[vala/staging] codegen: Access of stack allocated struct is guaranteed to be non null

[Rico Tzschichholz <ricotz src gnome org>]

commit ca3da69b2bda18b8b081c2dae48f2ccff93f165a
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Mon Jan 24 10:17:46 2022 +0100

    codegen: Access of stack allocated struct is guaranteed to be non null
    
    Found by -Werror=address with GCC 12
    
    See https://gitlab.gnome.org/GNOME/vala/issues/1282

 codegen/valaccodebasemodule.vala   | 2 ++
 tests/structs/bug777194.c-expected | 8 ++++----
 vala/valaaddressofexpression.vala  | 4 ++++
 vala/valamemberaccess.vala         | 7 ++++++-
 4 files changed, 16 insertions(+), 5 deletions(-)
---
diff --git a/codegen/valaccodebasemodule.vala b/codegen/valaccodebasemodule.vala
index 9ebcfbac6..2e34003f1 100644
--- a/codegen/valaccodebasemodule.vala
+++ b/codegen/valaccodebasemodule.vala
@@ -5593,6 +5593,8 @@ public abstract class Vala.CCodeBaseModule : CodeGenerator {
                        innercexpr = new CCodeUnaryExpression (CCodeUnaryOperator.ADDRESS_OF, innercexpr);
                }
                set_cvalue (expr, new CCodeCastExpression (innercexpr, get_ccode_name (expr.type_reference)));
+               //TODO Use get_non_null (expr.inner.target_value)
+               ((GLibValue) expr.target_value).non_null = expr.is_non_null ();
 
                if (expr.type_reference is DelegateType) {
                        var target = get_delegate_target (expr.inner);
diff --git a/tests/structs/bug777194.c-expected b/tests/structs/bug777194.c-expected
index 927043755..055c37c70 100644
--- a/tests/structs/bug777194.c-expected
+++ b/tests/structs/bug777194.c-expected
@@ -238,7 +238,7 @@ _vala_main (void)
        _tmp4_ = tu;
        _tmp4__length1 = tu_length1;
        bar (_tmp4_, (gint) _tmp4__length1);
-       _tmp5_ = (((guint8*) (&fstack)) != NULL) ? _vala_array_dup1 ((guint8*) (&fstack), sizeof (Foo) / 
sizeof (guint8)) : ((guint8*) (&fstack));
+       _tmp5_ = _vala_array_dup1 ((guint8*) (&fstack), sizeof (Foo) / sizeof (guint8));
        _tmp5__length1 = sizeof (Foo) / sizeof (guint8);
        to = (g_free (to), NULL);
        to = _tmp5_;
@@ -263,7 +263,7 @@ _vala_main (void)
        _tmp11__length1 = tu_length1;
        bar (_tmp11_, (gint) _tmp11__length1);
        _tmp12_ = fstack;
-       _tmp13_ = (((guint8*) (&_tmp12_)) != NULL) ? _vala_array_dup2 ((guint8*) (&_tmp12_), sizeof (Foo) / 
sizeof (guint8)) : ((guint8*) (&_tmp12_));
+       _tmp13_ = _vala_array_dup2 ((guint8*) (&_tmp12_), sizeof (Foo) / sizeof (guint8));
        _tmp13__length1 = sizeof (Foo) / sizeof (guint8);
        to = (g_free (to), NULL);
        to = _tmp13_;
@@ -310,7 +310,7 @@ _vala_main (void)
        _tmp22_ = tu;
        _tmp22__length1 = tu_length1;
        _vala_assert (_tmp22__length1 == 4, "tu.length == 4");
-       _tmp23_ = (((guint8*) (&i32)) != NULL) ? _vala_array_dup4 ((guint8*) (&i32), sizeof (gint32) / sizeof 
(guint8)) : ((guint8*) (&i32));
+       _tmp23_ = _vala_array_dup4 ((guint8*) (&i32), sizeof (gint32) / sizeof (guint8));
        _tmp23__length1 = sizeof (gint32) / sizeof (guint8);
        to = (g_free (to), NULL);
        to = _tmp23_;
@@ -332,7 +332,7 @@ _vala_main (void)
        _tmp26_ = tu;
        _tmp26__length1 = tu_length1;
        _vala_assert (_tmp26__length1 == 8, "tu.length == 8");
-       _tmp27_ = (((guint8*) (&u64)) != NULL) ? _vala_array_dup5 ((guint8*) (&u64), sizeof (guint64) / 
sizeof (guint8)) : ((guint8*) (&u64));
+       _tmp27_ = _vala_array_dup5 ((guint8*) (&u64), sizeof (guint64) / sizeof (guint8));
        _tmp27__length1 = sizeof (guint64) / sizeof (guint8);
        to = (g_free (to), NULL);
        to = _tmp27_;
diff --git a/vala/valaaddressofexpression.vala b/vala/valaaddressofexpression.vala
index ff542835b..dbe9cff1a 100644
--- a/vala/valaaddressofexpression.vala
+++ b/vala/valaaddressofexpression.vala
@@ -82,6 +82,10 @@ public class Vala.AddressofExpression : Expression {
                return inner.is_accessible (sym);
        }
 
+       public override bool is_non_null () {
+               return inner.is_non_null ();
+       }
+
        public override bool check (CodeContext context) {
                if (checked) {
                        return !error;
diff --git a/vala/valamemberaccess.vala b/vala/valamemberaccess.vala
index d27a4266a..f083da911 100644
--- a/vala/valamemberaccess.vala
+++ b/vala/valamemberaccess.vala
@@ -203,7 +203,12 @@ public class Vala.MemberAccess : Expression {
                if (c != null) {
                        return (c is EnumValue || !c.type_reference.nullable);
                } else if (l != null) {
-                       return (l.variable_type is ArrayType && ((ArrayType) 
l.variable_type).inline_allocated);
+                       unowned DataType type = l.variable_type;
+                       if (type is ArrayType) {
+                               return ((ArrayType) type).inline_allocated;
+                       } else {
+                               return type.is_real_non_null_struct_type () || type.is_non_null_simple_type 
();
+                       }
                } else if (m != null) {
                        return (m.binding == MemberBinding.STATIC || prototype_access);
                } else {