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Error out when repr(align) exceeds COFF limit
The PE-COFF binary format limits section alignment to 8192 bytes. Emit error when alignment exceeds this limit to avoid crash in llvm.
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-18
lines changed

8 files changed

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‎compiler/rustc_error_codes/src/error_codes/E0806.md‎

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The value of `N` that was specified for `repr(align(N))` was greater than the
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PE-COFF limit (8192 bytes).
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Erroneous code example:
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```ignore (fails only on PE-COFF targets)
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#[repr(align(16384))] // error: alignment must not be greater than 8192 bytes
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// for COFF targets
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enum Foo {
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Bar(u64),
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}
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```

‎compiler/rustc_error_codes/src/lib.rs‎

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@@ -545,6 +545,7 @@ E0802: 0802,
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E0803: 0803,
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E0804: 0804,
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E0805: 0805,
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E0806: 0806,
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);
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)
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}

‎compiler/rustc_passes/messages.ftl‎

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@@ -481,6 +481,9 @@ passes_remove_fields =
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*[other] fields
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}
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passes_repr_align_greater_than_coff_max =
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alignment must not be greater than 8192 bytes for COFF targets
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passes_repr_align_greater_than_target_max =
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alignment must not be greater than `isize::MAX` bytes
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.note = `isize::MAX` is {$size} for the current target

‎compiler/rustc_passes/src/check_attr.rs‎

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@@ -44,13 +44,18 @@ use rustc_session::lint::builtin::{
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use rustc_session::parse::feature_err;
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use rustc_span::edition::Edition;
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use rustc_span::{BytePos, DUMMY_SP, Span, Symbol, edition, sym};
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use rustc_target::spec::BinaryFormat;
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use rustc_trait_selection::error_reporting::InferCtxtErrorExt;
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use rustc_trait_selection::infer::{TyCtxtInferExt, ValuePairs};
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use rustc_trait_selection::traits::ObligationCtxt;
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use tracing::debug;
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use crate::{errors, fluent_generated as fluent};
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// Max alignment supported for PE-COFF binary format.
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// See https://learn.microsoft.com/en-us/cpp/cpp/align-cpp?view=msvc-170
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const COFF_MAX_ALIGN_BYTES: u64 = 0x2000;
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#[derive(LintDiagnostic)]
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#[diag(passes_diagnostic_diagnostic_on_unimplemented_only_for_traits)]
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struct DiagnosticOnUnimplementedOnlyForTraits;
@@ -1805,6 +1810,12 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
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}
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fn check_align(&self, align: Align, span: Span) {
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if self.tcx.sess.target.binary_format == BinaryFormat::Coff {
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if align.bytes() > COFF_MAX_ALIGN_BYTES {
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self.dcx().emit_err(errors::InvalidReprAlignForCoff { span });
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}
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}
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if align.bytes() > 2_u64.pow(29) {
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// for values greater than 2^29, a different error will be emitted, make sure that happens
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self.dcx().span_delayed_bug(

‎compiler/rustc_passes/src/errors.rs‎

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@@ -478,6 +478,13 @@ pub(crate) struct InvalidReprAlignForTarget {
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pub size: u64,
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}
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#[derive(Diagnostic)]
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#[diag(passes_repr_align_greater_than_coff_max, code = E0806)]
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pub(crate) struct InvalidReprAlignForCoff {
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#[primary_span]
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pub span: Span,
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}
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#[derive(LintDiagnostic)]
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#[diag(passes_repr_conflicting, code = E0566)]
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pub(crate) struct ReprConflictingLint;

‎tests/ui/repr/repr-align.stderr‎ renamed to ‎tests/ui/repr/repr-align.notwin.stderr‎

