<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Aug 6, 2015 at 1:21 PM, Edward Diener <span dir="ltr"><<a href="mailto:eldlistmailingz@tropicsoft.com" target="_blank">eldlistmailingz@tropicsoft.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">On 8/6/2015 12:44 PM, Reid Kleckner wrote:<br>
</span><span class=""><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hm, GCC never tries to import RTTI, so maybe it makes sense that we<br>
never export it. Anyway, there's a bug here. Maybe David knows what's up.<br>
</blockquote>
<br></span>
I tried this simple example:<br>
<br>
// ex_aclass.hpp<br>
<br>
#ifndef EX_ACLASS_HPP<br>
#define EX_ACLASS_HPP<span class=""><br>
#if defined(BLD_EX_EXAMPLE)<br>
#define EX_DECL __attribute__((__dllexport__))<br>
#else<br>
#define EX_DECL __attribute__((__dllimport__))<br>
#endif<br></span>
class EX_DECL ex_aclass<br>
{<br>
public:<br>
int a_function(long);<br>
};<br>
#endif // EX_ACLASS_HPP<br>
<br>
// ex_aclass.cpp<br>
<br>
#define BLD_EX_EXAMPLE<br>
#include "ex_aclass.hpp"<br>
int ex_aclass::a_function(long amt)<br>
{<br>
return(amt > 1000000 ? 10 : 20);<br>
}<br>
<br>
// Compile ex_aclass<br>
<br>
clang++.exe -c -x c++ -D__MINGW_FORCE_SYS_INTRINS -O0 -g -fno-inline -Wall -g -march=i686 -m32 -o "ex_aclass.obj" "ex_aclass.cpp"<br>
<br>
// Link to ex_ac dll<br>
<br>
clang++.exe -o "ex_ac.dll" -Wl,-soname -Wl,ex_ac.dll -shared -Wl,--start-group "ex_aclass.obj" -Wl,-Bstatic -Wl,-Bdynamic -Wl,--end-group -g -march=i686 -m32<br>
<br>
// ex_use_aclass.cpp<br>
<br>
#include "ex_aclass.hpp"<span class=""><br>
int main(int argc,char * argv[])<br>
{<br></span>
ex_aclass aclass;<br>
int ret(aclass.a_function(10000));<br>
return ret;<br>
}<br>
<br>
// Compile ex_use_aclass<br>
<br>
clang++.exe -c -x c++ -D__MINGW_FORCE_SYS_INTRINS -O0 -g -fno-inline -Wall -g -march=i686 -m32 -o "ex_use_aclass.obj" "ex_use_aclass.cpp"<br>
<br>
// Link ex_use_ac executable<br>
<br>
clang++.exe -Wl,-R -Wl,"." -Wl,-rpath-link -Wl,"." -o "ex_use_ac.exe" -Wl,--start-group "ex_use_aclass.obj" "ex_ac.dll" -Wl,-Bstatic -Wl,-Bdynamic -Wl,--end-group -g -march=i686 -m32<br>
<br>
All of this worked with no problems.<br>
<br>
So the basic ability to access functionality in a class in a DLL from outside that DLL works fine using clang on Windows. It is something specific in my original example below that is causing linking problems, whether I export entire classes or whether I export individual member functions. Just thought I would let you know. Needless to say I need to solve my original problem because that code mimics the design of a very small portion of the Boost serialization library and is the cause why the Boost serialization library will not build with clang on Windows targeting gcc.<br></blockquote><div><br></div><div>Should be fixed in r244266.<br></div><div><br></div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">
<br>
On Thu, Aug 6, 2015 at 9:36 AM, Reid Kleckner<br></span>
<<a href="mailto:rnk-hpIqsD4AKlfQT0dZR%2BAlfA@public.gmane.org" target="_blank">rnk-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org</a><div><div class="h5"><br>
<mailto:<a href="mailto:rnk-hpIqsD4AKlfQT0dZR%2BAlfA@public.gmane.org" target="_blank">rnk-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org</a>>> wrote:<br>
<br>
I reproduced your example, and it looks like we are forgetting to<br>
export RTTI with dllexport in Itanium. We only export the vtable.<br>
This is what each compiler exports for ex_xml_exception.obj:<br>
<br>
$ dumpbin -directives ex_xml_exception.clang.obj | grep -export:_ZT<br>
| c++filt --no-strip-underscore<br>
-export:virtual thunk to ex_xml_exception::~ex_xml_exception()<br>
-export:virtual thunk to ex_xml_exception::~ex_xml_exception()<br>
-export:vtable for ex_xml_exception,data<br>
<br>
$ dumpbin -directives ex_xml_exception.gcc.obj | grep -export:_ZT |<br>
