNum, MachineModuleInfo &mmi)
56   : Fn(F), Target(TM), Ctx(mmi.getContext()), MMI(mmi) {
57   if (TM.getRegisterInfo())
58     RegInfo = new (Allocator) MachineRegisterInfo(*TM.getRegisterInfo());
59   else
60     RegInfo = 0;
61   MFInfo = 0;
62   FrameInfo = new (Allocator) MachineFrameInfo(*TM.getFrameInfo());
63   if (Fn->hasFnAttr(Attribute::StackAlignment))
64     FrameInfo->setMaxAlignment(Attribute::getStackAlignmentFromAttrs(
65         Fn->getAttributes().getFnAttributes()));
66   ConstantPool = new (Allocator) MachineConstantPool(TM.getTargetData());
67   Alignment = TM.getTargetLowering()->getFunctionAlignment(F);
68   FunctionNumber = FunctionNum;
69   JumpTableInfo = 0;
70 }
71 
72 MachineFunction::~MachineFunction() {
73   BasicBlocks.clear();
74   InstructionRecycler.clear(Allocator);
75   BasicBlockRecycler.clear(Allocator);
76   if (RegInfo) {
77     RegInfo->~MachineRegisterInfo();
78     Allocator.Deallocate(RegInfo);
79   }
80   if (MFInfo) {
81     MFInfo->~MachineFunctionInfo();
82     Allocator.Deallocate(MFInfo);
83   }
84   FrameInfo->~MachineFrameInfo();         Allocator.Deallocate(FrameInfo);
85   ConstantPool->~MachineConstantPool();   Allocator.Deallocate(ConstantPool);
86 
87   if (JumpTableInfo) {
88     JumpTableInfo->~MachineJumpTableInfo();
89     Allocator.Deallocate(JumpTableInfo);
90   }
91 }
92 
93 /// getOrCreateJumpTableInfo - Get the JumpTableInfo for this function, if it
94 /// does already exist, allocate one.
95 MachineJumpTableInfo *MachineFunction::
96 getOrCreateJumpTableInfo(unsigned EntryKind) {
97   if (JumpTableInfo) return JumpTableInfo;
98 
99   JumpTableInfo = new (Allocator)
100     MachineJumpTableInfo((MachineJumpTableInfo::JTEntryKind)EntryKind);
101   return JumpTableInfo;
102 }
103 
104 /// RenumberBlocks - This discards all of the MachineBasicBlock numbers and
105 /// recomputes them.  This guarantees that the MBB numbers are sequential,
106 /// dense, and match the ordering of the blocks within the function.  If a
107 /// specific MachineBasicBlock is specified, only that block and those after
108 /// it are renumbered.
109 void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
110   if (empty()) { MBBNumbering.clear(); return; }
111   MachineFunction::iterator MBBI, E = end();
112   if (MBB == 0)
113     MBBI = begin();
114   else
115     MBBI = MBB;
116 
117   // Figure out the block number this should have.
118   unsigned BlockNo = 0;
119   if (MBBI != begin())
120     BlockNo = prior(MBBI)->getNumber()+1;
121 
122   for (; MBBI != E; ++MBBI, ++BlockNo) {
123     if (MBBI->getNumber() != (int)BlockNo) {
124       // Remove use of the old number.
125       if (MBBI->getNumber() != -1) {
126         assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
127                "MBB number mismatch!");
128         MBBNumbering[MBBI->getNumber()] = 0;
129       }
130 
131       // If BlockNo is already taken, set that block's number to -1.
132       if (MBBNumbering[BlockNo])
133         MBBNumbering[BlockNo]->setNumber(-1);
134 
135       MBBNumbering[BlockNo] = MBBI;
136       MBBI->setNumber(BlockNo);
137     }
138   }
139 
140   // Okay, all the blocks are renumbered.  If we have compactified the block
141   // numbering, shrink MBBNumbering now.
142   assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
143   MBBNumbering.resize(BlockNo);
144 }
145 
146 /// CreateMachineInstr - Allocate a new MachineInstr. Use this instead
147 /// of `new MachineInstr'.
148 ///
149 MachineInstr *
150 MachineFunction::CreateMachineInstr(const TargetInstrDesc &TID,
151                                     DebugLoc DL, bool NoImp) {
152   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
153     MachineInstr(TID, DL, NoImp);
154 }
155 
156 /// CloneMachineInstr - Create a new MachineInstr which is a copy of the
157 /// 'Orig' instruction, identical in all ways except the instruction
158 /// has no parent, prev, or next.
