[Bug c++/36567] New: Cannot use std::tr1::tie() with unordered_map<> of std::vector<>

[Bug c++/36567] New: Cannot use std::tr1::tie() with unordered_map<> of std::vector<>

[dfeathers at omnitrol dot com]

DESCRIPTION

The following code compiles on Intel without issue with gcc-4.1.3 and gcc-4.2,
but fails at LINE=29 on cross-compile with ppc_85xx-gcc-4.0:

$ cat -n Foo.cc
    1        2    #include <tr1/tuple>
    3    #include <tr1/unordered_map>
    4    #include <vector>
    5    #include <string>
    6        7    typedef std::vector<int> IntVector;
    8    typedef std::tr1::unordered_map<std::string, IntVector,
std::tr1::hash<std::string> > VectorMap;
    9       10    class Foo
   11    {
   12    public:
   13        Foo(VectorMap& map) : map_(map) {}
   14        void insert(std::string s, int value);
   15       16    private:
   17        VectorMap&     map_;
   18    };
   19       20    void Foo::insert(std::string s, int value)
   21    {
   22        bool vector_exists = true;
   23       24        VectorMap::iterator i = map_.find(s);
   25        if (i == map_.end())
   26        {
   27            IntVector v;
   28            std::pair<std::string, IntVector> p(s, v);
   29            std::tr1::tie(i, vector_exists) = map_.insert(p);
   30        }
   31       32        if (!vector_exists)
   33        {
   34            return;
   35        }
   36       37        (*i).second.push_back(value);
   38    }
   39   
$ ppc_85xx-g++ -v -save-temps -c Foo.cc
Using built-in specs.
Target: powerpc-linux
Configured with:
/opt/eldk/build/ppc-2006-01-11/work/usr/src/denx/BUILD/crosstool-0.35/build/gcc-4.0.0-glibc-2.3.5-eldk/powerpc-linux/gcc-4.0.0/configure
--target=powerpc-linux --host=i686-host_pc-linux-gnu
--prefix=/var/tmp/eldk.BjN6Wo/usr/crosstool/gcc-4.0.0-glibc-2.3.5-eldk/powerpc-linux
--with-headers=/var/tmp/eldk.BjN6Wo/usr/crosstool/gcc-4.0.0-glibc-2.3.5-eldk/powerpc-linux/powerpc-linux/include
--with-local-prefix=/var/tmp/eldk.BjN6Wo/usr/crosstool/gcc-4.0.0-glibc-2.3.5-eldk/powerpc-linux/powerpc-linux
--disable-nls --enable-threads=posix --enable-symvers=gnu --enable-__cxa_atexit
--enable-languages=c,c++ --enable-shared --enable-c99 --enable-long-long
Thread model: posix
gcc version 4.0.0 (DENX ELDK 4.0 4.0.0)
/opt/exported/ppc/eldk/toolchain/release-4.0/usr/bin/../libexec/gcc/powerpc-linux/4.0.0/cc1plus
-E -quiet -v -iprefix
/opt/exported/ppc/eldk/toolchain/release-4.0/usr/bin/../lib/gcc/powerpc-linux/4.0.0/
-D_GNU_SOURCE -D__unix__ -D__gnu_linux__ -D__linux__ -Dunix -D__unix -Dlinux
-D__linux -Asystem=linux -Asystem=unix -Asystem=posix Foo.cc -mcpu=8540
-mfloat-gprs=yes -mspe=yes -mabi=spe -fpch-preprocess -o Foo.ii
ignoring nonexistent directory
"/opt/exported/ppc/eldk/toolchain/release-4.0/usr/lib/gcc/powerpc-linux/4.0.0/../../../../include/c++/4.0.0"
ignoring nonexistent directory
"/opt/exported/ppc/eldk/toolchain/release-4.0/usr/lib/gcc/powerpc-linux/4.0.0/../../../../include/c++/4.0.0/backward"
ignoring nonexistent directory
"/opt/exported/ppc/eldk/toolchain/release-4.0/usr/lib/gcc/powerpc-linux/4.0.0/../../../../powerpc-linux/sys-include"
ignoring nonexistent directory
"/opt/exported/ppc/eldk/toolchain/release-4.0/usr/lib/gcc/powerpc-linux/4.0.0/../../../../powerpc-linux/include"
#include "..." search starts here:
#include <...> search starts here:
/opt/exported/ppc/eldk/toolchain/release-4.0/usr/lib/gcc/powerpc-linux/4.0.0/include
/opt/exported/ppc/eldk/toolchain/release-4.0/ppc_85xx/usr/include/c++/4.0.0
/opt/exported/ppc/eldk/toolchain/release-4.0/ppc_85xx/usr/include/c++/4.0.0/powerpc-linux
/opt/exported/ppc/eldk/toolchain/release-4.0/ppc_85xx/usr/include/c++/4.0.0/backward
/opt/exported/ppc/eldk/toolchain/release-4.0/usr/../ppc_85xx/usr/include
End of search list.
/opt/exported/ppc/eldk/toolchain/release-4.0/usr/bin/../libexec/gcc/powerpc-linux/4.0.0/cc1plus
-fpreprocessed Foo.ii -quiet -dumpbase Foo.cc -mcpu=8540 -mfloat-gprs=yes
-mspe=yes -mabi=spe -auxbase Foo -version -o Foo.s
GNU C++ version 4.0.0 (DENX ELDK 4.0 4.0.0) (powerpc-linux)
       compiled by GNU C version 2.96 20000731 (Red Hat Linux 7.3 2.96-113).
GGC heuristics: --param ggc-min-expand=81 --param ggc-min-heapsize=96936
/opt/exported/ppc/eldk/toolchain/release-4.0/ppc_85xx/usr/include/c++/4.0.0/tr1/tuple_iterate.h:
In constructor 'std::tr1::tuple<_T1, _T2, std::tr1::_NullClass,
std::tr1::_NullClass, std::tr1::_NullClass, std::tr1::_NullClass,
std::tr1::_NullClass, std::tr1::_NullClass, std::tr1::_NullClass,
std::tr1::_NullClass>::tuple(const std::pair<_U1, _U2>&) [with _U1 =
Internal::hashtable_iterator<std::pair<const std::string, IntVector>, false,
false>, _U2 = bool, _T1 = Internal::hashtable_iterator<std::pair<const
std::string, IntVector>, false, false>&, _T2 = bool&]':
Foo.cc:29:   instantiated from here
/opt/exported/ppc/eldk/toolchain/release-4.0/ppc_85xx/usr/include/c++/4.0.0/tr1/tuple_iterate.h:58:
error: invalid initialization of reference of type
'Internal::hashtable_iterator<std::pair<const std::string, IntVector>, false,
false>&' from expression of type 'const
Internal::hashtable_iterator<std::pair<const std::string, IntVector>, false,
false>'
/opt/exported/ppc/eldk/toolchain/release-4.0/ppc_85xx/usr/include/c++/4.0.0/tr1/tuple_iterate.h:58:
error: invalid initialization of reference of type 'bool&' from expression of
type 'const bool'

