MachineModuleInfo.cpp revision 262c21b60c0f6fbb2746b73fcb351ead873aefc1 
1//===-- llvm/CodeGen/MachineModuleInfo.cpp ----------------------*- C++ -*-===//
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#include "llvm/CodeGen/MachineModuleInfo.h"
11
12#include "llvm/Constants.h"
13#include "llvm/DerivedTypes.h"
14#include "llvm/GlobalVariable.h"
15#include "llvm/Intrinsics.h"
16#include "llvm/Instructions.h"
17#include "llvm/Module.h"
18#include "llvm/Analysis/ValueTracking.h"
19#include "llvm/CodeGen/MachineFunctionPass.h"
20#include "llvm/CodeGen/MachineFunction.h"
21#include "llvm/CodeGen/Passes.h"
22#include "llvm/Target/TargetInstrInfo.h"
23#include "llvm/Target/TargetMachine.h"
24#include "llvm/Target/TargetOptions.h"
25#include "llvm/MC/MCSymbol.h"
26#include "llvm/ADT/PointerUnion.h"
27#include "llvm/Support/Dwarf.h"
28#include "llvm/Support/ErrorHandling.h"
29using namespace llvm;
30using namespace llvm::dwarf;
31
32// Handle the Pass registration stuff necessary to use TargetData's.
33static RegisterPass<MachineModuleInfo>
34X("machinemoduleinfo", "Machine Module Information");
35char MachineModuleInfo::ID = 0;
36
37// Out of line virtual method.
38MachineModuleInfoImpl::~MachineModuleInfoImpl() {}
39
40namespace llvm {
41class MMIAddrLabelMapCallbackPtr : CallbackVH {
42  MMIAddrLabelMap *Map;
43public:
44  MMIAddrLabelMapCallbackPtr() : Map(0) {}
45  MMIAddrLabelMapCallbackPtr(Value *V) : CallbackVH(V), Map(0) {}
46
47  void setPtr(BasicBlock *BB) {
48    ValueHandleBase::operator=(BB);
49  }
50
51  void setMap(MMIAddrLabelMap *map) { Map = map; }
52
53  virtual void deleted();
54  virtual void allUsesReplacedWith(Value *V2);
55};
56
57class MMIAddrLabelMap {
58  MCContext &Context;
59  struct AddrLabelSymEntry {
60    /// Symbols - The symbols for the label.  This is a pointer union that is
61    /// either one symbol (the common case) or a list of symbols.
62    PointerUnion<MCSymbol *, std::vector<MCSymbol*>*> Symbols;
63
64    Function *Fn;   // The containing function of the BasicBlock.
65    unsigned Index; // The index in BBCallbacks for the BasicBlock.
66  };
67
68  DenseMap<AssertingVH<BasicBlock>, AddrLabelSymEntry> AddrLabelSymbols;
69
70  /// BBCallbacks - Callbacks for the BasicBlock's that we have entries for.  We
71  /// use this so we get notified if a block is deleted or RAUWd.
72  std::vector<MMIAddrLabelMapCallbackPtr> BBCallbacks;
73
74  /// DeletedAddrLabelsNeedingEmission - This is a per-function list of symbols
75  /// whose corresponding BasicBlock got deleted.  These symbols need to be
76  /// emitted at some point in the file, so AsmPrinter emits them after the
77  /// function body.
78  DenseMap<AssertingVH<Function>, std::vector<MCSymbol*> >
79    DeletedAddrLabelsNeedingEmission;
80public:
81
82  MMIAddrLabelMap(MCContext &context) : Context(context) {}
83  ~MMIAddrLabelMap() {
84    assert(DeletedAddrLabelsNeedingEmission.empty() &&
85           "Some labels for deleted blocks never got emitted");
86
87    // Deallocate any of the 'list of symbols' case.
