From: Tom Tromey <tom@tromey.com>
To: gdb-patches@sourceware.org
Cc: Tom Tromey <tom@tromey.com>
Subject: [PATCH v2 05/10] Avoid undefined behavior in read_subrange_type
Date: Tue, 02 Oct 2018 04:44:00 -0000 [thread overview]
Message-ID: <20181002044420.17628-6-tom@tromey.com> (raw)
In-Reply-To: <20181002044420.17628-1-tom@tromey.com>
-fsanitize=undefined pointed out an undefined shift of a negative
value in read_subrange_type. The fix is to do the work in an unsigned
type, where this is defined.
gdb/ChangeLog
2018-10-01 Tom Tromey <tom@tromey.com>
* dwarf2read.c (read_subrange_type): Make "negative_mask"
unsigned.
---
gdb/ChangeLog | 5 +++++
gdb/dwarf2read.c | 4 ++--
2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index 4a35e389e9..4013c199da 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -17709,7 +17709,7 @@ read_subrange_type (struct die_info *die, struct dwarf2_cu *cu)
int low_default_is_valid;
int high_bound_is_count = 0;
const char *name;
- LONGEST negative_mask;
+ ULONGEST negative_mask;
orig_base_type = die_type (die, cu);
/* If ORIG_BASE_TYPE is a typedef, it will not be TYPE_UNSIGNED,
@@ -17842,7 +17842,7 @@ read_subrange_type (struct die_info *die, struct dwarf2_cu *cu)
the bounds as signed, and thus sign-extend their values, when
the base type is signed. */
negative_mask =
- -((LONGEST) 1 << (TYPE_LENGTH (base_type) * TARGET_CHAR_BIT - 1));
+ -((ULONGEST) 1 << (TYPE_LENGTH (base_type) * TARGET_CHAR_BIT - 1));
if (low.kind == PROP_CONST
&& !TYPE_UNSIGNED (base_type) && (low.data.const_val & negative_mask))
low.data.const_val |= negative_mask;
--
2.17.1
next prev parent reply other threads:[~2018-10-02 4:44 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 ` Tom Tromey [this message]
2018-10-02 4:44 ` [PATCH v2 01/10] Do not pass NULL to memcpy 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 07/10] Avoid undefined behavior in read_signed_leb128 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 06/10] Avoid undefined behavior in parse_number 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
2018-10-02 4:44 ` [PATCH v2 08/10] Avoid undefined behavior in ada_operator_length 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
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 05/10] Avoid undefined behavior in read_subrange_type Tom Tromey
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