summaryrefslogtreecommitdiff
path: root/libc/sysdeps/linux/common/initfini.c
diff options
context:
space:
mode:
Diffstat (limited to 'libc/sysdeps/linux/common/initfini.c')
-rw-r--r--libc/sysdeps/linux/common/initfini.c134
1 files changed, 134 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/common/initfini.c b/libc/sysdeps/linux/common/initfini.c
new file mode 100644
index 000000000..147de8748
--- /dev/null
+++ b/libc/sysdeps/linux/common/initfini.c
@@ -0,0 +1,134 @@
+/* Special .init and .fini section support.
+ Copyright (C) 1995, 1996, 1997, 2000 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ In addition to the permissions in the GNU Lesser General Public
+ License, the Free Software Foundation gives you unlimited
+ permission to link the compiled version of this file with other
+ programs, and to distribute those programs without any restriction
+ coming from the use of this file. (The GNU Lesser General Public
+ License restrictions do apply in other respects; for example, they
+ cover modification of the file, and distribution when not linked
+ into another program.)
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+/* This file is compiled into assembly code which is then munged by a sed
+ script into two files: crti.s and crtn.s.
+
+ * crti.s puts a function prologue at the beginning of the
+ .init and .fini sections and defines global symbols for
+ those addresses, so they can be called as functions.
+
+ * crtn.s puts the corresponding function epilogues
+ in the .init and .fini sections. */
+
+#include <stdlib.h>
+
+#undef GMON_SUPPORT
+
+/* We use embedded asm for .section unconditionally, as this makes it
+ easier to insert the necessary directives into crtn.S. */
+#define SECTION(x) asm (".section " x )
+
+/* The initial common code ends here. */
+asm ("\n/*@HEADER_ENDS*/");
+
+/* To determine whether we need .end and .align: */
+//asm ("\n/*@TESTS_BEGIN*/");
+extern void dummy (void (*foo) (void));
+void
+dummy (void (*foo) (void))
+{
+ if (foo)
+ (*foo) ();
+}
+//asm ("\n/*@TESTS_END*/");
+
+/* The beginning of _init: */
+asm ("\n/*@_init_PROLOG_BEGINS*/");
+
+#ifdef GMON_SUPPORT
+static void
+call_gmon_start(void)
+{
+ extern void __gmon_start__ (void) __attribute__ ((weak)); /*weak_extern (__gmon_start__);*/
+ void (*gmon_start) (void) = __gmon_start__;
+
+ if (gmon_start)
+ gmon_start ();
+}
+#endif
+
+SECTION (".init");
+extern void _init (void);
+void
+_init (void)
+{
+#ifdef GMON_SUPPORT
+ /* We cannot use the normal constructor mechanism in gcrt1.o because it
+ appears before crtbegin.o in the link, so the header elt of .ctors
+ would come after the elt for __gmon_start__. One approach is for
+ gcrt1.o to reference a symbol which would be defined by some library
+ module which has a constructor; but then user code's constructors
+ would come first, and not be profiled. */
+ call_gmon_start ();
+#endif
+
+ asm ("ALIGN");
+ asm("END_INIT");
+ /* Now the epilog. */
+ asm ("\n/*@_init_PROLOG_ENDS*/");
+ asm ("\n/*@_init_EPILOG_BEGINS*/");
+ SECTION(".init");
+}
+asm ("END_INIT");
+
+/* End of the _init epilog, beginning of the _fini prolog. */
+asm ("\n/*@_init_EPILOG_ENDS*/");
+asm ("\n/*@_fini_PROLOG_BEGINS*/");
+
+SECTION (".fini");
+extern void _fini (void);
+void
+_fini (void)
+{
+
+ /* End of the _fini prolog. */
+ asm ("ALIGN");
+ asm ("END_FINI");
+ asm ("\n/*@_fini_PROLOG_ENDS*/");
+
+ {
+ /* Let GCC know that _fini is not a leaf function by having a dummy
+ function call here. We arrange for this call to be omitted from
+ either crt file. */
+ extern void i_am_not_a_leaf (void);
+ i_am_not_a_leaf ();
+ }
+
+ /* Beginning of the _fini epilog. */
+ asm ("\n/*@_fini_EPILOG_BEGINS*/");
+ SECTION (".fini");
+}
+asm ("END_FINI");
+
+/* End of the _fini epilog. Any further generated assembly (e.g. .ident)
+ is shared between both crt files. */
+asm ("\n/*@_fini_EPILOG_ENDS*/");
+asm ("\n/*@TRAILER_BEGINS*/");
+
+/* End of file. */