Migrate foreign function, compiler-interface and kani-middle modules to use StableMIR (#2959)

We still need internal APIs to handle things like:

- **FnAbi:** Support is pending this PR to be merged:
rust-lang/rust#119094
- **Filter non-function items:** Also pending a fix on the rust side:
rust-lang/rust#119135
- **Checking for reachable functions:** This is not needed in theory,
but std lib build fails since it unncovers an existing issue in Kani
with a function that was not previously included. I'll create an issue
for that. It's unrelated to this change though.
- **Function attribute handling**
- **Span error**

Co-authored-by: Adrian Palacios <[email protected]>

Author: celinval

kani-compiler/src/codegen_cprover_gotoc/codegen/foreign_function.rs

@@ -15,10 +15,10 @@ use crate::kani_middle;
 use cbmc::goto_program::{Expr, Location, Stmt, Symbol, Type};
 use cbmc::{InternString, InternedString};
 use lazy_static::lazy_static;
-use rustc_middle::ty::Instance;
 use rustc_smir::rustc_internal;
 use rustc_target::abi::call::Conv;
-use stable_mir::mir::mono::Instance as InstanceStable;
+use stable_mir::mir::mono::Instance;
+use stable_mir::CrateDef;
 use tracing::{debug, trace};
 
 lazy_static! {
@@ -46,15 +46,16 @@ impl<'tcx> GotocCtx<'tcx> {
     ///
     /// For other foreign items, we declare a shim and add to the list of foreign shims to be
     /// handled later.
-    pub fn codegen_foreign_fn(&mut self, instance: InstanceStable) -> &Symbol {
+    pub fn codegen_foreign_fn(&mut self, instance: Instance) -> &Symbol {
         debug!(?instance, "codegen_foreign_function");
-        let instance = rustc_internal::internal(instance);
-        let fn_name = self.symbol_name(instance).intern();
+        let instance_internal = rustc_internal::internal(instance);
+        let fn_name = self.symbol_name_stable(instance).intern();
         if self.symbol_table.contains(fn_name) {
             // Symbol has been added (either a built-in CBMC function or a Rust allocation function).
             self.symbol_table.lookup(fn_name).unwrap()
         } else if RUST_ALLOC_FNS.contains(&fn_name)
-            || (self.is_cffi_enabled() && kani_middle::fn_abi(self.tcx, instance).conv == Conv::C)
+            || (self.is_cffi_enabled()
+                && kani_middle::fn_abi(self.tcx, instance_internal).conv == Conv::C)
         {
             // Add a Rust alloc lib function as is declared by core.
             // When C-FFI feature is enabled, we just trust the rust declaration.
@@ -63,14 +64,8 @@ impl<'tcx> GotocCtx<'tcx> {
             // https://github.com/model-checking/kani/issues/2426
             self.ensure(fn_name, |gcx, _| {
                 let typ = gcx.codegen_ffi_type(instance);
-                Symbol::function(
-                    fn_name,
-                    typ,
-                    None,
-                    gcx.readable_instance_name(instance),
-                    Location::none(),
-                )
-                .with_is_extern(true)
+                Symbol::function(fn_name, typ, None, instance.name(), Location::none())
+                    .with_is_extern(true)
             })
         } else {
             let shim_name = format!("{fn_name}_ffi_shim");
@@ -82,7 +77,7 @@ impl<'tcx> GotocCtx<'tcx> {
                     &shim_name,
                     typ,
                     Some(gcx.codegen_ffi_shim(shim_name.as_str().into(), instance)),
-                    gcx.readable_instance_name(instance),
+                    instance.name(),
                     Location::none(),
                 )
             })
@@ -96,19 +91,19 @@ impl<'tcx> GotocCtx<'tcx> {
     }
 
     /// Generate code for a foreign function shim.
-    fn codegen_ffi_shim(&mut self, shim_name: InternedString, instance: Instance<'tcx>) -> Stmt {
+    fn codegen_ffi_shim(&mut self, shim_name: InternedString, instance: Instance) -> Stmt {
         debug!(?shim_name, ?instance, sym=?self.symbol_table.lookup(shim_name), "generate_foreign_shim");
 
-        let loc = self.codegen_span(&self.tcx.def_span(instance.def_id()));
+        let loc = self.codegen_span_stable(instance.def.span());
         let unsupported_check = self.codegen_ffi_unsupported(instance, loc);
         Stmt::block(vec![unsupported_check], loc)
     }
 