88    for (DenseMap<AssertingVH<BasicBlock>, AddrLabelSymEntry>::iterator
89         I = AddrLabelSymbols.begin(), E = AddrLabelSymbols.end(); I != E; ++I)
90      if (I->second.Symbols.is<std::vector<MCSymbol*>*>())
91        delete I->second.Symbols.get<std::vector<MCSymbol*>*>();
92  }
93
94  MCSymbol *getAddrLabelSymbol(BasicBlock *BB);
95  std::vector<MCSymbol*> getAddrLabelSymbolToEmit(BasicBlock *BB);
96
97  void takeDeletedSymbolsForFunction(Function *F,
98                                     std::vector<MCSymbol*> &Result);
99
100  void UpdateForDeletedBlock(BasicBlock *BB);
101  void UpdateForRAUWBlock(BasicBlock *Old, BasicBlock *New);
102};
103}
104
105MCSymbol *MMIAddrLabelMap::getAddrLabelSymbol(BasicBlock *BB) {
106  assert(BB->hasAddressTaken() &&
107         "Shouldn't get label for block without address taken");
108  AddrLabelSymEntry &Entry = AddrLabelSymbols[BB];
109
110  // If we already had an entry for this block, just return it.
111  if (!Entry.Symbols.isNull()) {
112    assert(BB->getParent() == Entry.Fn && "Parent changed");
113    if (Entry.Symbols.is<MCSymbol*>())
114      return Entry.Symbols.get<MCSymbol*>();
115    return (*Entry.Symbols.get<std::vector<MCSymbol*>*>())[0];
116  }
117
118  // Otherwise, this is a new entry, create a new symbol for it and add an
119  // entry to BBCallbacks so we can be notified if the BB is deleted or RAUWd.
120  BBCallbacks.push_back(BB);
121  BBCallbacks.back().setMap(this);
122  Entry.Index = BBCallbacks.size()-1;
123  Entry.Fn = BB->getParent();
124  MCSymbol *Result = Context.CreateTempSymbol();
125  Entry.Symbols = Result;
126  return Result;
127}
128
129std::vector<MCSymbol*>
130MMIAddrLabelMap::getAddrLabelSymbolToEmit(BasicBlock *BB) {
131  assert(BB->hasAddressTaken() &&
132         "Shouldn't get label for block without address taken");
133  AddrLabelSymEntry &Entry = AddrLabelSymbols[BB];
134
135  std::vector<MCSymbol*> Result;
136
137  // If we already had an entry for this block, just return it.
138  if (Entry.Symbols.isNull())
139    Result.push_back(getAddrLabelSymbol(BB));
140  else if (MCSymbol *Sym = Entry.Symbols.dyn_cast<MCSymbol*>())
141    Result.push_back(Sym);
142  else
143    Result = *Entry.Symbols.get<std::vector<MCSymbol*>*>();
144  return Result;
145}
146
147
148/// takeDeletedSymbolsForFunction - If we have any deleted symbols for F, return
149/// them.
150void MMIAddrLabelMap::
151takeDeletedSymbolsForFunction(Function *F, std::vector<MCSymbol*> &Result) {
152  DenseMap<AssertingVH<Function>, std::vector<MCSymbol*> >::iterator I =
153    DeletedAddrLabelsNeedingEmission.find(F);
154
155  // If there are no entries for the function, just return.
156  if (I == DeletedAddrLabelsNeedingEmission.end()) return;
157
158  // Otherwise, take the list.
159  std::swap(Result, I->second);
160  DeletedAddrLabelsNeedingEmission.erase(I);
161}
162
163
164void MMIAddrLabelMap::UpdateForDeletedBlock(BasicBlock *BB) {
165  // If the block got deleted, there is no need for the symbol.  If the symbol
166  // was already emitted, we can just forget about it, otherwise we need to
167  // queue it up for later emission when the function is output.
168  AddrLabelSymEntry Entry = AddrLabelSymbols[BB];
169  AddrLabelSymbols.erase(BB);
170  assert(!Entry.Symbols.isNull() && "Didn't have a symbol, why a callback?");
171  BBCallbacks[Entry.Index] = 0;  // Clear the callback.
172
173  assert((BB->getParent() == 0 || BB->getParent() == Entry.Fn) &&
174         "Block/parent mismatch");
175
176  // Handle both the single and the multiple symbols cases.
