Compiling with -fvisibility=hidden and -fvisibility-inlines-hidden.
I have a Base class with default visibility which contains two virtual methods,
one inlined and the other not. A Derived class with hidden visibility overrides
the non-inlined method and doesn't touch the inlined one. If the declaration of
the overridden method appears *before* the Derived's virtual destructor then
the object file for Derived weakly exports the Base class's inlined method. But
if the declaration appears *after* Derived's virtual destructor then the object
for Derived doesn't export the Base class's inlined method at all.
Given that I'm compiling with -fvisibility-inlines-hidden I *think* that means
that the Base class's inlined method should never be exported. Even if I'm
wrong about that, surely it should not matter the order in which the Derived
class's methods are declared.
Here's an example which demonstrates the problem:
class __attribute__ ((visibility("default"))) Base
{
public:
Base();
virtual ~Base();
virtual void func() const;
virtual void inlineFunc() {}
};
class Derived : public Base
{
public:
Derived();
void func() const;
virtual ~Derived();
};
void Derived::func() const
{}
Compiled on OSX 10.6.4 with g++ 4.2.1, using the following command:
g++-4.2 -Wall -c -arch x86_64 -fvisibility=hidden -fvisibility-inlines-hidden
-O3 -m64 -isysroot /Developer/SDKs/MacOSX10.6.sdk -mmacosx-version-min=10.6 -o
Derived.o Derived.cpp
Looking at the object file using 'nm -m Derived.o | grep inlineFunc' gives:
0000000000000010 (__TEXT,__textcoal_nt) weak private external
__ZN6Common10inlineFuncEv
0000000000000098 (__TEXT,__eh_frame) weak private external
__ZN6Common10inlineFuncEv.eh
If I move the declaration of Derived::func() so that it comes after ~Derived()
then 'nm -m Derived.o | grep inlineFunc' returns nothing.
I see similar behaviour on GNU/Linux (2.6.30.9-96.fc11.x86_64) using g++ 4.4.1.
Compiling with this command:
g++ -Wall -c -fvisibility=hidden -fvisibility-inlines-hidden -O3 -m64 -o
Derived.o Derived.cpp
and using 'objdump -t Derived.o | grep inlineFunc' to inspect the result gives
this when Derived::func() is declared before ~Derived():
0000000000000000 l d .text._ZN4Base10inlineFuncEv 0000000000000000
.text._ZN4Base10inlineFuncEv
0000000000000000 w F .text._ZN4Base10inlineFuncEv 0000000000000002
.hidden _ZN4Base10inlineFuncEv
and gives nothing when Derived::func() is declared after ~Derived().
--
Summary: -fvisibility-inlines-hidden: Decl order in derived class
affects visibility of inlines in base.
Product: gcc
Version: 4.4.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: deane at gooroos dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45065
