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db4
Slava Pestov 2008-11-24 09:27:15 -06:00
parent ab689c098b
commit a4282139dc
1 changed files with 9 additions and 2 deletions
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11
vm/quotations.c
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@ -9,6 +9,10 @@ The non-optimizing compiler compiles a quotation at a time by concatenating
machine code chunks; prolog, epilog, call word, jump to word, etc. These machine
code chunks are generated from Factor code in core/cpu/.../bootstrap.factor.
Calls to words and constant quotations (referenced by conditionals and dips)
are direct jumps to machine code blocks. Literals are also referenced directly
without going through the literal table.
It actually does do a little bit of very simple optimization:
1) Tail call optimization.
@ -21,12 +25,15 @@ generated.
'if' and 'dispatch' conditionals are generated inline, instead of as a call to
the 'if' word.
4) When preceded by an array, calls to the 'declare' word are optimized out
4) When preceded by a quotation, calls to 'dip', '2dip' and '3dip' are
open-coded as retain stack manipulation surrounding a subroutine call.
5) When preceded by an array, calls to the 'declare' word are optimized out
entirely. This word is only used by the optimizing compiler, and with the
non-optimizing compiler it would otherwise just decrease performance to have to
push the array and immediately drop it after.
5) Sub-primitives are primitive words which are implemented in assembly and not
6) Sub-primitives are primitive words which are implemented in assembly and not
in the VM. They are open-coded and no subroutine call is generated. This
includes stack shufflers, some fixnum arithmetic words, and words such as tag,
slot and eq?. A primitive call is relatively expensive (two subroutine calls)