Function.cpp revision 36b56886974eae4f9c5ebc96befd3e7bfe5de338 
1//===-- Function.cpp - Implement the Global object classes ----------------===//
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// This file implements the Function class for the IR library.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/IR/Function.h"
15#include "LLVMContextImpl.h"
16#include "SymbolTableListTraitsImpl.h"
17#include "llvm/ADT/DenseMap.h"
18#include "llvm/ADT/STLExtras.h"
19#include "llvm/ADT/StringExtras.h"
20#include "llvm/CodeGen/ValueTypes.h"
21#include "llvm/IR/CallSite.h"
22#include "llvm/IR/DerivedTypes.h"
23#include "llvm/IR/InstIterator.h"
24#include "llvm/IR/IntrinsicInst.h"
25#include "llvm/IR/LLVMContext.h"
26#include "llvm/IR/LeakDetector.h"
27#include "llvm/IR/Module.h"
28#include "llvm/Support/ManagedStatic.h"
29#include "llvm/Support/RWMutex.h"
30#include "llvm/Support/StringPool.h"
31#include "llvm/Support/Threading.h"
32using namespace llvm;
33
34// Explicit instantiations of SymbolTableListTraits since some of the methods
35// are not in the public header file...
36template class llvm::SymbolTableListTraits<Argument, Function>;
37template class llvm::SymbolTableListTraits<BasicBlock, Function>;
38
39//===----------------------------------------------------------------------===//
40// Argument Implementation
41//===----------------------------------------------------------------------===//
42
43void Argument::anchor() { }
44
45Argument::Argument(Type *Ty, const Twine &Name, Function *Par)
46  : Value(Ty, Value::ArgumentVal) {
47  Parent = 0;
48
49  // Make sure that we get added to a function
50  LeakDetector::addGarbageObject(this);
51
52  if (Par)
53    Par->getArgumentList().push_back(this);
54  setName(Name);
55}
56
57void Argument::setParent(Function *parent) {
58  if (getParent())
59    LeakDetector::addGarbageObject(this);
60  Parent = parent;
61  if (getParent())
62    LeakDetector::removeGarbageObject(this);
63}
64
65/// getArgNo - Return the index of this formal argument in its containing
66/// function.  For example in "void foo(int a, float b)" a is 0 and b is 1.
67unsigned Argument::getArgNo() const {
68  const Function *F = getParent();
69  assert(F && "Argument is not in a function");
70
71  Function::const_arg_iterator AI = F->arg_begin();
72  unsigned ArgIdx = 0;
73  for (; &*AI != this; ++AI)
74    ++ArgIdx;
75
76  return ArgIdx;
77}
78
79/// hasByValAttr - Return true if this argument has the byval attribute on it
80/// in its containing function.
81bool Argument::hasByValAttr() const {
82  if (!getType()->isPointerTy()) return false;
83  return getParent()->getAttributes().
84    hasAttribute(getArgNo()+1, Attribute::ByVal);
85}
86
87/// \brief Return true if this argument has the inalloca attribute on it in
88/// its containing function.
89bool Argument::hasInAllocaAttr() const {
90  if (!getType()->isPointerTy()) return false;
91  return getParent()->getAttributes().
92    hasAttribute(getArgNo()+1, Attribute::InAlloca);
93}
94
95bool Argument::hasByValOrInAllocaAttr() const {
96  if (!getType()->isPointerTy()) return false;
97  AttributeSet Attrs = getParent()->getAttributes();
98  return Attrs.hasAttribute(getArgNo() + 1, Attribute::ByVal) ||
99         Attrs.hasAttribute(getArgNo() + 1, Attribute::InAlloca);
100}
101
102unsigned Argument::getParamAlignment() const {
103  assert(getType()->isPointerTy() && "Only pointers have alignments");
104  return getParent()->getParamAlignment(getArgNo()+1);
105
106}
107
108/// hasNestAttr - Return true if this argument has the nest attribute on
109/// it in its containing function.
