updated compiler to support multiple frontends and backends

This commit is contained in:
2026-02-05 01:09:14 +00:00
parent 8d130a870c
commit a35cfbe864
14 changed files with 1737 additions and 324 deletions
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use std::collections::HashMap;
use std::sync::atomic::AtomicU32;
use std::time::SystemTime;
use chrono::{DateTime, Local};
use super::registers::RegisterAllocator;
use crate::{block, comment, dsa};
use crate::model::{
BinaryOperator, CompilerError, ConstExpr, Declaration, Dependency, Expression,
Program, Statement, UnaryOperator, Variable,
};
pub struct CodeGenerator {
ast: Program,
imports: HashMap<String, String>,
globals: Vec<String>,
functions: Vec<String>,
symbols: Vec<String>,
allocator: RegisterAllocator,
}
fn import(name: &str, path: &str) -> String {
format!("include {name}: \"{}\"", path)
}
impl CodeGenerator {
const RET: &'static str = "\tjmp _ret";
pub fn new(ast: Program) -> Self {
CodeGenerator {
ast,
imports: HashMap::new(),
globals: Vec::new(),
functions: Vec::new(),
symbols: Vec::new(),
allocator: RegisterAllocator::new(),
}
}
pub fn include(&mut self, name: &str, path: &str) {
self.imports.insert(name.to_string(), path.to_string());
}
fn is_global(&self, name: &str) -> bool {
// Check if this variable is in the globals list
self.globals
.iter()
.any(|g| g.contains(&format!("dw {}:", name)))
}
pub fn generate(&mut self) -> Result<String, CompilerError> {
// always include the print library for debugging!
self.include("print", "./lib/io/print.dsa");
for block in self.ast.clone().declarations {
match block {
Declaration::Variable {
var: Variable { name, .. },
..
} => self.symbols.push(name),
Declaration::Function { name, .. } => self.symbols.push(name),
Declaration::Dependency(Dependency { name, .. }) => {
self.symbols.push(name)
}
}
}
for block in self.ast.clone().declarations {
self.generate_block(block.clone())?;
}
self.generate_layout()
}
fn generate_layout(&mut self) -> Result<String, CompilerError> {
let datetime: DateTime<Local> = SystemTime::now().into();
Ok(dsa![
"",
comment!("GENERATED BY DSC COMPILER"),
comment!(format!(
"Generated at {}",
datetime.format("%Y-%m-%d %H:%M:%S")
)),
"",
// imports
comment!("Imports"),
self.imports
.iter()
.map(|(k, v)| import(k, v))
.collect::<Vec<String>>()
.join("\n"),
"",
// reserved memory
comment!("Globals & Reserved Memory"),
self.globals.join("\n"),
"",
// entry point
comment!("Entry Point"),
"dw stack: 0x10000",
"db message: \"Process Exited with code:\"",
block! [ "_init"
dsa![ldw stack, bpr],
dsa![mov bpr, spr],
dsa![push zero],
dsa![call main],
dsa![call print::print_newline],
dsa![lwi message, rg0],
dsa![push rg0],
dsa![call print::print],
dsa![pop zero],
dsa![call print::print_hex_word],
dsa![pop zero],
dsa![hlt]
],
"",
comment!("Return"),
block! [ "_ret"
dsa![mov bpr, spr],
dsa![pop bpr],
dsa![return]
],
comment!("Compiled Code Starts..."),
// block! [ "main"
// dsa![push bpr],
// dsa![mov spr, bpr],
// dsa![lwi 67, rg1],
// dsa![stw rg1, spr, 8],
// dsa![mov bpr, spr],
// dsa![pop bpr],
// dsa![return]
// ],
self.functions.join("\n"),
])
}
fn generate_global(&mut self, name: &str, init: Option<ConstExpr>) {
self.globals.push(format!(
"dw {}: {}",
name,
init.unwrap_or(ConstExpr::Number(0))
))
}
fn generate_block(&mut self, block: Declaration) -> Result<(), CompilerError> {
match block {
Declaration::Variable { var, init, .. } => {
self.generate_global(&var.name, init)
}
Declaration::Function {
name, params, body, ..
