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
16using namespace clang;
17using namespace clang::interp;
18
19void 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#ifndef NDEBUG
35 assert(hasPointer(P));
36#endif
37}
38
39void Block::removePointer(Pointer *P) {
40 assert(P->isBlockPointer());
41 assert(P);
42 if (IsStatic) {
43 assert(!Pointers);
44 return;
45 }
46
47#ifndef NDEBUG
48 assert(hasPointer(P));
49#endif
50
51 if (Pointers == P)
52 Pointers = P->Next;
53
54 if (P->Prev)
55 P->Prev->Next = P->Next;
56 if (P->Next)
57 P->Next->Prev = P->Prev;
58 P->PointeeStorage.BS.Pointee = nullptr;
59#ifndef NDEBUG
60 assert(!hasPointer(P));
61#endif
62}
63
64void Block::cleanup() {
65 if (Pointers == nullptr && IsDead)
66 (reinterpret_cast<DeadBlock *>(this + 1) - 1)->free();
67}
68
69void Block::replacePointer(Pointer *Old, Pointer *New) {
70 assert(Old);
71 assert(New);
72 assert(Old != New);
73 if (IsStatic) {
74 assert(!Pointers);
75 return;
76 }
77#ifndef NDEBUG
78 assert(hasPointer(Old));
79#endif
80
81 if (Old->Prev)
82 Old->Prev->Next = New;
83 if (Old->Next)
84 Old->Next->Prev = New;
85 New->Prev = Old->Prev;
86 New->Next = Old->Next;
87 if (Pointers == Old)
88 Pointers = New;
89
90 Old->PointeeStorage.BS.Pointee = nullptr;
91 New->PointeeStorage.BS.Pointee = this;
92#ifndef NDEBUG
93 assert(!hasPointer(Old));
94 assert(hasPointer(New));
95#endif
96}
97
98#ifndef NDEBUG
99bool Block::hasPointer(const Pointer *P) const {
100 for (const Pointer *C = Pointers; C; C = C->Next) {
101 if (C == P)
102 return true;
103 }
104 return false;
105}
106#endif
107
108DeadBlock::DeadBlock(DeadBlock *&Root, Block *Blk)
109 : Root(Root), B(~0u, Blk->Desc, Blk->IsStatic, Blk->IsExtern, Blk->IsWeak,
110 /*isDead=*/true) {
111 // Add the block to the chain of dead blocks.
112 if (Root)
113 Root->Prev = this;
114
115 Next = Root;
116 Prev = nullptr;
117 Root = this;
118
119 B.IsDynamic = Blk->IsDynamic;
120
121 // Transfer pointers.
122 B.Pointers = Blk->Pointers;
123 for (Pointer *P = Blk->Pointers; P; P = P->Next)
124 P->PointeeStorage.BS.Pointee = &B;
125 Blk->Pointers = nullptr;
126}
127
128void DeadBlock::free() {
129 if (B.IsInitialized)
130 B.invokeDtor();
131
132 if (Prev)
133 Prev->Next = Next;
134 if (Next)
135 Next->Prev = Prev;
136 if (Root == this)
137 Root = Next;
138 std::free(ptr: this);
139}
140