Auto merge of #114993 - RalfJung:panic-nounwind, r=fee1-dead

interpret/miri: call the panic_nounwind machinery the same way codegen does

compiler/rustc_borrowck/src/invalidation.rs

@@ -159,7 +159,9 @@ impl<'cx, 'tcx> Visitor<'tcx> for InvalidationGenerator<'cx, 'tcx> {
 
                 self.mutate_place(location, *resume_arg, Deep);
             }
-            TerminatorKind::Resume | TerminatorKind::Return | TerminatorKind::GeneratorDrop => {
+            TerminatorKind::UnwindResume
+            | TerminatorKind::Return
+            | TerminatorKind::GeneratorDrop => {
                 // Invalidate all borrows of local places
                 let borrow_set = self.borrow_set;
                 let start = self.location_table.start_index(location);
@@ -200,7 +202,7 @@ impl<'cx, 'tcx> Visitor<'tcx> for InvalidationGenerator<'cx, 'tcx> {
                 }
             }
             TerminatorKind::Goto { target: _ }
-            | TerminatorKind::Terminate
+            | TerminatorKind::UnwindTerminate
             | TerminatorKind::Unreachable
             | TerminatorKind::FalseEdge { real_target: _, imaginary_target: _ }
             | TerminatorKind::FalseUnwind { real_target: _, unwind: _ } => {

compiler/rustc_borrowck/src/lib.rs

@@ -770,9 +770,9 @@ impl<'cx, 'tcx, R> rustc_mir_dataflow::ResultsVisitor<'cx, 'tcx, R> for MirBorro
             }
 
             TerminatorKind::Goto { target: _ }
-            | TerminatorKind::Terminate
+            | TerminatorKind::UnwindTerminate
             | TerminatorKind::Unreachable
-            | TerminatorKind::Resume
+            | TerminatorKind::UnwindResume
             | TerminatorKind::Return
             | TerminatorKind::GeneratorDrop
             | TerminatorKind::FalseEdge { real_target: _, imaginary_target: _ }
@@ -803,7 +803,9 @@ impl<'cx, 'tcx, R> rustc_mir_dataflow::ResultsVisitor<'cx, 'tcx, R> for MirBorro
                 }
             }
 
-            TerminatorKind::Resume | TerminatorKind::Return | TerminatorKind::GeneratorDrop => {
+            TerminatorKind::UnwindResume
+            | TerminatorKind::Return
+            | TerminatorKind::GeneratorDrop => {
                 // Returning from the function implicitly kills storage for all locals and statics.
                 // Often, the storage will already have been killed by an explicit
                 // StorageDead, but we don't always emit those (notably on unwind paths),
@@ -815,7 +817,7 @@ impl<'cx, 'tcx, R> rustc_mir_dataflow::ResultsVisitor<'cx, 'tcx, R> for MirBorro
                 }
             }
 
-            TerminatorKind::Terminate
+            TerminatorKind::UnwindTerminate
             | TerminatorKind::Assert { .. }
             | TerminatorKind::Call { .. }
             | TerminatorKind::Drop { .. }

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -1333,8 +1333,8 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
         debug!("terminator kind: {:?}", term.kind);
         match &term.kind {
             TerminatorKind::Goto { .. }
-            | TerminatorKind::Resume
-            | TerminatorKind::Terminate
+            | TerminatorKind::UnwindResume
+            | TerminatorKind::UnwindTerminate
             | TerminatorKind::Return
             | TerminatorKind::GeneratorDrop
             | TerminatorKind::Unreachable
@@ -1608,12 +1608,12 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                     self.assert_iscleanup(body, block_data, *target, is_cleanup);
                 }
             }
-            TerminatorKind::Resume => {
+            TerminatorKind::UnwindResume => {
                 if !is_cleanup {
                     span_mirbug!(self, block_data, "resume on non-cleanup block!")
                 }
             }
-            TerminatorKind::Terminate => {
+            TerminatorKind::UnwindTerminate => {
                 if !is_cleanup {
                     span_mirbug!(self, block_data, "abort on non-cleanup block!")
                 }

compiler/rustc_codegen_cranelift/src/base.rs

@@ -474,10 +474,10 @@ fn codegen_fn_body(fx: &mut FunctionCx<'_, '_, '_>, start_block: Block) {
                     *destination,
                 );
             }
-            TerminatorKind::Terminate => {
+            TerminatorKind::UnwindTerminate => {
                 codegen_panic_cannot_unwind(fx, source_info);
             }
-            TerminatorKind::Resume => {
+            TerminatorKind::UnwindResume => {
                 // FIXME implement unwinding
                 fx.bcx.ins().trap(TrapCode::UnreachableCodeReached);
             }