159 ///
160 MachineInstr *
161 MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
162   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
163              MachineInstr(*this, *Orig);
164 }
165 
166 /// DeleteMachineInstr - Delete the given MachineInstr.
167 ///
168 void
169 MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
170   MI->~MachineInstr();
171   InstructionRecycler.Deallocate(Allocator, MI);
172 }
173 
174 /// CreateMachineBasicBlock - Allocate a new MachineBasicBlock. Use this
175 /// instead of `new MachineBasicBlock'.
176 ///
177 MachineBasicBlock *
178 MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
179   return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
180              MachineBasicBlock(*this, bb);
181 }
182 
183 /// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
184 ///
185 void
186 MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
187   assert(MBB->getParent() == this && "MBB parent mismatch!");
188   MBB->~MachineBasicBlock();
189   BasicBlockRecycler.Deallocate(Allocator, MBB);
190 }
191 
192 MachineMemOperand *
193 MachineFunction::getMachineMemOperand(MachinePointerInfo PtrInfo, unsigned f,
194                                       uint64_t s, unsigned base_alignment,
195                                       const MDNode *TBAAInfo) {
196   return new (Allocator) MachineMemOperand(PtrInfo, f, s, base_alignment,
197                                            TBAAInfo);
198 }
199 
200 MachineMemOperand *
201 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
202                                       int64_t Offset, uint64_t Size) {
203   return new (Allocator)
204              MachineMemOperand(MachinePointerInfo(MMO->getValue(),
205                                                   MMO->getOffset()+Offset),
206                                MMO->getFlags(), Size,
207                                MMO->getBaseAlignment(), 0);
208 }
209 
210 MachineInstr::mmo_iterator
211 MachineFunction::allocateMemRefsArray(unsigned long Num) {
212   return Allocator.Allocate<MachineMemOperand *>(Num);
213 }
214 
215 std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
216 MachineFunction::extractLoadMemRefs(MachineInstr::mmo_iterator Begin,
217                                     MachineInstr::mmo_iterator End) {
218   // Count the number of load mem refs.
219   unsigned Num = 0;
220   for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
221     if ((*I)->isLoad())
222       ++Num;
223 
224   // Allocate a new array and populate it with the load information.
225   MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
226   unsigned Index = 0;
227   for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
228     if ((*I)->isLoad()) {
229       if (!(*I)->isStore())
230         // Reuse the MMO.
231         Result[Index] = *I;
232       else {
233         // Clone the MMO and unset the store flag.
234         MachineMemOperand *JustLoad =
235           getMachineMemOperand((*I)->getPointerInfo(),
236                                (*I)->getFlags() & ~MachineMemOperand::MOStore,
237                                (*I)->getSize(), (*I)->getBaseAlignment(),
238                                (*I)->getTBAAInfo());
239         Result[Index] = JustLoad;
240       }
241       ++Index;
242     }
243   }
244   return std::make_pair(Result, Result + Num);
245 }
246 
247 std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
248 MachineFunction::extractStoreMemRefs(MachineInstr::mmo_iterator Begin,
249                                      MachineInstr::mmo_iterator End) {
250   // Count the number of load mem refs.
251   unsigned Num = 0;
252   for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
253     if ((*I)->isStore())
254       ++Num;
255 
256   // Allocate a new array and populate it with the store information.
257   MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
258   unsigned Index = 0;
259   for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
260     if ((*I)->isStore()) {
261       if (!(*I)->isLoad())
262         // Reuse the MMO.
263         Result[Index] = *I;
264       else {
265         // Clone the MMO and unset the load flag.
