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b72788c27a
This adds the `__swift::__runtime` inline namespace to the LLVMSupport interfaces. This avoids an ODR violation when LLVM and Swift are in the same address space. It also will aid in the process of pruning the LLVMSupport library by ensuring that accidental leakage of the llvm namespace does not allow us to remove symbols which we rely on.
403 lines
14 KiB
C++
403 lines
14 KiB
C++
//===- llvm/Support/Casting.h - Allow flexible, checked, casts --*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines the isa<X>(), cast<X>(), dyn_cast<X>(), cast_or_null<X>(),
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// and dyn_cast_or_null<X>() templates.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_SUPPORT_CASTING_H
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#define LLVM_SUPPORT_CASTING_H
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#include "llvm/Support/Compiler.h"
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#include "llvm/Support/type_traits.h"
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#include <cassert>
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#include <memory>
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#include <type_traits>
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inline namespace __swift { inline namespace __runtime {
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namespace llvm {
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//===----------------------------------------------------------------------===//
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// isa<x> Support Templates
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//===----------------------------------------------------------------------===//
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// Define a template that can be specialized by smart pointers to reflect the
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// fact that they are automatically dereferenced, and are not involved with the
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// template selection process... the default implementation is a noop.
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//
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template<typename From> struct simplify_type {
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using SimpleType = From; // The real type this represents...
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// An accessor to get the real value...
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static SimpleType &getSimplifiedValue(From &Val) { return Val; }
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};
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template<typename From> struct simplify_type<const From> {
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using NonConstSimpleType = typename simplify_type<From>::SimpleType;
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using SimpleType =
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typename add_const_past_pointer<NonConstSimpleType>::type;
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using RetType =
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typename add_lvalue_reference_if_not_pointer<SimpleType>::type;
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static RetType getSimplifiedValue(const From& Val) {
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return simplify_type<From>::getSimplifiedValue(const_cast<From&>(Val));
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}
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};
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// The core of the implementation of isa<X> is here; To and From should be
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// the names of classes. This template can be specialized to customize the
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// implementation of isa<> without rewriting it from scratch.
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template <typename To, typename From, typename Enabler = void>
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struct isa_impl {
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static inline bool doit(const From &Val) {
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return To::classof(&Val);
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}
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};
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/// Always allow upcasts, and perform no dynamic check for them.
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template <typename To, typename From>
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struct isa_impl<To, From, std::enable_if_t<std::is_base_of<To, From>::value>> {
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static inline bool doit(const From &) { return true; }
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};
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template <typename To, typename From> struct isa_impl_cl {
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static inline bool doit(const From &Val) {
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return isa_impl<To, From>::doit(Val);
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}
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};
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template <typename To, typename From> struct isa_impl_cl<To, const From> {
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static inline bool doit(const From &Val) {
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return isa_impl<To, From>::doit(Val);
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}
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};
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template <typename To, typename From>
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struct isa_impl_cl<To, const std::unique_ptr<From>> {
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static inline bool doit(const std::unique_ptr<From> &Val) {
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assert(Val && "isa<> used on a null pointer");
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return isa_impl_cl<To, From>::doit(*Val);
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}
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};
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template <typename To, typename From> struct isa_impl_cl<To, From*> {
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static inline bool doit(const From *Val) {
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assert(Val && "isa<> used on a null pointer");
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return isa_impl<To, From>::doit(*Val);
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}
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};
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template <typename To, typename From> struct isa_impl_cl<To, From*const> {
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static inline bool doit(const From *Val) {
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assert(Val && "isa<> used on a null pointer");
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return isa_impl<To, From>::doit(*Val);
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}
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};
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template <typename To, typename From> struct isa_impl_cl<To, const From*> {
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static inline bool doit(const From *Val) {
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assert(Val && "isa<> used on a null pointer");
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return isa_impl<To, From>::doit(*Val);
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}
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};
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template <typename To, typename From> struct isa_impl_cl<To, const From*const> {
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static inline bool doit(const From *Val) {
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assert(Val && "isa<> used on a null pointer");
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return isa_impl<To, From>::doit(*Val);
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}
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};
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template<typename To, typename From, typename SimpleFrom>
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struct isa_impl_wrap {
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// When From != SimplifiedType, we can simplify the type some more by using
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// the simplify_type template.
