Merge pull request #1247 from bjorn3/melt_some_ice

Melt some ICE

example/mini_core_hello_world.rs

@@ -330,6 +330,17 @@ struct ExternTypeWrapper {
     static REF1: &u8 = &42;
     static REF2: &u8 = REF1;
     assert_eq!(*REF1, *REF2);
+
+    extern "C" {
+        type A;
+    }
+
+    fn main() {
+        let x: &A = unsafe { &*(1usize as *const A) };
+
+        assert_eq!(unsafe { intrinsics::size_of_val(x) }, 0);
+        assert_eq!(unsafe { intrinsics::min_align_of_val(x) }, 1);
+}
 }
 
 #[cfg(all(not(jit), target_arch = "x86_64", target_os = "linux"))]

example/std_example.rs

@@ -128,6 +128,25 @@ enum Nums {
         0 => loop {},
         v => panic(v),
     };
+
+    if black_box(false) {
+        // Based on https://github.com/rust-lang/rust/blob/2f320a224e827b400be25966755a621779f797cc/src/test/ui/debuginfo/debuginfo_with_uninhabitable_field_and_unsized.rs
+        let _ = Foo::<dyn Send>::new();
+
+        #[allow(dead_code)]
+        struct Foo<T: ?Sized> {
+            base: Never,
+            value: T,
+        }
+
+        impl<T: ?Sized> Foo<T> {
+            pub fn new() -> Box<Foo<T>> {
+                todo!()
+            }
+        }
+
+        enum Never {}
+    }
 }
 
 fn panic(_: u128) {

scripts/test_rustc_tests.sh

@@ -99,9 +99,6 @@ rm -r src/test/run-make/remap-path-prefix-dwarf # requires llvm-dwarfdump
 # ============
 rm src/test/ui/allocator/no_std-alloc-error-handler-default.rs # missing rust_oom definition
 
-rm -r src/test/ui/polymorphization/ # polymorphization not yet supported
-rm src/test/codegen-units/polymorphization/unused_type_parameters.rs # same
-
 rm src/test/incremental/spike-neg1.rs # errors out for some reason
 rm src/test/incremental/spike-neg2.rs # same
 rm src/test/ui/issues/issue-74564-if-expr-stack-overflow.rs # gives a stackoverflow before the backend runs

src/abi/mod.rs

@@ -4,6 +4,7 @@
 mod pass_mode;
 mod returning;
 
+use cranelift_module::ModuleError;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc_middle::ty::layout::FnAbiOf;
 use rustc_target::abi::call::{Conv, FnAbi};
@@ -69,7 +70,17 @@ pub(crate) fn import_function<'tcx>(
 ) -> FuncId {
     let name = tcx.symbol_name(inst).name;
     let sig = get_function_sig(tcx, module.isa().triple(), inst);
-    module.declare_function(name, Linkage::Import, &sig).unwrap()
+    match module.declare_function(name, Linkage::Import, &sig) {
+        Ok(func_id) => func_id,
+        Err(ModuleError::IncompatibleDeclaration(_)) => tcx.sess.fatal(&format!(
+            "attempt to declare `{name}` as function, but it was already declared as static"
+        )),
+        Err(ModuleError::IncompatibleSignature(_, prev_sig, new_sig)) => tcx.sess.fatal(&format!(
+            "attempt to declare `{name}` with signature {new_sig:?}, \
+             but it was already declared with signature {prev_sig:?}"
+        )),
+        Err(err) => Err::<_, _>(err).unwrap(),
+    }
 }
 
 impl<'tcx> FunctionCx<'_, '_, 'tcx> {
@@ -182,6 +193,15 @@ enum ArgKind<'tcx> {
     }
 
     let fn_abi = fx.fn_abi.take().unwrap();
+
+    // FIXME implement variadics in cranelift
+    if fn_abi.c_variadic {
+        fx.tcx.sess.span_fatal(
+            fx.mir.span,
+            "Defining variadic functions is not yet supported by Cranelift",
+        );
+    }
+
     let mut arg_abis_iter = fn_abi.args.iter();
 