266         MachineMemOperand *JustStore =
267           getMachineMemOperand((*I)->getPointerInfo(),
268                                (*I)->getFlags() & ~MachineMemOperand::MOLoad,
269                                (*I)->getSize(), (*I)->getBaseAlignment(),
270                                (*I)->getTBAAInfo());
271         Result[Index] = JustStore;
272       }
273       ++Index;
274     }
275   }
276   return std::make_pair(Result, Result + Num);
277 }
278 
279 void MachineFunction::dump() const {
280   print(dbgs());
281 }
282 
283 void MachineFunction::print(raw_ostream &OS, SlotIndexes *Indexes) const {
284   OS << "# Machine code for function " << Fn->getName() << ":\n";
285 
286   // Print Frame Information
287   FrameInfo->print(*this, OS);
288 
289   // Print JumpTable Information
290   if (JumpTableInfo)
291     JumpTableInfo->print(OS);
292 
293   // Print Constant Pool
294   ConstantPool->print(OS);
295 
296   const TargetRegisterInfo *TRI = getTarget().getRegisterInfo();
297 
298   if (RegInfo && !RegInfo->livein_empty()) {
299     OS << "Function Live Ins: ";
300     for (MachineRegisterInfo::livein_iterator
301          I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
302       if (TRI)
303         OS << "%" << TRI->getName(I->first);
304       else
305         OS << " %physreg" << I->first;
306 
307       if (I->second)
308         OS << " in reg%" << I->second;
309 
310       if (llvm::next(I) != E)
311         OS << ", ";
312     }
313     OS << '\n';
314   }
315   if (RegInfo && !RegInfo->liveout_empty()) {
316     OS << "Function Live Outs: ";
317     for (MachineRegisterInfo::liveout_iterator
318          I = RegInfo->liveout_begin(), E = RegInfo->liveout_end(); I != E; ++I){
319       if (TRI)
320         OS << '%' << TRI->getName(*I);
321       else
322         OS << "%physreg" << *I;
323 
324       if (llvm::next(I) != E)
325         OS << " ";
326     }
327     OS << '\n';
328   }
329 
330   for (const_iterator BB = begin(), E = end(); BB != E; ++BB) {
331     OS << '\n';
332     BB->print(OS, Indexes);
333   }
334 
335   OS << "\n# End machine code for function " << Fn->getName() << ".\n\n";
336 }
337 
338 namespace llvm {
339   template<>
340   struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
341 
342   DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {}
343 
344     static std::string getGraphName(const MachineFunction *F) {
345       return "CFG for '" + F->getFunction()->getNameStr() + "' function";
346     }
347 
348     std::string getNodeLabel(const MachineBasicBlock *Node,
349                              const MachineFunction *Graph) {
350       std::string OutStr;
351       {
352         raw_string_ostream OSS(OutStr);
353 
354         if (isSimple()) {
355           OSS << "BB#" << Node->getNumber();
356           if (const BasicBlock *BB = Node->getBasicBlock())
357             OSS << ": " << BB->getName();
358         } else
359           Node->print(OSS);
360       }
361 
362       if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
363 
364       // Process string output to make it nicer...
365       for (unsigned i = 0; i != OutStr.length(); ++i)
366         if (OutStr[i] == '\n') {                            // Left justify
367           OutStr[i] = '\\';
368           OutStr.insert(OutStr.begin()+i+1, 'l');
369         }
370       return OutStr;
371     }
372   };
373 }
374 
375 void MachineFunction::viewCFG() const
376 {
377 #ifndef NDEBUG
378   ViewGraph(this, "mf" + getFunction()->getNameStr());
379 #else
380   errs() << "MachineFunction::viewCFG is only available in debug builds on "
381          << "systems with Graphviz or gv!\n";
382 #endif // NDEBUG
383 }
384 
385 void MachineFunction::viewCFGOnly() const
386 {
387 #ifndef NDEBUG
388   ViewGraph(this, "mf" + getFunction()->getNameStr(), true);
389 #else
390   errs() << "MachineFunction::viewCFGOnly is only available in debug builds on "
391          << "systems with Graphviz or gv!\n";
392 #endif // NDEBUG
393 }
394 
395 /// addLiveIn - Add the specified physical register as a live-in value and
396 /// create a corresponding virtual register for it.
397 unsigned MachineFunction::addLiveIn(unsigned PReg,
398                                     const TargetRegisterClass *RC) {
399   MachineRegisterInfo &MRI = getRegInfo();
400   unsigned VReg = MRI.getLiveInVirtReg(PReg);
401   if (VReg) {
402     assert(MRI.getRegClass(VReg) == RC && "Register class mismatch!");
403     return VReg;
404   }
405   VReg = MRI.createVirtualRegister(RC);
406   MRI.addLiveIn(PReg, VReg);
407   return VReg;
408 }
409 
410 /// getJTISymbol - Return the MCSymbol for the specified non-empty jump table.
