http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57227
Bug ID: 57227
Summary: Two function with identical signature but different
calling convention seem to be symbol-encoded by the
same string
Product: gcc
Version: 4.7.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: ondrej.kolacek at centrum dot cz
Consider following snippet in which we specialize Decider template with dummyd
and dummye functions which only differ in calling convention:
int dummyd()
{
return 110;
}
int __attribute__((__stdcall__)) dummye()
{
return 1;
}
template<typename T>
bool Decider(T && )
{
return true;
}
int main()
{
Decider(dummyd);
Decider(dummye);
return 0;
}
trying to compile this results into assembler error:
test2.s: Assembler messages:
test2.s:112: Error: symbol `_Z7DeciderIRFivEEbOT_' is already defined
It seems to me that while g++ knows about dummyd and dummye having different
calling convention, it hands to the assembler two equal symbol names.
I have seen one bug which may be duplicate of this - bug 29328, but
1) the issue may be slightly different, as in my case compiler evidently treats
the two specializations as different types
2) the bug is rotting there for 7 years now so making a new one could stir
things up
g++-4.7 -v -save-temps -g test2.cpp -std=c++11 -m32 -Wall -Wextra
Using built-in specs.
COLLECT_GCC=g++-4.7
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/4.7/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Debian 4.7.2-5'
--with-bugurl=file:///usr/share/doc/gcc-4.7/README.Bugs
--enable-languages=c,c++,go,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-4.7 --enable-shared --enable-linker-build-id
--with-system-zlib --libexecdir=/usr/lib --without-included-gettext
--enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.7
--libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-gnu-unique-object
--enable-plugin --enable-objc-gc --with-arch-32=i586 --with-tune=generic
--enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu
--target=x86_64-linux-gnu
Thread model: posix
gcc version 4.7.2 (Debian 4.7.2-5)
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-g' '-std=c++11' '-m32' '-Wall'
'-Wextra' '-shared-libgcc' '-mtune=generic' '-march=i586'
/usr/lib/gcc/x86_64-linux-gnu/4.7/cc1plus -E -quiet -v -imultilib 32
-imultiarch i386-linux-gnu -D_GNU_SOURCE test2.cpp -m32 -mtune=generic
-march=i586 -std=c++11 -Wall -Wextra -g -fworking-directory -fpch-preprocess -o
test2.ii
ignoring nonexistent directory "/usr/local/include/i386-linux-gnu"
ignoring nonexistent directory
"/usr/lib/gcc/x86_64-linux-gnu/4.7/../../../../x86_64-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/include/c++/4.7
/usr/include/c++/4.7/x86_64-linux-gnu/32
/usr/include/c++/4.7/backward
/usr/lib/gcc/x86_64-linux-gnu/4.7/include
/usr/local/include
/usr/lib/gcc/x86_64-linux-gnu/4.7/include-fixed
/usr/include/i386-linux-gnu
/usr/include
End of search list.
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-g' '-std=c++11' '-m32' '-Wall'
'-Wextra' '-shared-libgcc' '-mtune=generic' '-march=i586'
/usr/lib/gcc/x86_64-linux-gnu/4.7/cc1plus -fpreprocessed test2.ii -quiet
-dumpbase test2.cpp -m32 -mtune=generic -march=i586 -auxbase test2 -g -Wall
-Wextra -std=c++11 -version -o test2.s
GNU C++ (Debian 4.7.2-5) version 4.7.2 (x86_64-linux-gnu)
compiled by GNU C version 4.7.2, GMP version 5.0.5, MPFR version
3.1.0-p10, MPC version 0.9
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
GNU C++ (Debian 4.7.2-5) version 4.7.2 (x86_64-linux-gnu)
compiled by GNU C version 4.7.2, GMP version 5.0.5, MPFR version
3.1.0-p10, MPC version 0.9
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 66d178dd81da8c975e003e06d9f5e782
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-g' '-std=c++11' '-m32' '-Wall'
'-Wextra' '-shared-libgcc' '-mtune=generic' '-march=i586'
as -v --32 -o test2.o test2.s
GNU assembler version 2.22 (x86_64-linux-gnu) using BFD version (GNU Binutils
for Debian) 2.22
test2.s: Assembler messages:
test2.s:112: Error: symbol `_Z7DeciderIRFivEEbOT_' is already defined
[kolaceko@lce:~/proj/2/avg/mk]$
