Attributes.cpp revision 6f78fbbc630d2b86fb752574f5ad74473f57dfb1 
1//===-- Attribute.cpp - Implement AttributesList -------------------------===//
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 Attribute, AttributeImpl, AttrBuilder,
11// AttributeSetImpl, and AttributeSet classes.
12//
13//===----------------------------------------------------------------------===//
14
15#include "llvm/IR/Attributes.h"
16#include "AttributeImpl.h"
17#include "LLVMContextImpl.h"
18#include "llvm/ADT/FoldingSet.h"
19#include "llvm/ADT/StringExtras.h"
20#include "llvm/IR/Type.h"
21#include "llvm/Support/Atomic.h"
22#include "llvm/Support/Debug.h"
23#include "llvm/Support/ManagedStatic.h"
24#include "llvm/Support/Mutex.h"
25#include "llvm/Support/raw_ostream.h"
26using namespace llvm;
27
28//===----------------------------------------------------------------------===//
29// Attribute Implementation
30//===----------------------------------------------------------------------===//
31
32Attribute Attribute::get(LLVMContext &Context, ArrayRef<AttrKind> Vals) {
33  AttrBuilder B;
34  for (ArrayRef<AttrKind>::iterator I = Vals.begin(), E = Vals.end();
35       I != E; ++I)
36    B.addAttribute(*I);
37  return Attribute::get(Context, B);
38}
39
40Attribute Attribute::get(LLVMContext &Context, AttrBuilder &B) {
41  // If there are no attributes, return an empty Attribute class.
42  if (!B.hasAttributes())
43    return Attribute();
44
45  // Otherwise, build a key to look up the existing attributes.
46  LLVMContextImpl *pImpl = Context.pImpl;
47  FoldingSetNodeID ID;
48  ID.AddInteger(B.getBitMask());
49
50  void *InsertPoint;
51  AttributeImpl *PA = pImpl->AttrsSet.FindNodeOrInsertPos(ID, InsertPoint);
52
53  if (!PA) {
54    // If we didn't find any existing attributes of the same shape then create a
55    // new one and insert it.
56    PA = new AttributeImpl(Context, B.getBitMask());
57    pImpl->AttrsSet.InsertNode(PA, InsertPoint);
58  }
59
60  // Return the AttributesList that we found or created.
61  return Attribute(PA);
62}
63
64bool Attribute::hasAttribute(AttrKind Val) const {
65  return pImpl && pImpl->hasAttribute(Val);
66}
67
68bool Attribute::hasAttributes() const {
69  return pImpl && pImpl->hasAttributes();
70}
71
72/// This returns the alignment field of an attribute as a byte alignment value.
73unsigned Attribute::getAlignment() const {
74  if (!hasAttribute(Attribute::Alignment))
75    return 0;
76  return 1U << ((pImpl->getAlignment() >> 16) - 1);
77}
78
79void Attribute::setAlignment(unsigned Align) {
80  assert(hasAttribute(Attribute::Alignment) &&
81         "Trying to set the alignment on a non-alignment attribute!");
82  pImpl->setAlignment(Align);
83}
84
85/// This returns the stack alignment field of an attribute as a byte alignment
86/// value.
87unsigned Attribute::getStackAlignment() const {
88  if (!hasAttribute(Attribute::StackAlignment))
89    return 0;
90  return 1U << ((pImpl->getStackAlignment() >> 26) - 1);
91}
92
93void Attribute::setStackAlignment(unsigned Align) {
94  assert(hasAttribute(Attribute::StackAlignment) &&
95         "Trying to set the stack alignment on a non-alignment attribute!");
96  pImpl->setStackAlignment(Align);
97}
98
99bool Attribute::operator==(AttrKind K) const {
100  return pImpl && *pImpl == K;
101}
102bool Attribute::operator!=(AttrKind K) const {
103  return !(*this == K);
104}
105
106uint64_t Attribute::getBitMask() const {
107  return pImpl ? pImpl->getBitMask() : 0;
108}
109
110Attribute Attribute::typeIncompatible(Type *Ty) {
111  AttrBuilder Incompatible;
112
113  if (!Ty->isIntegerTy())
114    // Attribute that only apply to integers.
