Templates

[Erez Louidor Lior]

I've found 2 bugs using templates.

1.

Egcs doesn't instantiate const static variable arrays. For example:

#include <iostream>

template <class T>
class A{
public:
  static const int l[5];
};

template<class T>
const int A<T>::l[5] = {1, 2, 3, 4, 5};

int main(){
  cout << A<int>::l[1];
}

#include <iostream>

template <class T>
class A{
public:
  static const int l[5];
};

eg++ -I /usr/local/egcs/include/g++-2/ static-array.cc
/tmp/ccb2YaIs.o: In function `main':
/tmp/ccb2YaIs.o(.text+0x4): undefined reference to `A<int>::l'
collect2: ld returned 1 exit status

Removing the const in l's declaration and definition solves the problem.

2.  There is an instantiation problem in the template repository.
When using -frepo, in the compilation stage, te compiler only emits
symbols
that require instantiation from non-template code. If instantiating
these symbols will
require futher symbols to be instantiated these required symbols are
not
emitted into the
repository. For example:
#include <iostream>

template <class T>
class foo{
public:
  void g();
  void h();
};

template <class T>
void foo<T>::g() {
  h();
}

template <class T>
void foo<T>::h() {
  cout << "foo::h called" << endl;
}

int main() {
  foo<int> f;
  f.g();
}

Here, the instantiation of g will require h to be instantiated as well,
but
the compiler only emits to the repository, that g needs to be
instantiated.

eg++ -I /usr/local/egcs/include/g++-2/ -frepo -c foo.cc

foo.rpo: (after compilation, before link)
M foo.cc
D /home/Erez/C++/compilers/egcs
A '-I' '/usr/local/egcs/include/g++-2/' '-frepo' '-c'
O g__t3foo1Zi

eg++ -frepo foo.o
collect: recompiling foo.cc
collect: relinking
foo.o: In function `foo<int>::g(void)':
foo.o(.text+0x25): undefined reference to `foo<int>::h(void)'
collect2: ld returned 1 exit status

foo.rpo: (after linking)
M foo.cc
D /home/Erez/C++/compilers/egcs
A '-I' '/usr/local/egcs/include/g++-2/' '-frepo' '-c'
O h__t3foo1Zi
C g__t3foo1Zi

I was using egcs on linux. Also I was using binutils 2.9.1 that were
built in the same
directory I compiled egcs, using egcs' makefile.

eg++ -v produced:
Reading specs from
/usr/local/egcs-19981005/lib/gcc-lib/i586-pc-linux-gnulibc1/egcs-2.92.13/specs

gcc version egcs-2.92.13 19981005 (gcc2 ss-980609 experimental)
 

    Hope this helps...

    Erez.
-- 
----------------------------------------------------------------------
"The ships hung in the sky in much the same way that bricks don't."
        -- Douglas Adams / The Hitchhiker "Trilogy".
ÂÂ