110bool Argument::hasNestAttr() const {
111  if (!getType()->isPointerTy()) return false;
112  return getParent()->getAttributes().
113    hasAttribute(getArgNo()+1, Attribute::Nest);
114}
115
116/// hasNoAliasAttr - Return true if this argument has the noalias attribute on
117/// it in its containing function.
118bool Argument::hasNoAliasAttr() const {
119  if (!getType()->isPointerTy()) return false;
120  return getParent()->getAttributes().
121    hasAttribute(getArgNo()+1, Attribute::NoAlias);
122}
123
124/// hasNoCaptureAttr - Return true if this argument has the nocapture attribute
125/// on it in its containing function.
126bool Argument::hasNoCaptureAttr() const {
127  if (!getType()->isPointerTy()) return false;
128  return getParent()->getAttributes().
129    hasAttribute(getArgNo()+1, Attribute::NoCapture);
130}
131
132/// hasSRetAttr - Return true if this argument has the sret attribute on
133/// it in its containing function.
134bool Argument::hasStructRetAttr() const {
135  if (!getType()->isPointerTy()) return false;
136  if (this != getParent()->arg_begin())
137    return false; // StructRet param must be first param
138  return getParent()->getAttributes().
139    hasAttribute(1, Attribute::StructRet);
140}
141
142/// hasReturnedAttr - Return true if this argument has the returned attribute on
143/// it in its containing function.
144bool Argument::hasReturnedAttr() const {
145  return getParent()->getAttributes().
146    hasAttribute(getArgNo()+1, Attribute::Returned);
147}
148
149/// Return true if this argument has the readonly or readnone attribute on it
150/// in its containing function.
151bool Argument::onlyReadsMemory() const {
152  return getParent()->getAttributes().
153      hasAttribute(getArgNo()+1, Attribute::ReadOnly) ||
154      getParent()->getAttributes().
155      hasAttribute(getArgNo()+1, Attribute::ReadNone);
156}
157
158/// addAttr - Add attributes to an argument.
159void Argument::addAttr(AttributeSet AS) {
160  assert(AS.getNumSlots() <= 1 &&
161         "Trying to add more than one attribute set to an argument!");
162  AttrBuilder B(AS, AS.getSlotIndex(0));
163  getParent()->addAttributes(getArgNo() + 1,
164                             AttributeSet::get(Parent->getContext(),
165                                               getArgNo() + 1, B));
166}
167
168/// removeAttr - Remove attributes from an argument.
169void Argument::removeAttr(AttributeSet AS) {
170  assert(AS.getNumSlots() <= 1 &&
171         "Trying to remove more than one attribute set from an argument!");
172  AttrBuilder B(AS, AS.getSlotIndex(0));
173  getParent()->removeAttributes(getArgNo() + 1,
174                                AttributeSet::get(Parent->getContext(),
175                                                  getArgNo() + 1, B));
176}
177
178//===----------------------------------------------------------------------===//
179// Helper Methods in Function
180//===----------------------------------------------------------------------===//
181
182LLVMContext &Function::getContext() const {
183  return getType()->getContext();
184}
185
186FunctionType *Function::getFunctionType() const {
187  return cast<FunctionType>(getType()->getElementType());
188}
189
190bool Function::isVarArg() const {
191  return getFunctionType()->isVarArg();
192}
193
194Type *Function::getReturnType() const {
195  return getFunctionType()->getReturnType();
196}
197
198void Function::removeFromParent() {
199  getParent()->getFunctionList().remove(this);
200}
201
202void Function::eraseFromParent() {
203  getParent()->getFunctionList().erase(this);
204}
205
206//===----------------------------------------------------------------------===//
207// Function Implementation
208//===----------------------------------------------------------------------===//
209
210Function::Function(FunctionType *Ty, LinkageTypes Linkage,
211                   const Twine &name, Module *ParentModule)
212  : GlobalValue(PointerType::getUnqual(Ty),
213                Value::FunctionVal, 0, 0, Linkage, name) {
214  assert(FunctionType::isValidReturnType(getReturnType()) &&
215         "invalid return type");
216  SymTab = new ValueSymbolTable();
217
218  // If the function has arguments, mark them as lazily built.
