🚀 go-pugleaf

In article <4fkpos$4nu@fsuj01.rz.uni-jena.de> mwj@rz.uni-jena.de (Johannes Waldmann) writes:

> From: mwj@rz.uni-jena.de (Johannes Waldmann)
> Newsgroups: gnu.gcc.help
> Date: 11 Feb 1996 13:08:44 GMT
> Organization: Friedrich-Schiller-University Jena, Germany
> 
> Perhaps this is a bit naive, but here goes:
> 
> 	Can I use gcc's back-end to optimize assembler programs?
> 
> Possibly, assembler code could be transformed into RTL,
> then gcc could read that, and proceed as if it came from
> the expansion of a syntax tree.

No. The RTL chain contains only a portion of the compilation state.

> Are gcc's machine descriptions `invertible', i. e. can they be
> used to automatically generate .rtl from .s?

Again, no: machine descriptions map the RTL gcc generates for that 
particular target into assembly language, but the assembler of
a given target is usually not covered completely.

> Can I make the gcc back-end _start_ at a certain stage 
> of the compilation?  Something like:
> 	gcc -dr foo.c;  gcc --start-with-r foo.c.rtl

In theory. As long as you reproduce the state of all GCC's data structures 
necessary from that point on.

> By the way, is such a foo.c.rtl fully self-contained?

Not a chanche, RTL dumps are intended for debugging the compiler and
machine descriptions, not for re-entering GCC.

> Has someone already done such things? How much work would it require?

A fair amount.

> Would it be worth it?

For optimizing assembler, I would say no. For other applications, maybe.

-- 
				Maurizio Vitale
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