[Generic] change the value of an attribute

[charfi asma]

----- Message d'origine ----
De : Andi Hellmund <mail@andihellmund.com>
À : charfi asma <charfiasma@yahoo.fr>
Cc : gcc-help@gcc.gnu.org
Envoyé le : Jeu 27 janvier 2011, 1h 23min 01s
Objet : Re: [Generic] change the value of an attribute

On 01/26/2011 05:08 PM, charfi asma wrote:
> Hello every body,
>
> I have a class named MyClass, that has an operation (MyOperation1) and this
> operation change the value of MyAttribute1 of type Integer.
>
> to call my operation in the main I added a hidden argument (this)
>
> main
> {
>
>      tree myClass_type = make_node(RECORD_TYPE);
>      TYPE_PACKED(myClass_type) = false;
>      TYPE_NAME(myClass_type) = get_identifier("MyClass");
>
> //properties:
>
>      tree myAttribute1_type = integer_type_node;
>      tree myAttribute1_tree = build_decl(BUILTINS_LOCATION, FIELD_DECL,
> get_identifier("MyAttribute1"), myAttribute1_type);
>      DECL_CONTEXT(myAttribute1_tree) = myClass_type;
>      DECL_PACKED(myAttribute1_tree) = false;
>      TYPE_FIELDS(myClass_type) = myAttribute1_tree;
>
> //operations:
>
>      tree myOperation2_type = build_function_type_list(void_type_node,
> NULL_TREE);
>
>      tree myOperation2_decl = build_decl(BUILTINS_LOCATION, FUNCTION_DECL,
> get_identifier("MyOperation2"), myOperation2_type);
>      tree myOperation2_tree = create_operation(myClass_type, 
>myOperation2_decl);
> // find bellow
>
>      DECL_CONTEXT(myOperation2_tree) = myClass_type;
>      DECL_PACKED(myOperation2_tree) = false;
>      TYPE_METHODS(myClass_type) =  myOperation2_tree;
>
>      layout_type(myClass_type);
>      rest_of_type_compilation(myClass_type, 1);
>
> // create instance
>
>      tree x_tree = build_decl(BUILTINS_LOCATION, VAR_DECL, 
get_identifier("x"),
> myClass_type);
>      TREE_STATIC(x_tree) = false;
>      TREE_PUBLIC(x_tree) = true;
>      DECL_CONTEXT(x_tree) = main_fn_decl;
>      TREE_USED(x_tree) = true;
>
>      append_to_statement_list(x_tree,&main_stmts);
>      layout_decl(x_tree, false);
>      rest_of_decl_compilation(x_tree, 1, 0);
>      VEC_safe_push( tree, gc, global_decls_vec, x_tree );
>
> // call operation
>
>      tree target_ptr = build1(ADDR_EXPR,
> build_pointer_type(TREE_TYPE(x_tree)),x_tree); //&x
>
>      tree call_myOperation2 = build_call_expr(myOperation2_tree, 1,  
>target_ptr);
>      append_to_statement_list(call_myOperation2,&main_stmts);
>
> ...
> }
>
> Now, I want to modify the value of MyAttribute1 in the operation body. (
> this.MyAttribute1=10)
>
> tree create_operation(tree class_t, tree operation )
> {
>
>
> // set argument manually
>
> tree __func_param = NULL_TREE;
> tree parm_type = build_pointer_type(class_t);
> tree parm = build_decl (BUILTINS_LOCATION, PARM_DECL, get_identifier("this"),
> parm_type);
> TREE_CONSTANT (parm) = true;
> TREE_READONLY (parm) = true;
>
>
> DECL_CHAIN (parm) = __func_param;
> __func_param = parm;
> DECL_ARGUMENTS(operation)=(__func_param);
>
>
> // return type preparation
> tree __func_result = build_decl(BUILTINS_LOCATION, RESULT_DECL, NULL_TREE,
> TREE_TYPE(operation));
> DECL_CONTEXT(__func_result) = operation;
> DECL_ARTIFICIAL(__func_result) = true;
> DECL_IGNORED_P(__func_result) = true;
> DECL_RESULT(operation) = __func_result;
>
> // debug tree needed for bind exp
> tree __func_art_block = build_block(NULL_TREE, NULL_TREE, NULL_TREE, 
>NULL_TREE);
> DECL_INITIAL(operation) = __func_art_block;
>
> tree func_stmts = alloc_stmt_list ();
>
> //set the body
>
>
>      tree t = TREE_TYPE(TREE_TYPE(parm));
>
>      tree ref = build1 (INDIRECT_REF, t, parm);
>
>      tree __struct_field0 = TYPE_FIELDS(TREE_TYPE(ref));
>
>      tree __struct_access_0 = build3(COMPONENT_REF, 
TREE_TYPE(__struct_field0),
> ref, __struct_field0, NULL_TREE);
>
>      tree modify_att_tree = build2(MODIFY_EXPR, TREE_TYPE(__struct_field0),
> __struct_access_0, build_int_cst(integer_type_node, 10));
>
> append_to_statement_list(modify_att_tree,&func_stmts);
>
> /********************************add the final return statement
> *********************************/
>
>    tree func_ret_expr = build1(RETURN_EXPR, void_type_node, NULL_TREE);
>
> append_to_statement_list(func_ret_expr,&func_stmts);
>
>
> // bind and gimplification
> DECL_SAVED_TREE(operation) = build3(BIND_EXPR, void_type_node, NULL_TREE,
> func_stmts, __func_art_block);
>
> // pass to middle end
> gimplify_function_tree(operation);
> cgraph_node(operation);
> cgraph_finalize_function(operation,false);
>
> return operation;
>
> }
>
> I get error while calling gimplify_function_tree(operation); it comes from
> COMPONENT_REF gimplification (call to gimplify_compound_lval)
>
> this is the debug output:
>
> (gdb) n
> 7771      bind = gimplify_body (&DECL_SAVED_TREE (fndecl), fndecl, true);
> (gdb) n
>
> Program received signal SIGSEGV, Segmentation fault.
> size_binop_loc (loc=0, code=EXACT_DIV_EXPR, arg0=0x0, arg1=0xb7572680)
>      at ../../gcc-dev/gcc/fold-const.c:1414
> 1414      tree type = TREE_TYPE (arg0);
>
>
> any idea ?
>
> thank you in advance
>
> Asma
>    
Hey Asma,

the problem in your code is that you access the class/record in 
create_operation() by a COMPONENT_REF although the class/record's layout 
hasn't yet been built. To be clear, you call layout_type() which for 
example sets the offset for each FIELD_DECL after create_operation(). 
Though, when the gimplifier tries to access the record, it requires the 
offset of the FIELD_DECL to be available, but in your case, it is NULL_TREE.

Since layout_type() for RECORD_TYPES doesn't work on TYPE_METHODS, you 
could call layout_type() before processing the operations. By the way

DECL_PACKED(myOperation2_tree) = false;

does not work for FUNCTION_DECL, but only for FIELD_DECLs.

Andi

Hello,

thank you very much Ian and Andi ;) 

it works now (I call layout_type()  before create_operation() as Andi suggest ) 
. 


I could never guess it alone  :D

Asma