219  if (Ty->getNumParams())
220    setValueSubclassData(1);   // Set the "has lazy arguments" bit.
221
222  // Make sure that we get added to a function
223  LeakDetector::addGarbageObject(this);
224
225  if (ParentModule)
226    ParentModule->getFunctionList().push_back(this);
227
228  // Ensure intrinsics have the right parameter attributes.
229  if (unsigned IID = getIntrinsicID())
230    setAttributes(Intrinsic::getAttributes(getContext(), Intrinsic::ID(IID)));
231
232}
233
234Function::~Function() {
235  dropAllReferences();    // After this it is safe to delete instructions.
236
237  // Delete all of the method arguments and unlink from symbol table...
238  ArgumentList.clear();
239  delete SymTab;
240
241  // Remove the function from the on-the-side GC table.
242  clearGC();
243
244  // Remove the intrinsicID from the Cache.
245  if (getValueName() && isIntrinsic())
246    getContext().pImpl->IntrinsicIDCache.erase(this);
247}
248
249void Function::BuildLazyArguments() const {
250  // Create the arguments vector, all arguments start out unnamed.
251  FunctionType *FT = getFunctionType();
252  for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i) {
253    assert(!FT->getParamType(i)->isVoidTy() &&
254           "Cannot have void typed arguments!");
255    ArgumentList.push_back(new Argument(FT->getParamType(i)));
256  }
257
258  // Clear the lazy arguments bit.
259  unsigned SDC = getSubclassDataFromValue();
260  const_cast<Function*>(this)->setValueSubclassData(SDC &= ~1);
261}
262
263size_t Function::arg_size() const {
264  return getFunctionType()->getNumParams();
265}
266bool Function::arg_empty() const {
267  return getFunctionType()->getNumParams() == 0;
268}
269
270void Function::setParent(Module *parent) {
271  if (getParent())
272    LeakDetector::addGarbageObject(this);
273  Parent = parent;
274  if (getParent())
275    LeakDetector::removeGarbageObject(this);
276}
277
278// dropAllReferences() - This function causes all the subinstructions to "let
279// go" of all references that they are maintaining.  This allows one to
280// 'delete' a whole class at a time, even though there may be circular
281// references... first all references are dropped, and all use counts go to
282// zero.  Then everything is deleted for real.  Note that no operations are
283// valid on an object that has "dropped all references", except operator
284// delete.
285//
286void Function::dropAllReferences() {
287  for (iterator I = begin(), E = end(); I != E; ++I)
288    I->dropAllReferences();
289
290  // Delete all basic blocks. They are now unused, except possibly by
291  // blockaddresses, but BasicBlock's destructor takes care of those.
292  while (!BasicBlocks.empty())
293    BasicBlocks.begin()->eraseFromParent();
294
295  // Prefix data is stored in a side table.
296  setPrefixData(0);
297}
298
299void Function::addAttribute(unsigned i, Attribute::AttrKind attr) {
300  AttributeSet PAL = getAttributes();
301  PAL = PAL.addAttribute(getContext(), i, attr);
302  setAttributes(PAL);
303}
304
305void Function::addAttributes(unsigned i, AttributeSet attrs) {
306  AttributeSet PAL = getAttributes();
307  PAL = PAL.addAttributes(getContext(), i, attrs);
308  setAttributes(PAL);
309}
310
311void Function::removeAttributes(unsigned i, AttributeSet attrs) {
312  AttributeSet PAL = getAttributes();
313  PAL = PAL.removeAttributes(getContext(), i, attrs);
314  setAttributes(PAL);
315}
316
317// Maintain the GC name for each function in an on-the-side table. This saves
318// allocating an additional word in Function for programs which do not use GC
319// (i.e., most programs) at the cost of increased overhead for clients which do
320// use GC.
