trying to refactor a bit:

- working on a string/bytes table
- no longer directly referencing ir outside of current function; the goal here
is to end up only generating ir for 1 function, then link together in assembling
step. this involves adding an GlobalRef() ast-node and ExternRef() ir instruction

src/ast.rs

@@ -77,6 +77,7 @@ pub enum Tag {
         assignment: Node,
     },
     DeclRef(Node),
+    GlobalRef(Node),
     CallExpr {
         /// Ident | Expr
         lhs: Node,

src/lib.rs

@@ -6,6 +6,7 @@ pub mod codegen;
 pub mod common;
 pub mod lexer;
 pub mod parser;
+pub mod string_table;
 pub mod symbol_table;
 pub mod tokens;
 pub mod triples;

src/parser.rs

@@ -793,15 +793,19 @@ impl Tree {
             Token::Ident => {
                 let ident = tokens.expect_token(Token::Ident)?;
 
-                let decl = match self.st.find_symbol(ident.lexeme()) {
-                    Some(rec) => rec.node(),
-                    None => self
+                let name = ident.lexeme();
+                if let Some(record) = self.st.find_ordered_symbol(name) {
+                    Ok(self.nodes.push_tag(Tag::DeclRef(record.node())))
+                } else if let Some(record) = self.st.find_orderless_symbol(name) {
+                    Ok(self.nodes.push_tag(Tag::GlobalRef(record.node())))
+                } else {
+                    let node = self
                         .st
-                        .insert_orderless_symbol(ident.lexeme(), self.nodes.reserve_node())
-                        .node(),
-                };
+                        .insert_orderless_symbol(name, self.nodes.reserve_node())
+                        .node();
 
-                Ok(self.nodes.push_tag(Tag::DeclRef(decl)))
+                    Ok(self.nodes.push_tag(Tag::GlobalRef(node)))
+                }
             }
             Token::IntegerBinConstant
             | Token::IntegerHexConstant
@@ -1328,6 +1332,23 @@ impl Tree {
                         ))
                 )
             }
+            Tag::GlobalRef(decl) => {
+                writeln_indented!(
+                    indent,
+                    writer,
+                    "%{} = global_ref(%{}, name: {})",
+                    node.get(),
+                    decl.get(),
+                    self.st
+                        .symbol_path(decl)
+                        .map(|p| p.mangle(self))
+                        .unwrap_or(format!(
+                            "SymbolTable entry not found?, %{}, %{}",
+                            node.get(),
+                            decl.get()
+                        ))
+                )
+            }
             _ => unreachable!(),
         }
     }

src/string_table.rs

@@ -0,0 +1,68 @@
+use std::{collections::BTreeMap, hash::Hasher};
+
+#[derive(Debug, Clone, Copy)]
+pub struct Index {
+    pub start: u32,
+    pub end: u32,
+}
+
+impl Index {
+    pub fn new(start: u32, end: u32) -> Self {
+        Self { start, end }
+    }
+}
+
+#[derive(Debug)]
+pub struct StringTable {
+    bytes: Vec<u8>,
+    indices: BTreeMap<u64, Index>,
+}
+
+impl core::ops::Index<Index> for StringTable {
+    type Output = [u8];
+
+    fn index(&self, idx: Index) -> &Self::Output {
+        &self.bytes[idx.start as usize..idx.end as usize]
+    }
+}
+
+impl StringTable {
+    pub fn new() -> Self {
+        Self {
+            bytes: Vec::new(),
+            indices: BTreeMap::new(),
+        }
+    }
+
+    pub fn get_str(&self, idx: Index) -> &str {
+        unsafe { core::str::from_utf8_unchecked(&self[idx]) }
+    }
+
+    pub fn get_bytes(&self, idx: Index) -> &[u8] {
+        &self[idx]
+    }
+
+    pub fn insert<B: AsRef<[u8]>>(&mut self, bytes: B) -> Index {
+        let bytes = bytes.as_ref();
+        let hash = {
+            let mut hasher = std::hash::DefaultHasher::new();
+            hasher.write(bytes);
+            hasher.finish()
+        };
+
+        if let Some(idx) = self.indices.get(&hash).cloned() {
+            idx
+        } else {
+            self.insert_inner(hash, bytes)
+        }
+    }
+
+    fn insert_inner(&mut self, hash: u64, bytes: &[u8]) -> Index {
+        let start = self.bytes.len();
+        self.bytes.extend(bytes);
+        let end = self.bytes.len();
+        let index = Index::new(start as u32, end as u32);
+        self.indices.insert(hash, index);
+        index
+    }
+}

src/symbol_table.rs

@@ -3,7 +3,10 @@ use std::{
     ptr::NonNull,
 };
 
