Add Vector type to Kernel

pkg/kernel/lib/ast.dart

Index: pkg/kernel/lib/ast.dart
diff --git a/pkg/kernel/lib/ast.dart b/pkg/kernel/lib/ast.dart
index 9d6d5cdd073424bf9d2999e6e6673af3d96dd8bc..ddab8f0ea57808489aebd6eb5d2cb22a6f03b601 100644
--- a/pkg/kernel/lib/ast.dart
+++ b/pkg/kernel/lib/ast.dart
@@ -2750,6 +2750,116 @@ class CheckLibraryIsLoaded extends Expression {
   transformChildren(Transformer v) {}
 }
 
+/// Expression of the form `MakeVector(N)` where `N` is an integer literal.

[asgerf, 2017/03/23 11:53:50]

`N` is no longer an integer literal. It would be more useful to say e.g. "where
`N` is the length of the vector".

The form `MakeVector(N)` doesn't really mean much. I used that style to document
some AST nodes that have an obvious correspondence to a Dart syntactic form, but
this is not the case here.

I would like to see some documentation to explain what a "vector" is and what
they are used for, and this seems like a good place to do it (or perhaps on
VectorType).

A couple of points worth mentioning:
- Vectors are fixed-length
- Not user-visible objects
- Access to vectors is untyped and without bounds checks
- Vectors are introduced by closure conversion

[Kevin Millikin (Google), 2017/03/23 12:01:03]

'integer literal' ==> 'integer'.

[Dmitry Stefantsov, 2017/03/27 10:57:08]

Done.

[Dmitry Stefantsov, 2017/03/27 10:57:08]

Yes. It makes sense. I put the detailed comment next to VectorType.

+class VectorCreation extends Expression {
+  int length;
+
+  VectorCreation(this.length);
+
+  accept(ExpressionVisitor v) => v.visitVectorCreation(this);
+  accept1(ExpressionVisitor1 v, arg) => v.visitVectorCreation(this, arg);
+
+  visitChildren(Visitor v) {}
+
+  transformChildren(Transformer v) {}
+
+  DartType getStaticType(TypeEnvironment types) {
+    return const VectorType();
+  }
+}
+
+/// Expression of the form `v[i]` where `v` is a vector expression, and `i` is
+/// an integer literal used as an index.

[Kevin Millikin (Google), 2017/03/23 12:01:03]

'integer literal' ==> 'integer'.

[Dmitry Stefantsov, 2017/03/27 10:57:08]

Done.

+class VectorGet extends Expression {
+  Expression vectorExpression;
+  int index;
+
+  VectorGet(this.vectorExpression, this.index) {
+    vectorExpression?.parent = this;
+  }
+
+  accept(ExpressionVisitor v) => v.visitVectorGet(this);
+  accept1(ExpressionVisitor1 v, arg) => v.visitVectorGet(this, arg);
+
+  visitChildren(Visitor v) {
+    vectorExpression.accept(v);
+  }
+
+  transformChildren(Transformer v) {
+    if (vectorExpression != null) {
+      vectorExpression = vectorExpression.accept(v);
+      vectorExpression?.parent = this;
+    }
+  }
+
+  DartType getStaticType(TypeEnvironment types) {
+    return const DynamicType();
+  }
+}
+
+/// Expressoins of the form `v[i] = x` where `v` is a vector expression, `i` is

[asgerf, 2017/03/23 11:53:50]

Expressoins -> Expression

[Kevin Millikin (Google), 2017/03/23 12:01:03]

'Expressoins' ==> 'Expressions'.
'integer literal' ==> 'integer'.

[Dmitry Stefantsov, 2017/03/27 10:57:08]

Done.

[Dmitry Stefantsov, 2017/03/27 10:57:08]

Done.

+/// an integer literal used as an index, and `x` is an arbitrary expression.
+class VectorSet extends Expression {
+  Expression vectorExpression;
+  int index;
+  Expression value;
+
+  VectorSet(this.vectorExpression, this.index, this.value) {
+    vectorExpression?.parent = this;
+    value?.parent = this;
+  }
+
+  accept(ExpressionVisitor v) => v.visitVectorSet(this);
+  accept1(ExpressionVisitor1 v, arg) => v.visitVectorSet(this, arg);
+
+  visitChildren(Visitor v) {
+    vectorExpression.accept(v);
+    value.accept(v);
+  }
+
+  transformChildren(Transformer v) {
+    if (vectorExpression != null) {
+      vectorExpression = vectorExpression.accept(v);
+      vectorExpression?.parent = this;
+    }
+    if (value != null) {
+      value = value.accept(v);
+      value?.parent = this;
+    }
+  }
+
+  DartType getStaticType(TypeEnvironment types) {
+    return value.getStaticType(types);
+  }
+}
+
+/// Expression of the form `CopyVector(v)` where `v` is a vector expressoin.

[asgerf, 2017/03/23 11:53:50]

expressoin -> expression

[Kevin Millikin (Google), 2017/03/23 12:01:03]

'expressoin' ==> 'expression'.

[Dmitry Stefantsov, 2017/03/27 10:57:08]

Done.

[Dmitry Stefantsov, 2017/03/27 10:57:08]

Done.

+class VectorCopy extends Expression {
+  Expression vectorExpression;
+
+  VectorCopy(this.vectorExpression) {
+    vectorExpression?.parent = this;
+  }
+
+  accept(ExpressionVisitor v) => v.visitVectorCopy(this);
+  accept1(ExpressionVisitor1 v, arg) => v.visitVectorCopy(this, arg);
+
+  visitChildren(Visitor v) {
+    vectorExpression.accept(v);
+  }
+
+  transformChildren(Transformer v) {
+    if (vectorExpression != null) {
+      vectorExpression = vectorExpression.accept(v);
+      vectorExpression?.parent = this;
+    }
+  }
+
+  DartType getStaticType(TypeEnvironment types) {
+    return const VectorType();
+  }
+}
+
 // ------------------------------------------------------------------------
 //                              STATEMENTS
 // ------------------------------------------------------------------------
@@ -3652,6 +3762,13 @@ class InterfaceType extends DartType {
   }
 }
 
+class VectorType extends DartType {

[asgerf, 2017/03/23 11:53:50]

Please check all existing DartTypeVisitors and override visitVectorType if
necessary.  I know _TypeSubstitutor in type_algebra.dart needs it.

[Dmitry Stefantsov, 2017/03/27 10:57:08]

Thanks! Done.

+  const VectorType();
+
+  accept(DartTypeVisitor v) => v.visitVectorType(this);
+  visitChildren(Visitor v) {}
+}
+
 /// A possibly generic function type.
 class FunctionType extends DartType {
   final List<TypeParameter> typeParameters;