Next: Registering Code, Up: JIT Interface
These are the relevant struct declarations that a C program should include to implement the interface:
typedef enum { JIT_NOACTION = 0, JIT_REGISTER_FN, JIT_UNREGISTER_FN } jit_actions_t; struct jit_code_entry { struct jit_code_entry *next_entry; struct jit_code_entry *prev_entry; const char *symfile_addr; uint64_t symfile_size; }; struct jit_descriptor { uint32_t version; /* This type should be jit_actions_t, but we use uint32_t to be explicit about the bitwidth. */ uint32_t action_flag; struct jit_code_entry *relevant_entry; struct jit_code_entry *first_entry; }; /* GDB puts a breakpoint in this function. */ void __attribute__((noinline)) __jit_debug_register_code() { }; /* Make sure to specify the version statically, because the debugger may check the version before we can set it. */ struct jit_descriptor __jit_debug_descriptor = { 1, 0, 0, 0 };
If the JIT is multi-threaded, then it is important that the JIT synchronize any modifications to this global data properly, which can easily be done by putting a global mutex around modifications to these structures.