compiler/rustc_codegen_cranelift/src/constant.rs

@@ -550,8 +550,8 @@ pub(crate) fn mir_operand_get_const_val<'tcx>(
                 match &bb_data.terminator().kind {
                     TerminatorKind::Goto { .. }
                     | TerminatorKind::SwitchInt { .. }
-                    | TerminatorKind::Resume
-                    | TerminatorKind::Terminate
+                    | TerminatorKind::UnwindResume
+                    | TerminatorKind::UnwindTerminate
                     | TerminatorKind::Return
                     | TerminatorKind::Unreachable
                     | TerminatorKind::Drop { .. }

compiler/rustc_codegen_ssa/src/mir/analyze.rs

@@ -284,8 +284,8 @@ pub fn cleanup_kinds(mir: &mir::Body<'_>) -> IndexVec<mir::BasicBlock, CleanupKi
         for (bb, data) in mir.basic_blocks.iter_enumerated() {
             match data.terminator().kind {
                 TerminatorKind::Goto { .. }
-                | TerminatorKind::Resume
-                | TerminatorKind::Terminate
+                | TerminatorKind::UnwindResume
+                | TerminatorKind::UnwindTerminate
                 | TerminatorKind::Return
                 | TerminatorKind::GeneratorDrop
                 | TerminatorKind::Unreachable

compiler/rustc_codegen_ssa/src/mir/block.rs

@@ -1224,12 +1224,12 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
 
         self.set_debug_loc(bx, terminator.source_info);
         match terminator.kind {
-            mir::TerminatorKind::Resume => {
+            mir::TerminatorKind::UnwindResume => {
                 self.codegen_resume_terminator(helper, bx);
                 MergingSucc::False
             }
 
-            mir::TerminatorKind::Terminate => {
+            mir::TerminatorKind::UnwindTerminate => {
                 self.codegen_terminate_terminator(helper, bx, terminator);
                 MergingSucc::False
             }

compiler/rustc_const_eval/src/const_eval/error.rs

@@ -18,7 +18,6 @@ pub enum ConstEvalErrKind {
     ModifiedGlobal,
     AssertFailure(AssertKind<ConstInt>),
     Panic { msg: Symbol, line: u32, col: u32, file: Symbol },
-    Abort(String),
 }
 
 impl MachineStopType for ConstEvalErrKind {
@@ -30,7 +29,6 @@ impl MachineStopType for ConstEvalErrKind {
             ModifiedGlobal => const_eval_modified_global,
             Panic { .. } => const_eval_panic,
             AssertFailure(x) => x.diagnostic_message(),
-            Abort(msg) => msg.to_string().into(),
         }
     }
     fn add_args(
@@ -39,7 +37,7 @@ impl MachineStopType for ConstEvalErrKind {
     ) {
         use ConstEvalErrKind::*;
         match *self {
-            ConstAccessesStatic | ModifiedGlobal | Abort(_) => {}
+            ConstAccessesStatic | ModifiedGlobal => {}
             AssertFailure(kind) => kind.add_args(adder),
             Panic { msg, line, col, file } => {
                 adder("msg".into(), msg.into_diagnostic_arg());

compiler/rustc_const_eval/src/const_eval/machine.rs

@@ -464,6 +464,13 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir,
         Ok(Some((ecx.load_mir(instance.def, None)?, orig_instance)))
     }
 
+    fn panic_nounwind(ecx: &mut InterpCx<'mir, 'tcx, Self>, msg: &str) -> InterpResult<'tcx> {
+        let msg = Symbol::intern(msg);
+        let span = ecx.find_closest_untracked_caller_location();
+        let (file, line, col) = ecx.location_triple_for_span(span);
+        Err(ConstEvalErrKind::Panic { msg, file, line, col }.into())
+    }
+
     fn call_intrinsic(
         ecx: &mut InterpCx<'mir, 'tcx, Self>,
         instance: ty::Instance<'tcx>,
@@ -584,10 +591,6 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir,
         Err(ConstEvalErrKind::AssertFailure(err).into())
     }
 