177  if (MCSymbol *Sym = Entry.Symbols.dyn_cast<MCSymbol*>()) {
178    if (Sym->isDefined())
179      return;
180
181    // If the block is not yet defined, we need to emit it at the end of the
182    // function.  Add the symbol to the DeletedAddrLabelsNeedingEmission list
183    // for the containing Function.  Since the block is being deleted, its
184    // parent may already be removed, we have to get the function from 'Entry'.
185    DeletedAddrLabelsNeedingEmission[Entry.Fn].push_back(Sym);
186  } else {
187    std::vector<MCSymbol*> *Syms = Entry.Symbols.get<std::vector<MCSymbol*>*>();
188
189    for (unsigned i = 0, e = Syms->size(); i != e; ++i) {
190      MCSymbol *Sym = (*Syms)[i];
191      if (Sym->isDefined()) continue;  // Ignore already emitted labels.
192
193      // If the block is not yet defined, we need to emit it at the end of the
194      // function.  Add the symbol to the DeletedAddrLabelsNeedingEmission list
195      // for the containing Function.  Since the block is being deleted, its
196      // parent may already be removed, we have to get the function from
197      // 'Entry'.
198      DeletedAddrLabelsNeedingEmission[Entry.Fn].push_back(Sym);
199    }
200
201    // The entry is deleted, free the memory associated with the symbol list.
202    delete Syms;
203  }
204}
205
206void MMIAddrLabelMap::UpdateForRAUWBlock(BasicBlock *Old, BasicBlock *New) {
207  // Get the entry for the RAUW'd block and remove it from our map.
208  AddrLabelSymEntry OldEntry = AddrLabelSymbols[Old];
209  AddrLabelSymbols.erase(Old);
210  assert(!OldEntry.Symbols.isNull() && "Didn't have a symbol, why a callback?");
211
212  AddrLabelSymEntry &NewEntry = AddrLabelSymbols[New];
213
214  // If New is not address taken, just move our symbol over to it.
215  if (NewEntry.Symbols.isNull()) {
216    BBCallbacks[OldEntry.Index].setPtr(New);    // Update the callback.
217    NewEntry = OldEntry;     // Set New's entry.
218    return;
219  }
220
221  BBCallbacks[OldEntry.Index] = 0;    // Update the callback.
222
223  // Otherwise, we need to add the old symbol to the new block's set.  If it is
224  // just a single entry, upgrade it to a symbol list.
225  if (MCSymbol *PrevSym = NewEntry.Symbols.dyn_cast<MCSymbol*>()) {
226    std::vector<MCSymbol*> *SymList = new std::vector<MCSymbol*>();
227    SymList->push_back(PrevSym);
228    NewEntry.Symbols = SymList;
229  }
230
231  std::vector<MCSymbol*> *SymList =
232    NewEntry.Symbols.get<std::vector<MCSymbol*>*>();
233
234  // If the old entry was a single symbol, add it.
235  if (MCSymbol *Sym = OldEntry.Symbols.dyn_cast<MCSymbol*>()) {
236    SymList->push_back(Sym);
237    return;
238  }
239
240  // Otherwise, concatenate the list.
241  std::vector<MCSymbol*> *Syms =OldEntry.Symbols.get<std::vector<MCSymbol*>*>();
242  SymList->insert(SymList->end(), Syms->begin(), Syms->end());
243  delete Syms;
244}
245
246
247void MMIAddrLabelMapCallbackPtr::deleted() {
248  Map->UpdateForDeletedBlock(cast<BasicBlock>(getValPtr()));
249}
250
251void MMIAddrLabelMapCallbackPtr::allUsesReplacedWith(Value *V2) {
252  Map->UpdateForRAUWBlock(cast<BasicBlock>(getValPtr()), cast<BasicBlock>(V2));
253}
254
255
256//===----------------------------------------------------------------------===//
257
258MachineModuleInfo::MachineModuleInfo(const MCAsmInfo &MAI)
259: ImmutablePass(&ID), Context(MAI),
260  ObjFileMMI(0),
261  CurCallSite(0), CallsEHReturn(0), CallsUnwindInit(0), DbgInfoAvailable(false){
262  // Always emit some info, by default "no personality" info.
