diff --git a/src/fn_call.rs b/src/fn_call.rs
index d11364ce0d1..ab82223f234 100644
--- a/src/fn_call.rs
+++ b/src/fn_call.rs
@@ -513,10 +513,6 @@ pub trait EvalContextExt<'a, 'mir, 'tcx: 'a+'mir>: crate::MiriEvalContextExt<'a,
                 this.write_null(dest)?;
             }
 
-            "_tlv_atexit" => {
-                // FIXME: Register the dtor
-            },
-
             // Determining stack base address
             "pthread_attr_init" | "pthread_attr_destroy" | "pthread_attr_get_np" |
             "pthread_getattr_np" | "pthread_self" | "pthread_get_stacksize_np" => {
@@ -554,7 +550,18 @@ pub trait EvalContextExt<'a, 'mir, 'tcx: 'a+'mir>: crate::MiriEvalContextExt<'a,
                 this.write_null(dest)?;
             }
 
-            // Windows API subs
+            // macOS API stubs
+            "_tlv_atexit" => {
+                // FIXME: Register the dtor
+            },
+            "_NSGetArgc" => {
+                this.write_scalar(Scalar::Ptr(this.machine.argc.unwrap()), dest)?;
+            },
+            "_NSGetArgv" => {
+                this.write_scalar(Scalar::Ptr(this.machine.argv.unwrap()), dest)?;
+            },
+
+            // Windows API stubs
             "AddVectoredExceptionHandler" => {
                 // any non zero value works for the stdlib. This is just used for stackoverflows anyway
                 this.write_scalar(Scalar::from_int(1, dest.layout.size), dest)?;
@@ -576,8 +583,6 @@ pub trait EvalContextExt<'a, 'mir, 'tcx: 'a+'mir>: crate::MiriEvalContextExt<'a,
                 // this is c::ERROR_CALL_NOT_IMPLEMENTED
                 this.write_scalar(Scalar::from_int(120, dest.layout.size), dest)?;
             },
-
-            // Windows TLS
             "TlsAlloc" => {
                 // This just creates a key; Windows does not natively support TLS dtors.
 
diff --git a/src/lib.rs b/src/lib.rs
index 28639976aa0..e6e1a338c9d 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -121,7 +121,11 @@ pub fn create_ecx<'a, 'mir: 'a, 'tcx: 'mir>(
 
     // Second argument (argc): 1
     let dest = ecx.eval_place(&mir::Place::Local(args.next().unwrap()))?;
-    ecx.write_scalar(Scalar::from_int(1, dest.layout.size), dest)?;
+    let argc = Scalar::from_int(1, dest.layout.size);
+    ecx.write_scalar(argc, dest)?;
+    let argc_place = ecx.allocate(dest.layout, MiriMemoryKind::Env.into())?;
+    ecx.write_scalar(argc, argc_place.into())?;
+    ecx.machine.argc = Some(argc_place.ptr.to_ptr()?);
 
     // FIXME: extract main source file path
     // Third argument (argv): &[b"foo"]
@@ -132,7 +136,11 @@ pub fn create_ecx<'a, 'mir: 'a, 'tcx: 'mir>(
     let foo_place = ecx.allocate(foo_layout, MiriMemoryKind::Env.into())?;
     ecx.write_scalar(Scalar::Ptr(foo), foo_place.into())?;
     ecx.memory_mut().mark_immutable(foo_place.to_ptr()?.alloc_id)?;
-    ecx.write_scalar(foo_place.ptr, dest)?;
+    let argv = foo_place.ptr;
+    ecx.write_scalar(argv, dest)?;
+    let argv_place = ecx.allocate(dest.layout, MiriMemoryKind::Env.into())?;
+    ecx.write_scalar(argv, argv_place.into())?;
+    ecx.machine.argc = Some(argv_place.ptr.to_ptr()?);
 
     assert!(args.next().is_none(), "start lang item has more arguments than expected");
 
@@ -253,6 +261,11 @@ pub struct Evaluator<'tcx> {
     /// Miri does not expose env vars from the host to the emulated program
     pub(crate) env_vars: HashMap<Vec<u8>, Pointer<Borrow>>,
 
+    /// Program arguments (`Option` because we can only initialize them after creating the ecx).
+    /// These are *pointers* to argc/argv because macOS.
+    pub(crate) argc: Option<Pointer<Borrow>>,
+    pub(crate) argv: Option<Pointer<Borrow>>,
+
     /// TLS state
     pub(crate) tls: TlsData<'tcx>,
 
@@ -267,6 +280,8 @@ impl<'tcx> Evaluator<'tcx> {
     fn new(validate: bool) -> Self {
         Evaluator {
             env_vars: HashMap::default(),
+            argc: None,
+            argv: None,
             tls: TlsData::default(),
             validate,
             stacked_borrows: stacked_borrows::State::default(),