From d6b6eda77d5d31ec0564d05434c14bb9ab37c7c4 Mon Sep 17 00:00:00 2001
From: Mark Thom <markjordanthom@gmail.com>
Date: Mon, 28 Apr 2025 23:39:52 -0700
Subject: [PATCH] fix cont function crashes (#2920)

---
 src/machine/compile.rs       |  4 ----
 src/machine/machine_state.rs | 18 ------------------
 src/machine/system_calls.rs  | 17 +++++++++++------
 3 files changed, 11 insertions(+), 28 deletions(-)

diff --git a/src/machine/compile.rs b/src/machine/compile.rs
index 4f0fb1b6..1b2f6bff 100644
--- a/src/machine/compile.rs
+++ b/src/machine/compile.rs
@@ -1261,10 +1261,6 @@ impl<'a, LS: LoadState<'a>> Loader<'a, LS> {
         let code_len = self.wam_prelude.code.len();
         let mut code_ptr = code_len;
 
-        if key == (atom!("..."), 2) {
-            print!("");
-        }
-
         let mut clauses = vec![];
         let mut preprocessor = Preprocessor::new(settings);
 
diff --git a/src/machine/machine_state.rs b/src/machine/machine_state.rs
index 7c8f1abe..941d9f4d 100644
--- a/src/machine/machine_state.rs
+++ b/src/machine/machine_state.rs
@@ -186,26 +186,8 @@ impl IndexMut<RegType> for MachineState {
 
 pub type CallResult = Result<(), Vec<FunctorElement>>;
 
-/*
-#[inline(always)]
-pub fn pstr_loc_and_offset(heap: &[HeapCellValue], index: usize) -> (usize, Fixnum) {
-    read_heap_cell!(heap[index],
-        (HeapCellValueTag::PStr | HeapCellValueTag::CStr) => {
-            (index, Fixnum::build_with(0))
-        }
-        (HeapCellValueTag::PStrOffset, h) => {
-            (h, cell_as_fixnum!(heap[index+1]))
-        }
-        _ => {
-            unreachable!()
-        }
-    )
-}
-*/
-
 // size may be an upper bound.
 // true_size is calculated to compute the exact offset.
-
 fn push_var_eq_functors<'a>(
     heap: &mut Heap,
     size: usize,
diff --git a/src/machine/system_calls.rs b/src/machine/system_calls.rs
index d47b36e9..6875edfb 100644
--- a/src/machine/system_calls.rs
+++ b/src/machine/system_calls.rs
@@ -5711,7 +5711,6 @@ impl Machine {
 
                 if addr.get_tag() == HeapCellValueTag::StackVar {
                     section.push_cell(heap_loc_as_cell!(h + 1 + idx));
-
                     self.machine_st.stack[stack_offset] = heap_loc_as_cell!(h + 1 + idx);
 
                     // have to inline the TrailRef::Ref(RefTag::StackCell) case of MachineState::trail
@@ -5730,7 +5729,7 @@ impl Machine {
             }
         });
 
-        let chunk = str_loc_as_cell!(self.machine_st.heap.cell_len());
+        let chunk = str_loc_as_cell!(h);
         unify!(self.machine_st, self.machine_st.registers[3], chunk);
     }
 
@@ -6317,13 +6316,13 @@ impl Machine {
             let e = and_frame.prelude.e;
             let e = Fixnum::build_with(i64::try_from(e).unwrap());
 
-            let mut writer = Heap::functor_writer(functor!(atom!("dir_entry"), [fixnum(cp)]));
-
-            let p_functor_cell = step_or_resource_error!(machine_st, writer(&mut machine_st.heap));
-
             machine_st.unify_fixnum(e, machine_st.registers[2]);
 
             if !machine_st.fail {
+                let mut writer = Heap::functor_writer(functor!(atom!("dir_entry"), [fixnum(cp)]));
+                let p_functor_cell =
+                    step_or_resource_error!(machine_st, writer(&mut machine_st.heap));
+
                 unify!(machine_st, p_functor_cell, machine_st.registers[3]);
             }
         };
@@ -6350,6 +6349,12 @@ impl Machine {
                 // active permanent variables can be read from
                 // it later.
                 let and_frame = self.machine_st.stack.index_and_frame(e);
+
+                if and_frame.prelude.cp == 0 {
+                    self.machine_st.fail = true;
+                    return;
+                }
+
                 let cp = and_frame.prelude.cp - 1;
                 let mut writer = Heap::functor_writer(functor!(atom!("dir_entry"), [fixnum(cp)]));
 
-- 
2.54.0