115    Incompatible.addAttribute(Attribute::SExt)
116      .addAttribute(Attribute::ZExt);
117
118  if (!Ty->isPointerTy())
119    // Attribute that only apply to pointers.
120    Incompatible.addAttribute(Attribute::ByVal)
121      .addAttribute(Attribute::Nest)
122      .addAttribute(Attribute::NoAlias)
123      .addAttribute(Attribute::NoCapture)
124      .addAttribute(Attribute::StructRet);
125
126  return Attribute::get(Ty->getContext(), Incompatible);
127}
128
129/// encodeLLVMAttributesForBitcode - This returns an integer containing an
130/// encoding of all the LLVM attributes found in the given attribute bitset.
131/// Any change to this encoding is a breaking change to bitcode compatibility.
132uint64_t Attribute::encodeLLVMAttributesForBitcode(Attribute Attrs) {
133  // FIXME: It doesn't make sense to store the alignment information as an
134  // expanded out value, we should store it as a log2 value.  However, we can't
135  // just change that here without breaking bitcode compatibility.  If this ever
136  // becomes a problem in practice, we should introduce new tag numbers in the
137  // bitcode file and have those tags use a more efficiently encoded alignment
138  // field.
139
140  // Store the alignment in the bitcode as a 16-bit raw value instead of a 5-bit
141  // log2 encoded value. Shift the bits above the alignment up by 11 bits.
142  uint64_t EncodedAttrs = Attrs.getBitMask() & 0xffff;
143  if (Attrs.hasAttribute(Attribute::Alignment))
144    EncodedAttrs |= Attrs.getAlignment() << 16;
145  EncodedAttrs |= (Attrs.getBitMask() & (0xffffULL << 21)) << 11;
146  return EncodedAttrs;
147}
148
149/// decodeLLVMAttributesForBitcode - This returns an attribute bitset containing
150/// the LLVM attributes that have been decoded from the given integer.  This
151/// function must stay in sync with 'encodeLLVMAttributesForBitcode'.
152Attribute Attribute::decodeLLVMAttributesForBitcode(LLVMContext &C,
153                                                      uint64_t EncodedAttrs) {
154  // The alignment is stored as a 16-bit raw value from bits 31--16.  We shift
155  // the bits above 31 down by 11 bits.
156  unsigned Alignment = (EncodedAttrs & (0xffffULL << 16)) >> 16;
157  assert((!Alignment || isPowerOf2_32(Alignment)) &&
158         "Alignment must be a power of two.");
159
160  AttrBuilder B(EncodedAttrs & 0xffff);
161  if (Alignment)
162    B.addAlignmentAttr(Alignment);
163  B.addRawValue((EncodedAttrs & (0xffffULL << 32)) >> 11);
164  return Attribute::get(C, B);
165}
166
167std::string Attribute::getAsString() const {
168  std::string Result;
169  if (hasAttribute(Attribute::ZExt))
170    Result += "zeroext ";
171  if (hasAttribute(Attribute::SExt))
172    Result += "signext ";
173  if (hasAttribute(Attribute::NoReturn))
174    Result += "noreturn ";
175  if (hasAttribute(Attribute::NoUnwind))
176    Result += "nounwind ";
177  if (hasAttribute(Attribute::UWTable))
178    Result += "uwtable ";
179  if (hasAttribute(Attribute::ReturnsTwice))
180    Result += "returns_twice ";
181  if (hasAttribute(Attribute::InReg))
182    Result += "inreg ";
183  if (hasAttribute(Attribute::NoAlias))
184    Result += "noalias ";
185  if (hasAttribute(Attribute::NoCapture))
186    Result += "nocapture ";
187  if (hasAttribute(Attribute::StructRet))
188    Result += "sret ";
189  if (hasAttribute(Attribute::ByVal))
190    Result += "byval ";
191  if (hasAttribute(Attribute::Nest))
192    Result += "nest ";
193  if (hasAttribute(Attribute::ReadNone))
194    Result += "readnone ";
195  if (hasAttribute(Attribute::ReadOnly))
196    Result += "readonly ";
