NDK JNI so 库崩溃分析
JNI开发中，常遇到so库崩溃。我们可以采用以下几种方法定位问题。
通常崩溃log会打印出寄存器信息和堆栈信息。
目录下面有如下工具。
首先要根据不同的平台架构来找到对应的工具
arm、x86_64、或者aarch64、i686
先大概看看各个工具功能：as是汇编编译器、ar用于创建和修改档案文件（.a就是一种档案文件）、ld链接器、nm 列出程序文件的符号和符号在内存中的地址（符合包括函数名和变量名）
我们用来定位问题常用的是两个：
addr2line 用来找到地址对应的函数和源文件名和行号、objdump 显示程序文件相关内容和对程序文件进行反汇编。
addr2line -C -f -e xxx.so 地址 地址
Convert addresses into line number/file name pairs.
If no addresses are specified on the command line, they will be read from stdin
The options are:
@
-a --addresses Show addresses
-b --target=
-e --exe=
-i --inlines Unwind inlined functions 解开内联函数
-j --section=
-p --pretty-print Make the output easier to read for humans 让输出对人类更可读
-s --basenames Strip directory names 去除目录名
-f --functions Show function names
-C --demangle[=style] Demangle function names 解码函数名
-h --help Display this information
-v --version Display the program's version
arm-linux-androideabi-objdump.exe -dx XX.so > xx.txt
反汇编
Display information from object
At least one of the following switches must be given:
-a, --archive-headers Display archive header information
-f, --file-headers Display the contents of the overall file header
-p, --private-headers Display object format specific file header contents
-P, --private=OPT,OPT... Display object format specific contents
-h, --[section-]headers Display the contents of the section headers
-x, --all-headers Display the contents of all headers
-d, --disassemble Display assembler contents of executable sections
-D, --disassemble-all Display assembler contents of all sections
-S, --source Intermix source code with disassembly
-s, --full-contents Display the full contents of all sections requested
-g, --debugging Display debug information in object file
-e, --debugging-tags Display debug information using ctags style
-G, --stabs Display (in raw form) any STABS info in the file
-W[lLiaprmfFsoRt] or
--dwarf[=rawline,=decodedline,=info,=abbrev,=pubnames,=aranges,=macro,=frames,
=frames-interp,=str,=loc,=Ranges,=pubtypes,
=gdb_index,=trace_info,=trace_abbrev,=trace_aranges,
=addr,=cu_index]
Display DWARF info in the file
-t, --syms Display the contents of the symbol table(s)
-T, --dynamic-syms Display the contents of the dynamic symbol table
-r, --reloc Display the relocation entries in the file
-R, --dynamic-reloc Display the dynamic relocation entries in the file
@
-v, --version Display this program's version number
-i, --info List object formats and architectures supported
-H, --help Display this information
The following switches are optional:
-b, --target=BFDNAME Specify the target object format as BFDNAME
-m, --architecture=MACHINE Specify the target architecture as MACHINE
-j, --section=NAME Only display information for section NAME
-M, --disassembler-options=OPT Pass text OPT on to the disassembler
-EB --endian=big Assume big endian format when disassembling
-EL --endian=little Assume little endian format when disassembling
--file-start-context Include context from start of file (with -S)
-I, --include=DIR Add DIR to search list for source files
-l, --line-numbers Include line numbers and filenames in output
-F, --file-offsets Include file offsets when displaying information
-C, --demangle[=STYLE] Decode mangled/processed symbol names
The STYLE, if specified, can be `auto', `gnu',
`lucid', `arm', `hp', `edg', `gnu-v3', `java'
or `gnat'
-w, --wide Format output for more than 80 columns
-z, --disassemble-zeroes Do not skip blocks of zeroes when disassembling
--start-address=ADDR Only process data whose address is >= ADDR
--stop-address=ADDR Only process data whose address is <= ADDR
--prefix-addresses Print complete address alongside disassembly
--[no-]show-raw-insn Display hex alongside symbolic disassembly
--insn-width=WIDTH Display WIDTH bytes on a single line for -d
--adjust-vma=OFFSET Add OFFSET to all displayed section addresses
--special-syms Include special symbols in symbol dumps
--prefix=PREFIX Add PREFIX to absolute paths for -S
--prefix-strip=LEVEL Strip initial directory names for -S
--dwarf-depth=N Do not display DIEs at depth N or greater
--dwarf-start=N Display DIEs starting with N, at the same depth
or deeper
--dwarf-check Make additional dwarf internal consistency checks.
ndk-stack -sym E:\dev_code\Sosomap-old\Sosomap-jni\obj\local\armeabi -dump D:\android-ndk-r9b-windows-x86\txmap_log.txt
-sym为带符号表的so路径， -dump为crash的堆栈信息，必须包含：********************
输出所有导出函数
arm-linux-androideabi-readelf.exe -a XX.so > xx.txt
输出.a内所有导出函数。
arm-linux-androideabi-ar.exe -t xx.a > xx.txt
arm-linux-androideabi-nm.exe xx.a > xx.txt