-    fn abort(_ecx: &mut InterpCx<'mir, 'tcx, Self>, msg: String) -> InterpResult<'tcx, !> {
-        Err(ConstEvalErrKind::Abort(msg).into())
-    }
-
     fn binary_ptr_op(
         _ecx: &InterpCx<'mir, 'tcx, Self>,
         _bin_op: mir::BinOp,

compiler/rustc_const_eval/src/interpret/eval_context.rs

@@ -765,7 +765,10 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             }
             mir::UnwindAction::Terminate => {
                 self.frame_mut().loc = Right(self.frame_mut().body.span);
-                M::abort(self, "panic in a function that cannot unwind".to_owned())?;
+                M::unwind_terminate(self)?;
+                // This might have pushed a new stack frame, or it terminated execution.
+                // Either way, `loc` will not be updated.
+                return Ok(());
             }
         };
         Ok(())
@@ -865,6 +868,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                     panic!("encountered StackPopCleanup::Root when unwinding!")
                 }
             };
+            // This must be the very last thing that happens, since it can in fact push a new stack frame.
             self.unwind_to_block(unwind)
         } else {
             // Follow the normal return edge.

compiler/rustc_const_eval/src/interpret/intrinsics.rs

@@ -125,15 +125,9 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
     ) -> InterpResult<'tcx, bool> {
         let instance_args = instance.args;
         let intrinsic_name = self.tcx.item_name(instance.def_id());
-
-        // First handle intrinsics without return place.
-        let ret = match ret {
-            None => match intrinsic_name {
-                sym::abort => M::abort(self, "the program aborted execution".to_owned())?,
-                // Unsupported diverging intrinsic.
-                _ => return Ok(false),
-            },
-            Some(p) => p,
+        let Some(ret) = ret else {
+            // We don't support any intrinsic without return place.
+            return Ok(false);
         };
 
         match intrinsic_name {
@@ -410,7 +404,9 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                         ValidityRequirement::Uninit => bug!("assert_uninit_valid doesn't exist"),
                     };
 
-                    M::abort(self, msg)?;
+                    M::panic_nounwind(self, &msg)?;
+                    // Skip the `go_to_block` at the end.
+                    return Ok(true);
                 }
             }
             sym::simd_insert => {

compiler/rustc_const_eval/src/interpret/machine.rs

@@ -218,10 +218,11 @@ pub trait Machine<'mir, 'tcx: 'mir>: Sized {
         unwind: mir::UnwindAction,
     ) -> InterpResult<'tcx>;
 
-    /// Called to abort evaluation.
-    fn abort(_ecx: &mut InterpCx<'mir, 'tcx, Self>, _msg: String) -> InterpResult<'tcx, !> {
-        throw_unsup_format!("aborting execution is not supported")
-    }
+    /// Called to trigger a non-unwinding panic.
+    fn panic_nounwind(_ecx: &mut InterpCx<'mir, 'tcx, Self>, msg: &str) -> InterpResult<'tcx>;
+
+    /// Called when unwinding reached a state where execution should be terminated.
+    fn unwind_terminate(_ecx: &mut InterpCx<'mir, 'tcx, Self>) -> InterpResult<'tcx>;
 
     /// Called for all binary operations where the LHS has pointer type.
     ///
@@ -499,6 +500,11 @@ pub macro compile_time_machine(<$mir: lifetime, $tcx: lifetime>) {
         false
     }
 
+    #[inline(always)]
+    fn unwind_terminate(_ecx: &mut InterpCx<$mir, $tcx, Self>) -> InterpResult<$tcx> {
+        unreachable!("unwinding cannot happen during compile-time evaluation")
+    }
+
     #[inline(always)]
     fn call_extra_fn(
         _ecx: &mut InterpCx<$mir, $tcx, Self>,

compiler/rustc_const_eval/src/interpret/terminator.rs

@@ -196,15 +196,14 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 }
             }
 
-            Terminate => {
-                // FIXME: maybe should call `panic_no_unwind` lang item instead.
-                M::abort(self, "panic in a function that cannot unwind".to_owned())?;
+            UnwindTerminate => {
+                M::unwind_terminate(self)?;
             }
 
             // When we encounter Resume, we've finished unwinding
             // cleanup for the current stack frame. We pop it in order
             // to continue unwinding the next frame
-            Resume => {
+            UnwindResume => {
                 trace!("unwinding: resuming from cleanup");
                 // By definition, a Resume terminator means
                 // that we're unwinding

compiler/rustc_const_eval/src/transform/check_consts/check.rs

@@ -1037,7 +1037,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
                 self.check_op(ops::Generator(hir::GeneratorKind::Gen))
             }
 