321static DenseMap<const Function*,PooledStringPtr> *GCNames;
322static StringPool *GCNamePool;
323static ManagedStatic<sys::SmartRWMutex<true> > GCLock;
324
325bool Function::hasGC() const {
326  sys::SmartScopedReader<true> Reader(*GCLock);
327  return GCNames && GCNames->count(this);
328}
329
330const char *Function::getGC() const {
331  assert(hasGC() && "Function has no collector");
332  sys::SmartScopedReader<true> Reader(*GCLock);
333  return *(*GCNames)[this];
334}
335
336void Function::setGC(const char *Str) {
337  sys::SmartScopedWriter<true> Writer(*GCLock);
338  if (!GCNamePool)
339    GCNamePool = new StringPool();
340  if (!GCNames)
341    GCNames = new DenseMap<const Function*,PooledStringPtr>();
342  (*GCNames)[this] = GCNamePool->intern(Str);
343}
344
345void Function::clearGC() {
346  sys::SmartScopedWriter<true> Writer(*GCLock);
347  if (GCNames) {
348    GCNames->erase(this);
349    if (GCNames->empty()) {
350      delete GCNames;
351      GCNames = 0;
352      if (GCNamePool->empty()) {
353        delete GCNamePool;
354        GCNamePool = 0;
355      }
356    }
357  }
358}
359
360/// copyAttributesFrom - copy all additional attributes (those not needed to
361/// create a Function) from the Function Src to this one.
362void Function::copyAttributesFrom(const GlobalValue *Src) {
363  assert(isa<Function>(Src) && "Expected a Function!");
364  GlobalValue::copyAttributesFrom(Src);
365  const Function *SrcF = cast<Function>(Src);
366  setCallingConv(SrcF->getCallingConv());
367  setAttributes(SrcF->getAttributes());
368  if (SrcF->hasGC())
369    setGC(SrcF->getGC());
370  else
371    clearGC();
372  if (SrcF->hasPrefixData())
373    setPrefixData(SrcF->getPrefixData());
374  else
375    setPrefixData(0);
376}
377
378/// getIntrinsicID - This method returns the ID number of the specified
379/// function, or Intrinsic::not_intrinsic if the function is not an
380/// intrinsic, or if the pointer is null.  This value is always defined to be
381/// zero to allow easy checking for whether a function is intrinsic or not.  The
382/// particular intrinsic functions which correspond to this value are defined in
383/// llvm/Intrinsics.h.  Results are cached in the LLVM context, subsequent
384/// requests for the same ID return results much faster from the cache.
385///
386unsigned Function::getIntrinsicID() const {
387  const ValueName *ValName = this->getValueName();
388  if (!ValName || !isIntrinsic())
389    return 0;
390
391  LLVMContextImpl::IntrinsicIDCacheTy &IntrinsicIDCache =
392    getContext().pImpl->IntrinsicIDCache;
393  if (!IntrinsicIDCache.count(this)) {
394    unsigned Id = lookupIntrinsicID();
395    IntrinsicIDCache[this]=Id;
396    return Id;
397  }
398  return IntrinsicIDCache[this];
399}
400
401/// This private method does the actual lookup of an intrinsic ID when the query
402/// could not be answered from the cache.