     /// Generate type for the given foreign instance.
-    fn codegen_ffi_type(&mut self, instance: Instance<'tcx>) -> Type {
-        let fn_name = self.symbol_name(instance);
-        let fn_abi = kani_middle::fn_abi(self.tcx, instance);
-        let loc = self.codegen_span(&self.tcx.def_span(instance.def_id()));
+    fn codegen_ffi_type(&mut self, instance: Instance) -> Type {
+        let fn_name = self.symbol_name_stable(instance);
+        let fn_abi = kani_middle::fn_abi(self.tcx, rustc_internal::internal(instance));
+        let loc = self.codegen_span_stable(instance.def.span());
         let params = fn_abi
             .args
             .iter()
@@ -137,15 +132,15 @@ impl<'tcx> GotocCtx<'tcx> {
     ///
     /// This will behave like `codegen_unimplemented_stmt` but print a message that includes
     /// the name of the function not supported and the calling convention.
-    fn codegen_ffi_unsupported(&mut self, instance: Instance<'tcx>, loc: Location) -> Stmt {
-        let fn_name = &self.symbol_name(instance);
+    fn codegen_ffi_unsupported(&mut self, instance: Instance, loc: Location) -> Stmt {
+        let fn_name = &self.symbol_name_stable(instance);
         debug!(?fn_name, ?loc, "codegen_ffi_unsupported");
 
         // Save this occurrence so we can emit a warning in the compilation report.
         let entry = self.unsupported_constructs.entry("foreign function".into()).or_default();
         entry.push(loc);
 
-        let call_conv = kani_middle::fn_abi(self.tcx, instance).conv;
+        let call_conv = kani_middle::fn_abi(self.tcx, rustc_internal::internal(instance)).conv;
         let msg = format!("call to foreign \"{call_conv:?}\" function `{fn_name}`");
         let url = if call_conv == Conv::C {
             "https://github.com/model-checking/kani/issues/2423"

kani-compiler/src/codegen_cprover_gotoc/codegen/intrinsic.rs

@@ -1331,7 +1331,7 @@ impl<'tcx> GotocCtx<'tcx> {
             TyKind::RigidTy(RigidTy::Slice(_)) | TyKind::RigidTy(RigidTy::Str) => {
                 let unit_t = match ty.kind() {
                     TyKind::RigidTy(RigidTy::Slice(et)) => et,
-                    TyKind::RigidTy(RigidTy::Str) => rustc_internal::stable(self.tcx.types.u8),
+                    TyKind::RigidTy(RigidTy::Str) => Ty::unsigned_ty(UintTy::U8),
                     _ => unreachable!(),
                 };
                 let unit = self.layout_of_stable(unit_t);