} => {
let func = self.generate_function(&name, &params, &body).join("\n");
self.functions.push(format!("{func}\n"));
}
Declaration::Dependency(Dependency { name, path }) => {
self.imports.insert(name, path);
}
};
Ok(())
}
// Example: Generate code for a function
fn generate_function(
&mut self,
name: &str,
params: &[Variable],
body: &[Statement],
) -> Vec<String> {
let mut code = Vec::new();
// Reset allocator for new function
self.allocator.reset();
// Function prologue
code.push(format!("{}:", name));
code.push("\tpush bpr".to_string());
code.push("\tmov spr, bpr".to_string());
code.push(String::new());
// Allocate parameters to registers or stack locations
for (i, param) in params.iter().enumerate() {
let offset = 8 + (i as i32 * 4); // Parameters start at bpr+8
// Track that this parameter is at a stack location
let (reg, load_code) = self.allocator.alloc_var(&param.name).unwrap();
code.extend(load_code);
code.push(format!("\tldw bpr, {}, {}", reg, offset));
}
// Generate code for function body
for stmt in body {
let stmt_code = self.generate_statement(stmt).unwrap();
code.extend(stmt_code);
}
// automatically return at function end
if let Some(x) = code.last()
&& x == Self::RET
{
} else {
code.push(Self::RET.to_string());
}
code
}
// Example: Generate code for a statement
fn generate_statement(
&mut self,
stmt: &Statement,
) -> Result<Vec<String>, CompilerError> {
let mut code = Vec::new();
match stmt {
Statement::Declaration { var, value } => {
if let Some(expr) = value {
// Evaluate expression
let (result_reg, expr_code) = self.generate_expression(expr, true)?;
code.extend(expr_code);
// Store result in variable
let store_code = self.allocator.store_var(&var.name, &result_reg);
code.extend(store_code);
// Free temporary register
self.allocator.free_temp(&result_reg);
} else {
// Just declaring variable without initialization
self.allocator.alloc_var(&var.name)?;
}
}
Statement::Break => unimplemented!(),
Statement::Continue => unimplemented!(),
Statement::PtrWrite { ptr, value } => {
let (result_reg, expr_code) = self.generate_expression(value, true)?;
code.extend(expr_code);
let (ptr_reg, ptr_code) = self.generate_expression(ptr, true)?;
code.extend(ptr_code);
code.push(format!("\tstw {}, {}", result_reg, ptr_reg));
self.allocator.free_temp(&result_reg);
self.allocator.free_temp(&ptr_reg);
}
Statement::Assign { varname, value } => {
// Evaluate expression
let (result_reg, expr_code) = self.generate_expression(value, true)?;
code.extend(expr_code);
// Check if this is a global variable
if self.is_global(varname) {
// Store to global label
code.push(format!("\tstw {}, {}", result_reg, varname));
} else {
// Store result in local variable
let store_code = self.allocator.store_var(varname, &result_reg);
code.extend(store_code);
}
// Free temporary register
self.allocator.free_temp(&result_reg);
}
Statement::Return(expr) => {
if let Some(e) = expr {
let (result_reg, expr_code) = self.generate_expression(e, true)?;
code.extend(expr_code);
code.push(format!("\tstw {}, bpr, 8", result_reg));
code.push(format!("\tjmp _ret"));
self.allocator.free_temp(&result_reg);
}
}
Statement::If {
condition,
then_stmt,
else_stmt,
} => {
// Generate condition
let (cond_reg, cond_code) = self.generate_expression(condition, true)?;
code.extend(cond_code);
// Compare with zero
code.push(format!("\tcmp {}, zero", cond_reg));
self.allocator.free_temp(&cond_reg);
// Generate unique labels
let then_label = format!("_then_{}", self.get_unique_label());
let else_label = format!("_else_{}", self.get_unique_label());
