xref: /llvm-project/llvm/lib/CodeGen/MachineFunction.cpp (revision 693e36a3e8f86a2095806744ad5f8963fbf74271) 
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/ADT/STLExtras.h"
20 #include "llvm/Config/config.h"
21 #include "llvm/CodeGen/MachineConstantPool.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/MachineRegisterInfo.h"
27 #include "llvm/CodeGen/Passes.h"
28 #include "llvm/Target/TargetData.h"
29 #include "llvm/Target/TargetLowering.h"
30 #include "llvm/Target/TargetMachine.h"
31 #include "llvm/Target/TargetFrameInfo.h"
32 #include "llvm/Support/Compiler.h"
33 #include "llvm/Support/GraphWriter.h"
34 #include "llvm/Support/raw_ostream.h"
35 #include <fstream>
36 #include <sstream>
37 using namespace llvm;
38 
39 namespace {
40   struct VISIBILITY_HIDDEN Printer : public MachineFunctionPass {
41     static char ID;
42 
43     std::ostream *OS;
44     const std::string Banner;
45 
46     Printer (std::ostream *os, const std::string &banner)
47       : MachineFunctionPass(&ID), OS(os), Banner(banner) {}
48 
49     const char *getPassName() const { return "MachineFunction Printer"; }
50 
51     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
52       AU.setPreservesAll();
53       MachineFunctionPass::getAnalysisUsage(AU);
54     }
55 
56     bool runOnMachineFunction(MachineFunction &MF) {
57       (*OS) << Banner;
58       MF.print (*OS);
59       return false;
60     }
61   };
62   char Printer::ID = 0;
63 }
64 
65 /// Returns a newly-created MachineFunction Printer pass. The default banner is
66 /// empty.
67 ///
68 FunctionPass *llvm::createMachineFunctionPrinterPass(std::ostream *OS,
69                                                      const std::string &Banner){
70   return new Printer(OS, Banner);
71 }
72 
73 //===---------------------------------------------------------------------===//
74 // MachineFunction implementation
75 //===---------------------------------------------------------------------===//
76 
77 void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) {
78   MBB->getParent()->DeleteMachineBasicBlock(MBB);
79 }
80 
81 MachineFunction::MachineFunction(Function *F,
82                                  const TargetMachine &TM)
83   : Fn(F), Target(TM) {
84   if (TM.getRegisterInfo())
85     RegInfo = new (Allocator.Allocate<MachineRegisterInfo>())
86                   MachineRegisterInfo(*TM.getRegisterInfo());
87   else
88     RegInfo = 0;
89   MFInfo = 0;
90   FrameInfo = new (Allocator.Allocate<MachineFrameInfo>())
91                   MachineFrameInfo(*TM.getFrameInfo());
92   ConstantPool = new (Allocator.Allocate<MachineConstantPool>())
93                      MachineConstantPool(TM.getTargetData());
94   Alignment = TM.getTargetLowering()->getFunctionAlignment(F);
95 
96   CallSiteIndex = 0;
97   MaxCallSiteIndex = 0;
98 
99   // Set up jump table.
100   const TargetData &TD = *TM.getTargetData();
101   bool IsPic = TM.getRelocationModel() == Reloc::PIC_;
102   unsigned EntrySize = IsPic ? 4 : TD.getPointerSize();
103   unsigned TyAlignment = IsPic ? TD.getABITypeAlignment(Type::Int32Ty)
104                                : TD.getPointerABIAlignment();
105   JumpTableInfo = new (Allocator.Allocate<MachineJumpTableInfo>())
106                       MachineJumpTableInfo(EntrySize, TyAlignment);
107 }
108 
109 MachineFunction::~MachineFunction() {
110   BasicBlocks.clear();
111   InstructionRecycler.clear(Allocator);
112   BasicBlockRecycler.clear(Allocator);
113   if (RegInfo) {
114     RegInfo->~MachineRegisterInfo();
115     Allocator.Deallocate(RegInfo);
116   }
117   if (MFInfo) {
118     MFInfo->~MachineFunctionInfo();
119     Allocator.Deallocate(MFInfo);
120   }
121   FrameInfo->~MachineFrameInfo();         Allocator.Deallocate(FrameInfo);
122   ConstantPool->~MachineConstantPool();   Allocator.Deallocate(ConstantPool);
123   JumpTableInfo->~MachineJumpTableInfo(); Allocator.Deallocate(JumpTableInfo);
124 }
125 
126 
127 /// RenumberBlocks - This discards all of the MachineBasicBlock numbers and
128 /// recomputes them.  This guarantees that the MBB numbers are sequential,
129 /// dense, and match the ordering of the blocks within the function.  If a
130 /// specific MachineBasicBlock is specified, only that block and those after
131 /// it are renumbered.
