Allow static C++ destructors to be properly called on dlclose().

With this patch, _and_ an upcoming build/ patch, the destruction
of static C++ objects contained in shared libraries will happen
properly when dlclose() is called.

Note that this change introduces crtbegin_so.S and crtend_so.S which
are currently ignored by the build system.

+ move definition of __dso_handle to the right place
  (before that, all shared libraries used the __dso_handle
   global variable from the C library).

  Note that we keep a 'weak' __dso_handle in aeabi.c to avoid
  breaking the build until the next patch to build/core/combo/
  appears. We will be able to remove that later.

+ move bionic/aeabi.c to arch-arm/bionic/ (its proper location)

Change-Id: Ie771aa204e3acbdf02fd30ebd4150373a1398f39
NOTE: The NDK will need to be modified to enable this feature in
      the shared libraries that are generated through it.

5 files changed, 218 insertions, 15 deletions

diff --git a/libc/arch-arm/bionic/crtbegin_dynamic.S b/libc/arch-arm/bionic/crtbegin_dynamic.S
index e265923..d18e715 100644
--- a/libc/arch-arm/bionic/crtbegin_dynamic.S
+++ b/libc/arch-arm/bionic/crtbegin_dynamic.S
@@ -31,7 +31,7 @@
 	.globl _start
 
 # this is the small startup code that is first run when
-# any executable that is statically-linked with Bionic
+# any executable that is dynamically-linked with Bionic
 # runs.
 #
 # it's purpose is to call __libc_init with appropriate
@@ -63,13 +63,7 @@ _start:
     .long   __INIT_ARRAY__
     .long   __FINI_ARRAY__
     .long   __CTOR_LIST__
-      
-# the .ctors section contains a list of pointers to "constructor"
-# functions that need to be called in order during C library initialization,
-# just before the program is being run. This is a C++ requirement
-#
-# the last entry shall be 0, and is defined in crtend.S
-#
+
 	.section .preinit_array, "aw"
 	.globl __PREINIT_ARRAY__
 __PREINIT_ARRAY__:
@@ -90,3 +84,4 @@ __FINI_ARRAY__:
 __CTOR_LIST__:
 	.long -1
 
+#include "__dso_handle.S"
diff --git a/libc/arch-arm/bionic/crtbegin_so.S b/libc/arch-arm/bionic/crtbegin_so.S
new file mode 100644
index 0000000..bb6b3e2
--- /dev/null
+++ b/libc/arch-arm/bionic/crtbegin_so.S
@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2008 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.
+ */
+
+# Implement static C++ destructors when the shared
+# library is unloaded through dlclose().
+#
+# A call to this function must be the first entry
+# in the .fini_array. See 3.3.5.3.C of C++ ABI
+# standard.
+#
+__on_dlclose:
+        adr     r0, 0f
+        ldr     r0, [r0]
+        b       __cxa_finalize
+
+0:
+        .long   __dso_handle
+
+	.section .init_array, "aw"
+	.globl __INIT_ARRAY__
+__INIT_ARRAY__:
+	.long -1
+
+        .section .fini_array, "aw"
+        .globl __FINI_ARRAY__
+__FINI_ARRAY__:
+        .long -1
+        .long __on_dlclose
+
+#include "__dso_handle.S"
diff --git a/libc/arch-arm/bionic/crtbegin_static.S b/libc/arch-arm/bionic/crtbegin_static.S
index e265923..6f9cf25 100644
--- a/libc/arch-arm/bionic/crtbegin_static.S
+++ b/libc/arch-arm/bionic/crtbegin_static.S
@@ -63,13 +63,7 @@ _start:
     .long   __INIT_ARRAY__
     .long   __FINI_ARRAY__
     .long   __CTOR_LIST__
-      
-# the .ctors section contains a list of pointers to "constructor"
-# functions that need to be called in order during C library initialization,
-# just before the program is being run. This is a C++ requirement
-#
-# the last entry shall be 0, and is defined in crtend.S
-#
+
 	.section .preinit_array, "aw"
 	.globl __PREINIT_ARRAY__
 __PREINIT_ARRAY__:
@@ -90,3 +84,5 @@ __FINI_ARRAY__:
 __CTOR_LIST__:
 	.long -1
 
