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Delete gdb::unique_ptr/gdb::move

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Now that we require C++11 and all uses of gdb::unique_ptr and
gdb::move are gone, let's remove their definitions...

With my lazy hat on, I repurposed the header for "generally useful
unique_ptr specializations", and left gdb::unique_xmalloc_ptr in
there.  Not sure whether we it'd be better move it out of the gdb
namespace or leave it be.  I left it because it's less work and avoids
disrupting yet-unmerged patches that use it.

gdb/ChangeLog:
2016-11-15  Pedro Alves  <palves@redhat.com>

	* common/common-defs.h: Update comment.
	* common/gdb_unique_ptr.h: Update header comment and copyright
	year.
	(gdb::unique_ptr, gdb::move): Delete.
This commit is contained in:
Pedro Alves 2016-11-15 19:54:21 +00:00
parent b22e99fdaf
commit 5cc8c73103
3 changed files with 14 additions and 348 deletions
Download patch file Download diff file Expand all files Collapse all files

7
gdb/ChangeLog
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@ -1,3 +1,10 @@
2016-11-15 Pedro Alves <palves@redhat.com>
* common/common-defs.h: Update comment.
* common/gdb_unique_ptr.h: Update header comment and copyright
year.
(gdb::unique_ptr, gdb::move): Delete.
2016-11-15 Pedro Alves <palves@redhat.com> 2016-11-15 Pedro Alves <palves@redhat.com>
* ada-lang.c (create_excep_cond_exprs): Use std::move instead of * ada-lang.c (create_excep_cond_exprs): Use std::move instead of

2
gdb/common/common-defs.h
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@ -87,7 +87,7 @@
#define EXTERN_C_PUSH extern "C" { #define EXTERN_C_PUSH extern "C" {
#define EXTERN_C_POP } #define EXTERN_C_POP }
/* Pull in gdb::unique_ptr and gdb::unique_xmalloc_ptr. */ /* Pull in gdb::unique_xmalloc_ptr. */
#include "common/gdb_unique_ptr.h" #include "common/gdb_unique_ptr.h"
#endif /* COMMON_DEFS_H */ #endif /* COMMON_DEFS_H */

