Newlib's libgloss is not optimized for size even if "--specs=nano.specs" are used

[abrodkin]

Even if a user attempts to generate the smallest possible resulting binary specifying --specs=nano.specs board-specific libs like libnsim.a, libqemu.a etc are used from "normal" (non-"nano" build) of the Newlib, thus contributing to the resulting binary size.

[claziss]

Why should we care about this? libnsim.a and libqemu.a are simulation only libraries. No reason to optimize them as they will never be used in production.

[abrodkin]

Fair enough, though why do ARM folks do that for "semi-hosting"? See https://github.com/foss-for-synopsys-dwc-arc-processors/newlib/blob/arc-2021.03/libgloss/arm/elf-rdimon.specs#L14:

# rdimon.specs
#
# Spec file for AArch64 baremetal newlib with version 2 of the
# AngelAPI semi-hosting using the SVC trap instruction.

...

*rdimon_libgloss:
%{!specs=nano.specs:-lrdimon} %{specs=nano.specs:-lrdimon_nano}

What about libdw_uart.a, what if it is used in production?

[claziss]

You need to ask them :)

[abrodkin]

What about libdw_uart.a?

[abrodkin]

And also even though we build & install "nano" version of libm.a (libm_nano.a) we don't replace -lm with lm_nano in `nano.specs, while RISCV folks do, see https://www.sourceware.org/git/?p=newlib-cygwin.git;a=blob;f=libgloss/riscv/nano.specs:

*link:
%(nano_link) %:replace-outfile(-lc -lc_nano) %:replace-outfile(-lg -lg_nano) %:replace-outfile(-lm -lm_nano)

[claziss]

What about libdw_uart.a?

My understanding is that you want to remove it (or refactor it?). You can pick this issue and make it part of your proposed solution.

[claziss]

And also even though we build & install "nano" version of libm.a (libm_nano.a) we don't replace -lm with lm_nano in `nano.specs, while RISCV folks do, see https://www.sourceware.org/git/?p=newlib-cygwin.git;a=blob;f=libgloss/riscv/nano.specs:

*link:
%(nano_link) %:replace-outfile(-lc -lc_nano) %:replace-outfile(-lg -lg_nano) %:replace-outfile(-lm -lm_nano)

libm is not libgloss :) Of course you can add a simple patch that is doing this.