refactor(levm): skip redundant bytecode bounds check in JUMP validation

crates/common/types/account.rs

@@ -55,6 +55,19 @@ impl Code {
         }
     }
 
+    /// Returns true iff `target` indexes a valid JUMPDEST in this bytecode.
+    ///
+    /// `jump_targets` is built by [`Self::compute_jump_targets`] and contains every
+    /// position whose byte is `JUMPDEST` (0x5B) and that is not inside a PUSH
+    /// literal; its entries are `u32` (bytecode length fits in `u32`).
+    ///
+    /// Uses `u32::try_from` rather than `target as u32` so that a `target` with
+    /// nonzero upper bits (e.g. `2^32 + k` for a real JUMPDEST at `k`) is
+    /// rejected instead of aliasing down to a valid-looking low-32-bit index.
+    pub fn is_valid_jump_target(&self, target: usize) -> bool {
+        u32::try_from(target).is_ok_and(|t| self.jump_targets.binary_search(&t).is_ok())
+    }
+
     fn compute_jump_targets(code: &[u8]) -> Vec<u32> {
         debug_assert!(code.len() <= u32::MAX as usize);
         let mut targets = Vec::new();

crates/vm/levm/src/opcode_handlers/stack_memory_storage_flow.rs

@@ -23,7 +23,6 @@ use crate::{
     gas_cost::{self, SSTORE_STIPEND, STATE_GAS_STORAGE_SET},
     memory::calculate_memory_size,
     opcode_handlers::OpcodeHandler,
-    opcodes::Opcode,
     utils::{size_offset_to_usize, u256_to_usize},
     vm::VM,
 };
@@ -417,22 +416,7 @@ fn jump(vm: &mut VM<'_>, target: usize) -> Result<(), VMError> {
     // Check target address validity.
     //   - Target bytecode has to be a JUMPDEST.
     //   - Target address must not be blacklisted (aka. the JUMPDEST must not be part of a literal).
-    #[expect(clippy::as_conversions, reason = "safe")]
-    if vm
-        .current_call_frame
-        .bytecode
-        .bytecode
-        .get(target)
-        .is_some_and(|&value| {
-            value == Opcode::JUMPDEST as u8
-                && vm
-                    .current_call_frame
-                    .bytecode
-                    .jump_targets
-                    .binary_search(&(target as u32))
-                    .is_ok()
-        })
-    {
+    if vm.current_call_frame.bytecode.is_valid_jump_target(target) {
         // Update PC and skip the JUMPDEST instruction.
         vm.current_call_frame.pc = target.wrapping_add(1);
         vm.current_call_frame