Rejects valid. The following test case fails to link because VFTs are missing.
Based on the C++0x draft (N2800), this program should compile, link and run
successfully.
This appears to be a problem with the GCC implementation of explicit
instantiation
declarations, i.e. extern template.
The source consists of one file with no #include.
> cat a.cpp
template <class T>
struct A {
A();
A(A const &);
A &operator =(A const &);
~A();
virtual int foo();
};
template <class T>
A<T>::A() { }
template <class T>
A<T>::A(A const &) { }
template <class T>
A<T> &A<T>::operator =(A const &) { return *this; }
template <class T>
A<T>::~A() { }
template <class T>
int A<T>::foo(void) {
return 42;
}
// explicit instantiation declaration of a class does not affect the class
itself
// but is an explicit instantiation declaration of each of its members
extern template struct A<int>;
// we provide explicit instantiation definitions of all the members of struct
A<int> here
template A<int>::A();
template A<int>::A(A const &);
template A<int> &A<int>::operator =(A const &);
template A<int>::~A();
template int A<int>::foo();
int main(void) {
A<int> a; // constructor needs to set VFT for `a'
return 0;
}
> /compilers/g++-4.3.2 -std=c++0x -v -c a.cpp -o a.o
Using built-in specs.
Target: powerpc64-unknown-linux-gnu
Configured with: /data/gcc/src/gcc-4.3.2/configure --prefix=/data/gcc
--program-suffix=-4.3.2 --disable-libssp --disable-libgcj
--enable-version-specific-runtime-libs --with-cpu=default32 --enable-secureplt
--with-long-double-128 --enable-shared --enable-__cxa_atexit
--enable-threads=posix --enable-languages=c,c++
Thread model: posix
gcc version 4.3.2 (GCC)
COLLECT_GCC_OPTIONS='-std=c++0x' '-v' '-c' '-o' 'a.o' '-shared-libgcc'
/data/gcc/libexec/gcc/powerpc64-unknown-linux-gnu/4.3.2/cc1plus -quiet -v
-D_GNU_SOURCE -D__unix__ -D__gnu_linux__ -D__linux__ -Asystem=linux
-Asystem=unix -Asystem=posix a.cpp -msecure-plt -quiet -dumpbase a.cpp
-auxbase-strip a.o -std=c++0x -version -o
data/gcc/lib/gcc/powerpc64-unknown-linux-gnu/4.3.2/../../../../powerpc64-unknown-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
/data/gcc/lib/gcc/powerpc64-unknown-linux-gnu/4.3.2/include/c++
/data/gcc/lib/gcc/powerpc64-unknown-linux-gnu/4.3.2/include/c++/powerpc64-unknown-linux-gnu
/data/gcc/lib/gcc/powerpc64-unknown-linux-gnu/4.3.2/include/c++/backward
/usr/local/include
/data/gcc/include
/data/gcc/lib/gcc/powerpc64-unknown-linux-gnu/4.3.2/include
/data/gcc/lib/gcc/powerpc64-unknown-linux-gnu/4.3.2/include-fixed
/usr/include
End of search list.
GNU C++ (GCC) version 4.3.2 (powerpc64-unknown-linux-gnu)
compiled by GNU C version 4.3.2, GMP version 4.1.4, MPFR version 2.2.1.
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: d61d206a8be21ae59ecbfeb94562168a
COLLECT_GCC_OPTIONS='-std=c++0x' '-v' '-c' '-o' 'a.o' '-shared-libgcc'
as -a32 -mppc -many -V -Qy -o a.o
data/gcc/libexec/gcc/powerpc64-unknown-linux-gnu/4.3.2/:/data/gcc/libexec/gcc/powerpc64-unknown-linux-gnu/4.3.2/:/data/gcc/libexec/gcc/powerpc64-unknown-linux-gnu/:/data/gcc/lib/gcc/powerpc64-unknown-linux-gnu/4.3.2/:/data/gcc/lib/gcc/powerpc64-unknown-linux-gnu/
LIBRARY_PATH=/data/gcc/lib/gcc/powerpc64-unknown-linux-gnu/4.3.2/:/data/gcc/lib/gcc/powerpc64-unknown-linux-gnu/4.3.2/../../../../lib/:/lib/../lib/:/usr/lib/../lib/:/data/gcc/lib/gcc/powerpc64-unknown-linux-gnu/4.3.2/../../../:/lib/:/usr/lib/
COLLECT_GCC_OPTIONS='-std=c++0x' '-v' '-c' '-o' 'a.o' '-shared-libgcc'
> /compilers/g++-4.3.2 -std=c++0x -v a.o -o a.out
Using built-in specs.
