[Bug modula2/108183] wrong code generated in the modula2 scaffold mechanism
iains at gcc dot gnu.org
gcc-bugzilla@gcc.gnu.org
Tue Dec 20 09:36:05 GMT 2022
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108183
--- Comment #4 from Iain Sandoe <iains at gcc dot gnu.org> ---
(In reply to Gaius Mulley from comment #3)
> The scaffold array (referencing each module ctor) is generated
> gcc/m2/gm2-compiler/M2Quads.mod:2402 and ctors are created in:
> gcc/m2/gm2-gcc/m2decl.cc
terms was one example (of several cases)
I had already found the code in M2Quads & Scaffold and m2decl.cc.
However, not being familiar with m2 (or the design here) .. that was not
leading me to the right code.
It seems that m2decl_DeclareModuleCtor is only called for the module that *is*
in the current TU (so Hello, in the case of a hello world example). I've tried
putting breakpoints on m2decl_BuildEndFunctionDeclaration() [which seems to be
called for some of the actors, but I do not (for example) see a call for
_M2_termios_ctor).
In the termios.cc file:
struct _M2_termios_ctor { _M2_termios_ctor (); } _M2_termios_ctor;
the symbol '_M2_termios_ctor' does not seem to refer to a function, but to a
static instance of struct _M2_termios_ctor .. so I'm still confused about what
is supposed to happen.
===
extern "C" void
_M2_termios_init (int, char *[], char *[])
{
}
extern "C" void
_M2_termios_fini (int, char *[], char *[])
{
}
extern "C" void
_M2_termios_dep (void)
{
}
struct _M2_termios_ctor { _M2_termios_ctor (); } _M2_termios_ctor;
_M2_termios_ctor::_M2_termios_ctor (void)
{
// M2RTS_RegisterModule ("termios", _M2_termios_init, _M2_termios_fini,
// _M2_termios_dep);
}
===
.globl __M2_termios_fini
__M2_termios_fini:
ret
.globl __M2_termios_dep
__M2_termios_dep:
ret
// here are the CTORs...
.align 1,0x90
.globl __ZN16_M2_termios_ctorC2Ev
__ZN16_M2_termios_ctorC2Ev:
ret
.align 1,0x90
.globl __ZN16_M2_termios_ctorC1Ev
__ZN16_M2_termios_ctorC1Ev:
ret:
// and here is the external symbol __M2_termios_ctor
// (ignore the extra leading '_' that's an ABI thing)
.globl __M2_termios_ctor
.zerofill __DATA,__common,__M2_termios_ctor,1,0
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