132 void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
133   if (empty()) { MBBNumbering.clear(); return; }
134   MachineFunction::iterator MBBI, E = end();
135   if (MBB == 0)
136     MBBI = begin();
137   else
138     MBBI = MBB;
139 
140   // Figure out the block number this should have.
141   unsigned BlockNo = 0;
142   if (MBBI != begin())
143     BlockNo = prior(MBBI)->getNumber()+1;
144 
145   for (; MBBI != E; ++MBBI, ++BlockNo) {
146     if (MBBI->getNumber() != (int)BlockNo) {
147       // Remove use of the old number.
148       if (MBBI->getNumber() != -1) {
149         assert(MBBNumbering[MBBI->getNumber()] == &*MBBI &&
150                "MBB number mismatch!");
151         MBBNumbering[MBBI->getNumber()] = 0;
152       }
153 
154       // If BlockNo is already taken, set that block's number to -1.
155       if (MBBNumbering[BlockNo])
156         MBBNumbering[BlockNo]->setNumber(-1);
157 
158       MBBNumbering[BlockNo] = MBBI;
159       MBBI->setNumber(BlockNo);
160     }
161   }
162 
163   // Okay, all the blocks are renumbered.  If we have compactified the block
164   // numbering, shrink MBBNumbering now.
165   assert(BlockNo <= MBBNumbering.size() && "Mismatch!");
166   MBBNumbering.resize(BlockNo);
167 }
168 
169 /// CreateMachineInstr - Allocate a new MachineInstr. Use this instead
170 /// of `new MachineInstr'.
171 ///
172 MachineInstr *
173 MachineFunction::CreateMachineInstr(const TargetInstrDesc &TID,
174                                     DebugLoc DL, bool NoImp) {
175   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
176     MachineInstr(TID, DL, NoImp);
177 }
178 
179 /// CloneMachineInstr - Create a new MachineInstr which is a copy of the
180 /// 'Orig' instruction, identical in all ways except the the instruction
181 /// has no parent, prev, or next.
182 ///
183 MachineInstr *
184 MachineFunction::CloneMachineInstr(const MachineInstr *Orig) {
185   return new (InstructionRecycler.Allocate<MachineInstr>(Allocator))
186              MachineInstr(*this, *Orig);
187 }
188 
189 /// DeleteMachineInstr - Delete the given MachineInstr.
190 ///
191 void
192 MachineFunction::DeleteMachineInstr(MachineInstr *MI) {
193   // Clear the instructions memoperands. This must be done manually because
194   // the instruction's parent pointer is now null, so it can't properly
195   // deallocate them on its own.
196   MI->clearMemOperands(*this);
197 
198   MI->~MachineInstr();
199   InstructionRecycler.Deallocate(Allocator, MI);
200 }
201 
202 /// CreateMachineBasicBlock - Allocate a new MachineBasicBlock. Use this
203 /// instead of `new MachineBasicBlock'.
