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Add loop and switch return values (#2828) 

* Add loop and switch return values

* Apply suggestions
pull/2911/head
raskad 1 year ago committed by GitHub
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70b0d49483
commit
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17 changed files with 365 additions and 143 deletions
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  1. 11
      boa_ast/src/statement/mod.rs
  2. 15
      boa_engine/src/bytecompiler/mod.rs
  3. 24
      boa_engine/src/bytecompiler/statement/if.rs
  4. 10
      boa_engine/src/bytecompiler/statement/labelled.rs
  5. 114
      boa_engine/src/bytecompiler/statement/loop.rs
  6. 14
      boa_engine/src/bytecompiler/statement/mod.rs
  7. 10
      boa_engine/src/bytecompiler/statement/switch.rs
  8. 22
      boa_engine/src/bytecompiler/statement/try.rs
  9. 13
      boa_engine/src/bytecompiler/statement/with.rs
  10. 80
      boa_engine/src/vm/call_frame/env_stack.rs
  11. 1
      boa_engine/src/vm/call_frame/mod.rs
  12. 3
      boa_engine/src/vm/code_block.rs
  13. 4
      boa_engine/src/vm/flowgraph/mod.rs
  14. 29
      boa_engine/src/vm/opcode/control_flow/break.rs
  15. 29
      boa_engine/src/vm/opcode/control_flow/continue.rs
  16. 98
      boa_engine/src/vm/opcode/iteration/loop_ops.rs
  17. 17
      boa_engine/src/vm/opcode/mod.rs

11
boa_ast/src/statement/mod.rs
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@ -162,6 +162,17 @@ impl Statement {
_ => false,
}
}
/// Returns `true` if the statement returns a value.
#[inline]
#[must_use]
pub const fn returns_value(&self) -> bool {
match self {
Self::Block(block) if block.statement_list().statements().is_empty() => false,
Self::Empty | Self::Var(_) | Self::Break(_) | Self::Continue(_) => false,
_ => true,
}
}
}
impl ToIndentedString for Statement {

15
boa_engine/src/bytecompiler/mod.rs
Unescape View File

@ -745,8 +745,17 @@ impl<'ctx, 'host> ByteCompiler<'ctx, 'host> {
/// Compile a [`StatementList`].
pub fn compile_statement_list(&mut self, list: &StatementList, use_expr: bool, block: bool) {
if use_expr {
let expr_index = list
let list_until_loop_exit: Vec<_> = list
.statements()
.iter()
.take_while(|item| {
!matches!(
item,
StatementListItem::Statement(Statement::Break(_) | Statement::Continue(_))
)
})
.collect();
let expr_index = list_until_loop_exit
.iter()
.rev()
.skip_while(|item| {
@ -758,6 +767,10 @@ impl<'ctx, 'host> ByteCompiler<'ctx, 'host> {
})
.count();
if expr_index == 0 && !list.statements().is_empty() {
self.emit_opcode(Opcode::PushUndefined);
}
for (i, item) in list.statements().iter().enumerate() {
self.compile_stmt_list_item(item, i + 1 == expr_index, block);
}

24
boa_engine/src/bytecompiler/statement/if.rs
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@ -1,4 +1,4 @@
use crate::bytecompiler::ByteCompiler;
use crate::{bytecompiler::ByteCompiler, vm::Opcode};
use boa_ast::statement::If;
impl ByteCompiler<'_, '_> {
@ -6,18 +6,28 @@ impl ByteCompiler<'_, '_> {
self.compile_expr(node.cond(), true);
let jelse = self.jump_if_false();
self.compile_stmt(node.body(), use_expr);
if !node.body().returns_value() {
self.emit_opcode(Opcode::PushUndefined);
}
self.compile_stmt(node.body(), true);
let exit = self.jump();
self.patch_jump(jelse);
match node.else_node() {
None => {
self.patch_jump(jelse);
self.emit_opcode(Opcode::PushUndefined);
}
Some(else_body) => {
let exit = self.jump();
self.patch_jump(jelse);
self.compile_stmt(else_body, use_expr);
self.patch_jump(exit);
if !else_body.returns_value() {
self.emit_opcode(Opcode::PushUndefined);
}
self.compile_stmt(else_body, true);
}
}
self.patch_jump(exit);
if !use_expr {
self.emit_opcode(Opcode::Pop);
}
}
}

