docs/CommandGuide/bugpoint.rst

bugpoint - automatic test case reduction tool
=============================================

SYNOPSIS
--------

**bugpoint** [*options*] [*input LLVM ll/bc files*] [*LLVM passes*] **--args**
*program arguments*

DESCRIPTION
-----------

**bugpoint** narrows down the source of problems in LLVM tools and passes.  It
can be used to debug three types of failures: optimizer crashes, miscompilations
by optimizers, or bad native code generation (including problems in the static
and JIT compilers).  It aims to reduce large test cases to small, useful ones.
For more information on the design and inner workings of **bugpoint**, as well as
advice for using bugpoint, see :doc:`/Bugpoint` in the LLVM
distribution.

OPTIONS
-------

**--additional-so** *library*

 Load the dynamic shared object *library* into the test program whenever it is
 run.  This is useful if you are debugging programs which depend on non-LLVM
 libraries (such as the X or curses libraries) to run.

**--append-exit-code**\ =\ *{true,false}*

 Append the test programs exit code to the output file so that a change in exit
 code is considered a test failure. Defaults to false.

**--args** *program args*

 Pass all arguments specified after **--args** to the test program whenever it runs.
 Note that if any of the *program args* start with a "``-``", you should use:

 .. code-block:: bash

      bugpoint [bugpoint args] --args -- [program args]

 The "``--``" right after the **--args** option tells **bugpoint** to consider
 any options starting with "``-``" to be part of the **--args** option, not as
 options to **bugpoint** itself.

**--tool-args** *tool args*

 Pass all arguments specified after **--tool-args** to the LLVM tool under test
 (**llc**, **lli**, etc.) whenever it runs.  You should use this option in the
 following way:

 .. code-block:: bash

      bugpoint [bugpoint args] --tool-args -- [tool args]

 The "``--``" right after the **--tool-args** option tells **bugpoint** to
 consider any options starting with "``-``" to be part of the **--tool-args**
 option, not as options to **bugpoint** itself. (See **--args**, above.)

**--safe-tool-args** *tool args*

 Pass all arguments specified after **--safe-tool-args** to the "safe" execution
 tool.

**--gcc-tool-args** *gcc tool args*

 Pass all arguments specified after **--gcc-tool-args** to the invocation of
 **gcc**.

**--opt-args** *opt args*

 Pass all arguments specified after **--opt-args** to the invocation of **opt**.

**--disable-{dce,simplifycfg}**

 Do not run the specified passes to clean up and reduce the size of the test
 program. By default, **bugpoint** uses these passes internally when attempting to
 reduce test programs.  If you're trying to find a bug in one of these passes,
 **bugpoint** may crash.

**--enable-valgrind**

 Use valgrind to find faults in the optimization phase. This will allow
 bugpoint to find otherwise asymptomatic problems caused by memory
 mis-management.

**-find-bugs**

 Continually randomize the specified passes and run them on the test program
 until a bug is found or the user kills **bugpoint**.

**-help**

 Print a summary of command line options.

**--input** *filename*

 Open *filename* and redirect the standard input of the test program, whenever
 it runs, to come from that file.

**--load** *plugin*

 Load the dynamic object *plugin* into **bugpoint** itself.  This object should
 register new optimization passes.  Once loaded, the object will add new command
 line options to enable various optimizations.  To see the new complete list of
 optimizations, use the **-help** and **--load** options together; for example:


 .. code-block:: bash

      bugpoint --load myNewPass.so -help

**--mlimit** *megabytes*

 Specifies an upper limit on memory usage of the optimization and codegen. Set
 to zero to disable the limit.

**--output** *filename*

 Whenever the test program produces output on its standard output stream, it
 should match the contents of *filename* (the "reference output"). If you
 do not use this option, **bugpoint** will attempt to generate a reference output
 by compiling the program with the "safe" backend and running it.

**--run-{int,jit,llc,custom}**

 Whenever the test program is compiled, **bugpoint** should generate code for it
 using the specified code generator.  These options allow you to choose the
 interpreter, the JIT compiler, the static native code compiler, or a
 custom command (see **--exec-command**) respectively.

**--safe-{llc,custom}**

 When debugging a code generator, **bugpoint** should use the specified code
 generator as the "safe" code generator. This is a known-good code generator
 used to generate the "reference output" if it has not been provided, and to
 compile portions of the program that as they are excluded from the testcase.
 These options allow you to choose the
 static native code compiler, or a custom command, (see **--exec-command**)
 respectively. The interpreter and the JIT backends cannot currently
 be used as the "safe" backends.

**--exec-command** *command*

 This option defines the command to use with the **--run-custom** and
 **--safe-custom** options to execute the bitcode testcase. This can
 be useful for cross-compilation.

**--compile-command** *command*

 This option defines the command to use with the **--compile-custom**
 option to compile the bitcode testcase. The command should exit with a
 failure exit code if the file is "interesting" and should exit with a
 success exit code (i.e. 0) otherwise (this is the same as if it crashed on
 "interesting" inputs).

 This can be useful for
 testing compiler output without running any link or execute stages. To
 generate a reduced unit test, you may add CHECK directives to the
 testcase and pass the name of an executable compile-command script in this form:

 .. code-block:: sh

      #!/bin/sh
      llc "$@"
      not FileCheck [bugpoint input file].ll < bugpoint-test-program.s

 This script will "fail" as long as FileCheck passes. So the result
 will be the minimum bitcode that passes FileCheck.

**--safe-path** *path*

 This option defines the path to the command to execute with the
 **--safe-{int,jit,llc,custom}**
 option.

**--verbose-errors**\ =\ *{true,false}*

 The default behavior of bugpoint is to print "<crash>" when it finds a reduced
 test that crashes compilation. This flag prints the output of the crashing
 program to stderr. This is useful to make sure it is the same error being
 tracked down and not a different error that happens to crash the compiler as
 well. Defaults to false.

EXIT STATUS
-----------

If **bugpoint** succeeds in finding a problem, it will exit with 0.  Otherwise,
if an error occurs, it will exit with a non-zero value.

SEE ALSO
--------

opt|opt