197  if (hasAttribute(Attribute::OptimizeForSize))
198    Result += "optsize ";
199  if (hasAttribute(Attribute::NoInline))
200    Result += "noinline ";
201  if (hasAttribute(Attribute::InlineHint))
202    Result += "inlinehint ";
203  if (hasAttribute(Attribute::AlwaysInline))
204    Result += "alwaysinline ";
205  if (hasAttribute(Attribute::StackProtect))
206    Result += "ssp ";
207  if (hasAttribute(Attribute::StackProtectReq))
208    Result += "sspreq ";
209  if (hasAttribute(Attribute::NoRedZone))
210    Result += "noredzone ";
211  if (hasAttribute(Attribute::NoImplicitFloat))
212    Result += "noimplicitfloat ";
213  if (hasAttribute(Attribute::Naked))
214    Result += "naked ";
215  if (hasAttribute(Attribute::NonLazyBind))
216    Result += "nonlazybind ";
217  if (hasAttribute(Attribute::AddressSafety))
218    Result += "address_safety ";
219  if (hasAttribute(Attribute::MinSize))
220    Result += "minsize ";
221  if (hasAttribute(Attribute::StackAlignment)) {
222    Result += "alignstack(";
223    Result += utostr(getStackAlignment());
224    Result += ") ";
225  }
226  if (hasAttribute(Attribute::Alignment)) {
227    Result += "align ";
228    Result += utostr(getAlignment());
229    Result += " ";
230  }
231  if (hasAttribute(Attribute::NoDuplicate))
232    Result += "noduplicate ";
233  // Trim the trailing space.
234  assert(!Result.empty() && "Unknown attribute!");
235  Result.erase(Result.end()-1);
236  return Result;
237}
238
239//===----------------------------------------------------------------------===//
240// AttrBuilder Method Implementations
241//===----------------------------------------------------------------------===//
242
243void AttrBuilder::clear() {
244  Attrs.clear();
245  Alignment = StackAlignment = 0;
246}
247
248AttrBuilder &AttrBuilder::addAttribute(Attribute::AttrKind Val) {
249  Attrs.insert(Val);
250  return *this;
251}
252
253AttrBuilder &AttrBuilder::removeAttribute(Attribute::AttrKind Val) {
254  Attrs.erase(Val);
255  if (Val == Attribute::Alignment)
256    Alignment = 0;
257  else if (Val == Attribute::StackAlignment)
258    StackAlignment = 0;
259
260  return *this;
261}
262
263AttrBuilder &AttrBuilder::addAlignmentAttr(unsigned Align) {
264  if (Align == 0) return *this;
265
266  assert(isPowerOf2_32(Align) && "Alignment must be a power of two.");
267  assert(Align <= 0x40000000 && "Alignment too large.");
268
269  Attrs.insert(Attribute::Alignment);
270  Alignment = Align;
271  return *this;
272}
273
274AttrBuilder &AttrBuilder::addStackAlignmentAttr(unsigned Align) {
275  // Default alignment, allow the target to define how to align it.
276  if (Align == 0) return *this;
277
278  assert(isPowerOf2_32(Align) && "Alignment must be a power of two.");
279  assert(Align <= 0x100 && "Alignment too large.");
280
281  Attrs.insert(Attribute::StackAlignment);
282  StackAlignment = Align;
283  return *this;
284}
285
286AttrBuilder &AttrBuilder::addRawValue(uint64_t Val) {
287  for (Attribute::AttrKind I = Attribute::None; I != Attribute::EndAttrKinds;
288       I = Attribute::AttrKind(I + 1)) {
289    if (uint64_t A = (Val & AttributeImpl::getAttrMask(I))) {
290      Attrs.insert(I);
291
292      if (I == Attribute::Alignment)
293        Alignment = 1ULL << ((A >> 16) - 1);
294      else if (I == Attribute::StackAlignment)
295        StackAlignment = 1ULL << ((A >> 26)-1);
296    }
297  }
298
299  return *this;
300}
301
302AttrBuilder &AttrBuilder::addAttributes(const Attribute &A) {
303  uint64_t Mask = A.getBitMask();
304
305  for (Attribute::AttrKind I = Attribute::None; I != Attribute::EndAttrKinds;
306       I = Attribute::AttrKind(I + 1)) {
