MachineModuleInfo.cpp revision a65d6a686e6ad865c61aec70c5bdfb30bf6f5b22 
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/Module.h"
16#include "llvm/Analysis/ValueTracking.h"
17#include "llvm/CodeGen/MachineFunctionPass.h"
18#include "llvm/CodeGen/MachineFunction.h"
19#include "llvm/CodeGen/Passes.h"
20#include "llvm/Target/TargetInstrInfo.h"
21#include "llvm/Target/TargetMachine.h"
22#include "llvm/Target/TargetOptions.h"
23#include "llvm/MC/MCSymbol.h"
24#include "llvm/ADT/PointerUnion.h"
25#include "llvm/Support/Dwarf.h"
26#include "llvm/Support/ErrorHandling.h"
27using namespace llvm;
28using namespace llvm::dwarf;
29
30// Handle the Pass registration stuff necessary to use TargetData's.
31INITIALIZE_PASS(MachineModuleInfo, "machinemoduleinfo",
32                "Machine Module Information", false, false)
33char MachineModuleInfo::ID = 0;
34
35// Out of line virtual method.
36MachineModuleInfoImpl::~MachineModuleInfoImpl() {}
37
38namespace llvm {
39class MMIAddrLabelMapCallbackPtr : CallbackVH {
40  MMIAddrLabelMap *Map;
41public:
42  MMIAddrLabelMapCallbackPtr() : Map(0) {}
43  MMIAddrLabelMapCallbackPtr(Value *V) : CallbackVH(V), Map(0) {}
44
45  void setPtr(BasicBlock *BB) {
46    ValueHandleBase::operator=(BB);
47  }
48
49  void setMap(MMIAddrLabelMap *map) { Map = map; }
50
51  virtual void deleted();
52  virtual void allUsesReplacedWith(Value *V2);
53};
54
55class MMIAddrLabelMap {
56  MCContext &Context;
57  struct AddrLabelSymEntry {
58    /// Symbols - The symbols for the label.  This is a pointer union that is
59    /// either one symbol (the common case) or a list of symbols.
60    PointerUnion<MCSymbol *, std::vector<MCSymbol*>*> Symbols;
61
62    Function *Fn;   // The containing function of the BasicBlock.
63    unsigned Index; // The index in BBCallbacks for the BasicBlock.
64  };
65
66  DenseMap<AssertingVH<BasicBlock>, AddrLabelSymEntry> AddrLabelSymbols;
67
68  /// BBCallbacks - Callbacks for the BasicBlock's that we have entries for.  We
69  /// use this so we get notified if a block is deleted or RAUWd.
70  std::vector<MMIAddrLabelMapCallbackPtr> BBCallbacks;
71
72  /// DeletedAddrLabelsNeedingEmission - This is a per-function list of symbols
73  /// whose corresponding BasicBlock got deleted.  These symbols need to be
74  /// emitted at some point in the file, so AsmPrinter emits them after the
75  /// function body.
76  DenseMap<AssertingVH<Function>, std::vector<MCSymbol*> >
77    DeletedAddrLabelsNeedingEmission;
78public:
79
80  MMIAddrLabelMap(MCContext &context) : Context(context) {}
81  ~MMIAddrLabelMap() {
82    assert(DeletedAddrLabelsNeedingEmission.empty() &&
83           "Some labels for deleted blocks never got emitted");
84
85    // Deallocate any of the 'list of symbols' case.
86    for (DenseMap<AssertingVH<BasicBlock>, AddrLabelSymEntry>::iterator
87         I = AddrLabelSymbols.begin(), E = AddrLabelSymbols.end(); I != E; ++I)
88      if (I->second.Symbols.is<std::vector<MCSymbol*>*>())
89        delete I->second.Symbols.get<std::vector<MCSymbol*>*>();
90  }
91
92  MCSymbol *getAddrLabelSymbol(BasicBlock *BB);
93  std::vector<MCSymbol*> getAddrLabelSymbolToEmit(BasicBlock *BB);
94
95  void takeDeletedSymbolsForFunction(Function *F,
96                                     std::vector<MCSymbol*> &Result);
97
98  void UpdateForDeletedBlock(BasicBlock *BB);
99  void UpdateForRAUWBlock(BasicBlock *Old, BasicBlock *New);
100};
101}
102
103MCSymbol *MMIAddrLabelMap::getAddrLabelSymbol(BasicBlock *BB) {
104  assert(BB->hasAddressTaken() &&
105         "Shouldn't get label for block without address taken");
106  AddrLabelSymEntry &Entry = AddrLabelSymbols[BB];
107
108  // If we already had an entry for this block, just return it.