let end_label = format!("_end_{}", self.get_unique_label());
// Jump to else if condition is false (equal to zero)
code.push(format!("\tjeq {}", else_label));
// Then block
code.push(format!("{}:", then_label));
for s in then_stmt {
code.extend(self.generate_statement(s)?);
}
if then_stmt.len() == 0 {
code.push("\tnop".to_string());
}
code.push(format!("\tjmp {}", end_label));
// Else block
code.push(format!("{}:", else_label));
for s in else_stmt {
code.extend(self.generate_statement(s)?);
}
if else_stmt.len() == 0 {
code.push("\tnop".to_string());
}
code.push(format!("{}:", end_label));
}
Statement::While { condition, body } => {
let loop_start = format!("_while_start_{}", self.get_unique_label());
let loop_end = format!("_while_end_{}", self.get_unique_label());
code.push(format!("{}:", loop_start));
// Generate condition
let (cond_reg, cond_code) = self.generate_expression(condition, true)?;
code.extend(cond_code);
code.push(format!("\tcmp {}, zero", cond_reg));
self.allocator.free_temp(&cond_reg);
code.push(format!("\tjeq {}", loop_end));
// Loop body
for s in body {
code.extend(self.generate_statement(s)?);
}
code.push(format!("\tjmp {}", loop_start));
code.push(format!("{}:", loop_end));
}
Statement::Loop(body) => {
let loop_start = format!("_loop_start_{}", self.get_unique_label());
code.push(format!("{}:", loop_start));
for s in body {
code.extend(self.generate_statement(s)?);
}
code.push(format!("\tjmp {}", loop_start));
}
Statement::Expression { expr } => {
let (result_reg, expr_code) = self.generate_expression(expr, false)?;
code.extend(expr_code);
self.allocator.free_temp(&result_reg);
}
Statement::Block(statements) => {
for s in statements {
code.extend(self.generate_statement(s)?);
}
}
}
Ok(code)
}
// Example: Generate code for an expression
// Returns (register containing result, assembly code)
fn generate_expression(
&mut self,
expr: &Expression,
use_result: bool,
) -> Result<(String, Vec<String>), CompilerError> {
let mut code = Vec::new();
// optimisation to prevent generating dead code!
if expr.is_pure() && !use_result {
return Ok((String::new(), code));
}
match expr {
Expression::StringLiteral(value) => {
let (reg, alloc_code) = self.allocator.alloc_temp()?;
code.extend(alloc_code);
// write string into memory
let uuid = self.get_unique_label();
code.push(format!("\tdb str_{uuid}: \"{value}\""));
// Load pointer to string
code.push(format!("\tlwi str_{uuid}, {reg}"));
Ok((reg, code))
}
Expression::CharLiteral(value) => {
let (reg, alloc_code) = self.allocator.alloc_temp()?;
code.extend(alloc_code);
// Load immediate value
code.push(format!("\tlli {}, {} // '{value}'", *value as u8, reg));
Ok((reg, code))
}
Expression::Number(value) => {
let (reg, alloc_code) = self.allocator.alloc_temp()?;
code.extend(alloc_code);
// Load immediate value
code.push(format!("\tlli {}, {}", value & 0xFFFF, reg));
if *value > 0xFFFF || *value < 0 {
code.push(format!("\tlui {}, {}", (value >> 16) & 0xFFFF, reg));
}
Ok((reg, code))
}
Expression::Variable { name, .. } => {
if self.is_global(&name.name) {
// Allocate a temporary register for the global
let (reg, alloc_code) = self.allocator.alloc_temp()?;
code.extend(alloc_code);
// Load from global label
code.push(format!("\tldw {}, {}", name.name, reg));
Ok((reg, code))
} else {
// Local variable - use existing allocator logic
let (reg, load_code) = self.allocator.load_var(&name.name)?;
code.extend(load_code);
Ok((reg, code))
}
}
Expression::Binary { op, left, right } => {
// Evaluate left operand
let (left_reg, left_code) = self.generate_expression(left, true)?;
