diff --git a/Cargo.toml b/Cargo.toml
index 0683fa1..6024ee0 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -19,7 +19,7 @@ rustdoc-args = ["--cfg", "docsrs"]
 default = ["allocator", "ckb-types", "libc", "calc-hash"]
 calc-hash = ["ckb-types/calc-hash"]
 allocator = ["buddy-alloc"]
-simulator = ["ckb-x64-simulator"]
+native-simulator = ["ckb-x64-simulator"]
 dlopen-c = ["libc"]
 build-with-clang = []
 libc = []
diff --git a/contracts/exec-callee/Cargo.toml b/contracts/exec-callee/Cargo.toml
index 4389412..a6fc783 100644
--- a/contracts/exec-callee/Cargo.toml
+++ b/contracts/exec-callee/Cargo.toml
@@ -6,7 +6,7 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [features]
-simulator = ["ckb-std/simulator"]
+native-simulator = ["ckb-std/native-simulator"]
 
 [dependencies]
 ckb-std = { path = "../../" }
diff --git a/contracts/exec-callee/exec-callee-dbg/Cargo.toml b/contracts/exec-callee/exec-callee-dbg/Cargo.toml
index b0295a2..a644a8e 100644
--- a/contracts/exec-callee/exec-callee-dbg/Cargo.toml
+++ b/contracts/exec-callee/exec-callee-dbg/Cargo.toml
@@ -5,8 +5,8 @@ edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 [dependencies]
-exec-callee = { path = "../", features = ["simulator"] }
-ckb-std = { path = "../../../", features = ["simulator"] }
+exec-callee = { path = "../", features = ["native-simulator"] }
+ckb-std = { path = "../../../", features = ["native-simulator"] }
 
 [lib]
 crate-type = ["cdylib"]
diff --git a/contracts/exec-callee/src/lib.rs b/contracts/exec-callee/src/lib.rs
index ba66e49..b5e1182 100644
--- a/contracts/exec-callee/src/lib.rs
+++ b/contracts/exec-callee/src/lib.rs
@@ -1,6 +1,6 @@
-#![cfg_attr(not(feature = "simulator"), no_std)]
+#![cfg_attr(not(feature = "native-simulator"), no_std)]
 
-#[cfg(feature = "simulator")]
+#[cfg(feature = "native-simulator")]
 pub mod entry;
-#[cfg(feature = "simulator")]
+#[cfg(feature = "native-simulator")]
 pub mod error;
diff --git a/src/debug.rs b/src/debug.rs
index 191e223..e15e0d8 100644
--- a/src/debug.rs
+++ b/src/debug.rs
@@ -29,7 +29,7 @@
 /// debug!("hello world");
 /// debug!("there is a universal error caused by {}", 42);
 /// ```
-#[cfg(not(feature = "simulator"))]
+#[cfg(not(feature = "native-simulator"))]
 #[macro_export]
 macro_rules! debug {
     ($fmt:literal) => {
@@ -42,7 +42,7 @@ macro_rules! debug {
     };
 }
 
-#[cfg(feature = "simulator")]
+#[cfg(feature = "native-simulator")]
 #[macro_export]
 macro_rules! debug {
 
diff --git a/src/entry.rs b/src/entry.rs
index 7a1cddc..9a0ab1e 100644
--- a/src/entry.rs
+++ b/src/entry.rs
@@ -59,7 +59,7 @@ macro_rules! entry {
     };
 }
 
-#[cfg(feature = "simulator")]
+#[cfg(feature = "native-simulator")]
 #[macro_export]
 macro_rules! entry_simulator {
     ($main:path) => {
@@ -71,7 +71,11 @@ macro_rules! entry_simulator {
             // Arg is the same as *const c_char ABI wise.
             argv: *const $crate::env::Arg,
         ) -> i8 {
-            let argv = core::slice::from_raw_parts(argv, argc as usize);
+            let argv = if argc == 0 {
+                &[]
+            } else {
+                core::slice::from_raw_parts(argv, argc as usize)
+            };
             $crate::env::set_argv(argv);
             $main()
         }
diff --git a/src/env.rs b/src/env.rs
index ad8565f..cebde4f 100644
--- a/src/env.rs
+++ b/src/env.rs
@@ -32,7 +32,7 @@ impl Deref for Arg {
     }
 }
 
