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/crtbegin.c b/libc/arch-arm/bionic/crtbegin.c
new file mode 100644
index 0000000..9dcd254
--- /dev/null
+++ b/libc/arch-arm/bionic/crtbegin.c
@@ -0,0 +1,73 @@
+/*
+ * 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.
+ */
+
+typedef struct
+{
+ void (**preinit_array)(void);
+ void (**init_array)(void);
+ void (**fini_array)(void);
+ void (**ctors_array)(void);
+} structors_array_t;
+
+extern int main(int argc, char **argv, char **env);
+
+extern void __libc_init(
+ unsigned int *elfdata,
+ void (*onexit)(void),
+ int (*slingshot)(int, char**, char**),
+ structors_array_t const * const structors
+);
+
+__attribute__ ((section (".preinit_array")))
+void (*__PREINIT_ARRAY__)(void) = (void (*)(void)) -1;
+
+__attribute__ ((section (".init_array")))
+void (*__INIT_ARRAY__)(void) = (void (*)(void)) -1;
+
+__attribute__ ((section (".fini_array")))
+void (*__FINI_ARRAY__)(void) = (void (*)(void)) -1;
+
+__attribute__ ((section (".ctors")))
+void (*__CTOR_LIST__)(void) = (void (*)(void)) -1;
+
+__attribute__((visbility("hidden")))
+void _start() {
+ structors_array_t array;
+ void *elfdata;
+
+ array.preinit_array = &__PREINIT_ARRAY__;
+ array.init_array = &__INIT_ARRAY__;
+ array.fini_array = &__FINI_ARRAY__;
+ array.ctors_array = &__CTOR_LIST__;
+
+ elfdata = __builtin_frame_address(0) + sizeof(void *);
+ __libc_init(elfdata, (void *) 0, &main, &array);
+}
+
+#include "__dso_handle.h"
+#include "atexit.h"