continued work on new register allocator implementation.

next commit will have it integrated if it works

.zed/tasks.json

@@ -19,6 +19,11 @@
     "command": "cargo run --bin dsx-build",
     "use_new_terminal": true,
   },
+  {
+    "label": "Check All",
+    "command": "cargo clippy --all-targets",
+    "use_new_terminal": false,
+  },
   {
     "label": "Build All (Release)",
     "command": "cargo build --release",

compiler/src/backend/dsa/mod.rs

@@ -4,7 +4,6 @@ mod codegen;
 mod instruction;
 mod registers;
 mod scope;
-mod variable;
 
 pub fn generate_code(ast: &Program) -> Result<String, CompilerError> {
     let mut codegen = codegen::CodeGenerator::new(ast.clone());

compiler/src/backend/dsa/scope.rs

@@ -1,49 +1,211 @@
 use std::{cell::RefCell, collections::HashMap, ops::Deref, rc::Rc};
 
-use uuid::Uuid;
-
 use crate::{
     backend::dsa::{
         instruction::{InsBlock, Instruction},
         registers::{Register, RegisterAllocator},
-        variable::Variable,
     },
-    model::CompilerError,
+    error,
+    model::{CompilerError, Name, TypeId},
 };
 
+/// scope object
+pub struct Scope<'a> {
+    /// outer scope, for a function this will be the global scope.
+    parent: Option<&'a mut Scope<'a>>,
+    alloc: Rc<RefCell<Allocator>>,
+
+    /// is the scope a function body or just a loop?
+    /// depending on the type, ending a scope will have different behaviour
+    r#type: ScopeType,
+
+    /// variables
+    variables: HashMap<String, Variable>,
+
+    entry_stack_offset: i32,
+}
+
+impl<'a> Scope<'a> {
+    pub fn new() -> Scope<'a> {
+        let alloc = Rc::new(RefCell::new(Allocator::new()));
+        let entry_stack_offset = alloc.borrow().get_stack_offset();
+
+        Self {
+            alloc,
+            entry_stack_offset,
+            parent: None,
+            r#type: ScopeType::Function,
+            variables: HashMap::new(),
+        }
+    }
+
+    pub fn new_from(parent: &'a mut Scope<'a>, r#type: ScopeType) -> Scope<'a> {
+        let alloc = Rc::clone(&parent.alloc);
+        let entry_stack_offset = alloc.borrow().get_stack_offset();
+
+        Self {
+            alloc,
+            entry_stack_offset,
+            parent: Some(parent),
+            r#type,
+            variables: HashMap::new(),
+        }
+    }
+
+    pub fn create_var(
+        &mut self,
+        name: String,
+        r#type: TypeId,
+    ) -> Result<(), CompilerError> {
+        let mut var = Variable::new(name, r#type.clone());
+
+        if r#type.size() > 4 {
+            let slot = self.alloc.borrow_mut().allocate_stack_slot(r#type.size());
+            var.stack_slot = Some(slot);
+        } else {
+            let reg = self.alloc.borrow_mut().allocate_var()?;
+            var.register = Some(reg);
+        }
+
+        self.variables.insert(var.name.clone(), var);
+        Ok(())
+    }
+
+    pub fn alloc_temp(&mut self) -> Result<TempReg, CompilerError> {
+        self.alloc.borrow_mut().allocate_temp()
+    }
+
+    pub fn free_temp(&mut self, temp: &TempReg) {
+        self.alloc.borrow_mut().free_temp(temp)
+    }
+
+    pub fn free_var(&mut self, reg: &AssignedReg) {
+        self.alloc.borrow_mut().free_var(reg);
+    }
+
+    pub fn close(&mut self) {
+        // tell the allocator that this scope is closing
+        // this reverts the stack offset to what it was before this scope was created.
+        self.alloc.clone().borrow_mut().destroy_scope(self);
+
+        for var in self.variables.clone().values() {
+            if let Some(reg) = var.register {
+                self.free_var(&reg);
+            }
+        }
+    }
+
+    fn get_var(&mut self, var: &str) -> Option<&mut Variable> {
+        self.variables.get_mut(var)
+    }
+
+    pub fn offset_read(
+        &mut self,
+        var: &str,
+        offset: i32,
+    ) -> Result<(TempReg, Instruction), CompilerError> {
+        if let Some(var) = self.get_var(var) {
+            let slot = var.stack_slot.ok_or_else(|| {
+                error("Attempt to read from a var without a stack slot!")
+            })?;
+
+            return self.alloc.borrow_mut().offset_read(&slot, offset);
+        }
+
+        Err(CompilerError::Undefined(Name::new(var, None)))
+    }
+
+    pub fn offset_write(
+        &mut self,
+        reg: &TempReg,
+        var: &str,
+        offset: i32,
+    ) -> Result<Instruction, CompilerError> {
+        if let Some(var) = self.get_var(var) {
+            let slot = var.stack_slot.ok_or_else(|| {
+                error("Attempt to write to a var without a stack slot!")
+            })?;
+
+            return Ok(self.alloc.borrow_mut().offset_write(reg, &slot, offset));
+        }
+
+        Err(CompilerError::Undefined(Name::new(var, None)))
+    }
+
+    pub fn load_var(
+        &mut self,
+        var: &str,
+    ) -> Result<(AssignedReg, Instruction), CompilerError> {
+        if let Some(v) = self.get_var(var).cloned()
+            && let Some(slot) = v.stack_slot
+        {
+            let res = self.alloc.borrow_mut().load_var(&slot)?;
+            self.get_var(var).unwrap().register = Some(res.0);
+            return Ok(res);
+        }
+
+        panic!("e")
+    }
+
+    pub fn spill_var(&mut self, var: &str) -> Result<Instruction, CompilerError> {
+        if let Some(v) = self.get_var(var).cloned()
+            && let Some(rg) = v.register
+        {
+            let mut slot = v.stack_slot;
+            let res = self.alloc.borrow_mut().spill_var(&rg, &mut slot);
+            self.get_var(var).unwrap().stack_slot = slot;
+            return res;
+        }
+
+        Err(CompilerError::Undefined(Name::new(var, None)))
+    }
+}
+
+impl Drop for Scope<'_> {
+    fn drop(&mut self) {
+        self.close()
+    }
+}
+
+#[derive(PartialEq, Copy, Clone, Debug)]
+pub enum ScopeType {
+    Function,
+    IfBlock,
+    LoopBlock,
+}
+
+#[derive(Clone)]
+pub struct Variable {
+    pub name: String,
+
+    /// the type of the variable.
+    r#type: TypeId,
+
+    /// size taken up in bytes.
+    /// if size > 4, value must be stored on the stack.
+    pub size: usize,
+
+    pub stack_slot: Option<StackSlot>,
+    pub register: Option<AssignedReg>,
+}
+
+impl Variable {
+    pub fn new(name: String, r#type: TypeId) -> Self {
+        Self {
+            name,
+            size: r#type.size(),
+            r#type,
+            stack_slot: None,
+            register: None,
+        }
+    }
+}
+
 pub struct Allocator {
     stack_offset: i32,
     in_use: [(Register, bool); 16],
 }
 
