autofree: handle more statements

vlib/builtin/string_test.v

@@ -241,6 +241,8 @@ two ',
 four!']
 	s = strings.join(' ')
 	assert s.contains('one') && s.contains('two ') && s.contains('four')
+	empty :=  []string{len:0}
+	assert empty.join('A') == ''
 }
 
 fn test_clone() {
@@ -906,7 +908,7 @@ fn test_sorter() {
 			i: 102
 		}
 	]
-	cmp := fn (a, b &Ka) int {
+	cmp := fn (a &Ka, b &Ka) int {
 		return compare_strings(a.s, b.s)
 	}
 	arr.sort_with_compare(cmp)

vlib/v/gen/cgen.v

@@ -100,8 +100,8 @@ mut:
 	inside_vweb_tmpl      bool
 	inside_return         bool
 	inside_or_block       bool
+	strs_to_free0         []string // strings.Builder
 	strs_to_free          []string // strings.Builder
-	// strs_to_free0         []string // strings.Builder
 	inside_call           bool
 	has_main              bool
 	inside_const          bool
@@ -111,6 +111,7 @@ mut:
 	match_sumtype_syms    []table.TypeSymbol
 	// tmp_arg_vars_to_free  []string
 	// autofree_pregen       map[string]string
+	// autofree_pregen_buf   strings.Builder
 	// autofree_tmp_vars     []string // to avoid redefining the same tmp vars in a single function
 	called_fn_name        string
 	cur_mod               string
@@ -755,6 +756,9 @@ fn (mut g Gen) stmt(node ast.Stmt) {
 	defer {
 		// If we have temporary string exprs to free after this statement, do it. e.g.:
 		// `foo('a' + 'b')` => `tmp := 'a' + 'b'; foo(tmp); string_free(&tmp);`
+		if g.pref.autofree {
+			g.autofree_call_postgen()
+		}
 		/*
 		if g.pref.autofree { // && !g.inside_or_block {
 			// TODO remove the inside_or_block hack. strings are not freed in or{} atm
@@ -835,14 +839,14 @@ fn (mut g Gen) stmt(node ast.Stmt) {
 		}
 		ast.ExprStmt {
 			g.write_v_source_line_info(node.pos)
-			af := g.pref.autofree && node.expr is ast.CallExpr && !g.is_builtin_mod
-			if af {
-				g.autofree_call_pregen(node.expr as ast.CallExpr)
-			}
+			// af := g.pref.autofree && node.expr is ast.CallExpr && !g.is_builtin_mod
+			// if af {
+			// g.autofree_call_pregen(node.expr as ast.CallExpr)
+			// }
 			g.expr(node.expr)
-			if af {
-				g.autofree_call_postgen()
-			}
+			// if af {
+			// g.autofree_call_postgen()
+			// }
 			if g.inside_ternary == 0 && !node.is_expr && !(node.expr is ast.IfExpr) {
 				g.writeln(';')
 			}
@@ -1011,9 +1015,9 @@ fn (mut g Gen) stmt(node ast.Stmt) {
 			af := g.pref.autofree && node.exprs.len > 0 && node.exprs[0] is ast.CallExpr && !g.is_builtin_mod
 			if g.pref.autofree {
 				g.writeln('// ast.Return free')
-				if af {
-					g.autofree_call_pregen(node.exprs[0] as ast.CallExpr)
-				}
+				// if af {
+				// g.autofree_call_pregen(node.exprs[0] as ast.CallExpr)
+				// }
 				// g.autofree_scope_vars(node.pos.pos)
 				g.write_autofree_stmts_when_needed(node)
 			}
@@ -1390,11 +1394,12 @@ fn (mut g Gen) gen_assign_stmt(assign_stmt ast.AssignStmt) {
 		}
 	}
 	// Autofree tmp arg vars
-	first_right := assign_stmt.right[0]
-	af := g.pref.autofree && first_right is ast.CallExpr && !g.is_builtin_mod
-	if af {
-		g.autofree_call_pregen(first_right as ast.CallExpr)
-	}
+	// first_right := assign_stmt.right[0]
+	// af := g.pref.autofree && first_right is ast.CallExpr && !g.is_builtin_mod
+	// if af {
+	// g.autofree_call_pregen(first_right as ast.CallExpr)
+	// }
+	//
 	//
 	// Handle optionals. We need to declare a temp variable for them, that's why they are handled
 	// here, not in call_expr().
@@ -1422,9 +1427,9 @@ fn (mut g Gen) gen_assign_stmt(assign_stmt ast.AssignStmt) {
 			gen_or = true
 			g.or_block(tmp_opt, call_expr.or_block, call_expr.return_type)
 			g.writeln('/*=============ret*/')
-			if af && is_optional {
-				g.autofree_call_postgen()
-			}
+			// if af && is_optional {
+			// g.autofree_call_postgen()
+			// }
 			// return
 		}
 	}
@@ -1987,7 +1992,15 @@ fn (mut g Gen) expr(node ast.Expr) {
 			// if g.fileis('1.strings') {
 			// println('before:' + node.autofree_pregen)
 			// }
-			if g.pref.autofree {
+			if g.pref.autofree && !g.is_builtin_mod && g.strs_to_free0.len == 0 {
+				// if len != 0, that means we are handling call expr inside call expr (arg)
+				// and it'll get messed up here, since it's handled recursively in autofree_call_pregen()
+				// so just skip it
+				g.autofree_call_pregen(node)
+				if g.strs_to_free0.len > 0 {
+					g.insert_before_stmt(g.strs_to_free0.join('\n'))
+				}
+				g.strs_to_free0 = []
 				// println('pos=$node.pos.pos')
 			}
 			// if g.pref.autofree && node.autofree_pregen != '' { // g.strs_to_free0.len != 0 {

