| //===-- Use.cpp - Implement the Use class ---------------------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements the algorithm for finding the User of a Use. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/User.h" |
| |
| namespace llvm { |
| |
| //===----------------------------------------------------------------------===// |
| // Use swap Implementation |
| //===----------------------------------------------------------------------===// |
| |
| void Use::swap(Use &RHS) { |
| Value *V1(Val); |
| Value *V2(RHS.Val); |
| if (V1 != V2) { |
| if (V1) { |
| removeFromList(); |
| } |
| |
| if (V2) { |
| RHS.removeFromList(); |
| Val = V2; |
| V2->addUse(*this); |
| } else { |
| Val = 0; |
| } |
| |
| if (V1) { |
| RHS.Val = V1; |
| V1->addUse(RHS); |
| } else { |
| RHS.Val = 0; |
| } |
| } |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Use getImpliedUser Implementation |
| //===----------------------------------------------------------------------===// |
| |
| const Use *Use::getImpliedUser() const { |
| const Use *Current = this; |
| |
| while (true) { |
| unsigned Tag = extractTag<PrevPtrTag, fullStopTag>((Current++)->Prev); |
| switch (Tag) { |
| case zeroDigitTag: |
| case oneDigitTag: |
| continue; |
| |
| case stopTag: { |
| ++Current; |
| ptrdiff_t Offset = 1; |
| while (true) { |
| unsigned Tag = extractTag<PrevPtrTag, fullStopTag>(Current->Prev); |
| switch (Tag) { |
| case zeroDigitTag: |
| case oneDigitTag: |
| ++Current; |
| Offset = (Offset << 1) + Tag; |
| continue; |
| default: |
| return Current + Offset; |
| } |
| } |
| } |
| |
| case fullStopTag: |
| return Current; |
| } |
| } |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Use initTags Implementation |
| //===----------------------------------------------------------------------===// |
| |
| Use *Use::initTags(Use * const Start, Use *Stop, ptrdiff_t Done) { |
| ptrdiff_t Count = Done; |
| while (Start != Stop) { |
| --Stop; |
| Stop->Val = 0; |
| if (!Count) { |
| Stop->Prev = reinterpret_cast<Use**>(Done == 0 ? fullStopTag : stopTag); |
| ++Done; |
| Count = Done; |
| } else { |
| Stop->Prev = reinterpret_cast<Use**>(Count & 1); |
| Count >>= 1; |
| ++Done; |
| } |
| } |
| |
| return Start; |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Use zap Implementation |
| //===----------------------------------------------------------------------===// |
| |
| void Use::zap(Use *Start, const Use *Stop, bool del) { |
| if (del) { |
| while (Start != Stop) { |
| (--Stop)->~Use(); |
| } |
| ::operator delete(Start); |
| return; |
| } |
| |
| while (Start != Stop) { |
| (Start++)->set(0); |
| } |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // AugmentedUse layout struct |
| //===----------------------------------------------------------------------===// |
| |
| struct AugmentedUse : Use { |
| User *ref; |
| AugmentedUse(); // not implemented |
| }; |
| |
| |
| //===----------------------------------------------------------------------===// |
| // Use getUser Implementation |
| //===----------------------------------------------------------------------===// |
| |
| User *Use::getUser() const { |
| const Use *End = getImpliedUser(); |
| User *She = static_cast<const AugmentedUse*>(End - 1)->ref; |
| She = extractTag<Tag, tagOne>(She) |
| ? llvm::stripTag<tagOne>(She) |
| : reinterpret_cast<User*>(const_cast<Use*>(End)); |
| |
| return She; |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // User allocHungoffUses Implementation |
| //===----------------------------------------------------------------------===// |
| |
| Use *User::allocHungoffUses(unsigned N) const { |
| Use *Begin = static_cast<Use*>(::operator new(sizeof(Use) * N |
| + sizeof(AugmentedUse) |
| - sizeof(Use))); |
| Use *End = Begin + N; |
| static_cast<AugmentedUse&>(End[-1]).ref = addTag(this, tagOne); |
| return Use::initTags(Begin, End); |
| } |
| |
| } // End llvm namespace |