Partial support for Generator type (model-checking#486)

Partial support for Generator type

compiler/rustc_codegen_llvm/src/gotoc/cbmc/goto_program/expr.rs

@@ -351,7 +351,7 @@ macro_rules! expr {
 impl Expr {
     /// `&self`
     pub fn address_of(self) -> Self {
-        assert!(self.can_take_address_of());
+        assert!(self.can_take_address_of(), "Can't take address of {:?}", self);
         expr!(AddressOf(self), self.typ.clone().to_pointer())
     }
 
@@ -566,9 +566,11 @@ impl Expr {
             self,
             field,
         );
-
-        let typ = symbol_table.lookup_field_type_in_type(self.typ(), field).unwrap().clone();
-        expr!(Member { lhs: self, field: field.to_string() }, typ)
+        if let Some(ty) = symbol_table.lookup_field_type_in_type(self.typ(), field) {
+            expr!(Member { lhs: self, field: field.to_string() }, ty.clone())
+        } else {
+            unreachable!("unable to find field {:?} for type {:?}", field, self.typ())
+        }
     }
 
     /// `__nondet_typ()`
@@ -603,8 +605,9 @@ impl Expr {
         // Check that each formal field has an value
         assert!(
             fields.iter().zip(values.iter()).all(|(f, v)| f.typ() == *v.typ()),
-            "Error in struct_expr; value type does not match field type.\n\t{:?}\n\t{:?}",
+            "Error in struct_expr; value type does not match field type.\n\t{:?}\n\t{:?}\n\t{:?}",
             typ,
+            fields,
             values
         );
         expr!(Struct { values }, typ)
@@ -709,8 +712,9 @@ impl Expr {
                 .iter()
                 .zip(non_padding_values.iter())
                 .all(|(f, v)| f.field_typ().unwrap() == v.typ()),
-            "Error in struct_expr; value type does not match field type.\n\t{:?}\n\t{:?}",
+            "Error in struct_expr; value type does not match field type.\n\t{:?}\n\t{:?}\n\t{:?}",
             typ,
+            non_padding_fields,
             non_padding_values
         );
 
@@ -748,8 +752,9 @@ impl Expr {
         );
         assert!(
             fields.iter().zip(values.iter()).all(|(f, v)| &f.typ() == v.typ()),
-            "Error in struct_expr; value type does not match field type.\n\t{:?}\n\t{:?}",
+            "Error in struct_expr; value type does not match field type.\n\t{:?}\n\t{:?}\n\t{:?}",
             typ,
+            fields,
             values
         );
 

compiler/rustc_codegen_llvm/src/gotoc/cbmc/goto_program/symbol.rs

@@ -209,7 +209,7 @@ impl Symbol {
 /// Setters
 impl Symbol {
     pub fn update_fn_declaration_with_definition(&mut self, body: Stmt) {
-        assert!(self.is_function_declaration());
+        assert!(self.is_function_declaration(), "Expected function declaration, got {:?}", self);
         self.value = SymbolValues::Stmt(body);
     }
 

compiler/rustc_codegen_llvm/src/gotoc/mir_to_goto/codegen/function.rs

@@ -25,6 +25,10 @@ impl<'tcx> GotocCtx<'tcx> {
             name if name.starts_with("bridge::client") => true,
             // https://github.com/model-checking/rmc/issues/282
             "bridge::closure::Closure::<'a, A, R>::call" => true,
+            // Generators
+            name if name.starts_with("<std::future::from_generator::GenFuture<T>") => true,
+            name if name.contains("reusable_box::ReusableBoxFuture") => true,
+            "tokio::sync::Semaphore::acquire_owned::{closure#0}" => true,
             _ => false,
         }
     }
@@ -64,7 +68,6 @@ impl<'tcx> GotocCtx<'tcx> {
         self.set_current_fn(instance);
         let name = self.current_fn().name();
         let old_sym = self.symbol_table.lookup(&name).unwrap();
-        assert!(old_sym.is_function());
         if old_sym.is_function_definition() {
             warn!("Double codegen of {:?}", old_sym);
         } else if self.should_skip_current_fn() {
@@ -79,6 +82,7 @@ impl<'tcx> GotocCtx<'tcx> {
             );
             self.symbol_table.update_fn_declaration_with_definition(&name, body);
         } else {
+            assert!(old_sym.is_function());
             let mir = self.current_fn().mir();
             self.print_instance(instance, mir);
             let labels = self

