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SubjectRe: [PATCH v2 03/14] perf report: create real callchain entries for inlined frames
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On Mittwoch, 16. August 2017 09:53:13 CEST Namhyung Kim wrote:
> Hi Milian,
>
> On Sun, Aug 06, 2017 at 11:24:35PM +0200, Milian Wolff wrote:
> > The inlined frames use a fake symbol that is tracked in a special
> > map inside the dso, which is always sorted by name. All other
>
> It seems the above is not true. Fake symbols are maintained by
> inline_node which in turn maintained by dso->inlines tree.

OK, I'll rephrase this to make it more explicit. But what I call "map" is what
you call "tree", no?

<snip>

> > @@ -201,7 +202,8 @@ static inline void callchain_cursor_reset(struct
> > callchain_cursor *cursor)>
> > int callchain_cursor_append(struct callchain_cursor *cursor, u64 ip,
> >
> > struct map *map, struct symbol *sym,
> > bool branch, struct branch_flags *flags,
> >
> > - int nr_loop_iter, int samples, u64 branch_from);
> > + int nr_loop_iter, int samples, u64 branch_from,
> > + const char *srcline);
> >
> > /* Close a cursor writing session. Initialize for the reader */
> > static inline void callchain_cursor_commit(struct callchain_cursor
> > *cursor)
>
> I think it'd be better splitting srcline change into a separate
> commit.

OK, I'll try to see how this goes. It would simply add the boiler plate code
to pass the srcline around, and then set it from within the callchain code,
right?

> > diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
> > index b9e087fb8247..72e6e390fd26 100644
> > --- a/tools/perf/util/dso.c
> > +++ b/tools/perf/util/dso.c
> > @@ -9,6 +9,7 @@
> >
> > #include "compress.h"
> > #include "path.h"
> > #include "symbol.h"
> >
> > +#include "srcline.h"
> >
> > #include "dso.h"
> > #include "machine.h"
> > #include "auxtrace.h"
> >
> > @@ -1233,6 +1234,7 @@ void dso__delete(struct dso *dso)
> >
> > dso->long_name);
> >
> > for (i = 0; i < MAP__NR_TYPES; ++i)
> >
> > symbols__delete(&dso->symbols[i]);
> >
> > + inlines__tree_delete(&dso->inlined_nodes);
>
> Hmm.. inline_node is released after symbol but it seems to have a
> problem. Please see below.
>
> > if (dso->short_name_allocated) {
> >
> > zfree((char **)&dso->short_name);
> >
> > diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
> > index f886141678eb..7d1e2b3c1f10 100644
> > --- a/tools/perf/util/dso.h
> > +++ b/tools/perf/util/dso.h
> > @@ -141,6 +141,7 @@ struct dso {
> >
> > struct rb_root *root; /* root of rbtree that rb_node is in
*/
> > struct rb_root symbols[MAP__NR_TYPES];
> > struct rb_root symbol_names[MAP__NR_TYPES];
> >
> > + struct rb_root inlined_nodes;
> >
> > struct {
> >
> > u64 addr;
> > struct symbol *symbol;
>
> [SNIP]
>
> > diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
> > index d4df353051af..a7f8499c8756 100644
> > --- a/tools/perf/util/machine.c
> > +++ b/tools/perf/util/machine.c
> > diff --git a/tools/perf/util/srcline.c b/tools/perf/util/srcline.c
> > index ebc88a74e67b..a1fdf035d1dd 100644
> > --- a/tools/perf/util/srcline.c
> > +++ b/tools/perf/util/srcline.c
> > @@ -33,28 +33,17 @@ static const char *dso__name(struct dso *dso)
> >
> > return dso_name;
> >
> > }
> >
> > -static int inline_list__append(char *filename, char *funcname, int
> > line_nr, - struct inline_node *node, struct dso *dso)
> > +static int inline_list__append(struct symbol *symbol, char *srcline,
> > + struct inline_node *node)
> >
> > {
> >
> > struct inline_list *ilist;
> >
> > - char *demangled;
> >
> > ilist = zalloc(sizeof(*ilist));
> > if (ilist == NULL)
> >
> > return -1;
> >
> > - ilist->filename = filename;
> > - ilist->line_nr = line_nr;
> > -
> > - if (dso != NULL) {
> > - demangled = dso__demangle_sym(dso, 0, funcname);
> > - if (demangled == NULL) {
> > - ilist->funcname = funcname;
> > - } else {
> > - ilist->funcname = demangled;
> > - free(funcname);
> > - }
> > - }
> > + ilist->symbol = symbol;
> > + ilist->srcline = srcline;
> >
> > if (callchain_param.order == ORDER_CALLEE)
> >
> > list_add_tail(&ilist->list, &node->val);
> >
> > @@ -64,6 +53,30 @@ static int inline_list__append(char *filename, char
> > *funcname, int line_nr,>
> > return 0;
> >
> > }
> >
> > +// basename version that takes a const input string
> > +static const char *gnu_basename(const char *path)
> > +{
> > + const char *base = strrchr(path, '/');
> > +
> > + return base ? base + 1 : path;
> > +}
> > +
> > +static char *srcline_from_fileline(const char *file, unsigned int line)
> > +{
> > + char *srcline;
> > +
> > + if (!file)
> > + return NULL;
> > +
> > + if (!srcline_full_filename)
> > + file = gnu_basename(file);
> > +
> > + if (asprintf(&srcline, "%s:%u", file, line) < 0)
> > + return NULL;
> > +
> > + return srcline;
> > +}
> > +
> >
> > #ifdef HAVE_LIBBFD_SUPPORT
> >
> > /*
> >
> > @@ -203,19 +216,55 @@ static void addr2line_cleanup(struct a2l_data *a2l)
> >
> > #define MAX_INLINE_NEST 1024
> >
> > +static struct symbol *new_inline_sym(struct dso *dso,
> > + struct symbol *base_sym,
> > + const char *funcname)
> > +{
> > + struct symbol *inline_sym;
> > + char *demangled = NULL;
> > +
> > + if (dso) {
> > + demangled = dso__demangle_sym(dso, 0, funcname);
> > + if (demangled)
> > + funcname = demangled;
> > + }
> > +
> > + if (strcmp(funcname, base_sym->name) == 0) {
> > + // reuse the real, existing symbol
> > + inline_sym = base_sym;
>
> So inline_node could refer the existing symbol.

