Re: How create small binaries with GNU binutils.
[2019-02-13 13:17] Nick Clifton > [1]. You could check this theory by running "readelf --section-headers > --program-headers" > on the two binaries. Both should have program headers but, if the > theory is right, only the ld generated binary will have section headers. Checked. Confirmed. > [...] > I am sorry, but I think that I going to be unable to help you. :-( Understood. Thank you for your help. I need to read more about ELF format. -- Note, that I send and fetch email in batch, once every 24 hours. If matter is urgent, try https://t.me/kaction -- ___ bug-binutils mailing list bug-binutils@gnu.org https://lists.gnu.org/mailman/listinfo/bug-binutils
Re: How create small binaries with GNU binutils.
Hi Dmitry, > Thank you for suggestion, but map did not reveal anything. The only part > (section?) with non zero size is .text of size 0xd (=13). This is > correct, raw instructions are really 13 bytes (according to `objdump -d'). > By the way, `readelf --sections' reports, that there is no sections in > fasm-generated binary. I do not know, how does fasm do it, but probably > is saves on section headers or something like this. Is is possible to > make `ld' do the same? Ah ha - maybe that is it. Maybe fasm is generating a binary with just program segments but no sections, whereas ld is generating a binary with both sections and segments[1]. Unfortunately I do not know of a way to tell ld to stop generating the sections. Unfortunately it also appears that the objcopy tool does not have an option for removing the sections either. (Actually it does, but removing the sections would remove the code as well, whereas what we want to do is to remove the section header table but leave in the program header table). I am sorry, but I think that I going to be unable to help you. :-( Cheers Nick [1]. You could check this theory by running "readelf --section-headers --program-headers" on the two binaries. Both should have program headers but, if the theory is right, only the ld generated binary will have section headers. ___ bug-binutils mailing list bug-binutils@gnu.org https://lists.gnu.org/mailman/listinfo/bug-binutils
Re: How create small binaries with GNU binutils.
[2019-02-07 15:43] Nick Clifton
>
> part text/plain 498
> Hi Dmitry,
>
> >>> Still, even this way, 400 bytes is more then twice as big, compared to
> >>> fasm. Any suggestions, how to shrink binary futher?
>
> > Thank you for suggestion. Tried both options; no difference -- 400
> > bytes.
>
> Ho Hum. In which case, do you know what is in the extra bytes ? If you
> link with the -Map=foo.map option you should get a map file which shows
> you how the output was constructed. Perhaps this can help you find out
> where the extra bytes are coming from.
Thank you for suggestion, but map did not reveal anything. The only part
(section?) with non zero size is .text of size 0xd (=13). This is
correct, raw instructions are really 13 bytes (according to `objdump -d').
According to `readelf --sections', there is only `.text' and `.shstrtab'
sections.
By the way, `readelf --sections' reports, that there is no sections in
fasm-generated binary. I do not know, how does fasm do it, but probably
is saves on section headers or something like this. Is is possible to
make `ld' do the same?
Also, there is PAX_HEADERS header in binutils-generated binary.
Here is map, maybe you could extract more of it:
Memory Configuration
Name Origin Length Attributes
*default*0x 0x
Linker script and memory map
LOAD a01.o
[!provide]PROVIDE (__executable_start
= SEGMENT_START ("text-segment", 0x40))
0x004000b0. = (SEGMENT_START
("text-segment", 0x40) + SIZEOF_HEADERS)
.interp
*(.interp)
.note.gnu.build-id
*(.note.gnu.build-id)
.hash
*(.hash)
.gnu.hash
*(.gnu.hash)
.dynsym
*(.dynsym)
.dynstr
*(.dynstr)
.gnu.version
*(.gnu.version)
.gnu.version_d
*(.gnu.version_d)
.gnu.version_r
*(.gnu.version_r)
.rela.dyn 0x004000b00x0
*(.rela.init)
*(.rela.text .rela.text.* .rela.gnu.linkonce.t.*)
*(.rela.fini)
*(.rela.rodata .rela.rodata.* .rela.gnu.linkonce.r.*)
*(.rela.data .rela.data.* .rela.gnu.linkonce.d.*)
*(.rela.tdata .rela.tdata.* .rela.gnu.linkonce.td.*)
*(.rela.tbss .rela.tbss.* .rela.gnu.linkonce.tb.*)
*(.rela.ctors)
*(.rela.dtors)
*(.rela.got)
.rela.got 0x004000b00x0 a01.o
*(.rela.bss .rela.bss.* .rela.gnu.linkonce.b.*)
*(.rela.ldata .rela.ldata.* .rela.gnu.linkonce.l.*)
*(.rela.lbss .rela.lbss.* .rela.gnu.linkonce.lb.*)
*(.rela.lrodata .rela.lrodata.* .rela.gnu.linkonce.lr.*)
*(.rela.ifunc)
.rela.plt 0x004000b00x0
*(.rela.plt)
[!provide]PROVIDE (__rela_iplt_start
= .)