411 /// If isLinkerPrivate is specified, an 'l' label is returned, otherwise a
412 /// normal 'L' label is returned.
413 MCSymbol *MachineFunction::getJTISymbol(unsigned JTI, MCContext &Ctx,
414                                         bool isLinkerPrivate) const {
415   assert(JumpTableInfo && "No jump tables");
416 
417   assert(JTI < JumpTableInfo->getJumpTables().size() && "Invalid JTI!");
418   const MCAsmInfo &MAI = *getTarget().getMCAsmInfo();
419 
420   const char *Prefix = isLinkerPrivate ? MAI.getLinkerPrivateGlobalPrefix() :
421                                          MAI.getPrivateGlobalPrefix();
422   SmallString<60> Name;
423   raw_svector_ostream(Name)
424     << Prefix << "JTI" << getFunctionNumber() << '_' << JTI;
425   return Ctx.GetOrCreateSymbol(Name.str());
426 }
427 
428 
429 //===----------------------------------------------------------------------===//
430 //  MachineFrameInfo implementation
431 //===----------------------------------------------------------------------===//
432 
433 /// CreateFixedObject - Create a new object at a fixed location on the stack.
434 /// All fixed objects should be created before other objects are created for
435 /// efficiency. By default, fixed objects are immutable. This returns an
436 /// index with a negative value.
437 ///
438 int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
439                                         bool Immutable) {
440   assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
441   // The alignment of the frame index can be determined from its offset from
442   // the incoming frame position.  If the frame object is at offset 32 and
443   // the stack is guaranteed to be 16-byte aligned, then we know that the
444   // object is 16-byte aligned.
445   unsigned StackAlign = TFI.getStackAlignment();
446   unsigned Align = MinAlign(SPOffset, StackAlign);
447   Objects.insert(Objects.begin(), StackObject(Size, Align, SPOffset, Immutable,
448                                               /*isSS*/false, false));
449   return -++NumFixedObjects;
450 }
451 
452 
453 BitVector
454 MachineFrameInfo::getPristineRegs(const MachineBasicBlock *MBB) const {
455   assert(MBB && "MBB must be valid");
456   const MachineFunction *MF = MBB->getParent();
457   assert(MF && "MBB must be part of a MachineFunction");
458   const TargetMachine &TM = MF->getTarget();
459   const TargetRegisterInfo *TRI = TM.getRegisterInfo();
460   BitVector BV(TRI->getNumRegs());
461 
462   // Before CSI is calculated, no registers are considered pristine. They can be
463   // freely used and PEI will make sure they are saved.
464   if (!isCalleeSavedInfoValid())
465     return BV;
466 
467   for (const unsigned *CSR = TRI->getCalleeSavedRegs(MF); CSR && *CSR; ++CSR)
468     BV.set(*CSR);
469 
470   // The entry MBB always has all CSRs pristine.
471   if (MBB == &MF->front())
472     return BV;
473 
474   // On other MBBs the saved CSRs are not pristine.
475   const std::vector<CalleeSavedInfo> &CSI = getCalleeSavedInfo();
476   for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(),
477          E = CSI.end(); I != E; ++I)
478     BV.reset(I->getReg());
479 
480   return BV;
481 }
482 
483 
484 void MachineFrameInfo::print(const MachineFunction &MF, raw_ostream &OS) const{
485   if (Objects.empty()) return;
486 
487   const TargetFrameInfo *FI = MF.getTarget().getFrameInfo();
488   int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
489 
490   OS << "Frame Objects:\n";
491 
492   for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
493     const StackObject &SO = Objects[i];
494     OS << "  fi#" << (int)(i-NumFixedObjects) << ": ";
495     if (SO.Size == ~0ULL) {
496       OS << "dead\n";
497       continue;
498     }
499     if (SO.Size == 0)
500       OS << "variable sized";
501     else
502       OS << "size=" << SO.Size;
503     OS << ", align=" << SO.Alignment;
504 
505     if (i < NumFixedObjects)
506       OS << ", fixed";
507     if (i < NumFixedObjects || SO.SPOffset != -1) {
508       int64_t Off = SO.SPOffset - ValOffset;
509       OS << ", at location [SP";
510       if (Off > 0)
511         OS << "+" << Off;
512       else if (Off < 0)
513         OS << Off;
514       OS << "]";
515     }
516     OS << "\n";
517   }
518 }
519 
520 void MachineFrameInfo::dump(const MachineFunction &MF) const {
521   print(MF, dbgs());
522 }
523 
524 //===----------------------------------------------------------------------===//
525 //  MachineJumpTableInfo implementation
526 //===----------------------------------------------------------------------===//
527 
528 /// getEntrySize - Return the size of each entry in the jump table.