#-------------------------------------------------------------------------------

WORKAROUND

Replace LINE=29 with lines 30..33 inclusive as shown below.

$ cat -n Foo2.cc
     1
     2  #include <tr1/tuple>
     3  #include <tr1/unordered_map>
     4  #include <vector>
     5  #include <string>
     6
     7  typedef std::vector<int> IntVector;
     8  typedef std::tr1::unordered_map<std::string, IntVector,
std::tr1::hash<std::string> > VectorMap;
     9
    10  class Foo2
    11  {
    12  public:
    13      Foo2(VectorMap& map) : map_(map) {}
    14      void insert(std::string s, int value);
    15
    16  private:
    17      VectorMap&     map_;
    18  };
    19
    20  void Foo2::insert(std::string s, int value)
    21  {
    22      bool vector_exists = true;
    23
    24      VectorMap::iterator i = map_.find(s);
    25      if (i == map_.end())
    26      {
    27          IntVector v;
    28          std::pair<std::string, IntVector> p(s, v);
    29  //      std::tr1::tie(i, vector_exists) = map_.insert(p); // broken
    30          std::pair<VectorMap::iterator, bool> result(map_.end(), false);
    31          result = map_.insert(p);
    32          i = result.first;
    33          vector_exists = result.second;
    34      }
    35
    36      if (!vector_exists)
    37      {
    38          return;
    39      }
    40
    41      (*i).second.push_back(value);
    42  }
    43


-- 
           Summary: Cannot use std::tr1::tie() with unordered_map<> of
                    std::vector<>
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: dfeathers at omnitrol dot com
 GCC build triplet: i686-host_pc-linux-gnu
  GCC host triplet: i686-host_pc-linux-gnu
GCC target triplet: powerpc-unknown-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36567

