Bisection Bug Search is a tool for finding compiler optimizations bugs. It accepts a program which exposes a bug by producing incorrect output and expected output for the program. It then attempts to narrow down the issue to a single method and optimization pass under the assumption that interpreter is correct.
Given methods in order M0..Mn finds smallest i such that compiling Mi and interpreting all other methods produces incorrect output. Then, given ordered optimization passes P0..Pl, finds smallest j such that compiling Mi with passes P0..Pj-1 produces expected output and compiling Mi with passes P0..Pj produces incorrect output. Prints Mi and Pj.
There are two supported invocation modes:
Regular invocation, dalvikvm command is constructed internally:
./bisection_search.py -cp classes.dex --expected-output out_int --class Test
Raw-cmd invocation, dalvikvm command is accepted as an argument.
Extra dalvikvm arguments will be placed on second position in the command by default. {ARGS} tag can be used to specify a custom position.
If used in device mode, the command has to exec a dalvikvm instance. Bisection will fail if pid of the process started by raw-cmd is different than pid of runtime.
./bisection_search.py --raw-cmd='run.sh -cp classes.dex Test' --expected-retcode SUCCESS
./bisection_search.py --raw-cmd='/bin/sh art {ARGS} -cp classes.dex Test' --expected-retcode SUCCESS
Help:
bisection_search.py [-h] [-cp CLASSPATH] [--class CLASSNAME] [--lib LIB]
[--dalvikvm-option [OPT [OPT ...]]] [--arg [ARG [ARG ...]]]
[--image IMAGE] [--raw-cmd RAW_CMD]
[--64] [--device] [--device-serial DEVICE_SERIAL]
[--expected-output EXPECTED_OUTPUT]
[--expected-retcode {SUCCESS,TIMEOUT,ERROR}]
[--check-script CHECK_SCRIPT] [--logfile LOGFILE] [--cleanup]
[--timeout TIMEOUT] [--verbose]
Tool for finding compiler bugs. Either --raw-cmd or both -cp and --class are required.
optional arguments:
-h, --help show this help message and exit
dalvikvm command options:
-cp CLASSPATH, --classpath CLASSPATH classpath
--class CLASSNAME name of main class
--lib LIB lib to use, default: libart.so
--dalvikvm-option [OPT [OPT ...]] additional dalvikvm option
--arg [ARG [ARG ...]] argument passed to test
--image IMAGE path to image
--raw-cmd RAW_CMD bisect with this command, ignore other command options
bisection options:
--64 x64 mode
--device run on device
--device-serial DEVICE_SERIAL device serial number, implies --device
--expected-output EXPECTED_OUTPUT file containing expected output
--expected-retcode {SUCCESS,TIMEOUT,ERROR} expected normalized return code
--check-script CHECK_SCRIPT script comparing output and expected output
--logfile LOGFILE custom logfile location
--cleanup clean up after bisecting
--timeout TIMEOUT if timeout seconds pass assume test failed
--verbose enable verbose output