[cfe-dev] Matching method defined outside a class declaration

[Manuel Klimek]

On Tue, Sep 17, 2013 at 3:17 PM, Jesper Eskilson <jesper.eskilson at iar.com>wrote:

> On 09/17/2013 02:50 PM, Manuel Klimek wrote:
>
>  On Tue, Sep 17, 2013 at 2:24 PM, Jesper Eskilson <jesper.eskilson at iar.com<mailto:
>> jesper.eskilson at iar.**com <jesper.eskilson at iar.com>>> wrote:
>>
>>
>>     Hello,
>>
>>     I'm trying to write an AST matcher rule which is able to match
>>     method definitions. Given the following C++ source code:
>>
>>         class B
>>         {
>>           void foo();
>>           void bar() {
>>             int a_local_variable_in_bar;
>>           }
>>         };
>>
>>         void B::foo()
>>         {
>>           int a_local_variable_in_foo;
>>         }
>>
>>         B b
>>
>>         int main()
>>         {
>>         }
>>
>>
>>     I would like a matcher which can tell me where instances of B are
>>     created and also give me the definitions of its methods (in this
>>     case "foo" and "bar").
>>
>>           StatementMatcher m = constructExpr(
>>               hasType(
>>                   recordDecl(**isSameOrDerivedFrom("B"),
>>         hasMethod(methodDecl(**isDefinition()).bind("method")**))));
>>
>>
>>     But it will only give me the definition of "bar", and not the
>>     defintion of "foo" which is declared outside the class.
>>
>>
>> This is because hasMethod will not give you anything outside of the class
>> definition. The reason is that you often don't see out-of-class method
>> definitions of when you have a class definition.
>>
>> If you already know the name of the class (as you specify it in your
>> matcher), why do you want to write this matcher in the first place? You'll
>> not be able to match all constructor calls and method definitions in
>> general, as classes may be instantiated in a translation unit where not all
>> method definitions are visible.
>>
>> If you have more details on what you're actually trying to do (on a
>> higher level) we might be able to help more...
>>
>>     If I cannot do this with matchers, is there a way to get to the
>>     definition of "foo" given the declaration of the class B?
>>
>>
>> No, as you might see the class definition in a header where foo is not
>> visible. Usually you'll want to go the other way - find all method
>> definitions of class "B".
>>
>>
> I have a bunch of class instantiations in a large codebase which look like
> this
>
> A a1("banana", new B1);
> A a2("apple", new B2);
> A a3("ananas", new B2);
>
> B1, B2, B3, all inherit from B which defines a method "foo" (outside the
> declaration of B). This definition may or may not be overridden in B1/B2/B3.
>
> I want to be able to generate output on the form:
>
> banana:
>     void foo() { /* this is the foo implementation in class B1 */ }
> apple:
>     void foo() { /* this is the foo implementation in class B2 */ }
> ananas:
>     void foo() { /* this is the foo implementation in class B3 */ }
>
> I was thinking about first matching out all the different definitions of
> foo, and then in a separate matcher match the construction expressions of
> a1-a3, but I'm not sure of the best way to "share" information between
> matchers.


Create intermediate output:
- output all paremeter combinations ("banana", "B1"), ("apple, "B2")
- output all method definitions ("B1", "void foo() { ... }"), ...
store the intermediate results. After running over all translation units,
do a "reduce" step where you combine the information by using the class as
the key


>
>
> --
> *Jesper Eskilson* /Development Engineer/
> IAR Systems AB
> Box 23051, Strandbodgatan 1
> SE-750 23 Uppsala, SWEDEN
> E-mail: jesper.eskilson at iar.com <mailto:jesper.eskilson at iar.**com<jesper.eskilson at iar.com>>
> Website: www.iar.com
> <http://www.iar.com> Twitter: www.twitter.com/iarsystems <
> http://www.twitter.com/**iarsystems <http://www.twitter.com/iarsystems>>
>
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