add (de-)serializable ObjectFile

linker: add add_procedure_front()

Cargo.toml

@@ -4,3 +4,5 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
+serde = { version = "1.0", features = ["derive"] }
+

src/assembler.rs

@@ -2,10 +2,11 @@ use {
     crate::{
         VM_Word, VM_Instruction,
         linker::LinkAddr
-    }
+    },
+    serde::{Serialize, Deserialize}
 };
 
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, Serialize, Deserialize)]
 pub enum AssemblyWord {
     Symbol( LinkAddr ),
     Lit( VM_Word )

src/linker.rs

@@ -1,12 +1,13 @@
 use {
     std::collections::HashMap,
-    crate::{VM_Word, assembler::AssemblyWord}
+    crate::{VM_Word, assembler::AssemblyWord},
+    serde::{Serialize, Deserialize}
 };
 
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, Serialize, Deserialize)]
 pub enum LinkAddr {
     Absolute(VM_Word),
-    Relative{
+    Relative {
         symbol: String,
         offset: VM_Word
     }
@@ -16,7 +17,7 @@ impl std::fmt::Display for LinkAddr {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
         match self {
             LinkAddr::Absolute(addr) =>
-                write!(f, "{:x}", addr),
+                write!(f, "{:#08x}", addr),
             LinkAddr::Relative{ symbol, offset } =>
                 if *offset == 0 {
                     write!(f, "{}", symbol)
@@ -27,14 +28,24 @@ impl std::fmt::Display for LinkAddr {
     }
 }
 
+#[derive(Serialize, Deserialize, Debug)]
+struct ObjAddr {
+    section_id: usize,
+    offset: i64
+}
+
+#[derive(Serialize, Deserialize, Debug)]
 pub struct Section {
-    addr: VM_Word,
-    data: Vec< AssemblyWord >
+    pub addr: VM_Word,
+    pub data: Vec< AssemblyWord >
 }
 
 pub struct Linker {
-    symbols: HashMap<String, Section>,
-    next_addr: VM_Word
+    pub sections: Vec<Section>,
+    pub symbols: HashMap<String, ObjAddr>,
+
+    // internal linker state
+    pub next_addr: VM_Word
 }
 
 #[derive(Clone, Debug)]
@@ -43,17 +54,38 @@ pub enum LinkError {
     RelativeAddrOutOfBounds( String, VM_Word )
 }
 
+#[derive(Serialize, Deserialize, Debug)]
+pub struct ObjectFile {
+    pub symbols: Vec< (String, VM_Word) >,
+    pub code: Vec< AssemblyWord >,
+}
+
 impl Linker {
     pub fn new() -> Self {
         Linker {
+            sections: Vec::new(),
             symbols: HashMap::new(),
             next_addr: 0
         }
     }
 
+    pub fn import(&mut self, source_name: &str, obj_file: ObjectFile) {
+        let section_id = self.add_procedure(
+            &source_name,
+            obj_file.code
+        );
+
+        for (symbol, offset) in obj_file.symbols {
+            self.symbols.insert(symbol, ObjAddr {
+                section_id,
+                offset
+            });
+        }
+    }
+
     pub fn link_partial(self) -> Result<Vec<AssemblyWord>, LinkError> {
         let mut bytecode = vec![ AssemblyWord::Lit(0); self.next_addr as usize ];
-        for (sym, Section{ mut addr, data }) in self.symbols.iter() {
+        for Section{ mut addr, data } in self.sections.iter() {
             for w in data {
                 bytecode[ addr as usize ] = self.resolve_link(w.clone())?;
                 addr += 1;
@@ -93,7 +125,10 @@ impl Linker {
 
     pub fn get_link_addr(&self, name: &String) -> Option<VM_Word> {
         match self.symbols.get(name) {
-            Some(section) => Some(section.addr),
+            Some(ObjAddr{ section_id, offset }) =>{
+                let section = self.sections.get(*section_id).unwrap();
+                Some(section.addr + offset)
+            },
             None => None
         }
     }
@@ -106,19 +141,31 @@ impl Linker {
         }
     }
 
