Implement experimental exponentiation operator

src/compiler/typer.cc

Index: src/compiler/typer.cc
diff --git a/src/compiler/typer.cc b/src/compiler/typer.cc
index 9af65597bf5527e9d60ca3c67b38300726cfe1bb..2f01e14243e95776467dee26dcae281a99456459 100644
--- a/src/compiler/typer.cc
+++ b/src/compiler/typer.cc
@@ -350,6 +350,7 @@ class Typer::Visitor : public Reducer {
   static Type* JSMultiplyRanger(Type::RangeType*, Type::RangeType*, Typer*);
   static Type* JSDivideRanger(Type::RangeType*, Type::RangeType*, Typer*);
   static Type* JSModulusRanger(Type::RangeType*, Type::RangeType*, Typer*);
+  static Type* JSExponentiateRanger(Type::RangeType*, Type::RangeType*, Typer*);
 
   static ComparisonOutcome JSCompareTyper(Type*, Type*, Typer*);
 
@@ -1223,6 +1224,18 @@ Type* Typer::Visitor::JSModulusTyper(Type* lhs, Type* rhs, Typer* t) {
 }
 
 
+Type* Typer::Visitor::JSExponentiateRanger(Type::RangeType* lhs,
+                                           Type::RangeType* rhs, Typer* t) {
+  return Type::Range(-V8_INFINITY, +V8_INFINITY, t->zone());

[Michael Starzinger, 2015/02/24 14:09:03]

This is a pretty broad range. :)

[caitp (gmail), 2015/02/24 14:56:12]

I have some ideas for how to make it a bit more narrow, but it's still going to
be [-ε...-1], [ε...1], [-ε...-Infinity], [ε...Infinity] --- broad range seemed
easiest to get working quickly.

+}
+
+
+Type* Typer::Visitor::JSExponentiateTyper(Type* lhs, Type* rhs, Typer* t) {
+  if (lhs->Is(Type::NaN()) || rhs->Is(Type::NaN())) return Type::NaN();

[Michael Starzinger, 2015/02/24 14:09:03]

Isn't the exponentiation supposed to perform an implicit ToNumber conversion (or
something similar)? This doesn't seem to be reflected here.

[caitp (gmail), 2015/02/24 14:56:12]

I might be misunderstanding what the typer is doing. I think I'm determining a
type for the node output, based on the input nodes? Is there a way to tell the
input nodes they need to be converted to numbers here?

+  return Type::Number();
+}
+
+
 // JS unary operators.
 
 
@@ -1576,6 +1589,11 @@ Bounds Typer::Visitor::TypeNumberModulus(Node* node) {
 }
 
 
+Bounds Typer::Visitor::TypeNumberExponentiate(Node* node) {
+  return Bounds(Type::None(zone()), Type::Number(zone()));
+}
+
+
 Bounds Typer::Visitor::TypeNumberToInt32(Node* node) {
   return TypeUnaryOp(node, NumberToInt32);
 }