On Sun, Aug 3, 2014 at 6:58 PM, Prathamesh Kulkarni
<bilbotheelffri...@gmail.com> wrote:
> On Tue, Jul 29, 2014 at 4:29 PM, Richard Biener
> <richard.guent...@gmail.com> wrote:
>> On Mon, Jul 28, 2014 at 10:02 PM, Prathamesh Kulkarni
>> <bilbotheelffri...@gmail.com> wrote:
>>> I am having few issues replacing op in c_expr.
>>> I thought of following possibilities:
>>>
>>> a) create a new vec<cpp_token> vector new_code.
>>> for each token in code
>>> {
>>> if token.type is not CPP_NAME
>>> new_code.safe_push (token);
>>> else
>>> {
>>> cpp_token new_token =
>>> ??? create new token of type CPP_NAME
>>> with contents as name of operator ???
>>> }
>>> }
>>>
>>> I tried to go this way, but am stuck with creating a new token type.
>>> i started by:
>>> cpp_token new_token = token; // get same attrs as token.
>>> CPP_HASHNODE (new_token.val.node.node)->ident.str = name of operator.
>>> CPP_HASHNODE (new_token.val.node.node)->ident.len = len of operator name.
>>> name of operator is obtained from opers[i] in parse_for.
>>>
>>> however this does not work because I guess
>>> new_token = token, shallow copies
>>> the token (default assignment operator, i didn't find an overloaded
>>> version).
>>>
>>> b) create new struct c_expr_elem and use
>>> vec<c_expr_elem> code, instead of vec<cpp_token> code;
>>>
>>> sth like:
>>> struct c_expr_elem
>>> {
>>> enum c_expr_elem_type { ID, TOKEN };
>>> enum c_expr_elem_type type;
>>>
>>> union {
>>> cpp_token token;
>>> const char *id;
>>> };
>>> };
>>>
>>> while replacing op, compare token with op, and if it matches,
>>> create a new c_expr_elem with type = ID, and id = name of operator.
>>> This shall probably work, but shall require many changes to other parts
>>> since we change c_expr::code.
>>>
>>> I would like to hear any other suggestions.
>>
>> Together with the vector of tokens recorded at parse_c_expr time
>> record a vector of token mappings (op -> plus, op2 -> ...) and do
>> the replacement at code-generation time where we also special-case
>> captures.
>>
>> Yeah, it's a but unfortunate that c_expr parsing is done the way it
>> is done....
> Thanks. I guess we would require a multi-map for this since there can
> be many operators
> (op -> [plus, minus], op2 -> [negate]) ?
Well, it would be enough to attach the mapping to c_expr()s after the
AST lowering when there is at most one? Because obviously
code-generation cannot know which to replace.
> Unfortunately, I somehow seem to have missed your response and ended up with a
> hackish way of doing it, although it works. I will soon change that to
> use token mappings.
>
> I mostly followed b), except i made it sub-class of cpp_token, so the
> other code using c_expr::code
> (outline_c_expr, c_expr::gen_transform) did not require changes except
> for special-casing op.
Indeed not too ugly. Still at the point where you replace in the for()
processing
- operand *result_op = replace_id (s->result, user_id, opers[i]);
+
+ operand *result_op;
+ if (is_a<c_expr *> (s->result))
+ result_op = replace_op_in_c_expr (s->result, user_id, opers[i]);
+ else
+ result_op = replace_id (s->result, user_id, opers[i]);
+
+
it should be "easy" to attach a replacemet vector/map to the c_expr
and use that duing code-generation.
Note that sub-expressions can also be c_exprs, thus
(match-and-simplify
(....)
(plus { ... } @2))
I don't think your patch covers that. That is, you should add
c_expr handing to replace_id instead.
Richard.
> * genmatch.c (c_expr::elem): New struct.
> (c_expr::code): Change type to vec<c_expr::elem>.
> (replace_op_in_c_expr): New function.
> (c_expr::gen_transform): Adjust to changes in c_expr.
> (outline_c_expr): Likewise.
> (parse_c_expr): Likewise.
> (parse_for): Call replace_op_in_c_expr.
>
> Thanks,
> Prathamesh
>
>>
>> Richard.
>>
>>> Thanks,
>>> Prathamesh.
