Re^2: Perl 5 Compiler, Again!

[rurban]

flexvault:

There is an integrated compiler in perl5. And there are external compilers.

You will not easily see what the integrated compiler in perl5 does, but you see some result with B::Concise. All the ex-OPs there are optimized out already.

$ perl -MO=Concise -e'1+1'
3  <@> leave[1 ref] vKP/REFC ->(end)
1     <0> enter ->2
2     <;> nextstate(main 1 -e:1) v:{ ->3
-     <0> ex-const v ->3

E.g. 1=1 was constant folded here.

$ perl -MO=Concise -e'$a=1+$a'
8  <@> leave[1 ref] vKP/REFC ->(end)
1     <0> enter ->2
2     <;> nextstate(main 1 -e:1) v:{ ->3
7     <2> sassign vKS/2 ->8
5        <2> add[t1] sK/2 ->6
3           <$> const(IV 1) s ->4
-           <1> ex-rv2sv sK/1 ->5
4              <$> gvsv(*a) s ->5
-        <1> ex-rv2sv sKRM*/1 ->7
6           <$> gvsv(*a) s ->7

All the sv references rv2sv were optimized to direct gvsv accesses.

perlcc is the backend for 3 external compilers.