Bug 6019 – [avr] avr-ld --relax requires --gc-sections

Bug 6019 - [avr] avr-ld --relax requires --gc-sections


Summary:	[avr] avr-ld --relax requires --gc-sections

Status:	RESOLVED FIXED

Product:	binutils
Classification:	Unclassified
Component:	ld
Version:	2.18

Importance:	P2 normal
Target Milestone:	---
Assigned To:	unassigned

URL:
Keywords:

Depends on:
Blocks:
	Show dependency tree / graph

Reported:	2008-03-31 22:26 UTC by Eric Weddington
Modified:	2008-06-04 09:59 UTC (History)
CC List:	1 user (show)

See Also:
Host:
Target:	avr--
Build:
Last reconfirmed:

Attachments
Test case. (41.65 KB, application/binary) 2008-05-25 20:14 UTC, Eric Weddington	Details
reduced test case (3.07 KB, text/plain) 2008-05-29 21:39 UTC, Jevin Sweval	Details
Add test for no local symbols (1.22 KB, patch) 2008-05-30 15:37 UTC, Nick Clifton	Details \| Diff
View All Add an attachment (proposed patch, testcase, etc.)

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Description Eric Weddington 2008-03-31 22:26:34 UTC

avr-ld fails with --relax, unless --gc-sections is also used, even if
-ffunction-sections is not used with avr-gcc.

Comment 1 Nick Clifton 2008-05-21 11:23:10 UTC

Hi Eric,

  Please can you provide a test case for this ?

Cheers
  Nick

Comment 2 Eric Weddington 2008-05-25 20:14:03 UTC

Created attachment 2756 [details]
Test case.

This zip file contains the source code of a project that exhibits the bug, and
it contains a short build script. This source code comes from WinAVR
(SourceForge) bug #1819125:
<http://sourceforge.net/tracker/index.php?func=detail&aid=1819125&group_id=68108&atid=520074>

Comment 3 Eric Weddington 2008-05-25 20:15:09 UTC

Unfortunately this is all I have in the way of test case. I know that it is too
large, but I haven't had time to investigate into a smaller test case.

Comment 4 Eric Weddington 2008-05-25 20:17:12 UTC

Note that in the build script, using -Wl,--relax causes ld to fail. Using
-Wl,--relax,--gc-sections causes the link to be successful. This is with a
host=mingw toolchain. I have not verified the bug on a host=linux toolchain.

Comment 5 Jevin Sweval 2008-05-29 21:39:59 UTC

Created attachment 2766 [details]
reduced test case

test with:
avr-gcc -c -o onewire.o -Os onewire.i
avr-gcc -Wl,--relax -o onewire.elf onewire.o

-Os is necessary and the linker doesn't crash with --gc-sections

Comment 6 Jevin Sweval 2008-05-29 21:42:47 UTC

I've attached a reduced test case made with multidelta. It got minimized to 11
meaningful lines. It was run through the preprocessor before minimization so the
actual code is hard to read but I doubt that really matters.

Comment 7 Nick Clifton 2008-05-30 15:37:17 UTC

Created attachment 2768 [details]
Add test for no local symbols

Comment 8 Nick Clifton 2008-05-30 15:38:42 UTC

Hi Eric, Hi Jevin,

  Please could you try out the uploaded patch and let me know if it works for
you ?  (I am especially interested to know if it works on the real programs
where you encountered this bug, not just the reduced testcase).

Cheers
  Nick

Comment 9 Eric Weddington 2008-06-02 16:37:20 UTC

Patch fixes bug on real-world application. 

Thanks, Nick!

Comment 10 Nick Clifton 2008-06-04 09:59:03 UTC

Hi Guys,

  Great - I have applied the patch along with the changelog entry below.

Cheers
  Nick

bfd/ChangeLog
	PR ld/6019
	* elf32-avr.c (elf32_avr_relax_section): Handle the case where
	there are no local symbols.