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

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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.
This commit is contained in:
David 'Digit' Turner 2010-06-18 14:47:22 -07:00
parent 6a09cfd9f9
commit 6a9b888d7c
12 changed files with 186 additions and 38 deletions
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22
libc/Android.mk
View File

@ -317,7 +317,6 @@ libc_common_src_files := \
# =========================================================
ifeq ($(TARGET_ARCH),arm)
libc_common_src_files += \
bionic/eabi.c \
bionic/bionic_clone.c \
arch-arm/bionic/__get_pc.S \
arch-arm/bionic/__get_sp.S \
@ -325,6 +324,7 @@ libc_common_src_files += \
arch-arm/bionic/_setjmp.S \
arch-arm/bionic/atomics_arm.S \
arch-arm/bionic/clone.S \
arch-arm/bionic/eabi.c \
arch-arm/bionic/ffs.S \
arch-arm/bionic/kill.S \
arch-arm/bionic/libgcc_compat.c \
@ -421,7 +421,6 @@ libc_common_src_files += \
string/strncmp.c \
string/memcmp.c \
string/strlen.c \
bionic/eabi.c \
bionic/pthread.c \
bionic/pthread-rwlocks.c \
bionic/pthread-timers.c \
@ -490,6 +489,10 @@ else
libc_common_cflags += -DANDROID_SMP=0
endif
# Needed to access private/__dso_handle.S from
# crtbegin_xxx.S and crtend_xxx.S
#
libc_crt_target_cflags += -I$(LOCAL_PATH)/private
# Define some common includes
# ========================================================
@ -504,10 +507,17 @@ libc_common_c_includes := \
# executables)
# ==========================================================================
ifeq ($(TARGET_ARCH),x86)
# we only need begin_so/end_so for x86, since it needs an appropriate .init
# section in the shared library with a function to call all the entries in
# .ctors section. ARM uses init_array, and does not need the function.
ifneq ($(filter arm x86,$(TARGET_ARCH)),)
# ARM and x86 need crtbegin_so/crtend_so.
#
# For x86, the .init section must point to a function that calls all
# entries in the .ctors section. (on ARM this is done through the
# .init_array section instead).
#
# For both platforms, the .fini_array section must point to a function
# that will call __cxa_finalize(&__dso_handle) in order to ensure that
# static C++ destructors are properly called on dlclose().
#
GEN := $(TARGET_OUT_STATIC_LIBRARIES)/crtbegin_so.o
$(GEN): $(LOCAL_PATH)/arch-$(TARGET_ARCH)/bionic/crtbegin_so.S
@mkdir -p $(dir $@)

9
libc/arch-arm/bionic/crtbegin_dynamic.S
View File

@ -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
@ -64,12 +64,6 @@ _start:
.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"

55
libc/arch-arm/bionic/crtbegin_so.S Normal file
View File

@ -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"

8
libc/arch-arm/bionic/crtbegin_static.S
View File

@ -64,12 +64,6 @@ _start:
.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"

38
libc/arch-arm/bionic/crtend_so.S Normal file
View File

@ -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

16
libc/bionic/eabi.c → libc/arch-arm/bionic/eabi.c
View File

@ -30,7 +30,21 @@
extern int __cxa_atexit(void (*)(void*), void*, void* );
void* __dso_handle = 0;
/* 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

6
libc/arch-sh/bionic/crtbegin_dynamic.S
View File

@ -1,5 +1,5 @@
/*
* Copyright (C) 2009 The Android Open Source Project
* Copyright (C) 2009-2010 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@ -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
@ -93,3 +93,5 @@ __FINI_ARRAY__:
.globl __CTOR_LIST__
__CTOR_LIST__:
.long -1
#include "__dso_handle.S"

9
libc/arch-sh/bionic/crtbegin_static.S
View File

@ -1,5 +1,5 @@
/*
* Copyright (C) 2009 The Android Open Source Project
* Copyright (C) 2009-2010 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@ -68,12 +68,6 @@ _start:
.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__:
@ -94,3 +88,4 @@ __FINI_ARRAY__:
__CTOR_LIST__:
.long -1
#include "__dso_handle.S"

3
libc/arch-x86/bionic/crtbegin_dynamic.S
View File

@ -30,7 +30,7 @@
.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
@ -94,3 +94,4 @@ __FINI_ARRAY__:
__CTOR_LIST__:
.long -1
#include "__dso_handle.S"

10
libc/arch-x86/bionic/crtbegin_so.S
View File

@ -1,3 +1,10 @@
# This function is to be called when the shared library
# is unloaded through dlclose()
_on_dlclose:
lea __dso_handle, %eax
call __cxa_finalize
ret
/* we put the _init() function here in case the user files for the shared
* libs want to drop things into .init section.
* We then will call our ctors from crtend_so.o */
@ -20,6 +27,7 @@ __INIT_ARRAY__:
.globl __FINI_ARRAY__
__FINI_ARRAY__:
.long -1
.long _on_dlclose
.section .ctors, "aw"
.align 4
@ -27,3 +35,5 @@ __FINI_ARRAY__:
.globl __CTOR_LIST__
__CTOR_LIST__:
.long -1
#include "__dso_handle.S"

7
libc/arch-x86/bionic/crtbegin_static.S
View File

@ -67,12 +67,6 @@ _start:
.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__:
@ -93,3 +87,4 @@ __FINI_ARRAY__:
__CTOR_LIST__:
.long -1
#include "__dso_handle.S"

37
libc/private/__dso_handle.S Normal file
View File

@ -0,0 +1,37 @@
/*
* 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.
*/
# The __dso_handle global variable is used by static
# C++ constructors and destructors in the binary.
# See http://www.codesourcery.com/public/cxx-abi/abi.html#dso-dtor
#
.section .bss
.align 4
.globl __dso_handle
__dso_handle:
.long 0