code.extend(left_code);
// Evaluate right operand
let (right_reg, right_code) = self.generate_expression(right, true)?;
code.extend(right_code);
// Allocate result register
let (result_reg, result_alloc) = self.allocator.alloc_temp()?;
code.extend(result_alloc);
// Generate operation
match op {
BinaryOperator::Add => {
code.push(format!(
"\tadd {}, {}, {}",
left_reg, right_reg, result_reg
));
}
BinaryOperator::Sub => {
code.push(format!(
"\tsub {}, {}, {}",
left_reg, right_reg, result_reg
));
}
BinaryOperator::Mul => {
self.include("maths", "./lib/maths/core.dsa");
// Call multiply function
code.push(format!("\tpush {}", right_reg));
code.push(format!("\tpush {}", left_reg));
code.push("\tcall maths::multiply".to_string());
code.push(format!("\tpop {}", result_reg));
code.push("\tpop zero".to_string());
}
// Comparison operators - return 1 (true) or 0 (false)
BinaryOperator::Eq => {
code.push(format!("\tcmp {}, {}", left_reg, right_reg));
code.push(format!("\tlli 0, {}", result_reg));
let end_label = format!("_cmp_end_{}", self.get_unique_label());
code.push(format!("\tjne {}", end_label)); // If not equal, skip setting to 1
code.push(format!("\tlli 1, {}", result_reg));
code.push(format!("{}:", end_label));
}
BinaryOperator::Ne => {
code.push(format!("\tcmp {}, {}", left_reg, right_reg));
code.push(format!("\tlli 0, {}", result_reg));
let end_label = format!("_cmp_end_{}", self.get_unique_label());
code.push(format!("\tjeq {}", end_label)); // If equal, skip setting to 1
code.push(format!("\tlli 1, {}", result_reg));
code.push(format!("{}:", end_label));
}
BinaryOperator::Lt => {
code.push(format!("\tcmp {}, {}", left_reg, right_reg));
code.push(format!("\tlli 0, {}", result_reg));
let end_label = format!("_cmp_end_{}", self.get_unique_label());
code.push(format!("\tjge {}", end_label)); // If greater or equal, skip setting to 1
code.push(format!("\tlli 1, {}", result_reg));
code.push(format!("{}:", end_label));
}
BinaryOperator::Le => {
code.push(format!("\tcmp {}, {}", left_reg, right_reg));
code.push(format!("\tlli 0, {}", result_reg));
let end_label = format!("_cmp_end_{}", self.get_unique_label());
code.push(format!("\tjgt {}", end_label)); // If greater than, skip setting to 1
code.push(format!("\tlli 1, {}", result_reg));
code.push(format!("{}:", end_label));
}
BinaryOperator::Gt => {
code.push(format!("\tcmp {}, {}", left_reg, right_reg));
code.push(format!("\tlli 0, {}", result_reg));
let end_label = format!("_cmp_end_{}", self.get_unique_label());
code.push(format!("\tjle {}", end_label)); // If less or equal, skip setting to 1
code.push(format!("\tlli 1, {}", result_reg));
code.push(format!("{}:", end_label));
}
BinaryOperator::Ge => {
code.push(format!("\tcmp {}, {}", left_reg, right_reg));
code.push(format!("\tlli 0, {}", result_reg));
let end_label = format!("_cmp_end_{}", self.get_unique_label());
code.push(format!("\tjlt {}", end_label)); // If less than, skip setting to 1
code.push(format!("\tlli 1, {}", result_reg));
code.push(format!("{}:", end_label));
}
_ => unimplemented!(),
}
// Free operand registers (allocator will protect variables)
self.allocator.free_temp(&left_reg);
self.allocator.free_temp(&right_reg);
Ok((result_reg, code))
}
Expression::Call { name, args } => {
// first evaluate all the args we're going to need
let mut arg_regs = Vec::new();
for arg in args.iter().rev() {
let (arg_reg, arg_code) = self.generate_expression(arg, true)?;
code.extend(arg_code);
arg_regs.push(arg_reg);
}
// Save caller-saved registers and track which ones we saved
// old method, inefficient.
