Using a custom GNU Assembler version for GCC on OpenBSD 7.3

Iwan Luijks

When building NodeJS on OpenBSD you will likely run into the problem of the GNU Assembler (read gas) version being outdated and passing on --openssl-no-asm to the configure script.

You can't pass along the --with-as option to the configure script for NodeJS as it will simply ignore it (see configure.py for gas version detection). A simple trick will allow you to change the gas version for egcc (userland installed GCC).

Having installed GCC (thus you will have the egcc command available) as follows:

# pkg_info -Q gcc
# pkg_add gcc-8.4.0p15

Install gas:

# pkg_info -Q gas
# pkg_add gas-2.31.1
# whereis gas
/usr/local/bin/gas

Now move on creating a symlink to that gas binary in egcc's libexec:

# cd /usr/local/libexec/gcc/x86_64-unknown-openbsd7.3/8.4.0/  
# ln -s /usr/local/bin/gas as

Verify the gas version egcc uses, using the same command NodeJS uses to detect the gas version as follows:

# egcc -Wa,-v -c -o /dev/null -x assembler /dev/log
You should see GNU Assembler version 2.31.1 here.

See https://gcc.gnu.org/install/configure.html (look for --with-as) for more information on how GCC looks for the assembler. See https://github.com/nodejs/node/blob/main/configure.py on how NodeJS detects the GNU Assembler (gas) version.

This relates to errors you might get

Don't forget to install g++ too if necessary and set it as compiler in the session's environment using CXX=eg++.

Anyways, it relates to the warning "solvable" by passing --openssl-no-asm

# CC=egcc CXX=eg++ ./configure
Node.js configure: Found Python 3.11.4

ERROR: Did not find a new enough assembler, install one or build with
	--openssl-no-asm.
	Please refer to BUILDING.md

Or the error about missing instructions:

Error: no such instruction: `pmaxud %xmm2,%xmm1`

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