109  if (!Entry.Symbols.isNull()) {
110    assert(BB->getParent() == Entry.Fn && "Parent changed");
111    if (Entry.Symbols.is<MCSymbol*>())
112      return Entry.Symbols.get<MCSymbol*>();
113    return (*Entry.Symbols.get<std::vector<MCSymbol*>*>())[0];
114  }
115
116  // Otherwise, this is a new entry, create a new symbol for it and add an
117  // entry to BBCallbacks so we can be notified if the BB is deleted or RAUWd.
118  BBCallbacks.push_back(BB);
119  BBCallbacks.back().setMap(this);
120  Entry.Index = BBCallbacks.size()-1;
121  Entry.Fn = BB->getParent();
122  MCSymbol *Result = Context.CreateTempSymbol();
123  Entry.Symbols = Result;
124  return Result;
125}
126
127std::vector<MCSymbol*>
128MMIAddrLabelMap::getAddrLabelSymbolToEmit(BasicBlock *BB) {
129  assert(BB->hasAddressTaken() &&
130         "Shouldn't get label for block without address taken");
131  AddrLabelSymEntry &Entry = AddrLabelSymbols[BB];
132
133  std::vector<MCSymbol*> Result;
134
135  // If we already had an entry for this block, just return it.
136  if (Entry.Symbols.isNull())
137    Result.push_back(getAddrLabelSymbol(BB));
138  else if (MCSymbol *Sym = Entry.Symbols.dyn_cast<MCSymbol*>())
139    Result.push_back(Sym);
140  else
141    Result = *Entry.Symbols.get<std::vector<MCSymbol*>*>();
142  return Result;
143}
144
145
146/// takeDeletedSymbolsForFunction - If we have any deleted symbols for F, return
147/// them.
148void MMIAddrLabelMap::
149takeDeletedSymbolsForFunction(Function *F, std::vector<MCSymbol*> &Result) {
150  DenseMap<AssertingVH<Function>, std::vector<MCSymbol*> >::iterator I =
151    DeletedAddrLabelsNeedingEmission.find(F);
152
153  // If there are no entries for the function, just return.
154  if (I == DeletedAddrLabelsNeedingEmission.end()) return;
155
156  // Otherwise, take the list.
157  std::swap(Result, I->second);
158  DeletedAddrLabelsNeedingEmission.erase(I);
159}
160
161
162void MMIAddrLabelMap::UpdateForDeletedBlock(BasicBlock *BB) {
163  // If the block got deleted, there is no need for the symbol.  If the symbol
164  // was already emitted, we can just forget about it, otherwise we need to
165  // queue it up for later emission when the function is output.
166  AddrLabelSymEntry Entry = AddrLabelSymbols[BB];
167  AddrLabelSymbols.erase(BB);
168  assert(!Entry.Symbols.isNull() && "Didn't have a symbol, why a callback?");
169  BBCallbacks[Entry.Index] = 0;  // Clear the callback.
170
171  assert((BB->getParent() == 0 || BB->getParent() == Entry.Fn) &&
172         "Block/parent mismatch");
173
174  // Handle both the single and the multiple symbols cases.
175  if (MCSymbol *Sym = Entry.Symbols.dyn_cast<MCSymbol*>()) {
176    if (Sym->isDefined())
177      return;
178
179    // If the block is not yet defined, we need to emit it at the end of the
180    // function.  Add the symbol to the DeletedAddrLabelsNeedingEmission list
181    // for the containing Function.  Since the block is being deleted, its
182    // parent may already be removed, we have to get the function from 'Entry'.
183    DeletedAddrLabelsNeedingEmission[Entry.Fn].push_back(Sym);
184  } else {
185    std::vector<MCSymbol*> *Syms = Entry.Symbols.get<std::vector<MCSymbol*>*>();
186
187    for (unsigned i = 0, e = Syms->size(); i != e; ++i) {
188      MCSymbol *Sym = (*Syms)[i];
189      if (Sym->isDefined()) continue;  // Ignore already emitted labels.