353
gdb/common/gdb_unique_ptr.h
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@ -1,6 +1,6 @@
/* gdb::unique_ptr, a simple std::unique_ptr replacement for C++03. /* std::unique_ptr specializations for GDB.
Copyright (C) 2007-2016 Free Software Foundation, Inc. Copyright (C) 2016 Free Software Foundation, Inc.
This file is part of GDB. This file is part of GDB.
@ -17,60 +17,6 @@
You should have received a copy of the GNU General Public License You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */ along with this program. If not, see <http://www.gnu.org/licenses/>. */
/* gdb::unique_ptr defines a C++ owning smart pointer that exposes a
subset of the std::unique_ptr API.
In fact, when compiled with a C++11 compiler, gdb::unique_ptr
actually _is_ std::unique_ptr. When compiled with a C++03 compiler
OTOH, it's an hand coded std::unique_ptr emulation that assumes
code is correct and doesn't try to be too smart.
This supports custom deleters, but not _stateful_ deleters, so you
can't use those in C++11 mode either. Only the managed pointer is
stored in the smart pointer. That could be changed; it simply
wasn't found necessary.
At the end of the file you'll find a gdb::unique_ptr partial
specialization that uses a custom (stateless) deleter:
gdb::unique_xmalloc_ptr. That is used to manage pointers to
objects allocated with xmalloc.
The C++03 version was originally based on GCC 7.0's std::auto_ptr
and then heavily customized to behave more like C++11's
std::unique_ptr, but at this point, it no longer shares much at all
with the original file. But, that's the history and the reason for
the copyright's starting year.
The C++03 version lets you shoot yourself in the foot, since
similarly to std::auto_ptr, the copy constructor and assignment
operators actually move. Also, in the name of simplicity, no
effort is spent on using SFINAE to prevent invalid conversions,
etc. This is not really a problem, because the goal here is to
allow code that would be correct using std::unique_ptr to be
equally correct in C++03 mode, and, just as efficient. If client
code compiles correctly with a C++11 (or newer) compiler, we know
we're not doing anything invalid by mistake.
Usage notes:
- Putting gdb::unique_ptr in standard containers is not supported,
since C++03 containers are not move-aware (and our emulation
relies on copy actually moving).
- Since there's no nullptr in C++03, gdb::unique_ptr allows
implicit initialization and assignment from NULL instead.
- To check whether there's an associated managed object, all these
work as expected:
if (ptr)
if (!ptr)
if (ptr != NULL)
if (ptr == NULL)
if (NULL != ptr)
if (NULL == ptr)
*/
#ifndef GDB_UNIQUE_PTR_H #ifndef GDB_UNIQUE_PTR_H
#define GDB_UNIQUE_PTR_H 1 #define GDB_UNIQUE_PTR_H 1
@ -78,309 +24,22 @@
namespace gdb namespace gdb
{ {
/* Define gdb::unique_xmalloc_ptr, a std::unique_ptr that manages
#if __cplusplus >= 201103
/* In C++11 mode, all we need is import the standard
std::unique_ptr. */
template<typename T> using unique_ptr = std::unique_ptr<T>;
/* Pull in move as well. */
using std::move;
#else /* C++11 */
/* Default destruction policy used by gdb::unique_ptr when no deleter
is specified. Uses delete. */
template<typename T>
struct default_delete
{
void operator () (T *ptr) const { delete ptr; }
};
/* Specialization for arrays. Uses delete[]. */
template<typename T>
struct default_delete<T[]>
{
void operator () (T *ptr) const { delete [] ptr; }
};
namespace detail
{
/* Type used to support implicit construction from NULL:
gdb::unique_ptr<foo> func (....)
{
return NULL;
}
and assignment from NULL:
gdb::unique_ptr<foo> ptr (....);
...
ptr = NULL;
It is intentionally not defined anywhere. */
struct nullptr_t;
/* Base class of our unique_ptr emulation. Contains code common to
both unique_ptr<T, D> and unique_ptr<T[], D>. */
template<typename T, typename D>
class unique_ptr_base
{
public:
typedef T *pointer;
typedef T element_type;
typedef D deleter_type;
/* Takes ownership of a pointer. P is a pointer to an object of
element_type type. Defaults to NULL. */
explicit unique_ptr_base (element_type *p = NULL) throw () : m_ptr (p) {}
/* The "move" constructor. Really a copy constructor that actually
moves. Even though std::unique_ptr is not copyable, our little
simpler emulation allows it, because:
- There are no rvalue references in C++03. Our move emulation
instead relies on copy/assignment moving, like std::auto_ptr.
- RVO/NRVO requires an accessible copy constructor
*/
unique_ptr_base (const unique_ptr_base &other) throw ()
: m_ptr (const_cast<unique_ptr_base &> (other).release ()) {}
/* Converting "move" constructor. Really an lvalue ref converting
constructor that actually moves. This allows constructs such as:
unique_ptr<Derived> func_returning_unique_ptr (.....);
...
unique_ptr<Base> ptr = func_returning_unique_ptr (.....);
*/
template<typename T1, typename D1>
unique_ptr_base (const unique_ptr_base<T1, D1> &other) throw ()
: m_ptr (const_cast<unique_ptr_base<T1, D1> &> (other).release ()) {}
/* The "move" assignment operator. Really an lvalue ref copy
assignment operator that actually moves. See comments above. */
unique_ptr_base &operator= (const unique_ptr_base &other) throw ()
{
reset (const_cast<unique_ptr_base &> (other).release ());
return *this;
}
/* Converting "move" assignment. Really an lvalue ref converting
copy assignment operator that moves. See comments above. */
template<typename T1, typename D1>
