dawn-cmake/test/tint/array/assign_to_subexpr.wgsl.expected.msl
Ben Clayton f47887d207 tint/writer/msl: Generate an array<T,N> helper
And remove the WrapArraysInStructs transform.

Wrapping arrays in structures becomes troublesome for `const` arrays, as
currently WGSL does not allow `const` structures.

MSL 2.0+ has a builtin array<> helper, but we're targetting MSL 1.2, so
we have to emit our own. Fortunately, it can be done with a few lines of
templated code.

This produces significantly cleaner output.

Change-Id: Ifc92ef21e09befa252a07c856c4b5afdc51cc2e4
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/94540
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Ben Clayton <bclayton@chromium.org>
Reviewed-by: David Neto <dneto@google.com>
2022-06-24 17:01:59 +00:00

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#include <metal_stdlib>
using namespace metal;
template<typename T, size_t N>
struct tint_array {
const constant T& operator[](size_t i) const constant { return elements[i]; }
device T& operator[](size_t i) device { return elements[i]; }
const device T& operator[](size_t i) const device { return elements[i]; }
thread T& operator[](size_t i) thread { return elements[i]; }
const thread T& operator[](size_t i) const thread { return elements[i]; }
threadgroup T& operator[](size_t i) threadgroup { return elements[i]; }
const threadgroup T& operator[](size_t i) const threadgroup { return elements[i]; }
T elements[N];
};
struct S {
tint_array<int, 4> arr;
};
void foo() {
tint_array<int, 4> const src = tint_array<int, 4>{};
tint_array<int, 4> dst = {};
S dst_struct = {};
tint_array<tint_array<int, 4>, 2> dst_array = {};
dst_struct.arr = src;
dst_array[1] = src;
dst = src;
dst_struct.arr = src;
dst_array[0] = src;
}