runtime: replace null fillers with free_word

dinfuehr · Dec 28, 2023 · 00c1593 · 00c1593
1 parent 1a23346
commit 00c1593
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Showing 5 changed files with 5 additions and 23 deletions.
diff --git a/dora-runtime/src/gc.rs b/dora-runtime/src/gc.rs
@@ -543,7 +543,7 @@ pub fn fill_region_with(vm: &VM, start: Address, end: Address, clear: bool) {
         // nothing to do
     } else if end.offset_from(start) == mem::ptr_width_usize() {
         unsafe {
-            *start.to_mut_ptr::<usize>() = 0;
+            *start.to_mut_ptr::<usize>() = vm.known.free_word_class_address().to_usize();
         }
     } else if end.offset_from(start) == Header::size() as usize {
         // fill with object

diff --git a/dora-runtime/src/gc/swiper.rs b/dora-runtime/src/gc/swiper.rs
@@ -616,12 +616,7 @@ where
         let object = scan.to_obj();
 
         if object.is_filler(vm) {
-            let size = if object.header().raw_vtblptr().is_null() {
-                mem::ptr_width_usize()
-            } else {
-                object.size()
-            };
-            scan = scan.offset(size);
+            scan = scan.offset(object.size());
         } else {
             let object_size = object.size();
             fct(object, scan, object_size);

diff --git a/dora-runtime/src/gc/swiper/minor.rs b/dora-runtime/src/gc/swiper/minor.rs
@@ -19,7 +19,6 @@ use crate::gc::{
     fill_region, fill_region_with, iterate_weak_roots, Address, GcReason, GenerationAllocator,
     Region,
 };
-use crate::mem;
 use crate::object::{ForwardResult, Obj, VtblptrWordKind};
 use crate::threads::DoraThread;
 use crate::timer::Timer;
@@ -613,13 +612,7 @@ impl<'a> CopyTask<'a> {
             let object = ptr.to_obj();
 
             if object.is_filler(self.vm) {
-                let size = if object.header().raw_vtblptr().is_null() {
-                    mem::ptr_width_usize()
-                } else {
-                    object.size()
-                };
-
-                ptr = ptr.offset(size);
+                ptr = ptr.offset(object.size());
             } else {
                 object.visit_reference_fields(|field| {
                     let field_ptr = field.get();

diff --git a/dora-runtime/src/gc/swiper/verify.rs b/dora-runtime/src/gc/swiper/verify.rs
@@ -187,16 +187,11 @@ impl<'a> Verifier<'a> {
 
         while curr < region.end {
             let object = curr.to_obj();
-            let vtblptr = object.header().raw_vtblptr();
 
             if object.is_filler(self.vm) {
                 assert!(!self.in_large, "large object space should not have fillers");
 
-                let size = if vtblptr.is_null() {
-                    mem::ptr_width_usize()
-                } else {
-                    object.size()
-                };
+                let size = object.size();
                 let object_end = curr.offset(size);
 
                 if self.in_old && on_different_cards(curr, object_end) {

diff --git a/dora-runtime/src/object.rs b/dora-runtime/src/object.rs
@@ -307,8 +307,7 @@ impl Obj {
     pub fn is_filler(&self, vm: &VM) -> bool {
         let vtblptr = self.header().raw_vtblptr();
 
-        vtblptr.is_null()
-            || vtblptr == vm.known.free_word_class_address()
+        vtblptr == vm.known.free_word_class_address()
             || vtblptr == vm.known.free_array_class_address()
             || vtblptr == vm.known.free_object_class_address()
     }