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 "Block.h"
14#include "Pointer.h"
15
16using namespace clang;
17using namespace clang::interp;
18
19
20
21void Block::addPointer(Pointer *P) {
22  if (IsStatic)
23    return;
24  if (Pointers)
25    Pointers->Prev = P;
26  P->Next = Pointers;
27  P->Prev = nullptr;
28  Pointers = P;
29}
30
31void Block::removePointer(Pointer *P) {
32  if (IsStatic)
33    return;
34  if (Pointers == P)
35    Pointers = P->Next;
36  if (P->Prev)
37    P->Prev->Next = P->Next;
38  if (P->Next)
39    P->Next->Prev = P->Prev;
40}
41
42void Block::cleanup() {
43  if (Pointers == nullptr && IsDead)
44    (reinterpret_cast<DeadBlock *>(this + 1) - 1)->free();
45}
46
47void Block::movePointer(Pointer *From, Pointer *To) {
48  if (IsStatic)
49    return;
50  To->Prev = From->Prev;
51  if (To->Prev)
52    To->Prev->Next = To;
53  To->Next = From->Next;
54  if (To->Next)
55    To->Next->Prev = To;
56  if (Pointers == From)
57    Pointers = To;
58
59  From->Prev = nullptr;
60  From->Next = nullptr;
61}
62
63DeadBlock::DeadBlock(DeadBlock *&Root, Block *Blk)
64    : Root(Root), B(Blk->Desc, Blk->IsStatic, Blk->IsExtern, /*isDead=*/true) {
65  // Add the block to the chain of dead blocks.
66  if (Root)
67    Root->Prev = this;
68
69  Next = Root;
70  Prev = nullptr;
71  Root = this;
72
73  // Transfer pointers.
74  B.Pointers = Blk->Pointers;
75  for (Pointer *P = Blk->Pointers; P; P = P->Next)
76    P->Pointee = &B;
77}
78
79void DeadBlock::free() {
80  if (Prev)
81    Prev->Next = Next;
82  if (Next)
83    Next->Prev = Prev;
84  if (Root == this)
85    Root = Next;
86  ::free(this);
87}
88