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Change the way we code-gen simple for loops. 
For a for loop with a single argument and no phasers, we can generate
inline code that calls .pull-one and invokes the block. This will turn
megamorphic callsites inside of sink-all into typically monomorphic
ones, which should enable the specializer - at least, once it has had
some tweaks - to do a better job.
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@jnthn
jnthn committed Jun 15, 2017
1 parent 98b9eae commit 9b0b9ef
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Showing 3 changed files with 111 additions and 8 deletions.
113 changes: 108 additions & 5 deletions src/Perl6/Actions.nqp
View file
Expand Up @@ -508,6 +508,95 @@ register_op_desugar('p6for', -> $qast {
QAST::Op.new( :op<callmethod>, :name($qast.sunk ?? 'sink' !! 'eager'), $call )
);
});
register_op_desugar('p6forstmt', -> $qast {
my $for-target-name := QAST::Node.unique('for_target');
my $for-target := QAST::Op.new(
:op('bind'),
QAST::Var.new( :name($for-target-name), :scope('local'), :decl('var') ),
$qast[0]
);

my $iterator-name := QAST::Node.unique('for_iterator');
my $iterator := QAST::Op.new(
:op('bind'),
QAST::Var.new( :name($iterator-name), :scope('local'), :decl('var') ),
QAST::Op.new(
:op('callmethod'), :name('iterator'),
QAST::Op.new(
:op('if'),
QAST::Op.new(
:op('iscont'),
QAST::Var.new( :name($for-target-name), :scope('local') )
),
QAST::Op.new(
:op('callstatic'), :name('&infix:<,>'),
QAST::Var.new( :name($for-target-name), :scope('local') )
),
QAST::Var.new( :name($for-target-name), :scope('local') )
)));

my $iteration-end-name := QAST::Node.unique('for_iterationend');
my $iteration-end := QAST::Op.new(
:op('bind'),
QAST::Var.new( :name($iteration-end-name), :scope('local'), :decl('var') ),
QAST::WVal.new( :value($qast.ann('IterationEnd')) )
);

my $block-name := QAST::Node.unique('for_block');
my $block := QAST::Op.new(
:op('bind'),
QAST::Var.new( :name($block-name), :scope('local'), :decl('var') ),
$qast[1]
);

my $iter-val-name := QAST::Node.unique('for_iterval');
my $loop := QAST::Op.new(
:op('until'),
QAST::Op.new(
:op('eqaddr'),
QAST::Op.new(
:op('decont'),
QAST::Op.new(
:op('bind'),
QAST::Var.new( :name($iter-val-name), :scope('local'), :decl('var') ),
QAST::Op.new(
:op('callmethod'), :name('pull-one'),
QAST::Var.new( :name($iterator-name), :scope('local') )
)
)
),
QAST::Var.new( :name($iteration-end-name), :scope('local') )
),
QAST::Op.new(
:op('call'),
QAST::Var.new( :name($block-name), :scope('local') ),
QAST::Var.new( :name($iter-val-name), :scope('local') )
));
if $qast[2] {
$loop.push($qast[2]);
}

QAST::Stmts.new(
$for-target,
$iterator,
$iteration-end,
$block,
$loop,
QAST::WVal.new( :value($qast.ann('Nil')) )
)
});

sub can-use-p6forstmt($block) {
my $past_block := $block.ann('past_block');
my $count := $past_block.ann('count');
return 0 unless nqp::isconcrete($count) && $count == 1;
my $code := $block.ann('code_object');
my $block_type := $*W.find_symbol(['Block'], :setting-only);
return 1 unless nqp::istype($code, $block_type);
my $p := nqp::getattr($code, $block_type, '$!phasers');
nqp::isnull($p) ||
!(nqp::existskey($p, 'FIRST') || nqp::existskey($p, 'LAST') || nqp::existskey($p, 'NEXT'))
}

sub monkey_see_no_eval($/) {
my $msne := $*LANG.pragma('MONKEY-SEE-NO-EVAL');
Expand Down Expand Up @@ -1388,7 +1477,12 @@ class Perl6::Actions is HLL::Actions does STDActions {
);
$past[2].sunk(1);
my $sinkee := $past[0];
$past.annotate('statement_level', -> { UNWANTED($sinkee, 'force for mod') });
$past.annotate('statement_level', -> {
UNWANTED($sinkee, 'force for mod');
$fornode.op('p6forstmt') if can-use-p6forstmt($fornode[1]);
$fornode.annotate('IterationEnd', $*W.find_symbol(['IterationEnd']));
$fornode.annotate('Nil', $*W.find_symbol(['Nil']));
});
}
else {
$past := QAST::Op.new($cond, $past, :op(~$ml<sym>), :node($/) );
Expand Down Expand Up @@ -1780,7 +1874,14 @@ class Perl6::Actions is HLL::Actions does STDActions {
}
$past[2].sunk(1);
my $sinkee := $past[0];
$past.annotate('statement_level', -> { UNWANTED($sinkee,'force for') });
$past.annotate('statement_level', -> {
UNWANTED($sinkee,'force for');
if can-use-p6forstmt($fornode[1]) {
$fornode.op('p6forstmt');
$fornode.annotate('IterationEnd', $*W.find_symbol(['IterationEnd']));
$fornode.annotate('Nil', $*W.find_symbol(['Nil']));
}
});
make $past;
}

Expand Down Expand Up @@ -8122,12 +8223,14 @@ class Perl6::Actions is HLL::Actions does STDActions {
sub add_signature_binding_code($block, $sig_obj, @params) {
# Set arity.
my int $arity := 0;
my int $count := 0;
for @params {
last if $_<optional> || $_<named_names> ||
$_<pos_slurpy> || $_<pos_onearg> || $_<named_slurpy>;
$arity := $arity + 1;
last if $_<named_names> || $_<pos_slurpy> || $_<pos_onearg> || $_<named_slurpy>;
$arity := $arity + 1 unless $_<optional>;
$count := $count + 1;
}
$block.arity($arity);
$block.annotate('count', $count);

# Consider using the VM binder on backends where it will work out
# (e.g. we can get the same errors).
Expand Down
3 changes: 0 additions & 3 deletions src/core/Mu.pm
View file
Expand Up @@ -3,9 +3,6 @@ my class X::Method::NotFound { ... }
my class X::Method::InvalidQualifier { ... }
my class X::Attribute::Required { ... }

# We use a sentinel value to mark the end of an iteration.
my constant IterationEnd = nqp::create(Mu);

my class Mu { # declared in BOOTSTRAP

method self { self }
Expand Down
3 changes: 3 additions & 0 deletions src/core/core_prologue.pm
View file
Expand Up @@ -25,6 +25,9 @@ my class IterationBuffer is repr('VMArray') { ... }
my constant Empty = nqp::p6bindattrinvres(nqp::create(Slip),
List, '$!reified', nqp::create(IterationBuffer));

# We use a sentinel value to mark the end of an iteration.
my constant IterationEnd = nqp::create(Mu);

# To allow passing of nqp::hash without being HLLized, we create a HLL class
# with the same low level REPR as nqp::hash.
my class Rakudo::Internals::IterationSet is repr('VMHash') { }
Expand Down

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