-            TerminatorKind::Terminate => {
+            TerminatorKind::UnwindTerminate => {
                 // Cleanup blocks are skipped for const checking (see `visit_basic_block_data`).
                 span_bug!(self.span, "`Terminate` terminator outside of cleanup block")
             }
@@ -1046,7 +1046,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
             | TerminatorKind::FalseEdge { .. }
             | TerminatorKind::FalseUnwind { .. }
             | TerminatorKind::Goto { .. }
-            | TerminatorKind::Resume
+            | TerminatorKind::UnwindResume
             | TerminatorKind::Return
             | TerminatorKind::SwitchInt { .. }
             | TerminatorKind::Unreachable => {}

compiler/rustc_const_eval/src/transform/check_consts/post_drop_elaboration.rs

@@ -106,15 +106,15 @@ impl<'tcx> Visitor<'tcx> for CheckLiveDrops<'_, 'tcx> {
                 }
             }
 
-            mir::TerminatorKind::Terminate
+            mir::TerminatorKind::UnwindTerminate
             | mir::TerminatorKind::Call { .. }
             | mir::TerminatorKind::Assert { .. }
             | mir::TerminatorKind::FalseEdge { .. }
             | mir::TerminatorKind::FalseUnwind { .. }
             | mir::TerminatorKind::GeneratorDrop
             | mir::TerminatorKind::Goto { .. }
             | mir::TerminatorKind::InlineAsm { .. }
-            | mir::TerminatorKind::Resume
+            | mir::TerminatorKind::UnwindResume
             | mir::TerminatorKind::Return
             | mir::TerminatorKind::SwitchInt { .. }
             | mir::TerminatorKind::Unreachable

compiler/rustc_const_eval/src/transform/validate.rs

@@ -492,19 +492,19 @@ impl<'a, 'tcx> Visitor<'tcx> for CfgChecker<'a, 'tcx> {
                     );
                 }
             }
-            TerminatorKind::Resume => {
+            TerminatorKind::UnwindResume => {
                 let bb = location.block;
                 if !self.body.basic_blocks[bb].is_cleanup {
-                    self.fail(location, "Cannot `Resume` from non-cleanup basic block")
+                    self.fail(location, "Cannot `UnwindResume` from non-cleanup basic block")
                 }
                 if !self.can_unwind {
-                    self.fail(location, "Cannot `Resume` in a function that cannot unwind")
+                    self.fail(location, "Cannot `UnwindResume` in a function that cannot unwind")
                 }
             }
-            TerminatorKind::Terminate => {
+            TerminatorKind::UnwindTerminate => {
                 let bb = location.block;
                 if !self.body.basic_blocks[bb].is_cleanup {
-                    self.fail(location, "Cannot `Terminate` from non-cleanup basic block")
+                    self.fail(location, "Cannot `UnwindTerminate` from non-cleanup basic block")
                 }
             }
             TerminatorKind::Return => {
@@ -1232,8 +1232,8 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
             | TerminatorKind::FalseUnwind { .. }
             | TerminatorKind::InlineAsm { .. }
             | TerminatorKind::GeneratorDrop
-            | TerminatorKind::Resume
-            | TerminatorKind::Terminate
+            | TerminatorKind::UnwindResume
+            | TerminatorKind::UnwindTerminate
             | TerminatorKind::Return
             | TerminatorKind::Unreachable => {}
         }

compiler/rustc_middle/src/mir/patch.rs

@@ -35,7 +35,7 @@ impl<'tcx> MirPatch<'tcx> {
 
         for (bb, block) in body.basic_blocks.iter_enumerated() {
             // Check if we already have a resume block
-            if let TerminatorKind::Resume = block.terminator().kind && block.statements.is_empty() {
+            if let TerminatorKind::UnwindResume = block.terminator().kind && block.statements.is_empty() {
                 result.resume_block = Some(bb);
                 continue;
             }
@@ -50,7 +50,7 @@ impl<'tcx> MirPatch<'tcx> {
             }
 
             // Check if we already have a terminate block
-            if let TerminatorKind::Terminate = block.terminator().kind && block.statements.is_empty() {
+            if let TerminatorKind::UnwindTerminate = block.terminator().kind && block.statements.is_empty() {
                 result.terminate_block = Some(bb);
                 continue;
             }
@@ -68,7 +68,7 @@ impl<'tcx> MirPatch<'tcx> {
             statements: vec![],
             terminator: Some(Terminator {
                 source_info: SourceInfo::outermost(self.body_span),
-                kind: TerminatorKind::Resume,
+                kind: TerminatorKind::UnwindResume,
             }),
             is_cleanup: true,
         });
@@ -102,7 +102,7 @@ impl<'tcx> MirPatch<'tcx> {
             statements: vec![],
             terminator: Some(Terminator {
                 source_info: SourceInfo::outermost(self.body_span),
-                kind: TerminatorKind::Terminate,
+                kind: TerminatorKind::UnwindTerminate,
             }),
             is_cleanup: true,
         });