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ocaml / flexdll

a dlopen-like API for Windows
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Add "incbin" functionality #93

Closed nojb closed 1 year ago

nojb commented 2 years ago

This PR adds an "incbin" (see https://github.com/graphitemaster/incbin) feature to flexdll, allowing to include binary blobs in the final binary. The motivation is https://github.com/ocaml/ocaml/pull/10159 and https://github.com/ocaml/ocaml/pull/10654, namely including debug information for bytecode binaries built with --output-complete-exe with MSVC, but the functionality makes sense independently.

Concretely, a new flag -incbin <sym> <file> is added which has the effect of embedding <file> inside the final binary and defining two symbols: <sym>_data and <sym>_size: <sym>_data points to the beginning of the binary blob, and <sym>_size is a 32-bit int containing the size of the binary blob.

I'm still testing it, but feedback would be welcome!

dra27 commented 1 year ago

It's not a strong enough objection to say "this shouldn't be in flexlink", but it does a feel little as though a compiler function is being added to a linker largely because the linker has the Coff module 🙂

I'm vaguely wondering if either #embed (C23, so it might be prudent not to hold our breath!) or a solution based on resource files might be better for this in the long run? I don't have any performance evidence, but I'm wondering if there's a reason that PDB is always in a separate file i.e. while in ELF we can clearly have the debugging information present with no issue, I'm left wondering why PE goes to great lengths to reference external debugging data, rather than ever allowing it to be embedded.

nojb commented 1 year ago

You are right; I'm also not convinced of the approach (I closed https://github.com/ocaml/ocaml/pull/10654). Let's close this for now.