commit 49fced1206db40c71208c201165d65f92c69cebe Author: Mark Wielaard Date: Sun Mar 5 23:37:54 2017 +0100 gas: Emit name, comp_dir and producer strings in .debug_str. Putting the name, comp_dir and producer strings in the .debug_str section makes it possible to share them across CUs. This saves a small amount of space (about ~20K on a glibc libc.so.6 build with debuginfo). And makes it easier for tools like rpm debugedit to adjust the source paths when generating separate debuginfo files. gas/ * dwarf2dbg.c (out_debug_abbrev): Use DW_FORM_strp instead of DW_FORM_string for DW_AT_name, DW_AT_comp_dir and DW_AT_producer. (out_debug_info): Accept symbols to name, comp_dir and producer in the .debug_str section and emit those offsets not full strings. (out_debug_str): New function that outputs the strings for name, comp_dir and producer in .debug_str and generates symbols to those strings. (out_debug_line): Create a .debug_str section if necessary and call out_debug_str before calling out_debug_info. * testsuite/gas/aarch64/dwarf.d: Add extra section symbol to expected output. diff --git a/gas/dwarf2dbg.c b/gas/dwarf2dbg.c index 4bb658b..e02b6e8 100644 --- a/gas/dwarf2dbg.c +++ b/gas/dwarf2dbg.c @@ -1726,9 +1726,9 @@ out_debug_abbrev (segT abbrev_seg, else out_abbrev (DW_AT_ranges, DW_FORM_data8); } - out_abbrev (DW_AT_name, DW_FORM_string); - out_abbrev (DW_AT_comp_dir, DW_FORM_string); - out_abbrev (DW_AT_producer, DW_FORM_string); + out_abbrev (DW_AT_name, DW_FORM_strp); + out_abbrev (DW_AT_comp_dir, DW_FORM_strp); + out_abbrev (DW_AT_producer, DW_FORM_strp); out_abbrev (DW_AT_language, DW_FORM_data2); out_abbrev (0, 0); @@ -1739,15 +1739,11 @@ out_debug_abbrev (segT abbrev_seg, /* Emit a description of this compilation unit for .debug_info. */ static void -out_debug_info (segT info_seg, segT abbrev_seg, segT line_seg, segT ranges_seg) +out_debug_info (segT info_seg, segT abbrev_seg, segT line_seg, segT ranges_seg, + symbolS *name_sym, symbolS *comp_dir_sym, symbolS *producer_sym) { - char producer[128]; - const char *comp_dir; - const char *dirname; expressionS exp; symbolS *info_end; - char *p; - int len; int sizeof_offset; sizeof_offset = out_header (info_seg, &exp); @@ -1798,10 +1794,38 @@ out_debug_info (segT info_seg, segT abbrev_seg, segT line_seg, segT ranges_seg) TC_DWARF2_EMIT_OFFSET (section_symbol (ranges_seg), sizeof_offset); } + /* DW_AT_name, DW_AT_comp_dir and DW_AT_producer. Symbols in .debug_str + setup in out_debug_str below. */ + TC_DWARF2_EMIT_OFFSET (name_sym, sizeof_offset); + TC_DWARF2_EMIT_OFFSET (comp_dir_sym, sizeof_offset); + TC_DWARF2_EMIT_OFFSET (producer_sym, sizeof_offset); + + /* DW_AT_language. Yes, this is probably not really MIPS, but the + dwarf2 draft has no standard code for assembler. */ + out_two (DW_LANG_Mips_Assembler); + + symbol_set_value_now (info_end); +} + +/* Emit the three debug strings needed in .debug_str and setup symbols + to them for use in out_debug_info. */ +static void +out_debug_str (segT str_seg, symbolS **name_sym, symbolS **comp_dir_sym, + symbolS **producer_sym) +{ + char producer[128]; + const char *comp_dir; + const char *dirname; + char *p; + int len; + + subseg_set (str_seg, 0); + /* DW_AT_name. We don't have the actual file name that was present on the command line, so assume