[cfe-dev] Downgrading/mapping fatal errors to errors (#include not found)

[Jason Haslam]

> On Jan 5, 2015, at 9:30 AM, Richard Smith <richard at metafoo.co.uk> wrote:
> 
> On Sun, Jan 4, 2015 at 8:15 PM, Jason Haslam <jason.haslam at gmail.com <mailto:jason.haslam at gmail.com>> wrote:
> I wonder if it should continue to report all fatal errors instead of just file-not-found.
> 
> I think it makes sense to report file-not-found repeatedly, because recovery from previous errors is very unlikely to be the cause of later file-not-found errors. For the other fatal cases, that is not the case, so I don't think it makes as much sense to suppress them.
> 
> Also, my patch sort of circumvents the 20 error fatal cutoff. Maybe that’s okay.
> 
> That seems problematic; if essentially-correct code #includes a bunch of headers, but the build fails due to a missing -I path, it seems especially important to respect the error limit.
> 
> I would prefer that we add a flag to diagnostics to indicate if they should be shown even after a fatal error, and then mark err_pp_file_not_found with that flag in the .td file, rather than hard-coding that particular diagnostic.

Okay, I agree. I’ll submit a patch along those lines.

>  
> Jason
> 
> 
>> On Jan 4, 2015, at 2:19 AM, Richard Smith <richard at metafoo.co.uk <mailto:richard at metafoo.co.uk>> wrote:
>> 
>> On Sat, Jan 3, 2015 at 11:15 PM, Jason Haslam <jason.haslam at gmail.com <mailto:jason.haslam at gmail.com>> wrote:
>> This is important to us for the same reasons. In our case we only care about reporting additional file-not-found errors.
>> 
>> Olivier, is this also the case for you, or do you want to see other diagnostics after a missing #include?
>>  
>> The others usually become too noisy. I haven’t found any existing option to control this. We have a local patch to continue reporting file-not-found errors after a fatal error (may be slightly out of date):
>> 
>> --- a/lib/Basic/DiagnosticIDs.cpp
>> +++ b/lib/Basic/DiagnosticIDs.cpp
>> @@ -618,7 +618,7 @@ bool DiagnosticIDs::ProcessDiag(DiagnosticsEngine &Diag) const {
>> 
>>    // If a fatal error has already been emitted, silence all subsequent
>>    // diagnostics.
>> -  if (Diag.FatalErrorOccurred) {
>> +  if (Diag.FatalErrorOccurred && DiagID != diag::err_pp_file_not_found) {
>>      if (DiagLevel >= DiagnosticIDs::Error &&
>>          Diag.Client->IncludeInDiagnosticCounts()) {
>>        ++Diag.NumErrors;
>> 
>> I would love to see an option to control this behavior added to the mainline.
>> 
>> I don't think we need an option for this; it seems reasonable to always report missing #includes, even if we've already hit a fatal error, because a missing include is very unlikely to be caused by a prior missing include (they may have a common cause, but that's OK).
>> 
>> Are there already other flags meant specifically for IDE integration? Maybe this could piggyback on one of them or do something similar?
>> 
>> Jason
>> 
>> 
>> > On Dec 31, 2014, at 4:13 AM, Olivier J. G. <olivier.jg at gmail.com <mailto:olivier.jg at gmail.com>> wrote:
>> >
>> > Hello,
>> >
>> > We've run into a problem using libclang for cpp support in KDevelop: once an #included file is not found, a fatal error is generated which disables all further diagnostics.
>> >
>> > In the context of KDevelop, it is quite important that this be downgraded to a non-fatal error so that further missing includes and issues can be marked in the IDE. It's further desirable that the IDE support is still helpful in the absence of a missing but unimportant #include.
>> >
>> > I've found no way to do this with compiler flags; err_pp_file_not_found has no category so -Wno-fatal-errors=foo can't help (not clear if that's the correct method even if there was a category).
>> >
>> > Is there a way to do this that I missed seeing? Can this diagnostic be re-mapped from fatal to error?
>> >
>> > If there's no existing way to do this, could some interface or compiler flag be added so that err_pp_file_not_found_not_fatal is used instead? What would be the correct place/way to configure this?
>> >
>> > Thanks,
>> >
>> > -Olivier JG
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>> 
>> 
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