529 unsigned MachineJumpTableInfo::getEntrySize(const TargetData &TD) const {
530   // The size of a jump table entry is 4 bytes unless the entry is just the
531   // address of a block, in which case it is the pointer size.
532   switch (getEntryKind()) {
533   case MachineJumpTableInfo::EK_BlockAddress:
534     return TD.getPointerSize();
535   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
536   case MachineJumpTableInfo::EK_LabelDifference32:
537   case MachineJumpTableInfo::EK_Custom32:
538     return 4;
539   case MachineJumpTableInfo::EK_Inline:
540     return 0;
541   }
542   assert(0 && "Unknown jump table encoding!");
543   return ~0;
544 }
545 
546 /// getEntryAlignment - Return the alignment of each entry in the jump table.
547 unsigned MachineJumpTableInfo::getEntryAlignment(const TargetData &TD) const {
548   // The alignment of a jump table entry is the alignment of int32 unless the
549   // entry is just the address of a block, in which case it is the pointer
550   // alignment.
551   switch (getEntryKind()) {
552   case MachineJumpTableInfo::EK_BlockAddress:
553     return TD.getPointerABIAlignment();
554   case MachineJumpTableInfo::EK_GPRel32BlockAddress:
555   case MachineJumpTableInfo::EK_LabelDifference32:
556   case MachineJumpTableInfo::EK_Custom32:
557     return TD.getABIIntegerTypeAlignment(32);
558   case MachineJumpTableInfo::EK_Inline:
559     return 1;
560   }
561   assert(0 && "Unknown jump table encoding!");
562   return ~0;
563 }
564 
565 /// createJumpTableIndex - Create a new jump table entry in the jump table info.
566 ///
567 unsigned MachineJumpTableInfo::createJumpTableIndex(
568                                const std::vector<MachineBasicBlock*> &DestBBs) {
569   assert(!DestBBs.empty() && "Cannot create an empty jump table!");
570   JumpTables.push_back(MachineJumpTableEntry(DestBBs));
571   return JumpTables.size()-1;
572 }
573 
574 /// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
575 /// the jump tables to branch to New instead.
576 bool MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
577                                                   MachineBasicBlock *New) {
578   assert(Old != New && "Not making a change?");
579   bool MadeChange = false;
580   for (size_t i = 0, e = JumpTables.size(); i != e; ++i)
581     ReplaceMBBInJumpTable(i, Old, New);
582   return MadeChange;
583 }
584 
585 /// ReplaceMBBInJumpTable - If Old is a target of the jump tables, update
586 /// the jump table to branch to New instead.
587 bool MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx,
588                                                  MachineBasicBlock *Old,
589                                                  MachineBasicBlock *New) {
590   assert(Old != New && "Not making a change?");
591   bool MadeChange = false;
592   MachineJumpTableEntry &JTE = JumpTables[Idx];
593   for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
594     if (JTE.MBBs[j] == Old) {
595       JTE.MBBs[j] = New;
596       MadeChange = true;
597     }
598   return MadeChange;
599 }
600 
601 void MachineJumpTableInfo::print(raw_ostream &OS) const {
602   if (JumpTables.empty()) return;
603 
604   OS << "Jump Tables:\n";
605 
606   for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
607     OS << "  jt#" << i << ": ";
608     for (unsigned j = 0, f = JumpTables[i].MBBs.size(); j != f; ++j)
609       OS << " BB#" << JumpTables[i].MBBs[j]->getNumber();
610   }
611 
612   OS << '\n';
613 }
614 
615 void MachineJumpTableInfo::dump() const { print(dbgs()); }
616 
617 
618 //===----------------------------------------------------------------------===//
619 //  MachineConstantPool implementation
620 //===----------------------------------------------------------------------===//
621 
622 const Type *MachineConstantPoolEntry::getType() const {
623   if (isMachineConstantPoolEntry())
624     return Val.MachineCPVal->getType();
625   return Val.ConstVal->getType();
626 }
627 
628 
629 unsigned MachineConstantPoolEntry::getRelocationInfo() const {
630   if (isMachineConstantPoolEntry())
631     return Val.MachineCPVal->getRelocationInfo();
632   return Val.ConstVal->getRelocationInfo();
633 }
634 
635 MachineConstantPool::~MachineConstantPool() {
636   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
637     if (Constants[i].isMachineConstantPoolEntry())
638       delete Constants[i].Val.MachineCPVal;
639 }
640 
641 /// CanShareConstantPoolEntry - Test whether the given two constants
642 /// can be allocated the same constant pool entry.