files[1] is the main input file. We're not supposed to get called unless at least one line number entry was emitted, so this should always be defined. */ + *name_sym = symbol_temp_new_now (); if (files_in_use == 0) abort (); if (files[1].dir) @@ -1823,22 +1847,18 @@ out_debug_info (segT info_seg, segT abbrev_seg, segT line_seg, segT ranges_seg) memcpy (p, files[1].filename, len); /* DW_AT_comp_dir */ + *comp_dir_sym = symbol_temp_new_now (); comp_dir = remap_debug_filename (getpwd ()); len = strlen (comp_dir) + 1; p = frag_more (len); memcpy (p, comp_dir, len); /* DW_AT_producer */ + *producer_sym = symbol_temp_new_now (); sprintf (producer, "GNU AS %s", VERSION); len = strlen (producer) + 1; p = frag_more (len); memcpy (p, producer, len); - - /* DW_AT_language. Yes, this is probably not really MIPS, but the - dwarf2 draft has no standard code for assembler. */ - out_two (DW_LANG_Mips_Assembler); - - symbol_set_value_now (info_end); } void @@ -1907,19 +1927,22 @@ dwarf2_finish (void) out_debug_line (line_seg); /* If this is assembler generated line info, and there is no - debug_info already, we need .debug_info and .debug_abbrev - sections as well. */ + debug_info already, we need .debug_info, .debug_abbrev and + .debug_str sections as well. */ if (emit_other_sections) { segT abbrev_seg; segT aranges_seg; segT ranges_seg; + segT str_seg; + symbolS *name_sym, *comp_dir_sym, *producer_sym; gas_assert (all_segs); info_seg = subseg_new (".debug_info", 0); abbrev_seg = subseg_new (".debug_abbrev", 0); aranges_seg = subseg_new (".debug_aranges", 0); + str_seg = subseg_new (".debug_str", 0); bfd_set_section_flags (stdoutput, info_seg, SEC_READONLY | SEC_DEBUGGING); @@ -1927,6 +1950,10 @@ dwarf2_finish (void) SEC_READONLY | SEC_DEBUGGING); bfd_set_section_flags (stdoutput, aranges_seg, SEC_READONLY | SEC_DEBUGGING); + bfd_set_section_flags (stdoutput, str_seg, + (SEC_READONLY | SEC_DEBUGGING + | SEC_MERGE | SEC_STRINGS)); + str_seg->entsize = 1; record_alignment (aranges_seg, ffs (2 * sizeof_address) - 1); @@ -1943,6 +1970,8 @@ dwarf2_finish (void) out_debug_aranges (aranges_seg, info_seg); out_debug_abbrev (abbrev_seg, info_seg, line_seg); - out_debug_info (info_seg, abbrev_seg, line_seg, ranges_seg); + out_debug_str (str_seg, &name_sym, &comp_dir_sym, &producer_sym); + out_debug_info (info_seg, abbrev_seg, line_seg, ranges_seg, + name_sym, comp_dir_sym, producer_sym); } } diff --git a/gas/testsuite/gas/aarch64/dwarf.d b/gas/testsuite/gas/aarch64/dwarf.d index 005f1d5..2a75e0b 100644 --- a/gas/testsuite/gas/aarch64/dwarf.d +++ b/gas/testsuite/gas/aarch64/dwarf.d @@ -1,7 +1,7 @@ #readelf: -s --debug-dump=aranges #as: -g -Symbol table '.symtab' contains 10 entries: +Symbol table '.symtab' contains 11 entries: Num:[ ]+Value[ ]+Size[ ]+Type[ ]+Bind[ ]+Vis[ ]+Ndx[ ]+Name 0: 0+ 0 NOTYPE LOCAL DEFAULT UND[ ]+ 1: 0+ 0 SECTION LOCAL DEFAULT 1[ ]+ @@ -11,8 +11,9 @@ Symbol table '.symtab' contains 10 entries: 5: 0+ 0 SECTION LOCAL DEFAULT 6[ ]+ 6: 0+ 0 SECTION LOCAL DEFAULT 8[ ]+ 7: 0+ 0 SECTION LOCAL DEFAULT 4[ ]+ - 8: 0+ 0 SECTION LOCAL DEFAULT 9[ ]+ - 9: 0+ 8 FUNC GLOBAL DEFAULT 1 testfunc + 8: 0+ 0 SECTION LOCAL DEFAULT 11[ ]+ + 9: 0+ 0 SECTION LOCAL DEFAULT 9[ ]+ + 10: 0+ 8 FUNC GLOBAL DEFAULT 1 testfunc Contents of the .debug_aranges section: Length: (44|28)