c++filt --no-strip-underscore<br>
-export:typeinfo for ex_exception,data<br>
-export:typeinfo for ex_xml_exception,data<br>
-export:construction vtable for<br>
ex_exception-in-ex_xml_exception,data<br>
-export:VTT for ex_xml_exception,data<br>
-export:vtable for ex_xml_exception,data<br>
-export:virtual thunk to ex_xml_exception::~ex_xml_exception()<br>
-export:virtual thunk to ex_xml_exception::~ex_xml_exception()<br>
<br>
In your previous example where the whole class wasn't exported, I<br>
think we might be doing the wrong thing when the key function is<br>
dllimport / dllexport. We think that it will provide exported<br>
symbols for vtables and RTTI but it doesn't. This is something we<br>
didn't run into because the MSVC ABI doesn't have key functions.<br>
<br>
On Thu, Aug 6, 2015 at 6:16 AM, Edward Diener<br>
<<a href="mailto:eldlistmailingz@tropicsoft.com" target="_blank">eldlistmailingz@tropicsoft.com</a><br></div></div><div><div class="h5">
<mailto:<a href="mailto:eldlistmailingz-5p0dqD" target="_blank">eldlistmailingz-5p0dqD</a>/<a href="mailto:c5LGWd6l5hS35sQ@public.gmane.org" target="_blank">c5LGWd6l5hS35sQ@public.gmane.org</a>>> wrote:<br>
<br>
Using clang on Windows targeting mingw(-64)/gcc since it does<br>
not appear possible to export individual member functions of a<br>
class, as well as export the RTTI of the class, without<br>
exporting the entire class, I have changed my example in my post<br>
"Linker error and obfuscated name" to export the entire class<br>
itself. But I am still seeing a linker error, Here is the<br>
changed code and command lines:<br>
<br>
// ex_decl.hpp<br>
<br>
#ifndef EX_DECL_HPP<br>
#define EX_DECL_HPP<br>
#if defined(BLD_EX_EXAMPLE)<br>
#define EX_DECL __attribute__((__dllexport__))<br>
#else<br>
#define EX_DECL __attribute__((__dllimport__))<br>
#endif<br>
#endif // EX_DECL_HPP<br>
<br>
// ex_exception.hpp<br>
<br>
#ifndef EX_EXCEPTION_HPP<br>
#define EX_EXCEPTION_HPP<br>
#include <exception><br>
#include "ex_decl.hpp"<br>
class EX_DECL ex_exception :<br>
public virtual std::exception<br>
{<br>
private:<br>
char m_buffer[128];<br>
protected:<br>
unsigned int append(unsigned int l, const char * a);<br>
ex_exception() ;<br>
public:<br>
typedef enum {<br>
no_exception,<br>
other_exception<br>
} ex_exception_code;<br>
ex_exception_code code;<br>
ex_exception(ex_exception_code c,const char * e1 = 0,const<br>
char * e2 = 0) ;<br>
ex_exception(ex_exception const &) ;<br>
virtual ~ex_exception() throw() ;<br>
virtual const char * what() const throw() ;<br>
};<br>
#endif // EX_EXCEPTION_HPP<br>
<br>
// ex_exception.cpp<br>
<br>
#include <exception><br>
#include <cstring><br>
#define BLD_EX_EXAMPLE<br>
#include "ex_exception.hpp"<br>
unsigned int ex_exception::append(unsigned int l, const char * a){<br>
while(l < (sizeof(m_buffer) - 1)){<br>
char c = *a++;<br>
if('\0' == c)<br>
break;<br>
m_buffer[l++] = c;<br>
}<br>
m_buffer[l] = '\0';<br>
return l;<br>
}<br>
ex_exception::ex_exception(ex_exception_code c,const char *<br>
e1,const char * e2) : code(c)<br>
{<br>
unsigned int length = 0;<br>
switch(code){<br>
case no_exception:<br>
length = append(length, "uninitialized exception");<br>
break;<br>
case other_exception:<br>
length = append(length, "unknown derived exception");<br>
break;<br>
default:<br>
length = append(length, "programming error");<br>
break;<br>
}<br>
}<br>
ex_exception::ex_exception(ex_exception const & oth) :<br>
std::exception(oth),code(oth.code)<br>
{<br>
std::memcpy(m_buffer,oth.m_buffer,sizeof m_buffer);<br>
}<br>
ex_exception::~ex_exception() throw() {}<br>
const char * ex_exception::what() const throw() { return<br>
m_buffer; }<br>
ex_exception::ex_exception() : code(no_exception) {}<br>
<br>
// Compile ex_exception.cpp<br>
<br>
clang++.exe -c -x c++ -D__MINGW_FORCE_SYS_INTRINS<br>
-Wno-unused-local-typedef -Wno-dll-attribute-on-redeclaration<br>
