Add code object name to traceback

Author: windelbouwman

vm/src/bytecode.rs

@@ -23,16 +23,22 @@ pub struct CodeObject {
     pub locations: Vec<ast::Location>,
     pub arg_names: Vec<String>,
     pub source_path: Option<String>,
+    pub obj_name: String, // Name of the object that created this code object
 }
 
 impl CodeObject {
-    pub fn new(arg_names: Vec<String>, source_path: Option<String>) -> CodeObject {
+    pub fn new(
+        arg_names: Vec<String>,
+        source_path: Option<String>,
+        obj_name: String,
+    ) -> CodeObject {
         CodeObject {
             instructions: Vec::new(),
             label_map: HashMap::new(),
             locations: Vec::new(),
             arg_names: arg_names,
             source_path: source_path,
+            obj_name: obj_name,
         }
     }
 }

vm/src/compile.rs

@@ -12,6 +12,7 @@ use super::vm::VirtualMachine;
 struct Compiler {
     code_object_stack: Vec<CodeObject>,
     nxt_label: usize,
+    source_path: Option<String>,
     current_source_location: ast::Location,
 }
 
@@ -22,7 +23,8 @@ pub fn compile(
     source_path: Option<String>,
 ) -> Result<PyObjectRef, String> {
     let mut compiler = Compiler::new();
-    compiler.push_new_code_object(source_path);
+    compiler.source_path = source_path.clone();
+    compiler.push_new_code_object(source_path, "<module>".to_string());
     match mode {
         Mode::Exec => match parser::parse_program(source) {
             Ok(ast) => {
@@ -87,13 +89,14 @@ impl Compiler {
         Compiler {
             code_object_stack: Vec::new(),
             nxt_label: 0,
+            source_path: None,
             current_source_location: ast::Location::default(),
         }
     }
 
-    fn push_new_code_object(&mut self, source_path: Option<String>) {
+    fn push_new_code_object(&mut self, source_path: Option<String>, obj_name: String) {
         self.code_object_stack
-            .push(CodeObject::new(Vec::new(), source_path.clone()));
+            .push(CodeObject::new(Vec::new(), source_path.clone(), obj_name));
     }
 
     fn pop_code_object(&mut self) -> CodeObject {
@@ -373,7 +376,11 @@ impl Compiler {
                     });
                 }
 
-                self.code_object_stack.push(CodeObject::new(names, None));
+                self.code_object_stack.push(CodeObject::new(
+                    names,
+                    self.source_path.clone(),
+                    name.clone(),
+                ));
                 self.compile_statements(body);
 
                 // Emit None at end:
@@ -404,8 +411,11 @@ impl Compiler {
             }
             ast::Statement::ClassDef { name, body, args } => {
                 self.emit(Instruction::LoadBuildClass);
-                self.code_object_stack
-                    .push(CodeObject::new(vec![String::from("__locals__")], None));
+                self.code_object_stack.push(CodeObject::new(
+                    vec![String::from("__locals__")],
+                    self.source_path.clone(),
+                    name.clone(),
+                ));
                 self.emit(Instruction::LoadName {
                     name: String::from("__locals__"),
                 });
@@ -769,7 +779,8 @@ impl Compiler {
             ast::Expression::Lambda { args, body } => {
                 self.code_object_stack.push(CodeObject::new(
                     args.iter().map(|(name, _default)| name.clone()).collect(),
-                    None,
+                    self.source_path.clone(),
+                    "<lambda>".to_string(),
                 ));
                 self.compile_expression(body);
                 self.emit(Instruction::ReturnValue);

vm/src/exceptions.rs

@@ -25,7 +25,8 @@ pub fn print_exception(vm: &mut VirtualMachine, exc: &PyObjectRef) {
     if let Some(tb) = exc.get_attr("__traceback__") {
         println!("Traceback (most recent call last):");
         if objtype::isinstance(tb.clone(), vm.ctx.list_type()) {
-            let elements = objlist::get_elements(&tb);
+            let mut elements = objlist::get_elements(&tb);
+            elements.reverse();
             for element in elements {
                 if objtype::isinstance(element.clone(), vm.ctx.tuple_type()) {
                     let element = objtuple::get_elements(&element);
@@ -41,7 +42,13 @@ pub fn print_exception(vm: &mut VirtualMachine, exc: &PyObjectRef) {
                         "<error>".to_string()
                     };
 
-                    println!("  File {}, line {}, in ..", filename, lineno);
+                    let obj_name = if let Ok(x) = vm.to_str(element[2].clone()) {
+                        objstr::get_value(&x)
+                    } else {
+                        "<error>".to_string()
+                    };
+
+                    println!("  File {}, line {}, in {}", filename, lineno, obj_name);
                 } else {
                     println!("  File ??");
                 }

vm/src/vm.rs

@@ -243,6 +243,9 @@ impl VirtualMachine {
             "<unknown>".to_string()
         };
 
+        // This is the name of the object being run:
+        let run_obj_name = &self.current_frame().code.obj_name.to_string();
+
         // Execute until return or exception:
         let value = loop {
             let lineno = self.get_lineno();
@@ -266,6 +269,7 @@ impl VirtualMachine {
                     let pos = self.ctx.new_tuple(vec![
                         self.ctx.new_str(filename.clone()),
                         self.ctx.new_int(lineno.get_row() as i32),
+                        self.ctx.new_str(run_obj_name.clone()),
                     ]);
                     objlist::append(
                         self,