10
boa_engine/src/bytecompiler/statement/labelled.rs
Unescape View File

@ -17,19 +17,19 @@ impl ByteCompiler<'_, '_> {
match labelled.item() {
LabelledItem::Statement(stmt) => match stmt {
Statement::ForLoop(for_loop) => {
self.compile_for_loop(for_loop, Some(labelled.label()));
self.compile_for_loop(for_loop, Some(labelled.label()), use_expr);
}
Statement::ForInLoop(for_in_loop) => {
self.compile_for_in_loop(for_in_loop, Some(labelled.label()));
self.compile_for_in_loop(for_in_loop, Some(labelled.label()), use_expr);
}
Statement::ForOfLoop(for_of_loop) => {
self.compile_for_of_loop(for_of_loop, Some(labelled.label()));
self.compile_for_of_loop(for_of_loop, Some(labelled.label()), use_expr);
}
Statement::WhileLoop(while_loop) => {
self.compile_while_loop(while_loop, Some(labelled.label()));
self.compile_while_loop(while_loop, Some(labelled.label()), use_expr);
}
Statement::DoWhileLoop(do_while_loop) => {
self.compile_do_while_loop(do_while_loop, Some(labelled.label()));
self.compile_do_while_loop(do_while_loop, Some(labelled.label()), use_expr);
}
stmt => self.compile_stmt(stmt, use_expr),
},