-use crate::ast::Node as AstNode;
+use crate::{
+    ast::{Node as AstNode, Tag},
+    parser::Tree,
+};
 
 #[derive(Debug)]
 pub struct SymbolRecord {
@@ -21,6 +24,33 @@ impl SymbolRecord {
     }
 }
 
+#[allow(unused)]
+pub struct SymbolPath(Vec<Option<AstNode>>, String);
+
+impl SymbolPath {
+    pub fn mangle(&self, tree: &Tree) -> String {
+        use core::fmt::Write;
+        let mut buf = String::new();
+
+        for node in self.0.iter().skip(1).rev() {
+            match tree.nodes.get_node(node.unwrap()) {
+                Tag::VarDecl { name, .. } => {
+                    _ = write!(&mut buf, "V{}::", tree.nodes.get_ident_str(*name).unwrap());
+                }
+                Tag::GlobalDecl { name, .. } => {
+                    _ = write!(&mut buf, "G{}::", tree.nodes.get_ident_str(*name).unwrap());
+                }
+                Tag::FunctionProto { name, .. } => {
+                    _ = write!(&mut buf, "F{}::", tree.nodes.get_ident_str(*name).unwrap());
+                }
+                _ => {}
+            }
+        }
+        _ = write!(&mut buf, "{}", self.1);
+        buf
+    }
+}
+
 pub enum SymbolKind {
     Var, // or Let
     Orderless,
@@ -31,33 +61,38 @@ struct InnerSymbolTable {
     ordered_identifiers: Vec<SymbolRecord>,
     orderless_identifiers: HashMap<String, SymbolRecord>,
     children: BTreeMap<AstNode, NonNull<InnerSymbolTable>>,
+    scope: Option<AstNode>,
     parent: Option<NonNull<InnerSymbolTable>>,
 }
 impl InnerSymbolTable {
     fn new() -> NonNull<InnerSymbolTable> {
         Self::new_with(Self::new_inner)
     }
+
     fn new_with<G>(gen: G) -> NonNull<InnerSymbolTable>
     where
         G: FnOnce() -> Self,
     {
         NonNull::new(Box::leak(Box::new(gen())) as *mut _).unwrap()
     }
+
     fn new_inner() -> InnerSymbolTable {
         Self {
             parent: None,
             ordered_identifiers: Vec::new(),
             orderless_identifiers: HashMap::new(),
             children: BTreeMap::new(),
+            scope: None,
         }
     }
 
-    fn make_child(&self) -> NonNull<InnerSymbolTable> {
+    fn make_child(&self, scope: AstNode) -> NonNull<InnerSymbolTable> {
         Self::new_with(|| Self {
             parent: NonNull::new(self.as_ptr()),
             ordered_identifiers: Vec::new(),
             orderless_identifiers: HashMap::new(),
             children: BTreeMap::new(),
+            scope: Some(scope),
         })
     }
 
@@ -124,7 +159,7 @@ impl InnerSymbolTable {
         F: FnOnce() -> (AstNode, SymbolKind),
     {
         let this = self as *mut Self;
-        if let Some(record) = unsafe { &*this }.find_symbol(name) {
+        if let Some(record) = unsafe { &*this }.find_any_symbol(name) {
             record
         } else {
             let (node, kind) = cb();
@@ -145,12 +180,19 @@ impl InnerSymbolTable {
             .or_else(|| self.parent_ref().and_then(|p| p.find_symbol_by_decl(decl)))
     }
 
