From ef10c3ace00674e8c3599c3bf95f06c87d68898b Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Thu, 25 Jun 2015 08:16:00 -0700 Subject: Use strtab with GC and suffix merging for .strtab This patch uses ELF strtab with GC and suffix merging support to create ELF .strtab section. There is some small memory overhead to use ELF strtab: ==14928== HEAP SUMMARY: ==14928== in use at exit: 3,276,318 bytes in 679 blocks ==14928== total heap usage: 1,544 allocs, 865 frees, 15,259,146 bytes allocated vs. ==14936== HEAP SUMMARY: ==14936== in use at exit: 3,276,318 bytes in 679 blocks ==14936== total heap usage: 1,532 allocs, 853 frees, 15,026,402 bytes allocated when running: ./ld-new -m elf_x86_64 -o tmpdir/ld-partial.o -r ldgram.o ldlex-wrapper.o lexsup.o ldlang.o mri.o ldctor.o ldmain.o plugin.o ldwrite.o ldexp.o ldemul.o ldver.o ldmisc.o ldfile.o ldcref.o eelf_x86_64.o eelf32_x86_64.o eelf_i386.o eelf_iamcu.o ei386linux.o eelf_l1om.o eelf_k1om.o ldbuildid.o The results are [32] .strtab STRTAB 0+ 3beff8 00407a 00 0 0 1 vs [32] .strtab STRTAB 0+ 3beff8 0041d8 00 0 0 1 It reduces the .strtab size by 350 bytes, about 2% Saving on libc.so from glibc is much more since libc.so has many alias symbols with the same suffix. For x32 glibc, [82] .strtab STRTAB 0+ 81b348 0159e7 00 0 0 1 vs [82] .strtab STRTAB 0+ 81b8bc 019e72 00 0 0 1 It reduces the .strtab size by 17547 bytes, about 16%. bfd/ PR gas/18451 * elf-bfd.h (elf_sym_strtab): New. (elf_link_hash_table): Add strtabcount, strtabsize and strtab. (_bfd_elf_stringtab_init): Removed. * elf.c (_bfd_elf_stringtab_init): Removed. (_bfd_elf_compute_section_file_positions): Replace bfd_strtab_hash/_bfd_elf_stringtab_init/_bfd_stringtab_free/ _bfd_stringtab_size with elf_strtab_hash/_bfd_elf_strtab_init/_bfd_elf_strtab_free/ _bfd_elf_strtab_size. Use _bfd_elf_strtab_add, _bfd_elf_strtab_finalize and _bfd_elf_strtab_offset to get st_name. (swap_out_syms): Likewise. * elflink.c (elf_final_link_info): Replace bfd_strtab_hash with elf_strtab_hash. Remove symbuf, symbuf_count, symbuf_size and shndxbuf_size. (elf_link_flush_output_syms): Removed. (elf_link_output_sym): Renamed to ... (elf_link_output_symstrtab): This. Replace _bfd_stringtab_add with _bfd_elf_strtab_add. Don't flush symbols to the file nor swap out symbols. (elf_link_swap_symbols_out): New. (elf_link_output_extsym): Replace elf_link_output_sym with elf_link_output_symstrtab. (elf_link_input_bfd): Likewise. (elf_final_link_free): Replace _bfd_stringtab_free with _bfd_elf_strtab_free. Remove symbuf. (bfd_elf_final_link): Replace _bfd_elf_stringtab_init with _bfd_elf_strtab_init. Don't set symbuf, symbuf_count, symbuf_size nor shndxbuf_size. Initialize strtabsize and strtab. Initialize symshndxbuf to -1 when number of sections >= 64K. Replace elf_link_output_sym/elf_link_output_sym with elf_link_output_symstrtab/elf_link_output_symstrtab. Don't call elf_link_flush_output_syms. Call _bfd_elf_strtab_finalize and elf_link_swap_symbols_out. Replace _bfd_stringtab_size and _bfd_stringtab_emit with _bfd_elf_strtab_size and _bfd_elf_strtab_emit. gas/testsuite/ PR gas/18451 * gas/elf/elf.exp: Run strtab. * gas/elf/strtab.d: New file. * gas/elf/strtab.s: Likewise. ld/testsuite/ PR gas/18451 * ld-elf/strtab.d: New file. * ld-elf/strtab.s: Likewise. --- ld/testsuite/ChangeLog | 6 ++++++ ld/testsuite/ld-elf/strtab.d | 7 +++++++ ld/testsuite/ld-elf/strtab.s | 8 ++++++++ 3 files changed, 21 insertions(+) create mode 100644 ld/testsuite/ld-elf/strtab.d create mode 100644 ld/testsuite/ld-elf/strtab.s (limited to 'ld') diff --git a/ld/testsuite/ChangeLog b/ld/testsuite/ChangeLog index 2031bc8..abc431e 100644 --- a/ld/testsuite/ChangeLog +++ b/ld/testsuite/ChangeLog @@ -1,3 +1,9 @@ +2015-06-25 H.J. Lu + + PR gas/18451 + * ld-elf/strtab.d: New file. + * ld-elf/strtab.s: Likewise. + 2015-06-24 H.J. Lu * ld-i386/i386.exp: Run pltgot-2 for Linux targets. diff --git a/ld/testsuite/ld-elf/strtab.d b/ld/testsuite/ld-elf/strtab.d new file mode 100644 index 0000000..0797708 --- /dev/null +++ b/ld/testsuite/ld-elf/strtab.d @@ -0,0 +1,7 @@ +#ld: -shared +#readelf: -W -x .strtab + +#failif +#... + +0x[0-9 ]+.*\.xxxx\..* +#... diff --git a/ld/testsuite/ld-elf/strtab.s b/ld/testsuite/ld-elf/strtab.s new file mode 100644 index 0000000..931d9ef --- /dev/null +++ b/ld/testsuite/ld-elf/strtab.s @@ -0,0 +1,8 @@ + .text +.globl x; x: +.globl xx; xx: +.globl xxx; xxx: +.globl xxxx; xxxx: +.globl xxxxx; xxxxx: +.globl xxxxxx; xxxxxx: + .byte 0 -- cgit v1.1