Posting compile tasks from the parser has several issues:

  1. We don't know how many functions there will be total, so we can't
     yet allocate shared_function_infos array on the Script
  2. Without this array, inner function compiles can't look up their own
     inner functions during bytecode finalization, so we can't run that
     finalization before script parse completes
  3. Scope analysis can't have run yet, so we can only post top-level
     function tasks and if we allocate SharedFunctionInfos early they
     are forced into a bit of a limbo state without an outer ScopeInfo.

Instead, we can post compile tasks during bytecode generation. Then, the
script parse is guaranteed to have completed, so we'll have a
shared_function_infos array and we will have allocated ScopeInfos
already. This also opens the door for posting tasks for compiling more
inner functions than just top-level, as well as generating better code
for functions/methods that reference same-script top-level
let/const/class.

Bug: chromium:1267680
Change-Id: Ie1a3a3c6f1b264c4ef28cd4763bfc6dc08f45d4d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3277884
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77894}