The current target's ABI cannot be relied on for this.
For example, we may build the zig compiler for target
riscv64-linux-musl and provide a tarball for users to
download. A user could then run that zig compiler on
riscv64-linux-gnu. This use case is well-defined and
supported by Zig. But that means that we must detect
the system ABI here rather than
relying on `std.Target.current`.
Some C compilers, such as Clang, are known to rely on
argv[0] to find the path to their own executable,
without even bothering to resolve PATH. This results
in the message:
error: unable to execute command: Executable "" doesn't exist!
So we tell ChildProcess to expand argv[0] to the absolute path
to give them a helping hand.
Rather than `zig0 build ...` the build now does
`zig0 build-lib ...`, avoiding the requirement of linking the build
script, and thus avoiding the requirement of finding native libc,
for systems where libc is the system ABI.
* libc_installation.cpp is deleted.
src-self-hosted/libc_installation.zig is now used for both stage1 and
stage2 compilers.
* (breaking) move `std.fs.File.access` to `std.fs.Dir.access`. The API
now encourages use with an open directory handle.
* Add `std.os.faccessat` and related functions.
* Deprecate the "C" suffix naming convention for null-terminated
parameters. "C" should be used when it is related to libc. However
null-terminated parameters often have to do with the native system
ABI rather than libc. "Z" suffix is the new convention. For example,
`std.os.openC` is deprecated in favor of `std.os.openZ`.
* Add `std.mem.dupeZ` for using an allocator to copy memory and add a
null terminator.
* Remove dead struct field `std.ChildProcess.llnode`.
* Introduce `std.event.Batch`. This API allows expressing concurrency
without forcing code to be async. It requires no Allocator and does
not introduce any failure conditions. However it is not thread-safe.
* There is now an ongoing experiment to transition away from
`std.event.Group` in favor of `std.event.Batch`.
* `std.os.execvpeC` calls `getenvZ` rather than `getenv`. This is
slightly more efficient on most systems, and works around a
limitation of `getenv` lack of integration with libc.
* (breaking) `std.os.AccessError` gains `FileBusy`, `SymLinkLoop`, and
`ReadOnlyFileSystem`. Previously these error codes were all reported
as `PermissionDenied`.
* Add `std.Target.isDragonFlyBSD`.
* stage2: access to the windows_sdk functions is done with a manually
maintained .zig binding file instead of `@cImport`.
* Update src-self-hosted/libc_installation.zig with all the
improvements that stage1 has seen to src/libc_installation.cpp until
now. In addition, it now takes advantage of Batch so that evented I/O
mode takes advantage of concurrency, but it still works in blocking
I/O mode, which is how it is used in stage1.
1. behavior tests with --test-evented-io
2. std lib tests with --test-evented-io
3. fuzz test evented I/O a bit, make it robust
4. make sure it works on all platforms (kqueue, Windows IOCP,
epoll/other)
5. restart efforts on self-hosted
Previously it was a tagged union which was one of:
* baseline
* a specific CPU
* a set of features
Now, it's possible to have a CPU but also modify the CPU's feature set
on top of that. This is closer to what LLVM does.
This is more correct because Zig's notion of CPUs (and LLVM's) is not
exact CPU models. For example "skylake" is not one very specific model;
there are several different pieces of hardware that match "skylake" that
have different feature sets enabled.
comment from this commit reproduced here:
I have observed the CPU name reported by LLVM being incorrect. On
the SourceHut build services, LLVM 9.0 reports the CPU as "athlon-xp",
which is a 32-bit CPU, even though the system is 64-bit and the reported
CPU features include, among other things, +64bit.
So the strategy taken here is that we observe both reported CPU, and the
reported CPU features. The features are trusted more; but if the features
match exactly the features of the reported CPU, then we trust the reported CPU.
Andrew Kelley
Michael Dusan
Vexu
Michaël Larouche
LemonBoy
Benjamin Feng
Feix Weiglhofer