unique_ptr_base &operator= (const unique_ptr_base<T1, D1> &other) throw ()
{
reset (const_cast<unique_ptr_base<T1, D1> &> (other).release ());
return *this;
}
/* std::unique_ptr does not allow assignment, except from nullptr.
nullptr doesn't exist in C++03, so we allow assignment from NULL
instead [ptr = NULL;].
*/
unique_ptr_base &operator= (detail::nullptr_t *) throw ()
{
reset ();
return *this;
}
~unique_ptr_base () { call_deleter (); }
/* "explicit operator bool ()" emulation using the safe bool
idiom. */
private:
typedef void (unique_ptr_base::*explicit_operator_bool) () const;
void this_type_does_not_support_comparisons () const {}
public:
operator explicit_operator_bool () const
{
return (m_ptr != NULL
? &unique_ptr_base::this_type_does_not_support_comparisons
: 0);
}
element_type *get () const throw () { return m_ptr; }
element_type *release () throw ()
{
pointer tmp = m_ptr;
m_ptr = NULL;
return tmp;
}
void reset (element_type *p = NULL) throw ()
{
if (p != m_ptr)
{
call_deleter ();
m_ptr = p;
}
}
private:
/* Call the deleter. Note we assume the deleter is "stateless". */
void call_deleter ()
{
D d;
d (m_ptr);
}
element_type *m_ptr;
};
} /* namespace detail */
/* Macro used to create a unique_ptr_base "partial specialization" --
a subclass that uses a specific deleter. Basically this re-defines
the necessary constructors. This is necessary because C++03
doesn't support inheriting constructors with "using". While at it,
we inherit the assignment operator. TYPE is the name of the type
being defined. Assumes that 'base_type' is a typedef of the
baseclass TYPE is inheriting from. */
#define DEFINE_GDB_UNIQUE_PTR(TYPE) \
public: \
explicit TYPE (T *p = NULL) throw () \
: base_type (p) {} \
\
TYPE (const TYPE &other) throw () : base_type (other) {} \
\
TYPE (detail::nullptr_t *) throw () : base_type (NULL) {} \
\
template<typename T1, typename D1> \
TYPE (const detail::unique_ptr_base<T1, D1> &other) throw () \
: base_type (other) {} \
\
using base_type::operator=;
/* Define single-object gdb::unique_ptr. */
template <typename T, typename D = default_delete<T> >
class unique_ptr : public detail::unique_ptr_base<T, D>
{
typedef detail::unique_ptr_base<T, D> base_type;
DEFINE_GDB_UNIQUE_PTR (unique_ptr)
public:
/* Dereferencing. */
T &operator* () const throw () { return *this->get (); }
T *operator-> () const throw () { return this->get (); }
};
/* Define gdb::unique_ptr specialization for T[]. */
template <typename T, typename D>
class unique_ptr<T[], D> : public detail::unique_ptr_base<T, D>
{
typedef detail::unique_ptr_base<T, D> base_type;
DEFINE_GDB_UNIQUE_PTR (unique_ptr)
public:
/* Indexing operator. */
T &operator[] (size_t i) const { return this->get ()[i]; }
};
/* Comparison operators. */
template <typename T, typename D,
typename U, typename E>
inline bool
operator== (const detail::unique_ptr_base<T, D> &x,
const detail::unique_ptr_base<U, E> &y)
{ return x.get() == y.get(); }
template <typename T, typename D,
typename U, typename E>
inline bool
operator!= (const detail::unique_ptr_base<T, D> &x,
const detail::unique_ptr_base<U, E> &y)
{ return x.get() != y.get(); }
template<typename T, typename D,
typename U, typename E>
inline bool
operator< (const detail::unique_ptr_base<T, D> &x,
const detail::unique_ptr_base<U, E> &y)
{ return x.get() < y.get (); }
template<typename T, typename D,
typename U, typename E>
inline bool
operator<= (const detail::unique_ptr_base<T, D> &x,
const detail::unique_ptr_base<U, E> &y)
{ return !(y < x); }
template<typename T, typename D,
typename U, typename E>
inline bool
operator> (const detail::unique_ptr_base<T, D> &x,
const detail::unique_ptr_base<U, E> &y)
{ return y < x; }
template<typename T, typename D,
typename U, typename E>
inline bool
operator>= (const detail::unique_ptr_base<T, D> &x,
const detail::unique_ptr_base<U, E> &y)
{ return !(x < y); }
/* std::move "emulation". This is as simple as it can be -- no
attempt is made to emulate rvalue references. Instead relies on
the fact that gdb::unique_ptr has move semantics like
std::auto_ptr. I.e., copy/assignment actually moves. */
template<typename T, typename D>
unique_ptr<T, D>
move (unique_ptr<T, D> v)
{
return v;
}
#endif /* C++11 */
/* Define gdb::unique_xmalloc_ptr, a gdb::unique_ptr that manages
xmalloc'ed memory. */ xmalloc'ed memory. */
/* The deleter for gdb::unique_xmalloc_ptr. Uses xfree. */ /* The deleter for std::unique_xmalloc_ptr. Uses xfree. */
template <typename T> template <typename T>
struct xfree_deleter struct xfree_deleter
{ {
void operator() (T *ptr) const { xfree (ptr); } void operator() (T *ptr) const { xfree (ptr); }
}; };
#if __cplusplus >= 201103 /* Import the standard unique_ptr to our namespace with a custom
deleter. */
/* In C++11, we just import the standard unique_ptr to our namespace
with a custom deleter. */
template<typename T> using unique_xmalloc_ptr template<typename T> using unique_xmalloc_ptr
= std::unique_ptr<T, xfree_deleter<T>>; = std::unique_ptr<T, xfree_deleter<T>>;
#else /* C++11 */
/* In C++03, we don't have template aliases, so we need to define a
subclass instead, and re-define the constructors, because C++03
doesn't support inheriting constructors either. */
template <typename T>
class unique_xmalloc_ptr : public unique_ptr<T, xfree_deleter<T> >
{
typedef unique_ptr<T, xfree_deleter<T> > base_type;
DEFINE_GDB_UNIQUE_PTR (unique_xmalloc_ptr)
};
#endif /* C++11 */
} /* namespace gdb */ } /* namespace gdb */
#endif /* GDB_UNIQUE_PTR_H */ #endif /* GDB_UNIQUE_PTR_H */