643 static bool CanShareConstantPoolEntry(const Constant *A, const Constant *B,
644                                       const TargetData *TD) {
645   // Handle the trivial case quickly.
646   if (A == B) return true;
647 
648   // If they have the same type but weren't the same constant, quickly
649   // reject them.
650   if (A->getType() == B->getType()) return false;
651 
652   // For now, only support constants with the same size.
653   if (TD->getTypeStoreSize(A->getType()) != TD->getTypeStoreSize(B->getType()))
654     return false;
655 
656   // If a floating-point value and an integer value have the same encoding,
657   // they can share a constant-pool entry.
658   if (const ConstantFP *AFP = dyn_cast<ConstantFP>(A))
659     if (const ConstantInt *BI = dyn_cast<ConstantInt>(B))
660       return AFP->getValueAPF().bitcastToAPInt() == BI->getValue();
661   if (const ConstantFP *BFP = dyn_cast<ConstantFP>(B))
662     if (const ConstantInt *AI = dyn_cast<ConstantInt>(A))
663       return BFP->getValueAPF().bitcastToAPInt() == AI->getValue();
664 
665   // Two vectors can share an entry if each pair of corresponding
666   // elements could.
667   if (const ConstantVector *AV = dyn_cast<ConstantVector>(A))
668     if (const ConstantVector *BV = dyn_cast<ConstantVector>(B)) {
669       if (AV->getType()->getNumElements() != BV->getType()->getNumElements())
670         return false;
671       for (unsigned i = 0, e = AV->getType()->getNumElements(); i != e; ++i)
672         if (!CanShareConstantPoolEntry(AV->getOperand(i),
673                                        BV->getOperand(i), TD))
674           return false;
675       return true;
676     }
677 
678   // TODO: Handle other cases.
679 
680   return false;
681 }
682 
683 /// getConstantPoolIndex - Create a new entry in the constant pool or return
684 /// an existing one.  User must specify the log2 of the minimum required
685 /// alignment for the object.
686 ///
687 unsigned MachineConstantPool::getConstantPoolIndex(const Constant *C,
688                                                    unsigned Alignment) {
689   assert(Alignment && "Alignment must be specified!");
690   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
691 
692   // Check to see if we already have this constant.
693   //
694   // FIXME, this could be made much more efficient for large constant pools.
695   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
696     if (!Constants[i].isMachineConstantPoolEntry() &&
697         CanShareConstantPoolEntry(Constants[i].Val.ConstVal, C, TD)) {
698       if ((unsigned)Constants[i].getAlignment() < Alignment)
699         Constants[i].Alignment = Alignment;
700       return i;
701     }
702 
703   Constants.push_back(MachineConstantPoolEntry(C, Alignment));
704   return Constants.size()-1;
705 }
706 
707 unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
708                                                    unsigned Alignment) {
709   assert(Alignment && "Alignment must be specified!");
710   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
711 
712   // Check to see if we already have this constant.
713   //
714   // FIXME, this could be made much more efficient for large constant pools.
715   int Idx = V->getExistingMachineCPValue(this, Alignment);
716   if (Idx != -1)
717     return (unsigned)Idx;
718 
719   Constants.push_back(MachineConstantPoolEntry(V, Alignment));
720   return Constants.size()-1;
721 }
722 
723 void MachineConstantPool::print(raw_ostream &OS) const {
724   if (Constants.empty()) return;
725 
726   OS << "Constant Pool:\n";
727   for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
728     OS << "  cp#" << i << ": ";
729     if (Constants[i].isMachineConstantPoolEntry())
730       Constants[i].Val.MachineCPVal->print(OS);
731     else
732       OS << *(Value*)Constants[i].Val.ConstVal;
733     OS << ", align=" << Constants[i].getAlignment();
734     OS << "\n";
735   }
736 }
737 
738 void MachineConstantPool::dump() const { print(dbgs()); }
739