[Bug c++/55958] New: vtable hidden when compiling with -fvisibility-ms-compat
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55958
Bug #: 55958
Summary: vtable hidden when compiling with
-fvisibility-ms-compat
Classification: Unclassified
Product: gcc
Version: 4.7.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: g...@gonsoe.com
Created attachment 29153
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=29153
so1.h, so1.cxx, main.cxx, Makefile + compiler --save-temp files. Build with
'make main'
% gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/i686-linux-gnu/4.7/lto-wrapper
Target: i686-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro
4.7.2-2ubuntu1' --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 --enable-targets=all --disable-werror
--with-arch-32=i686 --with-tune=generic --enable-checking=release
--build=i686-linux-gnu --host=i686-linux-gnu --target=i686-linux-gnu
Thread model: posix
gcc version 4.7.2 (Ubuntu/Linaro 4.7.2-2ubuntu1)
The vtable for a class with a virtual member function is HIDDEN when source
file is compiled with -fvisibility-ms-compat. If a shared library is created
from the object file, then clients of the shared library cannot construct
objects of the class without getting an undefined symbol for the vtable.
% cat so1.h
#ifdef SO1_SOURCE
# define EXPORT __attribute ((visibility("default")))
#else
# define EXPORT
#endif
class SO1
{
public:
EXPORT virtual void foo();
};
% cat so1.cxx
#define SO1_SOURCE
#include "so1.h"
void SO1::foo() {}
% g++ -c so1.cxx -fvisibility-ms-compat
% eu-readelf -s so1.o | c++filt|grep SO1
14: 5 FUNCGLOBAL DEFAULT4 SO1::foo()
15: 12 OBJECT WEAK HIDDEN 7 vtable for SO1
16: 8 OBJECT WEAK DEFAULT9 typeinfo for SO1
18: 5 OBJECT WEAK DEFAULT 11 typeinfo name for SO1
% g++ -shared -o libso1.so so1.o
% cat main.cxx
#include "so1.h"
int main()
{
SO1 so1;
return 0;
}
% g++ main.cxx -L. -lso1
/tmp/ccLfT7tK.o: In function `SO1::SO1()':
main.cxx:(.text._ZN3SO1C2Ev[_ZN3SO1C5Ev]+0x8): undefined reference to `vtable
for SO1'
collect2: error: ld returned 1 exit status
[Bug c++/55958] vtable hidden when compiling with -fvisibility-ms-compat
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55958 --- Comment #2 from Soren Soe 2013-01-13 00:16:11 UTC --- Unfortunately this is a both a Linux and Windows project. I would like to reuse the windows export macros, have gcc default to -fvisibility-ms-compat so that everything except typeinfo and supposedly vtable is marked hidden, then explicitly export only what needs to be exported. My understanding is that -fvisibility-ms-compat is exactly for that purpose, but the hidden vtable is not consistent with windows.
[Bug libstdc++/69116] New: compile error when including valarray
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69116
Bug ID: 69116
Summary: compile error when including valarray
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: gnu at gonsoe dot com
Target Milestone: ---
The following code does not compile with gcc4.8.4 or gcc5.2.1. I have access
to an older 4.8.0 compiler where the code compiles ok, so this appears to be a
regression.
The inclusion of causes the compile error.
#include
#include
struct x : public std::ostream
{
virtual void flush() = 0;
};
void foo(x& os)
{
os << std::endl;
}
Using built-in specs.
COLLECT_GCC=gcc
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu
4.8.4-2ubuntu1~14.04' --with-bugurl=file:///usr/share/doc/gcc-4.8/README.Bugs
--enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-4.8 --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--with-gxx-include-dir=/usr/include/c++/4.8 --libdir=/usr/lib --enable-nls
--with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug
--enable-libstdcxx-time=yes --enable-gnu-unique-object --disable-libmudflap
--enable-plugin --with-system-zlib --disable-browser-plugin
--enable-java-awt=gtk --enable-gtk-cairo
--with-java-home=/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64/jre --enable-java-home
--with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-4.8-amd64
--with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-4.8-amd64
--with-arch-directory=amd64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar
--enable-objc-gc --enable-multiarch --disable-werror --with-arch-32=i686
--with-abi=m64 --with-multilib-list=m32,m64,mx32 --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 4.8.4 (Ubuntu 4.8.4-2ubuntu1~14.04)
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-c' '-std=c++11' '-mtune=generic'
'-march=x86-64'
/usr/lib/gcc/x86_64-linux-gnu/4.8/cc1plus -E -quiet -v -imultiarch
x86_64-linux-gnu -D_GNU_SOURCE va.cxx -mtune=generic -march=x86-64 -std=c++11
-fpch-preprocess -fstack-protector -Wformat -Wformat-security -o va.ii
ignoring duplicate directory "/usr/include/x86_64-linux-gnu/c++/4.8"
ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu"
ignoring nonexistent directory
"/usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../x86_64-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/include/c++/4.8
/usr/include/x86_64-linux-gnu/c++/4.8
/usr/include/c++/4.8/backward
/usr/lib/gcc/x86_64-linux-gnu/4.8/include
/usr/local/include
/usr/lib/gcc/x86_64-linux-gnu/4.8/include-fixed
/usr/include/x86_64-linux-gnu
/usr/include
End of search list.
