Binding-side changes required to support pinning profiler (#247)

Follow-up to mmtk/julia#88, with binding-side
changes required to support the pinning profiler.

Author: d-netto

mmtk/api/mmtk.h

@@ -42,13 +42,15 @@ extern void* mmtk_alloc_large(MMTk_Mutator mutator, size_t size,
 extern void mmtk_post_alloc(MMTk_Mutator mutator, void* refer,
     size_t bytes, int allocator);
 
+extern bool mmtk_is_reachable_object(void* ref);
 extern bool mmtk_is_live_object(void* ref);
 extern bool mmtk_is_mapped_object(void* ref);
 extern bool mmtk_is_mapped_address(void* addr);
 extern int mmtk_object_is_managed_by_mmtk(void* addr);
 extern void mmtk_runtime_panic(void);
 extern void mmtk_unreachable(void);
 extern unsigned char mmtk_pin_object(void* obj);
+extern unsigned char mmtk_unpin_object(void* obj);
 extern bool mmtk_is_object_pinned(void* obj);
 extern unsigned char mmtk_pin_pointer(void* ptr);
 extern bool mmtk_is_pointer_pinned(void* ptr);

mmtk/src/api.rs

@@ -250,6 +250,11 @@ pub extern "C" fn mmtk_total_bytes() -> usize {
     memory_manager::total_bytes(&SINGLETON)
 }
 
+#[no_mangle]
+pub extern "C" fn mmtk_is_reachable_object(object: ObjectReference) -> bool {
+    object.is_reachable()
+}
+
 #[no_mangle]
 pub extern "C" fn mmtk_is_live_object(object: ObjectReference) -> bool {
     object.is_live()

mmtk/src/collection.rs

@@ -4,6 +4,7 @@ use crate::{
     jl_hrtime, jl_throw_out_of_memory_error,
 };
 use crate::{JuliaVM, USER_TRIGGERED_GC};
+use crate::jl_gc_log;
 use log::{debug, trace};
 use mmtk::util::alloc::AllocationError;
 use mmtk::util::heap::GCTriggerPolicy;
@@ -84,6 +85,9 @@ impl Collection<JuliaVM> for VMCollection {
     }
 
     fn resume_mutators(_tls: VMWorkerThread) {
+        unsafe {
+            jl_gc_log(); // Remove dead objects form pinning log
+        }
         // unpin conservative roots
         crate::conservative::unpin_conservative_roots();
 

mmtk/src/conservative.rs

@@ -1,4 +1,5 @@
 use crate::julia_types::*;
+use crate::jl_log_pinning_event;
 use mmtk::memory_manager;
 use mmtk::util::constants::BYTES_IN_ADDRESS;
 use mmtk::util::{Address, ObjectReference};
@@ -13,7 +14,13 @@ pub fn pin_conservative_roots() {
 
     let mut roots = CONSERVATIVE_ROOTS.lock().unwrap();
     let n_roots = roots.len();
-    roots.retain(|obj| mmtk::memory_manager::pin_object(*obj));
+    roots.retain(|obj| {
+        unsafe {
+            let obj = (*obj).to_raw_address();
+            jl_log_pinning_event(obj, std::ptr::null_mut(), 0);
+        }
+        mmtk::memory_manager::pin_object(*obj)
+    });
     let n_pinned = roots.len();
     log::debug!("Conservative roots: {}, pinned: {}", n_roots, n_pinned);
 }

mmtk/src/lib.rs

@@ -131,6 +131,8 @@ extern "C" {
         total_start: *mut Address,
         total_end: *mut Address,
     );
+    pub fn jl_log_pinning_event(pinned_object: Address, filename: *const i8, lineno: i32);
+    pub fn jl_gc_log();
     pub static jl_true: *mut crate::julia_types::jl_value_t;
 }