compiler/rustc_codegen_llvm/src/gotoc/mir_to_goto/codegen/intrinsic.rs

@@ -60,7 +60,9 @@ impl<'tcx> GotocCtx<'tcx> {
                 let dst = fargs.remove(0).cast_to(Type::void_pointer());
                 let count = fargs.remove(0);
                 let sz = {
-                    match self.fn_sig_of_instance(instance).skip_binder().inputs()[0].kind() {
+                    match self.fn_sig_of_instance(instance).unwrap().skip_binder().inputs()[0]
+                        .kind()
+                    {
                         ty::RawPtr(t) => {
                             let layout = self.layout_of(t.ty);
                             Expr::int_constant(layout.size.bytes(), Type::size_t())
@@ -259,17 +261,9 @@ impl<'tcx> GotocCtx<'tcx> {
             "atomic_and_acqrel" => codegen_atomic_binop!(bitand),
             "atomic_and_rel" => codegen_atomic_binop!(bitand),
             "atomic_and_relaxed" => codegen_atomic_binop!(bitand),
-            "atomic_cxchg" => self.codegen_atomic_cxchg(intrinsic, fargs, p, loc),
-            "atomic_cxchg_acq" => self.codegen_atomic_cxchg(intrinsic, fargs, p, loc),
-            "atomic_cxchg_acq_failrelaxed" => self.codegen_atomic_cxchg(intrinsic, fargs, p, loc),
-            "atomic_cxchg_acqrel" => self.codegen_atomic_cxchg(intrinsic, fargs, p, loc),
-            "atomic_cxchg_acqrel_failrelaxed" => {
+            name if name.starts_with("atomic_cxchg") => {
                 self.codegen_atomic_cxchg(intrinsic, fargs, p, loc)
             }
-            "atomic_cxchg_failacq" => self.codegen_atomic_cxchg(intrinsic, fargs, p, loc),
-            "atomic_cxchg_failrelaxed" => self.codegen_atomic_cxchg(intrinsic, fargs, p, loc),
-            "atomic_cxchg_rel" => self.codegen_atomic_cxchg(intrinsic, fargs, p, loc),
-            "atomic_cxchg_relaxed" => self.codegen_atomic_cxchg(intrinsic, fargs, p, loc),
             "atomic_fence" => self.codegen_atomic_noop(intrinsic, loc),
             "atomic_fence_acq" => self.codegen_atomic_noop(intrinsic, loc),
             "atomic_fence_acqrel" => self.codegen_atomic_noop(intrinsic, loc),

compiler/rustc_codegen_llvm/src/gotoc/mir_to_goto/codegen/operand.rs

@@ -573,7 +573,7 @@ impl<'tcx> GotocCtx<'tcx> {
 
     pub fn codegen_func_expr(&mut self, instance: Instance<'tcx>, span: Option<&Span>) -> Expr {
         let func = self.symbol_name(instance);
-        let funct = self.codegen_function_sig(self.fn_sig_of_instance(instance));
+        let funct = self.codegen_function_sig(self.fn_sig_of_instance(instance).unwrap());
         // make sure the functions imported from other modules are in the symbol table
         self.ensure(&func, |ctx, _| {
             Symbol::function(

compiler/rustc_codegen_llvm/src/gotoc/mir_to_goto/codegen/place.rs

@@ -207,6 +207,12 @@ impl<'tcx> GotocCtx<'tcx> {
                         res.member(&field.ident.name.to_string(), &self.symbol_table)
                     }
                     ty::Closure(..) => res.member(&f.index().to_string(), &self.symbol_table),
+                    ty::Generator(..) => self.codegen_unimplemented(
+                        "ty::Generator",
+                        Type::code(vec![], Type::empty()),
+                        res.location().clone(),
+                        "https://github.com/model-checking/rmc/issues/416",
+                    ),
                     _ => unimplemented!(),
                 }
             }
@@ -235,7 +241,9 @@ impl<'tcx> GotocCtx<'tcx> {
             // A local that is itself a FnDef, like Fn::call_once
             ty::FnDef(defid, substs) => Some(self.codegen_fndef(*defid, substs, None)),
             // A local can be pointer to a FnDef, like Fn::call and Fn::call_mut
-            ty::RawPtr(inner) => self.codegen_local_fndef(inner.ty).map(|f| f.address_of()),
+            ty::RawPtr(inner) => self
+                .codegen_local_fndef(inner.ty)
+                .map(|f| if f.can_take_address_of() { f.address_of() } else { f }),
             // A local can be a boxed function pointer
             ty::Adt(def, _) if def.is_box() => {
                 let boxed_ty = self.codegen_ty(ty);

