For tasks codegen for private/firstprivate variables are different rather than for other directives.
- Build an internal structure of privates for each private variable:
struct .kmp_privates_t. { Ty1 var1; ... Tyn varn; };
- Add a new field to kmp_task_t type with list of privates.
struct kmp_task_t { void * shareds; kmp_routine_entry_t routine; kmp_int32 part_id; kmp_routine_entry_t destructors; .kmp_privates_t. privates; };
- Create a function with destructors calls for all privates after end of task region.
kmp_int32 .omp_task_destructor.(kmp_int32 gtid, kmp_task_t *tt) { ~Destructor(&tt->privates.var1); ... ~Destructor(&tt->privates.varn); return 0; }
- Perform initialization of all firstprivate fields (by simple copying for POD data, copy constructor calls for classes) + provide address of a destructor function after kmpc_omp_task_alloc() and before kmpc_omp_task() calls.
kmp_task_t *new_task = __kmpc_omp_task_alloc(ident_t *, kmp_int32 gtid, kmp_int32 flags, size_t sizeof_kmp_task_t, size_t sizeof_shareds, kmp_routine_entry_t *task_entry); CopyConstructor(new_task->privates.var1, *new_task->shareds.var1_ref); new_task->shareds.var1_ref = &new_task->privates.var1; ... CopyConstructor(new_task->privates.varn, *new_task->shareds.varn_ref); new_task->shareds.varn_ref = &new_task->privates.varn; new_task->destructors = .omp_task_destructor.; kmp_int32 __kmpc_omp_task(ident_t *, kmp_int32 gtid, kmp_task_t *new_task)