[PATCH 05/13] allow constructing a auto_vec with a preallocation, and a possibly larger actual allocation size
Richard Biener
richard.guenther@gmail.com
Thu May 11 08:18:00 GMT 2017
On Thu, May 11, 2017 at 9:45 AM, Trevor Saunders <tbsaunde@tbsaunde.org> wrote:
> On Wed, May 10, 2017 at 07:54:13AM +0100, Richard Sandiford wrote:
>> tbsaunde+gcc@tbsaunde.org writes:
>> > From: Trevor Saunders <tbsaunde+gcc@tbsaunde.org>
>> >
>> > This allows us to set the capacity of the vector when we construct it,
>> > and still use a stack buffer when the size is small enough.
>> >
>> > gcc/ChangeLog:
>> >
>> > 2017-05-09 Trevor Saunders <tbsaunde+gcc@tbsaunde.org>
>> >
>> > * genrecog.c (int_set::int_set): Explicitly construct our
>> > auto_vec base class.
>> > * vec.h (auto_vec::auto_vec): New constructor.
>> > ---
>> > gcc/genrecog.c | 8 +++++---
>> > gcc/vec.h | 12 ++++++++++++
>> > 2 files changed, 17 insertions(+), 3 deletions(-)
>> >
>> > diff --git a/gcc/genrecog.c b/gcc/genrecog.c
>> > index 6a9e610e7a0..b69043f0d02 100644
>> > --- a/gcc/genrecog.c
>> > +++ b/gcc/genrecog.c
>> > @@ -1407,14 +1407,16 @@ struct int_set : public auto_vec <uint64_t, 1>
>> > iterator end ();
>> > };
>> >
>> > -int_set::int_set () {}
>> > +int_set::int_set () : auto_vec<uint64_t, 1> () {}
>> >
>> > -int_set::int_set (uint64_t label)
>> > +int_set::int_set (uint64_t label) :
>> > + auto_vec<uint64_t, 1> ()
>> > {
>> > safe_push (label);
>> > }
>> >
>> > -int_set::int_set (const int_set &other)
>> > +int_set::int_set (const int_set &other) :
>> > + auto_vec<uint64_t, 1> ()
>> > {
>> > safe_splice (other);
>> > }
>>
>> Is this part of the patch necessary? Won't the default constructor
>> be used anyway?
>
> Well, without the change to the copy constructor we get this bootstrap
> warning.
>
> /src/gcc/gcc/genrecog.c: In copy constructor ‘int_set::int_set(const int_set&)’:
> /src/gcc/gcc/genrecog.c:1417:1: error: base class ‘class auto_vec<long
> unsigned int, 1>’ should be explicitly initialized in the copy
> constructor [-Werror=extra]
> int_set::int_set (const int_set &other)
> ^~~~~~~
>
>>
> So we need to do something about that. I'm not sure the other cases are
> necessary, but I was there, and being explicit seemed better than
> leaving it implicit.
Ah,
/* If these initializations are taking place in a copy constructor,
the base class should probably be explicitly initialized if there
is a user-defined constructor in the base class (other than the
default constructor, which will be called anyway). */
if (extra_warnings
&& DECL_COPY_CONSTRUCTOR_P (current_function_decl)
&& type_has_user_nondefault_constructor (BINFO_TYPE (subobject)))
warning_at (DECL_SOURCE_LOCATION (current_function_decl),
OPT_Wextra, "base class %q#T should be explicitly "
"initialized in the copy constructor",
BINFO_TYPE (subobject));
ok - fine then. Probably could be avoided with
auto_vec() = defaulted;
(or how you'd write that)
Thanks,
Richard.
> Thanks
>
> Trev
>
>> Thanks,
>> Richard
>>
>> > diff --git a/gcc/vec.h b/gcc/vec.h
>> > index fee46164b01..914f89c350c 100644
>> > --- a/gcc/vec.h
>> > +++ b/gcc/vec.h
>> > @@ -1272,6 +1272,18 @@ public:
>> > this->m_vec = &m_auto;
>> > }
>> >
>> > + auto_vec (size_t s)
>> > + {
>> > + if (s > N)
>> > + {
>> > + this->create (s);
>> > + return;
>> > + }
>> > +
>> > + m_auto.embedded_init (MAX (N, 2), 0, 1);
>> > + this->m_vec = &m_auto;
>> > + }
>> > +
>> > ~auto_vec ()
>> > {
>> > this->release ();
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