Split vm/opcode into modules (#2343)

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Hi!

This isn't really related to a pull request that I know of. I was trying to better wrap my head around Boa's VM and thought I'd break it apart so that the file wasn't 2500+ lines. I figured I'd submit it as a draft and get feedback/see if anyone was interested in it. The way the modules were broken apart was primarily based off the opcode name (`GetFunction` & `GetFunctionAsync` -> `./get/function.rs`).

It changes the following:

- Adds an `Operation` trait to opcode/mod.rs
- Implements `Operation` for each Opcode variant, moving the executable instruction code from `vm/mod.rs` to the respective module



Co-authored-by: raskad <[email protected]>

boa_engine/src/vm/opcode/await_stm/mod.rs

@@ -0,0 +1,119 @@
+use crate::{
+    builtins::{JsArgs, Promise},
+    object::FunctionBuilder,
+    vm::{call_frame::GeneratorResumeKind, opcode::Operation, ShouldExit},
+    Context, JsResult, JsValue,
+};
+
+/// `Await` implements the Opcode Operation for `Opcode::Await`
+///
+/// Operation:
+///  - Stops the current Async function and schedules it to resume later.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub(crate) struct Await;
+
+impl Operation for Await {
+    const NAME: &'static str = "Await";
+    const INSTRUCTION: &'static str = "INST - Await";
+
+    fn execute(context: &mut Context) -> JsResult<ShouldExit> {
+        let value = context.vm.pop();
+
+        // 2. Let promise be ? PromiseResolve(%Promise%, value).
+        let promise = Promise::promise_resolve(
+            context.intrinsics().constructors().promise().constructor(),
+            value,
+            context,
+        )?;
+
+        // 3. Let fulfilledClosure be a new Abstract Closure with parameters (value) that captures asyncContext and performs the following steps when called:
+        // 4. Let onFulfilled be CreateBuiltinFunction(fulfilledClosure, 1, "", « »).
+        let on_fulfilled = FunctionBuilder::closure_with_captures(
+            context,
+            |_this, args, (environment, stack, frame), context| {
+                // a. Let prevContext be the running execution context.
+                // b. Suspend prevContext.
+                // c. Push asyncContext onto the execution context stack; asyncContext is now the running execution context.
+                // d. Resume the suspended evaluation of asyncContext using NormalCompletion(value) as the result of the operation that suspended it.
+                // e. Assert: When we reach this step, asyncContext has already been removed from the execution context stack and prevContext is the currently running execution context.
+                // f. Return undefined.
+
+                std::mem::swap(&mut context.realm.environments, environment);
+                std::mem::swap(&mut context.vm.stack, stack);
+                context.vm.push_frame(frame.clone());
+
+                context.vm.frame_mut().generator_resume_kind = GeneratorResumeKind::Normal;
+                context.vm.push(args.get_or_undefined(0));
+                context.run()?;
+
+                *frame = context
+                    .vm
+                    .pop_frame()
+                    .expect("generator call frame must exist");
+                std::mem::swap(&mut context.realm.environments, environment);
+                std::mem::swap(&mut context.vm.stack, stack);
+
+                Ok(JsValue::undefined())
+            },
+            (
+                context.realm.environments.clone(),
+                context.vm.stack.clone(),
+                context.vm.frame().clone(),
+            ),
+        )
+        .name("")
+        .length(1)
+        .build();
+
+        // 5. Let rejectedClosure be a new Abstract Closure with parameters (reason) that captures asyncContext and performs the following steps when called:
+        // 6. Let onRejected be CreateBuiltinFunction(rejectedClosure, 1, "", « »).
+        let on_rejected = FunctionBuilder::closure_with_captures(
+            context,
+            |_this, args, (environment, stack, frame), context| {
+                // a. Let prevContext be the running execution context.
+                // b. Suspend prevContext.
+                // c. Push asyncContext onto the execution context stack; asyncContext is now the running execution context.
+                // d. Resume the suspended evaluation of asyncContext using ThrowCompletion(reason) as the result of the operation that suspended it.
+                // e. Assert: When we reach this step, asyncContext has already been removed from the execution context stack and prevContext is the currently running execution context.
+                // f. Return undefined.
+
+                std::mem::swap(&mut context.realm.environments, environment);
+                std::mem::swap(&mut context.vm.stack, stack);
+                context.vm.push_frame(frame.clone());
+
+                context.vm.frame_mut().generator_resume_kind = GeneratorResumeKind::Throw;
+                context.vm.push(args.get_or_undefined(0));
+                context.run()?;
+
+                *frame = context
+                    .vm
+                    .pop_frame()
+                    .expect("generator call frame must exist");
+                std::mem::swap(&mut context.realm.environments, environment);
+                std::mem::swap(&mut context.vm.stack, stack);
+
+                Ok(JsValue::undefined())
+            },
+            (
+                context.realm.environments.clone(),
+                context.vm.stack.clone(),
+                context.vm.frame().clone(),
+            ),
+        )
+        .name("")
+        .length(1)
+        .build();
+
+        // 7. Perform PerformPromiseThen(promise, onFulfilled, onRejected).
+        promise
+            .as_object()
+            .expect("promise was not an object")
+            .borrow_mut()
+            .as_promise_mut()
+            .expect("promise was not a promise")
+            .perform_promise_then(&on_fulfilled.into(), &on_rejected.into(), None, context);
+
+        context.vm.push(JsValue::undefined());
+        Ok(ShouldExit::Await)
+    }
+}