     let func_params = fx

src/abi/pass_mode.rs

@@ -216,7 +216,7 @@ pub(super) fn adjust_arg_for_abi<'tcx>(
     arg_abi: &ArgAbi<'tcx, Ty<'tcx>>,
     is_owned: bool,
 ) -> SmallVec<[Value; 2]> {
-    assert_assignable(fx, arg.layout().ty, arg_abi.layout.ty);
+    assert_assignable(fx, arg.layout().ty, arg_abi.layout.ty, 16);
     match arg_abi.mode {
         PassMode::Ignore => smallvec![],
         PassMode::Direct(_) => smallvec![arg.load_scalar(fx)],

src/constant.rs

@@ -316,14 +316,18 @@ fn data_id_for_static(
 
     let attrs = tcx.codegen_fn_attrs(def_id);
 
-    let data_id = module
+    let data_id = match module.declare_data(
-        .declare_data(
         &*symbol_name,
         linkage,
         is_mutable,
         attrs.flags.contains(CodegenFnAttrFlags::THREAD_LOCAL),
-        )
+    ) {
-        .unwrap();
+        Ok(data_id) => data_id,
+        Err(ModuleError::IncompatibleDeclaration(_)) => tcx.sess.fatal(&format!(
+            "attempt to declare `{symbol_name}` as static, but it was already declared as function"
+        )),
+        Err(err) => Err::<_, _>(err).unwrap(),
+    };
 
     if rlinkage.is_some() {
         // Comment copied from https://github.com/rust-lang/rust/blob/45060c2a66dfd667f88bd8b94261b28a58d85bd5/src/librustc_codegen_llvm/consts.rs#L141
@@ -428,7 +432,8 @@ fn define_all_allocs(tcx: TyCtxt<'_>, module: &mut dyn Module, cx: &mut Constant
             let data_id = match reloc_target_alloc {
                 GlobalAlloc::Function(instance) => {
                     assert_eq!(addend, 0);
-                    let func_id = crate::abi::import_function(tcx, module, instance);
+                    let func_id =
+                        crate::abi::import_function(tcx, module, instance.polymorphize(tcx));
                     let local_func_id = module.declare_func_in_data(func_id, &mut data_ctx);
                     data_ctx.write_function_addr(offset.bytes() as u32, local_func_id);
                     continue;

src/inline_asm.rs

@@ -18,6 +18,7 @@ pub(crate) fn codegen_inline_asm<'tcx>(
 ) {
     // FIXME add .eh_frame unwind info directives
 
+    if !template.is_empty() {
         if template[0] == InlineAsmTemplatePiece::String("int $$0x29".to_string()) {
             let true_ = fx.bcx.ins().iconst(types::I32, 1);
             fx.bcx.ins().trapnz(true_, TrapCode::User(1));
@@ -25,7 +26,11 @@ pub(crate) fn codegen_inline_asm<'tcx>(
         } else if template[0] == InlineAsmTemplatePiece::String("movq %rbx, ".to_string())
             && matches!(
                 template[1],
-            InlineAsmTemplatePiece::Placeholder { operand_idx: 0, modifier: Some('r'), span: _ }
+                InlineAsmTemplatePiece::Placeholder {
+                    operand_idx: 0,
+                    modifier: Some('r'),
+                    span: _
+                }
             )
             && template[2] == InlineAsmTemplatePiece::String("\n".to_string())
             && template[3] == InlineAsmTemplatePiece::String("cpuid".to_string())
@@ -33,7 +38,11 @@ pub(crate) fn codegen_inline_asm<'tcx>(
             && template[5] == InlineAsmTemplatePiece::String("xchgq %rbx, ".to_string())
             && matches!(
                 template[6],
-            InlineAsmTemplatePiece::Placeholder { operand_idx: 0, modifier: Some('r'), span: _ }
+                InlineAsmTemplatePiece::Placeholder {
+                    operand_idx: 0,
+                    modifier: Some('r'),
+                    span: _
+                }
             )
         {
             assert_eq!(operands.len(), 4);
@@ -99,6 +108,7 @@ pub(crate) fn codegen_inline_asm<'tcx>(
         } else if fx.tcx.symbol_name(fx.instance).name == "__alloca" {
             crate::trap::trap_unimplemented(fx, "Alloca is not supported");
         }
+    }
 
     let mut inputs = Vec::new();
     let mut outputs = Vec::new();