114
boa_engine/src/bytecompiler/statement/loop.rs
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@ -14,7 +14,12 @@ use crate::{
};
impl ByteCompiler<'_, '_> {
pub(crate) fn compile_for_loop(&mut self, for_loop: &ForLoop, label: Option<Sym>) {
pub(crate) fn compile_for_loop(
&mut self,
for_loop: &ForLoop,
label: Option<Sym>,
use_expr: bool,
) {
self.push_compile_environment(false);
let push_env = self.emit_opcode_with_two_operands(Opcode::PushDeclarativeEnvironment);
self.push_empty_loop_jump_control();
@ -54,11 +59,8 @@ impl ByteCompiler<'_, '_> {
.expect("jump_control must exist as it was just pushed")
.set_start_address(start_address);
let (continue_start, continue_exit) =
self.emit_opcode_with_two_operands(Opcode::LoopContinue);
self.emit_opcode(Opcode::LoopContinue);
self.patch_jump_with_target(loop_start, start_address);
self.patch_jump_with_target(continue_start, start_address);
if let Some(final_expr) = for_loop.final_expr() {
self.compile_expr(final_expr, false);
@ -73,7 +75,11 @@ impl ByteCompiler<'_, '_> {
}
let exit = self.jump_if_false();
self.compile_stmt(for_loop.body(), false);
if !for_loop.body().returns_value() {
self.emit_opcode(Opcode::PushUndefined);
}
self.compile_stmt(for_loop.body(), true);
self.emit_opcode(Opcode::LoopUpdateReturnValue);
self.emit(Opcode::Jump, &[start_address]);
@ -83,13 +89,21 @@ impl ByteCompiler<'_, '_> {
self.patch_jump(exit);
self.patch_jump(loop_exit);
self.patch_jump(continue_exit);
self.pop_loop_control_info();
self.emit_opcode(Opcode::LoopEnd);
if !use_expr {
self.emit_opcode(Opcode::Pop);
}
self.emit_opcode(Opcode::PopEnvironment);
}
pub(crate) fn compile_for_in_loop(&mut self, for_in_loop: &ForInLoop, label: Option<Sym>) {
pub(crate) fn compile_for_in_loop(
&mut self,
for_in_loop: &ForInLoop,
label: Option<Sym>,
use_expr: bool,
) {
// Handle https://tc39.es/ecma262/#prod-annexB-ForInOfStatement
if let IterableLoopInitializer::Var(var) = for_in_loop.initializer() {
if let Binding::Identifier(ident) = var.binding() {
@ -128,9 +142,7 @@ impl ByteCompiler<'_, '_> {
let (loop_start, exit_label) = self.emit_opcode_with_two_operands(Opcode::LoopStart);
let start_address = self.next_opcode_location();
self.push_loop_control_info_for_of_in_loop(label, start_address);
let (continue_label, cont_exit_label) =
self.emit_opcode_with_two_operands(Opcode::LoopContinue);
self.patch_jump_with_target(continue_label, start_address);
self.emit_opcode(Opcode::LoopContinue);
self.patch_jump_with_target(loop_start, start_address);
self.emit_opcode(Opcode::Pop); // pop the `done` value.
@ -192,7 +204,11 @@ impl ByteCompiler<'_, '_> {
}
}
self.compile_stmt(for_in_loop.body(), false);
if !for_in_loop.body().returns_value() {
self.emit_opcode(Opcode::PushUndefined);
}
self.compile_stmt(for_in_loop.body(), true);
self.emit_opcode(Opcode::LoopUpdateReturnValue);
if let Some(iteration_environment) = iteration_environment {
let env_info = self.pop_compile_environment();
@ -205,17 +221,30 @@ impl ByteCompiler<'_, '_> {
self.patch_jump(exit);
self.patch_jump(exit_label);
self.patch_jump(cont_exit_label);
self.pop_loop_control_info();
self.emit_opcode(Opcode::LoopEnd);
self.emit_opcode(Opcode::RotateRight);
self.emit_u8(4);
self.emit_opcode(Opcode::Pop);
self.emit_opcode(Opcode::Pop);
self.emit_opcode(Opcode::Pop);
let skip_early_exit = self.jump();
self.patch_jump(early_exit);
self.emit_opcode(Opcode::PushUndefined);
self.patch_jump(skip_early_exit);
if !use_expr {
self.emit_opcode(Opcode::Pop);
}
}
pub(crate) fn compile_for_of_loop(&mut self, for_of_loop: &ForOfLoop, label: Option<Sym>) {
pub(crate) fn compile_for_of_loop(
&mut self,
for_of_loop: &ForOfLoop,
label: Option<Sym>,
use_expr: bool,
) {
let initializer_bound_names = match for_of_loop.initializer() {
IterableLoopInitializer::Let(declaration)
| IterableLoopInitializer::Const(declaration) => bound_names(declaration),
@ -248,10 +277,8 @@ impl ByteCompiler<'_, '_> {
let (loop_start, loop_exit) = self.emit_opcode_with_two_operands(Opcode::LoopStart);
let start_address = self.next_opcode_location();
self.push_loop_control_info_for_of_in_loop(label, start_address);
let (cont_label, cont_exit_label) =
self.emit_opcode_with_two_operands(Opcode::LoopContinue);
self.emit_opcode(Opcode::LoopContinue);
self.patch_jump_with_target(loop_start, start_address);
self.patch_jump_with_target(cont_label, start_address);
self.emit_opcode(Opcode::Pop); // pop the `done` value.
self.emit_opcode(Opcode::IteratorNext);
@ -322,7 +349,11 @@ impl ByteCompiler<'_, '_> {
}
}
self.compile_stmt(for_of_loop.body(), false);
if !for_of_loop.body().returns_value() {
self.emit_opcode(Opcode::PushUndefined);
}
self.compile_stmt(for_of_loop.body(), true);
self.emit_opcode(Opcode::LoopUpdateReturnValue);
if let Some(iteration_environment) = iteration_environment {
let env_info = self.pop_compile_environment();
@ -335,62 +366,83 @@ impl ByteCompiler<'_, '_> {
self.patch_jump(exit);
self.patch_jump(loop_exit);
self.patch_jump(cont_exit_label);
self.pop_loop_control_info();
self.emit_opcode(Opcode::LoopEnd);
self.emit_opcode(Opcode::RotateRight);
self.emit_u8(4);
self.iterator_close(for_of_loop.r#await());
if !use_expr {
self.emit_opcode(Opcode::Pop);
}
}
pub(crate) fn compile_while_loop(&mut self, while_loop: &WhileLoop, label: Option<Sym>) {
pub(crate) fn compile_while_loop(
&mut self,
while_loop: &WhileLoop,
label: Option<Sym>,
use_expr: bool,
) {
let (loop_start, loop_exit) = self.emit_opcode_with_two_operands(Opcode::LoopStart);
let start_address = self.next_opcode_location();
let (continue_start, continue_exit) =
self.emit_opcode_with_two_operands(Opcode::LoopContinue);
self.emit_opcode(Opcode::LoopContinue);
self.push_loop_control_info(label, start_address);
self.patch_jump_with_target(loop_start, start_address);
self.patch_jump_with_target(continue_start, start_address);
self.compile_expr(while_loop.condition(), true);
let exit = self.jump_if_false();
self.compile_stmt(while_loop.body(), false);
if !while_loop.body().returns_value() {
self.emit_opcode(Opcode::PushUndefined);
}
self.compile_stmt(while_loop.body(), true);
self.emit_opcode(Opcode::LoopUpdateReturnValue);
self.emit(Opcode::Jump, &[start_address]);
self.patch_jump(exit);
self.patch_jump(loop_exit);
self.patch_jump(continue_exit);
self.pop_loop_control_info();
self.emit_opcode(Opcode::LoopEnd);
if !use_expr {
self.emit_opcode(Opcode::Pop);
}
}
pub(crate) fn compile_do_while_loop(
&mut self,
do_while_loop: &DoWhileLoop,
label: Option<Sym>,
use_expr: bool,
) {
let (loop_start, loop_exit) = self.emit_opcode_with_two_operands(Opcode::LoopStart);
let initial_label = self.jump();
let start_address = self.next_opcode_location();
self.patch_jump_with_target(loop_start, start_address);
self.push_loop_control_info(label, start_address);
let condition_label_address = self.next_opcode_location();
let (continue_start, continue_exit) =
self.emit_opcode_with_two_operands(Opcode::LoopContinue);
self.patch_jump_with_target(continue_start, start_address);
self.emit_opcode(Opcode::LoopContinue);
self.compile_expr(do_while_loop.cond(), true);
let exit = self.jump_if_false();
self.patch_jump(initial_label);
self.compile_stmt(do_while_loop.body(), false);
if !do_while_loop.body().returns_value() {
self.emit_opcode(Opcode::PushUndefined);
}
self.compile_stmt(do_while_loop.body(), true);
self.emit_opcode(Opcode::LoopUpdateReturnValue);
self.emit(Opcode::Jump, &[condition_label_address]);
self.patch_jump(exit);
self.patch_jump(loop_exit);
self.patch_jump(continue_exit);
self.pop_loop_control_info();
self.emit_opcode(Opcode::LoopEnd);
if !use_expr {
self.emit_opcode(Opcode::Pop);
}
}
}

