From 61f31a33a073745be8946d33ecb84206d413c554 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E9=9F=AD=E8=8F=9C=E9=92=9F?= <312780179@qq.com>
Date: Thu, 2 Apr 2026 14:13:59 +0800
Subject: [PATCH] fix: do not update last_opcode_pos when emitting OP_debug

OP_debug is a transparent no-op (0 pop, 0 push) used solely for
debugger breakpoints. Setting last_opcode_pos to point at OP_debug
breaks all peephole optimizations that rely on get_prev_opcode(),
because they see OP_debug instead of the real preceding opcode.

Affected code paths include:
- js_is_live_code(): misidentifies dead code as live
- set_object_name(): fails to match OP_set_name / OP_set_class_name
- lvalue parsing: falls into the default (invalid lvalue) branch
- set_object_name_computed(): fails to rewrite opcodes

This caused CI test failures when OP_debug was always emitted.

Fix: stop updating last_opcode_pos in emit_source_loc(), making
OP_debug transparent to the peephole optimizer, just like
OP_source_loc already is.
---
 quickjs.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/quickjs.c b/quickjs.c
index da222d9d3..1c8e9ab12 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -23184,7 +23184,6 @@ static void emit_source_loc(JSParseState *s)
     dbuf_putc(bc, OP_source_loc);
     dbuf_put_u32(bc, s->token.line_num);
     dbuf_put_u32(bc, s->token.col_num);
-    fd->last_opcode_pos = bc->size;
     dbuf_putc(bc, OP_debug);
 }