Is “would” accompanied with present perfect?

Question

  "Ah, poor James!" she said. "God knows we done all we could, as poor as we are—we wouldn't see him want anything while he was in it."
  Nannie had leaned her head against the sofa-pillow and seemed about to fall asleep.
   "There's poor Nannie," said Eliza, looking at her, "she's wore out. All the work we had, she and me, getting in the woman to wash him and then laying him out and then the coffin and then arranging about the Mass in the chapel. Only for Father O'Rourke I don't know what we'd have done at all. It was him brought us all them flowers and them two candlesticks out of the chapel and wrote out the notice for the Freeman's General and took charge of all the papers for the cemetery and poor James's insurance." (James Joyce, Dubliners)

What has ‘would’ been put in the clause for? When I back-shift the sentence, “I didn't know what we'd do at all”, it’s not likely what the context says. Is the original a present perfect, and ‘would’ is weakening the meaning of ‘don’t know’? (or does 'only for' mean 'without'?)

Answer 1

This is the consequence clause of a conditional construction in which the condition clause is headed by only for.

Only for means “but for, if it were not for”; your without is a pretty good guess. It was at one time generally current in informal use, but OED 1, s.v. Only, B. Conjunctive adv.,conj. (prep.) 2. says (in 1902) that is ‘Now only dial.’, and it does not appear in either the Oxford Dictionaries or in Merriam-Webster. The dialectal use is however fairly widespread: I heard it occasionally in Alabama in the 1950s and 1960s, and in the Ozarks in the 1980s. It is hardly surprising that it should have been current in Joyce's Dublin; Bernard Shaw, a generation older than Joyce, observes somewhere that the Dublin of his youth was an 18th-century town.

At all at the end of a sentence is an Irishism; entirely may also occur in this position, with the same sense.

So the sentence may be paraphrased:

If it were not for Father O'Rourke I have absolutely no idea what we would have done.

Answer 2

I would go there---Conditional tense.

I would have gone there---Conditional Perfect tense.

I would be going there---Conditional Progressive tense.

I would have been going there---Conditional Perfect Progressive tense.