zeroc-ice
Review _iceS_ static object
When slice2cpp generates code for a class or an exception, it generates one static instance of the first class/exception in the header file: e.g.
// Metrics.h
// For the first class or exception defined in Metrics.ice, in this case class Metrics.
/// \cond INTERNAL
static Metrics _iceS_Metrics_init;
/// \endcond
According to the comment slice2cpp's code, this is for:
// We need an instance here to trigger initialization if the implementation is in a shared library.
// But we do this only once per source file, because a single instance is sufficient to initialize
// all of the globals in a shared library.
The comment does not seem accurate to me. We don't need an extra static in the header for the statics in the .cpp to get initialized in a shared library.
On the other hand, this could help with static builds: with this static in the header, including the header would ensure the statics in the .cpp are initialized even if you don't call anything else in the .cpp -- which is also a pretty rare use-case. Except it doesn't work now that the default ctor for generated classes and exceptions is "= default" i.e. inline. The construction of this static object doesn't need to execute code in the .cpp file and trigger the initialization of its statics.
As a test, I removed this static object with debug builds on macos, and the test-suite succeeds (shared and static). So we need to either:
- figure out why this static is useful, update the comment and add a test
- this could also require pytting the default ctor for generated classes and exceptions out of line
- remove this static object and related code in slice2cpp