-pub struct TempReg(Register);
-pub struct AssignedReg(Register);
-pub struct StackSlot(i32);
-
-impl Deref for TempReg {
-    type Target = Register;
-
-    fn deref(&self) -> &Self::Target {
-        &self.0
-    }
-}
-
-impl Deref for AssignedReg {
-    type Target = Register;
-
-    fn deref(&self) -> &Self::Target {
-        &self.0
-    }
-}
-
-impl Deref for StackSlot {
-    type Target = i32;
-
-    fn deref(&self) -> &Self::Target {
-        &self.0
-    }
-}
-
 impl Allocator {
     pub fn new() -> Self {
         let mut in_use = [(Register::Null, false); 16];
@@ -64,7 +226,7 @@ impl Allocator {
 
         for var in scope.variables.drain() {
             if let Some(assigned) = var.1.register {
-                self.free_assigned(&assigned);
+                self.free_var(&assigned);
             }
         }
     }
@@ -82,71 +244,74 @@ impl Allocator {
     //
     // - read / write bytes from the stack+offset in a larger variable into a register.
 
-    pub fn read_var(&mut self, var: &mut Variable) -> Result<InsBlock, CompilerError> {
+    pub fn offset_read(
-        if let Some(slot) = &mut var.stack_slot {
+        &mut self,
-            if var.register.is_none() {
+        slot: &StackSlot,
-                var.register = Some(self.allocate_var()?);
+        offset: i32,
+    ) -> Result<(TempReg, Instruction), CompilerError> {
+        let register = self.allocate_temp()?;
+
+        // instruction: reg = *(&var + offset)
+        Ok((
+            register.clone(),
+            Instruction::ldw_reg_offset(
+                Register::Spr,
+                *register,
+                (**slot + offset) - self.stack_offset,
+            ),
+        ))
     }
 