// let saved_regs = self.allocator.get_caller_saved_registers();
// for reg in &saved_regs {
// code.push(format!("\tpush {}", reg));
// }
// Save caller-saved registers and track which ones we saved
let saved_regs = self.allocator.get_caller_saved_registers();
for reg in &saved_regs {
// spill variables to stack
code.extend(self.allocator.spill_register(reg).unwrap());
}
// Evaluate and push arguments in reverse order
for (i, arg_reg) in arg_regs.iter().enumerate() {
code.push(format!(
"\tpush {} // push arg {}",
arg_reg,
args.len() - 1 - i
));
}
// if GLOBAL_METHODS.contains_key(name.name.as_str()) {
// code.push(format!("\tcall {}",
// GLOBAL_METHODS[name.name.as_str()])); } else
if self.symbols.contains(&name.name) {
// Call local function
code.push(format!("\tcall {}", name));
} else if let Some(ns) = name.namespace.clone()
&& self.imports.contains_key(&ns)
{
code.push(format!("\tcall {}", name));
} else {
return Err(CompilerError::Undefined(name.clone()));
}
let result_reg: String;
if use_result {
let (temp_result_reg, result_alloc) = self.allocator.alloc_temp()?;
result_reg = temp_result_reg;
code.extend(result_alloc);
code.push(format!("\tpop {}", result_reg));
// Clean up arguments
if args.len() > 1 {
for _ in 0..(args.len() - 1) {
code.push("\tpop zero".to_string());
}
}
} else {
result_reg = "zero".to_string();
// Clean up arguments
if args.len() > 0 {
for _ in 0..(args.len()) {
code.push("\tpop zero".to_string());
}
}
}
// Restore caller-saved registers in reverse order (LIFO)
// for reg in saved_regs.iter().rev() {
// code.push(format!("\tpop {}", reg));
// }
// Free argument registers
for reg in arg_regs {
self.allocator.free_temp(&reg);
}
Ok((result_reg, code))
}
Expression::Unary { op, operand } => {
let (operand_reg, operand_code) =
self.generate_expression(operand, true)?;
code.extend(operand_code);
let (result_reg, result_alloc) = self.allocator.alloc_temp()?;
code.extend(result_alloc);
match op {
UnaryOperator::Minus => {
// Negate: result = 0 - operand
code.push(format!("\tsub zero, {}, {}", operand_reg, result_reg));
}
UnaryOperator::Plus => {
// Just move
code.push(format!("\tmov {}, {}", operand_reg, result_reg));
}
UnaryOperator::Dereference => {
code.push(format!("\tldw {}, {}", operand_reg, result_reg));
}
UnaryOperator::Reference => {
code.extend(self.allocator.spill_register(&operand_reg)?);
code.push(format!(
"\tsubi bpr {} {}",
-(4 + self.allocator.get_stack_offset()),
result_reg
))
}
}
self.allocator.free_temp(&operand_reg);
Ok((result_reg, code))
}
Expression::Empty => Ok(("zero".to_string(), code)),
}
}
// Helper for generating unique labels
fn get_unique_label(&mut self) -> String {
// You'd implement a counter here
static COUNTER: AtomicU32 = AtomicU32::new(0);
let val = COUNTER.fetch_add(1, std::sync::atomic::Ordering::SeqCst);
(val + 1).to_string()
}
}
/// Build a single string from any number of arguments.
/// Each argument must implement `Display` or be convertible to a string.
#[macro_export]
macro_rules! dsa {
($($arg:expr),* $(,)?) => {{
// Start with an empty String well grow it as we go.
use std::fmt::Write;
let mut s = ::std::string::String::new();
$(
// `write!` is cheaper than `format!` for each element
// because it reuses the same buffer.
write!(s, "{}\n", $arg).expect("write to String failed");
)*
s
}};
}
// ──────────────────────── dsa! ────────────────────────
// A tiny helper that just turns its tokenstream into a string.