vlib/v/gen/fn.v

@@ -620,7 +620,7 @@ fn (mut g Gen) fn_call(node ast.CallExpr) {
 }
 
 fn (mut g Gen) autofree_call_pregen(node ast.CallExpr) {
-	g.writeln('// autofree_call()')
+	// g.writeln('// autofree_call_pregen()')
 	// Create a temporary var before fn call for each argument in order to free it (only if it's a complex expression,
 	// like `foo(get_string())` or `foo(a + b)`
 	mut free_tmp_arg_vars := g.autofree && g.pref.experimental && !g.is_builtin_mod &&
@@ -648,19 +648,22 @@ fn (mut g Gen) autofree_call_pregen(node ast.CallExpr) {
 		// g.called_fn_name = name
 		// used := t in g.autofree_tmp_vars
 		used := scope.known_var(t)
-		if used {
-			g.write('$t = ')
+		mut s := if used {
+			'$t = '
 		} else {
-			g.write('string $t = ')
 			scope.register(t, ast.Var{
 				name: t
 				typ: table.string_type
 				is_arg: true // TODO hack so that it's not freed twice when out of scope. it's probably better to use one model
 			})
+			'string $t = '
 			// g.autofree_tmp_vars << t
 		}
-		g.expr(arg.expr)
-		g.writeln(';// new af pre')
+		// g.expr(arg.expr)
+		s += g.write_expr_to_string(arg.expr)
+		// g.writeln(';// new af pre')
+		s += ';// new af2 pre'
+		g.strs_to_free0 << s
 		// Now free the tmp arg vars right after the function call
 		g.strs_to_free << t
 		// g.strs_to_free << 'string_free(&$t);'

vlib/v/tests/valgrind/1.strings_and_arrays.v

@@ -13,14 +13,14 @@ fn foo() {
 	// nums.free() // this should result in a double free and a CI error
 }
 
-fn handle_strings(s, p string) int {
+fn handle_strings(s string, p string) int {
 	return 0
 }
 
 fn handle_int(n int) {
 }
 
-fn add_strings(a, b string) string {
+fn add_strings(a string, b string) string {
 	return a + b
 }
 
@@ -120,6 +120,25 @@ fn optional_return() {
 	}
 }
 
+fn handle_string(s string) bool {
+	return true
+}
+
+fn if_cond() {
+	// handle_string('1' + '2')
+	if handle_string('1' + '2') {
+		// if '1' + '2' == '12' {
+		println('yes')
+	} else {
+		println('no')
+	}
+}
+
+fn addition_with_tmp_expr() {
+	x := 1 + handle_strings('a' + 'b', 'c')
+	println(x)
+}
+
 fn tt() {
 	// time.parse_rfc2822('1234')
 }
@@ -136,6 +155,8 @@ fn main() {
 	optional_str()
 	optional_return()
 	// str_replace()
+	if_cond()
+	addition_with_tmp_expr()
 	println('end')
 }