263  Personalities.push_back(NULL);
264  AddrLabelSymbols = 0;
265  TheModule = 0;
266}
267
268MachineModuleInfo::MachineModuleInfo()
269: ImmutablePass(&ID), Context(*(MCAsmInfo*)0) {
270  assert(0 && "This MachineModuleInfo constructor should never be called, MMI "
271         "should always be explicitly constructed by LLVMTargetMachine");
272  abort();
273}
274
275MachineModuleInfo::~MachineModuleInfo() {
276  delete ObjFileMMI;
277
278  // FIXME: Why isn't doFinalization being called??
279  //assert(AddrLabelSymbols == 0 && "doFinalization not called");
280  delete AddrLabelSymbols;
281  AddrLabelSymbols = 0;
282}
283
284/// doInitialization - Initialize the state for a new module.
285///
286bool MachineModuleInfo::doInitialization() {
287  assert(AddrLabelSymbols == 0 && "Improperly initialized");
288  return false;
289}
290
291/// doFinalization - Tear down the state after completion of a module.
292///
293bool MachineModuleInfo::doFinalization() {
294  delete AddrLabelSymbols;
295  AddrLabelSymbols = 0;
296  return false;
297}
298
299/// EndFunction - Discard function meta information.
300///
301void MachineModuleInfo::EndFunction() {
302  // Clean up frame info.
303  FrameMoves.clear();
304
305  // Clean up exception info.
306  LandingPads.clear();
307  CallSiteMap.clear();
308  TypeInfos.clear();
309  FilterIds.clear();
310  FilterEnds.clear();
311  CallsEHReturn = 0;
312  CallsUnwindInit = 0;
313  VariableDbgInfo.clear();
314}
315
316/// AnalyzeModule - Scan the module for global debug information.
317///
318void MachineModuleInfo::AnalyzeModule(Module &M) {
319  // Insert functions in the llvm.used array (but not llvm.compiler.used) into
320  // UsedFunctions.
321  GlobalVariable *GV = M.getGlobalVariable("llvm.used");
322  if (!GV || !GV->hasInitializer()) return;
323
324  // Should be an array of 'i8*'.
325  ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
326  if (InitList == 0) return;
327
328  for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i)
329    if (Function *F =
330          dyn_cast<Function>(InitList->getOperand(i)->stripPointerCasts()))
331      UsedFunctions.insert(F);
332}
333
334//===- Address of Block Management ----------------------------------------===//
335
336
337/// getAddrLabelSymbol - Return the symbol to be used for the specified basic
338/// block when its address is taken.  This cannot be its normal LBB label
339/// because the block may be accessed outside its containing function.
340MCSymbol *MachineModuleInfo::getAddrLabelSymbol(const BasicBlock *BB) {
341  // Lazily create AddrLabelSymbols.
342  if (AddrLabelSymbols == 0)
343    AddrLabelSymbols = new MMIAddrLabelMap(Context);
344  return AddrLabelSymbols->getAddrLabelSymbol(const_cast<BasicBlock*>(BB));
345}
346
347/// getAddrLabelSymbolToEmit - Return the symbol to be used for the specified
348/// basic block when its address is taken.  If other blocks were RAUW'd to
349/// this one, we may have to emit them as well, return the whole set.
350std::vector<MCSymbol*> MachineModuleInfo::
351getAddrLabelSymbolToEmit(const BasicBlock *BB) {
352  // Lazily create AddrLabelSymbols.
353  if (AddrLabelSymbols == 0)
354    AddrLabelSymbols = new MMIAddrLabelMap(Context);
355 return AddrLabelSymbols->getAddrLabelSymbolToEmit(const_cast<BasicBlock*>(BB));
356}
357
358
359/// takeDeletedSymbolsForFunction - If the specified function has had any
360/// references to address-taken blocks generated, but the block got deleted,
361/// return the symbol now so we can emit it.  This prevents emitting a
362/// reference to a symbol that has no definition.
363void MachineModuleInfo::
364takeDeletedSymbolsForFunction(const Function *F,
365                              std::vector<MCSymbol*> &Result) {
366  // If no blocks have had their addresses taken, we're done.
