540 lines
20 KiB
Rust
540 lines
20 KiB
Rust
use std::{collections::HashMap, fmt::Write};
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use crate::{
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parser::{Expr, Stmt},
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tokenizer::{TokenType, ZernError, error},
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};
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pub struct Var {
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// pub var_type: String,
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pub stack_offset: usize,
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}
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pub struct Env {
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scopes: Vec<HashMap<String, Var>>,
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next_offset: usize,
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loop_begin_label: String,
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loop_end_label: String,
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}
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impl Env {
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pub fn new() -> Env {
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Env {
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scopes: vec![HashMap::new()],
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next_offset: 8,
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loop_begin_label: String::new(),
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loop_end_label: String::new(),
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}
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}
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pub fn push_scope(&mut self) {
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self.scopes.push(HashMap::new());
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}
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pub fn pop_scope(&mut self) {
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self.scopes.pop();
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}
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pub fn define_var(&mut self, name: String, _var_type: String) -> usize {
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let offset = self.next_offset;
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self.next_offset += 8;
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self.scopes.last_mut().unwrap().insert(
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name,
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Var {
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stack_offset: offset,
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},
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);
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offset
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}
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pub fn get_var(&self, name: &str) -> Option<&Var> {
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for scope in self.scopes.iter().rev() {
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if let Some(var) = scope.get(name) {
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return Some(var);
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}
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}
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None
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}
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}
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macro_rules! emit {
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($($arg:tt)*) => {
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let _ = writeln!($($arg)*);
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};
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}
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static REGISTERS: [&str; 6] = ["rdi", "rsi", "rdx", "rcx", "r8", "r9"];
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pub struct CodegenX86_64 {
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output: String,
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data_section: String,
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label_counter: usize,
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data_counter: usize,
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}
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impl CodegenX86_64 {
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pub fn new() -> CodegenX86_64 {
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CodegenX86_64 {
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output: String::new(),
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data_section: String::new(),
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label_counter: 0,
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data_counter: 1,
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}
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}
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fn label(&mut self) -> String {
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self.label_counter += 1;
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format!(".L{}", self.label_counter)
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}
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pub fn get_output(&self) -> String {
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format!(
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"section .data
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{}{}",
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self.data_section, self.output
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)
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}
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pub fn emit_prologue(&mut self) -> Result<(), ZernError> {
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emit!(
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&mut self.output,
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"section .note.GNU-stack
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db 0
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section .text
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"
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);
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// take that rustfmt
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for name in "malloc,memset,realloc,free,puts,putchar,printf,snprintf,strtol,strlen,strcmp,strcat,strcpy,strncpy,fopen,fseek,ftell,fread,fwrite,fclose,rewind,system,opendir,readdir,closedir,exit,gettimeofday,connect,socket,send,write,read,close,bind,listen,accept,getchar,gethostbyname,dlopen,dlsym".split(",")
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{
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emit!(&mut self.output, "extern {}", name);
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emit!(&mut self.output, "c.{} equ {}", name, name);
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}
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emit!(
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&mut self.output,
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"
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section .text._builtin_read8
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_builtin_read8:
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xor rax, rax
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mov al, byte [rdi]
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ret
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section .text._builtin_read64
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_builtin_read64:
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mov rax, qword [rdi]
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ret
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section .text._builtin_set8
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_builtin_set8:
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mov [rdi], sil
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ret
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section .text._builtin_set64
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_builtin_set64:
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mov [rdi], rsi
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ret
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"
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);
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Ok(())
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}
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pub fn compile_stmt(&mut self, env: &mut Env, stmt: Stmt) -> Result<(), ZernError> {
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match stmt {
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Stmt::Expression(expr) => self.compile_expr(env, expr)?,
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Stmt::Let {
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name,
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var_type,
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initializer,
