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Sloeber / arduino-eclipse-plugin

A plugin to make programming the arduino in eclipse easy
https://eclipse.baeyens.it/
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MEGA2560 needs --relax option when linking #270

Closed FredericG-BE closed 9 years ago

FredericG-BE commented 9 years ago

See https://code.google.com/p/arduino/issues/detail?id=729 http://www.atmel.com/webdoc/AVRLibcReferenceManual/FAQ_1faq_funcptr_gt128kib.html

When compiling with Arduino IDE: C:\ProgramFiles\Arduino\hardware\tools\avr\bin\avr-gcc -Os -Wl,--gc-sections,--relax -mmcu=atmega2560 -o ....

When compiling with Eclipse: "C:/ProgramFiles/Arduino/hardware/tools/avr/bin/avr-gcc" -Os -Wl,--gc-sections -mmcu=atmega2560 -o ...

I changed the line in platform.txt to compiler.c.elf.flags=-Os -Wl,--gc-sections,--relax
and all seems fine...

jantje commented 9 years ago

Wierd. The word "relax" is nowhere found in the platform nor the boards.txt file in arduino ide 1.6.1. It looks like a hardcoded thing. Note that your solution is only ok if you actually use a mega. I assume other boards will make bigger elf files with this option. I guess it is the right time to think about adding an option to extend the linker and archiver command line. Next to opening an issue at arduino's

FredericG-BE commented 9 years ago

Indeed, the option that I added to platform.txt is just to keep me going and to demonstrate that it indeed fixes the issue I was facing; removing it and it comes back. I also suspect that this option comes at a price.

jantje commented 9 years ago

I had an issue with a mega and I wanted to be sure it was not related to this --relax option so I thought about a good workaround. What I did was add these lines to the boards.txt containing the mega. mega.compiler.c.elf.flags={compiler.warning_flags} -Os -Wl,--gc-sections,--relax megaADK.compiler.c.elf.flags={compiler.warning_flags} -Os -Wl,--gc-sections,--relax These lines are ignored by the arduino IDE so it is a safe workaround.

jantje commented 9 years ago

I build a additional framework in the plugin that allows me to add mega.compiler.c.elf.flags={compiler.warning_flags} -Os -Wl,--gc-sections,--relax megaADK.compiler.c.elf.flags={compiler.warning_flags} -Os -Wl,--gc-sections,--relax in the plugin. I tested it on my system and it works fine I'm not sure we will make the framework part of the release @rlogiacco is working on.