compiler/rustc_codegen_llvm/src/gotoc/mir_to_goto/codegen/statement.rs

@@ -42,7 +42,7 @@ impl<'tcx> GotocCtx<'tcx> {
             TerminatorKind::Resume => Stmt::assert_false("resume instruction", loc),
             TerminatorKind::Abort => Stmt::assert_false("abort instruction", loc),
             TerminatorKind::Return => {
-                let rty = self.current_fn().sig().skip_binder().output();
+                let rty = self.current_fn().sig().unwrap().skip_binder().output();
                 if rty.is_unit() {
                     self.codegen_ret_unit()
                 } else {
@@ -358,8 +358,12 @@ impl<'tcx> GotocCtx<'tcx> {
                         // should be a fat pointer for the trait
                         let trait_fat_ptr = fargs[0].to_owned();
 
-                        // Check the Gotoc-level fat pointer type
-                        assert!(trait_fat_ptr.typ().is_rust_trait_fat_ptr(&self.symbol_table));
+                        //Check the Gotoc-level fat pointer type
+                        assert!(
+                            trait_fat_ptr.typ().is_rust_trait_fat_ptr(&self.symbol_table),
+                            "Expected fat pointer, got:\n{:?}",
+                            trait_fat_ptr,
+                        );
 
                         self.codegen_virtual_funcall(
                             trait_fat_ptr,
@@ -537,6 +541,16 @@ impl<'tcx> GotocCtx<'tcx> {
                 let pt = self.place_ty(place);
                 let (def, _) = match pt.kind() {
                     ty::Adt(def, substs) => (def, substs),
+                    ty::Generator(..) => {
+                        return self
+                            .codegen_unimplemented(
+                                "ty::Generator",
+                                Type::code(vec![], Type::empty()),
+                                Location::none(),
+                                "https://github.com/model-checking/rmc/issues/416",
+                            )
+                            .as_stmt(Location::none());
+                    }
                     _ => unreachable!(),
                 };
                 let layout = self.layout_of(pt);

compiler/rustc_codegen_llvm/src/gotoc/mir_to_goto/codegen/typ.rs

@@ -148,20 +148,21 @@ impl<'tcx> GotocCtx<'tcx> {
         self.sig_with_closure_untupled(sig)
     }
 
-    pub fn fn_sig_of_instance(&self, instance: Instance<'tcx>) -> ty::PolyFnSig<'tcx> {
+    pub fn fn_sig_of_instance(&self, instance: Instance<'tcx>) -> Option<ty::PolyFnSig<'tcx>> {
         let fntyp = instance.ty(self.tcx, ty::ParamEnv::reveal_all());
         self.monomorphize(match fntyp.kind() {
-            ty::Closure(def_id, subst) => self.closure_sig(*def_id, subst),
+            ty::Closure(def_id, subst) => Some(self.closure_sig(*def_id, subst)),
             ty::FnPtr(..) | ty::FnDef(..) => {
                 let sig = fntyp.fn_sig(self.tcx);
                 // Some virtual calls through a vtable may actually be closures
                 // or shims that also need the arguments untupled, even though
                 // the kind of the trait type is not a ty::Closure.
                 if self.ty_needs_closure_untupled(fntyp) {
-                    return self.sig_with_closure_untupled(sig);
+                    return Some(self.sig_with_closure_untupled(sig));
                 }
-                sig
+                Some(sig)
             }
+            ty::Generator(_def_id, _substs, _movability) => None,
             _ => unreachable!("Can't get function signature of type: {:?}", fntyp),
         })
     }
@@ -243,7 +244,7 @@ impl<'tcx> GotocCtx<'tcx> {
         idx: usize,
     ) -> DatatypeComponent {
         // Gives a binder with function signature
-        let sig = self.fn_sig_of_instance(instance);
+        let sig = self.fn_sig_of_instance(instance).unwrap();
 
