Add stack offset propagation, clean up some deprecated things.

dm/src/main.rs

@@ -64,16 +64,14 @@ fn main() {
         }
     }
 
-    for ir_function in &mut ir_functions {
-        ir_function.assign_registers(args.register_count);
-    }
-
+    let mut functions: Vec<Function> = vec![];
     let mut constants_table = ConstantsTable::new();
 
-    let functions: Vec<Function> = ir_functions
-        .iter()
-        .map(|ir_function| ir_function.assemble(&mut constants_table))
-        .collect();
+    for ir_function in &mut ir_functions {
+        let (_, stack_size) = ir_function.assign_registers(args.register_count);
+        let function = ir_function.assemble(stack_size, &mut constants_table);
+        functions.push(function);
+    }
 
     if args.show_asm {
         for function in &functions {

dmc-lib/src/ast/function.rs

@@ -87,14 +87,9 @@ impl Function {
         // handle parameters
         symbol_table.push_scope(&format!("parameter_scope({})", self.declared_name));
         let mut parameter_symbols = vec![];
-        let parameter_count = self.parameters.len();
-        let stack_frame_offset_base = (parameter_count as isize).neg();
-        for (i, parameter) in self.parameters.iter_mut().enumerate() {
+        for parameter in &mut self.parameters {
             match parameter.gather_declared_names(symbol_table) {
                 Ok(parameter_symbol) => {
-                    parameter_symbol
-                        .borrow_mut()
-                        .set_stack_frame_offset(stack_frame_offset_base + (i as isize));
                     parameter_symbols.push(parameter_symbol);
                 }
                 Err(mut parameter_diagnostics) => {

dmc-lib/src/ir/ir_add.rs

@@ -1,7 +1,7 @@
 use crate::constants_table::ConstantsTable;
 use crate::ir::ir_expression::IrExpression;
 use crate::ir::ir_variable::IrVrVariableDescriptor;
-use crate::ir::register_allocation::VrUser;
+use crate::ir::register_allocation::{OffsetCounter, VrUser};
 use dvm_lib::instruction::AddOperand;
 use std::collections::{HashMap, HashSet};
 use std::fmt::{Display, Formatter};
@@ -68,4 +68,8 @@ impl VrUser for IrAdd {
         self.left.propagate_register_assignments(assignments);
         self.right.propagate_register_assignments(assignments);
     }
+
+    fn propagate_stack_offsets(&mut self, _counter: &mut OffsetCounter) {
+        // no-op, no definitions here
+    }
 }

dmc-lib/src/ir/ir_assign.rs

@@ -2,7 +2,7 @@ use crate::constants_table::ConstantsTable;
 use crate::ir::assemble::{Assemble, InstructionsBuilder};
 use crate::ir::ir_operation::IrOperation;
 use crate::ir::ir_variable::{IrVariable, IrVariableDescriptor, IrVrVariableDescriptor};
-use crate::ir::register_allocation::VrUser;
+use crate::ir::register_allocation::{OffsetCounter, VrUser};
 use dvm_lib::instruction::{Instruction, Location};
 use std::cell::RefCell;
 use std::collections::{HashMap, HashSet};
@@ -68,6 +68,13 @@ impl VrUser for IrAssign {
         }
         self.initializer.propagate_register_assignments(assignments);
     }
+
+    fn propagate_stack_offsets(&mut self, counter: &mut OffsetCounter) {
+        let mut borrowed_destination = self.destination.borrow_mut();
+        if let IrVariableDescriptor::Stack(stack_variable) = borrowed_destination.descriptor_mut() {
+            stack_variable.set_offset(counter.next());
+        }
+    }
 }
 
 impl Assemble for IrAssign {

dmc-lib/src/ir/ir_block.rs

@@ -2,7 +2,7 @@ use crate::constants_table::ConstantsTable;
 use crate::ir::assemble::{Assemble, InstructionsBuilder};
 use crate::ir::ir_statement::IrStatement;
 use crate::ir::ir_variable::IrVrVariableDescriptor;
-use crate::ir::register_allocation::{HasVrUsers, VrUser};
+use crate::ir::register_allocation::{HasVrUsers, OffsetCounter, VrUser};
 use std::cell::RefCell;
 use std::collections::{HashMap, HashSet};
 use std::fmt::{Display, Formatter};
@@ -75,6 +75,12 @@ impl VrUser for IrBlock {
             statement.propagate_register_assignments(assignments);
         }
     }
+
+    fn propagate_stack_offsets(&mut self, counter: &mut OffsetCounter) {
+        for statement in &mut self.statements {
+            statement.propagate_stack_offsets(counter);
+        }
+    }
 }
 
