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Refactor Context::run()
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@HalidOdat
HalidOdat committed Oct 17, 2023
1 parent ce7cd81 commit 3c398d2
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Showing 2 changed files with 79 additions and 82 deletions.
29 changes: 29 additions & 0 deletions boa_engine/src/error.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -379,6 +379,13 @@ impl JsError {
}
self
}

/// Is the [`JsError`] not catchable in JavaScript.
#[inline]
pub(crate) fn is_non_catchable(&self) -> bool {
self.as_native()
.map_or(false, JsNativeError::is_non_catchable)
}
}

impl From<boa_parser::Error> for JsError {
Expand Down Expand Up @@ -873,6 +880,12 @@ impl JsNativeError {
self.realm = Some(realm);
self
}

/// Is the [`JsNativeError`] not catchable in JavaScript.
#[inline]
pub(crate) fn is_non_catchable(&self) -> bool {
self.kind.is_non_catchable()
}
}

impl From<boa_parser::Error> for JsNativeError {
Expand Down Expand Up @@ -978,6 +991,22 @@ pub enum JsNativeErrorKind {
RuntimeLimit,
}

impl JsNativeErrorKind {
/// Is the [`JsNativeErrorKind`] not catchable in JavaScript.
#[inline]
pub(crate) fn is_non_catchable(&self) -> bool {
#[cfg(feature = "fuzz")]
{
matches!(self, Self::NoInstructionsRemain | Self::RuntimeLimit)
}

#[cfg(not(feature = "fuzz"))]
{
matches!(self, Self::RuntimeLimit)
}
}
}

impl PartialEq<ErrorKind> for JsNativeErrorKind {
fn eq(&self, other: &ErrorKind) -> bool {
matches!(
Expand Down
132 changes: 50 additions & 82 deletions boa_engine/src/vm/mod.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,7 @@
use crate::{
environments::EnvironmentStack, realm::Realm, script::Script, vm::code_block::Readable,
Context, JsError, JsNativeError, JsNativeErrorKind, JsObject, JsResult, JsValue, Module,
Context, JsError, JsNativeError, JsObject, JsResult, JsValue, Module,
};

use boa_gc::{custom_trace, Finalize, Trace};
Expand Down Expand Up @@ -398,9 +398,46 @@ impl Context<'_> {
#[cfg(not(feature = "trace"))]
let result = self.execute_instruction();

let result = match result {
Ok(result) => result,
Err(err) => {
// If we hit the execution step limit, bubble up the error to the
// (Rust) caller instead of trying to handle as an exception.
if err.is_non_catchable() {
let mut fp = self.vm.stack.len();
let mut env_fp = self.vm.environments.len();
while let Some(frame) = self.vm.frames.last() {
if frame.exit_early() {
break;
}

fp = frame.fp as usize;
env_fp = frame.env_fp as usize;
self.vm.pop_frame();
}
self.vm.environments.truncate(env_fp);
self.vm.stack.truncate(fp);
return CompletionRecord::Throw(err);
}

// Note: -1 because we increment after fetching the opcode.
let pc = self.vm.frame().pc.saturating_sub(1);
if self.vm.handle_exception_at(pc) {
self.vm.pending_exception = Some(err);
continue;
}

// Inject realm before crossing the function boundry
let err = err.inject_realm(self.realm().clone());

self.vm.pending_exception = Some(err);
CompletionType::Throw
}
};

match result {
Ok(CompletionType::Normal) => {}
Ok(CompletionType::Return) => {
CompletionType::Normal => {}
CompletionType::Return => {
self.vm.stack.truncate(self.vm.frame().fp as usize);

let result = self.vm.take_return_value();
Expand All @@ -411,10 +448,12 @@ impl Context<'_> {
self.vm.push(result);
self.vm.pop_frame();
}
Ok(CompletionType::Throw) => {
self.vm.stack.truncate(self.vm.frame().fp as usize);

CompletionType::Throw => {
let mut fp = self.vm.frame().fp;
let mut env_fp = self.vm.frame().env_fp;
if self.vm.frame().exit_early() {
self.vm.environments.truncate(env_fp as usize);
self.vm.stack.truncate(fp as usize);
return CompletionRecord::Throw(
self.vm
.pending_exception
Expand All @@ -426,8 +465,9 @@ impl Context<'_> {
self.vm.pop_frame();

while let Some(frame) = self.vm.frames.last_mut() {
fp = frame.fp;
env_fp = frame.fp;
let pc = frame.pc;
let fp = frame.fp;
let exit_early = frame.exit_early();

if self.vm.handle_exception_at(pc) {
Expand All @@ -443,12 +483,13 @@ impl Context<'_> {
);
}

self.vm.stack.truncate(fp as usize);
self.vm.pop_frame();
}
self.vm.environments.truncate(env_fp as usize);
self.vm.stack.truncate(fp as usize);
}
// Early return immediately.
Ok(CompletionType::Yield) => {
CompletionType::Yield => {
let result = self.vm.take_return_value();
if self.vm.frame().exit_early() {
return CompletionRecord::Return(result);
Expand All @@ -457,79 +498,6 @@ impl Context<'_> {
self.vm.push(result);
self.vm.pop_frame();
}
Err(err) => {
if let Some(native_error) = err.as_native() {
// If we hit the execution step limit, bubble up the error to the
// (Rust) caller instead of trying to handle as an exception.
match native_error.kind {
#[cfg(feature = "fuzz")]
JsNativeErrorKind::NoInstructionsRemain => {
self.vm
.environments
.truncate(self.vm.frame().env_fp as usize);
self.vm.stack.truncate(self.vm.frame().fp as usize);
return CompletionRecord::Throw(err);
}
JsNativeErrorKind::RuntimeLimit => {
let mut fp = self.vm.stack.len();
let mut env_fp = self.vm.environments.len();
while let Some(frame) = self.vm.frames.last() {
if frame.exit_early() {
break;
}

fp = frame.fp as usize;
env_fp = frame.env_fp as usize;
self.vm.pop_frame();
}
self.vm.environments.truncate(env_fp);
self.vm.stack.truncate(fp);
return CompletionRecord::Throw(err);
}
_ => {}
}
}

// Note: -1 because we increment after fetching the opcode.
let pc = self.vm.frame().pc.saturating_sub(1);
if self.vm.handle_exception_at(pc) {
self.vm.pending_exception = Some(err);
continue;
}

if self.vm.frame().exit_early() {
self.vm
.environments
.truncate(self.vm.frame().env_fp as usize);
self.vm.stack.truncate(self.vm.frame().fp as usize);
return CompletionRecord::Throw(err);
}

// Inject realm before crossing the function boundry
let err = err.inject_realm(self.realm().clone());

self.vm.pop_frame();

while let Some(frame) = self.vm.frames.last_mut() {
let pc = frame.pc;
let fp = frame.fp;
let env_fp = frame.env_fp;
let exit_early = frame.exit_early();

if self.vm.handle_exception_at(pc) {
self.vm.pending_exception = Some(err);
continue 'instruction;
}

if exit_early {
return CompletionRecord::Throw(err);
}

self.vm.environments.truncate(env_fp as usize);
self.vm.stack.truncate(fp as usize);
self.vm.pop_frame();
}
}
}
}
}
Expand Down

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