*(.rela.iplt)
.rela.iplt 0x004000b00x0 a01.o
[!provide]PROVIDE (__rela_iplt_end =
.)
.init
*(SORT_NONE(.init))
.plt0x004000b00x0
*(.plt)
*(.iplt)
.iplt 0x004000b00x0 a01.o
.plt.got
*(.plt.got)
.plt.sec
*(.plt.sec)
.text 0x004000b00xd
*(.text.unlikely .text.*_unlikely .text.unlikely.*)
*(.text.exit .text.exit.*)
*(.text.startup .text.startup.*)
*(.text.hot .text.hot.*)
*(.text .stub .text.* .gnu.linkonce.t.*)
.text 0x004000b00xd a01.o
0x004000b0_start
*(.gnu.warning)
.fini
*(SORT_NONE(.fini))
[!provide]PROVIDE (__etext = .)
[!provide]PROVIDE (_etext = .)
[!provide]PROVIDE (etext = .)
.rodata
*(.rodata .rodata.* .gnu.linkonce.r.*)
.rodata1
*(.rodata1)
.eh_frame_hdr
*(.eh_frame_hdr)
*(.eh_frame_entry .eh_frame_entry.*)
.eh_frame
*(.eh_frame)
*(.eh_frame.*)
.gcc_except_table
*(.gcc_except_table .gcc_except_table.*)
.gnu_extab
*(.gnu_extab*)
.exception_ranges
*(.exception_ranges .exception_ranges*)
0x006000bd. = DATA_SEGMENT_ALIGN
(CONSTANT (MAXPAGESIZE), CONSTANT (COMMONPAGESIZE))
.eh_frame
*(.eh_frame)
*(.eh_frame.*)
.gnu_extab
*(.gnu_extab)
.gcc_except_table
*(.gcc_except_table .gcc_except_table.*)
.exception_ranges
*(.exception_ranges .exception_ranges*)
.tdata
*(.tdata .tdata.* .gnu.linkonce.td.*)
.tbss
*(.tbss .tbss.* .gnu.linkonce.tb.*)
*(.tcommon)
.preinit_array 0x006000bd0x0
[!provide]PROVIDE
(__preinit_array_start = .)
*(.preinit_array)
[!provide]PROVIDE
(__preinit_array_end = .)
.init_array 0x006000bd0x0
[!provide]PROVIDE (__init_array_start
= .)
*(SO
Re: How create small binaries with GNU binutils.
Hi Dmitry, >>> Still, even this way, 400 bytes is more then twice as big, compared to >>> fasm. Any suggestions, how to shrink binary futher? > Thank you for suggestion. Tried both options; no difference -- 400 > bytes. Ho Hum. In which case, do you know what is in the extra bytes ? If you link with the -Map=foo.map option you should get a map file which shows you how the output was constructed. Perhaps this can help you find out where the extra bytes are coming from. Cheers Nick ___ bug-binutils mailing list bug-binutils@gnu.org https://lists.gnu.org/mailman/listinfo/bug-binutils
Re: How create small binaries with GNU binutils.
[2019-02-04 09:50] Nick Clifton > > Still, even this way, 400 bytes is more then twice as big, compared to > > fasm. Any suggestions, how to shrink binary futher? > > This might be because the linker defaults to page aligning the binaries. > Have you tried linking with the --nmagic option ? (Or alternatively the > --omagic option). Thank you for suggestion. Tried both options; no difference -- 400 bytes. -- Note, that I send and fetch email in batch, once every 24 hours. If matter is urgent, try https://t.me/kaction -- ___ bug-binutils mailing list bug-binutils@gnu.org https://lists.gnu.org/mailman/listinfo/bug-binutils
Re: How create small binaries with GNU binutils.
