OpenE2K
/
dwarves
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

btf_encoder: Fix function generation 

Current conditions for picking up function records break BTF data on
some gcc versions.

Some function records can appear with no arguments but with declaration
tag set, so moving the 'fn->declaration' in front of other checks.

Then checking if argument names are present and finally checking ftrace
filter if it's present. If ftrace filter is not available, using the
external tag to filter out non external functions.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andriin@fb.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: bpf@vger.kernel.org
Cc: dwarves@vger.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Jiri Olsa 2020-11-14 23:38:53 +01:00 committed by Arnaldo Carvalho de Melo
parent d0cd007339
commit 8156bec8ae
1 changed files with 19 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

43
btf_encoder.c
View File

@ -165,18 +165,13 @@ static int filter_functions(struct btf_elf *btfe, struct funcs_layout *fl)
return 0;
}
static bool should_generate_function(const struct btf_elf *btfe, const char *name)
static struct elf_function *find_function(const struct btf_elf *btfe,
const char *name)
{
struct elf_function *p;
struct elf_function key = { .name = name };
p = bsearch(&key, functions, functions_cnt,
sizeof(functions[0]), functions_cmp);
if (!p || p->generated)
return false;
p->generated = true;
return true;
return bsearch(&key, functions, functions_cnt, sizeof(functions[0]),
functions_cmp);
}
static bool btf_name_char_ok(char c, bool first)
@ -613,25 +608,25 @@ int cu__encode_btf(struct cu *cu, int verbose, bool force,
const char *name;
/*
* The functions_cnt != 0 means we parsed all necessary
* kernel symbols and we are using ftrace location filter
* for functions. If it's not available keep the current
* dwarf declaration check.
* Skip functions that:
* - are marked as declarations
* - do not have full argument names
* - are not in ftrace list (if it's available)
* - are not external (in case ftrace filter is not available)
*/
if (fn->declaration)
continue;
if (!has_arg_names(cu, &fn->proto))
continue;
if (functions_cnt) {
/*
* We check following conditions:
* - argument names are defined
* - there's symbol and address defined for the function
* - function address belongs to ftrace locations
* - function is generated only once
*/
if (!has_arg_names(cu, &fn->proto))
continue;
if (!should_generate_function(btfe, function__name(fn, cu)))
struct elf_function *func;
func = find_function(btfe, function__name(fn, cu));
if (!func || func->generated)
continue;
func->generated = true;
} else {
if (fn->declaration || !fn->external)
if (!fn->external)
continue;
}