abhishek-samsung opened a new issue, #11689:
URL: https://github.com/apache/nuttx/issues/11689
When we are trying to build elf along with exceptions (stm32f4discovery elf
config with uClib++ and exceptions enabled), some extra sections are getting
created (without following the linker script).
```
abhishek@Linux:~/Work/public/nuttx_build/apps$ readelf -S --wide libapps.a
.
.
.
File:
libapps.a(helloxx_main.cxx.home.abhishek.Work.public.nuttx_build.apps.examples.helloxx_1.o)
There are 34 section headers, starting at offset 0xa00:
Section Headers:
[Nr] Name Type Addr Off Size ES Flg Lk
Inf Al
[ 0] NULL 00000000 000000 000000 00 0
0 0
[ 1] .group GROUP 00000000 000034 000014 04 31
37 4
[ 2] .text PROGBITS 00000000 000048 000000 00 AX 0
0 1
[ 3] .data PROGBITS 00000000 000048 000000 00 WA 0
0 1
[ 4] .bss NOBITS 00000000 000048 000000 00 WA 0
0 1
[ 5] .text._ZN11CHelloWorldD2Ev PROGBITS 00000000 000048 000002 00
AXG 0 0 2
[ 6] .ARM.extab.text._ZN11CHelloWorldD2Ev PROGBITS 00000000 00004a
000000 00 AG 0 0 1
[ 7] .ARM.exidx.text._ZN11CHelloWorldD2Ev ARM_EXIDX 00000000 00004c
000008 00 ALG 5 0 4
[ 8] .rel.ARM.exidx.text._ZN11CHelloWorldD2Ev REL 00000000
0006b4 000008 08 IG 31 7 4
[ 9] .rodata._ZN11CHelloWorld10HelloWorldEv.isra.0.str1.1 PROGBITS
00000000 000054 000056 01 AMS 0 0 1
[10] .text._ZN11CHelloWorld10HelloWorldEv.isra.0 PROGBITS 00000000
0000ac 000018 00 AX 0 0 4
[11] .rel.text._ZN11CHelloWorld10HelloWorldEv.isra.0 REL
00000000 0006bc 000018 08 I 31 10 4
[12] .ARM.extab.text._ZN11CHelloWorld10HelloWorldEv.isra.0 PROGBITS
00000000 0000c4 000000 00 A 0 0 1
[13] .ARM.exidx.text._ZN11CHelloWorld10HelloWorldEv.isra.0 ARM_EXIDX
00000000 0000c4 000008 00 AL 10 0 4
[14] .rel.ARM.exidx.text._ZN11CHelloWorld10HelloWorldEv.isra.0 REL
00000000 0006d4 000008 08 I 31 13 4
[15] .rodata.helloxx_main.str1.1 PROGBITS 00000000 0000cc 0000cf 01
AMS 0 0 1
[16] .text.helloxx_main PROGBITS 00000000 00019c 000058 00 AX 0
0 4
[17] .rel.text.helloxx_main REL 00000000 0006dc 000040 08 I
31 16 4
[18] .ARM.extab.text.helloxx_main PROGBITS 00000000 0001f4 000000
00 A 0 0 1
[19] .ARM.exidx.text.helloxx_main ARM_EXIDX 00000000 0001f4 000008
00 AL 16 0 4
[20] .rel.ARM.exidx.text.helloxx_main REL 00000000 00071c
000010 08 I 31 19 4
[21] .text.startup._GLOBAL__sub_I_helloxx_main PROGBITS 00000000
0001fc 000020 00 AX 0 0 4
[22] .rel.text.startup._GLOBAL__sub_I_helloxx_main REL
00000000 00072c 000020 08 I 31 21 4
[23] .ARM.extab.text.startup._GLOBAL__sub_I_helloxx_main PROGBITS
00000000 00021c 000000 00 A 0 0 1
[24] .ARM.exidx.text.startup._GLOBAL__sub_I_helloxx_main ARM_EXIDX
00000000 00021c 000008 00 AL 21 0 4
[25] .rel.ARM.exidx.text.startup._GLOBAL__sub_I_helloxx_main REL
00000000 00074c 000008 08 I 31 24 4
[26] .init_array INIT_ARRAY 00000000 000224 000004 04 WA 0
0 4
[27] .rel.init_array REL 00000000 000754 000008 08 I 31
26 4
[28] .bss._ZL12g_HelloWorld NOBITS 00000000 000228 000004 00 WA
0 0 4
[29] .comment PROGBITS 00000000 000228 00004a 01 MS 0
0 1
[30] .ARM.attributes ARM_ATTRIBUTES 00000000 000272 00002e 00 0
0 1
[31] .symtab SYMTAB 00000000 0002a0 000320 10 32
41 4
[32] .strtab STRTAB 00000000 0005c0 0000f1 00 0
0 1
[33] .shstrtab STRTAB 00000000 00075c 0002a1 00 0
0 1
Key to Flags:
W (write), A (alloc), X (execute), M (merge), S (strings), I (info),
L (link order), O (extra OS processing required), G (group), T (TLS),
C (compressed), x (unknown), o (OS specific), E (exclude),
y (purecode), p (processor specific)
File:
libapps.a(dummy.c.home.abhishek.Work.public.nuttx_build.apps.platform_1.o)
There are 9 section headers, starting at offset 0x16c:
.
.
```
But, as per the elf loader code, we are only considering one ARM.exidx
section in up_init_exidx,
https://github.com/apache/nuttx/blob/72f9bd142f2f50bbd68548700c30be3b161462ff/binfmt/libelf/libelf_load.c#L408-L420
Why are the other sections not considered? Also, why is the out file not
following the linker script, why are new sections created?
I have integrated the elf loading (binfmt/libelf) in my project and I am
trying to enabled cpp exceptions. I am stuck with the issue I have mentioned
above. I couldn't check if the config works fine as I don't have
stm32f4discovery board but I am able to verify that the same sections are
getting created in nuttx too. Is this expected behavior? Is there a way to
avoid these additional sections?
I have fixed some build issues when building the above config, so have fixed
them in the below PRs.
https://github.com/apache/nuttx/pull/11688
https://github.com/apache/nuttx-apps/pull/2286
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
