[cfe-dev] CXCursor_CXXBaseSpecifier for template instantiated base class
Nestal Wan via cfe-dev
cfe-dev at lists.llvm.org
Thu Mar 16 12:07:03 PDT 2017
Do you mean this?
| `-ClassTemplateSpecializationDecl 0x557ff8ef4e10 <line:16:1,
line:25:1> line:17:7 class RecursiveBase definition
| |-public 'class Base':'class Base'
| |-TemplateArgument type 'class Base'
| |-CXXRecordDecl 0x557ff8ef5098 prev 0x557ff8ef4e10 <col:1, col:7>
col:7 implicit class RecursiveBase
| |-AccessSpecDecl 0x557ff8ef5130 <line:19:1, col:7> col:1 public
I can see it from the AST dump, but not know how to get a cursor to it.
On Fri, Mar 17, 2017 at 3:01 AM, Michael <redm at gmx.de> wrote:
> Well, at least for me it didn't really help, it did not do what I would have
> expected it to do... i.e. return the specialized versions of the template,
> "RecursiveBase<Base>" and more importantly it's base "Base" in your example.
>
>
>
> On 03/16/2017 07:16 PM, Nestal Wan wrote:
>>
>> Yes. I think clang_getSpecializedCursorTemplate() will definitely be
>> useful for me. Thanks for the info.
>>
>> On Thu, Mar 16, 2017 at 2:02 AM, Michael via cfe-dev
>> <cfe-dev at lists.llvm.org> wrote:
>>>
>>> This is an interesting question I was also wondering about the other
>>> day...
>>> (sorry, if you were hoping for an answer;)
>>>
>>> The best thing I figured out was: get the type of template parameter
>>> RecursiveBase<Base> (via clang_Type_getTemplateArgumentAsType), then go
>>> to
>>> the referenced template RecursiveBase and do the parameter mapping
>>> myself.
>>> Of course this will get more complicated if that again derives from a
>>> template using that parameter...
>>>
>>> Running the example through "clang++ -Xclang -ast-dump -fsyntax-only .."
>>> I
>>> see the needed ClassTemplateSpecializationDecls, also for further base
>>> templates, carrying the proper specialized parameter types...
>>>
>>> I would have expected clang_getSpecializedCursorTemplate giving me these
>>> specialized versions of the templates, but either I understand it wrong
>>> what
>>> is supposed to do or it's implementation is incomplete here? Some insight
>>> on
>>> this question would be appreciated.
>>>
>>> Thanks
>>>
>>> Michael
>>>
>>>
>>>
>>> On 03/14/2017 05:39 PM, Nestal Wan via cfe-dev wrote:
>>>>
>>>>
>>>> Thanks Adi,
>>>>
>>>> Like you said, I solve the problem by fixing the errors that were
>>>> indicated by the diagnostic messages.
>>>>
>>>> Now I have another question, if you don't mind I keep using this thread.
>>>>
>>>> I wish know the class hierarchy of "Derived". That means getting the
>>>> base class the the instantiated RecursiveBase<Base> template. That
>>>> should be "Base".
>>>>
>>>> When I visit "Dervied", I got a cursor to a CXCursor_CXXBaseSpecifier.
>>>> I tried to get the type by:
>>>>
>>>> CXType recursive_base =
>>>> clang_getCursorType(clang_getCursorDefinition(cxx_base_specifier));
>>>>
>>>> "recursive_base" refers to the RecursiveBase<Base> instantiation. How
>>>> can I get the base type of this class? I know I can get the cursor to
>>>> the template that instantiate it (i.e. template <typename BaseType>
>>>> RecursiveBase), and I can see it inherits "BaseType" by visiting it
>>>> and look for CXCursor_CXXBaseSpecifier. But how can I know "BaseType"
>>>> will become "Base" when we instantiate it? Will the CXType provides me
>>>> this linkage or I need to use LibTooling instead?
>>>>
>>>> Thanks again.
>>>>
>>>> Nestal
>>>>
>>>> On Sun, Mar 12, 2017 at 9:25 PM, Jusufadis Bakamovic <jbakam at gmail.com>
>>>> wrote:
>>>>>
>>>>>
>>>>> It is hard to tell without more context why you're getting this error,
>>>>> but
>>>>> my guess is that you're missing some command line args (i.e. include
>>>>> paths,
>>>>> preprocessor flags, etc.) which is specific to the code you're
>>>>> analyzing
>>>>> and
>>>>> which is required in order to get the parsing stage done right. Very
>>>>> often
>>>>> this is the case and which is why you should, whenever you have doubts,
>>>>> always try to come up with a small reproducible example (without
>>>>> dependencies) and have it validated separately.
>>>>>
>>>>> Additionally, you can try to extract diagnostics for the given
>>>>> translation
>>>>> unit and see if you get any hints there. Normally, you should get hints
>>>>> if
>>>>> clang parser was not able to fully parse the source code because it was
>>>>> missing some information such as failing to find particular headers.
>>>>>
>>>>> Cheers,
>>>>> Adi
>>>>>
>>>>> On 12 March 2017 at 10:13, Nestal Wan <me at nestal.net> wrote:
>>>>>>
>>>>>>
>>>>>> Thanks for the reply.
