llvm dev - Sep 2019 - DWARF-5 Supported languages Tags C++03, C++11,C++14

Hello Everyone,

I'm working on providing support for New Language Tags, prescribed in
DWARF-5.
DW_LANG_C_plus_plus_03
DW_LANG_C_plus_plus_11
DW_LANG_C_plus_plus_14

While, C++11 and C++14, is defined and can be emitted by Frontend.
"include/clang/Basci/LangStandard.h"
CPlusPlus = (1 << 5),
CPlusPlus11 = (1 << 6),
CPlusPlus14 = (1 << 7),
CPlusPlus17 = (1 << 8),
 CPlusPlus2a = (1 << 9),

Currently CLANG emits "DW_LANG_C_plus_plus" which in DWARF suggests
ISO
C++98, regardless of the -std=... specified in commandline.
Also in file  "include/clang/Basci/LangStandards.def"  CLANG has
aliased
c++98 and c++03.
// C++ modes
 LANGSTANDARD(cxx98, "c++98",
              CXX, "ISO C++ 1998 with amendments",
              LineComment | CPlusPlus | Digraphs)
 LANGSTANDARD_ALIAS(cxx98, "c++03")

So, my query is that since, c++98 and c++03 is mostly same assuming CLANG
Frontend.
Should we also support DW_LANG_C_plus_plus_03 ? for -std=c++03 in Frontend
or let it remain alias of c++98.

LLVM AsmPrinters has already code for supporting these new DWARF-5 Language
Tags.
So, If we decide not to go with DW_LANG_C_plus_plus_03, we'll have to
remove it's reference from llvm, since frontend won't emit it at all.

Thanks!
Sourabh Singh Tomar
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It's OK if LLVM supports things Clang does not.

What does GCC do with the language attribute in different C++
versions? How does LLDB and GDB handle different C++ language versions
specified this way?

On Fri, Sep 13, 2019 at 12:25 AM Sourabh Singh Tomar via llvm-dev
<llvm-dev at lists.llvm.org> wrote:
>
> Hello Everyone,
>
> I'm working on providing support for New Language Tags, prescribed in
DWARF-5.
> DW_LANG_C_plus_plus_03
> DW_LANG_C_plus_plus_11
> DW_LANG_C_plus_plus_14
>
> While, C++11 and C++14, is defined and can be emitted by Frontend.
> "include/clang/Basci/LangStandard.h"
> CPlusPlus = (1 << 5),
> CPlusPlus11 = (1 << 6),
> CPlusPlus14 = (1 << 7),
> CPlusPlus17 = (1 << 8),
>  CPlusPlus2a = (1 << 9),
>
> Currently CLANG emits "DW_LANG_C_plus_plus" which in DWARF
suggests ISO C++98, regardless of the -std=... specified in commandline.
> Also in file  "include/clang/Basci/LangStandards.def"  CLANG has
aliased c++98 and c++03.
> // C++ modes
>  LANGSTANDARD(cxx98, "c++98",
>               CXX, "ISO C++ 1998 with amendments",
>               LineComment | CPlusPlus | Digraphs)
>  LANGSTANDARD_ALIAS(cxx98, "c++03")
>
> So, my query is that since, c++98 and c++03 is mostly same assuming CLANG
Frontend.
> Should we also support DW_LANG_C_plus_plus_03 ? for -std=c++03 in Frontend
or let it remain alias of c++98.
>
> LLVM AsmPrinters has already code for supporting these new DWARF-5 Language
Tags.
> So, If we decide not to go with DW_LANG_C_plus_plus_03, we'll have to
remove it's reference from llvm, since frontend won't emit it at all.
>
> Thanks!
> Sourabh Singh Tomar
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev

> On Sep 13, 2019, at 11:07 AM, David Blaikie <dblaikie at gmail.com>
wrote:
> 
> It's OK if LLVM supports things Clang does not.
> 
> What does GCC do with the language attribute in different C++
> versions? How does LLDB and GDB handle different C++ language versions
> specified this way?
LLDB should be doing the right thing; it knows that all of these are C++. It
will ignore the language version for initializing the expression evaluator with
that version though, since the expression evaluator is global for the entire
program and there is no guarantee that all TUs use the same dialect (also it
uses Objective-C++ as the language, always).

-- adrian
> 
> On Fri, Sep 13, 2019 at 12:25 AM Sourabh Singh Tomar via llvm-dev
> <llvm-dev at lists.llvm.org> wrote:
>> 
>> Hello Everyone,
>> 
>> I'm working on providing support for New Language Tags, prescribed
in DWARF-5.
>> DW_LANG_C_plus_plus_03
>> DW_LANG_C_plus_plus_11
>> DW_LANG_C_plus_plus_14
>> 
>> While, C++11 and C++14, is defined and can be emitted by Frontend.
>> "include/clang/Basci/LangStandard.h"
>> CPlusPlus = (1 << 5),
>> CPlusPlus11 = (1 << 6),
>> CPlusPlus14 = (1 << 7),
>> CPlusPlus17 = (1 << 8),
>> CPlusPlus2a = (1 << 9),
>> 
>> Currently CLANG emits "DW_LANG_C_plus_plus" which in DWARF
suggests ISO C++98, regardless of the -std=... specified in commandline.
>> Also in file  "include/clang/Basci/LangStandards.def"  CLANG
has aliased c++98 and c++03.
>> // C++ modes
>> LANGSTANDARD(cxx98, "c++98",
>>              CXX, "ISO C++ 1998 with amendments",
>>              LineComment | CPlusPlus | Digraphs)
>> LANGSTANDARD_ALIAS(cxx98, "c++03")
>> 
>> So, my query is that since, c++98 and c++03 is mostly same assuming
CLANG Frontend.
>> Should we also support DW_LANG_C_plus_plus_03 ? for -std=c++03 in
Frontend or let it remain alias of c++98.
>> 
>> LLVM AsmPrinters has already code for supporting these new DWARF-5
Language Tags.
>> So, If we decide not to go with DW_LANG_C_plus_plus_03, we'll have
to remove it's reference from llvm, since frontend won't emit it at all.
>> 
>> Thanks!
>> Sourabh Singh Tomar
>> 
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev