ldc/docs/dynamic_compile_bind.md

Dynamic compile bind

D part

• bind function returns BindPtr object which is reference counted internally
• BindPtr have opCall and toDelegate methods to call directly or create D delegate
• On creation BindPtr call void registerBindPayload(void* handle, void* originalFunc, void* exampleFunc, const ParamSlice* params, size_t paramsSize) function
  • handle - pointer to pointer to function, which uniquely identifies bind object, actual function pointer to generated code will be written here during compileDynamicCode call.
  • originalFunc - pointer to original function, this is special function, generated inside bind, which just forwards parameter to user function or delegate, this function always have @dynamicCompileEmit attribute, so jit runtime will fins it even if user function wasn't marked @dynamicCompile
  • exampleFunc - special function with parameters matched to original user function, runtime will extracts parameters types from it, never called
  • params - list of slices to bind parameters, will be null for placeholders
  • paramsSize - items count in params
• On destruction BindPtr call void unregisterBindPayload(void* handle);
  • handle - same handle as passed in registerBindPayload previously

Runtime part

• registerBindPayload add handle to internal list
• During compileDynamicCode
  • generateBind - Generate new function for each bind handle
    • Parse each bind parameter into llvm constant using existing parseInitializer (previously used for @dynamicCompileConst)
    • If parameter is function pointer from another bind handle, replace with direct reference to that function
    • Generate call to original function (this call will be inlined)
  • Generate and optimize module as usual
  • applyBind - update handles to generated code