Refactor pretty name to restore passable dyn trait functionality (rust-lang#171)

Author: avanhatt

compiler/rustc_codegen_llvm/src/gotoc/metadata.rs

@@ -17,7 +17,7 @@ use rustc_middle::mir::interpret::Allocation;
 use rustc_middle::mir::{BasicBlock, Body, HasLocalDecls, Local, Operand, Place, Rvalue};
 use rustc_middle::ty::layout::{HasParamEnv, HasTyCtxt, TyAndLayout};
 use rustc_middle::ty::print::with_no_trimmed_paths;
-use rustc_middle::ty::{self, Instance, Ty, TyCtxt, TypeFoldable};
+use rustc_middle::ty::{self, Binder, Instance, TraitRef, Ty, TyCtxt, TypeFoldable};
 use rustc_target::abi::{HasDataLayout, LayoutOf, TargetDataLayout};
 use rustc_target::spec::Target;
 use std::iter;
@@ -186,10 +186,35 @@ impl<'tcx> GotocCtx<'tcx> {
         self.current_fn.as_ref().map(|x| self.symbol_name(x.instance))
     }
 
-    /// a path to the def id. the difference from [instance_name] is that it does not consider generics.
-    pub fn pretty_name(&self, did: DefId) -> String {
-        let def_path = self.tcx.def_path(did);
-        format!("{}{}", self.tcx.crate_name(did.krate), def_path.to_string_no_crate_verbose())
+    /// Pretty name including crate path and trait information. For example:
+    ///    boxtrait_fail::<Concrete as Trait>::increment
+    /// Generated from the fn instance to insert _into_ the symbol table.
+    /// Must match the format of pretty_name_from_dynamic_object.
+    /// TODO: internal unit tests https://github.com/model-checking/rmc/issues/172
+    pub fn pretty_name_from_instance(&self, instance: Instance<'tcx>) -> String {
+        format!(
+            "{}::{}",
+            self.tcx.crate_name(instance.def_id().krate),
+            with_no_trimmed_paths(|| instance.to_string())
+        )
+    }
+
+    /// Pretty name including crate path and trait information. For example:
+    ///    boxtrait_fail::<Concrete as Trait>::increment
+    /// Generated from the dynamic object type for _lookup_ from the symbol table.
+    /// Must match the format of pretty_name_from_instance.
+    pub fn pretty_name_from_dynamic_object(
+        &self,
+        def_id: DefId,
+        trait_ref_t: Binder<'_, TraitRef<'tcx>>,
+    ) -> String {
+        let normalized_object_type_name = self.normalized_name_of_dynamic_object_type(trait_ref_t);
+        format!(
+            "{}::{}::{}",
+            self.tcx.crate_name(def_id.krate),
+            normalized_object_type_name,
+            self.tcx.item_name(def_id)
+        )
     }
 
     /// a human readable name in rust for reference
@@ -208,8 +233,8 @@ impl<'tcx> GotocCtx<'tcx> {
             llvm_mangled,
             rustc_demangle::demangle(&llvm_mangled).to_string()
         );
-        let did = instance.def.def_id();
-        let pretty = self.pretty_name(did);
+
+        let pretty = self.pretty_name_from_instance(instance);
 
         // make main function a special case for easy CBMC entry
         if pretty.ends_with("::main") {

compiler/rustc_codegen_llvm/src/gotoc/mod.rs

@@ -166,7 +166,7 @@ impl<'tcx> GotocCtx<'tcx> {
         self.ensure(&self.fname(), |ctx, fname| {
             let mir = ctx.mir();
             Symbol::function(fname, ctx.fn_typ(), None, ctx.codegen_span2(&mir.span))
-                .with_pretty_name(&ctx.pretty_name(instance.def_id()))
+                .with_pretty_name(&ctx.pretty_name_from_instance(instance))
         });
         self.reset_current_fn();
     }

compiler/rustc_codegen_llvm/src/gotoc/rvalue.rs

@@ -679,10 +679,8 @@ impl<'tcx> GotocCtx<'tcx> {
             .cloned()
             .unwrap();
 
-        // TODO: this name lookup does not work with rust-tests/cbmc-reg/DynTrait/main.rs
-        let normalized_object_type_name = self.normalized_name_of_dynamic_object_type(trait_ref_t);
-        let pretty_function_name = format!("{}::{}", normalized_object_type_name, function_name);
-        let matching_symbols = self.symbol_table.find_by_pretty_name(&pretty_function_name); //("<Rectangle as Vol>::vol");
+        let pretty_function_name = self.pretty_name_from_dynamic_object(def_id, trait_ref_t);
+        let matching_symbols = self.symbol_table.find_by_pretty_name(&pretty_function_name); //("<path>::<Rectangle as Vol>::vol");
         match matching_symbols.len() {
             0 => {
                 warn!(