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} => {
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// TODO: move to analyzer
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if env.get_var(&name.lexeme).is_some() {
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return error!(
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name.loc,
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format!("variable already defined: {}", &name.lexeme)
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);
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}
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self.compile_expr(env, initializer)?;
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let offset = env.define_var(name.lexeme.clone(), var_type.lexeme);
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emit!(&mut self.output, " mov QWORD [rbp-{}], rax", offset);
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}
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Stmt::Block(statements) => {
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env.push_scope();
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for stmt in statements {
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self.compile_stmt(env, stmt)?;
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}
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env.pop_scope();
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}
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Stmt::If {
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condition,
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then_branch,
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else_branch,
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} => {
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let else_label = self.label();
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let end_label = self.label();
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self.compile_expr(env, condition)?;
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emit!(&mut self.output, " test rax, rax");
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emit!(&mut self.output, " je {}", else_label);
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self.compile_stmt(env, *then_branch.clone())?;
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emit!(&mut self.output, " jmp {}", end_label);
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emit!(&mut self.output, "{}:", else_label);
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self.compile_stmt(env, *else_branch.clone())?;
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emit!(&mut self.output, "{}:", end_label);
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}
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Stmt::While { condition, body } => {
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let old_loop_begin_label = env.loop_begin_label.clone();
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let old_loop_end_label = env.loop_end_label.clone();
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env.loop_begin_label = self.label();
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env.loop_end_label = self.label();
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emit!(&mut self.output, "{}:", env.loop_begin_label);
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self.compile_expr(env, condition)?;
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emit!(&mut self.output, " test rax, rax");
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emit!(&mut self.output, " je {}", env.loop_end_label);
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self.compile_stmt(env, *body.clone())?;
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emit!(&mut self.output, " jmp {}", env.loop_begin_label);
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emit!(&mut self.output, "{}:", env.loop_end_label);
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env.loop_begin_label = old_loop_begin_label;
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env.loop_end_label = old_loop_end_label;
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}
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Stmt::Function {
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name,
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params,
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return_type: _,
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body,
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} => {
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if name.lexeme == "main" {
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emit!(&mut self.output, "global {}", name.lexeme);
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}
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emit!(&mut self.output, "section .text.{}", name.lexeme);
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emit!(&mut self.output, "{}:", name.lexeme);
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emit!(&mut self.output, " push rbp");
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emit!(&mut self.output, " mov rbp, rsp");
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emit!(&mut self.output, " sub rsp, 256"); // TODO
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for (i, param) in params.iter().enumerate() {
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let offset = env
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.define_var(param.var_name.lexeme.clone(), param.var_type.lexeme.clone());
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let reg = match REGISTERS.get(i) {
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Some(x) => x,
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None => return error!(&name.loc, "only up to 6 params allowed"),
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};
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emit!(&mut self.output, " mov QWORD [rbp-{}], {}", offset, reg);
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}
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self.compile_stmt(env, *body)?;
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// fallback to returning null
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emit!(&mut self.output, " mov rax, 0");
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emit!(&mut self.output, " mov rsp, rbp");
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emit!(&mut self.output, " pop rbp");
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emit!(&mut self.output, " ret");
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}
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Stmt::Return(expr) => {
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self.compile_expr(env, expr)?;
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emit!(&mut self.output, " mov rsp, rbp");
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emit!(&mut self.output, " pop rbp");
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emit!(&mut self.output, " ret");
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}
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Stmt::For {
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var,
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start,
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end,
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body,
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} => {
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let old_loop_begin_label = env.loop_begin_label.clone();
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let old_loop_end_label = env.loop_end_label.clone();
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env.loop_begin_label = self.label();
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env.loop_end_label = self.label();
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env.push_scope();
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let offset = env.define_var(var.lexeme, "I64".into());
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self.compile_expr(env, start)?;
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emit!(&mut self.output, " mov QWORD [rbp-{}], rax", offset);
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emit!(&mut self.output, "{}:", env.loop_begin_label);
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emit!(&mut self.output, " mov rax, QWORD [rbp-{}]", offset);
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emit!(&mut self.output, " push rax");
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self.compile_expr(env, end)?;
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emit!(&mut self.output, " pop rcx");
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emit!(&mut self.output, " cmp rcx, rax");
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emit!(&mut self.output, " jge {}", env.loop_end_label);
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self.compile_stmt(env, *body)?;
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emit!(&mut self.output, " mov rax, QWORD [rbp-{}]", offset);
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emit!(&mut self.output, " add rax, 1");
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emit!(&mut self.output, " mov QWORD [rbp-{}], rax", offset);
