as/ld silently creates programs with undefined references/symbols

[Nick Clifton]

Hi Russell, Hi Richard,

> The Linux kernel is an example of a build system which parses the output
> from "nm" in order to build an internal symbol table.  As I highlighted
> before, this whole "mapping symbol" business is severly affecting the
> usefulness of the toolchain and it is imperative that this problem is
> fully resolved before binutils 2.16.

I have a prototype solution to this problem, but I would like more input 
from anyone who is interested.  My idea is to provide a new function in 
the BFD ABI:

   bfd_boolean bfd_is_target_special_symbol (bfd *, asymbol *);

This function will determine if a given symbol symbol in a symbol table 
is "special" in some target specific sense.  I decided that this would 
be a safer approach, rather than adding code to make BFD produce 
abbreviated symbol tables with the special symbols stripped.  In my 
experience modifying symbol tables in BFD is very tricky.

I am attaching a proof of concept patch which applied to today's 
mainline binutils sources.  It uses this new function to implement a new 
command line switch to nm: "--skip-special" which will successfully 
remove any of the ARM mapping symbols from its output.

Does anyone have any comments on this proposed solution ?  One thing I 
wondered was whether bfd_is_target_special_symbol() should return a 
string instead of a boolean.  It could return a NULL pointer for normal 
symbols and some kind of description for special symbols.  Then the 
caller could decide to print this description if it was displaying the 
symbol to a user.

Cheers
   Nick


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