Messages in this thread Patch in this message | | | Subject | Re: [PATCH] Properly interpret indirect call in perf annotate. | From | Martin Liška <> | Date | Mon, 27 Aug 2018 11:06:21 +0200 |
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On 08/23/2018 04:12 PM, Arnaldo Carvalho de Melo wrote: > Em Thu, Aug 23, 2018 at 02:29:34PM +0200, Martin Liška escreveu: >> The patch changes interpretation of: >> callq *0x8(%rbx) >> >> from: >> 0.26 │ → callq *8 >> to: >> 0.26 │ → callq *0x8(%rbx) >> >> in this can an address is followed by a register, thus >> one can't parse only address. > > Please mention one or two functions where such sequence appears, so that > others can reproduce your before/after more quickly,
Sure, there's self-contained example on can compile (-O2) and test. It's following call in test function:
test: .LFB1: .cfi_startproc movq %rdi, %rax subq $8, %rsp .cfi_def_cfa_offset 16 movq %rsi, %rdi movq %rdx, %rsi call *8(%rax) <---- here cmpl $1, %eax adcl $-1, %eax addq $8, %rsp .cfi_def_cfa_offset 8 ret .cfi_endproc
Martin
> > - Arnaldo > >> Signed-off-by: Martin Liška <mliska@suse.cz> >> --- >> tools/perf/util/annotate.c | 10 ++++++++-- >> 1 file changed, 8 insertions(+), 2 deletions(-) >> >> > >> diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c >> index e4268b948e0e..e32ead4744bd 100644 >> --- a/tools/perf/util/annotate.c >> +++ b/tools/perf/util/annotate.c >> @@ -246,8 +246,14 @@ static int call__parse(struct arch *arch, struct ins_operands *ops, struct map_s >> >> indirect_call: >> tok = strchr(endptr, '*'); >> - if (tok != NULL) >> - ops->target.addr = strtoull(tok + 1, NULL, 16); >> + if (tok != NULL) { >> + endptr++; >> + >> + /* Indirect call can use a non-rip register and offset: callq *0x8(%rbx). >> + * Do not parse such instruction. */ >> + if (strstr(endptr, "(%r") == NULL) >> + ops->target.addr = strtoull(endptr, NULL, 16); >> + } >> goto find_target; >> } >> >> > typedef int (*htab_eq) (const void *, const void *);
static int eq (const void *a, const void *b) { return a - b; }
struct htab { /* Current size (in entries) of the hash table */ int size;
/* Pointer to comparison function. */ htab_eq eq_f;
/* Table itself. */ void **entries;
/* Current number of elements including also deleted elements */ int n_elements;
/* Current number of deleted elements in the table */ int n_deleted;
/* The following member is used for debugging. Its value is number of all calls of `htab_find_slot' for the hash table. */ unsigned int searches;
/* The following member is used for debugging. Its value is number of collisions fixed for time of work with the hash table. */ unsigned int collisions;
unsigned int max_size;
/* This is non-zero if we are allowed to return NULL for function calls that allocate memory. */ int return_allocation_failure; };
int __attribute__ ((noinline)) test(struct htab *t, int *a, int *b) { int r = t->eq_f (a, b); if (r) return r - 1;
return 0; }
struct htab mytable; int r;
int main(int argc, char **argv) { mytable.eq_f = &eq; for (unsigned i = 0; i < 100000000; i++) r += test (&mytable, &argc, &argc); return 0; }
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