* [PATCH] IBM zSystems: Fix left-shifting negative PCRel32 values (PR gas/29152)
@ 2022-05-16 18:35 Ilya Leoshkevich
2022-05-16 20:01 ` Andreas Krebbel
0 siblings, 1 reply; 2+ messages in thread
From: Ilya Leoshkevich @ 2022-05-16 18:35 UTC (permalink / raw)
To: Andreas Krebbel; +Cc: Martin Liska, Alan Modra, binutils, Ilya Leoshkevich
s390_insert_operand ()'s val, min and max are encoded PCRel32 values
and need to be left-shifted by 1 before being shown to the user.
Left-shifting negative values is undefined behavior in C, but the
current code does not try to prevent it, causing UBSan to complain.
Fix by casting the values to their unsigned equivalents before
shifting.
---
gas/config/tc-s390.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/gas/config/tc-s390.c b/gas/config/tc-s390.c
index fb452f8a986..04a3c059c91 100644
--- a/gas/config/tc-s390.c
+++ b/gas/config/tc-s390.c
@@ -622,9 +622,9 @@ s390_insert_operand (unsigned char *insn,
if (operand->flags & S390_OPERAND_PCREL)
{
- val <<= 1;
- min <<= 1;
- max <<= 1;
+ val = (offsetT) ((addressT) val << 1);
+ min = (offsetT) ((addressT) min << 1);
+ max = (offsetT) ((addressT) max << 1);
}
if (file == (char *) NULL)
as_bad (err, (int64_t) val, (int64_t) min, (int64_t) max);
--
2.35.1
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] IBM zSystems: Fix left-shifting negative PCRel32 values (PR gas/29152)
2022-05-16 18:35 [PATCH] IBM zSystems: Fix left-shifting negative PCRel32 values (PR gas/29152) Ilya Leoshkevich
@ 2022-05-16 20:01 ` Andreas Krebbel
0 siblings, 0 replies; 2+ messages in thread
From: Andreas Krebbel @ 2022-05-16 20:01 UTC (permalink / raw)
To: Ilya Leoshkevich; +Cc: Martin Liska, Alan Modra, binutils
On 5/16/22 20:35, Ilya Leoshkevich wrote:
> s390_insert_operand ()'s val, min and max are encoded PCRel32 values
> and need to be left-shifted by 1 before being shown to the user.
> Left-shifting negative values is undefined behavior in C, but the
> current code does not try to prevent it, causing UBSan to complain.
>
> Fix by casting the values to their unsigned equivalents before
> shifting.
> ---
> gas/config/tc-s390.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/gas/config/tc-s390.c b/gas/config/tc-s390.c
> index fb452f8a986..04a3c059c91 100644
> --- a/gas/config/tc-s390.c
> +++ b/gas/config/tc-s390.c
> @@ -622,9 +622,9 @@ s390_insert_operand (unsigned char *insn,
>
> if (operand->flags & S390_OPERAND_PCREL)
> {
> - val <<= 1;
> - min <<= 1;
> - max <<= 1;
> + val = (offsetT) ((addressT) val << 1);
> + min = (offsetT) ((addressT) min << 1);
> + max = (offsetT) ((addressT) max << 1);
> }
> if (file == (char *) NULL)
> as_bad (err, (int64_t) val, (int64_t) min, (int64_t) max);
Committed to master. Thanks!
Andreas
^ permalink raw reply [flat|nested] 2+ messages in thread
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