190
191      // If the block is not yet defined, we need to emit it at the end of the
192      // function.  Add the symbol to the DeletedAddrLabelsNeedingEmission list
193      // for the containing Function.  Since the block is being deleted, its
194      // parent may already be removed, we have to get the function from
195      // 'Entry'.
196      DeletedAddrLabelsNeedingEmission[Entry.Fn].push_back(Sym);
197    }
198
199    // The entry is deleted, free the memory associated with the symbol list.
200    delete Syms;
201  }
202}
203
204void MMIAddrLabelMap::UpdateForRAUWBlock(BasicBlock *Old, BasicBlock *New) {
205  // Get the entry for the RAUW'd block and remove it from our map.
206  AddrLabelSymEntry OldEntry = AddrLabelSymbols[Old];
207  AddrLabelSymbols.erase(Old);
208  assert(!OldEntry.Symbols.isNull() && "Didn't have a symbol, why a callback?");
209
210  AddrLabelSymEntry &NewEntry = AddrLabelSymbols[New];
211
212  // If New is not address taken, just move our symbol over to it.
213  if (NewEntry.Symbols.isNull()) {
214    BBCallbacks[OldEntry.Index].setPtr(New);    // Update the callback.
215    NewEntry = OldEntry;     // Set New's entry.
216    return;
217  }
218
219  BBCallbacks[OldEntry.Index] = 0;    // Update the callback.
220
221  // Otherwise, we need to add the old symbol to the new block's set.  If it is
222  // just a single entry, upgrade it to a symbol list.
223  if (MCSymbol *PrevSym = NewEntry.Symbols.dyn_cast<MCSymbol*>()) {
224    std::vector<MCSymbol*> *SymList = new std::vector<MCSymbol*>();
225    SymList->push_back(PrevSym);
226    NewEntry.Symbols = SymList;
227  }
228
229  std::vector<MCSymbol*> *SymList =
230    NewEntry.Symbols.get<std::vector<MCSymbol*>*>();
231
232  // If the old entry was a single symbol, add it.
233  if (MCSymbol *Sym = OldEntry.Symbols.dyn_cast<MCSymbol*>()) {
234    SymList->push_back(Sym);
235    return;
236  }
237
238  // Otherwise, concatenate the list.
239  std::vector<MCSymbol*> *Syms =OldEntry.Symbols.get<std::vector<MCSymbol*>*>();
240  SymList->insert(SymList->end(), Syms->begin(), Syms->end());
241  delete Syms;
242}
243
244
245void MMIAddrLabelMapCallbackPtr::deleted() {
246  Map->UpdateForDeletedBlock(cast<BasicBlock>(getValPtr()));
247}
248
249void MMIAddrLabelMapCallbackPtr::allUsesReplacedWith(Value *V2) {
250  Map->UpdateForRAUWBlock(cast<BasicBlock>(getValPtr()), cast<BasicBlock>(V2));
251}
252
253
254//===----------------------------------------------------------------------===//
255
256MachineModuleInfo::MachineModuleInfo(const MCAsmInfo &MAI)
257: ImmutablePass(ID), Context(MAI),
258  ObjFileMMI(0),
259  CurCallSite(0), CallsEHReturn(0), CallsUnwindInit(0), DbgInfoAvailable(false),
260  CallsExternalFunctionWithFloatingPointArguments(false) {
261  initializeMachineModuleInfoPass(*PassRegistry::getPassRegistry());
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(const Module &M) {
319  // Insert functions in the llvm.used array (but not llvm.compiler.used) into
320  // UsedFunctions.
321  const GlobalVariable *GV = M.getGlobalVariable("llvm.used");
322  if (!GV || !GV->hasInitializer()) return;
323
324  // Should be an array of 'i8*'.
325  const 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 (const 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                                       const 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<const 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<const 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(DenseMap<MCSymbol*, uintptr_t> *LPMap) {
456  for (unsigned i = 0; i != LandingPads.size(); ) {
457    LandingPadInfo &LandingPad = LandingPads[i];
458    if (LandingPad.LandingPadLabel &&
459        !LandingPad.LandingPadLabel->isDefined() &&
460        (!LPMap || (*LPMap)[LandingPad.LandingPadLabel] == 0))
461      LandingPad.LandingPadLabel = 0;
462
463    // Special case: we *should* emit LPs with null LP MBB. This indicates
464    // "nounwind" case.
