[cfe-dev] abort calling getTypeSize

[Dmitri Gribenko]

On Mon, Feb 25, 2013 at 12:46 AM, Peeter Joot <peeter.joot at gmail.com> wrote:
> With the following sample code:
>
> template <class T, size_t extraSize >
> struct OSS_STRUCTURE_PAD_DELTA : public T
> {
>    char pad[ extraSize ] ;
> } ;
>
> and an ast visitor that calls getTypeSize():
>
> bool VisitFieldDecl( FieldDecl * f )
> {
>    RecordDecl * r = f->getParent() ;
>    const QualType & theMembersClassType = m_context.getRecordType( r ) ;
>
>    TypeSourceInfo * pThisFieldSourceInfo = f->getTypeSourceInfo() ;
>
>    TypeLoc thisFieldTypeLoc = pThisFieldSourceInfo->getTypeLoc() ;
>
>    const QualType & thisFieldQualType = thisFieldTypeLoc.getType() ;
>
>    size_t szInBits = m_context.getTypeSize( thisFieldQualType ) ;
>    size_t offsetInBits = m_context.getFieldOffset( f ) ;
>
>    cout
>       << "[" << offsetInBits/8 << "]:\t"
>       << theMembersClassType.getAsString( m_pp ) << "::" <<
> thisFieldQualType.getAsString( m_pp ) << "\t" << f->getNameAsString()
>       << "\tsize: " << szInBits/8 << endl ;
>       ;
>
>    return true ;
> }
>
> I get the following abort:
>
> t.C:5:20: error: unknown type name 'size_t'
> template <class T, size_t extraSize >
>                    ^
> Should not see dependent types
> UNREACHABLE executed at
> /home/hotellnx94/peeterj/clang/sources/llvm/tools/clang/lib/AST/ASTContext.cpp:1322!

It is by design.  You can not compute a sizeof of a dependent type,
and type of 'pad' is value-dependent on 'extraSize'.

Dmitri

-- 
main(i,j){for(i=2;;i++){for(j=2;j<i;j++){if(!(i%j)){j=0;break;}}if
(j){printf("%d\n",i);}}} /*Dmitri Gribenko <gribozavr at gmail.com>*/