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Add a spesh plugin for return value decont
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Which both reduces the generated bytecode size for this operation, as
well as allowing us to provide optimized variants for a number of the
different cases that show up.
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@jnthn
jnthn committed Jul 9, 2018
1 parent 523ffae commit 8d65276
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Showing 2 changed files with 152 additions and 48 deletions.
123 changes: 75 additions & 48 deletions src/Perl6/Actions.nqp
View file
Expand Up @@ -807,69 +807,96 @@ register_op_desugar('p6var', -> $qast {
)
)
});
register_op_desugar('p6decontrv_internal', sub ($qast) {
my $result := QAST::Node.unique('result');
my $Scalar := QAST::WVal.new( :value(nqp::gethllsym('perl6', 'Scalar')) );
my $Iterable := QAST::WVal.new( :value(nqp::gethllsym('perl6', 'Iterable')) );
QAST::Stmt.new(
QAST::Op.new(
:op('bind'),
QAST::Var.new( :name($result), :scope('local'), :decl('var') ),
QAST::Op.new( :op('wantdecont'), $qast[0] )
),
QAST::Op.new(
# If it's a container...
:op('if'),
QAST::Op.new(
:op('if'),
{
my $is_moar;
register_op_desugar('p6decontrv_internal', -> $qast {
unless nqp::isconcrete($is_moar) {
$is_moar := nqp::getcomp('perl6').backend.name eq 'moar';
}
if $is_moar {
my $result := QAST::Node.unique('result');
QAST::Stmt.new(
QAST::Op.new(
:op('isconcrete_nd'),
QAST::Var.new( :name($result), :scope('local') )
:op('bind'),
QAST::Var.new( :name($result), :scope('local'), :decl('var') ),
QAST::Op.new( :op('wantdecont'), $qast[0] )
),
QAST::Op.new(
:op('iscont'),
QAST::Var.new( :name($result), :scope('local') )
:op('call'),
QAST::Op.new(
:op('speshresolve'),
QAST::SVal.new( :value('decontrv') ),
QAST::Var.new( :name($result), :scope('local') )
),
QAST::Var.new( :name($result), :scope('local') ),
)
),
# It's a container; is it an rw one?
QAST::Op.new(
:op('if'),
)
}
else {
my $result := QAST::Node.unique('result');
my $Scalar := QAST::WVal.new( :value(nqp::gethllsym('perl6', 'Scalar')) );
my $Iterable := QAST::WVal.new( :value(nqp::gethllsym('perl6', 'Iterable')) );
QAST::Stmt.new(
QAST::Op.new(
:op('isrwcont'),
QAST::Var.new( :name($result), :scope('local') )
:op('bind'),
QAST::Var.new( :name($result), :scope('local'), :decl('var') ),
QAST::Op.new( :op('wantdecont'), $qast[0] )
),
# Yes; does it contain an Iterable? If so, rewrap it. If
# not, strip it.
QAST::Op.new(
# If it's a container...
:op('if'),
QAST::Op.new(
:op('istype'),
QAST::Var.new( :name($result), :scope('local') ),
$Iterable
),
QAST::Op.new(
:op('p6bindattrinvres'),
QAST::Op.new( :op('create'), $Scalar ),
$Scalar,
QAST::SVal.new( :value('$!value') ),
:op('if'),
QAST::Op.new(
:op('decont'),
:op('isconcrete_nd'),
QAST::Var.new( :name($result), :scope('local') )
),
QAST::Op.new(
:op('iscont'),
QAST::Var.new( :name($result), :scope('local') )
)
),
# It's a container; is it an rw one?
QAST::Op.new(
:op('decont'),
:op('if'),
QAST::Op.new(
:op('isrwcont'),
QAST::Var.new( :name($result), :scope('local') )
),
# Yes; does it contain an Iterable? If so, rewrap it. If
# not, strip it.
QAST::Op.new(
:op('if'),
QAST::Op.new(
:op('istype'),
QAST::Var.new( :name($result), :scope('local') ),
$Iterable
),
QAST::Op.new(
:op('p6bindattrinvres'),
QAST::Op.new( :op('create'), $Scalar ),
$Scalar,
QAST::SVal.new( :value('$!value') ),
QAST::Op.new(
:op('decont'),
QAST::Var.new( :name($result), :scope('local') )
)
),
QAST::Op.new(
:op('decont'),
QAST::Var.new( :name($result), :scope('local') )
)
),
# Not rw, so leave container in place.
QAST::Var.new( :name($result), :scope('local') )
)
),
# Not rw, so leave container in place.
QAST::Var.new( :name($result), :scope('local') )
),
# Not a container, so just hand back value
QAST::Var.new( :name($result), :scope('local') )
)
)
});
),
# Not a container, so just hand back value
QAST::Var.new( :name($result), :scope('local') )
)
)
}
});
}
{
my $is_moar;
register_op_desugar('p6assign', -> $qast {
Expand Down
77 changes: 77 additions & 0 deletions src/vm/moar/spesh-plugins.nqp
View file
Expand Up @@ -44,6 +44,83 @@ nqp::speshreg('perl6', 'maybemeth', -> $obj, str $name {
!! &discard-and-nil
});

## Return value decontainerization plugin

# Often we have nothing at all to do, in which case we can make it a no-op.
# Other times, we need a decont. In a few, we need to re-wrap it.

{
# We look up Iterable when the plugin is used.
my $Iterable := NQPMu;

sub identity($obj) { $obj }
sub decont($obj) { nqp::decont($obj) }
sub recont($obj) {
my $rc := nqp::create(Scalar);
nqp::bindattr($rc, Scalar, '$!value', nqp::decont($obj));
$rc
}
sub decontrv($cont) {
if nqp::isrwcont($cont) {
# It's an RW container, so we really need to decont it.
my $rv := nqp::decont($cont);
if nqp::istype($rv, $Iterable) {
my $rc := nqp::create(Scalar);
nqp::bindattr($rc, Scalar, '$!value', $rv);
$rc
}
else {
$rv
}
}
else {
# A read-only container, so just return it.
$cont
}
}

nqp::speshreg('perl6', 'decontrv', sub ($rv) {
$Iterable := nqp::gethllsym('perl6', 'Iterable');
nqp::speshguardtype($rv, nqp::what_nd($rv));
if nqp::isconcrete_nd($rv) && nqp::iscont($rv) {
# Guard that it's concrete, so this only applies for container
# instances.
nqp::speshguardconcrete($rv);

# If it's a Scalar container then we can optimize further.
if nqp::eqaddr(nqp::what_nd($rv), Scalar) {
# Grab the descriptor.
my $desc := nqp::speshguardgetattr($rv, Scalar, '$!descriptor');
if nqp::isconcrete($desc) {
# Descriptor, so `rw`. Guard on type of value. If it's
# Iterable, re-containerize. If not, just decont.
nqp::speshguardconcrete($desc);
my $value := nqp::speshguardgetattr($rv, Scalar, '$!value');
nqp::speshguardtype($value, nqp::what_nd($value));
return nqp::istype($value, $Iterable) ?? &recont !! &decont;
}
else {
# No descriptor, so it's already readonly. Identity.
nqp::speshguardtypeobj($desc);
return &identity;
}
}

# Otherwise, full decont.
return &decontrv;
}
else {
# No decontainerization to do, so just produce identity.
unless nqp::isconcrete($rv) {
# Needed as a container's type object is not a container, but a
# concrete instance would be.
nqp::speshguardtypeobj($rv);
}
return &identity;
}
});
}

## Assignment plugin

# We case-analyze assignments and provide these optimized paths for a range of
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