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Fix incorrect `LoopContinue` instruction in while-do loops (#2866)

While working on #2857 I discovered that while generating the bytecode for `do-while` loops we were emitting an orphan `LoopContinue` that is never executed, which was preventing the error to be thrown when max loop iteration is reached.

This can more easily be identified with it's flowgraph : (`do { 1; } while(0) `)

Main:

<details>
<img src="https://user-images.githubusercontent.com/8566042/233908011-247313bc-6435-4622-8ecb-f469d9eaf850.png">
</details>

With this PR:

<details>
<img src="https://user-images.githubusercontent.com/8566042/233908030-3552636e-f09c-4c5e-8c7c-1ecfa0024dfe.png">
</details>
pull/2871/head
Haled Odat 2 years ago
parent
commit
41448e13f9
  1. 6
      boa_engine/src/bytecompiler/statement/loop.rs

6
boa_engine/src/bytecompiler/statement/loop.rs

@ -392,13 +392,13 @@ impl ByteCompiler<'_, '_> {
let initial_label = self.jump(); let initial_label = self.jump();
let start_address = self.next_opcode_location(); let start_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.patch_jump_with_target(loop_start, start_address); self.patch_jump_with_target(loop_start, start_address);
self.push_loop_control_info(label, start_address); self.push_loop_control_info(label, start_address);
let condition_label_address = self.next_opcode_location(); 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.compile_expr(do_while_loop.cond(), true); self.compile_expr(do_while_loop.cond(), true);
let exit = self.jump_if_false(); let exit = self.jump_if_false();

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