学习android5.0以后的ART虚拟机，看了看源码，比较头疼，决定通过动态调试的方式去学习。
Art虚拟机有一个dex2oat的可执行程序。就想到了通过gdb和gdbserver来debug这个dex2oat。
记录一下调试方法：
gdb运行在本地系统（windows/linux）
gdbserver运行在android真机/模拟器上（adb shell ls /system/bin查看是否有gdbserver，如果没有，可以从源代码prebuild文件夹中获取，也可以从ndk的文件中获取）
Ps：gdb和gdbserver的版本要一致，不然会出错的
一：“
1，准备工作：
1-1，在prebuild文件夹中找到gdb和gdbserver的可执行文件（ndk中也有）
1-2，把gdbserver 通过adb shell push进system/bin
1-3，把dex2oat需要的hello.jar给push到/data/test/中
2，通过adb在android模拟器中通过gdbserver关联相关的进程或者启动相关进程
2-1，gdbserver关联相关的进程 ： adb shell gdbserver :端口号1234--attach 进程pid
（进程pid可以通过adb shell ps查看，调试应用可以attach system_process（没有测试））
2-2，gdbserver启动相关的进程： adb shell gdbserver :端口号1234 dex2oat --dex-
file=/data/test/hello.jar --oat-file=/data/test/hello.dex
3，端口映射：
在本地命令行：adb forward tcp:1234 tcp:1234
4，进行gdb所在目录，启动gdb
4-1，cd /home/zero/android-5.0.0_r3.0.1/prebuilts/gcc/linux-x86/arm/arm-linux-androideabi-4.8/bin
4-2，./arm-linux-androideabi-gdb
5，进入了GDB以后：
5-1，（gdb）target remote localhost:1234 （连接目标）
5-2，（gdb）file /home/zero/android-5.0.0_r3.0.1/out/target/product/generic/symbols/system/bin/dex2oat （找到可执行文件dex2oat，都是在android源码的这个bin目录下的，一般的用户进程使用app_process）
5-3，（gdb）set solib-absolute-prefix /home/zero/android-5.0.0_r3.0.1/out/target/product/generic/symbols （不懂为什么要有这句）
5-4，（gdb）set solib-search-path /home/zero/android-5.0.0_r3.0.1/out/target/product/generic/symbols/system/lib （设置可函数路径？？）
6，设置断点 ，开始执行
6-1，（gdb）b main
6-2，（gdb） c
1，在源码目录执行：
1-1，source build/envsetup.sh
1-2,lunch full-eng
2，类似上面的gdbserver的启动和adb forward的端口映射
3,启动gdbclient
gdbclient dex2oat ：1234
4，设置断点，开始调试
envsetup.sh中关于gdbclient的源代码
<span style="font-size:18px;"># gdbclient now determines whether the user wants to debug a 32-bit or 64-bit
# executable, set up the approriate gdbserver, then invokes the proper host
# gdb.
function gdbclient()
{
local OUT_ROOT=$(get_abs_build_var PRODUCT_OUT)
local OUT_SYMBOLS=$(get_abs_build_var TARGET_OUT_UNSTRIPPED)
local OUT_SO_SYMBOLS=$(get_abs_build_var TARGET_OUT_SHARED_LIBRARIES_UNSTRIPPED)
local OUT_VENDOR_SO_SYMBOLS=$(get_abs_build_var TARGET_OUT_VENDOR_SHARED_LIBRARIES_UNSTRIPPED)
local OUT_EXE_SYMBOLS=$(get_symbols_directory)
local PREBUILTS=$(get_abs_build_var ANDROID_PREBUILTS)
local ARCH=$(get_build_var TARGET_ARCH)
local GDB
case "$ARCH" in
arm) GDB=arm-linux-androideabi-gdb;;
arm64) GDB=arm-linux-androideabi-gdb; GDB64=aarch64-linux-android-gdb;;
mips|mips64) GDB=mips64el-linux-android-gdb;;
x86) GDB=x86_64-linux-android-gdb;;
x86_64) GDB=x86_64-linux-android-gdb;;
*) echo "Unknown arch $ARCH"; return 1;;
esac
#参数1<span style="white-space:pre"> </span>
if [ "$OUT_ROOT" -a "$PREBUILTS" ]; then
local EXE="$1"
if [ "$EXE" ] ; then
EXE=$1
if [[ $EXE =~ ^[^/].* ]] ; then
EXE="system/bin/"$EXE
fi
else
EXE="app_process"
fi
#参数2<span style="white-space:pre"> </span>
local PORT="$2"
if [ "$PORT" ] ; then
PORT=$2
else
PORT=":5039"
fi
local PID="$3"
if [ "$PID" ] ; then
if [[ ! "$PID" =~ ^[0-9]+$ ]] ; then
PID=`pid $3`
if [[ ! "$PID" =~ ^[0-9]+$ ]] ; then
