Suppressing 'discarded sections' in linker map?

[scottm]

Is there a way to avoid generating the 'discarded input sections' portion of the linker map file?  The map file is a great resource, but it gives me just over 25,000 lines of absolutely useless entries, mostly in .debug_macro and .group.  I'm having a heck of a time finding any information on where those come from and how to get rid of them.

Thanks,

Scott

[scottm]

Wanted to share my solution - turns out I don't need to dig that out of the map file, MCUX's Symbol Viewer does a pretty good job of extracting everything from the ELF file.  It's sortable by size or address and you can sort within a section, which is exactly what I'm after.

[Alexis_A]

Hi Scott,

Thanks for sharing your solution.

Best Regards,

Alexis Andalon

[Alexis_A]

Hi Scott,

Sometimes the compiler detect that a variable or a function isn't necessary and optimize it, this can be seen in this section.

But this isn't relevant for your implementation, as you see in the image, this not has a memory location assigned.

 

I hope this helps you.

Best Regards,

Alexis Andalon

[scottm]

Yes, I understand that, but how do I stop it from outputting that?  Or is there a tool I can use to easily generate a linker map that only lists things actually placed in memory?  I often need to consult the linker map to see how much space things are using and it's hard to do when 95% of the file is garbage.

Thanks,

Scott

[converse]

I think you’ll need to write yourself a script to filter out these line. I’d suggest using (g)awk.

[scottm]

This is one of those things that makes me wonder what I'm doing so differently that this is a difficult thing to do.  On the HC08 the linker map output was nicely formatted and readable without a lot of excess cruft, and while the ARM linker's map file is more standard, I can't find any off-the-shelf tools that let me view it in a useful manner.

I've got AMAP and it'll parse the files, but it doesn't distinguish between things that go in memory (which are the only things I care about in this context) and debug objects, and it doesn't let you sort by size within a section.

What I'm usually doing is looking for hogs - things in RAM taking more space than I expect, things that don't need to be there at all like USB descriptors only used during enumeration but placed in RAM by default, and code that's bloated.

I can cut out the 'discarded sections' part of the linker map and drop all of the .debug* sections and get AMAP's display down to something reasonable, but because of its limited sorting options I can't separate RAM from ROM objects and they're all mixed in together.

What's everyone else use to keep an eye on their memory usage?

Scott

[Alexis_A]

Hi Scott,

I couldn't find any way to hide this section. I will suggest to check the ARM Compiler armlink User Guide, there should be a way to hide this section when the .map is created.

You can find the -Xlinker commands used for the default project in the project options - C/C++ Build - Settings - MCU Linker - Miscellaneous.

Best Regards,

Alexis Andalon

[scottm]

Thanks, I've looked it over but I can't find anything on controlling the map output, other than turning it on or off.  I can exclude sections from linking, but not from the map as far as I can see.