This commit moves the logic from `std.build.InstallRawStep` into `zig
objcopy`. The options here are limited, but we can add features as
needed.
closes#9261
New issues can be opened for specific objcopy flag support.
Originally I just wanted to move these down because they seemed to be in some random position of the file,
but these constants look very old with their CASING and pretty unnecessary anyway so I just inlined them.
This helps prevent errors related to undefined pointers being passed
through to some OS apis when slices have 0 length.
Tests have also been added to catch these cases.
The PCG32 fill function seems to have been copy-pasted from code using u64, so requesting `n` bytes where `(n & 7) > 4` bytes would cause the last few bytes to be all 0.
This implements `airSplat` for the native WebAssembly backend when
the features 'simd128' or 'relaxed-simd' are enabled. The commit
supports splat where the value lives in the linear memory segment,
as well as on the stack. This saves a lot of instruction cost.
When it detects the element type is not 8, 16, 32 or 64 bits,
the backend will instead use the same strategy as if the features
where disabled.
This adds the opcodes for both the simd128 and relaxed-simd features.
Those instructions are required by the self-hosted WebAssembly
backend. Additionally, this also adds the new `v128` Valtype which
is required to represent a 128bit simd value. SIMD values that do
not have exactly 128 bits will be represented differently.
This fixes a class of bugs on macOS where a segfault happening in
a loaded dylib with no debug info would cause a panic in the panic
handler instead of simply noting that the dylib has no valid debug
info via `error.MissingDebugInfo`. An example could be code linking
some system dylib and causing some routine to segfault on say invalid
pointer value, which should normally cause Zig to print an incomplete
stack trace anchored at the currently loaded image and backtrace all
the way back to the Zig binary with valid debug info. Currently, in
a situation like this we would trigger a panic within a panic.
On x86 interestingly I can see a reduction in codesize by 1 instruction with this.
While not necessarily faster, it might still reduce codesize a bit and this ordering is also more logical
because it follows ASCII table order. Rust's std uses this ordering too.
See https://zig.godbolt.org/z/PqodY8YqY for the difference.
This makes it so that we no longer use a LUT (Look-Up Table):
* The code is much simpler and easier to understand now.
* Using a LUT means we rely on a warm cache.
Relying on the cache like this results in inconsistent performance and in many cases codegen will be worse.
Also as @topolarity once pointed out, in some cases while it seems like the code may branch, it actually doesn't:
https://github.com/ziglang/zig/pull/11629#issuecomment-1213641429
* Other languages' standard libraries don't do this either.
JFF I wanted to see what other languages codegen compared to us now:
https://rust.godbolt.org/z/Te4ax9Edf, https://zig.godbolt.org/z/nTbYedWKv
So we are pretty much on par or better than other languages now.
* Improve and remove duplicate doNotOptimizeAway() implementations
We currently have two doNotOptimizeAway() implementations, one in
std.math and the other one in std.mem.
Maybe we should deprecate one. In the meantime, the std.math one
now just calls the std.mem one.
In a comptime environment, just ignore the value. Previously,
std.mem.doNotOptimizeAway() did not work at comptime.
If the value fits in a CPU register, just tell the compiler we
need that value to be computed, without clobbering anything else.
Only clobber all possibly escaped memory on pointers or large arrays.
Add tests by the way since we didn't had any (we had, but only
indirect ones).
- In #13720, expectEqualBytes was added as a standalone function
- In #13723, expectEqualSlices was made to use expectEqualBytes when the type was u8
- In this commit, expectEqualSlices has fully absorbed expectEqualBytes, and expectEqualBytes itself has been removed
For non-`u8` types, expectEqualSlices will now work similarly to expectEqualBytes (highlighting diffs in red), but will use a full line for each index and therefore will only print a maximum of 16 indexes.