403unsigned Function::lookupIntrinsicID() const {
404  const ValueName *ValName = this->getValueName();
405  unsigned Len = ValName->getKeyLength();
406  const char *Name = ValName->getKeyData();
407
408#define GET_FUNCTION_RECOGNIZER
409#include "llvm/IR/Intrinsics.gen"
410#undef GET_FUNCTION_RECOGNIZER
411
412  return 0;
413}
414
415std::string Intrinsic::getName(ID id, ArrayRef<Type*> Tys) {
416  assert(id < num_intrinsics && "Invalid intrinsic ID!");
417  static const char * const Table[] = {
418    "not_intrinsic",
419#define GET_INTRINSIC_NAME_TABLE
420#include "llvm/IR/Intrinsics.gen"
421#undef GET_INTRINSIC_NAME_TABLE
422  };
423  if (Tys.empty())
424    return Table[id];
425  std::string Result(Table[id]);
426  for (unsigned i = 0; i < Tys.size(); ++i) {
427    if (PointerType* PTyp = dyn_cast<PointerType>(Tys[i])) {
428      Result += ".p" + llvm::utostr(PTyp->getAddressSpace()) +
429                EVT::getEVT(PTyp->getElementType()).getEVTString();
430    }
431    else if (Tys[i])
432      Result += "." + EVT::getEVT(Tys[i]).getEVTString();
433  }
434  return Result;
435}
436
437
438/// IIT_Info - These are enumerators that describe the entries returned by the
439/// getIntrinsicInfoTableEntries function.
440///
441/// NOTE: This must be kept in synch with the copy in TblGen/IntrinsicEmitter!
442enum IIT_Info {
443  // Common values should be encoded with 0-15.
444  IIT_Done = 0,
445  IIT_I1   = 1,
446  IIT_I8   = 2,
447  IIT_I16  = 3,
448  IIT_I32  = 4,
449  IIT_I64  = 5,
450  IIT_F16  = 6,
451  IIT_F32  = 7,
452  IIT_F64  = 8,
453  IIT_V2   = 9,
454  IIT_V4   = 10,
455  IIT_V8   = 11,
456  IIT_V16  = 12,
457  IIT_V32  = 13,
458  IIT_PTR  = 14,
459  IIT_ARG  = 15,
460
461  // Values from 16+ are only encodable with the inefficient encoding.
462  IIT_MMX  = 16,
463  IIT_METADATA = 17,
464  IIT_EMPTYSTRUCT = 18,
465  IIT_STRUCT2 = 19,
466  IIT_STRUCT3 = 20,
467  IIT_STRUCT4 = 21,
468  IIT_STRUCT5 = 22,
469  IIT_EXTEND_ARG = 23,
470  IIT_TRUNC_ARG = 24,
471  IIT_ANYPTR = 25,
472  IIT_V1   = 26,
473  IIT_VARARG = 27,
474  IIT_HALF_VEC_ARG = 28
475};
476
477
478static void DecodeIITType(unsigned &NextElt, ArrayRef<unsigned char> Infos,
479                      SmallVectorImpl<Intrinsic::IITDescriptor> &OutputTable) {
480  IIT_Info Info = IIT_Info(Infos[NextElt++]);
481  unsigned StructElts = 2;
482  using namespace Intrinsic;
483
484  switch (Info) {
485  case IIT_Done:
486    OutputTable.push_back(IITDescriptor::get(IITDescriptor::Void, 0));
487    return;
488  case IIT_VARARG:
489    OutputTable.push_back(IITDescriptor::get(IITDescriptor::VarArg, 0));
490    return;
491  case IIT_MMX:
492    OutputTable.push_back(IITDescriptor::get(IITDescriptor::MMX, 0));
493    return;
494  case IIT_METADATA:
495    OutputTable.push_back(IITDescriptor::get(IITDescriptor::Metadata, 0));
496    return;
497  case IIT_F16:
498    OutputTable.push_back(IITDescriptor::get(IITDescriptor::Half, 0));
499    return;
500  case IIT_F32:
501    OutputTable.push_back(IITDescriptor::get(IITDescriptor::Float, 0));
502    return;
503  case IIT_F64:
504    OutputTable.push_back(IITDescriptor::get(IITDescriptor::Double, 0));
505    return;
506  case IIT_I1:
507    OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer, 1));
508    return;
509  case IIT_I8:
510    OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer, 8));
511    return;
512  case IIT_I16:
513    OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer,16));
514    return;
515  case IIT_I32:
516    OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer, 32));
517    return;
518  case IIT_I64:
519    OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer, 64));
520    return;
521  case IIT_V1:
