Summary:
= The Rationale =
EAPI was designed to be able to pass
`__attribute__ ((visibility ("default")))` for symbols with
GCC, which would mean that even if -fvisibility=hidden was used
when compiling the library, the needed symbols would get exported.
MSVC __almost__ works like GCC (or mingw) in which you can
declare everything as export and it will just work (slower, but
it will work). But there's a caveat: global variables will not
work the same way for MSVC, but works for mingw and GCC.
For global variables (as opposed to functions), MSVC requires
correct DSO visibility for MSVC: instead of declaring a symbol as
export for everything, you need to declare it as import when
importing from another DSO and export when defining it locally.
With current EAPI definitions, we get the following example
working in mingw and MSVC (observe it doesn't define any global
variables as exported symbols).
Example 1:
dll1:
```
EAPI void foo(void);
EAPI void bar()
{
foo();
}
```
dll2:
```
EAPI void foo()
{
printf ("foo\n");
}
```
This works fine with API defined as __declspec(dllexport) in both
cases and for gcc defining as
`__atttribute__((visibility("default")))`.
However, the following:
Example 2:
dll1:
```
EAPI extern int foo;
EAPI void foobar(void);
EAPI void bar()
{
foo = 5;
foobar();
}
```
dll2:
```
EAPI int foo = 0;
EAPI void foobar()
{
printf ("foo %d\n", foo);
}
```
This will work on mingw but will not work for MSVC. And that's why
EAPI is the only solution that worked for MSVC.
Co-authored-by: João Paulo Taylor Ienczak Zanette <jpaulotiz@gmail.com>
Co-authored-by: Ricardo Campos <ricardo.campos@expertise.dev>
Co-authored-by: Lucas Cavalcante de Sousa <lucks.sousa@gmail.com>
Reviewers: vtorri, raster
Reviewed By: raster
Subscribers: raster, cedric, #reviewers, #committers
Tags: #efl
Differential Revision: https://phab.enlightenment.org/D12271
please note, not the return type, but the function.
When appending __attribute__((const)) to a function, the compiler is
told that its enough to call this function once in a function.
This is quite often happening when we are efl_data_scope_get and
efl_super in a function that is different from a implemented function.
The compiler now starts to remove the calls that aggressivly that we
need to ensure that these calls are not removed, which means, the static
function calls, and the eo init are now checking the return value of
these functions, to ensure that they are called.
Please note that you now have to be carefull when your app calls
eo_shutdown, if it does so, you *must* call it at the end of a function,
or never call class_get after that anymore.
Overall this improves elm test runs 0.1s which is fair i guess, the main
thing that is faster is textrendering, where is also the point where
this is the most beneficial.
Please note, this replaces 42 occurences of double _class_get() ... THAT
is a sign!
Reviewed-by: Stefan Schmidt <stefan@datenfreihafen.org>
Reviewed-by: Daniel Kolesa <daniel@octaforge.org>
Differential Revision: https://phab.enlightenment.org/D12057
this takes the current generated output from eolian for legacy code in
evas and adds it to the tree, then removes legacy references from the
corresponding eo files. in the case where the entire eo file was for
a legacy object, that eo file has been removed from the tree
ref T7724
Reviewed-by: Cedric BAIL <cedric.bail@free.fr>
Differential Revision: https://phab.enlightenment.org/D8125
Felipe Magno de Almeida
Marcel Hollerbach
Xavi Artigas
Mike Blumenkrantz