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SubjectRe: [bug report] perf jit: add source line info support
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

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