diff options
| -rw-r--r-- | compiler/rustc_codegen_llvm/src/attributes.rs | 15 | ||||
| -rw-r--r-- | compiler/rustc_session/src/session.rs | 9 |
2 files changed, 8 insertions, 16 deletions
diff --git a/compiler/rustc_codegen_llvm/src/attributes.rs b/compiler/rustc_codegen_llvm/src/attributes.rs index 5a065f31c30..1ea5a062254 100644 --- a/compiler/rustc_codegen_llvm/src/attributes.rs +++ b/compiler/rustc_codegen_llvm/src/attributes.rs @@ -370,21 +370,6 @@ pub(crate) fn llfn_attrs_from_instance<'ll, 'tcx>( }; to_add.extend(inline_attr(cx, inline)); - // The `uwtable` attribute according to LLVM is: - // - // This attribute indicates that the ABI being targeted requires that an - // unwind table entry be produced for this function even if we can show - // that no exceptions passes by it. This is normally the case for the - // ELF x86-64 abi, but it can be disabled for some compilation units. - // - // Typically when we're compiling with `-C panic=abort` we don't need - // `uwtable` because we can't generate any exceptions! On Windows, however, - // exceptions include other events such as illegal instructions, segfaults, - // etc. This means that on Windows we end up still needing the `uwtable` - // attribute even if the `-C panic=abort` flag is passed. - // - // You can also find more info on why Windows always requires uwtables here: - // https://bugzilla.mozilla.org/show_bug.cgi?id=1302078 if cx.sess().must_emit_unwind_tables() { to_add.push(uwtable_attr(cx.llcx, cx.sess().opts.unstable_opts.use_sync_unwind)); } diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs index 8386fe8dab0..85bd8340c3c 100644 --- a/compiler/rustc_session/src/session.rs +++ b/compiler/rustc_session/src/session.rs @@ -776,8 +776,15 @@ impl Session { pub fn must_emit_unwind_tables(&self) -> bool { // This is used to control the emission of the `uwtable` attribute on - // LLVM functions. + // LLVM functions. The `uwtable` attribute according to LLVM is: // + // This attribute indicates that the ABI being targeted requires that an + // unwind table entry be produced for this function even if we can show + // that no exceptions passes by it. This is normally the case for the + // ELF x86-64 abi, but it can be disabled for some compilation units. + // + // Typically when we're compiling with `-C panic=abort` we don't need + // `uwtable` because we can't generate any exceptions! // Unwind tables are needed when compiling with `-C panic=unwind`, but // LLVM won't omit unwind tables unless the function is also marked as // `nounwind`, so users are allowed to disable `uwtable` emission. |