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@@ -1,47 +1,47 @@
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error[E0589]: invalid `repr(align)` attribute: not an unsuffixed integer
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--> $DIR/repr-align.rs:3:14
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--> $DIR/repr-align.rs:14:14
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|
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LL | #[repr(align(16.0))]
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| ^^^^
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error[E0589]: invalid `repr(align)` attribute: not a power of two
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--> $DIR/repr-align.rs:6:14
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--> $DIR/repr-align.rs:17:14
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|
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LL | #[repr(align(15))]
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| ^^
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error[E0589]: invalid `repr(align)` attribute: larger than 2^29
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--> $DIR/repr-align.rs:9:14
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--> $DIR/repr-align.rs:20:14
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|
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LL | #[repr(align(4294967296))]
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| ^^^^^^^^^^
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error[E0589]: invalid `repr(align)` attribute: not a power of two
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--> $DIR/repr-align.rs:15:14
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--> $DIR/repr-align.rs:27:14
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|
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LL | #[repr(align(0))]
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| ^
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error[E0589]: invalid `repr(align)` attribute: not an unsuffixed integer
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--> $DIR/repr-align.rs:18:14
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--> $DIR/repr-align.rs:33:14
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|
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LL | #[repr(align(16.0))]
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| ^^^^
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error[E0589]: invalid `repr(align)` attribute: not a power of two
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--> $DIR/repr-align.rs:21:14
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--> $DIR/repr-align.rs:36:14
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|
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LL | #[repr(align(15))]
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| ^^
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error[E0589]: invalid `repr(align)` attribute: larger than 2^29
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--> $DIR/repr-align.rs:24:14
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--> $DIR/repr-align.rs:39:14
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|
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LL | #[repr(align(4294967296))]
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| ^^^^^^^^^^
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error[E0589]: invalid `repr(align)` attribute: not a power of two
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--> $DIR/repr-align.rs:30:14
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--> $DIR/repr-align.rs:46:14
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|
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LL | #[repr(align(0))]
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| ^

‎tests/ui/repr/repr-align.rs‎

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@@ -1,33 +1,52 @@
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//@ revisions: win notwin
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//@ add-minicore
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//@ [win] compile-flags: --target x86_64-pc-windows-msvc
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//@ [win] needs-llvm-components: x86
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//@ [notwin] compile-flags: --target x86_64-unknown-linux-gnu
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//@ [notwin] needs-llvm-components: x86
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#![feature(no_core, lang_items)]
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#![no_core]
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#![allow(dead_code)]
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extern crate minicore;
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use minicore::*;
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#[repr(align(16.0))] //~ ERROR: invalid `repr(align)` attribute: not an unsuffixed integer
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#[repr(align(16.0))] //[notwin,win]~ ERROR: invalid `repr(align)` attribute: not an unsuffixed integer
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struct S0(i32);
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#[repr(align(15))] //~ ERROR: invalid `repr(align)` attribute: not a power of two
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#[repr(align(15))] //[notwin,win]~ ERROR: invalid `repr(align)` attribute: not a power of two
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struct S1(i32);
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#[repr(align(4294967296))] //~ ERROR: invalid `repr(align)` attribute: larger than 2^29
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#[repr(align(4294967296))] //[notwin,win]~ ERROR: invalid `repr(align)` attribute: larger than 2^29
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struct S2(i32);
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#[repr(align(536870912))] // ok: this is the largest accepted alignment
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#[repr(align(536870912))] //[win]~ ERROR: alignment must not be greater than 8192 bytes for COFF targets
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// notwin: this is the largest accepted alignment
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struct S3(i32);
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#[repr(align(0))] //~ ERROR: invalid `repr(align)` attribute: not a power of two
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#[repr(align(0))] //[notwin,win]~ ERROR: invalid `repr(align)` attribute: not a power of two
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struct S4(i32);
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#[repr(align(16.0))] //~ ERROR: invalid `repr(align)` attribute: not an unsuffixed integer
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#[repr(align(16384))] //[win]~ ERROR: alignment must not be greater than 8192 bytes for COFF targets
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struct S5(i32);
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#[repr(align(16.0))] //[notwin,win]~ ERROR: invalid `repr(align)` attribute: not an unsuffixed integer
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enum E0 { A, B }
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#[repr(align(15))] //~ ERROR: invalid `repr(align)` attribute: not a power of two
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#[repr(align(15))] //[notwin,win]~ ERROR: invalid `repr(align)` attribute: not a power of two
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enum E1 { A, B }
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#[repr(align(4294967296))] //~ ERROR: invalid `repr(align)` attribute: larger than 2^29
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#[repr(align(4294967296))] //[notwin,win]~ ERROR: invalid `repr(align)` attribute: larger than 2^29
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enum E2 { A, B }
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#[repr(align(536870912))] // ok: this is the largest accepted alignment
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#[repr(align(536870912))] //[win]~ ERROR: alignment must not be greater than 8192 bytes for COFF targets
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// notwin: this is the largest accepted alignment
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enum E3 { A, B }
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#[repr(align(0))] //~ ERROR: invalid `repr(align)` attribute: not a power of two
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#[repr(align(0))] //[notwin,win]~ ERROR: invalid `repr(align)` attribute: not a power of two
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enum E4 { A, B }
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#[repr(align(16384))] //[win]~ ERROR: alignment must not be greater than 8192 bytes for COFF targets
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enum E5 { A, B }
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fn main() {}