# that likely didn't work because of returning multiple processes
# try again, filtering by root processes (don't contain colon)
PID=`adb shell ps | \grep $3 | \grep -v ":" | awk '{print $2}'`
if [[ ! "$PID" =~ ^[0-9]+$ ]]
then
echo "Couldn't resolve '$3' to single PID"
return 1
else
echo ""
echo "WARNING: multiple processes matching '$3' observed, using root process"
echo ""
fi
fi
fi
adb forward "tcp$PORT" "tcp$PORT"
local USE64BIT="$(is64bit $PID)"
adb shell gdbserver$USE64BIT $PORT --attach $PID &
sleep 2
else
echo ""
echo "If you haven't done so already, do this first on the device:"
echo " gdbserver $PORT /system/bin/$EXE"
echo " or"
echo " gdbserver $PORT --attach <PID>"
echo ""
fi
OUT_SO_SYMBOLS=$OUT_SO_SYMBOLS$USE64BIT
OUT_VENDOR_SO_SYMBOLS=$OUT_VENDOR_SO_SYMBOLS$USE64BIT
echo >|"$OUT_ROOT/gdbclient.cmds" "set solib-absolute-prefix $OUT_SYMBOLS"
echo >>"$OUT_ROOT/gdbclient.cmds" "set solib-search-path $OUT_SO_SYMBOLS:$OUT_SO_SYMBOLS/hw:$OUT_SO_SYMBOLS/ssl/engines:$OUT_SO_SYMBOLS/drm:$OUT_SO_SYMBOLS/egl:$OUT_SO_SYMBOLS/soundfx:$OUT_VENDOR_SO_SYMBOLS:$OUT_VENDOR_SO_SYMBOLS/hw:$OUT_VENDOR_SO_SYMBOLS/egl"
echo >>"$OUT_ROOT/gdbclient.cmds" "source $ANDROID_BUILD_TOP/development/scripts/gdb/dalvik.gdb"
echo >>"$OUT_ROOT/gdbclient.cmds" "target remote $PORT"
# Enable special debugging for ART processes.
if [[ $EXE =~ (^|/)(app_process|dalvikvm)(|32|64)$ ]]; then
echo >> "$OUT_ROOT/gdbclient.cmds" "art-on"
fi
echo >>"$OUT_ROOT/gdbclient.cmds" ""
local WHICH_GDB=
# 64-bit exe found
if [ "$USE64BIT" != "" ] ; then
WHICH_GDB=$ANDROID_TOOLCHAIN/$GDB64
# 32-bit exe / 32-bit platform
elif [ "$(get_build_var TARGET_2ND_ARCH)" = "" ]; then
WHICH_GDB=$ANDROID_TOOLCHAIN/$GDB
# 32-bit exe / 64-bit platform
else
WHICH_GDB=$ANDROID_TOOLCHAIN_2ND_ARCH/$GDB
fi
gdbwrapper $WHICH_GDB "$OUT_ROOT/gdbclient.cmds" "$OUT_EXE_SYMBOLS/$EXE"
else
echo "Unable to determine build system output dir."
fi
}
</span>
Ps,1,通过脚本方便调试:
source XXXX
XXXX:
define envset target remote localhost:1234 file /home/zero/aa/android-5.0.0_r3.0.1/out/target/product/generic/symbols/system/bin/dex2oat set solib-absolute-prefix /home/zero/aa/android-5.0.0_r3.0.1/out/target/product/generic/symbols set solib-search-path /home/zero/aa/android-5.0.0_r3.0.1/out/target/product/generic/symbols/system/lib set breakpoint pending on end define argsSet set args --runtime-arg -classpath --runtime-arg hello.jar --instruction-set=arm --runtime-arg -Xrelocate --host --boot-image=/home/zero/aa/android-5.0.0_r3.0.1/out/target/product/generic/system/framework/boot.art --dex-file=hello.jar --oat-file=/home/zero/aa/android-5.0.0_r3.0.1/out/oatfiles/arm/hello.oat end define bb1 b frontend.cc:625 if method_idx==3 end
#!/bin/sh
CWD=`pwd`
export ANDROID_DATA="${CWD}/out/host/datadir/dalvik-cache/x86_64"
export ANDROID_ROOT="${CWD}/out/host/linux-x86"
BOOT_IMAGE="${CWD}/out/target/product/generic/system/framework/boot.art"
OUTPUT="${CWD}/out/oatfiles/arm"
#read x
#mkdir -p $OUTPUT
#mkdir -p $ANDROID_DATA
#exec gdb
exec gdb out/host/linux-x86/bin/dex2oat