307    if (uint64_t A = (Mask & AttributeImpl::getAttrMask(I))) {
308      Attrs.insert(I);
309
310      if (I == Attribute::Alignment)
311        Alignment = 1ULL << ((A >> 16) - 1);
312      else if (I == Attribute::StackAlignment)
313        StackAlignment = 1ULL << ((A >> 26)-1);
314    }
315  }
316
317  return *this;
318}
319
320AttrBuilder &AttrBuilder::removeAttributes(const Attribute &A){
321  uint64_t Mask = A.getBitMask();
322
323  for (Attribute::AttrKind I = Attribute::None; I != Attribute::EndAttrKinds;
324       I = Attribute::AttrKind(I + 1)) {
325    if (Mask & AttributeImpl::getAttrMask(I)) {
326      Attrs.erase(I);
327
328      if (I == Attribute::Alignment)
329        Alignment = 0;
330      else if (I == Attribute::StackAlignment)
331        StackAlignment = 0;
332    }
333  }
334
335  return *this;
336}
337
338bool AttrBuilder::contains(Attribute::AttrKind A) const {
339  return Attrs.count(A);
340}
341
342bool AttrBuilder::hasAttributes() const {
343  return !Attrs.empty();
344}
345
346bool AttrBuilder::hasAttributes(const Attribute &A) const {
347  return getBitMask() & A.getBitMask();
348}
349
350bool AttrBuilder::hasAlignmentAttr() const {
351  return Alignment != 0;
352}
353
354uint64_t AttrBuilder::getBitMask() const {
355  uint64_t Mask = 0;
356
357  for (DenseSet<Attribute::AttrKind>::const_iterator I = Attrs.begin(),
358         E = Attrs.end(); I != E; ++I) {
359    Attribute::AttrKind Kind = *I;
360
361    if (Kind == Attribute::Alignment)
362      Mask |= (Log2_32(Alignment) + 1) << 16;
363    else if (Kind == Attribute::StackAlignment)
364      Mask |= (Log2_32(StackAlignment) + 1) << 26;
365    else
366      Mask |= AttributeImpl::getAttrMask(Kind);
367  }
368
369  return Mask;
370}
371
372bool AttrBuilder::operator==(const AttrBuilder &B) {
373  SmallVector<Attribute::AttrKind, 8> This(Attrs.begin(), Attrs.end());
374  SmallVector<Attribute::AttrKind, 8> That(B.Attrs.begin(), B.Attrs.end());
375  return This == That;
376}
377
378//===----------------------------------------------------------------------===//
379// AttributeImpl Definition
380//===----------------------------------------------------------------------===//
381
382AttributeImpl::AttributeImpl(LLVMContext &C, uint64_t data)
383  : Context(C) {
384  Data = ConstantInt::get(Type::getInt64Ty(C), data);
385}
386AttributeImpl::AttributeImpl(LLVMContext &C, Attribute::AttrKind data)
387  : Context(C) {
388  Data = ConstantInt::get(Type::getInt64Ty(C), data);
389}
390AttributeImpl::AttributeImpl(LLVMContext &C, Attribute::AttrKind data,
391                             ArrayRef<Constant*> values)
392  : Context(C) {
393  Data = ConstantInt::get(Type::getInt64Ty(C), data);
394  Vals.reserve(values.size());
395  Vals.append(values.begin(), values.end());
396}
397AttributeImpl::AttributeImpl(LLVMContext &C, StringRef data)
398  : Context(C) {
399  Data = ConstantDataArray::getString(C, data);
400}
401
402bool AttributeImpl::operator==(Attribute::AttrKind Kind) const {
403  if (ConstantInt *CI = dyn_cast<ConstantInt>(Data))
404    return CI->getZExtValue() == Kind;
405  return false;
406}
407bool AttributeImpl::operator!=(Attribute::AttrKind Kind) const {
408  return !(*this == Kind);
409}
410
411bool AttributeImpl::operator==(StringRef Kind) const {
412  if (ConstantDataArray *CDA = dyn_cast<ConstantDataArray>(Data))
413    if (CDA->isString())
414      return CDA->getAsString() == Kind;
415  return false;
416}
417bool AttributeImpl::operator!=(StringRef Kind) const {
418  return !(*this == Kind);
419}
420
421uint64_t AttributeImpl::getBitMask() const {
422  // FIXME: Remove this.