src/intrinsics/mod.rs

@@ -404,7 +404,9 @@ fn codegen_regular_intrinsic_call<'tcx>(
         };
         size_of_val, (c ptr) {
             let layout = fx.layout_of(substs.type_at(0));
-            let size = if layout.is_unsized() {
+            // Note: Can't use is_unsized here as truly unsized types need to take the fixed size
+            // branch
+            let size = if let Abi::ScalarPair(_, _) = ptr.layout().abi {
                 let (_ptr, info) = ptr.load_scalar_pair(fx);
                 let (size, _align) = crate::unsize::size_and_align_of_dst(fx, layout, info);
                 size
@@ -418,7 +420,9 @@ fn codegen_regular_intrinsic_call<'tcx>(
         };
         min_align_of_val, (c ptr) {
             let layout = fx.layout_of(substs.type_at(0));
-            let align = if layout.is_unsized() {
+            // Note: Can't use is_unsized here as truly unsized types need to take the fixed size
+            // branch
+            let align = if let Abi::ScalarPair(_, _) = ptr.layout().abi {
                 let (_ptr, info) = ptr.load_scalar_pair(fx);
                 let (_size, align) = crate::unsize::size_and_align_of_dst(fx, layout, info);
                 align
@@ -1135,6 +1139,20 @@ fn swap(bcx: &mut FunctionBuilder<'_>, v: Value) -> Value {
             // FIXME implement black_box semantics
             ret.write_cvalue(fx, a);
         };
+
+        // FIXME implement variadics in cranelift
+        va_copy, (o _dest, o _src) {
+            fx.tcx.sess.span_fatal(
+                source_info.span,
+                "Defining variadic functions is not yet supported by Cranelift",
+            );
+        };
+        va_arg | va_end, (o _valist) {
+            fx.tcx.sess.span_fatal(
+                source_info.span,
+                "Defining variadic functions is not yet supported by Cranelift",
+            );
+        };
     }
 
     let ret_block = fx.get_block(destination.unwrap());

src/main_shim.rs

@@ -109,7 +109,8 @@ fn create_entry_fn(
                     tcx.mk_substs([GenericArg::from(main_ret_ty)].iter()),
                 )
                 .unwrap()
-                .unwrap();
+                .unwrap()
+                .polymorphize(tcx);
 
                 let report_name = tcx.symbol_name(report).name;
                 let report_sig = get_function_sig(tcx, m.isa().triple(), report);

src/unsize.rs

@@ -153,11 +153,7 @@ pub(crate) fn size_and_align_of_dst<'tcx>(
     layout: TyAndLayout<'tcx>,
     info: Value,
 ) -> (Value, Value) {
-    if !layout.is_unsized() {
+    assert!(layout.is_unsized() || layout.abi == Abi::Uninhabited);
-        let size = fx.bcx.ins().iconst(fx.pointer_type, layout.size.bytes() as i64);
-        let align = fx.bcx.ins().iconst(fx.pointer_type, layout.align.abi.bytes() as i64);
-        return (size, align);
-    }
     match layout.ty.kind() {
         ty::Dynamic(..) => {
             // load size/align from vtable

src/value_and_place.rs

@@ -324,6 +324,12 @@ pub(crate) fn new_stack_slot(
             };
         }
 
+        if layout.size.bytes() >= u64::from(u32::MAX - 16) {
+            fx.tcx
+                .sess
+                .fatal(&format!("values of type {} are too big to store on the stack", layout.ty));
+        }
+
         let stack_slot = fx.bcx.create_stack_slot(StackSlotData {
             kind: StackSlotKind::ExplicitSlot,
             // FIXME Don't force the size to a multiple of 16 bytes once Cranelift gets a way to
@@ -420,7 +426,7 @@ pub(crate) fn to_ptr_maybe_unsized(self) -> (Pointer, Option<Value>) {
     }
 
     pub(crate) fn write_cvalue(self, fx: &mut FunctionCx<'_, '_, 'tcx>, from: CValue<'tcx>) {
-        assert_assignable(fx, from.layout().ty, self.layout().ty);
+        assert_assignable(fx, from.layout().ty, self.layout().ty, 16);
 
