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bh=LHmiermdl6RPWlPPPWfGL90MXuUtrZGZhe9H8fs+5EQ=; b=JOMHcbEmb+OlJMpPYufI3LEI2jgOaoQxeQO43kEY68ATMFZ4BSAyWsqmGuFS+FJCzwaQ/X rZYBKu+yEbFzGsubNrMwLqNqgpxcbKJYXlu5KIqarSMAjfh0/1RwC3oSUUqd4/DXvv6LMl F78sYOTVLCXLcMFxfpc24CH65ARZ7cY= 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 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer2=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.133.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer2=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer2=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1695302628780100001 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