423  return cast<ConstantInt>(Data)->getZExtValue();
424}
425
426uint64_t AttributeImpl::getAttrMask(Attribute::AttrKind Val) {
427  switch (Val) {
428  case Attribute::EndAttrKinds:
429  case Attribute::AttrKindEmptyKey:
430  case Attribute::AttrKindTombstoneKey:
431    llvm_unreachable("Synthetic enumerators which should never get here");
432
433  case Attribute::None:            return 0;
434  case Attribute::ZExt:            return 1 << 0;
435  case Attribute::SExt:            return 1 << 1;
436  case Attribute::NoReturn:        return 1 << 2;
437  case Attribute::InReg:           return 1 << 3;
438  case Attribute::StructRet:       return 1 << 4;
439  case Attribute::NoUnwind:        return 1 << 5;
440  case Attribute::NoAlias:         return 1 << 6;
441  case Attribute::ByVal:           return 1 << 7;
442  case Attribute::Nest:            return 1 << 8;
443  case Attribute::ReadNone:        return 1 << 9;
444  case Attribute::ReadOnly:        return 1 << 10;
445  case Attribute::NoInline:        return 1 << 11;
446  case Attribute::AlwaysInline:    return 1 << 12;
447  case Attribute::OptimizeForSize: return 1 << 13;
448  case Attribute::StackProtect:    return 1 << 14;
449  case Attribute::StackProtectReq: return 1 << 15;
450  case Attribute::Alignment:       return 31 << 16;
451  case Attribute::NoCapture:       return 1 << 21;
452  case Attribute::NoRedZone:       return 1 << 22;
453  case Attribute::NoImplicitFloat: return 1 << 23;
454  case Attribute::Naked:           return 1 << 24;
455  case Attribute::InlineHint:      return 1 << 25;
456  case Attribute::StackAlignment:  return 7 << 26;
457  case Attribute::ReturnsTwice:    return 1 << 29;
458  case Attribute::UWTable:         return 1 << 30;
459  case Attribute::NonLazyBind:     return 1U << 31;
460  case Attribute::AddressSafety:   return 1ULL << 32;
461  case Attribute::MinSize:         return 1ULL << 33;
462  case Attribute::NoDuplicate:     return 1ULL << 34;
463  }
464  llvm_unreachable("Unsupported attribute type");
465}
466
467bool AttributeImpl::hasAttribute(Attribute::AttrKind A) const {
468  return (getBitMask() & getAttrMask(A)) != 0;
469}
470
471bool AttributeImpl::hasAttributes() const {
472  return getBitMask() != 0;
473}
474
475uint64_t AttributeImpl::getAlignment() const {
476  return getBitMask() & getAttrMask(Attribute::Alignment);
477}
478
479void AttributeImpl::setAlignment(unsigned Align) {
480  Vals.push_back(ConstantInt::get(Type::getInt64Ty(Context), Align));
481}
482
483uint64_t AttributeImpl::getStackAlignment() const {
484  return getBitMask() & getAttrMask(Attribute::StackAlignment);
485}
486
487void AttributeImpl::setStackAlignment(unsigned Align) {
488  Vals.push_back(ConstantInt::get(Type::getInt64Ty(Context), Align));
489}
490
491//===----------------------------------------------------------------------===//
492// AttributeSetImpl Definition
493//===----------------------------------------------------------------------===//
494
495AttributeSet AttributeSet::get(LLVMContext &C,
496                               ArrayRef<AttributeWithIndex> Attrs) {
497  // If there are no attributes then return a null AttributesList pointer.
498  if (Attrs.empty())
499    return AttributeSet();
500
501#ifndef NDEBUG
502  for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
503    assert(Attrs[i].Attrs.hasAttributes() &&
504           "Pointless attribute!");
505    assert((!i || Attrs[i-1].Index < Attrs[i].Index) &&
506           "Misordered AttributesList!");
507  }
508#endif
509
510  // Otherwise, build a key to look up the existing attributes.