         self.write_cvalue_maybe_transmute(fx, from, "write_cvalue");
     }
@@ -782,18 +788,25 @@ pub(crate) fn assert_assignable<'tcx>(
     fx: &FunctionCx<'_, '_, 'tcx>,
     from_ty: Ty<'tcx>,
     to_ty: Ty<'tcx>,
+    limit: usize,
 ) {
+    if limit == 0 {
+        // assert_assignable exists solely to catch bugs in cg_clif. it isn't necessary for
+        // soundness. don't attempt to check deep types to avoid exponential behavior in certain
+        // cases.
+        return;
+    }
     match (from_ty.kind(), to_ty.kind()) {
         (ty::Ref(_, a, _), ty::Ref(_, b, _))
         | (
             ty::RawPtr(TypeAndMut { ty: a, mutbl: _ }),
             ty::RawPtr(TypeAndMut { ty: b, mutbl: _ }),
         ) => {
-            assert_assignable(fx, *a, *b);
+            assert_assignable(fx, *a, *b, limit - 1);
         }
         (ty::Ref(_, a, _), ty::RawPtr(TypeAndMut { ty: b, mutbl: _ }))
         | (ty::RawPtr(TypeAndMut { ty: a, mutbl: _ }), ty::Ref(_, b, _)) => {
-            assert_assignable(fx, *a, *b);
+            assert_assignable(fx, *a, *b, limit - 1);
         }
         (ty::FnPtr(_), ty::FnPtr(_)) => {
             let from_sig = fx.tcx.normalize_erasing_late_bound_regions(
@@ -823,6 +836,17 @@ pub(crate) fn assert_assignable<'tcx>(
             }
             // dyn for<'r> Trait<'r> -> dyn Trait<'_> is allowed
         }
+        (&ty::Tuple(types_a), &ty::Tuple(types_b)) => {
+            let mut types_a = types_a.iter();
+            let mut types_b = types_b.iter();
+            loop {
+                match (types_a.next(), types_b.next()) {
+                    (Some(a), Some(b)) => assert_assignable(fx, a, b, limit - 1),
+                    (None, None) => return,
+                    (Some(_), None) | (None, Some(_)) => panic!("{:#?}/{:#?}", from_ty, to_ty),
+                }
+            }
+        }
         (&ty::Adt(adt_def_a, substs_a), &ty::Adt(adt_def_b, substs_b))
             if adt_def_a.did() == adt_def_b.did() =>
         {
@@ -830,18 +854,37 @@ pub(crate) fn assert_assignable<'tcx>(
             let mut types_b = substs_b.types();
             loop {
                 match (types_a.next(), types_b.next()) {
-                    (Some(a), Some(b)) => assert_assignable(fx, a, b),
+                    (Some(a), Some(b)) => assert_assignable(fx, a, b, limit - 1),
                     (None, None) => return,
                     (Some(_), None) | (None, Some(_)) => panic!("{:#?}/{:#?}", from_ty, to_ty),
                 }
             }
         }
-        (ty::Array(a, _), ty::Array(b, _)) => assert_assignable(fx, *a, *b),
+        (ty::Array(a, _), ty::Array(b, _)) => assert_assignable(fx, *a, *b, limit - 1),
+        (&ty::Closure(def_id_a, substs_a), &ty::Closure(def_id_b, substs_b))
+            if def_id_a == def_id_b =>
+        {
+            let mut types_a = substs_a.types();
+            let mut types_b = substs_b.types();
+            loop {
+                match (types_a.next(), types_b.next()) {
+                    (Some(a), Some(b)) => assert_assignable(fx, a, b, limit - 1),
+                    (None, None) => return,
+                    (Some(_), None) | (None, Some(_)) => panic!("{:#?}/{:#?}", from_ty, to_ty),
+                }
+            }
+        }
+        (ty::Param(_), _) | (_, ty::Param(_)) if fx.tcx.sess.opts.unstable_opts.polymorphize => {
+            // No way to check if it is correct or not with polymorphization enabled
+        }
         _ => {
             assert_eq!(
-                from_ty, to_ty,
+                from_ty,
+                to_ty,
                 "Can't write value with incompatible type {:?} to place with type {:?}\n\n{:#?}",
-                from_ty, to_ty, fx,
+                from_ty.kind(),
+                to_ty.kind(),
+                fx,
             );
         }
     }