Client Code . Generated . libgccjit.so . code . . . JIT API . JIT "Frontend". (libbackend.a) .................................................................................... │ . . . . ──────────────────────────> . . . . │ . . . . V . . . . ──> libgccjit.cc . . . │ (error-checking). . . │ . . . ──> jit-recording.cc . . (record API calls) . . <─────── . . . │ . . <─────────────────────────── . . │ . . . . │ . . . . V . . gcc_jit_context_compile . ──────────────────────────> . . . . │ start of recording::context::compile () . . │ . . . . │ start of playback::context::compile () . . │ (create tempdir) . . . │ . . . . │ ACQUIRE MUTEX . . . │ . . . . V───────────────────────> toplev::main (for now) . . . . │ . . . . (various code) . . . . │ . . . . V . . . <───────────────── langhook:parse_file . . . │ . . . . │ (jit_langhook_parse_file) . . . │ . ..........................................│..................VVVVVVVVVVVVV... . . . │ . No GC in here . . . │ jit-playback.cc . . . │ (playback of API calls) . . . ───────────────> creation of functions, . . . . types, expression trees . . . <──────────────── etc . . . │(handle_locations: add locations to . . . │ linemap and associate them with trees) . . . │ . . . . │ . No GC in here ..........................................│..................AAAAAAAAAAAAA... . . . │ for each function . . . ──> postprocess . . . │ . . . . ────────────> cgraph_finalize_function . . . <──────────── . . . <── . . . . │ . . . . ──────────────────> (end of . . . . │ langhook_parse_file) . . . . │ . . . . (various code) . . . . │ . . . . ↓ . . . <───────────────── langhook:write_globals . . . │ . . . . │ (jit_langhook_write_globals) . . . │ . . . . │ . . . . ──────────────────> finalize_compilation_unit . . . . │ . . . . (the middle─end and backend) . . . . ↓ . . <───────────────────────────── end of toplev::main . . │ . . . . V───────────────────────> toplev::finalize . . . . │ (purge internal state) . . <──────────────────────── end of toplev::finalize . . │ . . . . V─> playback::context::postprocess: . . │ . . . . │ (assuming an in-memory compile): . . │ . . . . --> Convert assembler to DSO, via embedded . . copy of driver: . . driver::main () . . invocation of "as" . . invocation of "ld" . . driver::finalize () . . <---- . . │ . . . . │ . Load DSO (dlopen "fake.so") . . │ . . . . │ . Bundle it up in a jit::result . . <── . . . . │ . . . . │ RELEASE MUTEX . . . │ . . . . │ end of playback::context::compile () . . │ . . . . │ playback::context dtor . . ──> . . . . │ Normally we cleanup the tempdir here: . . │ ("fake.so" is unlinked from the . . │ filesystem at this point) . . │ If the client code requested debuginfo, the . . │ cleanup happens later (in gcc_jit_result_release) . . │ to make it easier on the debugger (see PR jit/64206) . . <── . . . . │ . . . . │ end of recording::context::compile () <─────────────────────────── . . │ . . . . V . . gcc_jit_result_get_code . ──────────────────────────> . . . . │ dlsym () within loaded DSO <─────────────────────────── . . Get (void*). . . . │ . . . . │ Call it . . . . ───────────────> . . . . │ . . . . │ . . . <─────────────── . . . │ . . . . etc│ . . . . │ . . . . V . . gcc_jit_result_release . ──────────────────────────> . . . . │ dlclose () the loaded DSO . . │ (code becomes uncallable) . . │ . . . . │ If the client code requested debuginfo, then . . │ cleanup of the tempdir was delayed. . . │ If that was the case, clean it up now. <─────────────────────────── . . │ . . . .