help regarding instruction scheduling in gcc - dfa(deterministic finite automaton)

Ben Elliston
Sun Oct 18 22:55:00 GMT 2009

On Sun, 2009-10-18 at 08:17 -0700, ddmetro wrote:

> 1. The starting point of generation of dfa(by reading md files) is
> 'genautomata.c'. When is the main() method of 'genautomata.c' called?

genautomata is compiled into the build/genautomata binary in your build
tree.  It is then invoked during the build process.

> 2. How and in what datastructure - is the dfa generated by 'genautomata.c'
> persisted between two method calls - one of main() method of genautomata.c
> and another of toplev_main() method of toplev.c 

The DFA is produced by genautomata and left behind in generated source
files in the build directory .. see insn-automata.c and insn-automata.h
as a starting point.  These files are then compiled into GCC.

Cheers, Ben

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