From d7abcbcea5ddd40a3bf28758b62f35933c59f996 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Wed, 10 Aug 2022 10:30:46 +0200 Subject: [PATCH] gas/Dwarf: properly skip zero-size functions PR gas/29451 While out_debug_abbrev() properly skips such functions, out_debug_info() mistakenly didn't. It needs to calculate the high_pc expression ahead of time, in order to skip emitting any data for the function if the value is zero. The one case which would still leave a zero-size entry is when symbol_get_obj(symp)->size ends up evaluating to zero. I hope we can expect that to not be the case, otherwise we'd need to have a way to post-process .debug_info contents between resolving expressions and actually writing the data out to the file. Even then it wouldn't be entirely obvious in which way to alter the data. --- gas/dwarf2dbg.c | 39 ++++++++++++++++++++------------------- 1 file changed, 20 insertions(+), 19 deletions(-) diff --git a/gas/dwarf2dbg.c b/gas/dwarf2dbg.c index 868ec79ee2c..f346bd6a412 100644 --- a/gas/dwarf2dbg.c +++ b/gas/dwarf2dbg.c @@ -2882,6 +2882,7 @@ out_debug_info (segT info_seg, segT abbrev_seg, segT line_seg, segT str_seg, { const char *name; size_t len; + expressionS size = { .X_op = O_constant }; /* Skip warning constructs (see above). */ if (symbol_get_bfdsym (symp)->flags & BSF_WARNING) @@ -2895,6 +2896,18 @@ out_debug_info (segT info_seg, segT abbrev_seg, segT line_seg, segT str_seg, if (!S_IS_DEFINED (symp) || !S_IS_FUNCTION (symp)) continue; +#if defined (OBJ_ELF) /* || defined (OBJ_MAYBE_ELF) */ + size.X_add_number = S_GET_SIZE (symp); + if (size.X_add_number == 0 && IS_ELF + && symbol_get_obj (symp)->size != NULL) + { + size.X_op = O_add; + size.X_op_symbol = make_expr_symbol (symbol_get_obj (symp)->size); + } +#endif + if (size.X_op == O_constant && size.X_add_number == 0) + continue; + subseg_set (str_seg, 0); name_sym = symbol_temp_new_now_octets (); name = S_GET_NAME (symp); @@ -2920,29 +2933,17 @@ out_debug_info (segT info_seg, segT abbrev_seg, segT line_seg, segT str_seg, emit_expr (&exp, sizeof_address); /* DW_AT_high_pc */ - exp.X_op = O_constant; -#if defined (OBJ_ELF) /* || defined (OBJ_MAYBE_ELF) */ - exp.X_add_number = S_GET_SIZE (symp); - if (exp.X_add_number == 0 && IS_ELF - && symbol_get_obj (symp)->size != NULL) - { - exp.X_op = O_add; - exp.X_op_symbol = make_expr_symbol (symbol_get_obj (symp)->size); - } -#else - exp.X_add_number = 0; -#endif if (DWARF2_VERSION < 4) { - if (exp.X_op == O_constant) - exp.X_op = O_symbol; - exp.X_add_symbol = symp; - emit_expr (&exp, sizeof_address); + if (size.X_op == O_constant) + size.X_op = O_symbol; + size.X_add_symbol = symp; + emit_expr (&size, sizeof_address); } - else if (exp.X_op == O_constant) - out_uleb128 (exp.X_add_number); + else if (size.X_op == O_constant) + out_uleb128 (size.X_add_number); else - emit_leb128_expr (symbol_get_value_expression (exp.X_op_symbol), 0); + emit_leb128_expr (symbol_get_value_expression (size.X_op_symbol), 0); } /* End of children. */ -- 2.30.2