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Diffstat (limited to 'lib/AST/Interp/Block.h')
-rw-r--r-- | lib/AST/Interp/Block.h | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/lib/AST/Interp/Block.h b/lib/AST/Interp/Block.h new file mode 100644 index 000000000000..97fb9a3ca096 --- /dev/null +++ b/lib/AST/Interp/Block.h @@ -0,0 +1,140 @@ +//===--- Block.h - Allocated blocks for the interpreter ---------*- C++ -*-===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// Defines the classes describing allocated blocks. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_CLANG_AST_INTERP_BLOCK_H +#define LLVM_CLANG_AST_INTERP_BLOCK_H + +#include "Descriptor.h" +#include "clang/AST/Decl.h" +#include "clang/AST/DeclCXX.h" +#include "clang/AST/Expr.h" +#include "clang/AST/ComparisonCategories.h" +#include "llvm/ADT/PointerUnion.h" +#include "llvm/Support/raw_ostream.h" + +namespace clang { +namespace interp { +class Block; +class DeadBlock; +class Context; +class InterpState; +class Pointer; +class Function; +enum PrimType : unsigned; + +/// A memory block, either on the stack or in the heap. +/// +/// The storage described by the block immediately follows it in memory. +class Block { +public: + // Creates a new block. + Block(const llvm::Optional<unsigned> &DeclID, Descriptor *Desc, + bool IsStatic = false, bool IsExtern = false) + : DeclID(DeclID), IsStatic(IsStatic), IsExtern(IsExtern), Desc(Desc) {} + + Block(Descriptor *Desc, bool IsStatic = false, bool IsExtern = false) + : DeclID((unsigned)-1), IsStatic(IsStatic), IsExtern(IsExtern), + Desc(Desc) {} + + /// Returns the block's descriptor. + Descriptor *getDescriptor() const { return Desc; } + /// Checks if the block has any live pointers. + bool hasPointers() const { return Pointers; } + /// Checks if the block is extern. + bool isExtern() const { return IsExtern; } + /// Checks if the block has static storage duration. + bool isStatic() const { return IsStatic; } + /// Checks if the block is temporary. + bool isTemporary() const { return Desc->IsTemporary; } + /// Returns the size of the block. + InterpSize getSize() const { return Desc->getAllocSize(); } + /// Returns the declaration ID. + llvm::Optional<unsigned> getDeclID() const { return DeclID; } + + /// Returns a pointer to the stored data. + char *data() { return reinterpret_cast<char *>(this + 1); } + + /// Returns a view over the data. + template <typename T> + T &deref() { return *reinterpret_cast<T *>(data()); } + + /// Invokes the constructor. + void invokeCtor() { + std::memset(data(), 0, getSize()); + if (Desc->CtorFn) + Desc->CtorFn(this, data(), Desc->IsConst, Desc->IsMutable, + /*isActive=*/true, Desc); + } + +protected: + friend class Pointer; + friend class DeadBlock; + friend class InterpState; + + Block(Descriptor *Desc, bool IsExtern, bool IsStatic, bool IsDead) + : IsStatic(IsStatic), IsExtern(IsExtern), IsDead(true), Desc(Desc) {} + + // Deletes a dead block at the end of its lifetime. + void cleanup(); + + // Pointer chain management. + void addPointer(Pointer *P); + void removePointer(Pointer *P); + void movePointer(Pointer *From, Pointer *To); + + /// Start of the chain of pointers. + Pointer *Pointers = nullptr; + /// Unique identifier of the declaration. + llvm::Optional<unsigned> DeclID; + /// Flag indicating if the block has static storage duration. + bool IsStatic = false; + /// Flag indicating if the block is an extern. + bool IsExtern = false; + /// Flag indicating if the pointer is dead. + bool IsDead = false; + /// Pointer to the stack slot descriptor. + Descriptor *Desc; +}; + +/// Descriptor for a dead block. +/// +/// Dead blocks are chained in a double-linked list to deallocate them +/// whenever pointers become dead. +class DeadBlock { +public: + /// Copies the block. + DeadBlock(DeadBlock *&Root, Block *Blk); + + /// Returns a pointer to the stored data. + char *data() { return B.data(); } + +private: + friend class Block; + friend class InterpState; + + void free(); + + /// Root pointer of the list. + DeadBlock *&Root; + /// Previous block in the list. + DeadBlock *Prev; + /// Next block in the list. + DeadBlock *Next; + + /// Actual block storing data and tracking pointers. + Block B; +}; + +} // namespace interp +} // namespace clang + +#endif |