Yes, that does indeed seem to be an issue. I wonder why I'm not seeing any
crashes or valgrind/ASAN reports though. I'll have to dig into this.

> > + } else {
> > + // create a fake symbol for the inline frame
> > + inline_sym = symbol__new(base_sym ? base_sym->start : 0,
> > + base_sym ? base_sym->end : 0,
> > + base_sym ? base_sym->binding : 0,
> > + funcname);
> > + if (inline_sym)
> > + inline_sym->inlined = 1;
> > + }
> > +
> > + free(demangled);
> > +
> > + return inline_sym;
> > +}
> > +
> >
> > static int inline_list__append_dso_a2l(struct dso *dso,
> >
> > - struct inline_node *node)
> > + struct inline_node *node,
> > + struct symbol *sym)
> >
> > {
> >
> > struct a2l_data *a2l = dso->a2l;
> >
> > - char *funcname = a2l->funcname ? strdup(a2l->funcname) : NULL;
> > - char *filename = a2l->filename ? strdup(a2l->filename) : NULL;
> > + struct symbol *inline_sym = new_inline_sym(dso, sym, a2l->funcname);
> > + char *srcline = NULL;
> > +
> > + if (a2l->filename)
> > + srcline = srcline_from_fileline(a2l->filename, a2l->line);
> >
> > - return inline_list__append(filename, funcname, a2l->line, node, dso);
> > + return inline_list__append(inline_sym, srcline, node);
> >
> > }
>
> [SNIP]
>
> > @@ -511,10 +563,63 @@ void inline_node__delete(struct inline_node *node)
> >
> > list_for_each_entry_safe(ilist, tmp, &node->val, list) {
> >
> > list_del_init(&ilist->list);
> >
> > - zfree(&ilist->filename);
> > - zfree(&ilist->funcname);
> > + zfree(&ilist->srcline);
> > + // only the inlined symbols are owned by the list
> > + if (ilist->symbol && ilist->symbol->inlined)
> > + symbol__delete(ilist->symbol);
>
> Existing symbols are released at this moment.

Thanks for the review, I'll try to look into these issues once I have more
time again.

Cheers

--
Milian Wolff | milian.wolff@kdab.com | Senior Software Engineer
KDAB (Deutschland) GmbH&Co KG, a KDAB Group company
Tel: +49-30-521325470
KDAB - The Qt Experts

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