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aix: collect2 visibility

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The code that collect2 generates, compiles and links into applications
and shared libraries to initialize constructors and register DWARF tables
is built with the compiler options used to invoke the linker.  If the
compiler options change the visibility from default, the library
initialization routines will not be visible and this can prevent
initialization.

This patch checks if the command line sets visibiliity and then adds
GCC pragmas to the initialization code generated by collect2 if
necessary to define the visibility on global, exported functions as default.

gcc/ChangeLog:

2020-09-26  David Edelsohn  <dje.gcc@gmail.com>
	    Clement Chigot  <clement.chigot@atos.com>

	* collect2.c (visibility_flag): New.
	(main): Detect -fvisibility.
	(write_c_file_stat): Push and pop default visibility.
This commit is contained in:
David Edelsohn 2020-09-23 16:52:15 -04:00
parent 5b26b3b3f5
commit e721d1137f
1 changed files with 25 additions and 1 deletions
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26
gcc/collect2.c
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@ -184,7 +184,8 @@ static int strip_flag; /* true if -s */
static int export_flag; /* true if -bE */
static int aix64_flag; /* true if -b64 */
static int aixrtl_flag; /* true if -brtl */
static int aixlazy_flag; /* true if -blazy */
static int aixlazy_flag; /* true if -blazy */
static int visibility_flag; /* true if -fvisibility */
#endif
enum lto_mode_d {
@ -1239,6 +1240,11 @@ main (int argc, char **argv)
*c_ptr++ = xstrdup (q);
}
}
#ifdef COLLECT_EXPORT_LIST
/* Detect any invocation with -fvisibility. */
if (strncmp (q, "-fvisibility", 12) == 0)
visibility_flag = 1;
#endif
}
obstack_free (&temporary_obstack, temporary_firstobj);
*c_ptr++ = "-fno-profile-arcs";
@ -2131,6 +2137,11 @@ write_c_file_stat (FILE *stream, const char *name ATTRIBUTE_UNUSED)
fprintf (stream, "\t}\n");
}
#ifdef COLLECT_EXPORT_LIST
/* Set visibility of initializers to default. */
if (visibility_flag)
fprintf (stream, "#pragma GCC visibility push(default)\n");
#endif
fprintf (stream, "void %s() {\n", initname);
if (constructors.number > 0 || frames)
{
@ -2163,11 +2174,24 @@ write_c_file_stat (FILE *stream, const char *name ATTRIBUTE_UNUSED)
destructors.number + frames);
}
fprintf (stream, "}\n");
#ifdef COLLECT_EXPORT_LIST
if (visibility_flag)
fprintf (stream, "#pragma GCC visibility pop\n");
#endif
if (shared_obj)
{
#ifdef COLLECT_EXPORT_LIST
/* Set visibility of initializers to default. */
if (visibility_flag)
fprintf (stream, "#pragma GCC visibility push(default)\n");
#endif
COLLECT_SHARED_INIT_FUNC (stream, initname);
COLLECT_SHARED_FINI_FUNC (stream, fininame);
#ifdef COLLECT_EXPORT_LIST
if (visibility_flag)
fprintf (stream, "#pragma GCC visibility pop\n");
#endif
}
}