Support for allocation of executable memory

[Felix Cravic]

I agree that there are reasons why it could not have its place in Panama, like OS limitations complicating the API design & it being another pretty unsafe feature.
I however disagree with the "just", which would involve maintaining a native dependency and building it for every potential platform, not to mention the fact that every execution will have to pass through JNI/Linker API. By that point I doubt that Java would be the right tool for the job, or is it perhaps what you meant?
________________________________
De : Glavo <zjx001202 at gmail.com>
Envoyé : dimanche 21 novembre 2021 19:19
À : Felix Cravic <themode at outlook.fr>
Cc : panama-dev at openjdk.java.net <panama-dev at openjdk.java.net>
Objet : Re: Support for allocation of executable memory

I don't think Panama should provide special support for it.

To do this, you just need to create the binding of the relevant system API (e.g. `VirtualAlloc` and `VirtualProtect` on Windows, or `mmap` on Linux) with the foreign linker API and call it.

Felix Cravic <themode at outlook.fr<mailto:themode at outlook.fr>> 于2021年11月22日周一 上午1:01写道：
Hello, I was wondering if there has ever been any discussion about supporting allocation of executable memory (and then its execution). The use cases I have in mind are emulation, very hot paths requiring specialized assembly (which could still fallback to jvm bytecode if unavailable), and a potential option to keep the whole application written in a JVM language.

I doubt that such addition would drastically change the API, perhaps some concern about OS specific restrictions (e.g. write-xor-execute memory protection), and platform not supporting JIT compilation at all (IOS, potentially problematic for Graal & project Leyden)

Discussion would be appreciated!