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autofree: fix free before return

pull/9358/head
Alexander Medvednikov 2021-03-18 05:41:50 +03:00
parent 88097125f7
commit 4e62bc0b81
2 changed files with 20 additions and 14 deletions
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27
vlib/v/gen/c/cgen.v
View File

@ -1768,7 +1768,7 @@ fn (mut g Gen) gen_asm_stmt(stmt ast.AsmStmt) {
} else {
g.write(' ')
}
// swap destionation and operands for att syntax
// swap destionation and operands for att syntax
if template.args.len != 0 {
template.args.prepend(template.args[template.args.len - 1])
template.args.delete(template.args.len - 1)
@ -4539,7 +4539,7 @@ fn (mut g Gen) return_statement(node ast.Return) {
styp := g.typ(g.fn_decl.return_type)
g.writeln('return ($styp){0};')
} else {
if g.is_autofree && !g.is_builtin_mod {
if g.is_autofree {
g.writeln('// free before return (no values returned)')
g.autofree_scope_vars(node.pos.pos - 1, node.pos.line_nr, true)
}
@ -4680,13 +4680,24 @@ fn (mut g Gen) return_statement(node ast.Return) {
g.writeln('return $opt_tmp;')
return
}
// autofree before `return`
// set free_parent_scopes to true, since all variables defined in parent
// scopes need to be freed before the return
if g.is_autofree {
expr := node.exprs[0]
if expr is ast.Ident {
g.returned_var_name = expr.name
}
g.autofree_scope_vars(node.pos.pos - 1, node.pos.line_nr, true)
}
// free := g.is_autofree && !g.is_builtin_mod // node.exprs[0] is ast.CallExpr
// Create a temporary variable for the return expression
free := !g.is_builtin_mod // node.exprs[0] is ast.CallExpr
mut tmp := ''
if free {
// `return foo(a, b, c)`
// `tmp := foo(a, b, c); free(a); free(b); free(c); return tmp;`
// Save return value in a temp var so that it all args (a,b,c) can be freed
// Save return value in a temp var so that all args (a,b,c) can be freed
// Don't use a tmp var if a variable is simply returned: `return x`
if node.exprs[0] !is ast.Ident {
tmp = g.new_tmp_var()
@ -4712,18 +4723,8 @@ fn (mut g Gen) return_statement(node ast.Return) {
g.expr_with_cast(node.exprs[0], node.types[0], g.fn_decl.return_type)
}
if free {
expr := node.exprs[0]
if expr is ast.Ident {
g.returned_var_name = expr.name
}
g.writeln(';')
has_semicolon = true
// autofree before `return`
// set free_parent_scopes to true, since all variables defined in parent
// scopes need to be freed before the return
if g.pref.autofree {
g.autofree_scope_vars(node.pos.pos - 1, node.pos.line_nr, true)
}
if tmp != '' {
g.write('return $tmp')
has_semicolon = false

7
vlib/v/tests/valgrind/1.strings_and_arrays.v
View File

@ -318,6 +318,11 @@ fn get_user() User {
return user
}
fn get_user2() User {
users := [User{'Peter', 25}, User{'Alice', 21}]
return users[0] // has to be cloned, since `users` are going to be freed at the end of the function
}
fn string_array_get() {
s := ['a', 'b', 'c']
x := s[0]
@ -361,7 +366,7 @@ fn main() {
free_before_break()
// free_map()
// loop_map()
// free_array_except_returned_element()
free_array_except_returned_element()
println('end')
}