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emit!(&mut self.output, " jmp {}", env.loop_begin_label);
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emit!(&mut self.output, "{}:", env.loop_end_label);
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env.pop_scope();
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env.loop_begin_label = old_loop_begin_label;
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env.loop_end_label = old_loop_end_label;
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}
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Stmt::Break => {
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emit!(&mut self.output, " jmp {}", env.loop_end_label);
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}
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Stmt::Continue => {
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// TODO: skips incrementing when used in a for loop
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emit!(&mut self.output, " jmp {}", env.loop_begin_label);
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}
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Stmt::Extern(name) => {
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emit!(&mut self.output, " extern {}", name.lexeme);
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}
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}
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Ok(())
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}
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pub fn compile_expr(&mut self, env: &mut Env, expr: Expr) -> Result<(), ZernError> {
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match expr {
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Expr::Binary { left, op, right } => {
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self.compile_expr(env, *left)?;
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emit!(&mut self.output, " push rax");
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self.compile_expr(env, *right)?;
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emit!(&mut self.output, " mov rbx, rax");
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emit!(&mut self.output, " pop rax");
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match op.token_type {
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TokenType::Plus => {
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emit!(&mut self.output, " add rax, rbx");
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}
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TokenType::Minus => {
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emit!(&mut self.output, " sub rax, rbx");
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}
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TokenType::Star => {
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emit!(&mut self.output, " imul rax, rbx");
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}
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TokenType::Slash => {
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emit!(&mut self.output, " cqo");
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emit!(&mut self.output, " idiv rbx");
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}
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TokenType::Mod => {
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emit!(&mut self.output, " cqo");
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emit!(&mut self.output, " idiv rbx");
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emit!(&mut self.output, " mov rax, rdx");
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}
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TokenType::Xor => {
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emit!(&mut self.output, " xor rax, rbx");
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}
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TokenType::BitAnd => {
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emit!(&mut self.output, " and rax, rbx");
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}
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TokenType::BitOr => {
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emit!(&mut self.output, " or rax, rbx");
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}
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TokenType::DoubleEqual => {
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emit!(&mut self.output, " cmp rax, rbx");
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emit!(&mut self.output, " sete al");
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emit!(&mut self.output, " movzx rax, al");
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}
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TokenType::NotEqual => {
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emit!(&mut self.output, " cmp rax, rbx");
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emit!(&mut self.output, " setne al");
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emit!(&mut self.output, " movzx rax, al");
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}
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TokenType::Greater => {
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emit!(&mut self.output, " cmp rax, rbx");
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emit!(&mut self.output, " setg al");
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emit!(&mut self.output, " movzx rax, al");
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}
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TokenType::GreaterEqual => {
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emit!(&mut self.output, " cmp rax, rbx");
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emit!(&mut self.output, " setge al");
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emit!(&mut self.output, " movzx rax, al");
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}
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TokenType::Less => {
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emit!(&mut self.output, " cmp rax, rbx");
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emit!(&mut self.output, " setl al");
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emit!(&mut self.output, " movzx rax, al");
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}
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TokenType::LessEqual => {
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emit!(&mut self.output, " cmp rax, rbx");
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emit!(&mut self.output, " setle al");
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emit!(&mut self.output, " movzx rax, al");
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}
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TokenType::ShiftLeft => {
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emit!(&mut self.output, " mov rcx, rbx");
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emit!(&mut self.output, " sal rax, cl");
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}
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TokenType::ShiftRight => {
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emit!(&mut self.output, " mov rcx, rbx");
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emit!(&mut self.output, " sar rax, cl");
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}
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_ => unreachable!(),
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}
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}
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Expr::Grouping(expr) => self.compile_expr(env, *expr)?,
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Expr::Literal(token) => match token.token_type {
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TokenType::Number => {
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emit!(&mut self.output, " mov rax, {}", token.lexeme);
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}
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TokenType::Char => {
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emit!(
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&mut self.output,
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" mov rax, {}",
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token.lexeme.chars().nth(1).unwrap() as u8
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);
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}
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TokenType::String => {
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// TODO: actual string parsing in the tokenizer
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let value = &token.lexeme[1..token.lexeme.len() - 1]
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.replace("\\n", "\n")
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.replace("\\r", "\r")
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.replace("\\t", "\t")
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.replace("\\033", "\x1b")
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.replace("\\0", "\0");
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let label = format!("str_{:03}", self.data_counter);
