[PATCH] D25826: [ELF] Show error location for 'undefined symbol' errors

[Eugene Leviant via llvm-commits]

Looks like you're right. There is no error, because DIHelper is a
template and expanded in the place of usage (InputFiles.cpp) after
DWARFDebugLine.h is included
Once you try doing this in regular class, you'll immediately get

error: invalid application of 'sizeof' to an incomplete type
'llvm::DWARFDebugLine'

2016-10-25 21:53 GMT+03:00 Rui Ueyama <ruiu at google.com>:
> I actually didn't see any error when I simply converted it to unique_ptr and
> removed the dtor, so I'm wondering what error you saw. In any case, doesn't
> this work?
>
> diff --git a/ELF/InputFiles.cpp b/ELF/InputFiles.cpp
> index 497f946..01f8be9 100644
> --- a/ELF/InputFiles.cpp
> +++ b/ELF/InputFiles.cpp
> @@ -43,7 +43,7 @@ template <class ELFT>
> DIHelper<ELFT>::DIHelper(elf::InputFile *F) {
>      return;
>
>    DWARFContextInMemory Dwarf(*Obj.get());
> -  DwarfLine = new DWARFDebugLine(&Dwarf.getLineSection().Relocs);
> +  DwarfLine.reset(new DWARFDebugLine(&Dwarf.getLineSection().Relocs));
>    DataExtractor lineData(Dwarf.getLineSection().Data,
>                           ELFT::TargetEndianness == support::little,
>                           ELFT::Is64Bits ? 8 : 4);
> @@ -53,7 +53,7 @@ template <class ELFT>
> DIHelper<ELFT>::DIHelper(elf::InputFile *F) {
>    DwarfLine->getOrParseLineTable(lineData, 0);
>  }
>
> -template <class ELFT> DIHelper<ELFT>::~DIHelper() { delete DwarfLine; }
> +template <class ELFT> DIHelper<ELFT>::~DIHelper() {}
>
>  template <class ELFT> std::string DIHelper<ELFT>::getLineInfo(uintX_t
> Offset) {
>    DILineInfo LineInfo;
> diff --git a/ELF/InputFiles.h b/ELF/InputFiles.h
> index a1a63b8..6c0f5cb 100644
> --- a/ELF/InputFiles.h
> +++ b/ELF/InputFiles.h
> @@ -58,7 +58,7 @@ public:
>    std::string getLineInfo(uintX_t Offset);
>
>  private:
> -  llvm::DWARFDebugLine *DwarfLine = nullptr;
> +  std::unique_ptr<llvm::DWARFDebugLine> DwarfLine;
>  };
>
>  // The root class of input files.
>
> On Tue, Oct 25, 2016 at 11:35 AM, Eugene Leviant <evgeny.leviant at gmail.com>
> wrote:
>>
>> I might not be catching your idea, but if you have the following line
>> in InputFiles.h:
>>
>> std::unique_ptr<DWARFDebugLine> DwarfLine;
>>
>> you will either have to:
>> a) #include <llvm/DebugInfo/DWARFDebugLine.h>
>> or
>> b) std::unique_ptr<DWARFDebugLine, MyDeleter> DwarfLine;
>>
>> This is because std::default_deleter<T> checks sizeof(T) in
>> static_assert (where T is DWARFDebugLine)
>>
>> 2016-10-25 21:26 GMT+03:00 Rui Ueyama <ruiu at google.com>:
>> > On Tue, Oct 25, 2016 at 11:08 AM, Eugene Leviant
>> > <evgeny.leviant at gmail.com>
>> > wrote:
>> >>
>> >> evgeny777 added inline comments.
>> >>
>> >>
>> >> ================
>> >> Comment at: ELF/InputFiles.cpp:56
>> >> +
>> >> +template <class ELFT> DIHelper<ELFT>::~DIHelper() { delete DwarfLine;
>> >> }
>> >> +
>> >> ----------------
>> >> ruiu wrote:
>> >> > Use unique_ptr to remove this dtor.
>> >> It's not possible unless you include DWARFContext.h to InputFiles.h or
>> >> override unique_ptr deleter (second template parameter). Is this
>> >> better?
>> >
>> >
>> > You can have an empty dtor in InputFiles.cpp like `template <class ELFT>
>> > DIHelper<ELFT>::~DIHelper() {}` to write a definition of the dtor in the
>> > cpp
>> > file instead of in the header so that you don't need to include the
>> > DWARFContext.h, can't you?
>
>