 impl Assemble for IrBlock {
@@ -145,7 +151,7 @@ mod tests {
 
         if let ModuleLevelDeclaration::Function(main) = main {
             let mut main_ir = main.to_ir(&symbol_table);
-            let register_assignments = main_ir.assign_registers(2);
+            let (register_assignments, _) = main_ir.assign_registers(2);
             assert_eq!(register_assignments.len(), 4);
         } else {
             unreachable!()

dmc-lib/src/ir/ir_call.rs

@@ -2,7 +2,7 @@ use crate::constants_table::ConstantsTable;
 use crate::ir::assemble::{Assemble, InstructionsBuilder};
 use crate::ir::ir_expression::IrExpression;
 use crate::ir::ir_variable::IrVrVariableDescriptor;
-use crate::ir::register_allocation::VrUser;
+use crate::ir::register_allocation::{OffsetCounter, VrUser};
 use crate::symbol::FunctionSymbol;
 use dvm_lib::instruction::Instruction;
 use std::cell::RefCell;
@@ -53,6 +53,10 @@ impl VrUser for IrCall {
             argument.propagate_register_assignments(assignments);
         }
     }
+
+    fn propagate_stack_offsets(&mut self, _counter: &mut OffsetCounter) {
+        // no-op, because no definitions here
+    }
 }
 
 impl Assemble for IrCall {
@@ -74,7 +78,6 @@ impl Assemble for IrCall {
                 symbol.parameters().len(),
             ));
         }
-        // todo: handle function postlude
     }
 }
 

dmc-lib/src/ir/ir_expression.rs

@@ -3,7 +3,7 @@ use crate::ir::ir_parameter::IrParameter;
 use crate::ir::ir_variable::{
     IrStackVariableDescriptor, IrVariable, IrVariableDescriptor, IrVrVariableDescriptor,
 };
-use crate::ir::register_allocation::VrUser;
+use crate::ir::register_allocation::{OffsetCounter, VrUser};
 use crate::type_info::TypeInfo;
 use dvm_lib::instruction::{AddOperand, Location, MoveOperand, PushOperand, ReturnOperand};
 use std::cell::RefCell;
@@ -225,4 +225,8 @@ impl VrUser for IrExpression {
             }
         }
     }
+
+    fn propagate_stack_offsets(&mut self, _counter: &mut OffsetCounter) {
+        // no-op
+    }
 }

dmc-lib/src/ir/ir_function.rs

@@ -34,21 +34,21 @@ impl IrFunction {
         }
     }
 
-    /// Returns the register assignments for debugging purposes
     pub fn assign_registers(
         &mut self,
         register_count: usize,
-    ) -> HashMap<IrVrVariableDescriptor, usize> {
+    ) -> (HashMap<IrVrVariableDescriptor, usize>, isize) {
         self.entry.borrow_mut().assign_registers(register_count)
     }
 
-    pub fn assemble(&self, constants_table: &mut ConstantsTable) -> Function {
+    pub fn assemble(&self, stack_size: isize, constants_table: &mut ConstantsTable) -> Function {
         let mut builder = InstructionsBuilder::new();
         self.entry.borrow().assemble(&mut builder, constants_table);
         let instructions = builder.take_instructions();
         Function::new(
             self.function_symbol.borrow().name_owned(),
             self.parameters.len(),
+            stack_size,
             instructions,
         )
     }

dmc-lib/src/ir/ir_operation.rs

@@ -2,7 +2,7 @@ use crate::ir::ir_add::IrAdd;
 use crate::ir::ir_call::IrCall;
 use crate::ir::ir_expression::IrExpression;
 use crate::ir::ir_variable::IrVrVariableDescriptor;
-use crate::ir::register_allocation::VrUser;
+use crate::ir::register_allocation::{OffsetCounter, VrUser};
 use std::collections::{HashMap, HashSet};
 use std::fmt::{Display, Formatter};
 