Target: powerpc64-unknown-linux-gnu
Configured with: /data/gcc/src/gcc-4.3.2/configure --prefix=/data/gcc
--program-suffix=-4.3.2 --disable-libssp --disable-libgcj
--enable-version-specific-runtime-libs --with-cpu=default32 --enable-secureplt
--with-long-double-128 --enable-shared --enable-__cxa_atexit
--enable-threads=posix --enable-languages=c,c++
Thread model: posix
gcc version 4.3.2 (GCC)
COMPILER_PATH=/data/gcc/libexec/gcc/powerpc64-unknown-linux-gnu/4.3.2/:/data/gcc/libexec/gcc/powerpc64-unknown-linux-gnu/4.3.2/:/data/gcc/libexec/gcc/powerpc64-unknown-linux-gnu/:/data/gcc/lib/gcc/powerpc64-unknown-linux-gnu/4.3.2/:/data/gcc/lib/gcc/powerpc64-unknown-linux-gnu/
LIBRARY_PATH=/data/gcc/lib/gcc/powerpc64-unknown-linux-gnu/4.3.2/:/data/gcc/lib/gcc/powerpc64-unknown-linux-gnu/4.3.2/../../../../lib/:/lib/../lib/:/usr/lib/../lib/:/data/gcc/lib/gcc/powerpc64-unknown-linux-gnu/4.3.2/../../../:/lib/:/usr/lib/
COLLECT_GCC_OPTIONS='-std=c++0x' '-v' '-o' 'a.out' '-shared-libgcc'
/data/gcc/libexec/gcc/powerpc64-unknown-linux-gnu/4.3.2/collect2
--eh-frame-hdr -V -Qy -m elf32ppclinux -dynamic-linker /lib/ld.so.1 -o a.out
/usr/lib/../lib/crt1.o /usr/lib/../lib/crti.o
/data/gcc/lib/gcc/powerpc64-unknown-linux-gnu/4.3.2/crtbegin.o
-L/data/gcc/lib/gcc/powerpc64-unknown-linux-gnu/4.3.2
-L/data/gcc/lib/gcc/powerpc64-unknown-linux-gnu/4.3.2/../../../../lib
-L/lib/../lib -L/usr/lib/../lib
-L/data/gcc/lib/gcc/powerpc64-unknown-linux-gnu/4.3.2/../../.. a.o -lstdc++ -lm
-lgcc_s -lgcc -lc -lgcc_s -lgcc
/data/gcc/lib/gcc/powerpc64-unknown-linux-gnu/4.3.2/crtsavres.o
/data/gcc/lib/gcc/powerpc64-unknown-linux-gnu/4.3.2/crtend.o
/usr/lib/../lib/crtn.o
GNU ld version 2.16.91.0.5 20051219 (SUSE Linux)
Supported emulations:
elf32ppclinux
elf32ppc
elf32ppcsim
elf64alpha
alpha
armelf_linux
armelf
hppalinux
elf_i386
i386linux
elf64_ia64
m68kelf
m68klinux
elf64ppc
elf_s390
elf64_s390
elf32_sparc
sparclinux
elf64_sparc
sun4
elf_x86_64
ppcmacosa.o: In function `A<int>::A()':
a.cpp:(.text._ZN1AIiEC2Ev[A<int>::A()]+0x16): undefined reference to `vtable
for A<int>'
a.cpp:(.text._ZN1AIiEC2Ev[A<int>::A()]+0x1a): undefined reference to `vtable
for A<int>'
a.o: In function `A<int>::A()':
a.cpp:(.text._ZN1AIiEC1Ev[A<int>::A()]+0x16): undefined reference to `vtable
for A<int>'
a.cpp:(.text._ZN1AIiEC1Ev[A<int>::A()]+0x1a): undefined reference to `vtable
for A<int>'
a.o: In function `A<int>::A(A<int> const&)':
a.cpp:(.text._ZN1AIiEC2ERKS0_[A<int>::A(A<int> const&)]+0x1a): undefined
reference to `vtable for A<int>'
a.o:a.cpp:(.text._ZN1AIiEC2ERKS0_[A<int>::A(A<int> const&)]+0x1e): more
undefined references to `vtable for A<int>' follow
collect2: ld returned 1 exit status
--
Summary: extern template suppresses VFT but should not
Product: gcc
Version: 4.3.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: hstong at ca dot ibm dot com
GCC build triplet: powerpc64-suse-linux
GCC host triplet: powerpc64-unknown-linux-gnu
GCC target triplet: powerpc64-unknown-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38613