367  if (AddrLabelSymbols == 0) return;
368  return AddrLabelSymbols->
369     takeDeletedSymbolsForFunction(const_cast<Function*>(F), Result);
370}
371
372//===- EH -----------------------------------------------------------------===//
373
374/// getOrCreateLandingPadInfo - Find or create an LandingPadInfo for the
375/// specified MachineBasicBlock.
376LandingPadInfo &MachineModuleInfo::getOrCreateLandingPadInfo
377    (MachineBasicBlock *LandingPad) {
378  unsigned N = LandingPads.size();
379  for (unsigned i = 0; i < N; ++i) {
380    LandingPadInfo &LP = LandingPads[i];
381    if (LP.LandingPadBlock == LandingPad)
382      return LP;
383  }
384
385  LandingPads.push_back(LandingPadInfo(LandingPad));
386  return LandingPads[N];
387}
388
389/// addInvoke - Provide the begin and end labels of an invoke style call and
390/// associate it with a try landing pad block.
391void MachineModuleInfo::addInvoke(MachineBasicBlock *LandingPad,
392                                  MCSymbol *BeginLabel, MCSymbol *EndLabel) {
393  LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
394  LP.BeginLabels.push_back(BeginLabel);
395  LP.EndLabels.push_back(EndLabel);
396}
397
398/// addLandingPad - Provide the label of a try LandingPad block.
399///
400MCSymbol *MachineModuleInfo::addLandingPad(MachineBasicBlock *LandingPad) {
401  MCSymbol *LandingPadLabel = Context.CreateTempSymbol();
402  LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
403  LP.LandingPadLabel = LandingPadLabel;
404  return LandingPadLabel;
405}
406
407/// addPersonality - Provide the personality function for the exception
408/// information.
409void MachineModuleInfo::addPersonality(MachineBasicBlock *LandingPad,
410                                       Function *Personality) {
411  LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
412  LP.Personality = Personality;
413
414  for (unsigned i = 0; i < Personalities.size(); ++i)
415    if (Personalities[i] == Personality)
416      return;
417
418  // If this is the first personality we're adding go
419  // ahead and add it at the beginning.
420  if (Personalities[0] == NULL)
421    Personalities[0] = Personality;
422  else
423    Personalities.push_back(Personality);
424}
425
426/// addCatchTypeInfo - Provide the catch typeinfo for a landing pad.
427///
428void MachineModuleInfo::addCatchTypeInfo(MachineBasicBlock *LandingPad,
429                                        std::vector<GlobalVariable *> &TyInfo) {
430  LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
431  for (unsigned N = TyInfo.size(); N; --N)
432    LP.TypeIds.push_back(getTypeIDFor(TyInfo[N - 1]));
433}
434
435/// addFilterTypeInfo - Provide the filter typeinfo for a landing pad.
436///
437void MachineModuleInfo::addFilterTypeInfo(MachineBasicBlock *LandingPad,
438                                        std::vector<GlobalVariable *> &TyInfo) {
439  LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
440  std::vector<unsigned> IdsInFilter(TyInfo.size());
441  for (unsigned I = 0, E = TyInfo.size(); I != E; ++I)
442    IdsInFilter[I] = getTypeIDFor(TyInfo[I]);
443  LP.TypeIds.push_back(getFilterIDFor(IdsInFilter));
444}
445
446/// addCleanup - Add a cleanup action for a landing pad.
447///
448void MachineModuleInfo::addCleanup(MachineBasicBlock *LandingPad) {
449  LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
450  LP.TypeIds.push_back(0);
451}
452
453/// TidyLandingPads - Remap landing pad labels and remove any deleted landing
454/// pads.
455void MachineModuleInfo::TidyLandingPads() {
456  for (unsigned i = 0; i != LandingPads.size(); ) {
457    LandingPadInfo &LandingPad = LandingPads[i];
458    if (LandingPad.LandingPadLabel && !LandingPad.LandingPadLabel->isDefined())
459      LandingPad.LandingPadLabel = 0;
460
461    // Special case: we *should* emit LPs with null LP MBB. This indicates
462    // "nounwind" case.