522    OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 1));
523    DecodeIITType(NextElt, Infos, OutputTable);
524    return;
525  case IIT_V2:
526    OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 2));
527    DecodeIITType(NextElt, Infos, OutputTable);
528    return;
529  case IIT_V4:
530    OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 4));
531    DecodeIITType(NextElt, Infos, OutputTable);
532    return;
533  case IIT_V8:
534    OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 8));
535    DecodeIITType(NextElt, Infos, OutputTable);
536    return;
537  case IIT_V16:
538    OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 16));
539    DecodeIITType(NextElt, Infos, OutputTable);
540    return;
541  case IIT_V32:
542    OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 32));
543    DecodeIITType(NextElt, Infos, OutputTable);
544    return;
545  case IIT_PTR:
546    OutputTable.push_back(IITDescriptor::get(IITDescriptor::Pointer, 0));
547    DecodeIITType(NextElt, Infos, OutputTable);
548    return;
549  case IIT_ANYPTR: {  // [ANYPTR addrspace, subtype]
550    OutputTable.push_back(IITDescriptor::get(IITDescriptor::Pointer,
551                                             Infos[NextElt++]));
552    DecodeIITType(NextElt, Infos, OutputTable);
553    return;
554  }
555  case IIT_ARG: {
556    unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
557    OutputTable.push_back(IITDescriptor::get(IITDescriptor::Argument, ArgInfo));
558    return;
559  }
560  case IIT_EXTEND_ARG: {
561    unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
562    OutputTable.push_back(IITDescriptor::get(IITDescriptor::ExtendArgument,
563                                             ArgInfo));
564    return;
565  }
566  case IIT_TRUNC_ARG: {
567    unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
568    OutputTable.push_back(IITDescriptor::get(IITDescriptor::TruncArgument,
569                                             ArgInfo));
570    return;
571  }
572  case IIT_HALF_VEC_ARG: {
573    unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
574    OutputTable.push_back(IITDescriptor::get(IITDescriptor::HalfVecArgument,
575                                             ArgInfo));
576    return;
577  }
578  case IIT_EMPTYSTRUCT:
579    OutputTable.push_back(IITDescriptor::get(IITDescriptor::Struct, 0));
580    return;
581  case IIT_STRUCT5: ++StructElts; // FALL THROUGH.
582  case IIT_STRUCT4: ++StructElts; // FALL THROUGH.
583  case IIT_STRUCT3: ++StructElts; // FALL THROUGH.
584  case IIT_STRUCT2: {
585    OutputTable.push_back(IITDescriptor::get(IITDescriptor::Struct,StructElts));
586
587    for (unsigned i = 0; i != StructElts; ++i)
588      DecodeIITType(NextElt, Infos, OutputTable);
589    return;
590  }
591  }
592  llvm_unreachable("unhandled");
593}
594
595
596#define GET_INTRINSIC_GENERATOR_GLOBAL
597#include "llvm/IR/Intrinsics.gen"
598#undef GET_INTRINSIC_GENERATOR_GLOBAL
599
600void Intrinsic::getIntrinsicInfoTableEntries(ID id,
601                                             SmallVectorImpl<IITDescriptor> &T){
602  // Check to see if the intrinsic's type was expressible by the table.
603  unsigned TableVal = IIT_Table[id-1];
604
605  // Decode the TableVal into an array of IITValues.
606  SmallVector<unsigned char, 8> IITValues;
607  ArrayRef<unsigned char> IITEntries;
608  unsigned NextElt = 0;
609  if ((TableVal >> 31) != 0) {
610    // This is an offset into the IIT_LongEncodingTable.
611    IITEntries = IIT_LongEncodingTable;
612
613    // Strip sentinel bit.
614    NextElt = (TableVal << 1) >> 1;
615  } else {
616    // Decode the TableVal into an array of IITValues.  If the entry was encoded
617    // into a single word in the table itself, decode it now.
