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InterpBlock.cpp revision 1.1 
      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 
     20 
     21 void 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 
     31 void 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 
     42 void Block::cleanup() {
     43   if (Pointers == nullptr && IsDead)
     44     (reinterpret_cast<DeadBlock *>(this + 1) - 1)->free();
     45 }
     46 
     47 void 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 
     63 DeadBlock::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 
     79 void 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