-O0 -g -fno-inline -Wall -g -march=i686 -m32 -o<br>
"ex_exception.obj" "ex_exception.cpp"<br>
<br>
// ex_xml_exception.hpp<br>
<br>
#ifndef EX_XML_EXCEPTION_HPP<br>
#define EX_XML_EXCEPTION_HPP<br>
#include <exception><br>
#include "ex_decl.hpp"<br>
#include "ex_exception.hpp"<br>
class EX_DECL ex_xml_exception :<br>
public virtual ex_exception<br>
{<br>
public:<br>
typedef enum {<br>
xml_archive_parsing_error,<br>
xml_archive_tag_mismatch,<br>
xml_archive_tag_name_error<br>
} ex_exception_code;<br>
ex_xml_exception(ex_exception_code c,const char * e1 =<br>
0,const char * e2 = 0);<br>
ex_xml_exception(ex_xml_exception const &) ;<br>
virtual ~ex_xml_exception() throw() ;<br>
};<br>
#endif // EX_XML_EXCEPTION_HPP<br>
<br>
// ex_xml_exception.cpp<br>
<br>
#include <exception><br>
#define BLD_EX_EXAMPLE<br>
#include "ex_xml_exception.hpp"<br>
ex_xml_exception::ex_xml_exception(ex_exception_code c,const<br>
char * e1,const char * e2) :<br>
ex_exception(other_exception, e1, e2)<br>
{<br>
switch(c){<br>
case xml_archive_parsing_error:<br>
ex_exception::append(0, "unrecognized XML syntax");<br>
break;<br>
case xml_archive_tag_mismatch:<br>
ex_exception::append(0, "XML start/end tag mismatch");<br>
if(0 != e1){<br>
ex_exception::append(0, " - ");<br>
ex_exception::append(0, e1);<br>
}<br>
break;<br>
case xml_archive_tag_name_error:<br>
ex_exception::append(0, "Invalid XML tag name");<br>
break;<br>
default:<br>
ex_exception::append(0, "programming error");<br>
break;<br>
}<br>
}<br>
ex_xml_exception::ex_xml_exception(ex_xml_exception const & oth)<br>
: std::exception(oth),ex_exception(oth){}<br>
ex_xml_exception::~ex_xml_exception() throw() {}<br>
<br>
// Compile ex_xml_exception.cpp<br>
<br>
clang++.exe -c -x c++ -D__MINGW_FORCE_SYS_INTRINS<br>
-Wno-unused-local-typedef -Wno-dll-attribute-on-redeclaration<br>
-O0 -g -fno-inline -Wall -g -march=i686 -m32 -o<br>
"ex_xml_exception.obj" "ex_xml_exception.cpp"<br>
<br>
// Link exmp-clang37-d-1_59.dll<br>
<br>
clang++.exe -o "exmp-clang37-d-1_59.dll" -Wl,-soname<br>
-Wl,exmp-clang37-d-1_59.dll -shared -Wl,--start-group<br>
"ex_exception.obj" "ex_xml_exception.obj" -Wl,-Bstatic<br>
-Wl,-Bdynamic -Wl,--end-group -g -march=i686 -m32<br>
<br>
// throw_exception_ex.cpp<br>
<br>
#include "ex_xml_exception.hpp"<br>
template<class E> void throw_exception(E const & e) { throw e; }<br>
int main(int argc,char * argv[])<br>
{<br>
if (argc > 1)<br>
{<br>
<br>
throw_exception(ex_xml_exception(ex_xml_exception::xml_archive_parsing_error));<br>
<br>
}<br>
return 0;<br>
}<br>
<br>
// Compile throw_exception_ex.cpp<br>
<br>
clang++.exe -c -x c++ -D__MINGW_FORCE_SYS_INTRINS<br>
-Wno-unused-local-typedef -Wno-dll-attribute-on-redeclaration<br>
-O0 -g -fno-inline -Wall -g -march=i686 -m32 -o<br>
"throw_exception_ex.obj" "throw_exception_ex.cpp"<br>
<br>
// Link thr_exmp.exe<br>
<br>
clang++.exe -Wl,-R -Wl,"." -Wl,-rpath-link -Wl,"." -o<br>
"thr_exmp.exe" -Wl,--start-group "throw_exception_ex.obj"<br>
"exmp-clang37-d-1_59.dll" -Wl,-Bstatic -Wl,-Bdynamic<br>
-Wl,--end-group -g -march=i686 -m32<br>
<br>
// Error message from this link<br>
<br>
throw_exception_ex.obj: In function<br>
`Z15throw_exceptionI16ex_xml_exceptionEvRKT_':<br>
throw_exception_ex.cpp:2: undefined reference to<br>
`_imp___ZTI16ex_xml_exception'<br>
clang++.exe: error: linker command failed with exit code 1 (use<br>
-v to see invocation)<br>
<br>
So even when I export/import the entire class rather than<br>
individual member functions, I can not link my final module<br>
successfully as it is still looking for something in the shared<br>
library that it says is not there.<br>
<br>
This same code succeeds without problem with mingw(-64)/gcc on<br>
Windows.<br>
</div></div></blockquote><div class="HOEnZb"><div class="h5">
<br>
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