Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1533512 > unrolled thread
| Started by | Dan Carpenter <dan.carpenter@oracle.com> |
|---|---|
| First post | 2016-11-30 20:00 +0100 |
| Last post | 2016-12-10 06:30 +0100 |
| Articles | 3 — 2 participants |
Back to article view | Back to linux.kernel
[bug report] perf jit: add source line info support Dan Carpenter <dan.carpenter@oracle.com> - 2016-11-30 20:00 +0100
Re: [bug report] perf jit: add source line info support Stephane Eranian <eranian@google.com> - 2016-12-10 06:20 +0100
Re: [bug report] perf jit: add source line info support Stephane Eranian <eranian@google.com> - 2016-12-10 06:30 +0100
| From | Dan Carpenter <dan.carpenter@oracle.com> |
|---|---|
| Date | 2016-11-30 20:00 +0100 |
| Subject | [bug report] perf jit: add source line info support |
| Message-ID | <sJigO-1kn-19@gated-at.bofh.it> |
Hello Stephane Eranian,
The patch 598b7c6919c7: "perf jit: add source line info support" from
Nov 30, 2015, leads to the following static checker warning:
./tools/perf/util/genelf_debug.c:211 emit_signed_LEB128()
warn: potential left shift more than type allows '57'
./tools/perf/util/genelf_debug.c
202 static void emit_signed_LEB128(struct buffer_ext *be, long data)
203 {
204 int more = 1;
205 int negative = data < 0;
206 int size = sizeof(long) * CHAR_BIT;
207 while (more) {
208 ubyte cur = data & 0x7F;
209 data >>= 7;
210 if (negative)
211 data |= - (1 << (size - 7));
^^^^^^^^^^^^^^^^^^^^^^^^^^^
This is a no-op on 64 bit systems. I suspect it's not intentional?
212 if ((data == 0 && !(cur & 0x40)) ||
213 (data == -1l && (cur & 0x40)))
214 more = 0;
215 else
216 cur |= 0x80;
217 buffer_ext_add(be, &cur, 1);
218 }
219 }
regards,
dan carpenter
[toc] | [next] | [standalone]
| From | Stephane Eranian <eranian@google.com> |
|---|---|
| Date | 2016-12-10 06:20 +0100 |
| Message-ID | <sMIeK-4rs-5@gated-at.bofh.it> |
| In reply to | #1533512 |
Hi Dan,
On Wed, Nov 30, 2016 at 10:48 AM, Dan Carpenter
<dan.carpenter@oracle.com> wrote:
> Hello Stephane Eranian,
>
> The patch 598b7c6919c7: "perf jit: add source line info support" from
> Nov 30, 2015, leads to the following static checker warning:
>
> ./tools/perf/util/genelf_debug.c:211 emit_signed_LEB128()
> warn: potential left shift more than type allows '57'
>
> ./tools/perf/util/genelf_debug.c
> 202 static void emit_signed_LEB128(struct buffer_ext *be, long data)
> 203 {
> 204 int more = 1;
> 205 int negative = data < 0;
> 206 int size = sizeof(long) * CHAR_BIT;
> 207 while (more) {
> 208 ubyte cur = data & 0x7F;
> 209 data >>= 7;
> 210 if (negative)
> 211 data |= - (1 << (size - 7));
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^
> This is a no-op on 64 bit systems. I suspect it's not intentional?
>
I suspect size should be: size = sizeof(int) * CHAR_BIT;
I will test that.
> 212 if ((data == 0 && !(cur & 0x40)) ||
> 213 (data == -1l && (cur & 0x40)))
> 214 more = 0;
> 215 else
> 216 cur |= 0x80;
> 217 buffer_ext_add(be, &cur, 1);
> 218 }
> 219 }
>
> regards,
> dan carpenter
[toc] | [prev] | [next] | [standalone]
| From | Stephane Eranian <eranian@google.com> |
|---|---|
| Date | 2016-12-10 06:30 +0100 |
| Message-ID | <sMIoq-4xC-21@gated-at.bofh.it> |
| In reply to | #1539773 |
On Fri, Dec 9, 2016 at 9:16 PM, Stephane Eranian <eranian@google.com> wrote:
> Hi Dan,
>
> On Wed, Nov 30, 2016 at 10:48 AM, Dan Carpenter
> <dan.carpenter@oracle.com> wrote:
>> Hello Stephane Eranian,
>>
>> The patch 598b7c6919c7: "perf jit: add source line info support" from
>> Nov 30, 2015, leads to the following static checker warning:
>>
>> ./tools/perf/util/genelf_debug.c:211 emit_signed_LEB128()
>> warn: potential left shift more than type allows '57'
>>
>> ./tools/perf/util/genelf_debug.c
>> 202 static void emit_signed_LEB128(struct buffer_ext *be, long data)
>> 203 {
>> 204 int more = 1;
>> 205 int negative = data < 0;
>> 206 int size = sizeof(long) * CHAR_BIT;
>> 207 while (more) {
>> 208 ubyte cur = data & 0x7F;
>> 209 data >>= 7;
>> 210 if (negative)
>> 211 data |= - (1 << (size - 7));
>> ^^^^^^^^^^^^^^^^^^^^^^^^^^^
>> This is a no-op on 64 bit systems. I suspect it's not intentional?
>>
> I suspect size should be: size = sizeof(int) * CHAR_BIT;
> I will test that.
Sorry, I think the issue is on the 1 shift, should be 1UL instead.
>
>> 212 if ((data == 0 && !(cur & 0x40)) ||
>> 213 (data == -1l && (cur & 0x40)))
>> 214 more = 0;
>> 215 else
>> 216 cur |= 0x80;
>> 217 buffer_ext_add(be, &cur, 1);
>> 218 }
>> 219 }
>>
>> regards,
>> dan carpenter
[toc] | [prev] | [standalone]
Back to top | Article view | linux.kernel
csiph-web