Rollup merge of #144706 - zachs18:fix-144661, r=RalfJung

Do not give function allocations alignment in consteval and Miri.

We do not yet have a (clear and T-lang approved) design for how `#[align(N)]` on functions should affect function pointers' addresses on various platforms, so for now do not give function pointers alignment in consteval and Miri.

----

Old summary:

Not a full solution to <https://github.com/rust-lang/rust/issues/144661>, but fixes the immediate issue by making function allocations all have alignment 1 in consteval, ignoring `#[rustc_align(N)]`, so the compiler doesn't know if any offset other than 0 is non-null.

A more "principlied" solution would probably be to make function pointers to `#[instruction_set(arm::t32)]` functions be at offset 1 of an align-`max(2, align attribute)` allocation instead of at offset 0 of their allocation during consteval, and on wasm to either disallow `#[align(N)]` where N > 1, or to pad the function table such that the function pointer of a `#[align(N)]` function is a multiple of `N` at runtime.

1 files changed, 0 insertions, 25 deletions

diff --git a/src/tools/miri/tests/pass/fn_align.rs b/src/tools/miri/tests/pass/fn_align.rs
deleted file mode 100644
index 9752d033458..00000000000
--- a/src/tools/miri/tests/pass/fn_align.rs
+++ /dev/null
@@ -1,25 +0,0 @@
-//@compile-flags: -Zmin-function-alignment=8
-
-// FIXME(rust-lang/rust#82232, rust-lang/rust#143834): temporarily renamed to mitigate `#[align]`
-// nameres ambiguity
-#![feature(rustc_attrs)]
-#![feature(fn_align)]
-
-// When a function uses `align(N)`, the function address should be a multiple of `N`.
-
-#[rustc_align(256)]
-fn foo() {}
-
-#[rustc_align(16)]
-fn bar() {}
-
-#[rustc_align(4)]
-fn baz() {}
-
-fn main() {
-    assert!((foo as usize).is_multiple_of(256));
-    assert!((bar as usize).is_multiple_of(16));
-
-    // The maximum of `align(N)` and `-Zmin-function-alignment=N` is used.
-    assert!((baz as usize).is_multiple_of(8));
-}