arm: rewrite crtbegin* as C files.
Rewrite
crtbegin.S -> crtbegin.c
crtbegin_so.S -> crtbegin_so.c
This change allows us to generate PIC code without relying
on text relocations.
As a consequence of this rewrite, also rewrite
__dso_handle.S -> __dso_handle.c
__dso_handle_so.S -> __dso_handle_so.c
atexit.S -> atexit.c
In crtbegin.c _start, place the __PREINIT_ARRAY__, __INIT_ARRAY__,
__FINI_ARRAY__, and __CTOR_LIST__ variables onto the stack, instead of
passing a pointer to the text section of the binary.
This change appears sorta wonky, as I attempted to preserve,
as much as possible, the structure of the original assembly.
As a result, you have C files including other C files, and other
programming uglyness.
Result: This change reduces the number of files with text-relocations
from 315 to 19 on my Android build.
Before:
$ scanelf -aR $OUT/system | grep TEXTREL | wc -l
315
After:
$ scanelf -aR $OUT/system | grep TEXTREL | wc -l
19
Change-Id: Ib9f98107c0eeabcb606e1ddc7ed7fc4eba01c9c4
diff --git a/libc/arch-arm/bionic/atexit.h b/libc/arch-arm/bionic/atexit.h
new file mode 100644
index 0000000..d567bfc
--- /dev/null
+++ b/libc/arch-arm/bionic/atexit.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/* CRT_LEGACY_WORKAROUND should only be defined when building
+ * this file as part of the platform's C library.
+ *
+ * The C library already defines a function named 'atexit()'
+ * for backwards compatibility with older NDK-generated binaries.
+ *
+ * For newer ones, 'atexit' is actually embedded in the C
+ * runtime objects that are linked into the final ELF
+ * binary (shared library or executable), and will call
+ * __cxa_atexit() in order to un-register any atexit()
+ * handler when a library is unloaded.
+ *
+ * This function must be global *and* hidden. Only the
+ * code inside the same ELF binary should be able to access it.
+ */
+
+#ifndef CRT_LEGACY_WORKAROUND
+extern void *__dso_handle;
+
+__attribute__ ((visibility ("hidden")))
+int atexit(void (*func)(void))
+{
+ return (__cxa_atexit((void (*)(void *))func, (void *)0, &__dso_handle));
+}
+#endif