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perf probe: Fix to get declared file name from clang DWARF5

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Fix to get the declared file name even if it uses file index 0
in DWARF5, using custom die_get_decl_file() function.

Actually, the DWARF5 standard says file index 0 of the DW_AT_decl_file
is invalid(1), but there is a discussion and maybe this will be updated
[2].

Anyway, clang generates such DWARF5 file for the linux kernel. Thus it
must be handled.

Without this, 'perf probe' returns an error:

   $ ./perf probe -k $BIN_PATH/vmlinux -s $SRC_PATH -L vfs_read:10
   Debuginfo analysis failed.
     Error: Failed to show lines.

With this, it can handle the case correctly:

  $ ./perf probe -k $BIN_PATH/vmlinux -s $SRC_PATH -L vfs_read:10
  <vfs_read@$SRC_PATH/fs/read_write.c:10>

       11         ret = rw_verify_area(READ, file, pos, count);
       12         if (ret)
                           return ret;

[1] DWARF5 specification 2.14 says "The value 0 indicates that no source file has been specified.")
[2] http://wiki.dwarfstd.org/index.php?title=DWARF5_Line_Table_File_Numbers)

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/166731052936.2100653.13380621874859467731.stgit@devnote3
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Masami Hiramatsu (Google) 2022-11-01 22:48:49 +09:00 committed by Arnaldo Carvalho de Melo
parent f828929ab7
commit dc9a5d2ccd
3 changed files with 42 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

47
tools/perf/util/dwarf-aux.c
View File

@ -123,7 +123,7 @@ int cu_find_lineinfo(Dwarf_Die *cu_die, Dwarf_Addr addr,
if (die_find_realfunc(cu_die, addr, &die_mem)
&& die_entrypc(&die_mem, &faddr) == 0 &&
faddr == addr) {
*fname = dwarf_decl_file(&die_mem);
*fname = die_get_decl_file(&die_mem);
dwarf_decl_line(&die_mem, lineno);
goto out;
}
@ -486,6 +486,19 @@ static int die_get_decl_fileno(Dwarf_Die *pdie)
return -ENOENT;
}
/* Return the file name by index */
static const char *die_get_file_name(Dwarf_Die *dw_die, int idx)
{
Dwarf_Die cu_die;
Dwarf_Files *files;
if (idx < 0 || !dwarf_diecu(dw_die, &cu_die, NULL, NULL) ||
dwarf_getsrcfiles(&cu_die, &files, NULL) != 0)
return NULL;
return dwarf_filesrc(files, idx, NULL, NULL);
}
/**
* die_get_call_file - Get callsite file name of inlined function instance
* @in_die: a DIE of an inlined function instance
@ -495,18 +508,22 @@ static int die_get_decl_fileno(Dwarf_Die *pdie)
*/
const char *die_get_call_file(Dwarf_Die *in_die)
{
Dwarf_Die cu_die;
Dwarf_Files *files;
int idx;
idx = die_get_call_fileno(in_die);
if (idx < 0 || !dwarf_diecu(in_die, &cu_die, NULL, NULL) ||
dwarf_getsrcfiles(&cu_die, &files, NULL) != 0)
return NULL;
return dwarf_filesrc(files, idx, NULL, NULL);
return die_get_file_name(in_die, die_get_call_fileno(in_die));
}
/**
* die_get_decl_file - Find the declared file name of this DIE
* @dw_die: a DIE for something declared.
*
* Get declared file name of @dw_die.
* NOTE: Since some version of clang DWARF5 implementation incorrectly uses
* file index 0 for DW_AT_decl_file, die_get_decl_file() will return NULL for
* such cases. Use this function instead.
*/
const char *die_get_decl_file(Dwarf_Die *dw_die)
{
return die_get_file_name(dw_die, die_get_decl_fileno(dw_die));
}
/**
* die_find_child - Generic DIE search function in DIE tree
@ -790,7 +807,7 @@ static int __die_walk_funclines_cb(Dwarf_Die *in_die, void *data)
}
if (addr) {
fname = dwarf_decl_file(in_die);
fname = die_get_decl_file(in_die);
if (fname && dwarf_decl_line(in_die, &lineno) == 0) {
lw->retval = lw->callback(fname, lineno, addr, lw->data);
if (lw->retval != 0)
@ -818,7 +835,7 @@ static int __die_walk_funclines(Dwarf_Die *sp_die, bool recursive,
int lineno;
/* Handle function declaration line */
fname = dwarf_decl_file(sp_die);
fname = die_get_decl_file(sp_die);
if (fname && dwarf_decl_line(sp_die, &lineno) == 0 &&
die_entrypc(sp_die, &addr) == 0) {
lw.retval = callback(fname, lineno, addr, data);
@ -873,7 +890,7 @@ int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data)
if (dwarf_tag(rt_die) != DW_TAG_compile_unit) {
cu_die = dwarf_diecu(rt_die, &die_mem, NULL, NULL);
dwarf_decl_line(rt_die, &decl);
decf = dwarf_decl_file(rt_die);
decf = die_get_decl_file(rt_die);
if (!decf) {
pr_debug2("Failed to get the declared file name of %s\n",
dwarf_diename(rt_die));
@ -928,7 +945,7 @@ int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data)
dwarf_decl_line(&die_mem, &inl);
if (inl != decl ||
decf != dwarf_decl_file(&die_mem))
decf != die_get_decl_file(&die_mem))
continue;
}
}