-#[cfg(feature = "simulator")]
+#[cfg(feature = "native-simulator")]
 impl Arg {
     pub fn new(arg: &str) -> Self {
         Self {
@@ -53,7 +53,7 @@ pub fn argv() -> &'static [Arg] {
     unsafe { ARGV }
 }
 
-// For simulator and entry!.
+// For native-simulator and entry!.
 #[doc(hidden)]
 #[inline]
 pub unsafe fn set_argv(argv: &'static [Arg]) {
diff --git a/src/high_level.rs b/src/high_level.rs
index 1684250..6e2cad7 100644
--- a/src/high_level.rs
+++ b/src/high_level.rs
@@ -653,7 +653,7 @@ pub fn exec_cell(
     hash_type: ScriptHashType,
     argv: &[&CStr],
 ) -> Result<Infallible, SysError> {
-    #[cfg(not(feature = "simulator"))]
+    #[cfg(not(feature = "native-simulator"))]
     {
         let index = look_for_dep_with_hash2(code_hash, hash_type)?;
         let ret = syscalls::exec(index, Source::CellDep, 0, 0, argv);
@@ -664,7 +664,7 @@ pub fn exec_cell(
         };
         Err(err)
     }
-    #[cfg(feature = "simulator")]
+    #[cfg(feature = "native-simulator")]
     syscalls::exec_cell(code_hash, hash_type, argv)
 }
 
diff --git a/src/lib.rs b/src/lib.rs
index f656e62..20eb594 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -8,10 +8,9 @@
 //! * `entry!` macro: defines contract entry point
 //! * `default_alloc!` and `libc_alloc!` macro: defines global allocator for no-std rust
 
-#![cfg_attr(not(feature = "simulator"), no_std)]
+#![cfg_attr(not(feature = "native-simulator"), no_std)]
 #![cfg_attr(docsrs, feature(doc_auto_cfg))]
 
-#[cfg(not(feature = "rustc-dep-of-std"))]
 extern crate alloc;
 
 pub mod ckb_constants;
diff --git a/src/syscalls/mod.rs b/src/syscalls/mod.rs
index 1a05217..742e335 100644
--- a/src/syscalls/mod.rs
+++ b/src/syscalls/mod.rs
@@ -1,12 +1,12 @@
 // re-export to maintain compatible with old versions
 pub use crate::error::SysError;
 
-#[cfg(not(feature = "simulator"))]
+#[cfg(not(feature = "native-simulator"))]
 mod native;
-#[cfg(not(feature = "simulator"))]
+#[cfg(not(feature = "native-simulator"))]
 pub use native::*;
 
-#[cfg(feature = "simulator")]
+#[cfg(feature = "native-simulator")]
 mod simulator;
-#[cfg(feature = "simulator")]
+#[cfg(feature = "native-simulator")]
 pub use simulator::*;
diff --git a/src/syscalls/simulator.rs b/src/syscalls/simulator.rs
index 88ba05f..8312dd2 100644
--- a/src/syscalls/simulator.rs
+++ b/src/syscalls/simulator.rs
@@ -211,7 +211,7 @@ pub fn load_cell_code(
     _index: usize,
     _source: Source,
 ) -> Result<usize, SysError> {
-    panic!("This is not supported in the simulator!");
+    panic!("This is not supported in the native-simulator!");
 }
 
 pub fn vm_version() -> Result<u64, SysError> {
diff --git a/test/simulator/Cargo.toml b/test/simulator/Cargo.toml
index 3bcad82..b35fd86 100644
--- a/test/simulator/Cargo.toml
+++ b/test/simulator/Cargo.toml
@@ -16,7 +16,7 @@ name = "exec-callee"
 path = "src/exec_callee.rs"
 
 [dependencies]
-ckb-std = { path = "../..", features = ["ckb-types", "simulator"] }
+ckb-std = { path = "../..", features = ["ckb-types", "native-simulator"] }
 blake2b-ref = { version = "0.3", default-features = false }
 bytes = { version = "1.6.0", default-features = false }
 log = { version = "0.4.17", default-features = false }