boa_engine/src/vm/opcode/binary_ops/logical.rs

@@ -0,0 +1,70 @@
+use crate::{
+    vm::{opcode::Operation, ShouldExit},
+    Context, JsResult,
+};
+
+/// `LogicalAnd` implements the Opcode Operation for `Opcode::LogicalAnd`
+///
+/// Operation:
+///  - Binary logical `&&` operation
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub(crate) struct LogicalAnd;
+
+impl Operation for LogicalAnd {
+    const NAME: &'static str = "LogicalAnd";
+    const INSTRUCTION: &'static str = "INST - LogicalAnd";
+
+    fn execute(context: &mut Context) -> JsResult<ShouldExit> {
+        let exit = context.vm.read::<u32>();
+        let lhs = context.vm.pop();
+        if !lhs.to_boolean() {
+            context.vm.frame_mut().pc = exit as usize;
+            context.vm.push(lhs);
+        }
+        Ok(ShouldExit::False)
+    }
+}
+
+/// `LogicalOr` implements the Opcode Operation for `Opcode::LogicalOr`
+///
+/// Operation:
+///  - Binary logical `||` operation
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub(crate) struct LogicalOr;
+
+impl Operation for LogicalOr {
+    const NAME: &'static str = "LogicalOr";
+    const INSTRUCTION: &'static str = "INST - LogicalOr";
+
+    fn execute(context: &mut Context) -> JsResult<ShouldExit> {
+        let exit = context.vm.read::<u32>();
+        let lhs = context.vm.pop();
+        if lhs.to_boolean() {
+            context.vm.frame_mut().pc = exit as usize;
+            context.vm.push(lhs);
+        }
+        Ok(ShouldExit::False)
+    }
+}
+
+/// `Coalesce` implements the Opcode Operation for `Opcode::Coalesce`
+///
+/// Operation:
+///  - Binary logical `||` operation
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub(crate) struct Coalesce;
+
+impl Operation for Coalesce {
+    const NAME: &'static str = "Coalesce";
+    const INSTRUCTION: &'static str = "INST - Coalesce";
+
+    fn execute(context: &mut Context) -> JsResult<ShouldExit> {
+        let exit = context.vm.read::<u32>();
+        let lhs = context.vm.pop();
+        if !lhs.is_null_or_undefined() {
+            context.vm.frame_mut().pc = exit as usize;
+            context.vm.push(lhs);
+        }
+        Ok(ShouldExit::False)
+    }
+}

boa_engine/src/vm/opcode/binary_ops/macro_defined.rs

@@ -0,0 +1,46 @@
+use crate::{
+    vm::{opcode::Operation, ShouldExit},
+    Context, JsResult,
+};
+
+macro_rules! implement_bin_ops {
+    ($name:ident, $op:ident, $doc_string:literal) => {
+        #[doc= concat!("`", stringify!($name), "` implements the OpCode Operation for `Opcode::", stringify!($name), "`\n")]
+        #[doc= "\n"]
+        #[doc="Operation:\n"]
+        #[doc= concat!(" - ", $doc_string)]
+        #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+        pub(crate) struct $name;
+
+        impl Operation for $name {
+            const NAME: &'static str = stringify!($name);
+            const INSTRUCTION: &'static str = stringify!("INST - " + $name);
+
+            fn execute(context: &mut Context) -> JsResult<ShouldExit> {
+                let rhs = context.vm.pop();
+                let lhs = context.vm.pop();
+                let value = lhs.$op(&rhs, context)?;
+                context.vm.push(value);
+                Ok(ShouldExit::False)
+            }
+        }
+    };
+}
+
+implement_bin_ops!(Add, add, "Binary `+` operator.");
+implement_bin_ops!(Sub, sub, "Binary `-` operator.");
+implement_bin_ops!(Mul, mul, "Binary `*` operator.");
+implement_bin_ops!(Div, div, "Binary `/` operator.");
+implement_bin_ops!(Pow, pow, "Binary `**` operator.");
+implement_bin_ops!(Mod, rem, "Binary `%` operator.");
+implement_bin_ops!(BitAnd, bitand, "Binary `&` operator.");
+implement_bin_ops!(BitOr, bitor, "Binary `|` operator.");
+implement_bin_ops!(BitXor, bitxor, "Binary `^` operator.");
+implement_bin_ops!(ShiftLeft, shl, "Binary `<<` operator.");
+implement_bin_ops!(ShiftRight, shr, "Binary `>>` operator.");
+implement_bin_ops!(UnsignedShiftRight, ushr, "Binary `>>>` operator.");
+implement_bin_ops!(Eq, equals, "Binary `==` operator.");
+implement_bin_ops!(GreaterThan, gt, "Binary `>` operator.");
+implement_bin_ops!(GreaterThanOrEq, ge, "Binary `>=` operator.");
+implement_bin_ops!(LessThan, lt, "Binary `<` operator.");
+implement_bin_ops!(LessThanOrEq, le, "Binary `<=` operator.");

