+ tree func_params;
+ /* The LHS parameter contains the expression 'outervar->memberspec';
+ we need to transform it into '&((typeof(outervar) *) 0)->memberspec',
+ where memberspec may be arbitrarily complex (e.g., 'g->f.d[2].g[3]').
+ */
+ tree offs
+ = objc_substitute_decl
+ (lhs, outervar, convert (TREE_TYPE (outervar), integer_zero_node));
+ tree func
+ = (flag_objc_direct_dispatch
+ ? objc_assign_ivar_fast_decl
+ : objc_assign_ivar_decl);
+
+ offs = convert (integer_type_node, build_unary_op (input_location,
+ ADDR_EXPR, offs, 0));
+ offs = fold (offs);
+ func_params = tree_cons (NULL_TREE,
+ convert (objc_object_type, rhs),
+ tree_cons (NULL_TREE, convert (objc_object_type, outervar),
+ tree_cons (NULL_TREE, offs,
+ NULL_TREE)));
+
+ assemble_external (func);
+ return build_function_call (func, func_params);
+}
+
+static tree
+objc_build_global_assignment (tree lhs, tree rhs)
+{
+ tree func_params = tree_cons (NULL_TREE,
+ convert (objc_object_type, rhs),
+ tree_cons (NULL_TREE, convert (build_pointer_type (objc_object_type),
+ build_unary_op (input_location, ADDR_EXPR, lhs, 0)),
+ NULL_TREE));
+
+ assemble_external (objc_assign_global_decl);
+ return build_function_call (objc_assign_global_decl, func_params);
+}
+
+static tree
+objc_build_strong_cast_assignment (tree lhs, tree rhs)
+{
+ tree func_params = tree_cons (NULL_TREE,
+ convert (objc_object_type, rhs),
+ tree_cons (NULL_TREE, convert (build_pointer_type (objc_object_type),
+ build_unary_op (input_location, ADDR_EXPR, lhs, 0)),
+ NULL_TREE));
+
+ assemble_external (objc_assign_strong_cast_decl);
+ return build_function_call (objc_assign_strong_cast_decl, func_params);
+}
+
+static int
+objc_is_gcable_p (tree expr)
+{
+ return (TREE_CODE (expr) == COMPONENT_REF
+ ? objc_is_gcable_p (TREE_OPERAND (expr, 1))
+ : TREE_CODE (expr) == ARRAY_REF
+ ? (objc_is_gcable_p (TREE_TYPE (expr))
+ || objc_is_gcable_p (TREE_OPERAND (expr, 0)))
+ : TREE_CODE (expr) == ARRAY_TYPE
+ ? objc_is_gcable_p (TREE_TYPE (expr))
+ : TYPE_P (expr)
+ ? objc_is_gcable_type (expr, 1)
+ : (objc_is_gcable_p (TREE_TYPE (expr))
+ || (DECL_P (expr)
+ && lookup_attribute ("objc_gc", DECL_ATTRIBUTES (expr)))));
+}
+
+static int
+objc_is_ivar_reference_p (tree expr)
+{
+ return (TREE_CODE (expr) == ARRAY_REF
+ ? objc_is_ivar_reference_p (TREE_OPERAND (expr, 0))
+ : TREE_CODE (expr) == COMPONENT_REF
+ ? TREE_CODE (TREE_OPERAND (expr, 1)) == FIELD_DECL
+ : 0);
+}
+
+static int
+objc_is_global_reference_p (tree expr)
+{
+ return (TREE_CODE (expr) == INDIRECT_REF || TREE_CODE (expr) == PLUS_EXPR
+ ? objc_is_global_reference_p (TREE_OPERAND (expr, 0))
+ : DECL_P (expr)
+ ? (!DECL_CONTEXT (expr) || TREE_STATIC (expr))
+ : 0);
+}
+
+tree
+objc_generate_write_barrier (tree lhs, enum tree_code modifycode, tree rhs)
+{
+ tree result = NULL_TREE, outer;
+ int strong_cast_p = 0, outer_gc_p = 0, indirect_p = 0;
+
+ /* See if we have any lhs casts, and strip them out. NB: The lvalue casts
+ will have been transformed to the form '*(type *)&expr'. */
+ if (TREE_CODE (lhs) == INDIRECT_REF)
+ {
+ outer = TREE_OPERAND (lhs, 0);
+
+ while (!strong_cast_p
+ && (CONVERT_EXPR_P (outer)
