From: Masami Hiramatsu (Google) Date: Tue, 1 Nov 2022 13:48:49 +0000 (+0900) Subject: perf probe: Fix to get declared file name from clang DWARF5 X-Git-Tag: v6.6.7~3878^2~184 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=dc9a5d2ccd5c823cc05cafe75fcf19b682d8152c;p=platform%2Fkernel%2Flinux-starfive.git perf probe: Fix to get declared file name from clang DWARF5 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 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 Acked-by: Namhyung Kim Cc: Alexander Shishkin Cc: Ingo Molnar Cc: Jiri Olsa Cc: Mark Rutland Cc: Peter Zijlstra Cc: Steven Rostedt (VMware) Link: https://lore.kernel.org/r/166731052936.2100653.13380621874859467731.stgit@devnote3 Signed-off-by: Arnaldo Carvalho de Melo --- diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c index 216fc3d..30b36b5 100644 --- a/tools/perf/util/dwarf-aux.c +++ b/tools/perf/util/dwarf-aux.c @@ -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; } } diff --git a/tools/perf/util/dwarf-aux.h b/tools/perf/util/dwarf-aux.h index 7ee0fa1..7ec8bc1 100644 --- a/tools/perf/util/dwarf-aux.h +++ b/tools/perf/util/dwarf-aux.h @@ -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); diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c index 1aa8fcc..54b49ce 100644 --- a/tools/perf/util/probe-finder.c +++ b/tools/perf/util/probe-finder.c @@ -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;