+    pub fn get_symbol_range( &self, name: &str ) -> Option<(i64, usize)> {
+        if let Some(ObjAddr{ section_id, offset }) = self.symbols.get(name) {
+            if let Some(Section{ data, addr }) = self.sections.get(*section_id) {
+                Some((*addr as i64 + *offset as i64, data.len()))
+            } else {
+                None
+            }
+        } else {
+            None
+        }
+    }
+
     pub fn resolve_link_addr(&self, addr: LinkAddr) -> Result<LinkAddr, LinkError> {
         match addr {
             LinkAddr::Absolute(w) => Ok(LinkAddr::Absolute(w)),
             LinkAddr::Relative{ symbol, offset } => {
-                match self.symbols.get(&symbol){
-                    Some(Section{ addr, data }) => {
-                        if offset < data.len() as i64 && offset >= 0 {
-                            Ok(LinkAddr::Absolute( *addr as i64 + offset as i64 ))
-                        } else {
-                            Err(LinkError::RelativeAddrOutOfBounds(symbol, offset))
-                        }
-                    },
-                    None => Ok(LinkAddr::Relative{ symbol, offset })
+                if let Some((symbol_addr, len)) = self.get_symbol_range(&symbol) {
+                    if offset < len as i64 && offset >= 0 {
+                        Ok(LinkAddr::Absolute( symbol_addr + offset as i64 ))
+                    } else {
+                        eprintln!("symbol {} @ {}+{}", symbol, symbol_addr, len);
+                        Err(LinkError::RelativeAddrOutOfBounds(symbol, offset))
+                    }
+                } else {
+                    Ok(LinkAddr::Relative{ symbol, offset })
                 }
             }
         }
@@ -128,32 +175,75 @@ impl Linker {
         &mut self,
         symbol: &str,
         data: Vec<VM_Word>,
-    ) {
+    ) -> usize {
         let link_addr = self.next_addr;
         self.next_addr += data.len() as i64;
+
+        let section_id = self.sections.len();
+
+        self.sections.push(Section {
+            addr: link_addr,
+            data: data.into_iter().map(|w| AssemblyWord::Lit(w)).collect()
+        });
+
         self.symbols.insert(
             symbol.into(),
-            Section {
-                addr: link_addr,
-                data: data.into_iter().map(|w| AssemblyWord::Lit(w)).collect()
+            ObjAddr {
+                section_id,
+                offset: 0
             }
         );
+
+        section_id
+    }
+
+    pub fn add_procedure_front(
+        &mut self,
+        symbol: &str,
+        bytecode: Vec< AssemblyWord >
+    ) -> usize {
+        self.next_addr += bytecode.len() as i64;
+        for section in self.sections.iter_mut() {
+            section.addr += bytecode.len() as i64;
+        }
+
+        let section_id = self.sections.len();
+
+        self.sections.push(Section {
+            addr: 0,
+            data: bytecode
+        });
+
+        self.symbols.insert(symbol.into(), ObjAddr{
+            section_id,
+            offset: 0
+        });
+
+        section_id
     }
 
     pub fn add_procedure(
         &mut self,
         symbol: &str,
         bytecode: Vec< AssemblyWord >
-    ) {
+    ) -> usize {
         let link_addr = self.next_addr;
         self.next_addr += bytecode.len() as i64;
-        self.symbols.insert(
-            symbol.into(),
-            Section {
-                addr: link_addr,
-                data: bytecode
-            }
-        );
+
+        
+        let section_id = self.sections.len();
+
+        self.sections.push(Section {
+            addr: link_addr,
+            data: bytecode
+        });
+
+        self.symbols.insert(symbol.into(), ObjAddr{
+            section_id,
+            offset: 0
+        });
+
+        section_id
     }
 }