14
boa_engine/src/bytecompiler/statement/mod.rs
Unescape View File

@ -19,19 +19,19 @@ impl ByteCompiler<'_, '_> {
Statement::Var(var) => self.compile_var_decl(var),
Statement::If(node) => self.compile_if(node, use_expr),
Statement::ForLoop(for_loop) => {
self.compile_for_loop(for_loop, None);
self.compile_for_loop(for_loop, None, use_expr);
}
Statement::ForInLoop(for_in_loop) => {
self.compile_for_in_loop(for_in_loop, None);
self.compile_for_in_loop(for_in_loop, None, use_expr);
}
Statement::ForOfLoop(for_of_loop) => {
self.compile_for_of_loop(for_of_loop, None);
self.compile_for_of_loop(for_of_loop, None, use_expr);
}
Statement::WhileLoop(while_loop) => {
self.compile_while_loop(while_loop, None);
self.compile_while_loop(while_loop, None, use_expr);
}
Statement::DoWhileLoop(do_while_loop) => {
self.compile_do_while_loop(do_while_loop, None);
self.compile_do_while_loop(do_while_loop, None, use_expr);
}
Statement::Block(block) => {
self.compile_block(block, use_expr);
@ -46,7 +46,7 @@ impl ByteCompiler<'_, '_> {
self.emit(Opcode::Throw, &[]);
}
Statement::Switch(switch) => {
self.compile_switch(switch);
self.compile_switch(switch, use_expr);
}
Statement::Return(ret) => {
if let Some(expr) = ret.target() {
@ -58,7 +58,7 @@ impl ByteCompiler<'_, '_> {
}
Statement::Try(t) => self.compile_try(t, use_expr),
Statement::Expression(expr) => self.compile_expr(expr, use_expr),
Statement::With(with) => self.compile_with(with),
Statement::With(with) => self.compile_with(with, use_expr),
Statement::Empty => {}
}
}

10
boa_engine/src/bytecompiler/statement/switch.rs
Unescape View File

@ -3,7 +3,7 @@ use boa_ast::statement::Switch;
impl ByteCompiler<'_, '_> {
/// Compile a [`Switch`] `boa_ast` node
pub(crate) fn compile_switch(&mut self, switch: &Switch) {
pub(crate) fn compile_switch(&mut self, switch: &Switch, use_expr: bool) {
self.compile_expr(switch.val(), true);
self.push_compile_environment(false);
@ -43,7 +43,10 @@ impl ByteCompiler<'_, '_> {
label
};
self.patch_jump(label);
self.compile_statement_list(case.body(), false, true);
self.compile_statement_list(case.body(), true, true);
if !case.body().statements().is_empty() {
self.emit_opcode(Opcode::LoopUpdateReturnValue);
}
}
if !default_label_set {
@ -53,6 +56,9 @@ impl ByteCompiler<'_, '_> {
self.pop_switch_control_info();
self.patch_jump(end_label);
self.emit_opcode(Opcode::LoopEnd);
if !use_expr {
self.emit_opcode(Opcode::Pop);
}
let env_info = self.pop_compile_environment();
self.patch_jump_with_target(push_env.0, env_info.num_bindings as u32);