// The trailing comma is kept its part of the syntax you want.
#[macro_export]
macro_rules! cmd {
($($tokens:tt)*) => {{
// Well just stringify the tokens and return a String.
format!("{}", concat!(stringify!($tokens), "\n"))
}};
}
// ──────────────────────── block! ────────────────────────
// Usage:
//
// let asm = block![ "name"
// dsa![mov rg0, rg1],
// dsa![add rg1, rg1]
// ];
//
// `asm` is a `&'static str` containing:
//
// name:
// mov rg0, rg1
// add rg1, rg1
//
#[macro_export]
macro_rules! block {
// The first token must be a string literal thats the label.
($label:literal $(dsa![$($ins:tt)*]),* ) => {{
// Build a single string at compile time.
const CODE: &str = concat!(
$label, ":\n",
// Each `dsa!` call yields a string like `"mov rg0, rg1"`.
// We add a newline after each one to get the desired layout.
$(concat!("\t", stringify!($($ins)*), "\n")),*
);
CODE
}};
}
#[macro_export]
macro_rules! comment {
($text:expr) => {{ format!("// {}", $text) }};
}
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use crate::model::{CompilerError, Program};
mod codegen;
mod registers;
pub fn generate_code(ast: &Program) -> Result<String, CompilerError> {
let mut codegen = codegen::CodeGenerator::new(ast.clone());
codegen.generate()
}
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use std::collections::HashMap;
use crate::model::CompilerError;
/// Register allocator for DSA assembly generation
/// Manages general-purpose registers (rg0-rgf) and handles stack spilling
pub struct RegisterAllocator {
/// Available general-purpose registers
available_registers: Vec<String>,
/// Maps variable names to their current location (register or stack offset)
variable_locations: HashMap<String, Location>,
/// Maps registers to the variables they currently hold
register_contents: HashMap<String, String>,
/// Current stack offset for local variables (relative to bpr)
/// Starts at -4 (going downward from base pointer)
stack_offset: i32,
/// Track which registers are currently in use
in_use: HashMap<String, bool>,
}
#[derive(Debug, Clone)]
pub enum Location {
Register(String),
Stack(i32), // offset from bpr
}
impl RegisterAllocator {
pub fn new() -> Self {
// Initialize with available GP registers (rg0-rgf = 16 registers)
let registers = vec![
"rg0", "rg1", "rg2", "rg3", "rg4", "rg5", "rg6", "rg7", "rg8", "rg9", "rga",
"rgb", "rgc", "rgd", "rge", "rgf",
]
.into_iter()
.map(String::from)
.collect();
RegisterAllocator {
available_registers: registers,
variable_locations: HashMap::new(),
register_contents: HashMap::new(),
stack_offset: -4, // Start at -4 (first local below saved bpr)
in_use: HashMap::new(),
}
}
/// Allocate a temporary register for expression evaluation
/// Returns the register name and optionally assembly code to save it
pub fn alloc_temp(&mut self) -> Result<(String, Vec<String>), CompilerError> {
let mut code = Vec::new();
// Try to find an unused register
for reg in &self.available_registers {
if !self.in_use.get(reg).unwrap_or(&false) {
self.in_use.insert(reg.clone(), true);
return Ok((reg.clone(), code));
}
}
// All registers in use - need to spill one
// Choose the first register with a variable we can spill
// Find a register to spill
let reg_to_spill = self
.available_registers
.iter()
.find(|reg| self.register_contents.contains_key(*reg))
.cloned();
if let Some(reg) = reg_to_spill {
// Spill this variable to stack
let spill_code = self.spill_register(&reg)?;
code.extend(spill_code);
self.in_use.insert(reg.clone(), true);
return Ok((reg, code));
}
Err(CompilerError::Generic(
"All registers are used up yet there are no variables to spill to the stack"
.to_string(),
))
}
/// Free a temporary register after use
/// NOTE: This will NOT free registers that contain variables!