boa_engine/src/vm/opcode/binary_ops/mod.rs

@@ -0,0 +1,120 @@
+use crate::{
+    error::JsNativeError,
+    vm::{opcode::Operation, ShouldExit},
+    Context, JsResult,
+};
+
+pub(crate) mod logical;
+pub(crate) mod macro_defined;
+
+pub(crate) use logical::*;
+pub(crate) use macro_defined::*;
+
+/// `NotEq` implements the Opcode Operation for `Opcode::NotEq`
+///
+/// Operation:
+///  - Binary `!=` operation
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub(crate) struct NotEq;
+
+impl Operation for NotEq {
+    const NAME: &'static str = "NotEq";
+    const INSTRUCTION: &'static str = "INST - NotEq";
+
+    fn execute(context: &mut Context) -> JsResult<ShouldExit> {
+        let rhs = context.vm.pop();
+        let lhs = context.vm.pop();
+        let value = !lhs.equals(&rhs, context)?;
+        context.vm.push(value);
+        Ok(ShouldExit::False)
+    }
+}
+
+/// `StrictEq` implements the Opcode Operation for `Opcode::StrictEq`
+///
+/// Operation:
+///  - Binary `===` operation
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub(crate) struct StrictEq;
+
+impl Operation for StrictEq {
+    const NAME: &'static str = "StrictEq";
+    const INSTRUCTION: &'static str = "INST - StrictEq";
+
+    fn execute(context: &mut Context) -> JsResult<ShouldExit> {
+        let rhs = context.vm.pop();
+        let lhs = context.vm.pop();
+        context.vm.push(lhs.strict_equals(&rhs));
+        Ok(ShouldExit::False)
+    }
+}
+
+/// `StrictNotEq` implements the Opcode Operation for `Opcode::StrictNotEq`
+///
+/// Operation:
+///  - Binary `!==` operation
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub(crate) struct StrictNotEq;
+
+impl Operation for StrictNotEq {
+    const NAME: &'static str = "StrictNotEq";
+    const INSTRUCTION: &'static str = "INST - StrictNotEq";
+
+    fn execute(context: &mut Context) -> JsResult<ShouldExit> {
+        let rhs = context.vm.pop();
+        let lhs = context.vm.pop();
+        context.vm.push(!lhs.strict_equals(&rhs));
+        Ok(ShouldExit::False)
+    }
+}
+
+/// `In` implements the Opcode Operation for `Opcode::In`
+///
+/// Operation:
+///  - Binary `in` operation
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub(crate) struct In;
+
+impl Operation for In {
+    const NAME: &'static str = "In";
+    const INSTRUCTION: &'static str = "INST - In";
+
+    fn execute(context: &mut Context) -> JsResult<ShouldExit> {
+        let rhs = context.vm.pop();
+        let lhs = context.vm.pop();
+
+        if !rhs.is_object() {
+            return Err(JsNativeError::typ()
+                .with_message(format!(
+                    "right-hand side of 'in' should be an object, got {}",
+                    rhs.type_of().to_std_string_escaped()
+                ))
+                .into());
+        }
+        let key = lhs.to_property_key(context)?;
+        let value = context.has_property(&rhs, &key)?;
+        context.vm.push(value);
+        Ok(ShouldExit::False)
+    }
+}
+
+/// `InstanceOf` implements the Opcode Operation for `Opcode::InstanceOf`
+///
+/// Operation:
+///  - Binary `instanceof` operation
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub(crate) struct InstanceOf;
+
+impl Operation for InstanceOf {
+    const NAME: &'static str = "InstanceOf";
+    const INSTRUCTION: &'static str = "INST - InstanceOf";
+
+    fn execute(context: &mut Context) -> JsResult<ShouldExit> {
+        let target = context.vm.pop();
+        let v = context.vm.pop();
+        let value = v.instance_of(&target, context)?;
+
+        context.vm.push(value);
+        Ok(ShouldExit::False)
+    }
+}