From: Pedro Alves <palves@redhat.com>
To: Tom Tromey <tom@tromey.com>, gdb-patches@sourceware.org
Subject: Re: [PATCH v2 09/10] Avoid undefined behavior in expression dumping
Date: Wed, 03 Oct 2018 17:48:00 -0000 [thread overview]
Message-ID: <bf1f2d52-9093-863f-ab7e-921042fd397d@redhat.com> (raw)
In-Reply-To: <20181002044420.17628-10-tom@tromey.com>
On 10/02/2018 05:44 AM, Tom Tromey wrote:
> -fsanitize=undefined pointed out undefined behavior in
> dump_raw_expression like:
>
> runtime error: load of value 2887952, which is not a valid value for type 'exp_opcode'
>
> dump_raw_expression will try to print the opcode for each element of
> the expression, even when it is not valid. To allow this, but have it
> avoid undefined behavior, this patch sets the underlying type of enum
> exp_opcode, and arranges for op_name to handle invalid opcodes more
> nicely.
>
> Before this patch, debug-expr.exp shows:
>
> Dump of expression @ 0x60f000007750, before conversion to prefix form:
> Language c, 8 elements, 16 bytes each.
> Index Opcode Hex Value String Value
> 0 OP_TYPE 89 Y...............
> <unknown 3851920> 107820862850704 ..:..b..........
> 2 OP_TYPE 89 Y...............
> 3 OP_VAR_VALUE 40 (...............
> 4 <unknown 2807568> 107820861806352 ..*..b..........
> 5 <unknown 2806368> 107820861805152 `.*..b..........
> 6 OP_VAR_VALUE 40 (...............
> 7 UNOP_MEMVAL_TYPE 57 9...............
>
> Afterward, the output is:
>
> Dump of expression @ 0x4820f90, before conversion to prefix form:
> Language c, 8 elements, 16 bytes each.
> Index Opcode Hex Value String Value
> 0 OP_TYPE 89 Y...............
> 1 unknown opcode: 176 75444400 .0..............
> 2 OP_TYPE 89 Y...............
> 3 OP_VAR_VALUE 40 (...............
> 4 OP_BOOL 74616912 P.r.............
> 5 unknown opcode: 128 74615680 ..r.............
> 6 OP_VAR_VALUE 40 (...............
> 7 UNOP_MEMVAL_TYPE 57 9...............
>
LGTM. Thanks for adding the example.
Thanks,
Pedro Alves
next prev parent reply other threads:[~2018-10-03 17:48 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-02 4:44 [PATCH v2 00/10] Undefined Behavior Sanitizer, this time with docs Tom Tromey
2018-10-02 4:44 ` [PATCH v2 05/10] Avoid undefined behavior in read_subrange_type Tom Tromey
2018-10-02 4:44 ` [PATCH v2 03/10] Use unsigned as base type for some enums Tom Tromey
2018-10-03 17:33 ` Pedro Alves
2018-10-03 21:07 ` Tom Tromey
2018-10-02 4:44 ` [PATCH v2 01/10] Do not pass NULL to memcpy Tom Tromey
2018-10-02 4:44 ` [PATCH v2 06/10] Avoid undefined behavior in parse_number Tom Tromey
2018-10-02 4:44 ` [PATCH v2 02/10] Change dwarf2_frame_state_reg_info::reg to be std::vector Tom Tromey
2018-10-03 17:28 ` Pedro Alves
2018-10-03 21:05 ` Tom Tromey
2018-10-02 4:44 ` [PATCH v2 07/10] Avoid undefined behavior in read_signed_leb128 Tom Tromey
2018-10-02 4:44 ` [PATCH v2 04/10] Avoid undefined behavior in extract_integer Tom Tromey
2018-10-02 4:44 ` [PATCH v2 09/10] Avoid undefined behavior in expression dumping Tom Tromey
2018-10-03 17:48 ` Pedro Alves [this message]
2018-10-02 4:44 ` [PATCH v2 08/10] Avoid undefined behavior in ada_operator_length Tom Tromey
2018-10-02 4:44 ` [PATCH v2 10/10] Add --enable-ubsan Tom Tromey
2018-10-02 13:53 ` Eli Zaretskii
2018-10-02 21:26 ` Tom Tromey
2018-10-02 21:28 ` Tom Tromey
2018-10-03 17:31 ` Eli Zaretskii
2018-10-03 17:54 ` Pedro Alves
2018-10-03 21:09 ` Tom Tromey
2018-10-03 17:57 ` [PATCH v2 00/10] Undefined Behavior Sanitizer, this time with docs Pedro Alves
2018-10-03 21:09 ` Tom Tromey
2018-10-08 19:14 ` John Baldwin
2018-10-08 20:22 ` Joel Brobecker
2018-10-09 10:44 ` Pedro Alves
2018-10-12 21:07 ` Joel Brobecker
-- strict thread matches above, loose matches on Subject: below --
2018-08-30 2:44 [PATCH v2 00/10] Enable undefined behavior sanitizer Tom Tromey
2018-08-30 2:44 ` [PATCH v2 09/10] Avoid undefined behavior in expression dumping Tom Tromey
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