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-c' '-std=c++11' '-mtune=generic'
'-march=x86-64'
/usr/lib/gcc/x86_64-linux-gnu/4.8/cc1plus -fpreprocessed va.ii -quiet
-dumpbase va.cxx -mtune=generic -march=x86-64 -auxbase va -std=c++11 -version
-fstack-protector -Wformat -Wformat-security -o va.s
GNU C++ (Ubuntu 4.8.4-2ubuntu1~14.04) version 4.8.4 (x86_64-linux-gnu)
compiled by GNU C version 4.8.4, GMP version 5.1.3, MPFR version
3.1.2-p3, MPC version 1.0.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
GNU C++ (Ubuntu 4.8.4-2ubuntu1~14.04) version 4.8.4 (x86_64-linux-gnu)
compiled by GNU C version 4.8.4, GMP version 5.1.3, MPFR version
3.1.2-p3, MPC version 1.0.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 9cb21c615435621dce26fe5e793192fd
In file included from va.cxx:2:0:
/usr/include/c++/4.8/valarray: In instantiation of ‘class std::valarray’:
va.cxx:10:14: required from here
/usr/include/c++/4.8/valarray:926:5: error: cannot allocate an object of
abstract type ‘x’
valarray<_Tp>::sum() const
^
va.cxx:4:8: note: because the following virtual functions are pure within
‘x’:
struct x : public std::ostream
^
va.cxx:6:16: note: virtual void x::flush()
virtual void flush() = 0;
^
In file included from va.cxx:2:0:
/usr/include/c++/4.8/valarray:1033:5: error: cannot allocate an object of
abstract type ‘x’
valarray<_Tp>::min() const
^
va.cxx:4:8: note: since type ‘x’ has pure virtual functions
struct x : public std::ostream
^
In file included from va.cxx:2:0:
/usr/include/c++/4.8/valarray:1041:5: error: cannot allocate an object of
abstract type ‘x’
valarray<_Tp>::max() const
^
va.cxx:4:8: note: since type ‘x’ has pure virtual function
[Bug middle-end/99689] Initialized local variable becomes uninitialized after use
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99689
Soren Soe changed:
What|Removed |Added
CC||gnu at gonsoe dot com
--- Comment #5 from Soren Soe ---
I've tried all options. Fails only when compiled with -O3.
I looked at assembler code on https://godbolt.org, and it appears that with ARM
gcc9.3 the unsigned int variable is not initialized. The assembler code is
very different if unsigned int is replaced with size_t, or when using -O2, and
appears to show a variable initialized to 0.
void
good()
{
vec v;
v.emplace_back("abc", "def");
v.emplace_back("abc", "def");
v.emplace_back("abc", "def");
v.emplace_back("abc", "def");
v.emplace_back("abc", "def");
size_t m = 0;
for (auto& p : v)
m = std::max(m, p.first.length());
assert(m==3);
}
void
bad()
{
vec v;
v.emplace_back("abc", "def");
v.emplace_back("abc", "def");
v.emplace_back("abc", "def");
v.emplace_back("abc", "def");
v.emplace_back("abc", "def");
unsigned int m = 0;
for (auto& p : v)
m = std::max(m, p.first.length());
assert(m==3);
}
[Bug middle-end/99689] Initialized local variable becomes uninitialized after use
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99689 --- Comment #6 from Soren Soe --- I should maybe mention that the same problem is reproducible using qemu-aarch64 and qemu-aarch64-static on an x86_64 host. % aarch64-linux-gnu-g++ -O3 -static bug.cpp % qemu-aarch64-static ./a.out a.out: bug.cpp:78: void bad(): Assertion `m == 3' failed. qemu: uncaught target signal 6 (Aborted) - core dumped Aborted (core dumped) Works fine with -O2 or the size_t variant I mentioned. % aarch64-linux-gnu-g++ -v Using built-in specs. COLLECT_GCC=aarch64-linux-gnu-g++ COLLECT_LTO_WRAPPER=/usr/lib/gcc-cross/aarch64-linux-gnu/9/lto-wrapper Target: aarch64-linux-gnu Configured with: ../src/configure -v --with-pkgversion='Ubuntu 9.3.0-17ubuntu1~20.04' --with-bugurl=file:///usr/share/doc/gcc-9/README.Bugs --enable-languages=c,ada,c++,go,d,fortran,objc,obj-c++,gm2 --prefix=/usr --with-gcc-major-version-only --program-suffix=-9 --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new --enable-gnu-unique-object --disable-libquadmath --disable-libquadmath-support --enable-plugin --enable-default-pie --with-system-zlib --without-target-system-zlib --enable-libpth-m2 --enable-multiarch --enable-fix-cortex-a53-843419 --disable-werror --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=aarch64-linux-gnu --program-prefix=aarch64-linux-gnu- --includedir=/usr/aarch64-linux-gnu/include Thread model: posix gcc version 9.3.0 (Ubuntu 9.3.0-17ubuntu1~20.04)
