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diff --git a/gdbsupport/byte-vector.h b/gdbsupport/byte-vector.h
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+/* Copyright (C) 2017-2020 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef COMMON_BYTE_VECTOR_H
+#define COMMON_BYTE_VECTOR_H
+
+#include "gdbsupport/def-vector.h"
+
+namespace gdb {
+
+/* byte_vector is a gdb_byte std::vector with a custom allocator that
+   unlike std::vector<gdb_byte> does not zero-initialize new elements
+   by default when the vector is created/resized.  This is what you
+   usually want when working with byte buffers, since if you're
+   creating or growing a buffer you'll most surely want to fill it in
+   with data, in which case zero-initialization would be a
+   pessimization.  For example:
+
+     gdb::byte_vector buf (some_large_size);
+     fill_with_data (buf.data (), buf.size ());
+
+   On the odd case you do need zero initialization, then you can still
+   call the overloads that specify an explicit value, like:
+
+     gdb::byte_vector buf (some_initial_size, 0);
+     buf.resize (a_bigger_size, 0);
+
+   (Or use std::vector<gdb_byte> instead.)
+
+   Note that unlike std::vector<gdb_byte>, function local
+   gdb::byte_vector objects constructed with an initial size like:
+
+     gdb::byte_vector buf (some_size);
+     fill_with_data (buf.data (), buf.size ());
+
+   usually compile down to the exact same as:
+
+     std::unique_ptr<byte[]> buf (new gdb_byte[some_size]);
+     fill_with_data (buf.get (), some_size);
+
+   with the former having the advantage of being a bit more readable,
+   and providing the whole std::vector API, if you end up needing it.
+*/
+using byte_vector = gdb::def_vector<gdb_byte>;
+using char_vector = gdb::def_vector<char>;
+
+} /* namespace gdb */
+
+#endif /* COMMON_DEF_VECTOR_H */