feat: add ir level symbol.

tigerc/src/frame.rs

@@ -1,6 +1,7 @@
 use indexmap::IndexMap;
 
-use crate::ident_pool::{self, Symbol};
+use crate::ident_pool::Symbol;
+use crate::ir;
 
 pub enum Access {
     // offset to frame pointer
@@ -18,43 +19,37 @@ pub struct Variable {
 }
 
 pub trait Frame {
-    fn new(name: Symbol, parameters: IndexMap<Symbol, Variable>) -> Self;
+    fn new(name: Symbol, parameters: IndexMap<ir::LowerIdent, Variable>) -> Self;
     fn name(&self) -> Symbol;
-    fn allocate_local(&mut self, symbol: Symbol, var: Variable);
+    fn allocate_local(&mut self, symbol: ir::LowerIdent, var: Variable);
 }
 
 // frame of a function
 struct FrameAmd64 {
     // function name
     name: Symbol,
     // parameters
-    parameters: IndexMap<Symbol, Variable>,
+    parameters: IndexMap<ir::LowerIdent, Variable>,
     // local variables
-    locals: IndexMap<Symbol, Variable>,
-    // counting same name variable
-    id: usize,
+    locals: IndexMap<ir::LowerIdent, Variable>,
 }
 
 impl Frame for FrameAmd64 {
-    fn new(name: Symbol, parameters: IndexMap<Symbol, Variable>) -> Self {
+    fn new(name: Symbol, parameters: IndexMap<ir::LowerIdent, Variable>) -> Self {
         FrameAmd64 {
             name,
             parameters,
             locals: IndexMap::new(),
-            id: 0,
         }
     }
 
     fn name(&self) -> Symbol {
         self.name
     }
 
-    fn allocate_local(&mut self, symbol: Symbol, var: Variable) {
+    fn allocate_local(&mut self, symbol: ir::LowerIdent, var: Variable) {
         if self.locals.contains_key(&symbol) {
-            self.locals.insert(
-                ident_pool::create_symbol(&format!("{}:{}", symbol, self.id)),
-                var,
-            );
+            self.locals.insert(symbol, var);
         } else {
             self.locals.insert(symbol, var);
         }

tigerc/src/ir.rs

@@ -0,0 +1,38 @@
+use std::hash::Hash;
+
+use crate::ident_pool::Symbol;
+
+// Identify different symbol with same name
+// We will flatten symbol scope when translate it to IR which close to machine code
+#[derive(Eq, Debug)]
+pub struct LowerIdent {
+    // this is used just for debug
+    pub symbol: Symbol,
+    pub number: usize,
+}
+
+impl LowerIdent {
+    pub fn new(symbol: Symbol) -> LowerIdent {
+        // It's safe in single thread
+        static mut COUNTER: usize = 0;
+        LowerIdent {
+            symbol,
+            number: unsafe {
+                COUNTER += 1;
+                COUNTER
+            },
+        }
+    }
+}
+
+impl PartialEq for LowerIdent {
+    fn eq(&self, other: &Self) -> bool {
+        self.number == other.number
+    }
+}
+
+impl Hash for LowerIdent {
+    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+        self.number.hash(state);
+    }
+}

tigerc/src/lib.rs

@@ -3,6 +3,7 @@ pub mod cursor;
 pub mod escape;
 pub mod frame;
 pub mod ident_pool;
+pub mod ir;
 pub mod parser;
 pub mod symbol_table;
 pub mod tokenizer;