>>>>>>
>>>>>> -CXXRecordDecl 0x55e6db0f5ad8 <line:53:1, line:59:1> line:53:7 invalid
>>>>>> class
>>>>>> Derived definition
>>>>>>
>>>>>> | |-public 'class Base2'
>>>>>> | |-public 'class Base3'
>>>>>> | |-CXXRecordDecl 0x55e6db0f5df8 <col:1, col:7> col:7 implicit
>>>>>> referenced
>>>>>>
>>>>>> class Derived
>>>>>>
>>>>>> | |-AccessSpecDecl 0x55e6db0f5e88 <line:55:1, col:7> col:1 public
>>>>>> | |-CXXConstructorDecl 0x55e6db0f5ef0 <line:56:2, col:20> col:2
>>>>>> Derived
>>>>>> 'void
>>>>>>
>>>>>> (void)' noexcept-unevaluated 0x55e6db0f5ef0
>>>>>>
>>>>>> | `-CXXMethodDecl 0x55e6db0f5fd0 <line:58:2, col:24> col:7 Func 'void
>>>>>> (void)'
>>>>>> | `-CompoundStmt 0x55e6db0f6118 <col:23, col:24>
>>>>>>
>>>>>>
>>>>>> Sometimes I got "invalid class Derived definition", but if I extract
>>>>>> the
>>>>>> classes in another source file, the result is different:
>>>>>>
>>>>>> |-CXXRecordDecl 0x55ccfcb583b0 <line:33:1, line:39:1> line:33:7 class
>>>>>> Derived
>>>>>>
>>>>>> definition
>>>>>>
>>>>>> | |-public 'RecursiveBase<class Base>':'class RecursiveBase<class
>>>>>> Base>'
>>>>>> | |-public 'class Base2'
>>>>>> | |-public 'class Base3'
>>>>>> | |-CXXRecordDecl 0x55ccfcb58c70 <col:1, col:7> col:7 implicit
>>>>>> referenced
>>>>>>
>>>>>> class Derived
>>>>>>
>>>>>> What does it mean the class definition is invalid? There is no compile
>>>>>> error.
>>>>>>
>>>>>> Nestal
>>>>>>
>>>>>> On Sun, Mar 12, 2017 at 4:46 PM, Jusufadis Bakamovic
>>>>>> <jbakam at gmail.com>
>>>>>> wrote:
>>>>>>>
>>>>>>>
>>>>>>> You should be getting three times the `CXCursor_CXXBaseSpecifier`,
>>>>>>> one
>>>>>>> for
>>>>>>> each class you're inheriting from. I ran the analysis on my machine
>>>>>>> (clang
>>>>>>> 3.8) and that is exactly what I am getting: `RecursiveBase<class
>>>>>>> Base>`,
>>>>>>> `Base2`, `Base3`. Maybe you could use `clang -Xclang -ast-dump
>>>>>>> -fsyntax-only
>>>>>>> <this_demo>` to see the output of Clang's built-in AST dumper. It
>>>>>>> should
>>>>>>> contain these entries. Otherwise, clang version you're running might
>>>>>>> be
>>>>>>> an
>>>>>>> older one.
>>>>>>>
>>>>>>> On 12 March 2017 at 05:09, Nestal Wan via cfe-dev
>>>>>>> <cfe-dev at lists.llvm.org>
>>>>>>> wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>> Hi,
>>>>>>>>
>>>>>>>> When I use clang_visitChildren() to visit a class, I can't get a
>>>>>>>> CXCursor_CXXBaseSpecifier for its base class if the base class is a
>>>>>>>> template. For example:
>>>>>>>>
>>>>>>>> template <typename BaseType>
>>>>>>>> class RecursiveBase : public BaseType
>>>>>>>> {
>>>>>>>> public:
>>>>>>>> virtual void SomeFunc()
>>>>>>>> {
>>>>>>>> // prevent optimizer to remove the function
>>>>>>>> global_var++;
>>>>>>>> }
>>>>>>>> };
>>>>>>>>
>>>>>>>> class Derived : public RecursiveBase<Base>, public Base2, public
>>>>>>>> Base3
>>>>>>>> {
>>>>>>>> public:
>>>>>>>> Derived() = default;
>>>>>>>>
>>>>>>>> void Func() override {}
>>>>>>>> };
>>>>>>>>
>>>>>>>> I can get a CXCursor_CXXBaseSpecifier cursor as children of the
>>>>>>>> "Derived" cursor, but not RecursiveBase. How can I find out
>>>>>>>> references
>>>>>>>> to all base classes including templates?
>>>>>>>>
>>>>>>>> Thanks.
>>>>>>>>
>>>>>>>> Nestal
>>>>>>>> _______________________________________________
>>>>>>>> cfe-dev mailing list
>>>>>>>> cfe-dev at lists.llvm.org
>>>>>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>
>>>> _______________________________________________
>>>> cfe-dev mailing list
>>>> cfe-dev at lists.llvm.org
>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> cfe-dev mailing list
>>> cfe-dev at lists.llvm.org
>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>
>
More information about the cfe-dev
mailing list