Error When Cross-Compiling for Arm Using Newlib Nano Libs

Sylvester Ink · 02-26-2020, 07:09 PM

I'm trying to build an Arm project using the arm-gcc cross compiler along with the libraries in the newlib package. It builds just fine, but when it comes to linking, I get the following error:

Code:

/usr/bin/arm-none-eabi-ld: cannot find -lg_nano
/usr/bin/arm-none-eabi-ld: cannot find -lstdc++_nano
/usr/bin/arm-none-eabi-ld: cannot find -lc_nano
/usr/bin/arm-none-eabi-ld: cannot find -lc_nano

I am using the following linker flag:

Code:

-specs=nano.specs

This is to use the libraries optimized to be smaller and lighter for embedded devices. If I remove that particular flag, it builds just fine.

Both arm-gcc and newlib are from Slackbuilds.org, and the arm-gcc Slackbuild script has been altered to add support for the c++ language.

Is newlib compiled without nano support? If that's the case, why is the nano.specs file available in the package? Also, what would I need to change in the Slackbuild in order for newlib to be built with support?

philanc · 02-27-2020, 03:45 PM

Quote:

Originally Posted by Sylvester Ink

I'm trying to build an Arm project using the arm-gcc cross compiler along with the libraries in the newlib package. It builds just fine, but when it comes to linking, I get the following error:

Code:

/usr/bin/arm-none-eabi-ld: cannot find -lg_nano
/usr/bin/arm-none-eabi-ld: cannot find -lstdc++_nano
/usr/bin/arm-none-eabi-ld: cannot find -lc_nano
/usr/bin/arm-none-eabi-ld: cannot find -lc_nano

I am using the following linker flag:

Code:

-specs=nano.specs

This is to use the libraries optimized to be smaller and lighter for embedded devices. If I remove that particular flag, it builds just fine.

Both arm-gcc and newlib are from Slackbuilds.org, and the arm-gcc Slackbuild script has been altered to add support for the c++ language.

Is newlib compiled without nano support? If that's the case, why is the nano.specs file available in the package? Also, what would I need to change in the Slackbuild in order for newlib to be built with support?

As far as I know, 'nano' is not a build option for newlib, but a distinct libc named "newlib-nano" initially provided by ARM Ltd in their cross development toolchain.

I don't think that the newlib package from SBo can build newlib-nano. In the newlib tree, what nano.spec file did you use?

On the other hand, there may be a way to build newlib with the newlib/libc/stdio/nano_xxx files (vfprintf and others) to reduce the libc size but I don't know how to do it.

Sylvester Ink · 02-28-2020, 02:05 AM

Quote:

Originally Posted by philanc

As far as I know, 'nano' is not a build option for newlib, but a distinct libc named "newlib-nano" initially provided by ARM Ltd in their cross development toolchain.

I don't think that the newlib package from SBo can build newlib-nano. In the newlib tree, what nano.spec file did you use?

On the other hand, there may be a way to build newlib with the newlib/libc/stdio/nano_xxx files (vfprintf and others) to reduce the libc size but I don't know how to do it.

That's odd, because the newlib package from SBo contains the nano.specs file.

Code:

/usr/arm-none-eabi/lib/nano.specs
/usr/arm-none-eabi/lib/thumb/nano.specs
/usr/arm-none-eabi/lib/thumb/autofp/v7/fpu/nano.specs
/usr/arm-none-eabi/lib/arm/autofp/v5te/fpu/nano.specs

I'm pretty sure I was using the first one, though all four are the same:

Code:

%rename link                nano_link
%rename link_gcc_c_sequence                nano_link_gcc_c_sequence
%rename cpp_unique_options              nano_cpp_unique_options
 
*cpp_unique_options:
-isystem =/include/newlib-nano %(nano_cpp_unique_options)
 
*nano_libc:
-lc_nano
 
*nano_libgloss:
%{specs=rdimon.specs:-lrdimon_nano} %{specs=nosys.specs:-lnosys}
 
*link_gcc_c_sequence:
%(nano_link_gcc_c_sequence) --start-group %G %(nano_libc) %(nano_libgloss) --end-group
 
*link:
%(nano_link) %:replace-outfile(-lc -lc_nano) %:replace-outfile(-lg -lg_nano) %:replace-outfile(-lrdimon -lrdimon_nano) %:replace-outfile(-lstdc++ -lstdc++_nano) %:replace-outfile(-lsupc++ -lsupc++_nano)
 
*lib:
%{!shared:%{g*:-lg_nano} %{!p:%{!pg:-lc_nano}}%{p:-lc_p}%{pg:-lc_p}}

I've seen it mentioned elsewhere that newlib can be built with nano, though it's hard to find consistent configure flags that do it.