The new representation is often more compact. It is also more
straightforward to understand: for instance, `extern` is represented on
the `declaration` instruction itself rather than using a special
instruction. The same applies to `var`, making both of these far more
compact.
This commit also separates the type and value bodies of a `declaration`
instruction. This is a prerequisite for #131.
In general, `declaration` now directly encodes details of the syntax
form used, and the embedded ZIR bodies are for actual expressions. The
only exception to this is functions, where ZIR is effectively designed
as if we had #1717. `extern fn` declarations are modeled as
`extern const` with a function type, and normal `fn` definitions are
modeled as `const` with a `func{,_fancy,_inferred}` instruction. This
may change in the future, but improving on this was out of scope for
this commit.
looking at `man getgroups` and `info getgroups` this is given as an
example:
```c
// Here's how to use ‘getgroups’ to read all the supplementary group
// IDs:
gid_t *
read_all_groups (void)
{
int ngroups = getgroups (0, NULL);
gid_t *groups
= (gid_t *) xmalloc (ngroups * sizeof (gid_t));
int val = getgroups (ngroups, groups);
if (val < 0)
{
free (groups);
return NULL;
}
return groups;
}
```
getgroups(0, NULL) is used to get the count of groups so that the
correct count can be used to allocate a list of gid_t. This small changes makes this
possible.
equivalent example in Zig after the change:
```zig
// get the group count
const ngroups: usize = std.os.linux.getgroups(0, null);
if (ngroups <= 0) {
return error.GetGroupsError;
}
std.debug.print("number of groups: {d}\n", .{ngroups});
const groups_gids: []u32 = try alloc.alloc(u32, ngroups);
// populate an array of gid_t
_ = std.os.linux.getgroups(ngroups, @ptrCast(groups_gids));
```
This commit amends `std.Build.ExecutableOptions` etc to have a new
field, `root_module`, which allows artifacts to be created whose root
module is an existing `*Module` rather than a freshly constructed one.
This API can be far more versatile, allowing construction of complex
module graphs before creating any compile steps, and therefore also
allowing easy reuse of modules.
The fields which correspond to module options, such as
`root_source_file`, are all considered deprecated. They may not be
populated at the same time as the `root_module` field. In the next
release cycle, these deprecated fields will be removed, and the
`root_module` field made non-optional.
At the expense of a slight special case in the build runner, we can make
the handling of dependencies between modules a little shorter and much
easier to follow.
When module and step graphs are being constructed during the "configure"
phase, we do not set up step dependencies triggered by modules. Instead,
after the configure phase, the build runner traverses the whole
step/module graph, starting from the root top-level steps, and
configures all step dependencies implied by modules. The "make" phase
then proceeds as normal. Also, the old `Module.dependencyIterator` logic
is replaced by two separate iterables. `Module.getGraph` takes the root
module of a compilation, and returns all modules in its graph; while
`Step.Compile.getCompileDependencies` takes a `*Step.Compile` and
returns all `*Step.Compile` it depends on, recursively, possibly
excluding dynamic libraries. The old `Module.dependencyIterator`
combined these two functions into one unintuitive iterator; they are now
separated, which in particular helps readability at the usage sites
which only need one or the other.
This commit changes the `root_module` field of `std.Build.Step.Compile`
to be a `*Module` rather than a `Module`. This is a breaking change, but
an incredibly minor one (the full potential extent of the breakage can
be seen in the modified standalone test).
This change will be necessary for an upcoming improvement, so it was
convenient to make it here.
(With the exception of x86 since that was available from the beginning.)
These were determined by analyzing the full, reconstructed Git history of the
Linux kernel here: https://landley.net/kdocs/fullhist
Currently, `zig ast-check` fails on ZON files, because it tries to
interpret the file as Zig source code. This commit introduces a new
verification pass, `std.zig.ZonGen`, which applies to an AST in ZON
mode.
Like `AstGen`, this pass also converts the AST into a more helpful
format. Rather than a sequence of instructions like `Zir`, the output
format of `ZonGen` is a new datastructure called `Zoir`. This type is
essentially a simpler form of AST, containing only the information
required for consumers of ZON. It is also far more compact than
`std.zig.Ast`, with the size generally being comparable to the size of
the well-formatted source file.