-            if let Some(reg) = &var.register {
+    pub fn offset_write(
-                return Ok(InsBlock::from(Instruction::ldw_reg_offset(
+        &mut self,
+        reg: &TempReg,
+        slot: &StackSlot,
+        offset: i32,
+    ) -> Instruction {
+        // instruction: *(&var + offset) = reg
+        Instruction::stw_reg_offset(
+            **reg,
+            Register::Spr,
+            (**slot + offset) - self.stack_offset,
+        )
+    }
+
+    pub fn load_var(
+        &mut self,
+        slot: &StackSlot,
+    ) -> Result<(AssignedReg, Instruction), CompilerError> {
+        let reg = self.allocate_var()?;
+
+        Ok((
+            reg.clone(),
+            Instruction::ldw_reg_offset(Register::Spr, *reg, **slot - self.stack_offset),
+        ))
+    }
+
+    pub fn spill_var(
+        &mut self,
+        reg: &AssignedReg,
+        slot: &mut Option<StackSlot>,
+        // var: &mut Variable,
+    ) -> Result<Instruction, CompilerError> {
+        if let Some(slot) = &slot {
+            let block = Instruction::stw_reg_offset(
                 **reg,
                 Register::Spr,
                 **slot - self.stack_offset,
-                )));
+            );
-            }
-
-            unreachable!()
-        }
-
-        Err(CompilerError::Generic(format!(
-            "Tried to write var {} to stack but var was not assigned a reg and/or stack slot",
-            var.name
-        )))
-    }
-
-    pub fn write_var(&mut self, var: &mut Variable) -> Result<InsBlock, CompilerError> {
-        if let Some(slot) = &var.stack_slot {
-            if let Some(reg) = &var.register {
-                return Ok(InsBlock::from(Instruction::stw_reg_offset(
-                    **reg,
-                    Register::Spr,
-                    **slot - self.stack_offset,
-                )));
-            }
-        }
-
-        Err(CompilerError::Generic(format!(
-            "Tried to write var {} to stack but var was not assigned a reg and/or stack slot",
-            var.name
-        )))
-    }
-
-    pub fn spill_var(&mut self, var: &mut Variable) -> Result<InsBlock, CompilerError> {
-        if let Some(slot) = &var.stack_slot {
-            let block = self.write_var(var)?;
-            if let Some(reg) = &var.register {
-                self.free_assigned(reg);
-                var.register = None;
-            }
 
+            self.free_var(reg);
             return Ok(block);
         }
 
         // var doesn't have a stack slot so we need to create one
-        if let Some(reg) = &var.register {
+        let new_slot = self.allocate_stack_slot(4); // alloc 4 bytes for reg value.
-            let slot = self.allocate_stack_slot(var.size);
+        let block = Instruction::push(**reg);
-            let block = InsBlock::from(Instruction::push(**reg));
 
-            self.free_assigned(reg);
+        self.free_var(reg);
-            var.register = None;
+        *slot = Some(new_slot);
-            var.stack_slot = Some(slot);
+        Ok(block)
-            return Ok(block);
-        }
-
-        return Err(CompilerError::Generic(
-            "spill_var called on a variable without a register".to_string(),
-        ));
     }
 
     pub fn allocate_stack_slot(&mut self, size: usize) -> StackSlot {
@@ -179,7 +344,7 @@ impl Allocator {
         self.in_use[**temp as usize].1 = false;
     }
 
-    fn free_assigned(&mut self, reg: &AssignedReg) {
+    pub fn free_var(&mut self, reg: &AssignedReg) {
         // frees a register.
         self.in_use[**reg as usize].1 = false;
     }
@@ -197,91 +362,33 @@ impl Allocator {
     }
 }
 
-pub struct FunctionContext {
+#[derive(Clone, Copy, Debug)]
-    name: String,
+pub struct TempReg(Register);
-    allocator: RefCell<Allocator>,
+#[derive(Clone, Copy, Debug)]
-}
+pub struct AssignedReg(Register);
+#[derive(Clone, Copy, Debug)]
+pub struct StackSlot(i32);
 
-impl FunctionContext {
+impl Deref for TempReg {
-    pub fn new(name: String) -> Self {
+    type Target = Register;
-        Self {
-            name,
-            allocator: RefCell::new(Allocator::new()),
-        }
-    }
 
-    pub fn get_stack_offset(&self) -> i32 {
+    fn deref(&self) -> &Self::Target {
-        self.allocator.borrow().get_stack_offset()
+        &self.0
     }
 }
 
-/// scope object
+impl Deref for AssignedReg {
-pub struct Scope<'a> {
+    type Target = Register;
-    /// outer scope, for a function this will be the global scope.
-    parent: Option<&'a mut Scope<'a>>,
 
