From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugzilla@gcc.gnu.org>
Received: by sourceware.org (Postfix, from userid 48)
	id 8973E3853573; Thu, 12 Jan 2023 21:05:16 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 8973E3853573
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1673557516;
	bh=2bJEerN7Uya6ebJetvg6TB63tBLGPOYpkgrf4+itbzM=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=htCEwN5rnMwFKzVuvIk6ei7wLJ+buX6ysEiQzaJve5AeQiIEGqg4wbkpgJFcD2Ivl
	 b85I/UgNwoJIvBb1zzdexABd6BNU0pf0FeEGeNYhUctv+/ysNek0lvWtUktxpIJNCk
	 XT3+WqQs50DfCMz7+zhueFf74Q3Ezx5Vv4EB294U=
From: "dmalcolm at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug analyzer/105273] -Wanalyzer-use-of-uninitialized-value warns on
 "missing" default for switch when callers can be statically determined
Date: Thu, 12 Jan 2023 21:05:16 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: analyzer
X-Bugzilla-Version: 12.0
X-Bugzilla-Keywords: diagnostic
X-Bugzilla-Severity: normal
X-Bugzilla-Who: dmalcolm at gcc dot gnu.org
X-Bugzilla-Status: UNCONFIRMED
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: dmalcolm at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-105273-4-uQ8m6bIwOz@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-105273-4@http.gcc.gnu.org/bugzilla/>
References: <bug-105273-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
List-Id: <gcc-bugs.sourceware.org>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D105273

--- Comment #6 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
Another instance from Doom, this time where the enum is in a field lookup,
rather than an input parameter:

p_maputl.c: In function =E2=80=98P_BoxOnLineSide=E2=80=99:
p_maputl.c:151:8: warning: use of uninitialized value =E2=80=98p1=E2=80=99 =
[CWE-457]
[-Wanalyzer-use-of-uninitialized-value]
  151 |     if (p1 =3D=3D p2)
      |        ^
  =E2=80=98P_BoxOnLineSide=E2=80=99: events 1-5
    |
    |  115 |     int         p1;
    |      |                 ^~
    |      |                 |
    |      |                 (1) region created on stack here
    |      |                 (2) capacity: 4 bytes
    |......
    |  118 |     switch (ld->slopetype)
    |      |     ~~~~~~=20=20=20=20=20=20=20
    |      |     |
    |      |     (3) following =E2=80=98default:=E2=80=99 branch...
    |......
    |  151 |     if (p1 =3D=3D p2)
    |      |        ~=20=20=20=20=20=20=20=20=20
    |      |        |
    |      |        (4) ...to here
    |      |        (5) use of uninitialized value =E2=80=98p1=E2=80=99 here
    |

where r_defs.h has:

//
// Move clipping aid for LineDefs.
//
typedef enum
{
    ST_HORIZONTAL,
    ST_VERTICAL,
    ST_POSITIVE,
    ST_NEGATIVE

} slopetype_t;

typedef struct line_s
{
    [...snip...]

    // To aid move clipping.
    slopetype_t slopetype;

    [...snip...]
} line_t;

and all four enum values are covered by the switch statement.=