# New Ticket Created by Allison Randal # Please include the string: [perl #58414] # in the subject line of all future correspondence about this issue. # <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=58414 >
Briefly discussed in a phone call with Patrick, Jerry, and chromatic: Our calling conventions have grown in an organic fashion over the past few years, and they're showing some signs of cruft. The current design and implementation could use a consistency review. Among the topics for review: - VTABLE_invoke is inconsistent between different sub-like PMCs. For most subs it simply sets up the environment for invocation, and selects the first opcode instruction of the sub as the next 'opcode_t *' for 'runops'. For NCI subs it actually invokes the function pointer. The disjoint means that NCI subs can't be invoked from C argument lists the same way as all the other subs (because the regular C argument list passing can only happen *after* VTABLE_invoke has been called to set up the environment, but NCI requires the arguments to be passed *before* the call to VTABLE_invoke). - Also, VTABLE_invoke can't really be overridden from PIR, because it requires direct access to low-level interpreter data structures. - Standardize on PCC-style signature description strings throughout the system (instead of different signature description strings for NCI, PCC, and regular subs). - Refactor to remove code duplication between the various dispatch systems. - Optimize PCC dispatch (refactor to slim down the code). - Enable dispatching by CallSignature PMC everywhere. Some of these elements may be post-1.0 features. Consider this ticket a collection point for calling convention issues, and link in related tickets. Allison
