From: Mark Thom <markjordanthom@gmail.com>
Date: Tue, 21 Jan 2020 03:59:30 +0000 (-0700)
Subject: don't hold on to popped or frames
X-Git-Tag: v0.8.118~23
X-Git-Url: https://git.sagredo.dev/?a=commitdiff_plain;h=40bf5bc75fc4124b4d6d0e373aabc0220a53e9ce;p=scryer-prolog.git

don't hold on to popped or frames
---

diff --git a/src/prolog/machine/machine_state.rs b/src/prolog/machine/machine_state.rs
index 134b2924..05749105 100644
--- a/src/prolog/machine/machine_state.rs
+++ b/src/prolog/machine/machine_state.rs
@@ -552,7 +552,7 @@ pub(crate) trait CallPolicy: Any {
             attr_var_init_queue_b,
             attr_var_init_bindings_b);
 
-        machine_st.truncate_stack();
+        machine_st.stack.truncate(machine_st.b);
         machine_st.b = machine_st.stack.index_or_frame(b).prelude.b;
 
         machine_st.hb = machine_st.heap.h;
@@ -600,7 +600,7 @@ pub(crate) trait CallPolicy: Any {
             attr_var_init_bindings_b,
         );
 
-        machine_st.truncate_stack();
+        machine_st.stack.truncate(machine_st.b);
         machine_st.b = machine_st.stack.index_or_frame(b).prelude.b;
 
         machine_st.hb = machine_st.heap.h;
diff --git a/src/prolog/machine/machine_state_impl.rs b/src/prolog/machine/machine_state_impl.rs
index 11894901..57aeab5d 100644
--- a/src/prolog/machine/machine_state_impl.rs
+++ b/src/prolog/machine/machine_state_impl.rs
@@ -2077,12 +2077,6 @@ impl MachineState {
         self.fail = true;
     }
 
-    pub(super) fn truncate_stack(&mut self) {
-        if self.b > self.e {
-            self.stack.truncate_to_frame(self.b);
-        }
-    }
-
     pub(crate) fn is_cyclic_term(&self, addr: Addr) -> bool {
         let mut seen = IndexSet::new();
         let mut fail = false;
diff --git a/src/prolog/machine/stack.rs b/src/prolog/machine/stack.rs
index 2de3582d..a9551756 100644
--- a/src/prolog/machine/stack.rs
+++ b/src/prolog/machine/stack.rs
@@ -321,18 +321,15 @@ impl Stack {
         }
     }
 
-    pub fn truncate_to_frame(&mut self, b: usize) {
+    pub fn truncate(&mut self, b: usize) {
         if b == 0 {
-            self.truncate(mem::align_of::<Addr>());
+            self.inner_truncate(mem::align_of::<Addr>());
         } else {
-            let univ_prelude = self.index_or_frame(b).prelude.univ_prelude;
-            let size = OrFrame::size_of(univ_prelude.num_cells);
-
-            self.truncate(b + size);
+            self.inner_truncate(b);
         }
     }
 
-    fn truncate(&mut self, b: usize) {
+    fn inner_truncate(&mut self, b: usize) {
         let mut b = b + self.base as usize;
         let base =  b;