From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Paul Eggert Newsgroups: gmane.emacs.bugs Subject: bug#31750: simplify and tune Emacs stack-related allocation Date: Sat, 9 Jun 2018 21:03:25 -0700 Organization: UCLA Computer Science Department Message-ID: <14685fe0-39b9-deb6-6960-0e9572c4357c@cs.ucla.edu> References: <9aeda5fe-dc7c-30d5-39df-2942410a672b@cs.ucla.edu> <87po0zz5bd.fsf@gmail.com> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Trace: blaine.gmane.org 1528604637 28616 195.159.176.226 (10 Jun 2018 04:23:57 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sun, 10 Jun 2018 04:23:57 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 Cc: 31750@debbugs.gnu.org To: Noam Postavsky Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Sun Jun 10 06:23:52 2018 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1fRrtQ-0007O6-AS for geb-bug-gnu-emacs@m.gmane.org; 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Sat, 9 Jun 2018 21:03:27 -0700 (PDT) Original-Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id YW7Q7shH5rtv; Sat, 9 Jun 2018 21:03:27 -0700 (PDT) Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 031FA1606C1; Sat, 9 Jun 2018 21:03:27 -0700 (PDT) X-Virus-Scanned: amavisd-new at zimbra.cs.ucla.edu Original-Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id brb30jefTjyx; Sat, 9 Jun 2018 21:03:26 -0700 (PDT) Original-Received: from [192.168.1.9] (unknown [47.154.30.119]) by zimbra.cs.ucla.edu (Postfix) with ESMTPSA id A751D160615; Sat, 9 Jun 2018 21:03:26 -0700 (PDT) Openpgp: preference=signencrypt Autocrypt: addr=eggert@cs.ucla.edu; prefer-encrypt=mutual; keydata= xsFNBEyAcmQBEADAAyH2xoTu7ppG5D3a8FMZEon74dCvc4+q1XA2J2tBy2pwaTqfhpxxdGA9 Jj50UJ3PD4bSUEgN8tLZ0san47l5XTAFLi2456ciSl5m8sKaHlGdt9XmAAtmXqeZVIYX/UFS 96fDzf4xhEmm/y7LbYEPQdUdxu47xA5KhTYp5bltF3WYDz1Ygd7gx07Auwp7iw7eNvnoDTAl KAl8KYDZzbDNCQGEbpY3efZIvPdeI+FWQN4W+kghy+P6au6PrIIhYraeua7XDdb2LS1en3Ss mE3QjqfRqI/A2ue8JMwsvXe/WK38Ezs6x74iTaqI3AFH6ilAhDqpMnd/msSESNFt76DiO1ZK QMr9amVPknjfPmJISqdhgB1DlEdw34sROf6V8mZw0xfqT6PKE46LcFefzs0kbg4GORf8vjG2 Sf1tk5eU8MBiyN/bZ03bKNjNYMpODDQQwuP84kYLkX2wBxxMAhBxwbDVZudzxDZJ1C2VXujC OJVxq2kljBM9ETYuUGqd75AW2LXrLw6+MuIsHFAYAgRr7+KcwDgBAfwhPBYX34nSSiHlmLC+ KaHLeCLF5ZI2vKm3HEeCTtlOg7xZEONgwzL+fdKo+D6SoC8RRxJKs8a3sVfI4t6CnrQzvJbB n6gxdgCu5i29J1QCYrCYvql2UyFPAK+do99/1jOXT4m2836j1wARAQABzSBQYXVsIEVnZ2Vy dCA8ZWdnZXJ0QGNzLnVjbGEuZWR1PsLBfgQTAQIAKAUCTIByZAIbAwUJEswDAAYLCQgHAwIG FQgCCQoLBBYCAwECH In-Reply-To: <87po0zz5bd.fsf@gmail.com> Content-Language: en-US X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 208.118.235.43 X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.org gmane.emacs.bugs:147258 Archived-At: Noam Postavsky wrote: > Paul Eggert writes: >=20 >> Subject: [PATCH 01/10] New mint_ptr representation for C pointers >> >> * src/lisp.h (make_mint_ptr, mint_ptrp, xmint_pointer): New functions. >=20 >> Use mint pointers instead of merely save pointers. >=20 > I think it would be helpful to add a brief summary of the tradeoffs > between save pointers and mint pointers to the commit message. Thanks for looking at it. Here's a quick attempt at a summary comment for= =20 make_mint_ptr. This wording compares mint_ptr values to Lisp_User_Ptr val= ues,=20 not to save pointers, in order simplify the later patch that removes save= pointers. /* A mint_ptr object OBJ represents a C-language pointer P efficiently. Preferably (and typically), OBJ is a Lisp integer I such that XINTPTR (I) =3D=3D P, as this represents P within a single Lisp value without requiring any auxiliary memory. However, if P would be damaged by being tagged as an integer and then untagged via XINTPTR, then OBJ is a Lisp_Save_Value with pointer component P. mint_ptr objects are efficiency hacks that are intended for use only within C code. C code should never blindly accept a mint_ptr object from Lisp code, as that would allow Lisp code to coin pointers from integers and could lead to crashes. A C pointer that needs to be packaged into a Lisp-visible object can be made part of a Lisp_Misc type instead; see Lisp_User_Ptr for an example. */