Experimental Physics and
Industrial Control System

Dirk Zimoch <[email protected]> · Tue, 13 Mar 2012 11:07:04 +0100

Andrew, Lewis,

If the C++ template instantiation is the problem, then the

-fno-implicit-templates command line option may help. If that is used,

the compiler will not create any code "behind the scenes".

Instead it requires that for each template, you explicitly specify in

which file you want to have the implementation. See section "Where's the

Template?" in the gcc info pages.

In exactly one source code file one has to write a line like
template class epicsSingleton<localHostName>::reference;

Dirk

Andrew Johnson wrote:

Hi Dirk,

On 3/7/12 2:50 AM, Dirk Zimoch wrote:

These two functions,
epicsSingleton<localHostName>::reference::~reference(void) and
epicsSingleton<localHostName>::reference::operator->(void) both
contain 'assert' (see src/libCom/cxxTemplates/epicsSingleton.h).

'assert' is a macro:
#   define assert(exp) ((exp) ? (void)0 : \
        epicsAssert(__FILE__, __LINE__, #exp, epicsAssertAuthor))

Depending on the optimization level, '(void)0' may be eliminated
and the code becomes shorter (by 4 bytes = 1 PPC instruction).

Try to 'make clean' in the epics base top directory and compile
again.

The problem is more subtle than that, although I suspect that different

optimization levels is probably the underlying cause.

Remember Lewis is using a very old version of g++, from back when C++

templates were new; my guess is that ldppc is recompiling the template

instances it needs to link the code behind the scenes, but it wasn't told the

optimization level that g++ppc used to compile the instances that appear in

the .o files it's linking with so it doesn't get the same length code and

generates that warning. There may be a flag we could turn on to show more

about what's going on inside ldppc, but it's really not worth looking into

IMHO; better to spend the time upgrading to vxWorks 5.5.

- Andrew

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System