‎tests/ui/repr/repr-align.win.stderr‎

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error[E0589]: invalid `repr(align)` attribute: not an unsuffixed integer
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--> $DIR/repr-align.rs:14:14
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|
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LL | #[repr(align(16.0))]
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| ^^^^
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error[E0589]: invalid `repr(align)` attribute: not a power of two
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--> $DIR/repr-align.rs:17:14
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|
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LL | #[repr(align(15))]
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| ^^
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error[E0589]: invalid `repr(align)` attribute: larger than 2^29
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--> $DIR/repr-align.rs:20:14
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|
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LL | #[repr(align(4294967296))]
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| ^^^^^^^^^^
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error[E0589]: invalid `repr(align)` attribute: not a power of two
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--> $DIR/repr-align.rs:27:14
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|
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LL | #[repr(align(0))]
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| ^
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error[E0589]: invalid `repr(align)` attribute: not an unsuffixed integer
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--> $DIR/repr-align.rs:33:14
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|
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LL | #[repr(align(16.0))]
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| ^^^^
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error[E0589]: invalid `repr(align)` attribute: not a power of two
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--> $DIR/repr-align.rs:36:14
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|
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LL | #[repr(align(15))]
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| ^^
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error[E0589]: invalid `repr(align)` attribute: larger than 2^29
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--> $DIR/repr-align.rs:39:14
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|
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LL | #[repr(align(4294967296))]
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| ^^^^^^^^^^
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error[E0589]: invalid `repr(align)` attribute: not a power of two
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--> $DIR/repr-align.rs:46:14
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|
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LL | #[repr(align(0))]
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| ^
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error[E0806]: alignment must not be greater than 8192 bytes for COFF targets
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--> $DIR/repr-align.rs:23:8
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|
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LL | #[repr(align(536870912))]
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| ^^^^^^^^^^^^^^^^
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error[E0806]: alignment must not be greater than 8192 bytes for COFF targets
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--> $DIR/repr-align.rs:30:8
57+
|
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LL | #[repr(align(16384))]
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| ^^^^^^^^^^^^
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error[E0806]: alignment must not be greater than 8192 bytes for COFF targets
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--> $DIR/repr-align.rs:42:8
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|
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LL | #[repr(align(536870912))]
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| ^^^^^^^^^^^^^^^^
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error[E0806]: alignment must not be greater than 8192 bytes for COFF targets
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--> $DIR/repr-align.rs:49:8
69+
|
70+
LL | #[repr(align(16384))]
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| ^^^^^^^^^^^^
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error: aborting due to 12 previous errors
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Some errors have detailed explanations: E0589, E0806.
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For more information about an error, try `rustc --explain E0589`.

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