22
boa_engine/src/bytecompiler/statement/try.rs
Unescape View File

@ -20,7 +20,13 @@ impl ByteCompiler<'_, '_> {
}
self.push_try_control_info(t.finally().is_some(), try_start);
self.compile_block(t.block(), use_expr);
self.compile_block(t.block(), true);
if t.block().statement_list().statements().is_empty() {
self.emit_opcode(Opcode::PushUndefined);
}
if !use_expr {
self.emit_opcode(Opcode::Pop);
}
self.emit_opcode(Opcode::TryEnd);
@ -76,12 +82,19 @@ impl ByteCompiler<'_, '_> {
self.emit_opcode(Opcode::Pop);
}
self.compile_block(catch.block(), use_expr);
self.compile_block(catch.block(), true);
if catch.block().statement_list().statements().is_empty() {
self.emit_opcode(Opcode::PushUndefined);
}
if !use_expr {
self.emit_opcode(Opcode::Pop);
}
let env_info = self.pop_compile_environment();
self.patch_jump_with_target(push_env.0, env_info.num_bindings as u32);
self.patch_jump_with_target(push_env.1, env_info.index as u32);
self.emit_opcode(Opcode::PopEnvironment);
if parent_try.finally().is_some() {
self.emit_opcode(Opcode::CatchEnd);
} else {
@ -93,7 +106,10 @@ impl ByteCompiler<'_, '_> {
}
pub(crate) fn compile_finally_stmt(&mut self, finally: &Finally, finally_end_label: Label) {
self.compile_block(finally.block(), false);
self.compile_block(finally.block(), true);
if !finally.block().statement_list().statements().is_empty() {
self.emit_opcode(Opcode::Pop);
}
self.pop_finally_control_info();
self.patch_jump(finally_end_label);

13
boa_engine/src/bytecompiler/statement/with.rs
Unescape View File

@ -3,12 +3,21 @@ use boa_ast::statement::With;
impl ByteCompiler<'_, '_> {
/// Compile a [`With`] `boa_ast` node
pub(crate) fn compile_with(&mut self, with: &With) {
pub(crate) fn compile_with(&mut self, with: &With, use_expr: bool) {
self.compile_expr(with.expression(), true);
self.push_compile_environment(false);
self.emit_opcode(Opcode::PushObjectEnvironment);
self.compile_stmt(with.statement(), false);
if !with.statement().returns_value() {
self.emit_opcode(Opcode::PushUndefined);
}
self.compile_stmt(with.statement(), true);
self.pop_compile_environment();
self.emit_opcode(Opcode::PopEnvironment);
if !use_expr {
self.emit_opcode(Opcode::Pop);
}
}
}

