[cfe-dev] Combining floatLiteral() Node Matcher with isExpansionInFileMatching() Narrowing Matcher provides unexpected results

Roman Lebedev via cfe-dev cfe-dev at lists.llvm.org
Thu Jan 10 09:25:05 PST 2019


On Thu, Jan 10, 2019 at 10:07 AM FarSight Studios via cfe-dev
<cfe-dev at lists.llvm.org> wrote:
>
> > M_E is a macro and that macro is expanded in your
> >
> > double varX = M_E;
> >
> > line. The expansion is not in math.h. The expansion is in the main file.
> >
> > http://ec2-18-191-7-3.us-east-2.compute.amazonaws.com:10240/z/qRMj-W
>
> Thank you so much for the explanation
You probably want to take a look at clang's PPCallbacks, they would allow you
to be informed when such macro expansion happens.

> > By the way, we have a llvm channel on the cpplang slack
> > (https://cpplang.slack.com). That is a more suitable venue for your
> > questions. This is the development mailing list.
>
> I am sorry that I posted the questions in the wrong place. I didn't know that clang has a slack channel.
This is the right place.
I'm not sure a slack channel is more official place.
There are also IRC channels (e.g. see #llvm).

Roman.

> On Thu, Jan 10, 2019 at 1:01 AM Stephen Kelly via cfe-dev <cfe-dev at lists.llvm.org> wrote:
>>
>> On 09/01/2019 14:15, FarSight Studios via cfe-dev wrote:
>> > Hi,
>> >
>> > Combining floatLiteral() Node Matcher with isExpansionInFileMatching()
>> > Narrowing Matcher provides unexpected results.
>> > The following matcher:
>> > floatLiteral(isExpansionInFileMatching("include/math.h"))
>> > does not matches "M_E" which is defined in "math.h"
>> >
>> > #include <math.h>
>> >
>> > int consts(int n){
>> >      double varX = M_E;
>> >      return varX;
>> > }
>> >
>> > It matches a single unrelated node:
>> > FloatingLiteral 0x562c409bdaa8 </usr/include/math.h:1184:47> 'float'
>> > 0.000000e+00
>> >
>> > Am I doing something wrong?
>>
>>
>> M_E is a macro and that macro is expanded in your
>>
>>   double varX = M_E;
>>
>> line. The expansion is not in math.h. The expansion is in the main file.
>>
>>   http://ec2-18-191-7-3.us-east-2.compute.amazonaws.com:10240/z/qRMj-W
>>
>> By the way, we have a llvm channel on the cpplang slack
>> (https://cpplang.slack.com). That is a more suitable venue for your
>> questions. This is the development mailing list.
>>
>> Thanks,
>>
>> Stephen.
>>
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>
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