22a6a058c7
arm32 has two special APIs to find exidx exception handling info, dl_unwind_find_exidx and __gnu_Unwind_Find_exdix. The two functions have identical behavior and function prototypes. libgcc's arm32 unwinder calls __gnu_Unwind_Find_exdix, whereas LLVM's libunwind previously called __gnu_Unwind_Find_exdix, but switched to dl_unwind_find_exidx as a result of three patches (D30306, D30681, D39468). In Bionic, for dynamic linking, __gnu_Unwind_Find_exdix in libc.so calls dl_unwind_find_exidx in libdl.so. For static executables, though, __gnu_Unwind_Find_exdix in libc.a used the __exidx_* symbols, while dl_unwind_find_exidx in libdl.a(libdl_static.o) was a return-0 no-op. To fix the LLVM unwinder, replace the no-op dl_unwind_find_exidx in libdl.a with a real function in libc.a(exidx_static.o), and have the GNU function call the dl function for more consistency with dynamic linking. dl_iterate_phdr follows a similar pattern, where the function exists in libc.a and libdl.so (not libc.so or libdl.a). This change makes unwinding work with an updated libunwind_llvm on arm32, and it helps to allow unwinding in static executables without libdl.a. Bug: https://github.com/android/ndk/issues/1094 Bug: http://b/141485154 Test: NDK tests, bionic unit tests Change-Id: Ieeeb9b39a0e28544e21f9afe6fe51ef10d7c828c
53 lines
2.1 KiB
C
53 lines
2.1 KiB
C
/*
|
|
* 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 <link.h>
|
|
|
|
/* Find the .ARM.exidx section (which in the case of a static executable
|
|
* can be identified through its start and end symbols), and return its
|
|
* beginning and number of entries to the caller. Note that for static
|
|
* executables we do not need to use the value of the PC to find the
|
|
* EXIDX section.
|
|
*/
|
|
|
|
struct exidx_entry {
|
|
uint32_t key;
|
|
uint32_t value;
|
|
};
|
|
|
|
extern struct exidx_entry __exidx_end;
|
|
extern struct exidx_entry __exidx_start;
|
|
|
|
_Unwind_Ptr dl_unwind_find_exidx(_Unwind_Ptr pc __attribute__((unused)), int* pcount) {
|
|
*pcount = (&__exidx_end - &__exidx_start);
|
|
return (_Unwind_Ptr)&__exidx_start;
|
|
}
|
|
|
|
_Unwind_Ptr __gnu_Unwind_Find_exidx(_Unwind_Ptr pc, int *pcount) {
|
|
return dl_unwind_find_exidx(pc, pcount);
|
|
}
|