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
addPointer(Pointer * P)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
removePointer(Pointer * P)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
cleanup()56 void Block::cleanup() {
57 if (Pointers == nullptr && IsDead)
58 (reinterpret_cast<DeadBlock *>(this + 1) - 1)->free();
59 }
60
replacePointer(Pointer * Old,Pointer * New)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(Old);
74 addPointer(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
hasPointer(const Pointer * P) const85 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
DeadBlock(DeadBlock * & Root,Block * Blk)94 DeadBlock::DeadBlock(DeadBlock *&Root, Block *Blk)
95 : Root(Root),
96 B(~0u, Blk->Desc, Blk->IsStatic, Blk->IsExtern, /*isDead=*/true) {
97 // Add the block to the chain of dead blocks.
98 if (Root)
99 Root->Prev = this;
100
101 Next = Root;
102 Prev = nullptr;
103 Root = this;
104
105 // Transfer pointers.
106 B.Pointers = Blk->Pointers;
107 for (Pointer *P = Blk->Pointers; P; P = P->Next)
108 P->PointeeStorage.BS.Pointee = &B;
109 Blk->Pointers = nullptr;
110 }
111
free()112 void DeadBlock::free() {
113 if (B.IsInitialized)
114 B.invokeDtor();
115
116 if (Prev)
117 Prev->Next = Next;
118 if (Next)
119 Next->Prev = Prev;
120 if (Root == this)
121 Root = Next;
122 std::free(this);
123 }
124