Emscripten currently implements `emscripten_return_address()` by calling
out into JavaScript and parsing a stack trace, which introduces
significant overhead that we would prefer to avoid in release builds.
This is especially problematic for allocators because the generic parts
of `std.mem.Allocator` make frequent use of `@returnAddress`, even
though very few allocator implementations even observe the return
address, which makes allocators nigh unusable for performance-critical
applications like games if the compiler is unable to devirtualize the
allocator calls.
The code did one useless thing and two wrong things:
- ref counting was basically a noop
- last_dir_fd was chosen from the wrong index and also under the wrong
condition
This caused regular crashes on macOS which are now gone.
* use `tmp.dir.realpathAlloc()` to get full path into tmpDir instances
* use `testing.allocator` where that simplifies things (vs. manual ArenaAllocator for 1 or 2 allocs)
* Trust `TmpDir.cleanup()` to clean up contained files and sub-trees
* Remove some unnecessary absolute paths (enabling WASI to run the tests)
* Drop some no-longer necessary `[_][]const u8` casts
* Add scopes to reduce `var` usage in favor of `const`
This commits adds the following distinct integer types to std.zig.Ast:
- OptionalTokenIndex
- TokenOffset
- OptionalTokenOffset
- Node.OptionalIndex
- Node.Offset
- Node.OptionalOffset
The `Node.Index` type has also been converted to a distinct type while
`TokenIndex` remains unchanged.
`Ast.Node.Data` has also been changed to a (untagged) union to provide
safety checks.
This function checks for various possibilities that are never produced
by the parser.
Given that lastToken is unsafe to call on an Ast with errors, I also
removed code paths that would be reachable on an Ast with errors.
The bitcode format always uses little endian words. Prior to this commit, a
bitcode file produced on e.g. aarch64_be or s390x would fail to be loaded by
LLVM.
The Bernstein-Yang inversion code was meant to be used only with the
fields we currently use for the NIST curves.
But people copied that code and were confused that it didn't work as
expected with other field sizes.
It doesn't cost anything to make it work with other field sizes,
that may support in the future. So let's do it.
This also reduces the diff with the example zig code in fiat crypto.
Suggested by @Rexicon226 -- Thank you!
This reverts commit dea72d15da4fba909dc3ccb2e9dc5286372ac023, reversing
changes made to ab381933c87bcc744058d25a876cfdc0d23fc674.
The changeset does not work as advertised and does not have sufficient
test coverage.
Reopens#22822
