[Bug go/60995] New: gccgo ignores .a files with "/SYM64/" symbol table

[Bug go/60995] New: gccgo ignores .a files with "/SYM64/" symbol table

[vogt at linux dot vnet.ibm.com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60995

            Bug ID: 60995
           Summary: gccgo ignores .a files with "/SYM64/" symbol table
           Product: gcc
           Version: 4.10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: go
          Assignee: ian at airs dot com
          Reporter: vogt at linux dot vnet.ibm.com

On platforms where ar generates .a files with a "/SYM64/" symbol table (e.g.
s390x), gccgo cannot extract Go export data from such files.  This is because
import-archive.cc:Archive_file::interpret_header() does not recognize the
special file name "/SYM64/         " and treats it as an extended name and
fails with two error messages:

  error: .../libfoo.a: bad extended name index at 8
  error: .../libfoo.a exists but does not contain any Go export data

This is easy to fix by recognizing "/SYM64/<9*space>" as a symbol table by
inserting something like this before the final "else" in interpret_header():

>  else if (hdr->ar_name[1] == 'S' && hdr->ar_name[2] == 'Y'
>	   && hdr->ar_name[3] == 'M' && hdr->ar_name[4] == '6'
>	   && hdr->ar_name[5] == '4' && hdr->ar_name[6] == '/'
>	   && hdr->ar_name[7] == ' '
>	  )
>    {
>      // 64-bit symbol table.
>      pname->clear();
>    }

Note:  Same problem as this one:
http://code.google.com/p/go/issues/detail?id=6383
>From gcc-bugs-return-450095-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Tue Apr 29 07:20:23 2014
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Subject: [Bug c++/60994] gcc does not recognize hidden/shadowed enumeration as valid nested-name-specifier
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60994

--- Comment #2 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
(In reply to Markus Trippelsdorf from comment #1)
> Implicit enum to int conversion is not provided for a scoped enumeration.

That said it is strange that gcc also rejects a plain enum:

markus@x4 /tmp % cat foo.cpp
enum A
{
  n = 3
};

int
foo()
{
  int A;
  return A::n;
}

markus@x4 /tmp % g++ -c -std=c++11 -O3 foo.cpp
foo.cpp: In function ‘int foo()’:
foo.cpp:10:10: error: ‘A’ is not a class, namespace, or enumeration
   return A::n;
          ^
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From: "momchil.velikov at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/60994] gcc does not recognize hidden/shadowed enumeration as valid nested-name-specifier
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id`994

--- Comment #3 from Momchil Velikov <momchil.velikov at gmail dot com> ---
(In reply to Markus Trippelsdorf from comment #1)
> Implicit enum to int conversion is not provided for a scoped enumeration.

This is not the reported error.

In fact, the correct output of the compiler would be to report the invalid
implicit conversion. It does not.

With explicit conversion to int, the compiler still gives an error, but the
error message is not helpful and obscures the cause of the problem, i.e.,
compiling this:

enum struct A
{
  n = 3
};

int
foo()
{
  int A;
  return int(A::n);
}

results in:


b.cc: In function 'int foo()':
b.cc:10:10: error: expected primary-expression before 'int'
   return int(A::n);
          ^
b.cc:10:10: error: expected ';' before 'int'
b.cc:10:10: error: expected primary-expression before 'int'

[Bug go/60995] gccgo ignores .a files with "/SYM64/" symbol table

[ian at airs dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60995

Ian Lance Taylor <ian at airs dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |FIXED

--- Comment #1 from Ian Lance Taylor <ian at airs dot com> ---
Fixed by https://codereview.appspot.com/154800044 .