463    if (!LandingPad.LandingPadLabel && LandingPad.LandingPadBlock) {
464      LandingPads.erase(LandingPads.begin() + i);
465      continue;
466    }
467
468    for (unsigned j = 0, e = LandingPads[i].BeginLabels.size(); j != e; ++j) {
469      MCSymbol *BeginLabel = LandingPad.BeginLabels[j];
470      MCSymbol *EndLabel = LandingPad.EndLabels[j];
471      if (BeginLabel->isDefined() && EndLabel->isDefined()) continue;
472
473      LandingPad.BeginLabels.erase(LandingPad.BeginLabels.begin() + j);
474      LandingPad.EndLabels.erase(LandingPad.EndLabels.begin() + j);
475      --j, --e;
476    }
477
478    // Remove landing pads with no try-ranges.
479    if (LandingPads[i].BeginLabels.empty()) {
480      LandingPads.erase(LandingPads.begin() + i);
481      continue;
482    }
483
484    // If there is no landing pad, ensure that the list of typeids is empty.
485    // If the only typeid is a cleanup, this is the same as having no typeids.
486    if (!LandingPad.LandingPadBlock ||
487        (LandingPad.TypeIds.size() == 1 && !LandingPad.TypeIds[0]))
488      LandingPad.TypeIds.clear();
489    ++i;
490  }
491}
492
493/// getTypeIDFor - Return the type id for the specified typeinfo.  This is
494/// function wide.
495unsigned MachineModuleInfo::getTypeIDFor(GlobalVariable *TI) {
496  for (unsigned i = 0, N = TypeInfos.size(); i != N; ++i)
497    if (TypeInfos[i] == TI) return i + 1;
498
499  TypeInfos.push_back(TI);
500  return TypeInfos.size();
501}
502
503/// getFilterIDFor - Return the filter id for the specified typeinfos.  This is
504/// function wide.
505int MachineModuleInfo::getFilterIDFor(std::vector<unsigned> &TyIds) {
506  // If the new filter coincides with the tail of an existing filter, then
507  // re-use the existing filter.  Folding filters more than this requires
508  // re-ordering filters and/or their elements - probably not worth it.
509  for (std::vector<unsigned>::iterator I = FilterEnds.begin(),
510       E = FilterEnds.end(); I != E; ++I) {
511    unsigned i = *I, j = TyIds.size();
512
513    while (i && j)
514      if (FilterIds[--i] != TyIds[--j])
515        goto try_next;
516
517    if (!j)
518      // The new filter coincides with range [i, end) of the existing filter.
519      return -(1 + i);
520
521try_next:;
522  }
523
524  // Add the new filter.
525  int FilterID = -(1 + FilterIds.size());
526  FilterIds.reserve(FilterIds.size() + TyIds.size() + 1);
527  for (unsigned I = 0, N = TyIds.size(); I != N; ++I)
528    FilterIds.push_back(TyIds[I]);
529  FilterEnds.push_back(FilterIds.size());
530  FilterIds.push_back(0); // terminator
531  return FilterID;
532}
533
534/// getPersonality - Return the personality function for the current function.
535Function *MachineModuleInfo::getPersonality() const {
536  // FIXME: Until PR1414 will be fixed, we're using 1 personality function per
537  // function
538  return !LandingPads.empty() ? LandingPads[0].Personality : NULL;
539}
540
541/// getPersonalityIndex - Return unique index for current personality
542/// function. NULL/first personality function should always get zero index.
543unsigned MachineModuleInfo::getPersonalityIndex() const {
544  const Function* Personality = NULL;
545
546  // Scan landing pads. If there is at least one non-NULL personality - use it.
547  for (unsigned i = 0; i != LandingPads.size(); ++i)
548    if (LandingPads[i].Personality) {
549      Personality = LandingPads[i].Personality;
550      break;
551    }
552
553  for (unsigned i = 0; i < Personalities.size(); ++i) {
554    if (Personalities[i] == Personality)
555      return i;
556  }
557
558  // This will happen if the current personality function is
559  // in the zero index.
560  return 0;
561}
562
563