511  LLVMContextImpl *pImpl = C.pImpl;
512  FoldingSetNodeID ID;
513  AttributeSetImpl::Profile(ID, Attrs);
514
515  void *InsertPoint;
516  AttributeSetImpl *PA = pImpl->AttrsLists.FindNodeOrInsertPos(ID, InsertPoint);
517
518  // If we didn't find any existing attributes of the same shape then
519  // create a new one and insert it.
520  if (!PA) {
521    PA = new AttributeSetImpl(C, Attrs);
522    pImpl->AttrsLists.InsertNode(PA, InsertPoint);
523  }
524
525  // Return the AttributesList that we found or created.
526  return AttributeSet(PA);
527}
528
529AttributeSet AttributeSet::get(LLVMContext &C, unsigned Idx, AttrBuilder &B) {
530  SmallVector<AttributeWithIndex, 8> Attrs;
531  for (AttrBuilder::iterator I = B.begin(), E = B.end(); I != E; ++I) {
532    Attribute::AttrKind Kind = *I;
533    Attribute A = Attribute::get(C, Kind);
534
535    if (Kind == Attribute::Alignment)
536      A.setAlignment(B.getAlignment());
537    else if (Kind == Attribute::StackAlignment)
538      A.setStackAlignment(B.getStackAlignment());
539
540    Attrs.push_back(AttributeWithIndex::get(Idx, A));
541  }
542
543  return get(C, Attrs);
544}
545
546//===----------------------------------------------------------------------===//
547// AttributeSet Method Implementations
548//===----------------------------------------------------------------------===//
549
550const AttributeSet &AttributeSet::operator=(const AttributeSet &RHS) {
551  AttrList = RHS.AttrList;
552  return *this;
553}
554
555/// getNumSlots - Return the number of slots used in this attribute list.
556/// This is the number of arguments that have an attribute set on them
557/// (including the function itself).
558unsigned AttributeSet::getNumSlots() const {
559  return AttrList ? AttrList->getNumAttributes() : 0;
560}
561
562/// getSlot - Return the AttributeWithIndex at the specified slot.  This
563/// holds a number plus a set of attributes.
564const AttributeWithIndex &AttributeSet::getSlot(unsigned Slot) const {
565  assert(AttrList && Slot < AttrList->getNumAttributes() &&
566         "Slot # out of range!");
567  return AttrList->getAttributes()[Slot];
568}
569
570bool AttributeSet::hasAttribute(unsigned Index, Attribute::AttrKind Kind) const{
571  return getAttributes(Index).hasAttribute(Kind);
572}
573
574bool AttributeSet::hasAttributes(unsigned Index) const {
575  return getAttributes(Index).hasAttributes();
576}
577
578std::string AttributeSet::getAsString(unsigned Index) const {
579  return getAttributes(Index).getAsString();
580}
581
582unsigned AttributeSet::getStackAlignment(unsigned Index) const {
583  return getAttributes(Index).getStackAlignment();
584}
585
586uint64_t AttributeSet::getBitMask(unsigned Index) const {
587  // FIXME: Remove this.
588  return getAttributes(Index).getBitMask();
589}
590
591/// getAttributes - The attributes for the specified index are returned.
592/// Attributes for the result are denoted with Idx = 0.  Function attributes are
593/// denoted with Idx = ~0.
594Attribute AttributeSet::getAttributes(unsigned Idx) const {
595  if (AttrList == 0) return Attribute();
596
597  ArrayRef<AttributeWithIndex> Attrs = AttrList->getAttributes();
598  for (unsigned i = 0, e = Attrs.size(); i != e && Attrs[i].Index <= Idx; ++i)
599    if (Attrs[i].Index == Idx)
600      return Attrs[i].Attrs;
601
602  return Attribute();
603}
604
605/// hasAttrSomewhere - Return true if the specified attribute is set for at
606/// least one parameter or for the return value.
607bool AttributeSet::hasAttrSomewhere(Attribute::AttrKind Attr) const {
608  if (AttrList == 0) return false;
609
610  ArrayRef<AttributeWithIndex> Attrs = AttrList->getAttributes();
611  for (unsigned i = 0, e = Attrs.size(); i != e; ++i)
612    if (Attrs[i].Attrs.hasAttribute(Attr))
613      return true;
614
615  return false;
616}
617
618AttributeSet AttributeSet::addAttr(LLVMContext &C, unsigned Idx,
619                                   Attribute Attrs) const {
620  Attribute OldAttrs = getAttributes(Idx);
621#ifndef NDEBUG
622  // FIXME it is not obvious how this should work for alignment.