618    do {
619      IITValues.push_back(TableVal & 0xF);
620      TableVal >>= 4;
621    } while (TableVal);
622
623    IITEntries = IITValues;
624    NextElt = 0;
625  }
626
627  // Okay, decode the table into the output vector of IITDescriptors.
628  DecodeIITType(NextElt, IITEntries, T);
629  while (NextElt != IITEntries.size() && IITEntries[NextElt] != 0)
630    DecodeIITType(NextElt, IITEntries, T);
631}
632
633
634static Type *DecodeFixedType(ArrayRef<Intrinsic::IITDescriptor> &Infos,
635                             ArrayRef<Type*> Tys, LLVMContext &Context) {
636  using namespace Intrinsic;
637  IITDescriptor D = Infos.front();
638  Infos = Infos.slice(1);
639
640  switch (D.Kind) {
641  case IITDescriptor::Void: return Type::getVoidTy(Context);
642  case IITDescriptor::VarArg: return Type::getVoidTy(Context);
643  case IITDescriptor::MMX: return Type::getX86_MMXTy(Context);
644  case IITDescriptor::Metadata: return Type::getMetadataTy(Context);
645  case IITDescriptor::Half: return Type::getHalfTy(Context);
646  case IITDescriptor::Float: return Type::getFloatTy(Context);
647  case IITDescriptor::Double: return Type::getDoubleTy(Context);
648
649  case IITDescriptor::Integer:
650    return IntegerType::get(Context, D.Integer_Width);
651  case IITDescriptor::Vector:
652    return VectorType::get(DecodeFixedType(Infos, Tys, Context),D.Vector_Width);
653  case IITDescriptor::Pointer:
654    return PointerType::get(DecodeFixedType(Infos, Tys, Context),
655                            D.Pointer_AddressSpace);
656  case IITDescriptor::Struct: {
657    Type *Elts[5];
658    assert(D.Struct_NumElements <= 5 && "Can't handle this yet");
659    for (unsigned i = 0, e = D.Struct_NumElements; i != e; ++i)
660      Elts[i] = DecodeFixedType(Infos, Tys, Context);
661    return StructType::get(Context, ArrayRef<Type*>(Elts,D.Struct_NumElements));
662  }
663
664  case IITDescriptor::Argument:
665    return Tys[D.getArgumentNumber()];
666  case IITDescriptor::ExtendArgument: {
667    Type *Ty = Tys[D.getArgumentNumber()];
668    if (VectorType *VTy = dyn_cast<VectorType>(Ty))
669      return VectorType::getExtendedElementVectorType(VTy);
670
671    return IntegerType::get(Context, 2 * cast<IntegerType>(Ty)->getBitWidth());
672  }
673  case IITDescriptor::TruncArgument: {
674    Type *Ty = Tys[D.getArgumentNumber()];
675    if (VectorType *VTy = dyn_cast<VectorType>(Ty))
676      return VectorType::getTruncatedElementVectorType(VTy);
677
678    IntegerType *ITy = cast<IntegerType>(Ty);
679    assert(ITy->getBitWidth() % 2 == 0);
680    return IntegerType::get(Context, ITy->getBitWidth() / 2);
681  }
682  case IITDescriptor::HalfVecArgument:
683    return VectorType::getHalfElementsVectorType(cast<VectorType>(
684                                                  Tys[D.getArgumentNumber()]));
685  }
686  llvm_unreachable("unhandled");
687}
688
689
690
691FunctionType *Intrinsic::getType(LLVMContext &Context,
692                                 ID id, ArrayRef<Type*> Tys) {
693  SmallVector<IITDescriptor, 8> Table;
694  getIntrinsicInfoTableEntries(id, Table);
695
696  ArrayRef<IITDescriptor> TableRef = Table;
697  Type *ResultTy = DecodeFixedType(TableRef, Tys, Context);
698
699  SmallVector<Type*, 8> ArgTys;
700  while (!TableRef.empty())
701    ArgTys.push_back(DecodeFixedType(TableRef, Tys, Context));
702
703  return FunctionType::get(ResultTy, ArgTys, false);
704}
705
706bool Intrinsic::isOverloaded(ID id) {
707#define GET_INTRINSIC_OVERLOAD_TABLE
708#include "llvm/IR/Intrinsics.gen"
709#undef GET_INTRINSIC_OVERLOAD_TABLE
710}
711
712/// This defines the "Intrinsic::getAttributes(ID id)" method.