[Bug c++/36567] Cannot use std::tr1::tie() with unordered_map<> of std::vector<>

[dfeathers at omnitrol dot com]

------- Comment #1 from dfeathers at omnitrol dot com  2008-06-18 19:17 -------
Created an attachment (id=15779)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=15779&action=view)
Preprocessed .ii file that reproduces the compilation error

1) uncompress as follows

$ gzip -d Foo.ii.gz # giving Foo.ii


2) compile as follows (with gcc-4.0.0 cross compiler):

$ ppc_85xx-g++ Foo.ii


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36567

[Bug c++/36567] Cannot use std::tr1::tie() with unordered_map<> of std::vector<>

[paolo dot carlini at oracle dot com]

------- Comment #2 from paolo dot carlini at oracle dot com  2008-06-18 22:13 -------
I do not understand: do you have any evidence that current, maintained,
branches of GCC (ie 4_2, 4_3) have problems here? I do not. Because certainly
people are not going to do anything on 4_0, and a C++ issue like that, an error
from the C++ front-end, is also extremely unlikely to depend on the target.


-- 

paolo dot carlini at oracle dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36567

[Bug c++/36567] Cannot use std::tr1::tie() with unordered_map<> of std::vector<>

[dfeathers at omnitrol dot com]

------- Comment #3 from dfeathers at omnitrol dot com  2008-07-08 22:35 -------
Subject: Re:  Cannot use std::tr1::tie() with unordered_map<>
 of std::vector<>

Paolo - Sorry for this delayed response.

a) The problem does not exist on gcc 4.2 (Intel), but I do not have a 
4.2 PPC x-compiler - only 4.0. So I cannot confirm a x-compile issue in 4.2.

b) It would be very helpful if you would tell me GCC's support policy. 
i.e. How far back from the latest release will bug reports be 
considered? In this case, I've reported a bug only three minor releases 
back of the latest [4.2 at the time] and you seem to be saying "too old".

c) I identified the problem as "C++", but more correctly it is an STL 
problem.

d) If and when I can reproduce the problem in a current release, I'll 
let you know.

Thanks,
... Dave


paolo dot carlini at oracle dot com wrote:
>
>
> ------- Comment #2 from paolo dot carlini at oracle dot com  
> 2008-06-18 22:13 -------
> I do not understand: do you have any evidence that current, maintained,
> branches of GCC (ie 4_2, 4_3) have problems here? I do not. Because 
> certainly
> people are not going to do anything on 4_0, and a C++ issue like that, 
> an error
> from the C++ front-end, is also extremely unlikely to depend on the 
> target.
>
>
> --
>
> paolo dot carlini at oracle dot com changed:
>
>            What    |Removed                     |Added
> ----------------------------------------------------------------------------
>              Status|UNCONFIRMED                 |WAITING
>
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36567
>
> ------- You are receiving this mail because: -------
> You reported the bug, or are watching the reporter.
>


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36567

[Bug c++/36567] Cannot use std::tr1::tie() with unordered_map<> of std::vector<>

[paolo dot carlini at oracle dot com]

------- Comment #4 from paolo dot carlini at oracle dot com  2008-07-09 11:18 -------
(In reply to comment #3)
> a) The problem does not exist on gcc 4.2 (Intel), but I do not have a 
> 4.2 PPC x-compiler - only 4.0. So I cannot confirm a x-compile issue in 4.2.

Ok.

> b) It would be very helpful if you would tell me GCC's support policy. 
> i.e. How far back from the latest release will bug reports be 
> considered? In this case, I've reported a bug only three minor releases 
> back of the latest [4.2 at the time] and you seem to be saying "too old".

Well, it's easy, we just closed 4_1-branch, 4_0-branch has been closed a lot of
time ago. That means, you can certainly find somehow a volunteer working on the
release branch you care about, but since the branch is closed, the fix will not
appear in any further official release from the branch.

> c) I identified the problem as "C++", but more correctly it is an STL 
> problem.

Wrongly. There is no "STL" mention in the C++ Standard in force (C++98 + TC1),
"STL" is a legacy acronym dating back to the HP / SGI times. The problem would
be, in case, libstdc++, that this our (GNU) implementation of the C++ Standard
Library.

> d) If and when I can reproduce the problem in a current release, I'll 
> let you know.

Ok. For now, I'm going to close this one, for lack, to date, of compelling
evidence. Thanks again.


-- 

paolo dot carlini at oracle dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |RESOLVED
         Resolution|                            |INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36567