-    fn find_symbol(&self, name: &str) -> Option<&SymbolRecord> {
+    fn find_any_symbol(&self, name: &str) -> Option<&SymbolRecord> {
         self.ordered_identifiers
             .iter()
             .find(|r| r.name.as_str() == name)
             .or_else(|| self.orderless_identifiers.get(name))
-            .or_else(|| self.parent_ref().and_then(|p| p.find_symbol(name)))
+            .or_else(|| self.parent_ref().and_then(|p| p.find_any_symbol(name)))
+    }
+
+    fn find_ordered_symbol(&self, name: &str) -> Option<&SymbolRecord> {
+        self.ordered_identifiers
+            .iter()
+            .find(|r| r.name.as_str() == name)
+            .or_else(|| self.parent_ref().and_then(|p| p.find_ordered_symbol(name)))
     }
 
     fn find_orderless_symbol(&self, name: &str) -> Option<&SymbolRecord> {
@@ -229,7 +271,7 @@ impl SymbolTableWrapper {
         let child = if let Some(child) = self.current().children.get(&scope) {
             *child
         } else {
-            let child = self.current().make_child();
+            let child = self.current().make_child(scope);
             self.current_mut().children.insert(scope, child);
             child
         };
@@ -271,14 +313,50 @@ impl SymbolTableWrapper {
         self.current().find_symbol_by_decl(decl)
     }
 
-    pub fn find_symbol(&self, name: &str) -> Option<&SymbolRecord> {
-        self.current().find_symbol(name)
+    pub fn find_any_symbol(&self, name: &str) -> Option<&SymbolRecord> {
+        self.current().find_any_symbol(name)
+    }
+
+    pub fn find_ordered_symbol(&self, name: &str) -> Option<&SymbolRecord> {
+        self.current().find_ordered_symbol(name)
     }
 
     pub fn find_orderless_symbol(&self, name: &str) -> Option<&SymbolRecord> {
         self.current().find_orderless_symbol(name)
     }
 
+    pub fn symbol_path(&self, decl: AstNode) -> Option<SymbolPath> {
+        let mut table = self.current();
+        loop {
+            if let Some(record) = table
+                .ordered_identifiers
+                .iter()
+                .find(|r| r.node() == decl)
+                .or_else(|| {
+                    table
+                        .orderless_identifiers
+                        .iter()
+                        .find(|(_, v)| v.decl == decl)
+                        .map(|(_, v)| v)
+                })
+            {
+                let mut path = Vec::new();
+                while let Some(parent) = table.parent_ref() {
+                    path.push(parent.scope);
+                }
+
+                return Some(SymbolPath(path, record.name.clone()));
+            };
+
+            let Some(parent) = table.parent_ref() else {
+                break;
+            };
+            table = parent;
+        }
+
+        None
+    }
+
     pub fn extend_orderless<I>(&mut self, iter: I)
     where
         I: IntoIterator<Item = (String, SymbolRecord)>,

src/triples.rs

@@ -19,6 +19,7 @@ enum Inst {
     Label(String),
     Constant(Value),
     UnresolvedRef,
+    ExternRef(AstNode),
     Ref(Node),
     Parameter { size: u32, align: u32 },
     Add { lhs: Node, rhs: Node },
@@ -135,7 +136,7 @@ impl<'tree, 'ir> IRBuilder<'tree, 'ir> {
                 }
                 !0
             }
-            Tag::Parameter { name, ty } => {
+            Tag::Parameter { ty, .. } => {
                 let ty = self.tree.type_of_node(*ty);
                 let param = self.ir.push(Inst::Parameter {
                     size: ty.size_of(),
@@ -314,6 +315,7 @@ impl<'tree, 'ir> IRBuilder<'tree, 'ir> {
                     unresolved
                 }
             },
+            Tag::GlobalRef(decl) => self.ir.push(Inst::ExternRef(*decl)),
             Tag::Ref { lhs } => {
                 let lhs = self.visit(*lhs);
                 self.ir.push(Inst::AddressOf(lhs))
@@ -435,6 +437,15 @@ impl IR {
             Inst::Store { dest, source } => {
                 writeln_indented!(indent, w, "%{} = store ptr %{dest} from %{source}", node)?;
             }
+            Inst::ExternRef(ast_node) => {
+                writeln_indented!(
+                    indent,
+                    w,
+                    "%{} = extern reference ast-node %{}",
+                    node,
+                    ast_node.get()
+                )?;
+            }
         }
         Ok(())
     }