kani-compiler/src/codegen_cprover_gotoc/compiler_interface.rs

@@ -16,7 +16,7 @@ use crate::kani_middle::{check_reachable_items, dump_mir_items};
 use crate::kani_queries::QueryDb;
 use cbmc::goto_program::Location;
 use cbmc::irep::goto_binary_serde::write_goto_binary_file;
-use cbmc::RoundingMode;
+use cbmc::{InternString, RoundingMode};
 use cbmc::{InternedString, MachineModel};
 use kani_metadata::artifact::convert_type;
 use kani_metadata::CompilerArtifactStub;
@@ -32,12 +32,10 @@ use rustc_data_structures::fx::{FxHashMap, FxIndexMap};
 use rustc_data_structures::temp_dir::MaybeTempDir;
 use rustc_errors::{ErrorGuaranteed, DEFAULT_LOCALE_RESOURCE};
 use rustc_hir::def_id::LOCAL_CRATE;
-use rustc_hir::definitions::DefPathHash;
 use rustc_metadata::creader::MetadataLoaderDyn;
 use rustc_metadata::fs::{emit_wrapper_file, METADATA_FILENAME};
 use rustc_metadata::EncodedMetadata;
 use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
-use rustc_middle::mir::mono::MonoItem;
 use rustc_middle::ty::TyCtxt;
 use rustc_middle::util::Providers;
 use rustc_session::config::{CrateType, OutputFilenames, OutputType};
@@ -46,7 +44,7 @@ use rustc_session::Session;
 use rustc_smir::rustc_internal;
 use rustc_target::abi::Endian;
 use rustc_target::spec::PanicStrategy;
-use stable_mir::mir::mono::MonoItem as MonoItemStable;
+use stable_mir::mir::mono::{Instance, MonoItem};
 use stable_mir::CrateDef;
 use std::any::Any;
 use std::collections::BTreeMap;
@@ -82,10 +80,10 @@ impl GotocCodegenBackend {
     fn codegen_items<'tcx>(
         &self,
         tcx: TyCtxt<'tcx>,
-        starting_items: &[MonoItem<'tcx>],
+        starting_items: &[MonoItem],
         symtab_goto: &Path,
         machine_model: &MachineModel,
-    ) -> (GotocCtx<'tcx>, Vec<MonoItem<'tcx>>) {
+    ) -> (GotocCtx<'tcx>, Vec<MonoItem>) {
         let items = with_timer(
             || collect_reachable_items(tcx, starting_items),
             "codegen reachability analysis",
@@ -103,17 +101,13 @@ impl GotocCodegenBackend {
                 for item in &items {
                     match *item {
                         MonoItem::Fn(instance) => {
-                            let instance = rustc_internal::stable(instance);
                             gcx.call_with_panic_debug_info(
                                 |ctx| ctx.declare_function(instance),
                                 format!("declare_function: {}", instance.name()),
                                 instance.def,
                             );
                         }
-                        MonoItem::Static(_) => {
-                            let MonoItemStable::Static(def) = rustc_internal::stable(item) else {
-                                unreachable!()
-                            };
+                        MonoItem::Static(def) => {
                             gcx.call_with_panic_debug_info(
                                 |ctx| ctx.declare_static(def),
                                 format!("declare_static: {}", def.name()),
@@ -128,7 +122,6 @@ impl GotocCodegenBackend {
                 for item in &items {
                     match *item {
                         MonoItem::Fn(instance) => {
-                            let instance = rustc_internal::stable(instance);
                             gcx.call_with_panic_debug_info(
                                 |ctx| ctx.codegen_function(instance),
                                 format!(
@@ -139,10 +132,7 @@ impl GotocCodegenBackend {
                                 instance.def,
                             );
                         }
-                        MonoItem::Static(_) => {
-                            let MonoItemStable::Static(def) = rustc_internal::stable(item) else {
-                                unreachable!()
-                            };
+                        MonoItem::Static(def) => {
                             gcx.call_with_panic_debug_info(
                                 |ctx| ctx.codegen_static(def),
                                 format!("codegen_static: {}", def.name()),
@@ -237,28 +227,31 @@ impl CodegenBackend for GotocCodegenBackend {
                 ReachabilityType::Harnesses => {
                     // Cross-crate collecting of all items that are reachable from the crate harnesses.
                     let harnesses = queries.target_harnesses();
-                    let mut items: HashSet<DefPathHash> = HashSet::with_capacity(harnesses.len());
+                    let mut items: HashSet<_> = HashSet::with_capacity(harnesses.len());
                     items.extend(harnesses);
-                    let harnesses = filter_crate_items(tcx, |_, def_id| {
-                        items.contains(&tcx.def_path_hash(def_id))
+                    let harnesses = filter_crate_items(tcx, |_, instance| {
+                        items.contains(&instance.mangled_name().intern())
                     });
                     for harness in harnesses {
-                        let model_path = queries
-                            .harness_model_path(&tcx.def_path_hash(harness.def_id()))
-                            .unwrap();
-                        let (gcx, items) =
-                            self.codegen_items(tcx, &[harness], model_path, &results.machine_model);
-                        results.extend(gcx, items, None);
+                        let model_path =
+                            queries.harness_model_path(&harness.mangled_name()).unwrap();
+                        let (gcx, mono_items) = self.codegen_items(
+                            tcx,
+                            &[MonoItem::Fn(harness)],
+                            model_path,
+                            &results.machine_model,
+                        );
+                        results.extend(gcx, mono_items, None);
                     }
                 }
                 ReachabilityType::Tests => {
                     // We're iterating over crate items here, so what we have to codegen is the "test description" containing the
                     // test closure that we want to execute
                     // TODO: Refactor this code so we can guarantee that the pair (test_fn, test_desc) actually match.
                     let mut descriptions = vec![];
-                    let harnesses = filter_const_crate_items(tcx, |_, def_id| {
-                        if is_test_harness_description(tcx, def_id) {
-                            descriptions.push(def_id);
+                    let harnesses = filter_const_crate_items(tcx, |_, item| {
+                        if is_test_harness_description(tcx, item.def) {
+                            descriptions.push(item.def);
                             true
                         } else {
                             false
@@ -289,11 +282,15 @@ impl CodegenBackend for GotocCodegenBackend {
                 }
                 ReachabilityType::None => {}
                 ReachabilityType::PubFns => {
-                    let entry_fn = tcx.entry_fn(()).map(|(id, _)| id);
-                    let local_reachable = filter_crate_items(tcx, |_, def_id| {
-                        (tcx.is_reachable_non_generic(def_id) && tcx.def_kind(def_id).is_fn_like())
-                            || entry_fn == Some(def_id)
-                    });
+                    let main_instance =
+                        stable_mir::entry_fn().map(|main_fn| Instance::try_from(main_fn).unwrap());
+                    let local_reachable = filter_crate_items(tcx, |_, instance| {
+                        let def_id = rustc_internal::internal(instance.def.def_id());
+                        Some(instance) == main_instance || tcx.is_reachable_non_generic(def_id)
+                    })
+                    .into_iter()
+                    .map(MonoItem::Fn)
+                    .collect::<Vec<_>>();
                     let model_path = base_filename.with_extension(ArtifactType::SymTabGoto);
                     let (gcx, items) = self.codegen_items(
                         tcx,
@@ -527,17 +524,17 @@ where
     }
 }
 
