Hello Jared,
I've already tried to follow this approach before (and did it again just
now) and it seems that it doesn't work either.
Both section(".init")/section(".fini") and
section(".ctor")/section(".dtor") were tried.
No success even if I put __attribute__ before function's return type.
I took and built tcc from tinycc repository (tcc version 0.9.26 (x86-64
Linux)).
>From what I see it seems that __attribute__ is ignored entirely.
Below is a simple code which I used to test this functionality.
Thank you for your advice!
#include <stddef.h>
#include <stdio.h>
void init(void)
__attribute__((constructor)) __attribute__((section(".init")))
{
printf("init\n");
}
void fini(void)
__attribute__((destructor)) __attribute__((section(".fini")))
{
printf("fini\n");
}
int main(void)
{
printf("main\n");
return 0;
}
2015-09-10 7:40 GMT+03:00 Jared Maddox <[email protected]>:
> > Date: Fri, 4 Sep 2015 01:30:14 +0300
> > From: Dmitry Selyutin <[email protected]>
> > To: [email protected]
> > Subject: [Tinycc-devel] Shared libraries: startup and cleanup
> > Message-ID:
> > <
> camqzjev1m1ret8z25qbvgnwgf+jlm7fr397bfwwc9qjr_ty...@mail.gmail.com>
> > Content-Type: text/plain; charset="utf-8"
> >
> > Hello guys,
> >
> > first of all I'd like to thank everyone who takes part in tcc
> > development: it's amazing tool and actually the fastest and
> > smallest compiler I know about! I'm glad that I've found it
> > some years ago and especially glad that it is being developed
> > even now.
> >
> > The question I have is that I write an open-source project, a big
> > library which provides some Unicode functionality as well as
> > portable filesystem functions and various I/O stuff. I write in C89
> > with the POSIX standard in mind, but Woe32 is supported as well.
> > The only difficulty I met is that I need to find some analogue for
> > GCC's `__attribute__((constructor))' and `__attribute__((destructor))'.
> > This is the absolutely necessary evil, since I want to get path to
> > current directory right before `main()' is called.
> >
> > These attributes work under gcc and clang; they also seem to work
> > with pcc, though I prefer to use `_Pragma("init")' and `_Pragma("fini")'
> > instead. I even found the way to achieve the same goal in MSVC.
> > However, tcc seems to ignore `__attribute__', so this approach
> > doesn't help.
> >
> > A quick search approves my own investigations. It is a pity that tcc
> > lacks this feature; I know it is a non-standard but this is the only
> > reliable way to make an automatic library startup/cleanup without
> > forcing user to call some `weird_lib_init()' and `weird_lib_fini'
> > functions. Is this feature hard to implement? I don't know an
> > assembler, I only heard that this functionality is usually achieved via
> > some kind of `.ctors/.dtors' or `.init_array/.fini_array', where pointers
> > to functions (or their code?) are stored (well, for ELF). But probably
> > there may be a simpler way.
> >
> > I'd also like to help if this problem can be solved without assembler
> > code. If there is anything I can do I'd like to be useful, so please
> > don't hesitate to ask me! Could you please think about implementing
> > this feature?
> >
> > Thank you for your help!
>
> Haven't done this myself, but link:
> http://bellard.org/tcc/tcc-doc.html#SEC8
>
> tl;dr: __attribute__ should be supported, but you'll need to use
> section() in conjunction with it. This makes the entire subject more
> platform specific, so you'll need to research what exactly you need to
> do in C for each target platform. Basically you're looking for a way
> to register your function(s) as C++ -style constructors/destructors,
> and the way that it's done depends on the executable format.
>
> _______________________________________________
> Tinycc-devel mailing list
> [email protected]
> https://lists.nongnu.org/mailman/listinfo/tinycc-devel
>
--
With best regards,
Dmitry Selyutin
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