instead of recursion, callers of the function are responsible for
checking the respective tables that might have new entries in them and
then calling lowerZcuData again.
Recognize three distinct phases:
* before prelink ("object phase")
* after prelink, before flush ("zcu phase")
* during flush ("flush phase")
With this setup, we create data structures during the object phase, then
mutate them during the zcu phase, and then further mutate them during
the flush phase. In order to make the flush phase repeatable, the data
structures are copied just before starting the flush phase.
Further Zcu updates occur against the non-copied data structures.
What's not implemented is frontend garbage collection, in which case
some more changes will be needed in this linker logic to achieve a valid
state with data invariants intact.
fix some compilation errors for reworked Emit now that it's actually
referenced
introduce DataSegment.Id for sorting data both from object files and
from the Zcu.
introduce optimization: data segment sorting includes a descending sort
on reference count so that references to data can be smaller integers
leading to better LEB encodings. this optimization is skipped for object
files.
implement uav address access function which is based on only 1 hash
table lookup to find out the offset after sorting.
* function resolution now links to zcu_funcs, not navs_exe/navs_obj
* updateFunc now adds things to output functions
* updateNav now handles function aliases correctly
* only report start symbol missing when it is unresolved
mainly, rework how relocations works. This is the point at which symbol
indexes are known - not before. And don't emit unnecessary relocations!
They're only needed when emitting an object file.
Changes wasm linker to keep MIR around long-lived so that fixups can be
reapplied after linker garbage collection.
use labeled switch while we're at it