204 ///
205 MachineBasicBlock *
206 MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) {
207   return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator))
208              MachineBasicBlock(*this, bb);
209 }
210 
211 /// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
212 ///
213 void
214 MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) {
215   assert(MBB->getParent() == this && "MBB parent mismatch!");
216   MBB->~MachineBasicBlock();
217   BasicBlockRecycler.Deallocate(Allocator, MBB);
218 }
219 
220 void MachineFunction::dump() const {
221   print(*cerr.stream());
222 }
223 
224 void MachineFunction::print(std::ostream &OS,
225                             const PrefixPrinter &prefix) const {
226   OS << "# Machine code for " << Fn->getNameStr () << "():\n";
227 
228   // Print Frame Information
229   FrameInfo->print(*this, OS);
230 
231   // Print JumpTable Information
232   JumpTableInfo->print(OS);
233 
234   // Print Constant Pool
235   {
236     raw_os_ostream OSS(OS);
237     ConstantPool->print(OSS);
238   }
239 
240   const TargetRegisterInfo *TRI = getTarget().getRegisterInfo();
241 
242   if (RegInfo && !RegInfo->livein_empty()) {
243     OS << "Live Ins:";
244     for (MachineRegisterInfo::livein_iterator
245          I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) {
246       if (TRI)
247         OS << " " << TRI->getName(I->first);
248       else
249         OS << " Reg #" << I->first;
250 
251       if (I->second)
252         OS << " in VR#" << I->second << " ";
253     }
254     OS << "\n";
255   }
256   if (RegInfo && !RegInfo->liveout_empty()) {
257     OS << "Live Outs:";
258     for (MachineRegisterInfo::liveout_iterator
259          I = RegInfo->liveout_begin(), E = RegInfo->liveout_end(); I != E; ++I)
260       if (TRI)
261         OS << " " << TRI->getName(*I);
262       else
263         OS << " Reg #" << *I;
264     OS << "\n";
265   }
266 
267   for (const_iterator BB = begin(); BB != end(); ++BB) {
268     prefix(OS, *BB);
269     BB->print(OS, prefix);
270   }
271 
272   OS << "\n# End machine code for " << Fn->getNameStr () << "().\n\n";
273 }
274 
275 namespace llvm {
276   template<>
277   struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits {
278     static std::string getGraphName(const MachineFunction *F) {
279       return "CFG for '" + F->getFunction()->getNameStr() + "' function";
280     }
281 
282     static std::string getNodeLabel(const MachineBasicBlock *Node,
283                                     const MachineFunction *Graph,
284                                     bool ShortNames) {
285       if (ShortNames && Node->getBasicBlock() &&
286           !Node->getBasicBlock()->getName().empty())
287         return Node->getBasicBlock()->getNameStr() + ":";
288 
289       std::ostringstream Out;
290       if (ShortNames) {
291         Out << Node->getNumber() << ':';
292         return Out.str();
293       }
294 
295       Node->print(Out);
296 
297       std::string OutStr = Out.str();
298       if (OutStr[0] == '\n') OutStr.erase(OutStr.begin());
299 
300       // Process string output to make it nicer...
301       for (unsigned i = 0; i != OutStr.length(); ++i)
302         if (OutStr[i] == '\n') {                            // Left justify
303           OutStr[i] = '\\';
304           OutStr.insert(OutStr.begin()+i+1, 'l');
305         }
306       return OutStr;
307     }
308   };
309 }
310 
311 void MachineFunction::viewCFG() const
312 {
313 #ifndef NDEBUG
314   ViewGraph(this, "mf" + getFunction()->getNameStr());
315 #else
316   cerr << "SelectionDAG::viewGraph is only available in debug builds on "
317        << "systems with Graphviz or gv!\n";
318 #endif // NDEBUG
319 }
320 
321 void MachineFunction::viewCFGOnly() const
322 {
323 #ifndef NDEBUG
324   ViewGraph(this, "mf" + getFunction()->getNameStr(), true);
325 #else
326   cerr << "SelectionDAG::viewGraph is only available in debug builds on "
327        << "systems with Graphviz or gv!\n";
328 #endif // NDEBUG
329 }
330 
331 /// addLiveIn - Add the specified physical register as a live-in value and
332 /// create a corresponding virtual register for it.
333 unsigned MachineFunction::addLiveIn(unsigned PReg,
334                                     const TargetRegisterClass *RC) {
335   assert(RC->contains(PReg) && "Not the correct regclass!");
336   unsigned VReg = getRegInfo().createVirtualRegister(RC);
337   getRegInfo().addLiveIn(PReg, VReg);
338   return VReg;
339 }
340 
341 /// getOrCreateDebugLocID - Look up the DebugLocTuple index with the given
342 /// source file, line, and column. If none currently exists, create a new
343 /// DebugLocTuple, and insert it into the DebugIdMap.