Hi Dmitry, > Still, even this way, 400 bytes is more then twice as big, compared to > fasm. Any suggestions, how to shrink binary futher? This might be because the linker defaults to page aligning the binaries. Have you tried linking with the --nmagic option ? (Or alternatively the --omagic option). Cheers Nick ___ bug-binutils mailing list bug-binutils@gnu.org https://lists.gnu.org/mailman/listinfo/bug-binutils
Re: How create small binaries with GNU binutils.
[2019-02-01 17:49] Andreas Schwab > On Feb 01 2019, Dmitry Bogatov wrote: > > > results in huge binary: > > > > $ du -hb a.out > > 4744a.out > > $ strip -s a.out > > $ du -hb a.out > > 4408a.out > > $ file a.out > > a.out: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), statically > > linked, stripped > > I cannot reproduce that. > > $ stat -c %s a.out > 664 > $ strip a.out > $ stat -c %s a.out > 344 > $ size a.out >textdata bss dec hex filename > 13 0 0 13 d a.out > $ rpm -q binutils > binutils-2.31.90-lp150.5.68.1.x86_64 Interesting. I tried bintuils, packaged by Nix, and resulted (after strip -s) exactly 400 bytes. I will report debian packaging. Still, even this way, 400 bytes is more then twice as big, compared to fasm. Any suggestions, how to shrink binary futher? -- Note, that I send and fetch email in batch, once every 24 hours. If matter is urgent, try https://t.me/kaction -- ___ bug-binutils mailing list bug-binutils@gnu.org https://lists.gnu.org/mailman/listinfo/bug-binutils
Re: How create small binaries with GNU binutils.
On Feb 01 2019, Dmitry Bogatov wrote: > results in huge binary: > > $ du -hb a.out > 4744a.out > $ strip -s a.out > $ du -hb a.out > 4408a.out > $ file a.out > a.out: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), statically > linked, stripped I cannot reproduce that. $ stat -c %s a.out 664 $ strip a.out $ stat -c %s a.out 344 $ size a.out textdata bss dec hex filename 13 0 0 13 d a.out $ rpm -q binutils binutils-2.31.90-lp150.5.68.1.x86_64 Try examining the files with `readelf -a'. Andreas. -- Andreas Schwab, sch...@linux-m68k.org GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1 "And now for something completely different." ___ bug-binutils mailing list bug-binutils@gnu.org https://lists.gnu.org/mailman/listinfo/bug-binutils
How create small binaries with GNU binutils.
[ Not a but, strictly speaking, but just do not know, where else to ask. ] Hello! I like AT&T syntax of amd64 assembler, so I am using GNU As. Unfortunately, it creates binries much bigger then one would expect from source code. For compraison, trivial program, that just exits with value 1 (essentially, /bin/false), implemented in fasm: ;; a02.fasm format ELF64 executable at 0001h segment readable executable entry $ xor edi,edi inc edi mov eax,60 syscall complied in following way $ fasm a02.fasm flat assembler version 1.73.06 (16384 kilobytes memory) 1 passes, 131 bytes. results in tiny binary. Equivalent program, compiled and linked with binutils # a01.S .globl _start _start: xor %di, %di inc %di mov $60, %eax syscall with following commands: as a01.S -o a01.o ld a01.o results in huge binary: $ du -hb a.out 4744a.out $ strip -s a.out $ du -hb a.out 4408a.out $ file a.out a.out: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), statically linked, stripped Both `as` and `ld` are from Debian package `binutils=2.31.1-11`. What am I doing wrong? Can I force binutils to create small, ~150 bytes binary? -- Note, that I send and fetch email in batch, once every 24 hours. If matter is urgent, try https://t.me/kaction -- pgpvu4cQu7dL_.pgp Description: PGP signature ___ bug-binutils mailing list bug-binutils@gnu.org https://lists.gnu.org/mailman/listinfo/bug-binutils