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static bool doit(const From &Val) {
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return isa_impl_wrap<To, SimpleFrom,
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typename simplify_type<SimpleFrom>::SimpleType>::doit(
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simplify_type<const From>::getSimplifiedValue(Val));
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}
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};
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template<typename To, typename FromTy>
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struct isa_impl_wrap<To, FromTy, FromTy> {
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// When From == SimpleType, we are as simple as we are going to get.
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static bool doit(const FromTy &Val) {
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return isa_impl_cl<To,FromTy>::doit(Val);
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}
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};
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// isa<X> - Return true if the parameter to the template is an instance of the
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// template type argument. Used like this:
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//
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// if (isa<Type>(myVal)) { ... }
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//
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template <class X, class Y> LLVM_NODISCARD inline bool isa(const Y &Val) {
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return isa_impl_wrap<X, const Y,
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typename simplify_type<const Y>::SimpleType>::doit(Val);
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}
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// isa_and_nonnull<X> - Functionally identical to isa, except that a null value
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// is accepted.
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//
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template <class X, class Y>
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LLVM_NODISCARD inline bool isa_and_nonnull(const Y &Val) {
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if (!Val)
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return false;
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return isa<X>(Val);
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}
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//===----------------------------------------------------------------------===//
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// cast<x> Support Templates
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//===----------------------------------------------------------------------===//
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template<class To, class From> struct cast_retty;
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// Calculate what type the 'cast' function should return, based on a requested
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// type of To and a source type of From.
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template<class To, class From> struct cast_retty_impl {
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using ret_type = To &; // Normal case, return Ty&
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};
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template<class To, class From> struct cast_retty_impl<To, const From> {
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using ret_type = const To &; // Normal case, return Ty&
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};
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template<class To, class From> struct cast_retty_impl<To, From*> {
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using ret_type = To *; // Pointer arg case, return Ty*
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};
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template<class To, class From> struct cast_retty_impl<To, const From*> {
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using ret_type = const To *; // Constant pointer arg case, return const Ty*
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};
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template<class To, class From> struct cast_retty_impl<To, const From*const> {
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using ret_type = const To *; // Constant pointer arg case, return const Ty*
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};
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template <class To, class From>
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struct cast_retty_impl<To, std::unique_ptr<From>> {
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private:
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using PointerType = typename cast_retty_impl<To, From *>::ret_type;
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using ResultType = std::remove_pointer_t<PointerType>;
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public:
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using ret_type = std::unique_ptr<ResultType>;
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};
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template<class To, class From, class SimpleFrom>
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struct cast_retty_wrap {
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// When the simplified type and the from type are not the same, use the type
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// simplifier to reduce the type, then reuse cast_retty_impl to get the
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// resultant type.
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using ret_type = typename cast_retty<To, SimpleFrom>::ret_type;
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};
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template<class To, class FromTy>
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struct cast_retty_wrap<To, FromTy, FromTy> {
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// When the simplified type is equal to the from type, use it directly.
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using ret_type = typename cast_retty_impl<To,FromTy>::ret_type;
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};
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template<class To, class From>
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struct cast_retty {
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using ret_type = typename cast_retty_wrap<
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To, From, typename simplify_type<From>::SimpleType>::ret_type;
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};
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// Ensure the non-simple values are converted using the simplify_type template
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// that may be specialized by smart pointers...
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//
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template<class To, class From, class SimpleFrom> struct cast_convert_val {
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// This is not a simple type, use the template to simplify it...