-    context: Rc<FunctionContext>,
+    fn deref(&self) -> &Self::Target {
-
+        &self.0
-    /// is the scope a function body or just a loop?
-    /// depending on the type, ending a scope will have different behaviour
-    r#type: ScopeType,
-
-    /// variables
-    variables: HashMap<Uuid, Variable>,
-
-    entry_stack_offset: i32,
-}
-
-impl<'a> Scope<'a> {
-    pub fn new(parent: &'a mut Scope<'a>, r#type: ScopeType) -> Scope<'a> {
-        Self {
-            entry_stack_offset: parent.context.get_stack_offset(),
-            context: Rc::clone(&parent.context),
-            parent: Some(parent),
-            r#type,
-            variables: HashMap::new(),
-        }
-    }
-
-    pub fn close(&mut self) -> Result<(), CompilerError> {
-        // closing a scope means we need to drop all variables in scope and free
-        // registers.
-        for (name, var) in self.variables.iter() {
-            todo!()
-            // if let Some(reg) = var.allocated_register {}
-
-            // if let Some(offset) = var.bpr_offset {
-            //     self.stack_offset -= offset;
-            // }
-        }
-
-        Ok(())
-    }
-
-    pub fn alloc_temp_reg(&mut self) -> Result<(Register, InsBlock), CompilerError> {
-        todo!()
-    }
-
-    pub fn alloc_var_reg(&mut self) -> Result<(Register, InsBlock), CompilerError> {
-        todo!()
-    }
-
-    pub fn alloc_var_stack(&mut self) -> Result<(Register, InsBlock), CompilerError> {
-        todo!()
-    }
-
-    pub fn free_var_stack(&mut self) -> Result<(Register, InsBlock), CompilerError> {
-        todo!()
-    }
-
-    pub fn free_temp_reg(&mut self) -> Result<(Register, InsBlock), CompilerError> {
-        todo!()
     }
 }
 
-#[derive(PartialEq, Copy, Clone, Debug)]
+impl Deref for StackSlot {
-pub enum ScopeType {
+    type Target = i32;
-    Function,
+
-    IfBlock,
+    fn deref(&self) -> &Self::Target {
-    LoopBlock,
+        &self.0
+    }
 }

compiler/src/backend/dsa/variable.rs

@@ -1,93 +0,0 @@
-use std::{collections::HashMap, hash::Hash, rc::Rc};
-
-use uuid::Uuid;
-
-use crate::{
-    backend::dsa::{
-        instruction::InsBlock,
-        registers::Register,
-        scope::{AssignedReg, FunctionContext, Scope, StackSlot},
-    },
-    model::{CompilerError, TypeId},
-};
-
-pub struct Variable {
-    pub name: String,
-    pub uuid: Uuid,
-
-    /// the type of the variable.
-    r#type: TypeId,
-
-    /// size taken up in bytes.
-    /// if size > 4, value must be stored on the stack.
-    pub size: usize,
-
-    pub stack_slot: Option<StackSlot>,
-    pub register: Option<AssignedReg>,
-}
-
-impl Variable {
-    pub fn new_uninit(name: String, r#type: TypeId) -> Self {
-        Self {
-            name,
-            uuid: Uuid::new_v4(),
-            size: r#type.size(),
-            r#type,
-            stack_slot: None,
-            register: None,
-        }
-    }
-
-    pub fn new(
-        name: String,
-        r#type: TypeId,
-        scope: &'_ mut Scope,
-    ) -> Result<Self, CompilerError> {
-        let mut var = Self::new_uninit(name, r#type);
-        var.alloc_default(scope);
-
-        Ok(var)
-    }
-
-    fn alloc_default(&mut self, scope: &'_ mut Scope) {
-        if self.size > 4 {
-            self.alloc_stack(scope).unwrap();
-        } else {
-            self.alloc_register(scope).unwrap();
-        }
-    }
-
-    fn alloc_register(
-        &mut self,
-        scope: &'_ mut Scope,
-    ) -> Result<Register, CompilerError> {
-        if self.size > 4 {
-            return Err(CompilerError::Generic(format!(
-                "Type {} cannot be allocated a register as it has a size of {} bytes",
-                self.r#type, self.size
-            )));
-        }
-
-        todo!("integrate with register alloc logic")
-
-        // self.allocated_register = Some(...)
-    }
-
-    fn alloc_stack(&mut self, scope: &'_ mut Scope) -> Result<usize, CompilerError> {
-        todo!("integrate with stack alloc logic")
-
-        // self.bpr_offset = Some(...)
-    }
-
-    pub fn load(&mut self, scope: &'_ mut Scope) -> Result<Register, CompilerError> {
-        todo!("load var from stack to reg (if possible)")
-    }
-
-    pub fn drop(&mut self, scope: &'_ mut Scope) -> Result<(), CompilerError> {
-        Ok(())
-    }
-
-    pub fn spill(&mut self, scope: &'_ mut Scope) -> Result<(), CompilerError> {
-        todo!()
-    }
-}

compiler/src/lib.rs

@@ -4,7 +4,7 @@ use std::path::Path;
 
 use common::logging::log;
 
-use crate::specialised::build_specialised;
+use crate::{model::CompilerError, specialised::build_specialised};
 
 mod backend;
 mod frontend;
@@ -70,3 +70,7 @@ pub fn compile_file(
 
     Ok(())
 }
+
+pub fn error(msg: impl Into<String>) -> CompilerError {
+    CompilerError::Generic(msg.into())
+}