623  // For now, say we can't change a known alignment.
624  unsigned OldAlign = OldAttrs.getAlignment();
625  unsigned NewAlign = Attrs.getAlignment();
626  assert((!OldAlign || !NewAlign || OldAlign == NewAlign) &&
627         "Attempt to change alignment!");
628#endif
629
630  AttrBuilder NewAttrs =
631    AttrBuilder(OldAttrs).addAttributes(Attrs);
632  if (NewAttrs == AttrBuilder(OldAttrs))
633    return *this;
634
635  SmallVector<AttributeWithIndex, 8> NewAttrList;
636  if (AttrList == 0)
637    NewAttrList.push_back(AttributeWithIndex::get(Idx, Attrs));
638  else {
639    ArrayRef<AttributeWithIndex> OldAttrList = AttrList->getAttributes();
640    unsigned i = 0, e = OldAttrList.size();
641    // Copy attributes for arguments before this one.
642    for (; i != e && OldAttrList[i].Index < Idx; ++i)
643      NewAttrList.push_back(OldAttrList[i]);
644
645    // If there are attributes already at this index, merge them in.
646    if (i != e && OldAttrList[i].Index == Idx) {
647      Attrs =
648        Attribute::get(C, AttrBuilder(Attrs).
649                        addAttributes(OldAttrList[i].Attrs));
650      ++i;
651    }
652
653    NewAttrList.push_back(AttributeWithIndex::get(Idx, Attrs));
654
655    // Copy attributes for arguments after this one.
656    NewAttrList.insert(NewAttrList.end(),
657                       OldAttrList.begin()+i, OldAttrList.end());
658  }
659
660  return get(C, NewAttrList);
661}
662
663AttributeSet AttributeSet::removeAttr(LLVMContext &C, unsigned Idx,
664                                      Attribute Attrs) const {
665#ifndef NDEBUG
666  // FIXME it is not obvious how this should work for alignment.
667  // For now, say we can't pass in alignment, which no current use does.
668  assert(!Attrs.hasAttribute(Attribute::Alignment) &&
669         "Attempt to exclude alignment!");
670#endif
671  if (AttrList == 0) return AttributeSet();
672
673  Attribute OldAttrs = getAttributes(Idx);
674  AttrBuilder NewAttrs =
675    AttrBuilder(OldAttrs).removeAttributes(Attrs);
676  if (NewAttrs == AttrBuilder(OldAttrs))
677    return *this;
678
679  SmallVector<AttributeWithIndex, 8> NewAttrList;
680  ArrayRef<AttributeWithIndex> OldAttrList = AttrList->getAttributes();
681  unsigned i = 0, e = OldAttrList.size();
682
683  // Copy attributes for arguments before this one.
684  for (; i != e && OldAttrList[i].Index < Idx; ++i)
685    NewAttrList.push_back(OldAttrList[i]);
686
687  // If there are attributes already at this index, merge them in.
688  assert(OldAttrList[i].Index == Idx && "Attribute isn't set?");
689  Attrs = Attribute::get(C, AttrBuilder(OldAttrList[i].Attrs).
690                          removeAttributes(Attrs));
691  ++i;
692  if (Attrs.hasAttributes()) // If any attributes left for this param, add them.
693    NewAttrList.push_back(AttributeWithIndex::get(Idx, Attrs));
694
695  // Copy attributes for arguments after this one.
696  NewAttrList.insert(NewAttrList.end(),
697                     OldAttrList.begin()+i, OldAttrList.end());
698
699  return get(C, NewAttrList);
700}
701
702void AttributeSet::dump() const {
703  dbgs() << "PAL[ ";
704  for (unsigned i = 0; i < getNumSlots(); ++i) {
705    const AttributeWithIndex &PAWI = getSlot(i);
706    dbgs() << "{ " << PAWI.Index << ", " << PAWI.Attrs.getAsString() << " } ";
707  }
708
709  dbgs() << "]\n";
710}
711