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if value.is_empty() {
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emit!(&mut self.data_section, " {} db 0", label);
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} else {
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let charcodes = value
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.chars()
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.map(|x| (x as u8).to_string())
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.collect::<Vec<String>>()
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.join(",");
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emit!(&mut self.data_section, " {} db {},0", label, charcodes,);
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}
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emit!(&mut self.output, " mov rax, {}", label);
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self.data_counter += 1;
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}
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TokenType::True => {
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emit!(&mut self.output, " mov rax, 1");
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}
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TokenType::False => {
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emit!(&mut self.output, " mov rax, 0");
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}
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_ => unreachable!(),
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},
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Expr::Unary { op, right } => {
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self.compile_expr(env, *right)?;
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match op.token_type {
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TokenType::Minus => {
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emit!(&mut self.output, " neg rax");
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}
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TokenType::Bang => {
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emit!(&mut self.output, " test rax, rax");
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emit!(&mut self.output, " sete al");
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emit!(&mut self.output, " movzx rax, al");
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}
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_ => unreachable!(),
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}
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}
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Expr::Variable(name) => {
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// TODO: move to analyzer
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let var = match env.get_var(&name.lexeme) {
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Some(x) => x,
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None => {
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return error!(name.loc, format!("undefined variable: {}", &name.lexeme));
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}
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};
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emit!(
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&mut self.output,
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" mov rax, QWORD [rbp-{}]",
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var.stack_offset,
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);
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}
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Expr::Assign { name, value } => {
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self.compile_expr(env, *value)?;
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// TODO: move to analyzer
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let var = match env.get_var(&name.lexeme) {
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Some(x) => x,
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None => {
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return error!(name.loc, format!("undefined variable: {}", &name.lexeme));
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}
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};
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emit!(
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&mut self.output,
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" mov QWORD [rbp-{}], rax",
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var.stack_offset,
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);
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}
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Expr::Call {
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callee,
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paren,
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args,
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} => {
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let callee = match *callee {
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Expr::Variable(name) => name.lexeme,
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_ => return error!(&paren.loc, "tried to call a non-constant expression"),
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};
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for arg in &args {
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self.compile_expr(env, arg.clone())?;
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emit!(&mut self.output, " push rax");
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}
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let arg_count = args.len();
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if arg_count <= 6 {
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for i in (0..arg_count).rev() {
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emit!(&mut self.output, " pop {}", REGISTERS[i]);
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}
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} else {
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for (i, reg) in REGISTERS.iter().enumerate() {
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let offset = 8 * (arg_count - 1 - i);
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emit!(
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&mut self.output,
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" mov {}, QWORD [rsp + {}]",
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reg,
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offset
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);
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}
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let num_stack = arg_count - 6;
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for i in 0..num_stack {
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let arg_idx = arg_count - 1 - i;
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let offset = 8 * (arg_count - 1 - arg_idx);
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emit!(&mut self.output, " mov rax, QWORD [rsp + {}]", offset);
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emit!(&mut self.output, " push rax");
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}
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}
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match env.get_var(&callee) {
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Some(var) => {
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emit!(
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&mut self.output,
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" mov rax, QWORD [rbp-{}]",
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var.stack_offset,
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);
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emit!(&mut self.output, " call rax");
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}
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None => {
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emit!(&mut self.output, " call {}", callee);
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}
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};
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if arg_count > 6 {
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|
let num_stack = arg_count - 6;
|
|
emit!(&mut self.output, " add rsp, {}", 8 * num_stack);
|
|
emit!(&mut self.output, " add rsp, {}", 8 * arg_count);
|
|
}
|
|
}
|
|
Expr::ArrayLiteral(exprs) => {
|
|
emit!(&mut self.output, " call array.new");
|
|
emit!(&mut self.output, " push rax");
|
|
|
|
for expr in exprs {
|
|
self.compile_expr(env, expr)?;
|
|
emit!(&mut self.output, " mov rsi, rax");
|
|
emit!(&mut self.output, " pop rdi");
|
|
emit!(&mut self.output, " push rdi");
|
|
emit!(&mut self.output, " call array.push");
|
|
}
|
|
emit!(&mut self.output, " pop rax");
|
|
}
|
|
Expr::Index { expr, index } => {
|
|
self.compile_expr(env, *expr)?;
|
|
emit!(&mut self.output, " mov rdi, rax");
|
|
self.compile_expr(env, *index)?;
|
|
emit!(&mut self.output, " add rdi, rax");
|
|
emit!(&mut self.output, " call _builtin_read8");
|
|
}
|
|
}
|
|
Ok(())
|
|
}
|
|
}
|