80
boa_engine/src/vm/call_frame/env_stack.rs
Unescape View File

@ -1,11 +1,17 @@
//! Module for implementing a `CallFrame`'s environment stacks
#[derive(Clone, Copy, Debug, PartialEq)]
use crate::JsValue;
use boa_gc::{Finalize, Trace};
#[derive(Clone, Debug, Finalize, Trace)]
pub(crate) enum EnvEntryKind {
Global,
Loop {
/// This is used to keep track of how many iterations a loop has done.
iteration_count: u64,
// This is the latest return value of the loop.
value: JsValue,
},
Try,
Catch,
@ -13,8 +19,22 @@ pub(crate) enum EnvEntryKind {
Labelled,
}
/// The `EnvStackEntry` tracks the environment count and relavant information for the current environment.
#[derive(Copy, Clone, Debug)]
impl PartialEq for EnvEntryKind {
fn eq(&self, other: &Self) -> bool {
matches!(
(self, other),
(Self::Global, Self::Global)
| (Self::Loop { .. }, Self::Loop { .. })
| (Self::Try, Self::Try)
| (Self::Catch, Self::Catch)
| (Self::Finally, Self::Finally)
| (Self::Labelled, Self::Labelled)
)
}
}
/// The `EnvStackEntry` tracks the environment count and relevant information for the current environment.
#[derive(Clone, Debug, Finalize, Trace)]
pub(crate) struct EnvStackEntry {
start: u32,
exit: u32,
@ -46,32 +66,35 @@ impl EnvStackEntry {
}
/// Returns calling `EnvStackEntry` with `kind` field of `Try`.
pub(crate) const fn with_try_flag(mut self) -> Self {
pub(crate) fn with_try_flag(mut self) -> Self {
self.kind = EnvEntryKind::Try;
self
}
/// Returns calling `EnvStackEntry` with `kind` field of `Loop`.
/// And the loop iteration set to zero.
pub(crate) const fn with_loop_flag(mut self, iteration_count: u64) -> Self {
self.kind = EnvEntryKind::Loop { iteration_count };
pub(crate) fn with_loop_flag(mut self, iteration_count: u64) -> Self {
self.kind = EnvEntryKind::Loop {
iteration_count,
value: JsValue::undefined(),
};
self
}
/// Returns calling `EnvStackEntry` with `kind` field of `Catch`.
pub(crate) const fn with_catch_flag(mut self) -> Self {
pub(crate) fn with_catch_flag(mut self) -> Self {
self.kind = EnvEntryKind::Catch;
self
}
/// Returns calling `EnvStackEntry` with `kind` field of `Finally`.
pub(crate) const fn with_finally_flag(mut self) -> Self {
pub(crate) fn with_finally_flag(mut self) -> Self {
self.kind = EnvEntryKind::Finally;
self
}
/// Returns calling `EnvStackEntry` with `kind` field of `Labelled`.
pub(crate) const fn with_labelled_flag(mut self) -> Self {
pub(crate) fn with_labelled_flag(mut self) -> Self {
self.kind = EnvEntryKind::Labelled;
self
}
@ -98,14 +121,31 @@ impl EnvStackEntry {
self.kind == EnvEntryKind::Global
}
/// Returns true if an `EnvStackEntry` is a loop
pub(crate) const fn is_loop_env(&self) -> bool {
matches!(self.kind, EnvEntryKind::Loop { .. })
/// Returns the loop iteration count if `EnvStackEntry` is a loop.
pub(crate) const fn as_loop_iteration_count(&self) -> Option<u64> {
if let EnvEntryKind::Loop {
iteration_count, ..
} = self.kind
{
return Some(iteration_count);
}
None
}
pub(crate) const fn as_loop_iteration_count(self) -> Option<u64> {
if let EnvEntryKind::Loop { iteration_count } = self.kind {
return Some(iteration_count);
/// Increases loop iteration count if `EnvStackEntry` is a loop.
pub(crate) fn increase_loop_iteration_count(&mut self) {
if let EnvEntryKind::Loop {
iteration_count, ..
} = &mut self.kind
{
*iteration_count = iteration_count.wrapping_add(1);
}
}
/// Returns the loop return value if `EnvStackEntry` is a loop.
pub(crate) const fn loop_env_value(&self) -> Option<&JsValue> {
if let EnvEntryKind::Loop { value, .. } = &self.kind {
return Some(value);
}
None
}
@ -151,4 +191,14 @@ impl EnvStackEntry {
pub(crate) fn dec_env_num(&mut self) {
self.env_num -= 1;
}
/// Set the loop return value for the current `EnvStackEntry`.
pub(crate) fn set_loop_return_value(&mut self, value: JsValue) -> bool {
if let EnvEntryKind::Loop { value: v, .. } = &mut self.kind {
*v = value;
true
} else {
false
}
}
}

1
boa_engine/src/vm/call_frame/mod.rs
Unescape View File

@ -28,7 +28,6 @@ pub struct CallFrame {
pub(crate) pop_on_return: usize,
// Tracks the number of environments in environment entry.
// On abrupt returns this is used to decide how many environments need to be pop'ed.
#[unsafe_ignore_trace]
pub(crate) env_stack: Vec<EnvStackEntry>,
pub(crate) param_count: usize,
pub(crate) arg_count: usize,

3
boa_engine/src/vm/code_block.rs
Unescape View File

@ -290,7 +290,6 @@ impl CodeBlock {
| Opcode::CopyDataProperties
| Opcode::Break
| Opcode::Continue
| Opcode::LoopContinue
| Opcode::LoopStart
| Opcode::TryStart
| Opcode::AsyncGeneratorNext
@ -460,6 +459,8 @@ impl CodeBlock {
| Opcode::Return
| Opcode::PopEnvironment
| Opcode::LoopEnd
| Opcode::LoopContinue
| Opcode::LoopUpdateReturnValue
| Opcode::LabelledEnd
| Opcode::CreateForInIterator
| Opcode::GetIterator

4
boa_engine/src/vm/flowgraph/mod.rs
Unescape View File

@ -138,7 +138,7 @@ impl CodeBlock {
graph.add_node(previous_pc, NodeShape::None, label.into(), Color::Red);
graph.add_edge(previous_pc, pc, None, Color::None, EdgeStyle::Line);
}
Opcode::LoopContinue | Opcode::LoopStart => {
Opcode::LoopStart => {
let start_address = self.read::<u32>(pc);
pc += size_of::<u32>();
let end_address = self.read::<u32>(pc);
@ -540,6 +540,8 @@ impl CodeBlock {
| Opcode::This
| Opcode::Super
| Opcode::LoopEnd
| Opcode::LoopContinue
| Opcode::LoopUpdateReturnValue
| Opcode::LabelledEnd
| Opcode::CreateForInIterator
| Opcode::GetIterator