-struct GotoCodegenResults<'tcx> {
+struct GotoCodegenResults {
     reachability: ReachabilityType,
     harnesses: Vec<HarnessMetadata>,
     unsupported_constructs: UnsupportedConstructs,
     concurrent_constructs: UnsupportedConstructs,
-    items: Vec<MonoItem<'tcx>>,
+    items: Vec<MonoItem>,
     crate_name: InternedString,
     machine_model: MachineModel,
 }
 
-impl<'tcx> GotoCodegenResults<'tcx> {
+impl GotoCodegenResults {
     pub fn new(tcx: TyCtxt, reachability: ReachabilityType) -> Self {
         GotoCodegenResults {
             reachability,
@@ -585,12 +582,7 @@ impl<'tcx> GotoCodegenResults<'tcx> {
         }
     }
 
-    fn extend(
-        &mut self,
-        gcx: GotocCtx,
-        items: Vec<MonoItem<'tcx>>,
-        metadata: Option<HarnessMetadata>,
-    ) {
+    fn extend(&mut self, gcx: GotocCtx, items: Vec<MonoItem>, metadata: Option<HarnessMetadata>) {
         let mut items = items;
         self.harnesses.extend(metadata);
         self.concurrent_constructs.extend(gcx.concurrent_constructs);
@@ -599,7 +591,7 @@ impl<'tcx> GotoCodegenResults<'tcx> {
     }
 
     /// Prints a report at the end of the compilation.
-    fn print_report(&self, tcx: TyCtxt<'tcx>) {
+    fn print_report(&self, tcx: TyCtxt) {
         // Print all unsupported constructs.
         if !self.unsupported_constructs.is_empty() {
             // Sort alphabetically.
@@ -631,7 +623,7 @@ impl<'tcx> GotoCodegenResults<'tcx> {
 
         // Print some compilation stats.
         if tracing::enabled!(tracing::Level::INFO) {
-            analysis::print_stats(tcx, &self.items);
+            analysis::print_stats(&self.items);
         }
     }
 }

kani-compiler/src/codegen_cprover_gotoc/utils/names.rs

@@ -7,11 +7,9 @@ use crate::codegen_cprover_gotoc::GotocCtx;
 use cbmc::InternedString;
 use rustc_hir::def_id::LOCAL_CRATE;
 use rustc_middle::mir::mono::CodegenUnitNameBuilder;
-use rustc_middle::ty::print::with_no_trimmed_paths;
-use rustc_middle::ty::{Instance, TyCtxt};
-use stable_mir::mir::mono::Instance as InstanceStable;
+use rustc_middle::ty::TyCtxt;
+use stable_mir::mir::mono::Instance;
 use stable_mir::mir::Local;
-use tracing::debug;
 
 impl<'tcx> GotocCtx<'tcx> {
     /// The full crate name including versioning info
@@ -52,34 +50,11 @@ impl<'tcx> GotocCtx<'tcx> {
         format!("{var_name}_init")
     }
 
-    /// A human readable name in Rust for reference, should not be used as a key.
-    pub fn readable_instance_name(&self, instance: Instance<'tcx>) -> String {
-        with_no_trimmed_paths!(self.tcx.def_path_str_with_args(instance.def_id(), instance.args))
-    }
-
-    /// The actual function name used in the symbol table
-    pub fn symbol_name(&self, instance: Instance<'tcx>) -> String {
-        let llvm_mangled = self.tcx.symbol_name(instance).name.to_string();
-        debug!(
-            "finding function name for instance: {}, debug: {:?}, name: {}, symbol: {}",
-            instance,
-            instance,
-            self.readable_instance_name(instance),
-            llvm_mangled,
-        );
-
-        let pretty = self.readable_instance_name(instance);
-
-        // Make main function a special case in order to support `--function main`
-        // TODO: Get rid of this: https://github.com/model-checking/kani/issues/2129
-        if pretty == "main" { pretty } else { llvm_mangled }
-    }
-
     /// Return the mangled name to be used in the symbol table.
     ///
     /// We special case main function in order to support `--function main`.
     // TODO: Get rid of this: https://github.com/model-checking/kani/issues/2129
-    pub fn symbol_name_stable(&self, instance: InstanceStable) -> String {
+    pub fn symbol_name_stable(&self, instance: Instance) -> String {
         let pretty = instance.name();
         if pretty == "main" { pretty } else { instance.mangled_name() }
     }