options which are passed to configurer and therefore observable by the
build script are added to the cache hash. A sorted list is hashed since
they are unordered.
I had this idea to make b.dupe() also intern the strings since they will
be ultimately serialized to Configuration. Unfortunately the idea does
not work, because although a process-lived arena is used for the
string_bytes ArrayList of the Configuration.Wip, when the ArrayList is
resized, Allocator.free() memsets the freed memory to undefined, even
though it still technically lives due to being in a process-scoped
arena. So this commit will need to be partially reverted. However, I
kept it for posterity, and there are some more changes which I will now
note below.
- dupePaths: don't rewrite backslashes to forward slashes. backslashes
are valid in filenames on non-windows systems.
- always compile configurer in single-threaded mode
- use arena allocator for everything, no gpa for anything
- construct the Configuration.Wip instance earlier, so some stuff can be
prepopulated as desired.
- don't forget to flush
Number of generated files is recorded in serialized Configuration. Maker
preallocates array of generated files so that loads and stores can be
synchronization-free (protected by the dependency tree ordering).
More progress on Compile Step Zig CLI lowering.
next thing to do is figure out how LazyPath is supposed to work now.
something like this:
* each Step that provides LazyPath objects has a setLazyPath and
getLazyPath function which takes a tagged union identifying which one
to access
* steps that fulfill LazyPath objects can freely call setLazyPath
without obtaining a lock because the dependency graph prevents
simultaneous access.
* similarly, steps that access LazyPath results can freely call
getLazyPath without obtaining a lock, because after modification,
there may be simultaneous reads from dependencies but they will all be
read-only
* a fulfilled LazyPath object is a read-only std.Build.Cache.Path.
Andrew Kelley