llvm dev - Jul 2011 - [LLVMdev] getFunction() of DISubprogram return 0?

Hi,

I'd like to get the Function* that is described by a DISubprogram. I 
found this method getFunction() in the class. However, when I use it in 
my code, the function always returns 0. I tried to dig into it and saw 
that a mysterious number 16 is used in getFunctionField(16). I'm 
wondering if my failure of the function was caused by my incorrect use, 
e.g., without fulfilling necessary assumptions by running some passes 
first, or by that this number was planned but not implemented yet.

Thanks.
Lu

Hi,
On Jul 22, 2011, at 6:37 PM, Lu Zhao wrote:
> Hi,
> 
> I'd like to get the Function* that is described by a DISubprogram. I 
> found this method getFunction() in the class. However, when I use it in 
> my code, the function always returns 0. I tried to dig into it and saw 
> that a mysterious number 16 is used in getFunctionField(16). I'm 
> wondering if my failure of the function was caused by my incorrect use, 
> e.g., without fulfilling necessary assumptions by running some passes 
> first, or by that this number was planned but not implemented yet.
It is likely that your front end did not emit include Function * while emitting
debugging information entry for a subprogram. Initially, Function * was not part
of DISubprogram.

If you wonder how do you determine field number 16 is used for Function * then
see, http://llvm.org/docs/SourceLevelDebugging.html#format_subprograms


-
Devang