[cfe-dev] LangOpts && "Unexpected diagnostic outside source file processing" failed.

[Eli Friedman]

On Thu, Sep 16, 2010 at 2:27 PM, Alberto Magni
<alberto.magni86 at gmail.com> wrote:
> Hi everybody,
>
> I am new to clang and I am trying to learn it going through this tutorial:
> http://www.cs.rpi.edu/~laprej/clang.html
> I have a very basic problem though.  After some work I ended up to this
> piece of code:
>
> int main(int argc, char** argv)
> {
>     FileManager* fileManager = new FileManager();
>     LangOptions* languageOptions = new LangOptions();
>     languageOptions->BCPLComment=1;
>     languageOptions->C99=1;
>     DiagnosticOptions* diagnosticOptions=new DiagnosticOptions();
>     llvm::raw_os_ostream os(cout);
>     TextDiagnosticPrinter* diagnosticClient=new
> TextDiagnosticPrinter(os,*diagnosticOptions,true);
>     Diagnostic* diagnostic = new Diagnostic(diagnosticClient);
>     SourceManager* sourceManager= new SourceManager(*diagnostic);
>     HeaderSearch* headerSearch = new HeaderSearch(*fileManager);
>     TargetOptions targetOptions;
>     targetOptions.Triple=LLVM_HOSTTRIPLE;
>     TargetInfo *targetInfo = TargetInfo::CreateTargetInfo (*diagnostic,
> targetOptions);
>     Preprocessor* preprocessor = new Preprocessor(*diagnostic,
> *languageOptions, *targetInfo, *sourceManager, *headerSearch);
>     const FileEntry* fileEntry=fileManager->getFile("test.c");
>     sourceManager->createMainFileID(fileEntry);
>     preprocessor->EnterMainSourceFile();
>     Token token;
>     do
>     {
>         preprocessor->Lex(token);
>         if(diagnostic->hasErrorOccurred())
>         {
>             break;
>         }
>         preprocessor->DumpToken(token);
>         std::cerr << std::endl;
>     }
>     while(token.isNot(tok::eof));
>     diagnosticClient->EndSourceFile();
>     return 0;
> }
>
> This works well with input files with not errors or no warnings.
>
> Then I give as input this very minimalistic file (test.c):
>
> int main() {
>   /* Nested /* comments */
> }
>
> The parsing of this code should produce a warning for the presence of the
> nested comment, but instead I get this output:
>
> int 'int'
> identifier 'main'
> l_paren '('
> r_paren ')'
> l_brace '{'
> clangExample: TextDiagnosticPrinter.cpp:298: void
> clang::TextDiagnosticPrinter::EmitCaretDiagnostic(clang::SourceLocation,
> clang::CharSourceRange*, unsigned int, const clang::SourceManager&, const
> clang::FixItHint*, unsigned int, unsigned int, unsigned int, unsigned int,
> unsigned int): Assertion `LangOpts && "Unexpected diagnostic outside source
> file processing"' failed.
>
> The problem is that the preprocessor tries to output the diagnostic message
> outside the right context. I also tried to call the
> diagnosticClient->BeginSourceFile function before the parsing of the file
> but no warning is displayed either, the parsing is stopped with no messages
> at all.
>
> I also tried the CompilerInstance/CompilerInvocation approach with the same
> result.
>
> How can I fix this issue? Where am I wrong ?
>
> Any help is greatly appreciated.

Your initialization code is probably wrong somehow, but these sorts of
errors can be difficult to precisely locate.  Please use use the
frontend infrastructure like the example in
examples/clang-interpreter/ does, and inherit from
PreprocessorFrontendAction to build your own action similar to
DumpRawTokensAction in lib/Frontend/FrontendActions.cpp.

-Eli