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static typename cast_retty<To, From>::ret_type doit(From &Val) {
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return cast_convert_val<To, SimpleFrom,
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typename simplify_type<SimpleFrom>::SimpleType>::doit(
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simplify_type<From>::getSimplifiedValue(Val));
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}
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};
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template<class To, class FromTy> struct cast_convert_val<To,FromTy,FromTy> {
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// This _is_ a simple type, just cast it.
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static typename cast_retty<To, FromTy>::ret_type doit(const FromTy &Val) {
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typename cast_retty<To, FromTy>::ret_type Res2
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= (typename cast_retty<To, FromTy>::ret_type)const_cast<FromTy&>(Val);
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return Res2;
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}
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};
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template <class X> struct is_simple_type {
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static const bool value =
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std::is_same<X, typename simplify_type<X>::SimpleType>::value;
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};
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// cast<X> - Return the argument parameter cast to the specified type. This
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// casting operator asserts that the type is correct, so it does not return null
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// on failure. It does not allow a null argument (use cast_or_null for that).
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// It is typically used like this:
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//
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// cast<Instruction>(myVal)->getParent()
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//
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template <class X, class Y>
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inline std::enable_if_t<!is_simple_type<Y>::value,
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typename cast_retty<X, const Y>::ret_type>
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cast(const Y &Val) {
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assert(isa<X>(Val) && "cast<Ty>() argument of incompatible type!");
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return cast_convert_val<
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X, const Y, typename simplify_type<const Y>::SimpleType>::doit(Val);
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}
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template <class X, class Y>
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inline typename cast_retty<X, Y>::ret_type cast(Y &Val) {
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assert(isa<X>(Val) && "cast<Ty>() argument of incompatible type!");
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return cast_convert_val<X, Y,
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typename simplify_type<Y>::SimpleType>::doit(Val);
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}
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template <class X, class Y>
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inline typename cast_retty<X, Y *>::ret_type cast(Y *Val) {
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assert(isa<X>(Val) && "cast<Ty>() argument of incompatible type!");
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return cast_convert_val<X, Y*,
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typename simplify_type<Y*>::SimpleType>::doit(Val);
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}
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template <class X, class Y>
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inline typename cast_retty<X, std::unique_ptr<Y>>::ret_type
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cast(std::unique_ptr<Y> &&Val) {
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assert(isa<X>(Val.get()) && "cast<Ty>() argument of incompatible type!");
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using ret_type = typename cast_retty<X, std::unique_ptr<Y>>::ret_type;
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return ret_type(
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cast_convert_val<X, Y *, typename simplify_type<Y *>::SimpleType>::doit(
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Val.release()));
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}
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// cast_or_null<X> - Functionally identical to cast, except that a null value is
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// accepted.
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//
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template <class X, class Y>
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LLVM_NODISCARD inline std::enable_if_t<
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!is_simple_type<Y>::value, typename cast_retty<X, const Y>::ret_type>
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cast_or_null(const Y &Val) {
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if (!Val)
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return nullptr;
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assert(isa<X>(Val) && "cast_or_null<Ty>() argument of incompatible type!");
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return cast<X>(Val);
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}
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template <class X, class Y>
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LLVM_NODISCARD inline std::enable_if_t<!is_simple_type<Y>::value,
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typename cast_retty<X, Y>::ret_type>
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cast_or_null(Y &Val) {
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if (!Val)
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return nullptr;
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assert(isa<X>(Val) && "cast_or_null<Ty>() argument of incompatible type!");
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return cast<X>(Val);
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}
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template <class X, class Y>
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LLVM_NODISCARD inline typename cast_retty<X, Y *>::ret_type
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cast_or_null(Y *Val) {
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if (!Val) return nullptr;
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assert(isa<X>(Val) && "cast_or_null<Ty>() argument of incompatible type!");
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return cast<X>(Val);