         // Gives an Irep Pointer object for the signature
         let fn_ty = self.codegen_dynamic_function_sig(sig);
@@ -367,14 +368,6 @@ impl<'tcx> GotocCtx<'tcx> {
         //   StructTag("tag-std::boxed::Box<dyn std::error::Error + std::marker::Send + std::marker::Sync>") }
         let t = self.monomorphize(t);
         with_no_trimmed_paths(|| printer.print_type(t).unwrap());
-        // TODO: The following line is a temporary measure to remove the static lifetime
-        // appearing as \'static in mangled type names.  This should be done using regular
-        // expressions to handle more or less whitespace around the lifetime, but this
-        // requires adding the regex module to the dependencies in Cargo.toml.  This should
-        // probably be done modifying the rustc pretty printer, but that is deep in the rustc
-        // code.  See the implementation of pretty_print_region on line 1720 in
-        // compiler/rustc_middle/src/ty/print/pretty.rs.
-        let name = name.replace(" + \'static", "").replace("\'static ", "");
 
         // Crate resolution: mangled names need to be distinct across different versions
         // of the same crate that could be pulled in by dependencies. However, RMC's
@@ -493,7 +486,7 @@ impl<'tcx> GotocCtx<'tcx> {
             }
             ty::FnPtr(sig) => self.codegen_function_sig(*sig).to_pointer(),
             ty::Closure(_, subst) => self.codegen_ty_closure(ty, subst),
-            ty::Generator(_, _, _) => unimplemented!(),
+            ty::Generator(_, subst, _) => self.codegen_ty_generator(subst),
             ty::Never =>
             // unfortunately, there is no bottom in C. We must pick a type
             {
@@ -681,6 +674,15 @@ impl<'tcx> GotocCtx<'tcx> {
         })
     }
 
+    /// Preliminary support for the Generator type kind. The core functionality remains
+    /// unimplemented, but this way we fail at verification time only if paths that
+    /// rely on Generator types are used.
+    fn codegen_ty_generator(&mut self, substs: ty::subst::SubstsRef<'tcx>) -> Type {
+        let tys = substs.as_generator().upvar_tys().map(|t| self.codegen_ty(t)).collect();
+        let output = self.codegen_ty(substs.as_generator().return_ty());
+        Type::code_with_unnamed_parameters(tys, output)
+    }
+
     pub fn codegen_fat_ptr(&mut self, mir_type: Ty<'tcx>) -> Type {
         assert!(
             !self.use_thin_pointer(mir_type),
@@ -1125,7 +1127,8 @@ impl<'tcx> GotocCtx<'tcx> {
     /// the function type of the current instance
     pub fn fn_typ(&mut self) -> Type {
         let sig = self.current_fn().sig();
-        let sig = self.tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), sig);
+        let sig =
+            self.tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), sig.unwrap());
         // we don't call [codegen_function_sig] because we want to get a bit more metainformation.
         let mut params: Vec<Parameter> = sig
             .inputs()

compiler/rustc_codegen_llvm/src/gotoc/mir_to_goto/context/current_fn.rs

@@ -25,7 +25,7 @@ pub struct CurrentFnCtx<'tcx> {
     /// A human readable pretty name for the current function
     readable_name: String,
     /// The signature of the current function
-    sig: PolyFnSig<'tcx>,
+    sig: Option<PolyFnSig<'tcx>>,
     /// A counter to enable creating temporary variables
     temp_var_counter: u64,
 }
@@ -111,7 +111,7 @@ impl CurrentFnCtx<'tcx> {
     }
 
     /// The signature of the function we are currently compiling
-    pub fn sig(&self) -> PolyFnSig<'tcx> {
+    pub fn sig(&self) -> Option<PolyFnSig<'tcx>> {
         self.sig
     }
 }

