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69 lines
2.3 KiB
C
69 lines
2.3 KiB
C
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/* Copyright (C) 2022 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#ifndef COMMON_GDB_CHECKED_DYNAMIC_CAST_H
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#define COMMON_GDB_CHECKED_DYNAMIC_CAST_H
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#include "gdbsupport/traits.h"
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namespace gdb
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{
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/* This function can be used in place of static_cast when casting between
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pointers of polymorphic types. The benefit of using this call is that,
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when compiling in developer mode, dynamic_cast will be used to validate
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the cast. This use of dynamic_cast is why this function will only
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work for polymorphic types.
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In non-developer (i.e. production) builds, the dynamic_cast is replaced
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with a static_cast which is usually significantly faster. */
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template<typename T, typename V>
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T
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checked_static_cast (V *v)
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{
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/* We only support casting to pointer types. */
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static_assert (std::is_pointer<T>::value, "target must be a pointer type");
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/* Check for polymorphic types explicitly in case we're in release mode. */
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static_assert (std::is_polymorphic<V>::value, "types must be polymorphic");
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/* Figure out the type that T points to. */
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using T_no_P = typename std::remove_pointer<T>::type;
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/* In developer mode this cast uses dynamic_cast to confirm at run-time
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that the cast from V* to T is valid. However, we can catch some
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mistakes at compile time, this assert prevents anything other than
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downcasts, or casts to same type. */
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static_assert (std::is_base_of<V, T_no_P>::value
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|| std::is_base_of<T_no_P, V>::value,
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"types must be related");
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#ifdef DEVELOPMENT
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T result = dynamic_cast<T> (v);
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gdb_assert (result != nullptr);
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#else
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T result = static_cast<T> (v);
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#endif
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return result;
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}
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}
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#endif /* COMMON_GDB_CHECKED_DYNAMIC_CAST_H */
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