Rollup merge of #129897 - RalfJung:soft-float-ignored, r=Urgau

deprecate -Csoft-float because it is unsound (and not fixable)

See  https://github.com/rust-lang/rust/issues/129893 for details. The general sentiment there seems to be that this flag has no use and sound alternatives exist, so let's add this warning and see if anyone out there disagrees.

Also show a different warning on targets where it does nothing (as documented since https://github.com/rust-lang/rust/pull/36261): it seems to correspond to `-mfloat-abi` in GCC/clang, which is an ARM-specific option. To be really sure it does nothing, only forward the flag to LLVM for eabihf targets. This should not change behavior but makes me sleep better ;)

1 files changed, 11 insertions, 0 deletions

diff --git a/compiler/rustc_session/src/errors.rs b/compiler/rustc_session/src/errors.rs
index 462e2a97c33..dbb74d1e244 100644
--- a/compiler/rustc_session/src/errors.rs
+++ b/compiler/rustc_session/src/errors.rs
@@ -490,3 +490,14 @@ pub(crate) struct FunctionReturnThunkExternRequiresNonLargeCodeModel;
 pub(crate) struct FailedToCreateProfiler {
     pub(crate) err: String,
 }
+
+#[derive(Diagnostic)]
+#[diag(session_soft_float_ignored)]
+#[note]
+pub(crate) struct SoftFloatIgnored;
+
+#[derive(Diagnostic)]
+#[diag(session_soft_float_deprecated)]
+#[note]
+#[note(session_soft_float_deprecated_issue)]
+pub(crate) struct SoftFloatDeprecated;