[Cython] line tracing/profiling code objects

[Syam Gadde]

Hi all,

I tried using line tracing in conjunction with line_profiler/kernprof to 
attempt to see if line-based profiling works in Cython.  I think it's 
pretty close.  But I think the problem is that line_profiler is getting 
a different PyCodeObject when it wraps the function and when it actually 
gets the trace call.  It adds the initial code object to a map, and 
later when it gets the trace call, decides that the trace call is not 
something it needs to pay attention to because the new code object that 
it gets is not the same as the original one.

The first code object is created at function declaration by 
__Pyx_PyCode_New (called in__Pyx_InitCachedConstants) and is assigned to 
a variable __pyx_k_codeobj_NNN.  The second code object is created, 
essentially, during the first entry into the function (in 
__Pyx_TraceCall, via __Pyx_TraceSetupAndCall).  It seems that setting 
__pyx_frame_code to the initial code object before calling TraceCall() 
would fix this.

Is this easy to do?  I'd do it myself, but I'd need help figuring out 
how to get the name of the appropriate __pyx_k_codeobj_NNN variable from 
within FuncDefNode.generate_function_definitions(), which calls 
put_trace_call().

Thanks for your help...

-syam