implement kernel -> ssa for literals

pkg/compiler/lib/src/ssa/builder_kernel.dart

Index: pkg/compiler/lib/src/ssa/builder_kernel.dart
diff --git a/pkg/compiler/lib/src/ssa/builder_kernel.dart b/pkg/compiler/lib/src/ssa/builder_kernel.dart
index dc58408e7dae17b779b2c74a876d2f29f6ea61f9..15ba1b1c20d463e9d1b852d05a1b39a943cd71a0 100644
--- a/pkg/compiler/lib/src/ssa/builder_kernel.dart
+++ b/pkg/compiler/lib/src/ssa/builder_kernel.dart
@@ -2,9 +2,11 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+import 'package:compiler/src/constants/values.dart';
+import 'package:compiler/src/diagnostics/invariant.dart';
 import 'package:kernel/ast.dart' as ir;
 
-import '../common/codegen.dart' show CodegenWorkItem;
+import '../common/codegen.dart' show CodegenRegistry, CodegenWorkItem;
 import '../common/tasks.dart' show CompilerTask;
 import '../compiler.dart';
 import '../diagnostics/spannable.dart';
@@ -14,6 +16,7 @@ import '../js_backend/backend.dart' show JavaScriptBackend;
 import '../kernel/kernel.dart';
 import '../kernel/kernel_visitor.dart';
 import '../resolution/tree_elements.dart';
+import '../tree/tree.dart' as ast;
 import 'graph_builder.dart';
 import 'locals_handler.dart';
 import 'nodes.dart';
@@ -45,8 +48,10 @@ class SsaKernelBuilderTask extends CompilerTask {
           element,
           work.resolvedAst,
           backend.compiler,
+          work.registry,
           sourceInformationFactory,
-          visitor.nodeToElement);
+          visitor.nodeToElement,
+          visitor.nodeToAst);
       return builder.build();
     });
   }
@@ -57,7 +62,9 @@ class KernelSsaBuilder extends ir.Visitor with GraphBuilder {
   final FunctionElement functionElement;
   final ResolvedAst resolvedAst;
   final Compiler compiler;
+  final CodegenRegistry registry;
   final Map<ir.Node, Element> nodeToElement;
+  final Map<ir.Node, ast.Node> nodeToAst;
 
   JavaScriptBackend get backend => compiler.backend;
 
@@ -69,8 +76,10 @@ class KernelSsaBuilder extends ir.Visitor with GraphBuilder {
       this.functionElement,
       this.resolvedAst,
       this.compiler,
+      this.registry,
       SourceInformationStrategy sourceInformationFactory,
-      this.nodeToElement) {
+      this.nodeToElement,
+      this.nodeToAst) {
     graph.element = functionElement;
     // TODO(het): Should sourceInformationBuilder be in GraphBuilder?
     this.sourceInformationBuilder =
@@ -118,6 +127,14 @@ class KernelSsaBuilder extends ir.Visitor with GraphBuilder {
     graph.finalize();
   }
 
+  ConstantValue getConstantForNode(ast.Node node) {

[Siggi Cherem (dart-lang), 2016/08/26 18:15:57]

Let's create a library and a class with the ir->ast abstractions, so the code
here would contain no import to tree.dart.

For example:
class Kernel2AstAdapter {
  constantValueForSymbol(ir.SymbolLiteral node); // internally accesses node +
resolvedAst to get the right data.
}

[Harry Terkelsen, 2016/08/26 19:52:57]

Done.

+    ConstantValue constantValue =
+        backend.constants.getConstantValueForNode(node, resolvedAst.elements);
+    assert(invariant(node, constantValue != null,
+        message: 'No constant computed for $node'));
+    return constantValue;
+  }
+
   @override
   void visitBlock(ir.Block block) {
     assert(!isAborted());
@@ -159,4 +176,32 @@ class KernelSsaBuilder extends ir.Visitor with GraphBuilder {
   void visitIntLiteral(ir.IntLiteral intLiteral) {
     stack.add(graph.addConstantInt(intLiteral.value, compiler));
   }
+
+  @override
+  visitDoubleLiteral(ir.DoubleLiteral doubleLiteral) {
+    stack.add(graph.addConstantDouble(doubleLiteral.value, compiler));
+  }
+
+  @override
+  visitBoolLiteral(ir.BoolLiteral boolLiteral) {
+    stack.add(graph.addConstantBool(boolLiteral.value, compiler));
+  }
+
+  @override
+  visitStringLiteral(ir.StringLiteral stringLiteral) {
+    stack.add(graph.addConstantString(
+        new ast.DartString.literal(stringLiteral.value), compiler));

[Siggi Cherem (dart-lang), 2016/08/26 18:15:57]

for now because DartString is pretty independent of the rest of the ast, it's
less of an issue IMO to have that dependency, but we can in the future create
the constant directly from the string value (e.g. using `new
StringConstantValue.fromString`).

For now, if we move the rest to the Kernel2ASTAdapter, let's update the import
above to import `tree/dart_string.dart` instead of `tree.dart`.

[Harry Terkelsen, 2016/08/26 19:52:58]

Done.

+  }
+
+  @override
+  visitSymbolLiteral(ir.SymbolLiteral symbolLiteral) {
+    stack.add(graph.addConstant(
+        getConstantForNode(nodeToAst[symbolLiteral]), compiler));
+    registry?.registerConstSymbol(symbolLiteral.value);
+  }
+
+  @override
+  visitNullLiteral(ir.NullLiteral nullLiteral) {
+    stack.add(graph.addConstantNull(compiler));
+  }
 }