[cfe-dev] Assert in SourceManager::getFileIDSlow()

[Chris Lattner]

On Aug 25, 2009, at 12:30 PM, Alexei Svitkine wrote:

> Some more details:
>
> The input being parsed doesn't have to start with a function
> declaration to trigger this assert.
>
> Also, removing the assert in question makes ccons work correctly. Any
> chance this could be fixed?
>
> (If it could also be added to the clang 1.0 branch, that would be
> really appreciated.)
>
> Thanks! (Patch is attached.)

Alexei, I don't follow why this is safe or how you're triggering it.   
The SourceManager sets up the "Source Location namespace" very  
carefully and "0" is not a valid "offset".  0 is a sentinel that  
indicates a default constructed source location.  I think you need to  
change your client to something like this:


>>      clang::SourceLocation Loc = FD->getTypeSpecStartLoc();
>>      if (Loc.isValid() && SM->isFromMainFile(Loc)) {

-Chris


>
> -Alexei
>
> On Tue, Aug 25, 2009 at 2:00 PM, Alexei
> Svitkine<alexei.svitkine at gmail.com> wrote:
>> Hi,
>>
>> My code is triggering the assert:
>>
>>  assert(SLocOffset && "Invalid FileID");
>>
>> In SourceManager::getFileIDSlow().
>>
>> It happens as a result of calling SM->isFromMainFile(Loc) in some
>> ASTConsumer code that looks like:
>>
>> void HandleTopLevelDecl(clang::DeclGroupRef D) {
>>  for (clang::DeclGroupRef::iterator I = D.begin(), E = D.end(); I ! 
>> = E; ++I) {
>>    if (clang::FunctionDecl *FD = dyn_cast<clang::FunctionDecl>(*I)) {
>>      clang::SourceLocation Loc = FD->getTypeSpecStartLoc();
>>      if (SM->isFromMainFile(Loc)) {
>>        // ...
>>      }
>>    }
>>  }
>> }
>>
>> (The input that is being parsed begins with a function declaration.)
>>
>> I am not sure how old this issue is, but it makes ccons unusable
>> (which is quite a shame, since I hoped ccons could work fine with the
>> clang 1.0 release). Any advice would be appreciated.
>>
>> -Alexei
>>
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