Static allocations

forge_core/src/ast.rs

@@ -173,6 +173,7 @@ pub enum Expr {
     Address(Lvalue),
     Call(Call),
     New(BoxExpr),
+    Static(BoxExpr),
     Subscript(BoxExpr, BoxExpr),
     Infix(BoxExpr, Operator, BoxExpr),
     String(String),

forge_core/src/compiler/ast_nodes/const.rs

@@ -44,7 +44,7 @@ pub fn eval_const(expr: Expr, scope: &Scope) -> Result<i32, CompileError> {
         // (currently) parsed as a special case of const. The only things that will hit this are
         // const expressions that include strings, like '"foo"[2]' or something. Those can't be
         // (generally) calculated at compile time, so, they're an error.
-        Expr::Address(_) | Expr::Deref(_) | Expr::String(_) => Err(CompileError(
+        Expr::Address(_) | Expr::Deref(_) | Expr::String(_) | Expr::Static(_) => Err(CompileError(
             0,
             0,
             String::from("Addresses are not known at compile time"),

forge_core/src/compiler/ast_nodes/expr.rs

@@ -91,6 +91,9 @@ impl Compilable for Expr {
                 compile_alloc(&mut sig);
                 Ok(())
             },
+            Expr::Static(size_expr) => {
+                compile_static(size_expr, state, sig)
+            }
             Expr::Subscript(array, index) => {
                 array.0.process(state, Some(sig), loc)?;
                 index.0.process(state, Some(sig), loc)?;
@@ -174,6 +177,13 @@ fn compile_alloc(sig: &mut CompiledFn) {
     sig.emit("pushr");
 }
 
+fn compile_static(expr: BoxExpr, state: &mut State, sig: &mut CompiledFn) -> Result<(), CompileError> {
+    let size = eval_const(*expr.0, &state.global_scope)? as usize;
+    let label = state.add_buffer(size * 3);
+    sig.emit_arg("push", label);
+    Ok(())
+}
+
 #[cfg(test)]
 mod test {
     use crate::compiler::test_utils::*;
@@ -282,4 +292,16 @@ mod test {
             ].join("\n")
         )
     }
+
+    #[test]
+    fn test_static() {
+        assert_eq!(
+            test_body(state_for("fn test() { var x = static(1); }")),
+            vec![
+                "push _forge_gensym_3", // Address of a 3-byte buffer
+                "peekr",
+                "storew",
+            ].join("\n")
+        )
+    }
 }

forge_core/src/compiler/ast_nodes/lvalue.rs

@@ -19,6 +19,7 @@ impl Compilable for Lvalue {
             Expr::Address(_) |
             Expr::Call(_) |
             Expr::New(_) |
+            Expr::Static(_) |
             Expr::Infix(_, _, _) |
             Expr::String(_) => {
                 Err(CompileError(0, 0, String::from("Not a valid lvalue")))

forge_core/src/compiler/mod.rs

@@ -40,22 +40,32 @@ pub fn build_boot(src: &str) -> Result<Vec<String>, CompileError> {
         // When main returns, just hlt:
         asm.push("hlt".into());
 
-        // Now start dumping compiled objects into there:
+        // Now start dumping compiled objects into there. First functions:
+        for (_, val) in state.functions.iter_mut() {
+            asm.push(format!("{}:", val.label));
+            asm.append(val.preamble.as_mut());
+            asm.append(val.body.as_mut());
+            asm.append(val.outro.as_mut());
+        }
+
+        // Strings:
         for (label, val) in state.strings.iter() {
             asm.push(format!("{}: .db \"{}\\0\"", label, val))
         }
-        for (label, val) in state.global_scope.iter() {
+
+        // Global vars:
+        for (_, val) in state.global_scope.iter() {
             // All global variables are indirect labels; anything in scope that's not that is a const,
             // fn, or string, which we'll emit elsewhere.
             if let Variable::IndirectLabel(label) = val {
                 asm.push(format!("{}: .db 0", label))
             }
         }
-        for (_, val) in state.functions.iter_mut() {
-            asm.push(format!("{}:", val.label));
-            asm.append(val.preamble.as_mut());
-            asm.append(val.body.as_mut());
-            asm.append(val.outro.as_mut());
+
+        // Static buffers:
+        for(label, size) in state.buffers {
+            asm.push(format!("{}: .db 0", label));
+            asm.push(format!(".org {} + {}", label, size));
         }
 