/// Variables persist throughout their scope and must not be freed
pub fn free_temp(&mut self, reg: &str) {
// Check if this register contains a variable
if self.register_contents.contains_key(reg) {
// This register holds a variable - don't free it!
// Variables are only freed when they go out of scope via free_var()
return;
}
// This is a true temporary - safe to free
self.in_use.insert(reg.to_string(), false);
}
/// Allocate a register for a named variable
/// Returns the register and any necessary assembly code
pub fn alloc_var(
&mut self,
var_name: &str,
) -> Result<(String, Vec<String>), CompilerError> {
if let Some(location) = self.variable_locations.get(var_name).cloned() {
match location {
Location::Register(reg) => {
return Ok((reg.clone(), Vec::new()));
}
Location::Stack(offset) => {
// Variable was pushed, need to calculate actual position
let (reg, mut code) = self.alloc_temp()?;
// Load from bpr + offset (offset is negative)
code.push(format!("\tsubi bpr {} {}", -(offset + 4), reg));
code.push(format!(
"\tldw {}, {} // bpr{}: {}",
reg,
reg,
offset - 4,
var_name
));
// Update location to register
self.variable_locations
.insert(var_name.to_string(), Location::Register(reg.clone()));
self.register_contents
.insert(reg.clone(), var_name.to_string());
return Ok((reg, code));
}
}
}
// Variable doesn't have a location yet, allocate a new register
let (reg, code) = self.alloc_temp()?;
self.variable_locations
.insert(var_name.to_string(), Location::Register(reg.clone()));
self.register_contents
.insert(reg.clone(), var_name.to_string());
Ok((reg, code))
}
/// Get the current location of a variable
pub fn _get_var_location(&self, var_name: &str) -> Option<&Location> {
self.variable_locations.get(var_name)
}
/// Load a variable into a register (allocating if necessary)
/// Returns the register and assembly code to load it
pub fn load_var(
&mut self,
var_name: &str,
) -> Result<(String, Vec<String>), CompilerError> {
self.alloc_var(var_name)
}
/// Store a value from a register into a variable
/// Updates tracking and returns any necessary assembly code
pub fn store_var(&mut self, var_name: &str, source_reg: &str) -> Vec<String> {
let mut code = Vec::new();
// Check if variable already has a location
if let Some(location) = self.variable_locations.get(var_name) {
match location {
Location::Register(dest_reg) => {
if dest_reg != source_reg {
code.push(format!(
"\tmov {}, {} // var {}",
source_reg, dest_reg, var_name
));
}
}
Location::Stack(offset) => {
code.push(format!(
"\tstw {}, bpr, {} // var {}",
source_reg, offset, var_name
));
}
}
} else {
// Variable doesn't exist yet, we can just use the same reg.
// self.variable_locations.insert(
// var_name.to_string(),
// Location::Register(source_reg.to_string()),
// );
// self.register_contents
// .insert(source_reg.to_string(), var_name.to_string());
// self.in_use.insert(source_reg.to_string(), true);
let source_reg = source_reg.to_string();
// if we can avoid a move, absolutely do that.
if self.available_registers.contains(&source_reg) {
self.variable_locations
.insert(var_name.to_string(), Location::Register(source_reg.clone()));
self.register_contents
.insert(source_reg.clone(), var_name.to_string());
self.in_use.insert(source_reg, true);
} else if let Some(free_reg) = self.find_free_register() {
code.push(format!("\tmov {}, {}", source_reg, free_reg));
self.variable_locations
.insert(var_name.to_string(), Location::Register(free_reg.clone()));
self.register_contents
.insert(free_reg.clone(), var_name.to_string());
self.in_use.insert(free_reg, true);
} else {
// No free registers - allocate on stack
// code.push(format!("\tstw {}, bpr, {}", source_reg, self.stack_offset));
// self.variable_locations
// .insert(var_name.to_string(), Location::Stack(self.stack_offset));
// self.stack_offset -= 4; // Move to next stack slot
//
todo!(
"we should spill other registers and keep this variable on the stack as it's more recent!"
