cgen: add support for shared arrays (#5721)

vlib/v/gen/cgen.v

@@ -2376,10 +2376,17 @@ fn (mut g Gen) index_expr(node ast.IndexExpr) {
 				if g.is_assign_lhs && !is_selector && node.is_setter {
 					g.is_array_set = true
 					g.write('array_set(')
-					if !left_is_ptr {
+					if !left_is_ptr || node.left_type.has_flag(.shared_f) {
 						g.write('&')
 					}
 					g.expr(node.left)
+					if node.left_type.has_flag(.shared_f) {
+						if left_is_ptr {
+							g.write('->val')
+						} else {
+							g.write('.val')
+						}
+					}
 					g.write(', ')
 					g.expr(node.index)
 					mut need_wrapper := true
@@ -2404,10 +2411,17 @@ fn (mut g Gen) index_expr(node ast.IndexExpr) {
 						info.elem_type != table.string_type {
 						// TODO move this
 						g.write('*($elem_type_str*)array_get(')
-						if left_is_ptr {
+						if left_is_ptr && !node.left_type.has_flag(.shared_f) {
 							g.write('*')
 						}
 						g.expr(node.left)
+						if node.left_type.has_flag(.shared_f) {
+							if left_is_ptr {
+								g.write('->val')
+							} else {
+								g.write('.val')
+							}
+						}
 						g.write(', ')
 						g.expr(node.index)
 						g.write(') ')
@@ -2428,10 +2442,17 @@ fn (mut g Gen) index_expr(node ast.IndexExpr) {
 					}
 				} else {
 					g.write('(*($elem_type_str*)array_get(')
-					if left_is_ptr {
+					if left_is_ptr && !node.left_type.has_flag(.shared_f) {
 						g.write('*')
 					}
 					g.expr(node.left)
+					if node.left_type.has_flag(.shared_f) {
+						if left_is_ptr {
+							g.write('->val')
+						} else {
+							g.write('.val')
+						}
+					}
 					g.write(', ')
 					g.expr(node.index)
 					g.write('))')
@@ -4497,6 +4518,24 @@ _Interface* I_${cctype}_to_Interface_${interface_name}_ptr($cctype* x) {
 
 fn (mut g Gen) array_init(it ast.ArrayInit) {
 	type_sym := g.table.get_type_symbol(it.typ)
+	styp := g.typ(it.typ)
+	mut shared_styp := '' // only needed for shared &[]{...}
+	is_amp := g.is_amp
+	g.is_amp = false
+	if is_amp {
+		g.out.go_back(1) // delete the `&` already generated in `prefix_expr()
+		if g.is_shared {
+			mut shared_typ := it.typ.set_flag(.shared_f)
+			shared_styp = g.typ(shared_typ)
+			g.writeln('($shared_styp*)memdup(&($shared_styp){.val = ')
+		} else {
+			g.write('($styp*)memdup(&') // TODO: doesn't work with every compiler
+		}
+	} else {
+		if g.is_shared {
+			g.writeln('{.val = ($styp*)')
+		}
+	}
 	if type_sym.kind == .array_fixed {
 		g.write('{')
 		for i, expr in it.exprs {
@@ -4568,6 +4607,14 @@ fn (mut g Gen) array_init(it ast.ArrayInit) {
 		}
 	}
 	g.write('}))')
+	if g.is_shared {
+		g.write(', .mtx = sync__new_rwmutex()}')
+		if is_amp {
+			g.write(', sizeof($shared_styp))')
+		}
+	} else if is_amp {
+		g.write(', sizeof($styp))')
+	}
 }
 
 // `ui.foo(button)` =>

vlib/v/tests/shared_array_test.v

@@ -0,0 +1,41 @@
+import sync
+import time
+
+fn incr(shared foo []int, index int) {
+	for _ in 0 .. 100000 {
+		lock foo {
+			foo[index] = foo[index] + 1
+		}
+	}
+	lock foo {
+		foo[2]++
+	}
+}
+
+fn test_shared_array() {
+	shared foo := &[10, 20, 0]
+	go incr(shared foo, 0)
+	go incr(shared foo, 1)
+	go incr(shared foo, 0)
+	go incr(shared foo, 1)
+	for _ in 0 .. 50000 {
+		lock foo {
+			foo[0] -= 2
+			foo[1] += 3
+		}
+	}
+	mut finished_threads := 0
+	for {
+		rlock foo {
+			finished_threads = foo[2]
+		}
+		if finished_threads == 4 {
+			break
+		}
+		time.sleep_ms(100)
+	}
+	rlock foo {
+		assert foo[0] == 100010
+		assert foo[1] == 350020
+	}
+}

vlib/v/tests/shared_lock_2_test.v

@@ -38,8 +38,8 @@ fn test_shared_receiver_lock() {
 		}
 	}
 	// the following would be a good application for a channel
-	for finished := false; ; {
-		lock z {
+	for finished := false; true; {
+		rlock z {
 			finished = z.a == 0
 		}
 		if finished {
@@ -47,7 +47,7 @@ fn test_shared_receiver_lock() {
 		}
 		time.sleep_ms(100)
 	}
-	lock x, y {
+	rlock x, y {
 		assert x.a == 7 && y.a == 5
 	}
 }

vlib/v/tests/shared_lock_3_test.v

@@ -44,9 +44,9 @@ fn test_shared_lock() {
 		time.sleep_ms(20)
 	}
 	// wait until all read threads are finished
-	for finished := false; ; {
+	for finished := false; true; {
 		mut rr := 0
-		lock z {
+		rlock z {
 			rr = z.a
 			finished = z.a == 0
 		}

vlib/v/tests/shared_lock_4_test.v

@@ -44,9 +44,9 @@ fn test_shared_lock() {
 		time.sleep_ms(20)
 	}
 	// wait until all read threads are finished
-	for finished := false; ; {
+	for finished := false; true; {
 		mut rr := 0
-		lock z {
+		rlock z {
 			rr = z.a
 			finished = z.a == 0
 		}

vlib/v/tests/shared_lock_test.v

@@ -38,8 +38,8 @@ fn test_shared_lock() {
 		}
 	}
 	// the following would be a good application for a channel
-	for finished := false; ; {
-		lock z {
+	for finished := false; true; {
+		rlock z {
 			finished = z.a == 0
 		}
 		if finished {
@@ -47,7 +47,7 @@ fn test_shared_lock() {
 		}
 		time.sleep_ms(100)
 	}
-	lock x, y {
+	rlock x, y {
 		assert x.a == 7 && y.a == 5
 	}
 }