Re: GNU Assembler Start of Function & basic block

[Nick Clifton <nickc at redhat dot com>]

Hi Balaji,

> 	I am doing it through
> assembler because I want to put specalized control instructions that I
> have created to explain the register usage to the processor. These
> instructions give information about register usage and liveness
> information to the processor. 

This is definitely something that can only be done in the compiler, not the 
assembler.

> 	Now, can these specialized instructions be conveyed in the
> machine description of GCC? I have looked through the MD documentation
> in the internals document and I hvae not found a way to do so.   

Yes.  Ask on the gcc mailing lists about this.  Also have a look at how UNSPEC 
patterns are used for various architectures.  Plus you may not need to put this 
into the machine description.  You may be able to include the code to generate 
the instructions in the backend's function prologue and epilogue generating 
code.  You may also be able to use some of the compiler's support for the GCOV 
tool in order to add per-basic-block instructions.

Cheers
  Nick