713#define GET_INTRINSIC_ATTRIBUTES
714#include "llvm/IR/Intrinsics.gen"
715#undef GET_INTRINSIC_ATTRIBUTES
716
717Function *Intrinsic::getDeclaration(Module *M, ID id, ArrayRef<Type*> Tys) {
718  // There can never be multiple globals with the same name of different types,
719  // because intrinsics must be a specific type.
720  return
721    cast<Function>(M->getOrInsertFunction(getName(id, Tys),
722                                          getType(M->getContext(), id, Tys)));
723}
724
725// This defines the "Intrinsic::getIntrinsicForGCCBuiltin()" method.
726#define GET_LLVM_INTRINSIC_FOR_GCC_BUILTIN
727#include "llvm/IR/Intrinsics.gen"
728#undef GET_LLVM_INTRINSIC_FOR_GCC_BUILTIN
729
730/// hasAddressTaken - returns true if there are any uses of this function
731/// other than direct calls or invokes to it.
732bool Function::hasAddressTaken(const User* *PutOffender) const {
733  for (const Use &U : uses()) {
734    const User *FU = U.getUser();
735    if (isa<BlockAddress>(FU))
736      continue;
737    if (!isa<CallInst>(FU) && !isa<InvokeInst>(FU))
738      return PutOffender ? (*PutOffender = FU, true) : true;
739    ImmutableCallSite CS(cast<Instruction>(FU));
740    if (!CS.isCallee(&U))
741      return PutOffender ? (*PutOffender = FU, true) : true;
742  }
743  return false;
744}
745
746bool Function::isDefTriviallyDead() const {
747  // Check the linkage
748  if (!hasLinkOnceLinkage() && !hasLocalLinkage() &&
749      !hasAvailableExternallyLinkage())
750    return false;
751
752  // Check if the function is used by anything other than a blockaddress.
753  for (const User *U : users())
754    if (!isa<BlockAddress>(U))
755      return false;
756
757  return true;
758}
759
760/// callsFunctionThatReturnsTwice - Return true if the function has a call to
761/// setjmp or other function that gcc recognizes as "returning twice".
762bool Function::callsFunctionThatReturnsTwice() const {
763  for (const_inst_iterator
764         I = inst_begin(this), E = inst_end(this); I != E; ++I) {
765    ImmutableCallSite CS(&*I);
766    if (CS && CS.hasFnAttr(Attribute::ReturnsTwice))
767      return true;
768  }
769
770  return false;
771}
772
773Constant *Function::getPrefixData() const {
774  assert(hasPrefixData());
775  const LLVMContextImpl::PrefixDataMapTy &PDMap =
776      getContext().pImpl->PrefixDataMap;
777  assert(PDMap.find(this) != PDMap.end());
778  return cast<Constant>(PDMap.find(this)->second->getReturnValue());
779}
780
781void Function::setPrefixData(Constant *PrefixData) {
782  if (!PrefixData && !hasPrefixData())
783    return;
784
785  unsigned SCData = getSubclassDataFromValue();
786  LLVMContextImpl::PrefixDataMapTy &PDMap = getContext().pImpl->PrefixDataMap;
787  ReturnInst *&PDHolder = PDMap[this];
788  if (PrefixData) {
789    if (PDHolder)
790      PDHolder->setOperand(0, PrefixData);
791    else
792      PDHolder = ReturnInst::Create(getContext(), PrefixData);
793    SCData |= 2;
794  } else {
795    delete PDHolder;
796    PDMap.erase(this);
797    SCData &= ~2;
798  }
799  setValueSubclassData(SCData);
800}
801