344 unsigned MachineFunction::getOrCreateDebugLocID(GlobalVariable *CompileUnit,
345                                                 unsigned Line, unsigned Col) {
346   DebugLocTuple Tuple(CompileUnit, Line, Col);
347   DenseMap<DebugLocTuple, unsigned>::iterator II
348     = DebugLocInfo.DebugIdMap.find(Tuple);
349   if (II != DebugLocInfo.DebugIdMap.end())
350     return II->second;
351   // Add a new tuple.
352   unsigned Id = DebugLocInfo.DebugLocations.size();
353   DebugLocInfo.DebugLocations.push_back(Tuple);
354   DebugLocInfo.DebugIdMap[Tuple] = Id;
355   return Id;
356 }
357 
358 /// getDebugLocTuple - Get the DebugLocTuple for a given DebugLoc object.
359 DebugLocTuple MachineFunction::getDebugLocTuple(DebugLoc DL) const {
360   unsigned Idx = DL.getIndex();
361   assert(Idx < DebugLocInfo.DebugLocations.size() &&
362          "Invalid index into debug locations!");
363   return DebugLocInfo.DebugLocations[Idx];
364 }
365 
366 //===----------------------------------------------------------------------===//
367 //  MachineFrameInfo implementation
368 //===----------------------------------------------------------------------===//
369 
370 /// CreateFixedObject - Create a new object at a fixed location on the stack.
371 /// All fixed objects should be created before other objects are created for
372 /// efficiency. By default, fixed objects are immutable. This returns an
373 /// index with a negative value.
374 ///
375 int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset,
376                                         bool Immutable) {
377   assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
378   Objects.insert(Objects.begin(), StackObject(Size, 1, SPOffset, Immutable));
379   return -++NumFixedObjects;
380 }
381 
382 
383 void MachineFrameInfo::print(const MachineFunction &MF, std::ostream &OS) const{
384   const TargetFrameInfo *FI = MF.getTarget().getFrameInfo();
385   int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0);
386 
387   for (unsigned i = 0, e = Objects.size(); i != e; ++i) {
388     const StackObject &SO = Objects[i];
389     OS << "  <fi#" << (int)(i-NumFixedObjects) << ">: ";
390     if (SO.Size == ~0ULL) {
391       OS << "dead\n";
392       continue;
393     }
394     if (SO.Size == 0)
395       OS << "variable sized";
396     else
397       OS << "size is " << SO.Size << " byte" << (SO.Size != 1 ? "s," : ",");
398     OS << " alignment is " << SO.Alignment << " byte"
399        << (SO.Alignment != 1 ? "s," : ",");
400 
401     if (i < NumFixedObjects)
402       OS << " fixed";
403     if (i < NumFixedObjects || SO.SPOffset != -1) {
404       int64_t Off = SO.SPOffset - ValOffset;
405       OS << " at location [SP";
406       if (Off > 0)
407         OS << "+" << Off;
408       else if (Off < 0)
409         OS << Off;
410       OS << "]";
411     }
412     OS << "\n";
413   }
414 
415   if (HasVarSizedObjects)
416     OS << "  Stack frame contains variable sized objects\n";
417 }
418 
419 void MachineFrameInfo::dump(const MachineFunction &MF) const {
420   print(MF, *cerr.stream());
421 }
422 
423 
424 //===----------------------------------------------------------------------===//
425 //  MachineJumpTableInfo implementation
426 //===----------------------------------------------------------------------===//
427 
428 /// getJumpTableIndex - Create a new jump table entry in the jump table info
429 /// or return an existing one.
430 ///
431 unsigned MachineJumpTableInfo::getJumpTableIndex(
432                                const std::vector<MachineBasicBlock*> &DestBBs) {
433   assert(!DestBBs.empty() && "Cannot create an empty jump table!");
434   for (unsigned i = 0, e = JumpTables.size(); i != e; ++i)
435     if (JumpTables[i].MBBs == DestBBs)
436       return i;
437 
438   JumpTables.push_back(MachineJumpTableEntry(DestBBs));
439   return JumpTables.size()-1;
440 }
441 
442 /// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update
443 /// the jump tables to branch to New instead.
