chore(tvix/eval): thread a codemap::File reference to the compiler r/4711

This instantiates a codemap outside of the compiler and passes a
reference to the file currently under compilation to it. Note that the
"file" might just be a REPL line.

Change-Id: I131ae1ddb6d718e1374750da9ba0b99608c6058d
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6378
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>

2 files changed, 21 insertions, 5 deletions

diff --git a/tvix/eval/src/compiler/mod.rs b/tvix/eval/src/compiler/mod.rs
index c9bbd8171d4a..522f1a445913 100644
--- a/tvix/eval/src/compiler/mod.rs
+++ b/tvix/eval/src/compiler/mod.rs
@@ -59,7 +59,7 @@ impl LambdaCtx {
 /// implicitly be resolvable in the global scope.
 type GlobalsMap = HashMap<&'static str, Rc<dyn Fn(&mut Compiler)>>;
 
-struct Compiler {
+struct Compiler<'code> {
     contexts: Vec<LambdaCtx>,
     warnings: Vec<EvalWarning>,
     errors: Vec<Error>,
@@ -72,11 +72,16 @@ struct Compiler {
     /// an identifier is resolved against the scope poisoning logic,
     /// and a function that should emit code for the token.
     globals: GlobalsMap,
+
+    /// File reference in the codemap contains all known source code
+    /// and is used to track the spans from which instructions where
+    /// derived.
+    file: &'code codemap::File,
 }
 
 // Helper functions for emitting code and metadata to the internal
 // structures of the compiler.
-impl Compiler {
+impl Compiler<'_> {
     fn context(&self) -> &LambdaCtx {
         &self.contexts[self.contexts.len() - 1]
     }
@@ -110,7 +115,7 @@ impl Compiler {
 }
 
 // Actual code-emitting AST traversal methods.
-impl Compiler {
+impl Compiler<'_> {
     fn compile(&mut self, slot: Option<LocalIdx>, expr: ast::Expr) {
         match expr {
             ast::Expr::Literal(literal) => self.compile_literal(literal),
@@ -1257,9 +1262,10 @@ fn prepare_globals(additional: HashMap<&'static str, Value>) -> GlobalsMap {
     globals
 }
 
-pub fn compile(
+pub fn compile<'code>(
     expr: ast::Expr,
     location: Option<PathBuf>,
+    file: &'code codemap::File,
     globals: HashMap<&'static str, Value>,
 ) -> EvalResult<CompilationOutput> {
     let mut root_dir = match location {
@@ -1278,6 +1284,7 @@ pub fn compile(
 
     let mut c = Compiler {
         root_dir,
+        file,
         globals: prepare_globals(globals),
         contexts: vec![LambdaCtx::new()],
         warnings: vec![],
diff --git a/tvix/eval/src/eval.rs b/tvix/eval/src/eval.rs
index d61e51e6afc2..98e7520e8b2e 100644
--- a/tvix/eval/src/eval.rs
+++ b/tvix/eval/src/eval.rs
@@ -7,6 +7,15 @@ use crate::{
 };
 
 pub fn interpret(code: &str, location: Option<PathBuf>) -> EvalResult<Value> {
+    let mut codemap = codemap::CodeMap::new();
+    let file = codemap.add_file(
+        location
+            .as_ref()
+            .map(|p| p.to_string_lossy().to_string())
+            .unwrap_or_else(|| "<repl>".into()),
+        code.into(),
+    );
+
     let parsed = rnix::ast::Root::parse(code);
     let errors = parsed.errors();
 
@@ -27,7 +36,7 @@ pub fn interpret(code: &str, location: Option<PathBuf>) -> EvalResult<Value> {
         println!("{:?}", root_expr);
     }
 
-    let result = crate::compiler::compile(root_expr, location, global_builtins())?;
+    let result = crate::compiler::compile(root_expr, location, &file, global_builtins())?;
 
     #[cfg(feature = "disassembler")]
     crate::disassembler::disassemble_chunk(&result.lambda.chunk);