         // Final thing is to place a label for the stack:
@@ -105,7 +115,6 @@ mod test {
             "push stack",
             "call _forge_gensym_2",
             "hlt",
-            "_forge_gensym_1: .db \"blah\\0\"",
             "_forge_gensym_2:",
             "dup",
             "pushr",
@@ -119,6 +128,7 @@ mod test {
             "popr",
             "pop",
             "ret",
+            "_forge_gensym_1: .db \"blah\\0\"",
             "stack: .db 0",
         ].join("\n"))
     }
@@ -132,7 +142,6 @@ mod test {
             "push stack",
             "call _forge_gensym_2",
             "hlt",
-            "_forge_gensym_1: .db 0", // The global var
             "_forge_gensym_2:", // main()
             "dup", "pushr", "pushr", // The frame is zero length; that's a global we're assigning to
             "push 3", // rvalue
@@ -141,6 +150,7 @@ mod test {
             "push 0",
             "_forge_gensym_3:",
             "popr", "pop", "popr", "pop", "ret",
+            "_forge_gensym_1: .db 0", // The global var
             "stack: .db 0",
         ].join("\n"))
     }

forge_core/src/compiler/state.rs

@@ -15,6 +15,8 @@ pub(crate) struct State {
     pub functions: BTreeMap<String, CompiledFn>,
     /// The string table
     pub strings: Vec<(Label, String)>,
+    /// The statically-allocated buffers (size in bytes)
+    pub buffers: Vec<(Label, usize)>,
     /// The functions that have been prototyped but not yet defined
     pub prototypes: Scope,
 }
@@ -52,6 +54,12 @@ impl State {
         sym
     }
 
+    pub(crate) fn add_buffer(&mut self, size: usize) -> Label {
+        let sym = self.gensym();
+        self.buffers.push((sym.clone(), size));
+        sym
+    }
+
     pub(crate) fn declare_function(&mut self, name: &str, _args: Vec<String>) -> Result<(), CompileError> {
         // If it's not already prototyped, gensym a label and put it in the list. If it is, just
         // ignore this (we don't check arity so it's not like the arglist being different matters)

forge_core/src/parser/ast_nodes/expr.rs

@@ -19,6 +19,7 @@ impl AstNode for Expr {
             .map_primary(|term| match term.as_rule() {
                 PestRule::number => Expr::Number(term.into_number()),
                 PestRule::alloc => Expr::New(Expr::from_pair(term.first()).into()),
+                PestRule::static_alloc => Expr::Static(Expr::from_pair(term.first()).into()),
                 PestRule::name => Expr::Name(String::from(term.as_str())),
                 PestRule::expr => Expr::from_pair(term),
                 PestRule::string => Self::String(term.into_quoted_string()),
@@ -275,4 +276,9 @@ mod test {
     fn alloc() {
         assert_eq!(Expr::from_str("new(8)"), Ok(Expr::New(8.into())));
     }
+
+    #[test]
+    fn static_alloc() {
+        assert_eq!(Expr::from_str("static(8)"), Ok(Expr::Static(8.into())));
+    }
 }

forge_core/src/parser/forge.pest

@@ -63,9 +63,9 @@ operator = _{
 }
 
 expr = { prefix* ~ term ~ suffix* ~ (operator ~ prefix* ~ term ~ suffix*)* }
-term = _{ number | alloc | name | "(" ~ expr ~ ")" | string }
+term = _{ number | alloc | static_alloc | name | "(" ~ expr ~ ")" | string }
 alloc = { "new" ~ "(" ~ expr ~ ")" }
-
+static_alloc = { "static" ~ "(" ~ expr ~ ")" }
 
 suffix    = _{ subscript | arglist }
 subscript = { "[" ~ expr ~ "]" }