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rustc_const_eval: respect target.min_global_align #142198

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rustc_const_eval: respect target.min_global_align #142198

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5 changes: 4 additions & 1 deletion compiler/rustc_const_eval/src/interpret/memory.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -893,7 +893,10 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {

// # Global allocations
if let Some(global_alloc) = self.tcx.try_get_global_alloc(id) {
let (size, align) = global_alloc.size_and_align(*self.tcx, self.typing_env);
let (size, mut align) = global_alloc.size_and_align(*self.tcx, self.typing_env);
if let Some(min_global_align) = self.tcx.sess.target.min_global_align {
align = Ord::max(align, min_global_align);
}
let mutbl = global_alloc.mutability(*self.tcx, self.typing_env);
let kind = match global_alloc {
GlobalAlloc::Static { .. } | GlobalAlloc::Memory { .. } => AllocKind::LiveData,
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37 changes: 37 additions & 0 deletions src/tools/miri/tests/pass/static_align.rs
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Any chance this could be done with a macro rather than having to repeat the same code many times?

Original file line number Diff line number Diff line change
@@ -0,0 +1,37 @@
// Test that miri respects the `target.min_global_align` value for the target.
//
// The only way to observe its effect currently is to test for the alignment of statics with a
// natural alignment of 1 on s390x. On that target, the `min_global_align` is 2 bytes.

fn main() {
let min_align = if cfg!(target_arch = "s390x") { 2 } else { 1 };

macro_rules! check {
($x:ident, $v:expr) => {
static $x: bool = $v;
assert!(core::ptr::from_ref(&$x).addr().is_multiple_of(min_align));
};
}

check!(T0, true);
check!(T1, true);
check!(T2, true);
check!(T3, true);
check!(T4, true);
check!(T5, true);
check!(T6, true);
check!(T7, true);
check!(T8, true);
check!(T9, true);

check!(F0, false);
check!(F1, false);
check!(F2, false);
check!(F3, false);
check!(F4, false);
check!(F5, false);
check!(F6, false);
check!(F7, false);
check!(F8, false);
check!(F9, false);
}
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