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Thu, 21 Sep 2023 12:13:13 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.192.25]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 78A4571128D; Thu, 21 Sep 2023 12:13:13 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 6A38121E6900; Thu, 21 Sep 2023 14:13:12 +0200 (CEST) X-Outflank-Mailman: Message body and most headers restored to incoming version X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 3fdba246-5878-11ee-9b0d-b553b5be7939 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1695298398; 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: content-transfer-encoding:content-transfer-encoding; bh=LHmiermdl6RPWlPPPWfGL90MXuUtrZGZhe9H8fs+5EQ=; b=gAKSFL3MB2UnkKjWIllSMNM7yx0q00egv6wn0b8Ia/aFuMooFmO4DMfpqAppWnYXkn6D9m +RsyXGRjV496w6047PWWzVoksUbDTMgXdBgmqipSic0HAQ2l9t2tzHYgAPrbMLtNteiTh7 xrjWpyHstdZVFCIYlYYwDG48JeMtmt4= X-MC-Unique: NyX3vEfCOqSYhFypna-S0Q-1 From: Markus Armbruster To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, hreitz@redhat.com, eblake@redhat.com, vsementsov@yandex-team.ru, jsnow@redhat.com, idryomov@gmail.com, pl@kamp.de, sw@weilnetz.de, sstabellini@kernel.org, anthony.perard@citrix.com, paul@xen.org, pbonzini@redhat.com, marcandre.lureau@redhat.com, berrange@redhat.com, thuth@redhat.com, philmd@linaro.org, stefanha@redhat.com, fam@euphon.net, quintela@redhat.com, peterx@redhat.com, leobras@redhat.com, kraxel@redhat.com, qemu-block@nongnu.org, xen-devel@lists.xenproject.org, alex.bennee@linaro.org, peter.maydell@linaro.org Subject: [PATCH v3 0/7] Steps towards enabling -Wshadow=local Date: Thu, 21 Sep 2023 14:13:05 +0200 Message-ID: <20230921121312.1301864-1-armbru@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1695298426865100003 Content-Type: text/plain; charset="utf-8" Local variables shadowing other local variables or parameters make the code needlessly hard to understand. Bugs love to hide in such code. Evidence: PATCH 1. Enabling -Wshadow would prevent bugs like this one. But we'd have to clean up all the offenders first. We got a lot of them. Enabling -Wshadow=3Dlocal should be less work for almost as much gain. I took a stab at it. There's a small, exciting part, and a large, boring part. The exciting part is dark preprocessor sorcery to let us nest macro calls without shadowing: PATCH 7. The boring part is cleaning up all the other warnings. I did some [PATCH 2-6], but ran out of steam long before finishing the job. Some 160 unique warnings remain. To see them, enable -Wshadow=3Dlocal like so: diff --git a/meson.build b/meson.build index 98e68ef0b1..9fc4c7ac9d 100644 --- a/meson.build +++ b/meson.build @@ -466,6 +466,9 @@ warn_flags =3D [ '-Wno-tautological-type-limit-compare', '-Wno-psabi', '-Wno-gnu-variable-sized-type-not-at-end', + '-Wshadow=3Dlocal', + '-Wno-error=3Dshadow=3Dlocal', + '-Wno-error=3Dshadow=3Dcompatible-local', ] =20 if targetos !=3D 'darwin' You may want to drop the -Wno-error lines. v3: * PATCH 7: Comment typo [Eric], peel off a pair of parenthesis [Eric], revert accidental line breaks [Kevin] v2: * PATCH 3+6: Mollify checkpatch * PATCH 4: Redo for clearer code, R-bys dropped [Kevin] * PATCH 5: Rename tweaked [Kevin] * PATCH 6: Rename local @tran instead of the parameter [Kevin] * PATCH 7: Drop PASTE(), use glue() instead [Richard]; pass identifiers instead of __COUNTER__ for readability [Eric]; add comments Markus Armbruster (7): migration/rdma: Fix save_page method to fail on polling error migration: Clean up local variable shadowing ui: Clean up local variable shadowing block/dirty-bitmap: Clean up local variable shadowing block/vdi: Clean up local variable shadowing block: Clean up local variable shadowing qobject atomics osdep: Make a few macros more hygienic include/qapi/qmp/qobject.h | 10 ++++++++-- include/qemu/atomic.h | 17 +++++++++++----- include/qemu/compiler.h | 3 +++ include/qemu/osdep.h | 27 ++++++++++++++++++------- block.c | 9 +++++---- block/monitor/bitmap-qmp-cmds.c | 19 +++++++++--------- block/qcow2-bitmap.c | 3 +-- block/rbd.c | 2 +- block/stream.c | 1 - block/vdi.c | 7 +++---- block/vvfat.c | 35 +++++++++++++++++---------------- hw/block/xen-block.c | 6 +++--- migration/block.c | 4 ++-- migration/ram.c | 8 +++----- migration/rdma.c | 14 ++++++++----- migration/vmstate.c | 2 +- ui/gtk.c | 14 ++++++------- ui/spice-display.c | 9 +++++---- ui/vnc-palette.c | 2 -- ui/vnc.c | 12 +++++------ ui/vnc-enc-zrle.c.inc | 9 ++++----- 21 files changed, 121 insertions(+), 92 deletions(-) --=20 2.41.0