All Zig code is eligible to `@import("builtin")` which is mapped to a
generated file, build.zig, based on the target and other settings.
Zig invocations which share the same target settings will generate the
same builtin.zig file and thus the path to builtin.zig is in a shared
cache folder, and different projects can sometimes use the same file.
Before this commit, this led to race conditions where multiple
invocations of `zig` would race to write this file. If one process
wanted to *read* the file while the other process *wrote* the file, the
reading process could observe a truncated or partially written
builtin.zig file.
This commit makes the following improvements:
- limitations:
- avoid clobbering the inode, mtime in the hot path
- avoid creating a partially written file
- builtin.zig needs to be on disk for debug info / stack trace purposes
- don't mark the task as complete until the file is finished being populated
(possibly by an external process)
- strategy:
- create the `@import("builtin")` `Module.File` during the AstGen
work, based on generating the contents in memory rather than
loading from disk.
- write builtin.zig in a separate task that doesn't have
to complete until the end of the AstGen work queue so that it
can be done in parallel with everything else.
- when writing the file, first stat the file path. If it exists, we are done.
- otherwise, write the file to a temp file in the same directory and atomically
rename it into place (clobbering the inode, mtime in the cold path).
- summary:
- all limitations respected
- hot path: one stat() syscall that happens in a worker thread
This required adding a missing function to the standard library:
`std.fs.Dir.statFile`. In this commit, it does open() and then fstat()
which is two syscalls. It should be improved in a future commit to only
make one.
Fixes#9439.
- Correctly load slice value on stack
- Implement WrapErrorUnionErr and payload
- Implement trunc, fix sliceLen and write undefined
- Implement slice as return type and argument
Note: This also fixes a memory leak for inferred error sets, and for usingnamespace
This reverts commit 725267f7c20f0ba588b472048a8c1fe1a328c714, reversing
changes made to 2dae860de3494f97c9477af9282fe0131ff5c4cb.
This test is failing:
```zig
pub fn main() u8 {
var e = foo();
const i = e catch 69;
return i;
}
fn foo() anyerror!u8 {
return 5;
}
```
It's returning 69 instead of the expected value 5.
This branch introduced std.Target.TargetAbi when we already had
std.Target.Abi which was, unsurprisingly, already suited for this task.
Also pull out the -mabi= cc flag addition to the common area instead of
duplicating it for assembly and c files.
The target abi can also be set in build.zig via LibExeObjStep.target_abi
The value passed in is checked that it is a valid value in
std.Target.TargetAbi
The target abi is also validated against the target cpu
`getExternalExecutor` is moved from `std.zig.CrossTarget` to
`std.zig.system.NativeTargetInfo.getExternalExecutor`.
The function also now communicates a bit more information about *why*
the host is unable to execute a binary. The CLI is updated to report
this information in a useful manner.
`getExternalExecutor` is also improved to detect such patterns as:
* x86_64 is able to execute x86 binaries
* aarch64 is able to execute arm binaries
* etc.
Added qemu-hexagon support to `getExternalExecutor`.
`std.Target.canExecBinaries` of is removed; callers should use the more
powerful `getExternalExecutor` instead.
Now that `zig test` tries to run the resulting binary no matter what,
this commit has a follow-up change to the build system and docgen to
utilize the `getExternalExecutor` function and pass `--test-no-exec`
in some cases to avoid getting the error.
Additionally:
* refactor: extract NativePaths and NativeTargetInfo into their own
files named after the structs.
* small improvement to langref to reduce the complexity of the `callconv`
expression in a couple examples.
Previously when using `zig run` or `zig test`, zig would try to guess
whether the host system was capable of running the target binaries. Now,
it will always try. If it fails, then Zig emits a helpful warning to
explain the probable cause.
from zig-specific options to generally recognized zig build options that
any project can take advantage of. See the updated usage text for more
details.
dd62a6d2e8de522187fd096354e7156cca1821c5 short-circuited the logic of
`asmExpr` by emitting ZIR for `@compileError("...")`. This caused false
positive "unreachable code" errors for stage1 when there was an
expression in the asm template.
This commit makes such cases instead go through logic of `asmExpr` like
normal, however the asm template is set to 0. This is then picked up in
Sema (part of stage2, not stage1) and reported as "assembly code must
use string literal syntax".
The end-game for inline assembly is that the syntax is more integrated
with zig, and it will not allow string concatenation for the assembler
code, for the same reasons that Zig does not have a preprocessor.
However, inline assembly in zig right now is lacking for a variety of
use cases (take a look at the open issues having to do with inline
assembly for example), and being able to use comptime expressions to
concatenate text is a workaround that real-world users are exploiting to
get by in the short term.
This commit keeps "assembly code must use string literal syntax" as a
compile error when using stage2, but allows it through when using
stage1.
I expect to revert this commit after making enough improvements to
inline assembly that our real world users' needs are satisfied.
Previously there was only `--single-threaded`.
This flag now matches other boolean flags, instead of only being able to
opt in to single-threaded builds, you can now force multi-threaded
builds. Currently this only has the possibility to emit an error
message, but it is a better user experience to understand why one cannot
choose to enable threads in some cases.
This is breaking change to the CLI.
Related: #10143
If a symbol is undefined after we tried resolving it in static and
dynamic libraries, and it is annotated with N_DESC_DISCARDED flag,
we simply ignore it rather than flagging an undefined symbol error.
* Add missing Linux headers. Closes#9837
* Update existing headers to latest Linux.
* Consolidate headers that are the same for multiple Zig target CPU
architectures. For example, Linux has only an x86 directory for both
x86_64 and x86 CPU architectures. Now Zig only ships an x86 directory
for Linux headers, and will emit the proper corresponding -isystem
flags.
* tools/update-linux-headers.zig is now available for upgrading to
newer Linux headers, and the update process is now documented on the
wiki.