444 bool
445 MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old,
446                                              MachineBasicBlock *New) {
447   assert(Old != New && "Not making a change?");
448   bool MadeChange = false;
449   for (size_t i = 0, e = JumpTables.size(); i != e; ++i) {
450     MachineJumpTableEntry &JTE = JumpTables[i];
451     for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j)
452       if (JTE.MBBs[j] == Old) {
453         JTE.MBBs[j] = New;
454         MadeChange = true;
455       }
456   }
457   return MadeChange;
458 }
459 
460 void MachineJumpTableInfo::print(std::ostream &OS) const {
461   // FIXME: this is lame, maybe we could print out the MBB numbers or something
462   // like {1, 2, 4, 5, 3, 0}
463   for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) {
464     OS << "  <jt#" << i << "> has " << JumpTables[i].MBBs.size()
465        << " entries\n";
466   }
467 }
468 
469 void MachineJumpTableInfo::dump() const { print(*cerr.stream()); }
470 
471 
472 //===----------------------------------------------------------------------===//
473 //  MachineConstantPool implementation
474 //===----------------------------------------------------------------------===//
475 
476 const Type *MachineConstantPoolEntry::getType() const {
477   if (isMachineConstantPoolEntry())
478     return Val.MachineCPVal->getType();
479   return Val.ConstVal->getType();
480 }
481 
482 
483 unsigned MachineConstantPoolEntry::getRelocationInfo() const {
484   if (isMachineConstantPoolEntry())
485     return Val.MachineCPVal->getRelocationInfo();
486   return Val.ConstVal->getRelocationInfo();
487 }
488 
489 MachineConstantPool::~MachineConstantPool() {
490   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
491     if (Constants[i].isMachineConstantPoolEntry())
492       delete Constants[i].Val.MachineCPVal;
493 }
494 
495 /// getConstantPoolIndex - Create a new entry in the constant pool or return
496 /// an existing one.  User must specify the log2 of the minimum required
497 /// alignment for the object.
498 ///
499 unsigned MachineConstantPool::getConstantPoolIndex(Constant *C,
500                                                    unsigned Alignment) {
501   assert(Alignment && "Alignment must be specified!");
502   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
503 
504   // Check to see if we already have this constant.
505   //
506   // FIXME, this could be made much more efficient for large constant pools.
507   for (unsigned i = 0, e = Constants.size(); i != e; ++i)
508     if (Constants[i].Val.ConstVal == C &&
509         (Constants[i].getAlignment() & (Alignment - 1)) == 0)
510       return i;
511 
512   Constants.push_back(MachineConstantPoolEntry(C, Alignment));
513   return Constants.size()-1;
514 }
515 
516 unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V,
517                                                    unsigned Alignment) {
518   assert(Alignment && "Alignment must be specified!");
519   if (Alignment > PoolAlignment) PoolAlignment = Alignment;
520 
521   // Check to see if we already have this constant.
522   //
523   // FIXME, this could be made much more efficient for large constant pools.
524   int Idx = V->getExistingMachineCPValue(this, Alignment);
525   if (Idx != -1)
526     return (unsigned)Idx;
527 
528   Constants.push_back(MachineConstantPoolEntry(V, Alignment));
529   return Constants.size()-1;
530 }
531 
532 void MachineConstantPool::print(raw_ostream &OS) const {
533   for (unsigned i = 0, e = Constants.size(); i != e; ++i) {
534     OS << "  <cp#" << i << "> is";
535     if (Constants[i].isMachineConstantPoolEntry())
536       Constants[i].Val.MachineCPVal->print(OS);
537     else
538       OS << *(Value*)Constants[i].Val.ConstVal;
539     OS << " , alignment=" << Constants[i].getAlignment();
540     OS << "\n";
541   }
542 }
543 
544 void MachineConstantPool::dump() const { print(errs()); }
545