465    if (!LandingPad.LandingPadLabel && LandingPad.LandingPadBlock) {
466      LandingPads.erase(LandingPads.begin() + i);
467      continue;
468    }
469
470    for (unsigned j = 0, e = LandingPads[i].BeginLabels.size(); j != e; ++j) {
471      MCSymbol *BeginLabel = LandingPad.BeginLabels[j];
472      MCSymbol *EndLabel = LandingPad.EndLabels[j];
473      if ((BeginLabel->isDefined() ||
474           (LPMap && (*LPMap)[BeginLabel] != 0)) &&
475          (EndLabel->isDefined() ||
476           (LPMap && (*LPMap)[EndLabel] != 0))) continue;
477
478      LandingPad.BeginLabels.erase(LandingPad.BeginLabels.begin() + j);
479      LandingPad.EndLabels.erase(LandingPad.EndLabels.begin() + j);
480      --j, --e;
481    }
482
483    // Remove landing pads with no try-ranges.
484    if (LandingPads[i].BeginLabels.empty()) {
485      LandingPads.erase(LandingPads.begin() + i);
486      continue;
487    }
488
489    // If there is no landing pad, ensure that the list of typeids is empty.
490    // If the only typeid is a cleanup, this is the same as having no typeids.
491    if (!LandingPad.LandingPadBlock ||
492        (LandingPad.TypeIds.size() == 1 && !LandingPad.TypeIds[0]))
493      LandingPad.TypeIds.clear();
494    ++i;
495  }
496}
497
498/// getTypeIDFor - Return the type id for the specified typeinfo.  This is
499/// function wide.
500unsigned MachineModuleInfo::getTypeIDFor(const GlobalVariable *TI) {
501  for (unsigned i = 0, N = TypeInfos.size(); i != N; ++i)
502    if (TypeInfos[i] == TI) return i + 1;
503
504  TypeInfos.push_back(TI);
505  return TypeInfos.size();
506}
507
508/// getFilterIDFor - Return the filter id for the specified typeinfos.  This is
509/// function wide.
510int MachineModuleInfo::getFilterIDFor(std::vector<unsigned> &TyIds) {
511  // If the new filter coincides with the tail of an existing filter, then
512  // re-use the existing filter.  Folding filters more than this requires
513  // re-ordering filters and/or their elements - probably not worth it.
514  for (std::vector<unsigned>::iterator I = FilterEnds.begin(),
515       E = FilterEnds.end(); I != E; ++I) {
516    unsigned i = *I, j = TyIds.size();
517
518    while (i && j)
519      if (FilterIds[--i] != TyIds[--j])
520        goto try_next;
521
522    if (!j)
523      // The new filter coincides with range [i, end) of the existing filter.
524      return -(1 + i);
525
526try_next:;
527  }
528
529  // Add the new filter.
530  int FilterID = -(1 + FilterIds.size());
531  FilterIds.reserve(FilterIds.size() + TyIds.size() + 1);
532  for (unsigned I = 0, N = TyIds.size(); I != N; ++I)
533    FilterIds.push_back(TyIds[I]);
534  FilterEnds.push_back(FilterIds.size());
535  FilterIds.push_back(0); // terminator
536  return FilterID;
537}
538
539/// getPersonality - Return the personality function for the current function.
540const Function *MachineModuleInfo::getPersonality() const {
541  // FIXME: Until PR1414 will be fixed, we're using 1 personality function per
542  // function
543  return !LandingPads.empty() ? LandingPads[0].Personality : NULL;
544}
545
546/// getPersonalityIndex - Return unique index for current personality
547/// function. NULL/first personality function should always get zero index.
548unsigned MachineModuleInfo::getPersonalityIndex() const {
549  const Function* Personality = NULL;
550
551  // Scan landing pads. If there is at least one non-NULL personality - use it.
552  for (unsigned i = 0; i != LandingPads.size(); ++i)
553    if (LandingPads[i].Personality) {
554      Personality = LandingPads[i].Personality;
555      break;
556    }
557
558  for (unsigned i = 0; i < Personalities.size(); ++i) {
559    if (Personalities[i] == Personality)
560      return i;
561  }
562
563  // This will happen if the current personality function is
564  // in the zero index.
565  return 0;
566}
567