diff options
Diffstat (limited to 'compiler/rustc_codegen_ssa/src')
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/mir/block.rs | 73 | ||||
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/traits/builder.rs | 12 |
2 files changed, 74 insertions, 11 deletions
diff --git a/compiler/rustc_codegen_ssa/src/mir/block.rs b/compiler/rustc_codegen_ssa/src/mir/block.rs index bde63fd501a..e96590441fa 100644 --- a/compiler/rustc_codegen_ssa/src/mir/block.rs +++ b/compiler/rustc_codegen_ssa/src/mir/block.rs @@ -35,6 +35,14 @@ enum MergingSucc { True, } +/// Indicates to the call terminator codegen whether a cal +/// is a normal call or an explicit tail call. +#[derive(Debug, PartialEq)] +enum CallKind { + Normal, + Tail, +} + /// Used by `FunctionCx::codegen_terminator` for emitting common patterns /// e.g., creating a basic block, calling a function, etc. struct TerminatorCodegenHelper<'tcx> { @@ -160,6 +168,7 @@ impl<'a, 'tcx> TerminatorCodegenHelper<'tcx> { mut unwind: mir::UnwindAction, lifetime_ends_after_call: &[(Bx::Value, Size)], instance: Option<Instance<'tcx>>, + kind: CallKind, mergeable_succ: bool, ) -> MergingSucc { let tcx = bx.tcx(); @@ -221,6 +230,11 @@ impl<'a, 'tcx> TerminatorCodegenHelper<'tcx> { } }; + if kind == CallKind::Tail { + bx.tail_call(fn_ty, fn_attrs, fn_abi, fn_ptr, llargs, self.funclet(fx), instance); + return MergingSucc::False; + } + if let Some(unwind_block) = unwind_block { let ret_llbb = if let Some((_, target)) = destination { fx.llbb(target) @@ -659,6 +673,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> { unwind, &[], Some(drop_instance), + CallKind::Normal, !maybe_null && mergeable_succ, ) } @@ -747,8 +762,19 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> { let (fn_abi, llfn, instance) = common::build_langcall(bx, span, lang_item); // Codegen the actual panic invoke/call. - let merging_succ = - helper.do_call(self, bx, fn_abi, llfn, &args, None, unwind, &[], Some(instance), false); + let merging_succ = helper.do_call( + self, + bx, + fn_abi, + llfn, + &args, + None, + unwind, + &[], + Some(instance), + CallKind::Normal, + false, + ); assert_eq!(merging_succ, MergingSucc::False); MergingSucc::False } @@ -777,6 +803,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> { mir::UnwindAction::Unreachable, &[], Some(instance), + CallKind::Normal, false, ); assert_eq!(merging_succ, MergingSucc::False); @@ -845,6 +872,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> { unwind, &[], Some(instance), + CallKind::Normal, mergeable_succ, )) } @@ -860,6 +888,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> { target: Option<mir::BasicBlock>, unwind: mir::UnwindAction, fn_span: Span, + kind: CallKind, mergeable_succ: bool, ) -> MergingSucc { let source_info = mir::SourceInfo { span: fn_span, ..terminator.source_info }; @@ -1003,8 +1032,13 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> { // We still need to call `make_return_dest` even if there's no `target`, since // `fn_abi.ret` could be `PassMode::Indirect`, even if it is uninhabited, // and `make_return_dest` adds the return-place indirect pointer to `llargs`. - let return_dest = self.make_return_dest(bx, destination, &fn_abi.ret, &mut llargs); - let destination = target.map(|target| (return_dest, target)); + let destination = match kind { + CallKind::Normal => { + let return_dest = self.make_return_dest(bx, destination, &fn_abi.ret, &mut llargs); + target.map(|target| (return_dest, target)) + } + CallKind::Tail => None, + }; // Split the rust-call tupled arguments off. let (first_args, untuple) = if sig.abi() == ExternAbi::RustCall @@ -1020,6 +1054,14 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> { // to generate `lifetime_end` when the call returns. let mut lifetime_ends_after_call: Vec<(Bx::Value, Size)> = Vec::new(); 'make_args: for (i, arg) in first_args.iter().enumerate() { + if kind == CallKind::Tail && matches!(fn_abi.args[i].mode, PassMode::Indirect { .. }) { + // FIXME: https://github.com/rust-lang/rust/pull/144232#discussion_r2218543841 + span_bug!( + fn_span, + "arguments using PassMode::Indirect are currently not supported for tail calls" + ); + } + let mut op = self.codegen_operand(bx, &arg.node); if let (0, Some(ty::InstanceKind::Virtual(_, idx))) = (i, instance.map(|i| i.def)) { @@ -1147,6 +1189,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> { unwind, &lifetime_ends_after_call, instance, + kind, mergeable_succ, ) } @@ -1388,15 +1431,23 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> { target, unwind, fn_span, + CallKind::Normal, mergeable_succ(), ), - mir::TerminatorKind::TailCall { .. } => { - // FIXME(explicit_tail_calls): implement tail calls in ssa backend - span_bug!( - terminator.source_info.span, - "`TailCall` terminator is not yet supported by `rustc_codegen_ssa`" - ) - } + mir::TerminatorKind::TailCall { ref func, ref args, fn_span } => self + .codegen_call_terminator( + helper, + bx, + terminator, + func, + args, + mir::Place::from(mir::RETURN_PLACE), + None, + mir::UnwindAction::Unreachable, + fn_span, + CallKind::Tail, + mergeable_succ(), + ), mir::TerminatorKind::CoroutineDrop | mir::TerminatorKind::Yield { .. } => { bug!("coroutine ops in codegen") } diff --git a/compiler/rustc_codegen_ssa/src/traits/builder.rs b/compiler/rustc_codegen_ssa/src/traits/builder.rs index 979456a6ba7..4b18146863b 100644 --- a/compiler/rustc_codegen_ssa/src/traits/builder.rs +++ b/compiler/rustc_codegen_ssa/src/traits/builder.rs @@ -595,6 +595,18 @@ pub trait BuilderMethods<'a, 'tcx>: funclet: Option<&Self::Funclet>, instance: Option<Instance<'tcx>>, ) -> Self::Value; + + fn tail_call( + &mut self, + llty: Self::Type, + fn_attrs: Option<&CodegenFnAttrs>, + fn_abi: &FnAbi<'tcx, Ty<'tcx>>, + llfn: Self::Value, + args: &[Self::Value], + funclet: Option<&Self::Funclet>, + instance: Option<Instance<'tcx>>, + ); + fn zext(&mut self, val: Self::Value, dest_ty: Self::Type) -> Self::Value; fn apply_attrs_to_cleanup_callsite(&mut self, llret: Self::Value); |