3
tools/perf/util/dwarf-aux.h
View File

@ -50,6 +50,9 @@ int die_get_call_lineno(Dwarf_Die *in_die);
/* Get callsite file name of inlined function instance */
const char *die_get_call_file(Dwarf_Die *in_die);
/* Get declared file name of a DIE */
const char *die_get_decl_file(Dwarf_Die *dw_die);
/* Get type die */
Dwarf_Die *die_get_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem);

14
tools/perf/util/probe-finder.c
View File

@ -763,7 +763,7 @@ static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
/* Skip if declared file name does not match */
if (fsp->file) {
file = dwarf_decl_file(fn_die);
file = die_get_decl_file(fn_die);
if (!file || strcmp(fsp->file, file) != 0)
return 0;
}
@ -1071,7 +1071,7 @@ static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
return DWARF_CB_OK;
/* Check declared file */
fname = dwarf_decl_file(sp_die);
fname = die_get_decl_file(sp_die);
if (!fname) {
pr_warning("A function DIE doesn't have decl_line. Maybe broken DWARF?\n");
return DWARF_CB_OK;
@ -1151,7 +1151,7 @@ static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
return DWARF_CB_OK;
if (param->file) {
fname = dwarf_decl_file(param->sp_die);
fname = die_get_decl_file(param->sp_die);
if (!fname || strtailcmp(param->file, fname))
return DWARF_CB_OK;
}
@ -1750,7 +1750,7 @@ int debuginfo__find_probe_point(struct debuginfo *dbg, u64 addr,
goto post;
}
fname = dwarf_decl_file(&spdie);
fname = die_get_decl_file(&spdie);
if (addr == baseaddr) {
/* Function entry - Relative line number is 0 */
lineno = baseline;
@ -1787,7 +1787,7 @@ int debuginfo__find_probe_point(struct debuginfo *dbg, u64 addr,
}
}
/* Verify the lineno and baseline are in a same file */
tmp = dwarf_decl_file(&spdie);
tmp = die_get_decl_file(&spdie);
if (!tmp || (fname && strcmp(tmp, fname) != 0))
lineno = 0;
}
@ -1902,13 +1902,13 @@ static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
/* Check declared file */
if (lr->file) {
fname = dwarf_decl_file(sp_die);
fname = die_get_decl_file(sp_die);
if (!fname || strtailcmp(lr->file, fname))
return DWARF_CB_OK;
}
if (die_match_name(sp_die, lr->function) && die_is_func_def(sp_die)) {
lf->fname = dwarf_decl_file(sp_die);
lf->fname = die_get_decl_file(sp_die);
dwarf_decl_line(sp_die, &lr->offset);
pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
lf->lno_s = lr->offset + lr->start;