);
}
}
code
}
/// Spill a register to the stack
/// Returns assembly code to perform the spill
pub fn spill_register(&mut self, reg: &str) -> Result<Vec<String>, CompilerError> {
let mut code = Vec::new();
if let Some(var_name) = self.register_contents.get(reg).cloned() {
// PUSH register to stack (spr decrements automatically)
code.push(format!(
"\tpush {} // bpr{}: {}",
reg, self.stack_offset, var_name
));
// Track that we pushed one word
self.stack_offset -= 4;
// Update variable location - it's now at current spr
// Note: We track offset from bpr for consistency
self.variable_locations
.insert(var_name.clone(), Location::Stack(self.stack_offset));
// Remove from register tracking
self.register_contents.remove(reg);
}
Ok(code)
}
/// Find a free register (not currently in use)
fn find_free_register(&self) -> Option<String> {
for reg in &self.available_registers {
if !self.in_use.get(reg).unwrap_or(&false) {
return Some(reg.clone());
}
}
None
}
/// Spill all registers to stack (useful before function calls)
pub fn _spill_all(&mut self) -> Vec<String> {
let mut code = Vec::new();
let regs_to_spill: Vec<String> = self.register_contents.keys().cloned().collect();
for reg in regs_to_spill {
if let Ok(spill_code) = self.spill_register(&reg) {
code.extend(spill_code);
}
}
code
}
/// Get the total stack offset
pub fn get_stack_offset(&self) -> i32 {
self.stack_offset
}
/// Get the total stack space needed for local variables
pub fn _get_stack_size(&self) -> i32 {
-self.stack_offset // Convert negative offset to positive size
}
/// Reset allocator for a new function
pub fn reset(&mut self) {
self.variable_locations.clear();
self.register_contents.clear();
self.stack_offset = -4;
self.in_use.clear();
}
/// Mark a variable as dead (no longer needed)
/// Frees its register if it's in one
pub fn _free_var(&mut self, var_name: &str) {
if let Some(Location::Register(reg)) = self.variable_locations.get(var_name) {
let reg = reg.clone();
self.register_contents.remove(&reg);
self.in_use.insert(reg, false);
}
self.variable_locations.remove(var_name);
}
/// Get list of registers that contain variables and are in use
/// These need to be saved before function calls
pub fn get_caller_saved_registers(&self) -> Vec<String> {
self.register_contents
.iter()
.filter(|(reg, _)| *self.in_use.get(*reg).unwrap_or(&false))
.map(|(reg, _)| reg.clone())
.collect()
}
/// Save caller-saved registers before a function call
/// Returns assembly code to save them
pub fn _save_caller_saved(&mut self) -> Vec<String> {
let mut code = Vec::new();
// For simplicity, save all currently used registers
// In a more sophisticated compiler, you'd only save registers that are live
for (reg, _) in self.register_contents.clone() {
if *self.in_use.get(&reg).unwrap_or(&false) {
code.push(format!("\tpush {}", reg));
}
}
code
}
/// Restore caller-saved registers after a function call
/// Returns assembly code to restore them
pub fn _restore_caller_saved(&mut self, saved_regs: &[String]) -> Vec<String> {
let mut code = Vec::new();
// Restore in reverse order (LIFO)
for reg in saved_regs.iter().rev() {
code.push(format!("\tpop {}", reg));
}
code
}
}
+13
View File
@@ -0,0 +1,13 @@
use crate::model::{CompilerError, Program};
mod dsa;
pub fn compiler_backend(ext: &str, ast: &Program) -> Result<String, CompilerError> {
match ext {
"dsa" => Ok(dsa::generate_code(ast)?),
_ => Err(CompilerError::Generic(format!(
"File type {} not supported",
ext
))),
}
}