[cfe-dev] Return type of statement

[Alexei Svitkine]

Oops, this meant to be a reply to all:

I'm attaching a sample program that demonstrates the issue.

The program is not trying to parse anything complicated... only:

int main(void){int i=0;i+=10;return 0;}

And trying to get the type of "i+=10". However, as I've mentioned, it
instead crashes when calling  E->getType().getAsString().

But as Steve pointed out to me, using clang on the command line with
ast-print and -ast-dump on that little program works correctly, and
apparently that option does end up calling getAsString().

So I'm wondering if I'm using the API incorrectly in some way... can
anyone glance over my code and possibly give me a hint of what I'm
doing differently than how ast-print/ast-dump works that would cause
such a crash?

-Alexei

On Tue, Jan 6, 2009 at 4:50 PM, steve naroff <snaroff at apple.com> wrote:
>
> On Jan 6, 2009, at 3:36 PM, Alexei Svitkine wrote:
>
>> Thanks for info.
>>
>> I'm now getting a crash in getAsString() on the Expr's type:
>>
>> if (clang::Expr *E = dyn_cast<clang::Expr>(S)) {
>>  std::cout << "Type: '" << E->getType().getAsString() << "'\n";
>> }
>>
>> GDB prints:
>>
>> Program received signal EXC_BAD_ACCESS, Could not access memory.
>> Reason: KERN_INVALID_ADDRESS at address: 0xc000000f
>> 0x00072d8a in clang::QualType::getAsStringInternal (this=0xbffff758,
>> S=@0xbffff754) at Type.cpp:894
>> 894       getTypePtr()->getAsStringInternal(S);
>> (gdb) bt
>> #0  0x00072d8a in clang::QualType::getAsStringInternal
>> (this=0xbffff758, S=@0xbffff754) at Type.cpp:894
>> #1  0x000050a8 in clang::QualType::getAsString (this=0xbffff758) at
>> Type.h:168
>>
>> Am I doing something wrong, or is this a bug I stumbled upon?
>>
>
> Hi Alexei,
>
> It's hard to say without seeing the code being analyzed.
>
> The ObjC rewriter uses the "getAsString()" API fairly extensively (so if
> there's a bug, it's not easy to diagnose without seeing the source).
>
>> Also, is there some better way to ask questions I encounter, rather
>> than emailing each one? Like some kind of irc chat? (I joined #llvm
>> but there didn't seem to be any clang discussion going on there...)
>>
>
> I'm not aware of any public IRC chat for clang. I believe the llvm IRC is
> fine for clang related stuff. In this case, however, email works fine. You
> could also submit a bugzilla.
>
> snaroff
>
>> Or is bombarding this list with questions the way to go? :P
>
>
>> -Alexei
>>
>> On Mon, Jan 5, 2009 at 11:21 PM, Chris Lattner <clattner at apple.com> wrote:
>>>
>>> On Jan 5, 2009, at 6:31 PM, Alexei Svitkine wrote:
>>>
>>>> Thanks for the pointers.
>>>>
>>>> What's the best way to map from a location in the source to the
>>>> corresponding Stmt (and hence Expr if it is exists)?
>>>
>>> There isn't an efficient way to do it.  You'd have to walk the whole
>>> function body and look at the source ranges that each stmt covers,
>>> stopping
>>> at the smallest one that covers the point of interest.  You could do this
>>> once and build a location -> stmt mapping of course.  This would be
>>> useful
>>> if you do repeated queries (such as having a mouse float over code etc).
>>>
>>> -Chris
>>>
>> _______________________________________________
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>
>

progr
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