kernel -> ssa: implement if-statements

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 2e107bce7a3590aebbe5283701a917279120c803..f1294a442e966673024e92a4b2e9a6773b53f638 100644
--- a/pkg/compiler/lib/src/ssa/builder_kernel.dart
+++ b/pkg/compiler/lib/src/ssa/builder_kernel.dart
@@ -2,6 +2,7 @@
 // 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/ssa/ssa_branch_builder.dart';
 import 'package:kernel/ast.dart' as ir;
 
 import '../common/codegen.dart' show CodegenRegistry, CodegenWorkItem;
@@ -67,7 +68,6 @@ class KernelSsaBuilder extends ir.Visitor with GraphBuilder {
 
   JavaScriptBackend get backend => compiler.backend;
 
-  LocalsHandler localsHandler;
   SourceInformationBuilder sourceInformationBuilder;
   KernelAstAdapter astAdapter;
 
@@ -113,6 +113,23 @@ class KernelSsaBuilder extends ir.Visitor with GraphBuilder {
     return graph;
   }
 
+  @override
+  HBoolify popBoolified() {
+    HInstruction value = pop();
+    // TODO(het): add boolean conversion type check

[Siggi Cherem (dart-lang), 2016/09/01 23:51:21]

once you do, would this method move to GraphBuilder?

[Harry Terkelsen, 2016/09/02 17:52:27]

Yes, if we also pass in the boolType

+    HInstruction result = new HBoolify(value, backend.boolType);
+    add(result);
+    return result;
+  }
+
+  // TODO(het): This implementation is shared with [SsaBuilder]. Should we just
+  // allow [GraphBuilder] to access `compiler`?

[Siggi Cherem (dart-lang), 2016/09/01 23:51:22]

seems ok, is it only for boolType? We could also just pass that to the builder

[Harry Terkelsen, 2016/09/02 17:52:27]

It's for boolType and for the 'compiler' argument to graph.addConstantNull

+  @override
+  pushCheckNull(HInstruction expression) {
+    push(new HIdentity(
+        expression, graph.addConstantNull(compiler), null, backend.boolType));
+  }
+
   /// Builds a SSA graph for [method].
   void buildMethod(IrFunction method, FunctionElement functionElement) {
     openFunction(method, functionElement);
@@ -172,6 +189,15 @@ class KernelSsaBuilder extends ir.Visitor with GraphBuilder {
   }
 
   @override
+  void visitIfStatement(ir.IfStatement ifStatement) {
+    SsaBranchBuilder branchBuilder = new SsaBranchBuilder(this, compiler);
+    branchBuilder.handleIf(
+        () => ifStatement.condition.accept(this),
+        () => ifStatement.then.accept(this),
+        () => ifStatement.otherwise?.accept(this));
+  }
+
+  @override
   void visitIntLiteral(ir.IntLiteral intLiteral) {
     stack.add(graph.addConstantInt(intLiteral.value, compiler));
   }