+ || TREE_CODE (outer) == NON_LVALUE_EXPR))
+ {
+ tree lhstype = TREE_TYPE (outer);
+
+ /* Descend down the cast chain, and record the first objc_gc
+ attribute found. */
+ if (POINTER_TYPE_P (lhstype))
+ {
+ tree attr
+ = lookup_attribute ("objc_gc",
+ TYPE_ATTRIBUTES (TREE_TYPE (lhstype)));
+
+ if (attr)
+ strong_cast_p = 1;
+ }
+
+ outer = TREE_OPERAND (outer, 0);
+ }
+ }
+
+ /* If we have a __strong cast, it trumps all else. */
+ if (strong_cast_p)
+ {
+ if (modifycode != NOP_EXPR)
+ goto invalid_pointer_arithmetic;
+
+ if (warn_assign_intercept)
+ warning (0, "strong-cast assignment has been intercepted");
+
+ result = objc_build_strong_cast_assignment (lhs, rhs);
+
+ goto exit_point;
+ }
+
+ /* the lhs must be of a suitable type, regardless of its underlying
+ structure. */
+ if (!objc_is_gcable_p (lhs))
+ goto exit_point;
+
+ outer = lhs;
+
+ while (outer
+ && (TREE_CODE (outer) == COMPONENT_REF
+ || TREE_CODE (outer) == ARRAY_REF))
+ outer = TREE_OPERAND (outer, 0);
+
+ if (TREE_CODE (outer) == INDIRECT_REF)
+ {
+ outer = TREE_OPERAND (outer, 0);
+ indirect_p = 1;
+ }
+
+ outer_gc_p = objc_is_gcable_p (outer);
+
+ /* Handle ivar assignments. */
+ if (objc_is_ivar_reference_p (lhs))
+ {
+ /* if the struct to the left of the ivar is not an Objective-C object (__strong
+ doesn't cut it here), the best we can do here is suggest a cast. */
+ if (!objc_is_gcable_type (TREE_TYPE (outer), 0))
+ {
+ /* We may still be able to use the global write barrier... */
+ if (!indirect_p && objc_is_global_reference_p (outer))
+ goto global_reference;
+
+ suggest_cast:
+ if (modifycode == NOP_EXPR)
+ {
+ if (warn_assign_intercept)
+ warning (0, "strong-cast may possibly be needed");
+ }
+
+ goto exit_point;
+ }
+
+ if (modifycode != NOP_EXPR)
+ goto invalid_pointer_arithmetic;
+
+ if (warn_assign_intercept)
+ warning (0, "instance variable assignment has been intercepted");
+
+ result = objc_build_ivar_assignment (outer, lhs, rhs);
+
+ goto exit_point;
+ }
+
+ /* Likewise, intercept assignment to global/static variables if their type is
+ GC-marked. */
+ if (objc_is_global_reference_p (outer))
+ {
+ if (indirect_p)
+ goto suggest_cast;
+
+ global_reference:
+ if (modifycode != NOP_EXPR)
+ {
+ invalid_pointer_arithmetic:
+ if (outer_gc_p)
+ warning (0, "pointer arithmetic for garbage-collected objects not allowed");
+
+ goto exit_point;
+ }
+
+ if (warn_assign_intercept)
+ warning (0, "global/static variable assignment has been intercepted");
+
+ result = objc_build_global_assignment (lhs, rhs);
+ }
+
+ /* In all other cases, fall back to the normal mechanism. */
+ exit_point:
+ return result;
+}
+
+struct GTY(()) interface_tuple {
+ tree id;
+ tree class_name;
+};
+
+static GTY ((param_is (struct interface_tuple))) htab_t interface_htab;
+
+static hashval_t
+hash_interface (const void *p)
+{
+ const struct interface_tuple *d = (const struct interface_tuple *) p;
+ return IDENTIFIER_HASH_VALUE (d->id);
+}
+
+static int
+eq_interface (const void *p1, const void *p2)
+{
+ const struct interface_tuple *d = (const struct interface_tuple *) p1;
+ return d->id == p2;
+}
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