dabeaz/bitey

bitey's Issues

segfault if py_module gets garbage collected

I was working on an IPython extension which provides a cell magic for running C code via bitey, e.g.:

In [4]: %load_ext biteymagic

In [5]: %%bitey
   ...: int life() { return 42; }
   ...: 

In [6]: life()
Out[6]: 42

However I was running into random segfaults, often after running %timeit or similar, indicating that garbage collection was likely to blame. To cut to the chase, the issue was because I called bitey.loader.build_module to build a module, extracted the functions into the current namespace, but never saved the built module in sys.modules. When the module was garbage collected (and hence _llvm_engine/_llvm_module get deleted).... BOOM!

To fix the bug, either of the following would be sufficient:

1. I could add the module to sys.modules. In this case, I'd suggest a short note in the docstring.
2. Keep a reference in the python wrapper function object to the execution engine, i.e. set _llvm_engine and _llvm_module as attributes.

Patch to make biteymagic work w/o spawning CLI window on Windows

While executing with biteymagic on Windows, command line window pops (calling clang action) which can be improved (disabled) by adding couple of lines:

--- biteymagic.bak  2012-11-10 22:34:43.406173200 +0100
+++ biteymagic.py   2012-11-10 22:30:38.421798200 +0100
@@ -75,10 +75,19 @@

         if not os.path.exists(o_path):
             try:
-                subprocess.check_output(['clang', '-c', '-emit-llvm'] +
-                                        line.split() + [c_name],
-                                        stderr=subprocess.STDOUT,
-                                        cwd=lib_dir)
+                if sys.platform == "win32":
+                    startupinfo = subprocess.STARTUPINFO()
+                    startupinfo.dwFlags |= subprocess.STARTF_USESHOWWINDOW
+                    subprocess.check_output(['clang', '-c', '-emit-llvm'] +
+                                            line.split() + [c_name],
+                                            stderr=subprocess.STDOUT,
+                                            cwd=lib_dir,
+                                            startupinfo=startupinfo)
+                else:
+                    subprocess.check_output(['clang', '-c', '-emit-llvm'] +
+                                            line.split() + [c_name],
+                                            stderr=subprocess.STDOUT,
+                                            cwd=lib_dir)
             except subprocess.CalledProcessError as e:
                 print(e.output, file=sys.stderr)
                 print("ERROR: command `%s` failed." %

can you give some benchmark?

I think many people will concern this.

Magic number checking code in loader.py seems wrong

In _check_magic you have:

magic = open(filename,"rb").read(4)

And then:

`elif magic == b'\x42\x43':``

It seems wrong to me. magic is 4 bytes long! You maybe meant:

elif magic[:2] == b'\x42\x43 ?

Without this change bitey examples don't run

python dumps core on "import fib" in "typical" install

The question is: which versions of the libs are required?

I've tried to install things in "dumb user" way (in Ubuntu 12.04):

sudo apt-get install clang llvm-dev python-llvm \  
&& git clone https://github.com/dabeaz/bitey.git \  
&& cd bitey \  
&& python ./setup.py build \  
&& sudo python ./setup.py install  \  
&& python  
Python 2.7.3 (default, Aug  1 2012, 05:16:07)   
[GCC 4.6.3] on linux2  
Type "help", "copyright", "credits" or "license" for more information.  
>>> import bitey  
>>> import fib  
Segmentation fault (core dumped)

where

$ cat fib.c
/* fib.c */
int fib(int n) {
    if (n < 3) {
       return 1;
    } else {
       return fib(n-1) + fib(n-2);
    }
}

$ file fib.*
fib.c: ASCII text
fib.o: LLVM bitcode

$ dpkg -l | egrep 'clang|llvm-dev|python-llvm'
ii  clang                                   3.0-6ubuntu3                            Low-Level Virtual Machine (LLVM), C language family frontend
ii  libclang-common-dev                     3.0-6ubuntu3                            clang library - Common development package
ii  llvm-dev                                2.9-7                                   Low-Level Virtual Machine (LLVM), libraries and headers
ii  python-llvm                             0.6+svn105-1                            Python bindings for LLVM

Any plans of llvmlite migration?

One of bitey dependencies - llvm-py (https://github.com/llvmpy/llvmpy) is now deprecated and is replaced with llvmlite (https://github.com/numba/llvmlite). Are there any plans to migrate bitey from llvm-py to llvmlite? Thanks!