[PATCH] eal: provide trace point register macro for MSVC

[Tyler Retzlaff]

On Mon, Nov 06, 2023 at 05:40:12PM +0100, Thomas Monjalon wrote:
> 01/11/2023 23:47, Tyler Retzlaff:
> > Provide an alternate RTE_TRACE_POINT_REGISTER macro when building with
> > MSVC that allocates segments for the trace point using MSVC specific
> > features
> 
> Please could you elaborate what is the improvement?

well not intended to be an improvement, intended to align the msvc build
with the gcc/clang builds placement of registered tracepoint in their
own section.

the alternate expansion for msvc is provided to place the trace point
being registered in it's own section `__rte_trace_point'

msvc doesn't have __attribute__(section("name")) instead as an alternate
we use msvc's data_seg pragma to create and place the trace point into
a named section.

i.e.
gcc/clang
T __attribute__(section("__rte_trace_point") __##trace;
msvc
T __pragma(data_seg("__rte_trace_point")) __declspec(allocate("__rte_trace_point")) __##trace;

> 
> > +#define RTE_TRACE_POINT_REGISTER(trace, name) \
> > +rte_trace_point_t \
> > +__pragma(data_seg("__rte_trace_point")) \
> > +__declspec(allocate("__rte_trace_point")) \
> > +__##trace; \
> > +static const char __##trace##_name[] = RTE_STR(name); \
> > +RTE_INIT(trace##_init) \
> > +{ \
> > +	__rte_trace_point_register(&__##trace, __##trace##_name, \
> > +		(void (*)(void)) trace); \
> > +}
> 
>