From dc89ed57f216549a20b5cb5134c51a0a65517254 Mon Sep 17 00:00:00 2001
From: Mark Thom <markjordanthom@gmail.com>
Date: Sun, 24 Feb 2019 13:40:58 -0700
Subject: [PATCH] evacuate when allocating anon vars

---
 src/prolog/allocator.rs        | 2 +-
 src/prolog/codegen.rs          | 4 ++--
 src/prolog/compile.rs          | 2 +-
 src/prolog/debray_allocator.rs | 9 +++++++--
 src/prolog/lib/between.pl      | 2 +-
 src/prolog/machine/mod.rs      | 6 +++---
 6 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/src/prolog/allocator.rs b/src/prolog/allocator.rs
index a6c74dd5..a498fbaf 100644
--- a/src/prolog/allocator.rs
+++ b/src/prolog/allocator.rs
@@ -11,7 +11,7 @@ pub trait Allocator<'a>
 {
     fn new() -> Self;
 
-    fn mark_anon_var<Target>(&mut self, Level, &mut Vec<Target>)
+    fn mark_anon_var<Target>(&mut self, Level, GenContext, &mut Vec<Target>)
         where Target: CompilationTarget<'a>;
     fn mark_non_var<Target>(&mut self, Level, GenContext, &'a Cell<RegType>, &mut Vec<Target>)
         where Target: CompilationTarget<'a>;
diff --git a/src/prolog/codegen.rs b/src/prolog/codegen.rs
index 80ae6824..ca4a81ac 100644
--- a/src/prolog/codegen.rs
+++ b/src/prolog/codegen.rs
@@ -158,7 +158,7 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<TermMarker>
     {
         match subterm {
             &Term::AnonVar if is_exposed =>
-                self.marker.mark_anon_var(Level::Deep, target),
+                self.marker.mark_anon_var(Level::Deep, term_loc, target),
             &Term::AnonVar =>
                 Self::add_or_increment_void_instr(target),
             &Term::Cons(ref cell, _, _) | &Term::Clause(ref cell, _, _, _) => {
@@ -207,7 +207,7 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<TermMarker>
                     if let GenContext::Head = term_loc {
                         self.marker.advance_arg();
                     } else {
-                        self.marker.mark_anon_var(lvl, &mut target);
+                        self.marker.mark_anon_var(lvl, term_loc, &mut target);
                     },
                 TermRef::Var(lvl @ Level::Shallow, cell, ref var) if var.as_str() == "!" => {
                     if self.marker.is_unbound(var.clone()) {
diff --git a/src/prolog/compile.rs b/src/prolog/compile.rs
index 041ee425..f318bb39 100644
--- a/src/prolog/compile.rs
+++ b/src/prolog/compile.rs
@@ -257,7 +257,7 @@ impl ListingCompiler {
 
             let idx = code_dir.entry((name.clone(), arity)).or_insert(CodeIndex::default());
             set_code_index!(idx, IndexPtr::Index(p), self.get_module_name());
-
+            
             code.extend(decl_code.into_iter());
         }
 
diff --git a/src/prolog/debray_allocator.rs b/src/prolog/debray_allocator.rs
index adfefc73..86053c48 100644
--- a/src/prolog/debray_allocator.rs
+++ b/src/prolog/debray_allocator.rs
@@ -211,7 +211,7 @@ impl<'a> Allocator<'a> for DebrayAllocator
         }
     }
 
-    fn mark_anon_var<Target>(&mut self, lvl: Level, target: &mut Vec<Target>)
+    fn mark_anon_var<Target>(&mut self, lvl: Level, term_loc: GenContext, target: &mut Vec<Target>)
         where Target: CompilationTarget<'a>
     {
         let r = RegType::Temp(self.alloc_reg_to_non_var());
@@ -220,8 +220,13 @@ impl<'a> Allocator<'a> for DebrayAllocator
             Level::Deep => target.push(Target::subterm_to_variable(r)),
             Level::Root | Level::Shallow => {
                 let k = self.arg_c;
-                self.arg_c += 1;
 
+                if let GenContext::Last(chunk_num) = term_loc {
+                    self.evacuate_arg(chunk_num, target);
+                }
+
+                self.arg_c += 1;
+                
                 target.push(Target::argument_to_variable(r, k));
             }
         };
diff --git a/src/prolog/lib/between.pl b/src/prolog/lib/between.pl
index b54a4f04..78aaf26f 100644
--- a/src/prolog/lib/between.pl
+++ b/src/prolog/lib/between.pl
@@ -84,7 +84,7 @@ diag_ints(M, N, M0, N0) :-
     diag_nats_signs(M, N, M0, N0).
 
 diag_ints(M, N) :-
-    diag_ints(M0, N0, M, N).
+    diag_ints(_, _, M, N).
 
 gen_ints(L, U) :-
     can_be(integer, L), can_be(integer, U),
diff --git a/src/prolog/machine/mod.rs b/src/prolog/machine/mod.rs
index c2567c4e..b7446415 100644
--- a/src/prolog/machine/mod.rs
+++ b/src/prolog/machine/mod.rs
@@ -343,7 +343,7 @@ impl Machine {
     }
 
     fn compile_libraries(&mut self) {
-        compile_user_module(self, LISTS.as_bytes());        
+        compile_user_module(self, LISTS.as_bytes());
         compile_user_module(self, QUEUES.as_bytes());
         compile_user_module(self, ERROR.as_bytes());
         compile_user_module(self, BETWEEN.as_bytes());
@@ -506,7 +506,7 @@ impl Machine {
         for (var, addr) in sorted_vars {
             output = self.machine_st.print_var_eq(var.clone(), addr.clone(), var_dir, output);
         }
-        
+
         output
     }
 
@@ -608,7 +608,7 @@ impl MachineState {
                 _ => {}
             };
         }
-    }    
+    }
 
     fn record_var_places(&self, chunk_num: usize, alloc_locs: &AllocVarDict,
                          heap_locs: &mut HeapVarDict)
-- 
2.54.0