29
boa_engine/src/vm/opcode/control_flow/break.rs
Unescape View File

@ -1,6 +1,6 @@
use crate::{
vm::{call_frame::AbruptCompletionRecord, opcode::Operation, CompletionType},
Context, JsResult,
Context, JsResult, JsValue,
};
/// `Break` implements the Opcode Operation for `Opcode::Break`
@ -17,18 +17,39 @@ impl Operation for Break {
let jump_address = context.vm.read::<u32>();
let target_address = context.vm.read::<u32>();
let value = context.vm.stack.pop().unwrap_or(JsValue::undefined());
// 1. Iterate through Env stack looking for exit address.
let mut envs_to_pop = 0;
while let Some(env_entry) = context.vm.frame().env_stack.last() {
let mut set_loop_result = false;
let mut found_target = false;
for i in (0..context.vm.frame().env_stack.len()).rev() {
if found_target && set_loop_result {
break;
}
let Some(env_entry) = context.vm.frame_mut().env_stack.get_mut(i) else {
break;
};
if found_target {
set_loop_result = env_entry.set_loop_return_value(value.clone());
continue;
}
if (jump_address == env_entry.exit_address())
|| (env_entry.is_finally_env() && jump_address == env_entry.start_address())
{
break;
found_target = true;
set_loop_result = env_entry.set_loop_return_value(value.clone());
continue;
}
// Checks for the break if we have jumped from inside of a finally block
if jump_address == env_entry.exit_address() {
break;
found_target = true;
set_loop_result = env_entry.set_loop_return_value(value.clone());
continue;
}
envs_to_pop += env_entry.env_num();
context.vm.frame_mut().env_stack.pop();

29
boa_engine/src/vm/opcode/control_flow/continue.rs
Unescape View File

@ -1,6 +1,6 @@
use crate::{
vm::{call_frame::AbruptCompletionRecord, opcode::Operation, CompletionType},
Context, JsResult,
Context, JsResult, JsValue,
};
/// `Continue` implements the Opcode Operation for `Opcode::Continue`
@ -21,23 +21,44 @@ impl Operation for Continue {
let jump_address = context.vm.read::<u32>();
let target_address = context.vm.read::<u32>();
let value = context.vm.stack.pop().unwrap_or(JsValue::undefined());
// 1. Iterate through Env stack looking for exit address.
let mut envs_to_pop = 0;
while let Some(env_entry) = context.vm.frame_mut().env_stack.last() {
let mut set_loop_result = false;
let mut found_target = false;
for i in (0..context.vm.frame().env_stack.len()).rev() {
if found_target && set_loop_result {
break;
}
let Some(env_entry) = context.vm.frame_mut().env_stack.get_mut(i) else {
break;
};
if found_target {
set_loop_result = env_entry.set_loop_return_value(value.clone());
continue;
}
// We check two conditions here where continue actually jumps to a higher address.
// 1. When we have reached a finally env that matches the jump address we are moving to.
// 2. When there is no finally, and we have reached the continue location.
if (env_entry.is_finally_env() && jump_address == env_entry.start_address())
|| (jump_address == target_address && jump_address == env_entry.start_address())
{
break;
found_target = true;
set_loop_result = env_entry.set_loop_return_value(value.clone());
continue;
}
envs_to_pop += env_entry.env_num();
// The below check determines whether we have continued from inside of a finally block.
if jump_address > target_address && jump_address == env_entry.exit_address() {
found_target = true;
set_loop_result = env_entry.set_loop_return_value(value.clone());
context.vm.frame_mut().env_stack.pop();
break;
continue;
}
context.vm.frame_mut().env_stack.pop();
}

