| 1 | //===--- Block.cpp - Allocated blocks for the interpreter -------*- C++ -*-===// |
|---|---|
| 2 | // |
| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| 4 | // See https://llvm.org/LICENSE.txt for license information. |
| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| 6 | // |
| 7 | //===----------------------------------------------------------------------===// |
| 8 | // |
| 9 | // Defines the classes describing allocated blocks. |
| 10 | // |
| 11 | //===----------------------------------------------------------------------===// |
| 12 | |
| 13 | #include "InterpBlock.h" |
| 14 | #include "Pointer.h" |
| 15 | |
| 16 | using namespace clang; |
| 17 | using namespace clang::interp; |
| 18 | |
| 19 | void Block::addPointer(Pointer *P) { |
| 20 | assert(P); |
| 21 | if (IsStatic) { |
| 22 | assert(!Pointers); |
| 23 | return; |
| 24 | } |
| 25 | |
| 26 | #ifndef NDEBUG |
| 27 | assert(!hasPointer(P)); |
| 28 | #endif |
| 29 | if (Pointers) |
| 30 | Pointers->Prev = P; |
| 31 | P->Next = Pointers; |
| 32 | P->Prev = nullptr; |
| 33 | Pointers = P; |
| 34 | } |
| 35 | |
| 36 | void Block::removePointer(Pointer *P) { |
| 37 | assert(P); |
| 38 | if (IsStatic) { |
| 39 | assert(!Pointers); |
| 40 | return; |
| 41 | } |
| 42 | |
| 43 | #ifndef NDEBUG |
| 44 | assert(hasPointer(P)); |
| 45 | #endif |
| 46 | |
| 47 | if (Pointers == P) |
| 48 | Pointers = P->Next; |
| 49 | |
| 50 | if (P->Prev) |
| 51 | P->Prev->Next = P->Next; |
| 52 | if (P->Next) |
| 53 | P->Next->Prev = P->Prev; |
| 54 | } |
| 55 | |
| 56 | void Block::cleanup() { |
| 57 | if (Pointers == nullptr && IsDead) |
| 58 | (reinterpret_cast<DeadBlock *>(this + 1) - 1)->free(); |
| 59 | } |
| 60 | |
| 61 | void Block::replacePointer(Pointer *Old, Pointer *New) { |
| 62 | assert(Old); |
| 63 | assert(New); |
| 64 | if (IsStatic) { |
| 65 | assert(!Pointers); |
| 66 | return; |
| 67 | } |
| 68 | |
| 69 | #ifndef NDEBUG |
| 70 | assert(hasPointer(Old)); |
| 71 | #endif |
| 72 | |
| 73 | removePointer(P: Old); |
| 74 | addPointer(P: New); |
| 75 | |
| 76 | Old->PointeeStorage.BS.Pointee = nullptr; |
| 77 | |
| 78 | #ifndef NDEBUG |
| 79 | assert(!hasPointer(Old)); |
| 80 | assert(hasPointer(New)); |
| 81 | #endif |
| 82 | } |
| 83 | |
| 84 | #ifndef NDEBUG |
| 85 | bool Block::hasPointer(const Pointer *P) const { |
| 86 | for (const Pointer *C = Pointers; C; C = C->Next) { |
| 87 | if (C == P) |
| 88 | return true; |
| 89 | } |
| 90 | return false; |
| 91 | } |
| 92 | #endif |
| 93 | |
| 94 | DeadBlock::DeadBlock(DeadBlock *&Root, Block *Blk) |
| 95 | : Root(Root), B(Blk->Desc, Blk->IsStatic, Blk->IsExtern, /*isDead=*/true) { |
| 96 | // Add the block to the chain of dead blocks. |
| 97 | if (Root) |
| 98 | Root->Prev = this; |
| 99 | |
| 100 | Next = Root; |
| 101 | Prev = nullptr; |
| 102 | Root = this; |
| 103 | |
| 104 | // Transfer pointers. |
| 105 | B.Pointers = Blk->Pointers; |
| 106 | for (Pointer *P = Blk->Pointers; P; P = P->Next) |
| 107 | P->PointeeStorage.BS.Pointee = &B; |
| 108 | } |
| 109 | |
| 110 | void DeadBlock::free() { |
| 111 | if (Prev) |
| 112 | Prev->Next = Next; |
| 113 | if (Next) |
| 114 | Next->Prev = Prev; |
| 115 | if (Root == this) |
| 116 | Root = Next; |
| 117 | std::free(ptr: this); |
| 118 | } |
| 119 |