+
+#include "__dso_handle.S"
diff --git a/libc/arch-arm/bionic/crtend_so.S b/libc/arch-arm/bionic/crtend_so.S
new file mode 100644
index 0000000..a1281c4
--- /dev/null
+++ b/libc/arch-arm/bionic/crtend_so.S
@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2010 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.
+ */
+
+/* This is the same than crtend.S except that a shared library
+ * cannot have a .preinit_array
+ */
+	
+	.section .init_array, "aw"
+	.long 0
+
+	.section .fini_array, "aw"
+	.long 0
+
diff --git a/libc/arch-arm/bionic/eabi.c b/libc/arch-arm/bionic/eabi.c
new file mode 100644
index 0000000..3f26f2b
--- /dev/null
+++ b/libc/arch-arm/bionic/eabi.c
@@ -0,0 +1,119 @@
+/*
+ * Copyright (C) 2008 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.
+ */
+#include <stddef.h>
+#include <string.h>
+
+extern int  __cxa_atexit(void (*)(void*), void*, void* );
+
+/* Temporary hack: this variable should not be part of the C library
+ * itself, but placed in the .bss section of each executable or
+ * shared library instead.
+ *
+ * We keep it here temporarily until the build system has been
+ * modified properly to use crtbegin_so.S and crtend_so.S when
+ * generating shared libraries.
+ *
+ * It must be a 'weak' symbol to avoid conflicts with the definitions
+ * that have been moved to crtbegin_static.S and crtbegin_dynamic.S
+ *
+ * For the record, it is used for static C++ object construction
+ * and destruction. See http://www.codesourcery.com/public/cxx-abi/abi.html#dso-dtor
+ */
+void* __attribute__((weak)) __dso_handle;
+
+/* The "C++ ABI for ARM" document states that static C++ constructors,
+ * which are called from the .init_array, should manually call
+ * __aeabi_atexit() to register static destructors explicitely.
+ *
+ * Note that 'dso_handle' is the address of a magic linker-generate
+ * variable from the shared object that contains the constructor/destructor
+ */
+
+/* Make this a weak symbol to avoid a multiple definition error when linking
+ * with libstdc++-v3.  */
+int __attribute__((weak))
+__aeabi_atexit (void *object, void (*destructor) (void *), void *dso_handle)
+{
+    return __cxa_atexit(destructor, object, dso_handle);
+}
+
+
+void __aeabi_memcpy8(void *dest, const void *src, size_t n) {
+    memcpy(dest, src, n);
+}
+
+void __aeabi_memcpy4(void *dest, const void *src, size_t n) {
+    memcpy(dest, src, n);
+}
+
+void __aeabi_memcpy(void *dest, const void *src, size_t n) {
+    memcpy(dest, src, n);
+}
+
+
+void __aeabi_memmove8(void *dest, const void *src, size_t n) {
+    memmove(dest, src, n);
+}
+
+void __aeabi_memmove4(void *dest, const void *src, size_t n) {
+    memmove(dest, src, n);
+}
+
+void __aeabi_memmove(void *dest, const void *src, size_t n) {
+    memmove(dest, src, n);
+}
+
+/*
+ * __aeabi_memset has the order of its second and third arguments reversed. 
+ *  This allows __aeabi_memclr to tail-call __aeabi_memset
+ */
+ 
+void __aeabi_memset8(void *dest, size_t n, int c) {
+    memset(dest, c, n);
+}
+
+void __aeabi_memset4(void *dest, size_t n, int c) {
+    memset(dest, c, n);
+}
+
+void __aeabi_memset(void *dest, size_t n, int c) {
+    memset(dest, c, n);
+}
+
+
+void __aeabi_memclr8(void *dest, size_t n) {
+    __aeabi_memset8(dest, n, 0);
+}
+
+void __aeabi_memclr4(void *dest, size_t n) {
+    __aeabi_memset4(dest, n, 0);
+}
+
+void __aeabi_memclr(void *dest, size_t n) {
+    __aeabi_memset(dest, n, 0);
+}