/* Poison symbols at compile time.
Copyright (C) 2017-2024 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 GDBSUPPORT_POISON_H
#define GDBSUPPORT_POISON_H
#include "traits.h"
#include "obstack.h"
/* Poison memset of non-POD types. The idea is catching invalid
initialization of non-POD structs that is easy to be introduced as
side effect of refactoring. For example, say this:
struct S { VEC(foo_s) *m_data; };
is converted to this at some point:
struct S {
S() { m_data.reserve (10); }
std::vector<foo> m_data;
};
and old code was initializing S objects like this:
struct S s;
memset (&s, 0, sizeof (S)); // whoops, now wipes vector.
Declaring memset as deleted for non-POD types makes the memset above
be a compile-time error. */
/* Helper for SFINAE. True if "T *" is memsettable. I.e., if T is
either void, or POD. */
template<typename T>
struct IsMemsettable
: gdb::Or<std::is_void<T>,
gdb::And<std::is_standard_layout<T>, std::is_trivial<T>>>
{};
template <typename T,
typename = gdb::Requires<gdb::Not<IsMemsettable<T>>>>
void *memset (T *s, int c, size_t n) = delete;
/* Similarly, poison memcpy and memmove of non trivially-copyable
types, which is undefined. */
/* True if "T *" is relocatable. I.e., copyable with memcpy/memmove.
I.e., T is either trivially copyable, or void. */
template<typename T>
struct IsRelocatable
: gdb::Or<std::is_void<T>,
std::is_trivially_copyable<T>>
{};
/* True if both source and destination are relocatable. */
template <typename D, typename S>
using BothAreRelocatable
= gdb::And<IsRelocatable<D>, IsRelocatable<S>>;
template <typename D, typename S,
typename = gdb::Requires<gdb::Not<BothAreRelocatable<D, S>>>>
void *memcpy (D *dest, const S *src, size_t n) = delete;
template <typename D, typename S,
typename = gdb::Requires<gdb::Not<BothAreRelocatable<D, S>>>>
void *memmove (D *dest, const S *src, size_t n) = delete;
/* Poison XNEW and friends to catch usages of malloc-style allocations on
objects that require new/delete. */
template<typename T>
using IsMallocable = std::is_trivially_constructible<T>;
template<typename T>
using IsFreeable = gdb::Or<std::is_trivially_destructible<T>, std::is_void<T>>;
template <typename T, typename = gdb::Requires<gdb::Not<IsFreeable<T>>>>
void free (T *ptr) = delete;
template<typename T>
static T *
xnew ()
{
static_assert (IsMallocable<T>::value, "Trying to use XNEW with a non-POD \
data type. Use operator new instead.");
return XNEW (T);
}
#undef XNEW
#define XNEW(T) xnew<T>()
template<typename T>
static T *
xcnew ()
{
static_assert (IsMallocable<T>::value, "Trying to use XCNEW with a non-POD \
data type. Use operator new instead.");
return XCNEW (T);
}
#undef XCNEW
#define XCNEW(T) xcnew<T>()
template<typename T>
static void
xdelete (T *p)
{
static_assert (IsFreeable<T>::value, "Trying to use XDELETE with a non-POD \
data type. Use operator delete instead.");
XDELETE (p);
}
#undef XDELETE
#define XDELETE(P) xdelete (P)
template<typename T>
static T *
xnewvec (size_t n)
{
static_assert (IsMallocable<T>::value, "Trying to use XNEWVEC with a \
non-POD data type. Use operator new[] (or std::vector) instead.");
return XNEWVEC (T, n);
}
#undef XNEWVEC
#define XNEWVEC(T, N) xnewvec<T> (N)
template<typename T>
static T *
xcnewvec (size_t n)
{
static_assert (IsMallocable<T>::value, "Trying to use XCNEWVEC with a \
non-POD data type. Use operator new[] (or std::vector) instead.");
return XCNEWVEC (T, n);
}
#undef XCNEWVEC
#define XCNEWVEC(T, N) xcnewvec<T> (N)
template<typename T>
static T *
xresizevec (T *p, size_t n)
{
static_assert (IsMallocable<T>::value, "Trying to use XRESIZEVEC with a \
non-POD data type.");
return XRESIZEVEC (T, p, n);
}
#undef XRESIZEVEC
#define XRESIZEVEC(T, P, N) xresizevec<T> (P, N)
template<typename T>
static void
xdeletevec (T *p)
{
static_assert (IsFreeable<T>::value, "Trying to use XDELETEVEC with a \
non-POD data type. Use operator delete[] (or std::vector) instead.");
XDELETEVEC (p);
}
#undef XDELETEVEC
#define XDELETEVEC(P) xdeletevec (P)
template<typename T>
static T *
xnewvar (size_t s)
{
static_assert (IsMallocable<T>::value, "Trying to use XNEWVAR with a \
non-POD data type.");
return XNEWVAR (T, s);;
}
#undef XNEWVAR
#define XNEWVAR(T, S) xnewvar<T> (S)
template<typename T>
static T *
xcnewvar (size_t s)
{
static_assert (IsMallocable<T>::value, "Trying to use XCNEWVAR with a \
non-POD data type.");
return XCNEWVAR (T, s);
}
#undef XCNEWVAR
#define XCNEWVAR(T, S) xcnewvar<T> (S)
template<typename T>
static T *
xresizevar (T *p, size_t s)
{
static_assert (IsMallocable<T>::value, "Trying to use XRESIZEVAR with a \
non-POD data type.");
return XRESIZEVAR (T, p, s);
}
#undef XRESIZEVAR
#define XRESIZEVAR(T, P, S) xresizevar<T> (P, S)
template<typename T>
static T *
xobnew (obstack *ob)
{
static_assert (IsMallocable<T>::value, "Trying to use XOBNEW with a \
non-POD data type.");
return XOBNEW (ob, T);
}
#undef XOBNEW
#define XOBNEW(O, T) xobnew<T> (O)
template<typename T>
static T *
xobnewvec (obstack *ob, size_t n)
{
static_assert (IsMallocable<T>::value, "Trying to use XOBNEWVEC with a \
non-POD data type.");
return XOBNEWVEC (ob, T, n);
}
#undef XOBNEWVEC
#define XOBNEWVEC(O, T, N) xobnewvec<T> (O, N)
#endif /* GDBSUPPORT_POISON_H */
