From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id 9B2DA3858D39 for ; Mon, 6 Mar 2023 11:04:07 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 9B2DA3858D39 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1678100647; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=o0lg2XCD/lQzNXYdhiugTs+hpDSsLuw7s4hyPWYDw4k=; b=SlZfDQLaNWxMOQzWoeGMD08rPxUJScNLAi/rSuk4op2+1/8NqgGs7P6PxJsb1Cy2o/Anzl dPmfTWU9cUJWvIhBmnoBjL1aBinIEEoKGYkbcRWOGGciOA+6thYmpiQfSQLxuc/ZPX225e 6+CNe2rmb5MIDkrcslq9ZMj1Zo5C+yU= Received: from mail-lf1-f70.google.com (mail-lf1-f70.google.com [209.85.167.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-520-xxrUi3zxN3erk-sRcv7aVQ-1; Mon, 06 Mar 2023 06:04:06 -0500 X-MC-Unique: xxrUi3zxN3erk-sRcv7aVQ-1 Received: by mail-lf1-f70.google.com with SMTP id j30-20020a056512029e00b004db385ddddfso2638549lfp.17 for ; Mon, 06 Mar 2023 03:04:05 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678100644; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=o0lg2XCD/lQzNXYdhiugTs+hpDSsLuw7s4hyPWYDw4k=; b=lZUO/Ycp3zWd7RgsR5l960ZssIFZ87TFrF0vnmQ7eBMV+JOl5G9eO1d76IGNkDXfY7 DlKPLY+8HApjwuPixHrGucy6HPG2ToMqYP4e5Ouo1gOro35GMDJ0wscSnX5VxOZdn0v1 Slh1QuIJx4qFNOg5uLufB9ecgD5qStElV6Nct1zcVDRpRpw8Fxs9mK9GWARLCQkR/KGW 004NzT5v2as0Ypuqjirjyfbmi2aEw2hsao9YXXcW8OrRNwSXPEUR29ib94bhu9cDhMfA eq+hcmQRcfGE2tPpg8XhMQOlce5pl03lVtLvMJs8B8Ts+v1WK2H01oJ0ho52FE4XDcwC rdmw== X-Gm-Message-State: AO0yUKVtf3l2ZJFM5gQz5EIdLFEKksk0pxOelsMMsk3jj0y6XqyEWwv2 97CQMK817SFV+G9Qv5tUUiD0c+eS8AGhMf8qyyWLuxrTHST1hSaoKmYXuaVQvJlMep4CZr/nxDW iY+K4MxXYaUvp6qCfbWWzui4O2ycwYuSa6w== X-Received: by 2002:a05:651c:483:b0:295:b1af:64ca with SMTP id s3-20020a05651c048300b00295b1af64camr3069887ljc.7.1678100644789; Mon, 06 Mar 2023 03:04:04 -0800 (PST) X-Google-Smtp-Source: AK7set/sTykkN28O4EMn0vxlMbJMkKZI/k+mKHih0nWPYuGJzdwQPLlhgIupnlGzQgqe8R1tpMDpuW7A0k8Ynv7NhTE= X-Received: by 2002:a05:651c:483:b0:295:b1af:64ca with SMTP id s3-20020a05651c048300b00295b1af64camr3069881ljc.7.1678100644486; Mon, 06 Mar 2023 03:04:04 -0800 (PST) MIME-Version: 1.0 References: <20230306101121.3CFDA13A66@imap2.suse-dmz.suse.de> In-Reply-To: From: Jonathan Wakely Date: Mon, 6 Mar 2023 11:03:53 +0000 Message-ID: Subject: Re: [PATCH] [RFC] RAII auto_mpfr and autp_mpz To: Richard Biener Cc: gcc-patches@gcc.gnu.org, Jakub Jelinek X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-12.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_NONE,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On Mon, 6 Mar 2023 at 11:01, Richard Biener wrote: > > On Mon, 6 Mar 2023, Jonathan Wakely wrote: > > > On Mon, 6 Mar 2023 at 10:11, Richard Biener wrote: > > > > > > The following adds two RAII classes, one for mpz_t and one for mpfr_t > > > making object lifetime management easier. Both formerly require > > > explicit initialization with {mpz,mpfr}_init and release with > > > {mpz,mpfr}_clear. > > > > > > I've converted two example places (where lifetime is trivial). > > > > > > I've sofar only build cc1 with the change. Any comments? > > > > > > Thanks, > > > Richard. > > > > > > * system.h (class auto_mpz): New, > > > * realmpfr.h (class auto_mpfr): Likewise. > > > * fold-const-call.cc (do_mpfr_arg1): Use auto_mpfr. > > > (do_mpfr_arg2): Likewise. > > > * tree-ssa-loop-niter.cc (bound_difference): Use auto_mpz; > > > --- > > > gcc/fold-const-call.cc | 8 ++------ > > > gcc/realmpfr.h | 15 +++++++++++++++ > > > gcc/system.h | 14 ++++++++++++++ > > > gcc/tree-ssa-loop-niter.cc | 10 +--------- > > > 4 files changed, 32 insertions(+), 15 deletions(-) > > > > > > diff --git a/gcc/fold-const-call.cc b/gcc/fold-const-call.cc > > > index 43819c1f984..fa0b287cc8a 100644 > > > --- a/gcc/fold-const-call.cc > > > +++ b/gcc/fold-const-call.cc > > > @@ -130,14 +130,12 @@ do_mpfr_arg1 (real_value *result, > > > > > > int prec = format->p; > > > mpfr_rnd_t rnd = format->round_towards_zero ? MPFR_RNDZ : MPFR_RNDN; > > > - mpfr_t m; > > > > > > - mpfr_init2 (m, prec); > > > + auto_mpfr m (prec); > > > mpfr_from_real (m, arg, MPFR_RNDN); > > > mpfr_clear_flags (); > > > bool inexact = func (m, m, rnd); > > > bool ok = do_mpfr_ckconv (result, m, inexact, format); > > > - mpfr_clear (m); > > > > > > return ok; > > > } > > > @@ -224,14 +222,12 @@ do_mpfr_arg2 (real_value *result, > > > > > > int prec = format->p; > > > mpfr_rnd_t rnd = format->round_towards_zero ? MPFR_RNDZ : MPFR_RNDN; > > > - mpfr_t m; > > > > > > - mpfr_init2 (m, prec); > > > + auto_mpfr m (prec); > > > mpfr_from_real (m, arg1, MPFR_RNDN); > > > mpfr_clear_flags (); > > > bool inexact = func (m, arg0.to_shwi (), m, rnd); > > > bool ok = do_mpfr_ckconv (result, m, inexact, format); > > > - mpfr_clear (m); > > > > > > return ok; > > > } > > > diff --git a/gcc/realmpfr.h b/gcc/realmpfr.h > > > index 5e032c05f25..2db2ecc94d4 100644 > > > --- a/gcc/realmpfr.h > > > +++ b/gcc/realmpfr.h > > > @@ -24,6 +24,21 @@ > > > #include > > > #include > > > > > > +class auto_mpfr > > > +{ > > > +public: > > > + auto_mpfr () { mpfr_init (m_mpfr); } > > > + explicit auto_mpfr (mpfr_prec_t prec) { mpfr_init2 (m_mpfr, prec); } > > > + ~auto_mpfr () { mpfr_clear (m_mpfr); } > > > + > > > + operator mpfr_t& () { return m_mpfr; } > > > > > > This implicit conversion makes the following mistake possible, if code > > is incorrectly converted to use it: > > > > auto_mpfr m (prec); > > // ... > > mpfr_clear (m); // oops! > > > > You could prevent that by adding this to the class body: > > > > friend void mpfr_clear (auto_mpfr&) = delete; > > > > This will be a better match for calls to mpfr_clear(m) than using the > > implicit conversion then calling the real function, and will give an > > error if used: > > auto.cc:20:13: error: use of deleted function 'void mpfr_clear(auto_mpfr&)' > > > > This deleted friend will not be a candidate for calls to mpfr_clear > > with an argument of any other type, only for calls with an argument of > > type auto_mpfr. > > OK, it might be OK to mpfr_clear() twice and/or mpfr_clear/mpfr_init > again. Quite possibly mpfr_init should get the same treatmen, mixing > auto_* with explicit lifetime management is bad. Ah yes, good point. > > > + > > > + auto_mpfr (const auto_mpfr &) = delete; > > > > This class has an implicit-defined assignment operator, which would > > result in a leaks and double-frees. > > You should add: > > auto_mpfr &operator=(const auto_mpfr &) = delete; > > This ensures it can't becopied by construction or assignment. > > > > The same two comments apply to auto_mpz. > > Thanks a lot, I've adjusted the patch to the one below. LGTM.