98
boa_engine/src/vm/opcode/iteration/loop_ops.rs
Unescape View File

@ -26,22 +26,6 @@ impl Operation for LoopStart {
}
}
/// This is a helper function used to clean the loop environment created by the
/// [`LoopStart`] and [`LoopContinue`] opcodes.
fn cleanup_loop_environment(context: &mut Context<'_>) {
let mut envs_to_pop = 0_usize;
while let Some(env_entry) = context.vm.frame_mut().env_stack.pop() {
envs_to_pop += env_entry.env_num();
if env_entry.is_loop_env() {
break;
}
}
let env_truncation_len = context.vm.environments.len().saturating_sub(envs_to_pop);
context.vm.environments.truncate(env_truncation_len);
}
/// `LoopContinue` implements the Opcode Operation for `Opcode::LoopContinue`.
///
/// Operation:
@ -54,48 +38,31 @@ impl Operation for LoopContinue {
const INSTRUCTION: &'static str = "INST - LoopContinue";
fn execute(context: &mut Context<'_>) -> JsResult<CompletionType> {
let start = context.vm.read::<u32>();
let exit = context.vm.read::<u32>();
let mut iteration_count = 0;
// 1. Clean up the previous environment.
if let Some(entry) = context
let env = context
.vm
.frame()
.frame_mut()
.env_stack
.last()
.filter(|entry| entry.exit_address() == exit)
{
let env_truncation_len = context
.vm
.environments
.len()
.saturating_sub(entry.env_num());
context.vm.environments.truncate(env_truncation_len);
.last_mut()
.expect("loop environment must be present");
// Pop loop environment and get it's iteration count.
let previous_entry = context.vm.frame_mut().env_stack.pop();
if let Some(previous_iteration_count) =
previous_entry.and_then(EnvStackEntry::as_loop_iteration_count)
{
iteration_count = previous_iteration_count.wrapping_add(1);
let env_num = env.env_num();
env.clear_env_num();
if let Some(previous_iteration_count) = env.as_loop_iteration_count() {
env.increase_loop_iteration_count();
let max = context.vm.runtime_limits.loop_iteration_limit();
if previous_iteration_count > max {
cleanup_loop_environment(context);
let env_truncation_len = context.vm.environments.len().saturating_sub(env_num);
context.vm.environments.truncate(env_truncation_len);
return Err(JsNativeError::runtime_limit()
.with_message(format!("Maximum loop iteration limit {max} exceeded"))
.into());
}
}
}
// 2. Push a new clean EnvStack.
let entry = EnvStackEntry::new(start, exit).with_loop_flag(iteration_count);
context.vm.frame_mut().env_stack.push(entry);
let env_truncation_len = context.vm.environments.len().saturating_sub(env_num);
context.vm.environments.truncate(env_truncation_len);
Ok(CompletionType::Normal)
}
@ -104,7 +71,7 @@ impl Operation for LoopContinue {
/// `LoopEnd` implements the Opcode Operation for `Opcode::LoopEnd`
///
/// Operation:
/// - Clean up enviroments at the end of a lopp.
/// - Clean up environments at the end of a loop.
#[derive(Debug, Clone, Copy)]
pub(crate) struct LoopEnd;
@ -113,7 +80,44 @@ impl Operation for LoopEnd {
const INSTRUCTION: &'static str = "INST - LoopEnd";
fn execute(context: &mut Context<'_>) -> JsResult<CompletionType> {
cleanup_loop_environment(context);
let mut envs_to_pop = 0_usize;
while let Some(env_entry) = context.vm.frame_mut().env_stack.pop() {
envs_to_pop += env_entry.env_num();
if let Some(value) = env_entry.loop_env_value() {
context.vm.push(value.clone());
break;
}
}
let env_truncation_len = context.vm.environments.len().saturating_sub(envs_to_pop);
context.vm.environments.truncate(env_truncation_len);
Ok(CompletionType::Normal)
}
}
/// `LoopUpdateReturnValue` implements the Opcode Operation for `Opcode::LoopUpdateReturnValue`
///
/// Operation:
/// - Update the return value of a loop.
#[derive(Debug, Clone, Copy)]
pub(crate) struct LoopUpdateReturnValue;
impl Operation for LoopUpdateReturnValue {
const NAME: &'static str = "LoopUpdateReturnValue";
const INSTRUCTION: &'static str = "INST - LoopUpdateReturnValue";
fn execute(context: &mut Context<'_>) -> JsResult<CompletionType> {
let value = context.vm.pop();
context
.vm
.frame_mut()
.env_stack
.last_mut()
.expect("loop environment must be present")
.set_loop_return_value(value);
Ok(CompletionType::Normal)
}
}

17
boa_engine/src/vm/opcode/mod.rs
Unescape View File

@ -1168,14 +1168,14 @@ generate_impl! {
///
/// Operands: Jump Address: u32, Target address: u32
///
/// Stack: **=>**
/// Stack: loop_return_value **=>**
Break,
/// Sets the `AbruptCompletionRecord` for a delayed continue
///
/// Operands: Jump Address: u32, Target address: u32,
///
/// Stack: **=>**
/// Stack: loop_return_value **=>**
Continue,
/// Pops value converts it to boolean and pushes it back.
@ -1370,18 +1370,25 @@ generate_impl! {
/// Clean up environments when a loop continues.
///
/// Operands: Start Address: `u32`, Exit Address: `u32`
/// Operands:
///
/// Stack: **=>**
LoopContinue,
/// Clean up environments at the end of a loop.
/// Clean up environments at the end of a loop and return it's value.
///
/// Operands:
///
/// Stack: **=>**
/// Stack: **=>** value
LoopEnd,
/// Update the return value of a loop.
///
/// Operands:
///
/// Stack: loop_return_value **=>**
LoopUpdateReturnValue,
/// Push labelled start marker.
///
/// Operands: Exit Address: u32,

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