compiler/rustc_codegen_llvm/src/gotoc/mir_to_goto/overrides/hooks.rs

@@ -10,15 +10,13 @@
 
 use super::stubs::{HashMapStub, VecStub};
 use crate::gotoc::cbmc::goto_program::{BuiltinFn, Expr, Location, Stmt, Symbol, Type};
-use crate::gotoc::mir_to_goto::utils::{
-    instance_name_is, instance_name_starts_with, sig_of_instance,
-};
+use crate::gotoc::mir_to_goto::utils::{instance_name_is, instance_name_starts_with};
 use crate::gotoc::mir_to_goto::GotocCtx;
 use rustc_hir::definitions::DefPathDataName;
 use rustc_middle::mir::{BasicBlock, Place};
 use rustc_middle::ty::layout::LayoutOf;
 use rustc_middle::ty::print::with_no_trimmed_paths;
-use rustc_middle::ty::{Instance, InstanceDef, Ty, TyCtxt};
+use rustc_middle::ty::{self, Instance, InstanceDef, Ty, TyCtxt};
 use rustc_span::Span;
 use std::rc::Rc;
 
@@ -42,6 +40,31 @@ pub trait GotocHook<'tcx> {
     ) -> Stmt;
 }
 
+fn output_of_instance_is_never<'tcx>(tcx: TyCtxt<'tcx>, instance: Instance<'tcx>) -> bool {
+    let ty = instance.ty(tcx, ty::ParamEnv::reveal_all());
+    match ty.kind() {
+        ty::Closure(_, substs) => tcx
+            .normalize_erasing_late_bound_regions(
+                ty::ParamEnv::reveal_all(),
+                substs.as_closure().sig(),
+            )
+            .output()
+            .is_never(),
+        ty::FnDef(..) | ty::FnPtr(..) => tcx
+            .normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), ty.fn_sig(tcx))
+            .output()
+            .is_never(),
+        ty::Generator(_, substs, _) => substs.as_generator().return_ty().is_never(),
+        _ => {
+            unreachable!(
+                "Can't take get ouput type of instance:\n{:?}\nType kind:\n{:?}",
+                ty,
+                ty.kind()
+            )
+        }
+    }
+}
+
 struct ExpectFail;
 impl<'tcx> GotocHook<'tcx> for ExpectFail {
     fn hook_applies(&self, tcx: TyCtxt<'tcx>, instance: Instance<'tcx>) -> bool {
@@ -166,7 +189,7 @@ struct Panic;
 
 impl<'tcx> GotocHook<'tcx> for Panic {
     fn hook_applies(&self, tcx: TyCtxt<'tcx>, instance: Instance<'tcx>) -> bool {
-        sig_of_instance(tcx, instance).output().is_never()
+        output_of_instance_is_never(tcx, instance)
             && (instance_name_is(tcx, instance, "begin_panic")
                 || instance_name_is(tcx, instance, "panic"))
     }
@@ -188,8 +211,7 @@ struct Nevers;
 
 impl<'tcx> GotocHook<'tcx> for Nevers {
     fn hook_applies(&self, tcx: TyCtxt<'tcx>, instance: Instance<'tcx>) -> bool {
-        let sig = sig_of_instance(tcx, instance);
-        sig.output().is_never()
+        output_of_instance_is_never(tcx, instance)
     }
 
     fn handle(

compiler/rustc_codegen_llvm/src/gotoc/mir_to_goto/utils/names.rs

@@ -10,7 +10,7 @@ use rustc_hir::definitions::DefPathDataName;
 use rustc_middle::mir::mono::CodegenUnitNameBuilder;
 use rustc_middle::mir::Local;
 use rustc_middle::ty::print::with_no_trimmed_paths;
-use rustc_middle::ty::{self, Instance, TyCtxt};
+use rustc_middle::ty::{Instance, TyCtxt};
 use tracing::debug;
 
 impl<'tcx> GotocCtx<'tcx> {
@@ -126,14 +126,6 @@ pub fn full_crate_name(tcx: TyCtxt<'tcx>) -> String {
 }
 
 //TODO: These were moved from hooks.rs, where they didn't have a goto context. Normalize them.
-pub fn sig_of_instance<'tcx>(tcx: TyCtxt<'tcx>, instance: Instance<'tcx>) -> ty::FnSig<'tcx> {
-    let ty = instance.ty(tcx, ty::ParamEnv::reveal_all());
-    let sig = match ty.kind() {
-        ty::Closure(_, substs) => substs.as_closure().sig(),
-        _ => ty.fn_sig(tcx),
-    };
-    tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), sig)
-}
 
 /// Helper function to determine if the function name starts with `expected`
 // TODO: rationalize how we match the hooks https://github.com/model-checking/rmc/issues/130