The emitted `Zoir` is currently not used aside from the `-t` option to
`ast-check` which causes it to be dumped to stdout. However, in future,
it can be used for comptime `@import` of ZON files, as well as for
simpler handling of files like `build.zig.zon`, and even by other parts
of the Zig Standard Library.
Resolves: #22078
This code was left over from the legacy Autodoc implementation. No
component of the compiler pipeline actually requires doc comments, so it
is a waste of time and space to store them in ZIR.
This is, at least today, a very broken target: It doesn't actually build either
musl or wasi-libc even if you use -lc. It does give you musl headers, but that's
it. Those headers are not terribly useful, however, without any implementation
code. You can sort of call some math functions because they just so happen to
have implementations in compiler-rt. But that's only true for a small subset,
and I don't think users should be relying on the ABI surface of a library that
is an implementation detail of the compiler.
Clearly, a freestanding-capable libc of sorts is a useful thing as evidenced by
newlib, picolibc, etc existing. However, calling it "musl" is misleading when it
isn't actually musl-compatible, nor can it ever be because the musl API surface
is inextricably tied to the Linux kernel. In the discussion on #20690, there was
agreement that once we split up the API and ABI components in the target string,
the API component should be about compatibility, not whether you literally get a
particular implementation of it. Also, we decided that Linux musl and wasi-libc
musl shouldn't use the same API tag precisely because they're not actually
compatible.
(And besides, how would any syscall even be implemented in freestanding? Who or
what would we be calling?)
So I think we should remove this triple for now. If we decide to reintroduce
something like this, especially once #2879 gets going, we should come up with a
bespoke name for it rather than using "musl".
In cf88cf2657d721c68055a284e8c498a18639f74c the eql function provided in
The context of ArrayHashMap was changed to also include the key index,
but this wasn't properly updated in the documentation.
Since a flat `usize` is unintuitive, I've tried to explain the function
of the parameter as best I can based on the original commit.
Finally, I didn't do an extensive search if this eql definition is
incorrectly stated anywhere outside of these 2 spots. But I somewhat
doubt an file outside of `array_hash_map` would
The previous commit cast doubt upon the initial report about macOS
kernel behavior, identifying another reason that ENOENT could be
returned from file creation.
However, it is demonstrable that ENOENT can be returned for both cases:
1. create file race
2. handle refers to deleted directory
This commit re-introduces the workaround for the file creation race on
macOS however it does not unconditionally retry - it first tries again
with O_EXCL to disambiguate the error condition that has occurred.
Previous commits
2b0929929d67e222ca6a9523a3a594ed456c4a51
4ea2f441df36cec61e1017f4d795d4037326c98c
had this text:
> There are no dir components, so you would think that this was
> unreachable, however we have observed on macOS two processes racing to
> do openat() with O_CREAT manifest in ENOENT.
This appears to have been a misunderstanding based on the issue
report #12138 and corresponding PR #12139 in which the steps to
reproduce removed the cache directory in a loop which also executed
detached Zig compiler processes.
There is no evidence for the macOS kernel bug however the ENOENT is
easily explained by the removal of the cache directory.
This commit reverts those commits, ultimately reporting the ENOENT as an
error rather than repeating the create file operation. However this
commit also adds an explicit error set to `std.Build.Cache.hit` as well
as changing the `failed_file_index` to a proper diagnostic field that
fully communicates what failed, leading to more informative error
messages on failure to check the cache.
The equivalent failure when occuring for AstGen performs a fatal process
kill, reasoning being that the compiler has an invariant of the cache
directory not being yanked out from underneath it while executing. This
could be made a more granular error in the future but I suspect such
thing is not valuable to pursue.
Related to #18340 but does not solve it.
Whatever was in the frame pointer register prior to clone() will no longer be
valid in the child process, so zero it to protect FP-based unwinders. Similarly,
mark the link register as undefined to protect DWARF-based unwinders.
This is only zeroing the frame pointer(s) on Arm/Thumb because of an LLVM
assembler bug: https://github.com/llvm/llvm-project/issues/115891
