Changeset e8b8e65

Timestamp:

Oct 31, 2022, 4:39:28 PM (2 years ago)

Author:

Thierry Delisle <tdelisle@…>

Branches:

ADT, ast-experimental, master

Children:

1dafdfc

Parents:

7f3b5ce

Message:

Added implementation of call_once

Files:

• libcfa/src/Makefile.am (modified) (1 diff)
• libcfa/src/concurrency/once.hfa (added)
• libcfa/src/containers/lockfree.hfa (modified) (5 diffs)
• tests/concurrent/.expect/once.txt (added)
• tests/concurrent/once.cfa (added)

libcfa/src/Makefile.am

@@ -111 +111 @@
         concurrency/invoke.h \
         concurrency/future.hfa \
+        concurrency/once.hfa \
         concurrency/kernel/fwd.hfa \
         concurrency/mutex_stmt.hfa

libcfa/src/containers/lockfree.hfa

@@ -142 +142 @@
 
         static inline void ?{}(poison_list(T) & this) { this.head = 0p; }
+        static inline bool is_poisoned( const poison_list(T) & this ) { return 1p == this.head; }
 
         static inline forall(| { T * volatile & ?`next ( T * ); })
@@ -147 +148 @@
                 // Adds an element to the list
                 // Multi-Thread Safe, Lock-Free
-                T * push(poison_list(T) & this, T * elem) __attribute__((artificial));
-                T * push(poison_list(T) & this, T * elem) {
+                bool push(poison_list(T) & this, T * elem) __attribute__((artificial));
+                bool push(poison_list(T) & this, T * elem) {
                         /* paranoid */ verify(0p == (elem`next));
                         __atomic_store_n( &elem`next, (T*)1p, __ATOMIC_RELAXED );
@@ -156 +157 @@
                         for() {
                                 // check if it's poisoned
-                                if(expected == 1p) return 0p;
+                                if(expected == 1p) return false;
 
                                 // try to CAS the elem in
@@ -162 +163 @@
                                         // We managed to exchange in, we are done
 
-                                        // We should never succeed the CAS if it's poisonned.
-                                        /* paranoid */ verify( expected != 1p );
+                                        // We should never succeed the CAS if it's poisonned and the elem should be 1p.
+                                        /* paranoid */ verify( expected  != 1p );
+                                        /* paranoid */ verify( elem`next == 1p );
 
                                         // If we aren't the first, we need to tell the person before us
                                         // No need to
                                         elem`next = expected;
-                                        return expected;
+                                        return true;
                                 }
                         }
@@ -190 +192 @@
                 T * poison(poison_list(T) & this) {
                         T * ret = __atomic_exchange_n( &this.head, (T*)1p, __ATOMIC_SEQ_CST );
-                        /* paranoid */ verify( ret != (T*)1p );
+                        /* paranoid */ verifyf( ret != (T*)1p, "Poison list %p poisoned more than once!", &this );
                         return ret;
                 }