Module Tolk.Compiler_metal

MTLCompiler, the private framework behind Metal's own compiler, compiles the source. It reads its options into LLVM's, which are global to a process, at every compile, so compiles run in processes of their own, which tolk starts from a program it carries: compiles from several domains run at once, and a compile that crashes ends its own process only. Each process serves compiles in turn, from any domain, and waits idle between them, so that loading MTLCompiler is paid once per process; a compile that finds none idle starts another, so a process's first compile also pays a process start. This process keeps as many as it ran compiles at once, a search's parallelism or the domains that compile a program's kernels, each holding about 13 MB of its own memory, more after a large kernel, until it exits. A process forked from this one starts its own and never uses its parent's. The program is written to Helpers.cache_dir, under a name holding its digest, or to the temporary directory if the cache cannot be written or the system refuses to run it from there. It runs only as a regular file of this user's that no other user can write, reached through no link and not quarantined, checked before each start and written again otherwise: where the system runs no program this process writes, every compile fails. The library is the file C.findlib finds for MTLCompiler when the compiler is made: the file MTLCOMPILER_PATH names, then macOS's private frameworks. Each process loads it. Only macOS has it. Making a compiler, and a compile its table holds, start no process.