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authorVincent Ambo <mail@tazj.in>2022-08-28T20·53+0300
committertazjin <tazjin@tvl.su>2022-09-06T14·58+0000
commitd1798444bec692a608aa93605cbe449d985c3e16 (patch)
tree470d7aeef33079e12d865b89f7797c2b531ca072 /tvix/eval/src/compiler/mod.rs
parent1f37275cfb42994ed23742b80055a7ab0485247d (diff)
feat(tvix/eval): Add Compiler::thunk method for emitting thunks r/4674
The logic in this method is *very* similar to `compile_lambda`. It is
intended to be called around any expression that should be
thunked (such as function applications, attribute set values, etc.).

Change-Id: Idfbb2daa9f4b735095378fb9c39a2fd07c8cff91
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6344
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
Diffstat (limited to 'tvix/eval/src/compiler/mod.rs')
-rw-r--r--tvix/eval/src/compiler/mod.rs37
1 files changed, 36 insertions, 1 deletions
diff --git a/tvix/eval/src/compiler/mod.rs b/tvix/eval/src/compiler/mod.rs
index c9cd66aca78f..7c20307b843b 100644
--- a/tvix/eval/src/compiler/mod.rs
+++ b/tvix/eval/src/compiler/mod.rs
@@ -26,7 +26,7 @@ use std::rc::Rc;
 use crate::chunk::Chunk;
 use crate::errors::{Error, ErrorKind, EvalResult};
 use crate::opcode::{CodeIdx, Count, JumpOffset, OpCode, UpvalueIdx};
-use crate::value::{Closure, Lambda, Value};
+use crate::value::{Closure, Lambda, Thunk, Value};
 use crate::warnings::{EvalWarning, WarningKind};
 
 use self::scope::{Local, LocalIdx, LocalPosition, Scope, Upvalue};
@@ -848,6 +848,41 @@ impl Compiler {
         self.chunk().push_op(OpCode::OpCall);
     }
 
+    /// Compile an expression into a runtime thunk which should be
+    /// lazily evaluated when accessed.
+    // TODO: almost the same as Compiler::compile_lambda; unify?
+    fn thunk<F>(&mut self, slot: Option<LocalIdx>, content: F)
+    where
+        F: FnOnce(&mut Compiler, Option<LocalIdx>),
+    {
+        self.contexts.push(LambdaCtx::new());
+        self.begin_scope();
+        content(self, slot);
+        self.end_scope();
+
+        let thunk = self.contexts.pop().unwrap();
+
+        #[cfg(feature = "disassembler")]
+        {
+            crate::disassembler::disassemble_chunk(&thunk.lambda.chunk);
+        }
+
+        // Emit the thunk directly if it does not close over the
+        // environment.
+        if thunk.lambda.upvalue_count == 0 {
+            self.emit_constant(Value::Thunk(Thunk::new(thunk.lambda)));
+            return;
+        }
+
+        // Otherwise prepare for runtime construction of the thunk.
+        let blueprint_idx = self
+            .chunk()
+            .push_constant(Value::Blueprint(Rc::new(thunk.lambda)));
+
+        self.chunk().push_op(OpCode::OpThunk(blueprint_idx));
+        self.emit_upvalue_data(slot, thunk.scope.upvalues);
+    }
+
     /// Emit the data instructions that the runtime needs to correctly
     /// assemble the provided upvalues array.
     fn emit_upvalue_data(&mut self, slot: Option<LocalIdx>, upvalues: Vec<Upvalue>) {