[cfe-dev] Get name of MemberExpr expression

Thu Dec 7 14:47:40 PST 2017

1. Get base: E = MemberExpr->getBase();
2. Clear it from parens and casts (optional): E = E->Ignore*() // various
variants from Expr (I don't know actually if you need this and if so, what
you actually need in your case)
3. Make sure it is DeclRefExpr (via dyn_cast_or_null) and get its
declaration via getDecl / getFoundDecl depending on your needs.

8 Дек 2017 г. 1:15 пользователь "Qiufeng Yu" <qyu4 at ncsu.edu> написал:

> Here is the ast dump for the MemberExpr that I'm interested in.
>
> MemberExpr 0x55deb5e87188 'unsigned int (void)' lvalue .__fetch_builtin_x
> 0x55deb5001b60
> `-OpaqueValueExpr 0x55deb5e87130 'const struct __cuda_builtin_blockIdx_t'
> lvalue
>   `-DeclRefExpr 0x55deb5e870d0 'const struct __cuda_builtin_blockIdx_t'
> lvalue Var 0x55deb5097940 'blockIdx' 'const struct
> __cuda_builtin_blockIdx_t'
>
> MemberExpr 0x55deb5e87388 'unsigned int (void)' lvalue .__fetch_builtin_y
> 0x55deb5001d50
> `-OpaqueValueExpr 0x55deb5e87330 'const struct __cuda_builtin_blockIdx_t'
> lvalue
>   `-DeclRefExpr 0x55deb5e872d0 'const struct __cuda_builtin_blockIdx_t'
> lvalue Var 0x55deb5097940 'blockIdx' 'const struct
> __cuda_builtin_blockIdx_t'
>
> I think the member name should be __fetch_builting_x or __fetch_buildin_y,
> and the base name should be found in a DeclRefExpr.
> The problem is that, all I have is a Stmt pointer Stmt *s, which can be
> casted to MemberExpr *me, then I do if(MemberExpr *me =
> dyn_cast<MemberExpr>(s)) to see if the Stmt is a MemberExpr.
> If yes, how do I cast this *me to OpaqueValueExpr or DeclRefExpr to
> retrieve the actually name in the DeclRefExpr?
>
>
>
> On Thu, Dec 7, 2017 at 2:49 PM, Qiufeng Yu <qyu4 at ncsu.edu> wrote:
>
>> Hi Alexey,
>>
>> As far as checking the base. What's the best way to check if the base is
>> actually "blockIdx"?
>>
>> On Thu, Dec 7, 2017 at 6:19 AM, Alexey Knyshev <alexey.knyshev at gmail.com>
>> wrote:
>>
>>> You should not check RecordDecl in this manner as soon as it MemberExpr
>>> is "composite". I mean you should separately check base & memberDecl.
>>>
>>> According to docs for MeberExpr::getMemberDecl
>>> <https://clang.llvm.org/doxygen/classclang_1_1MemberExpr.html#a66dc522ec5732b5e4a1a90bdfe70919f>
>>> The returned declaration will be a FieldDecl or (in C++) a VarDecl (for
>>>   /// static data members), a CXXMethodDecl, or an EnumConstantDecl.
>>>
>>> 2017-12-07 12:21 GMT+03:00 Qiufeng Yu <qyu4 at ncsu.edu>:
>>>
>>>> I can also use the ASTMatcher to find all MemberExprs, but still can't
>>>> narrow them down to those only called blockIdx.x and blockIdx.y.
>>>> My Matcher is following:
>>>>
>>>> Matcher.addMatcher(memberExpr(hasObjectExpression(hasType(cx
>>>> xRecordDecl(hasName("blockIdx.x"))))));
>>>> Matcher.addMatcher(memberExpr(hasObjectExpression(hasType(cx
>>>> xRecordDecl(hasName("blockIdx.y"))))));
>>>>
>>>> On Thu, Dec 7, 2017 at 3:55 AM, Qiufeng Yu <qyu4 at ncsu.edu> wrote:
>>>>
>>>>> Say the original code is int bx = blockIdx.x, I already found the
>>>>> MemberExpr of this line of code, which is blockIdx.x. But all I have is
>>>>> only this MemberExpr. What I need is the actual string representation of
>>>>> this MemberExpr so that I can perform the string comparison to make sure
>>>>> that this MemberExpr is indeed blockIdx.x, and perform the rewriting
>>>>> process.
>>>>>
>>>>> On Thu, Dec 7, 2017 at 3:48 AM, Alexey Knyshev <
>>>>> alexey.knyshev at gmail.com> wrote:
>>>>>
>>>>>> Hi,
>>>>>> Do you mean finding AST corresponding to MemberExpr or you already
>>>>>> found then and trying to figure out SourceLocation for them?
>>>>>>
>>>>>> Regards, Alexey K
>>>>>>
>>>>>> 2017-12-07 11:40 GMT+03:00 Qiufeng Yu via cfe-dev <
>>>>>> cfe-dev at lists.llvm.org>:
>>>>>>
>>>>>>> Hi all,
>>>>>>>
>>>>>>> I'm new to clang and currently working on a project where I need to
>>>>>>> rewrite some codes in CUDA source file.
>>>>>>>
>>>>>>> For example, if I have the following CUDA code:
>>>>>>>
>>>>>>> int bx = blockIdx.x;
>>>>>>> int by = blockIdx.y;
>>>>>>>
>>>>>>> I want to rewrite the blockIdx and blockIdx.x and blockIdx.y to some
>>>>>>> other code:
>>>>>>> int bx = something else;
>>>>>>> int by = something else;
>>>>>>>
>>>>>>> My problem is that how do I find the MemberExpr blockIdx,x and
>>>>>>> blockIdx.y?
>>>>>>>
>>>>>>> I know how to get the MemberExpr, but I have no clue how to extract
>>>>>>> the name of the MemberExpr in order to know that it is the right MemberExpr
>>>>>>> for me to rewrite.
>>>>>>>
>>>>>>> Any help is appreciated.
>>>>>>>
>>>>>>>
>>>>>>> Patrick
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> cfe-dev mailing list
>>>>>>> cfe-dev at lists.llvm.org
>>>>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> linkedin.com/profile
>>>>>> <https://www.linkedin.com/profile/view?id=AAMAABn6oKQBDhBteiQnWsYm-S9yxT7wQkfWhSw>
>>>>>>
>>>>>> github.com/alexeyknyshev
>>>>>> bitbucket.org/alexeyknyshev
>>>>>>
>>>>>
>>>>>
>>>>
>>>
>>>
>>> --
>>> linkedin.com/profile
>>> <https://www.linkedin.com/profile/view?id=AAMAABn6oKQBDhBteiQnWsYm-S9yxT7wQkfWhSw>
>>>
>>> github.com/alexeyknyshev
>>> bitbucket.org/alexeyknyshev
>>>
>>
>>
>
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