Check number of allocations in refcount tests

compiler/test_gen/src/helpers/wasm.rs

@@ -303,28 +303,38 @@ where
 
     let memory = instance.exports.get_memory(MEMORY_NAME).unwrap();
 
+    let expected_len = num_refcounts as i32;
     let init_refcount_test = instance.exports.get_function("init_refcount_test").unwrap();
-    let init_result = init_refcount_test.call(&[wasmer::Value::I32(num_refcounts as i32)]);
-    let refcount_array_addr = match init_result {
+    let init_result = init_refcount_test.call(&[wasmer::Value::I32(expected_len)]);
+    let refcount_vector_addr = match init_result {
         Err(e) => return Err(format!("{:?}", e)),
         Ok(result) => match result[0] {
             wasmer::Value::I32(a) => a,
             _ => panic!(),
         },
     };
-    // An array of refcount pointers
-    let refcount_ptr_array: WasmPtr<WasmPtr<i32>, wasmer::Array> =
-        WasmPtr::new(refcount_array_addr as u32);
-    let refcount_ptrs: &[Cell<WasmPtr<i32>>] = refcount_ptr_array
-        .deref(memory, 0, num_refcounts as u32)
-        .unwrap();
 
+    // Run the test
     let test_wrapper = instance.exports.get_function(TEST_WRAPPER_NAME).unwrap();
     match test_wrapper.call(&[]) {
         Err(e) => return Err(format!("{:?}", e)),
         Ok(_) => {}
     }
 
+    // Check we got the right number of refcounts
+    let refcount_vector_len: WasmPtr<i32> = WasmPtr::new(refcount_vector_addr as u32);
+    let actual_len = refcount_vector_len.deref(memory).unwrap().get();
+    if actual_len != expected_len {
+        panic!("Expected {} refcounts but got {}", expected_len, actual_len);
+    }
+
+    // Read the actual refcount values
+    let refcount_ptr_array: WasmPtr<WasmPtr<i32>, wasmer::Array> =
+        WasmPtr::new(4 + refcount_vector_addr as u32);
+    let refcount_ptrs: &[Cell<WasmPtr<i32>>] = refcount_ptr_array
+        .deref(memory, 0, num_refcounts as u32)
+        .unwrap();
+
     let mut refcounts = Vec::with_capacity(num_refcounts);
     for i in 0..num_refcounts {
         let rc_ptr = refcount_ptrs[i].get();

compiler/test_gen/src/helpers/wasm_test_platform.c

@@ -3,21 +3,26 @@
 // Makes test runs take 50% longer, due to linking
 #define ENABLE_PRINTF 0
 
+typedef struct {
+    size_t length;
+    size_t* elements[]; // flexible array member
+} Vector;
+
 // Globals for refcount testing
-size_t **rc_pointers; // array of pointers to refcount values
-size_t rc_pointers_len;
-size_t rc_pointers_index;
+Vector *rc_pointers;
+size_t rc_pointers_capacity;
 
 // The rust test passes us the max number of allocations it expects to make,
 // and we tell it where we're going to write the refcount pointers.
 // It won't actually read that memory until later, when the test is done.
-size_t **init_refcount_test(size_t max_allocs)
+Vector *init_refcount_test(size_t capacity)
 {
-    rc_pointers = malloc(max_allocs * sizeof(size_t *));
-    rc_pointers_len = max_allocs;
-    rc_pointers_index = 0;
-    for (size_t i = 0; i < max_allocs; ++i)
-        rc_pointers[i] = NULL;
+    rc_pointers_capacity = capacity;
+
+    rc_pointers = malloc((1 + capacity) * sizeof(size_t *));
+    rc_pointers->length = 0;
+    for (size_t i = 0; i < capacity; ++i)
+        rc_pointers->elements[i] = NULL;
 
     return rc_pointers;
 }
@@ -51,11 +56,11 @@ void *roc_alloc(size_t size, unsigned int alignment)
     if (rc_pointers)
     {
         ASSERT(alignment >= sizeof(size_t));
-        ASSERT(rc_pointers_index < rc_pointers_len);
+        ASSERT(rc_pointers->length < rc_pointers_capacity);
 
         size_t *rc_ptr = alloc_ptr_to_rc_ptr(allocated, alignment);
-        rc_pointers[rc_pointers_index] = rc_ptr;
-        rc_pointers_index++;
+        rc_pointers->elements[rc_pointers->length] = rc_ptr;
+        rc_pointers->length++;
     }
 
 #if ENABLE_PRINTF
@@ -94,15 +99,15 @@ void roc_dealloc(void *ptr, unsigned int alignment)
         // Then even if malloc reuses the space, everything still works
         size_t *rc_ptr = alloc_ptr_to_rc_ptr(ptr, alignment);
         int i = 0;
-        for (; i < rc_pointers_index; ++i)
+        for (; i < rc_pointers->length; ++i)
         {
-            if (rc_pointers[i] == rc_ptr)
+            if (rc_pointers->elements[i] == rc_ptr)
             {
-                rc_pointers[i] = NULL;
+                rc_pointers->elements[i] = NULL;
                 break;
             }
         }
-        int was_found = i < rc_pointers_index;
+        int was_found = i < rc_pointers->length;
         ASSERT(was_found);
     }