@@ -75,4 +75,8 @@ impl VrUser for IrOperation {
             }
         }
     }
+
+    fn propagate_stack_offsets(&mut self, _counter: &mut OffsetCounter) {
+        // no-op
+    }
 }

dmc-lib/src/ir/ir_return.rs

@@ -2,7 +2,7 @@ use crate::constants_table::ConstantsTable;
 use crate::ir::assemble::{Assemble, InstructionsBuilder};
 use crate::ir::ir_expression::IrExpression;
 use crate::ir::ir_variable::IrVrVariableDescriptor;
-use crate::ir::register_allocation::VrUser;
+use crate::ir::register_allocation::{OffsetCounter, VrUser};
 use dvm_lib::instruction::Instruction;
 use std::collections::{HashMap, HashSet};
 use std::fmt::{Display, Formatter};
@@ -44,10 +44,14 @@ impl VrUser for IrReturn {
             ir_expression.propagate_register_assignments(assignments);
         }
     }
+
+    fn propagate_stack_offsets(&mut self, _counter: &mut OffsetCounter) {
+        // no-op
+    }
 }
 
 impl Assemble for IrReturn {
-    fn assemble(&self, builder: &mut InstructionsBuilder, constants_table: &mut ConstantsTable) {
+    fn assemble(&self, builder: &mut InstructionsBuilder, _constants_table: &mut ConstantsTable) {
         if let Some(ir_expression) = self.value.as_ref() {
             builder.push(Instruction::SetReturnValue(ir_expression.return_operand()));
         }

dmc-lib/src/ir/ir_statement.rs

@@ -4,7 +4,7 @@ use crate::ir::ir_assign::IrAssign;
 use crate::ir::ir_call::IrCall;
 use crate::ir::ir_return::IrReturn;
 use crate::ir::ir_variable::IrVrVariableDescriptor;
-use crate::ir::register_allocation::VrUser;
+use crate::ir::register_allocation::{OffsetCounter, VrUser};
 use std::collections::{HashMap, HashSet};
 use std::fmt::{Display, Formatter};
 
@@ -61,6 +61,20 @@ impl VrUser for IrStatement {
             }
         }
     }
+
+    fn propagate_stack_offsets(&mut self, counter: &mut OffsetCounter) {
+        match self {
+            IrStatement::Assign(ir_assign) => {
+                ir_assign.propagate_stack_offsets(counter);
+            }
+            IrStatement::Call(ir_call) => {
+                ir_call.propagate_stack_offsets(counter);
+            }
+            IrStatement::Return(ir_return) => {
+                ir_return.propagate_stack_offsets(counter);
+            }
+        }
+    }
 }
 
 impl Assemble for IrStatement {

dmc-lib/src/ir/ir_variable.rs

@@ -139,6 +139,10 @@ impl IrStackVariableDescriptor {
         &self.name
     }
 
+    pub fn set_offset(&mut self, offset: isize) {
+        self.offset = Some(offset);
+    }
+
     pub fn offset(&self) -> isize {
         self.offset.unwrap()
     }
@@ -146,6 +150,6 @@ impl IrStackVariableDescriptor {
 
 impl Display for IrStackVariableDescriptor {
     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
-        write!(f, "{}_b{}", self.name, self.block_id)
+        write!(f, "{}_{}", self.name, self.block_id)
     }
 }

dmc-lib/src/ir/register_allocation.rs

@@ -104,7 +104,7 @@ pub trait HasVrUsers {
     fn assign_registers(
         &mut self,
         register_count: usize,
-    ) -> HashMap<IrVrVariableDescriptor, usize> {
+    ) -> (HashMap<IrVrVariableDescriptor, usize>, isize) {
         let mut spills: HashSet<IrVrVariableDescriptor> = HashSet::new();
         loop {
             let mut interference_graph = self.interference_graph();
@@ -122,7 +122,13 @@ pub trait HasVrUsers {
                 for vr_user in self.vr_users_mut() {
                     vr_user.propagate_register_assignments(&registers);
                 }
-                return registers;
+                // also set offsets
+                let mut offset_counter = OffsetCounter::new();
+                for vr_user in self.vr_users_mut() {
+                    vr_user.propagate_stack_offsets(&mut offset_counter);
+                }
+
+                return (registers, offset_counter.get_count());
             }
         }
     }
@@ -136,6 +142,27 @@ pub trait VrUser {
         &mut self,
         assignments: &HashMap<IrVrVariableDescriptor, usize>,
     );
+    fn propagate_stack_offsets(&mut self, counter: &mut OffsetCounter);
+}
+
+pub struct OffsetCounter {
+    counter: isize,
+}
+
+impl OffsetCounter {
+    pub fn new() -> Self {
+        Self { counter: 0 }
+    }
+
+    pub fn next(&mut self) -> isize {
+        let offset = self.counter;
+        self.counter += 1;
+        offset
+    }
+
+    pub fn get_count(&self) -> isize {
+        self.counter
+    }
 }
 
 #[derive(Debug)]

dmc-lib/src/symbol.rs

@@ -51,9 +51,6 @@ pub struct ParameterSymbol {
     name: Rc<str>,
     type_info: TypeInfo,
     ir_parameter: Option<Rc<IrParameter>>,
-
-    #[deprecated]
-    stack_frame_offset: Option<isize>,
 }
 
 impl ParameterSymbol {
@@ -62,7 +59,6 @@ impl ParameterSymbol {
             name: name.into(),
             type_info,
             ir_parameter: None,
-            stack_frame_offset: None,
         }
     }
 
@@ -85,25 +81,12 @@ impl ParameterSymbol {
     pub fn ir_parameter(&self) -> &Rc<IrParameter> {
         self.ir_parameter.as_ref().unwrap()
     }
-
-    #[deprecated]
-    pub fn set_stack_frame_offset(&mut self, offset: isize) {
-        self.stack_frame_offset = Some(offset);
-    }
-
-    #[deprecated]
-    pub fn stack_frame_offset(&self) -> isize {
-        self.stack_frame_offset.unwrap()
-    }
 }
 
 pub struct VariableSymbol {
     name: Rc<str>,
     type_info: Option<TypeInfo>,
     vr_variable: Option<Rc<RefCell<IrVariable>>>,
-
-    #[deprecated]
-    register: Option<usize>,
 }
 
 impl VariableSymbol {
@@ -112,7 +95,6 @@ impl VariableSymbol {
             name: name.into(),
             type_info: None,
             vr_variable: None,
-            register: None,
         }
     }
 
@@ -143,14 +125,6 @@ impl VariableSymbol {
             .as_ref()
             .expect("ir_variable not yet initialized")
     }
-
-    pub fn set_register(&mut self, register: usize) {
-        self.register = Some(register);
-    }
-
-    pub fn register(&self) -> usize {
-        self.register.unwrap()
-    }
 }
 
 pub enum ExpressibleSymbol {

dvm-lib/src/instruction.rs

@@ -72,7 +72,7 @@ impl Display for Location {
                 write!(f, "r{}", register)
             }
             Location::StackFrameOffset(offset) => {
-                if offset.is_positive() {
+                if offset.is_positive() || *offset == 0 {
                     write!(f, "fp+{}", offset)
                 } else {
                     write!(f, "fp{}", offset)

dvm-lib/src/vm/function.rs

@@ -5,14 +5,21 @@ use std::rc::Rc;
 pub struct Function {
     name: Rc<str>,
     parameter_count: usize,
+    stack_size: isize,
     instructions: Vec<Instruction>,
 }
 
 impl Function {
-    pub fn new(name: Rc<str>, parameter_count: usize, instructions: Vec<Instruction>) -> Self {
+    pub fn new(
+        name: Rc<str>,
+        parameter_count: usize,
+        stack_size: isize,
+        instructions: Vec<Instruction>,
+    ) -> Self {
         Self {
             name,
             parameter_count,
+            stack_size,
             instructions,
         }
     }
@@ -29,6 +36,10 @@ impl Function {
         self.parameter_count
     }
 
+    pub fn stack_size(&self) -> isize {
+        self.stack_size
+    }
+
     pub fn instructions(&self) -> &Vec<Instruction> {
         &self.instructions
     }

dvm-lib/src/vm/mod.rs

@@ -234,10 +234,16 @@ pub fn call<'a>(
     call_stack.push(CallFrame::new(function));
 
     // put each arg on the stack
-    for argument in arguments {
-        call_stack.top_mut().stack_mut().push(argument);
+    for argument in &arguments {
+        call_stack.top_mut().stack_mut().push(argument.clone());
     }
 
+    // ensure enough stack space
+    call_stack.top_mut().stack_mut().resize(
+        arguments.len() + (function.stack_size() as usize),
+        Value::Null,
+    );
+
     while call_stack.maybe_top().is_some()
         && call_stack.top().ip() < call_stack.top().instructions().len()
     {
@@ -314,6 +320,12 @@ pub fn call<'a>(
                 // push args
                 call_stack.top_mut().stack_mut().append(&mut args);
 
+                // ensure enough stack space
+                call_stack
+                    .top_mut()
+                    .stack_mut()
+                    .resize(arg_count + (function.stack_size() as usize), Value::Null);
+
                 // set fp for callee frame
                 let callee_frame = call_stack.top_mut();
                 callee_frame.set_fp(*arg_count);