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}
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template <class X, class Y>
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inline typename cast_retty<X, std::unique_ptr<Y>>::ret_type
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cast_or_null(std::unique_ptr<Y> &&Val) {
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if (!Val)
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return nullptr;
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return cast<X>(std::move(Val));
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}
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// dyn_cast<X> - Return the argument parameter cast to the specified type. This
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// casting operator returns null if the argument is of the wrong type, so it can
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// be used to test for a type as well as cast if successful. This should be
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// used in the context of an if statement like this:
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//
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// if (const Instruction *I = dyn_cast<Instruction>(myVal)) { ... }
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//
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template <class X, class Y>
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LLVM_NODISCARD inline std::enable_if_t<
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!is_simple_type<Y>::value, typename cast_retty<X, const Y>::ret_type>
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dyn_cast(const Y &Val) {
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return isa<X>(Val) ? cast<X>(Val) : nullptr;
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}
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template <class X, class Y>
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LLVM_NODISCARD inline typename cast_retty<X, Y>::ret_type dyn_cast(Y &Val) {
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return isa<X>(Val) ? cast<X>(Val) : nullptr;
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}
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template <class X, class Y>
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LLVM_NODISCARD inline typename cast_retty<X, Y *>::ret_type dyn_cast(Y *Val) {
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return isa<X>(Val) ? cast<X>(Val) : nullptr;
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}
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// dyn_cast_or_null<X> - Functionally identical to dyn_cast, except that a null
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// value is accepted.
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//
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template <class X, class Y>
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LLVM_NODISCARD inline std::enable_if_t<
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!is_simple_type<Y>::value, typename cast_retty<X, const Y>::ret_type>
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dyn_cast_or_null(const Y &Val) {
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return (Val && isa<X>(Val)) ? cast<X>(Val) : nullptr;
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}
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template <class X, class Y>
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LLVM_NODISCARD inline std::enable_if_t<!is_simple_type<Y>::value,
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typename cast_retty<X, Y>::ret_type>
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dyn_cast_or_null(Y &Val) {
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return (Val && isa<X>(Val)) ? cast<X>(Val) : nullptr;
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}
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template <class X, class Y>
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LLVM_NODISCARD inline typename cast_retty<X, Y *>::ret_type
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dyn_cast_or_null(Y *Val) {
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return (Val && isa<X>(Val)) ? cast<X>(Val) : nullptr;
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}
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// unique_dyn_cast<X> - Given a unique_ptr<Y>, try to return a unique_ptr<X>,
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// taking ownership of the input pointer iff isa<X>(Val) is true. If the
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// cast is successful, From refers to nullptr on exit and the casted value
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// is returned. If the cast is unsuccessful, the function returns nullptr
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// and From is unchanged.
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template <class X, class Y>
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LLVM_NODISCARD inline auto unique_dyn_cast(std::unique_ptr<Y> &Val)
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-> decltype(cast<X>(Val)) {
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if (!isa<X>(Val))
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return nullptr;
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return cast<X>(std::move(Val));
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}
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template <class X, class Y>
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LLVM_NODISCARD inline auto unique_dyn_cast(std::unique_ptr<Y> &&Val) {
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return unique_dyn_cast<X, Y>(Val);
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}
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// dyn_cast_or_null<X> - Functionally identical to unique_dyn_cast, except that
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// a null value is accepted.
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template <class X, class Y>
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LLVM_NODISCARD inline auto unique_dyn_cast_or_null(std::unique_ptr<Y> &Val)
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-> decltype(cast<X>(Val)) {
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if (!Val)
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return nullptr;
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return unique_dyn_cast<X, Y>(Val);
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}
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template <class X, class Y>
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LLVM_NODISCARD inline auto unique_dyn_cast_or_null(std::unique_ptr<Y> &&Val) {
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return unique_dyn_cast_or_null<X, Y>(Val);
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}
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} // end namespace llvm
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}} // namespace swift::runtime
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#endif // LLVM_SUPPORT_CASTING_H
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