1 //==-------- DynamicAllocator.cpp - Dynamic allocations ----------*- 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 #include "DynamicAllocator.h" 10 #include "InterpBlock.h" 11 #include "InterpState.h" 12 13 using namespace clang; 14 using namespace clang::interp; 15 16 DynamicAllocator::~DynamicAllocator() { cleanup(); } 17 18 void DynamicAllocator::cleanup() { 19 // Invoke destructors of all the blocks and as a last restort, 20 // reset all the pointers pointing to them to null pointees. 21 // This should never show up in diagnostics, but it's necessary 22 // for us to not cause use-after-free problems. 23 for (auto &Iter : AllocationSites) { 24 auto &AllocSite = Iter.second; 25 for (auto &Alloc : AllocSite.Allocations) { 26 Block *B = reinterpret_cast<Block *>(Alloc.Memory.get()); 27 B->invokeDtor(); 28 if (B->hasPointers()) { 29 while (B->Pointers) { 30 Pointer *Next = B->Pointers->Next; 31 B->Pointers->PointeeStorage.BS.Pointee = nullptr; 32 B->Pointers = Next; 33 } 34 B->Pointers = nullptr; 35 } 36 } 37 } 38 39 AllocationSites.clear(); 40 } 41 42 Block *DynamicAllocator::allocate(const Expr *Source, PrimType T, 43 size_t NumElements, unsigned EvalID, 44 Form AllocForm) { 45 // Create a new descriptor for an array of the specified size and 46 // element type. 47 const Descriptor *D = allocateDescriptor( 48 Source, T, Descriptor::InlineDescMD, NumElements, /*IsConst=*/false, 49 /*IsTemporary=*/false, /*IsMutable=*/false); 50 51 return allocate(D, EvalID, AllocForm); 52 } 53 54 Block *DynamicAllocator::allocate(const Descriptor *ElementDesc, 55 size_t NumElements, unsigned EvalID, 56 Form AllocForm) { 57 // Create a new descriptor for an array of the specified size and 58 // element type. 59 const Descriptor *D = allocateDescriptor( 60 ElementDesc->asExpr(), ElementDesc, Descriptor::InlineDescMD, NumElements, 61 /*IsConst=*/false, /*IsTemporary=*/false, /*IsMutable=*/false); 62 return allocate(D, EvalID, AllocForm); 63 } 64 65 Block *DynamicAllocator::allocate(const Descriptor *D, unsigned EvalID, 66 Form AllocForm) { 67 assert(D); 68 assert(D->asExpr()); 69 70 auto Memory = 71 std::make_unique<std::byte[]>(sizeof(Block) + D->getAllocSize()); 72 auto *B = new (Memory.get()) Block(EvalID, D, /*isStatic=*/false); 73 B->invokeCtor(); 74 75 InlineDescriptor *ID = reinterpret_cast<InlineDescriptor *>(B->rawData()); 76 ID->Desc = D; 77 ID->IsActive = true; 78 ID->Offset = sizeof(InlineDescriptor); 79 ID->IsBase = false; 80 ID->IsFieldMutable = false; 81 ID->IsConst = false; 82 ID->IsInitialized = false; 83 84 B->IsDynamic = true; 85 86 if (auto It = AllocationSites.find(D->asExpr()); It != AllocationSites.end()) 87 It->second.Allocations.emplace_back(std::move(Memory)); 88 else 89 AllocationSites.insert( 90 {D->asExpr(), AllocationSite(std::move(Memory), AllocForm)}); 91 return B; 92 } 93 94 bool DynamicAllocator::deallocate(const Expr *Source, 95 const Block *BlockToDelete, InterpState &S) { 96 auto It = AllocationSites.find(Source); 97 if (It == AllocationSites.end()) 98 return false; 99 100 auto &Site = It->second; 101 assert(Site.size() > 0); 102 103 // Find the Block to delete. 104 auto AllocIt = llvm::find_if(Site.Allocations, [&](const Allocation &A) { 105 const Block *B = reinterpret_cast<const Block *>(A.Memory.get()); 106 return BlockToDelete == B; 107 }); 108 109 assert(AllocIt != Site.Allocations.end()); 110 111 Block *B = reinterpret_cast<Block *>(AllocIt->Memory.get()); 112 B->invokeDtor(); 113 114 S.deallocate(B); 115 Site.Allocations.erase(AllocIt); 116 117 if (Site.size() == 0) 118 AllocationSites.erase(It); 119 120 return true; 121 } 122