ability to specify the file path basename of build artifacts (including extension)

[tiehuis]

Accepted Proposal

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For example zig build-exe t.zig --emit llvm-ir --name output generates the output file output.ll when it should use only the name field and not add an extension. It is expected to generate output bit code to output.

This is the same for zig build-exe t.zig --emit asm --name output, which generates output.s.

Marking as a bug since I don't think this is the intended behavior.

This issue came up here: compiler-explorer/compiler-explorer#1328.

[daurnimator]

See also #2231

[andrewrk]

Hold on for a second, it actually is intentional. (Though the fact that it appears unintentional is problematic and worth addressing)

So the deal is that with a several of the build options, zig produces more than one build artifact. For example for a libraries and objects, zig produces libfoo.a and foo.h. For dynamic libraries, the name + the major version is used as the SONAME. I think there are one or two more examples.

Point being we have the concept of the "name" of the thing being built independent from the "output file". If --name is changed to mean output file, then we have to solve the problem of multiple output files and places that use the concept of the name.

[tiehuis]

Ahh, I overlooked the case of build-lib and related. I'll have a think and add an alternative to account for the multiple artifact case. I do feel like it is valuable to have name be adhered to completely and not implicitly changed by other flags, however.

[andrewrk]

We're moving to a convention where building something has an "artifact directory" which can be in the cache or it can be provided by --output-dir. In this directory can be any number of things, which can be enabled or disabled. For example:

• -femit-docs and -fno-emit-docs toggle outputting generated documentation
• -femit-bin and -fno-emit-bin toggle outputting object/lib/executable

--emit is deprecated; all 3 of the choices should be separate togglable things to output (asm, llvm-ir, machine code). One thing we could do to address this issue is to have the standard "emit" options all have a uniform way of overriding the file path basename. By default this would be the --name + appropriate extension, but could be overridden.

This way we can still use artifact directories, making this strategy cache friendly, but still have the user have a way to decide the filename.