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- From e8cf73215187b0c08679d726a5cc7c019fa3ea2e Mon Sep 17 00:00:00 2001
- From: Jan Beulich <[email protected]>
- Date: Wed, 10 Aug 2022 10:34:22 +0200
- Subject: [PATCH 008/160] 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.
- (cherry picked from commit d7abcbcea5ddd40a3bf28758b62f35933c59f996)
- ---
- gas/dwarf2dbg.c | 39 ++++++++++++++++++++-------------------
- 1 file changed, 20 insertions(+), 19 deletions(-)
- --- a/gas/dwarf2dbg.c
- +++ b/gas/dwarf2dbg.c
- @@ -2882,6 +2882,7 @@ out_debug_info (segT info_seg, segT abbr
- {
- 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 abbr
- 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 abbr
- 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. */
|
