bjoernager/rust
bjoernager/rust
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Clarify some cleanup stuff.

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- Rearrange the match in `llbb_with_landing_pad` so the `(Some,Some)`
  cases are together.
- Add assertions to indicate two MSVC-only paths.
This commit is contained in:
Nicholas Nethercote 2022-10-19 10:59:02 +11:00
parent a5bd5da594
commit 03f350f5a5
1 changed files with 10 additions and 6 deletions
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16
compiler/rustc_codegen_ssa/src/mir/block.rs
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@ -75,13 +75,16 @@ impl<'a, 'tcx> TerminatorCodegenHelper<'tcx> {
let target_funclet = fx.cleanup_kinds[target].funclet_bb(target); let target_funclet = fx.cleanup_kinds[target].funclet_bb(target);
match (self.funclet_bb, target_funclet) { match (self.funclet_bb, target_funclet) {
(None, None) => (lltarget, false), (None, None) => (lltarget, false),
(Some(f), Some(t_f)) if f == t_f || !base::wants_msvc_seh(fx.cx.tcx().sess) => {
(lltarget, false)
}
// jump *into* cleanup - need a landing pad if GNU, cleanup pad if MSVC // jump *into* cleanup - need a landing pad if GNU, cleanup pad if MSVC
(None, Some(_)) => (fx.landing_pad_for(target), false), (None, Some(_)) => (fx.landing_pad_for(target), false),
(Some(_), None) => span_bug!(span, "{:?} - jump out of cleanup?", self.terminator), (Some(_), None) => span_bug!(span, "{:?} - jump out of cleanup?", self.terminator),
(Some(_), Some(_)) => (fx.landing_pad_for(target), true), (Some(f), Some(t_f)) => {
if f == t_f || !base::wants_msvc_seh(fx.cx.tcx().sess) {
(lltarget, false)
} else {
(fx.landing_pad_for(target), true)
}
}
} }
} }
@ -95,7 +98,7 @@ impl<'a, 'tcx> TerminatorCodegenHelper<'tcx> {
let (lltarget, is_cleanupret) = self.llbb_with_landing_pad(fx, target); let (lltarget, is_cleanupret) = self.llbb_with_landing_pad(fx, target);
if is_cleanupret { if is_cleanupret {
// MSVC cross-funclet jump - need a trampoline // MSVC cross-funclet jump - need a trampoline
debug_assert!(base::wants_msvc_seh(fx.cx.tcx().sess));
debug!("llbb_with_cleanup: creating cleanup trampoline for {:?}", target); debug!("llbb_with_cleanup: creating cleanup trampoline for {:?}", target);
let name = &format!("{:?}_cleanup_trampoline_{:?}", self.bb, target); let name = &format!("{:?}_cleanup_trampoline_{:?}", self.bb, target);
let trampoline_llbb = Bx::append_block(fx.cx, fx.llfn, name); let trampoline_llbb = Bx::append_block(fx.cx, fx.llfn, name);
@ -115,8 +118,9 @@ impl<'a, 'tcx> TerminatorCodegenHelper<'tcx> {
) { ) {
let (lltarget, is_cleanupret) = self.llbb_with_landing_pad(fx, target); let (lltarget, is_cleanupret) = self.llbb_with_landing_pad(fx, target);
if is_cleanupret { if is_cleanupret {
// micro-optimization: generate a `ret` rather than a jump // MSVC micro-optimization: generate a `ret` rather than a jump
// to a trampoline. // to a trampoline.
debug_assert!(base::wants_msvc_seh(fx.cx.tcx().sess));
bx.cleanup_ret(self.funclet(fx).unwrap(), Some(lltarget)); bx.cleanup_ret(self.funclet(fx).unwrap(), Some(lltarget));
} else { } else {
bx.br(lltarget); bx.br(lltarget);