Add deferred loading to Kernel.

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 974f5616b6b3d1fc00013fa34400c5585e43d9cb..330dcbac373cd9501672ecf08110cbf920ee2689 100644
--- a/pkg/compiler/lib/src/ssa/builder_kernel.dart
+++ b/pkg/compiler/lib/src/ssa/builder_kernel.dart
@@ -593,6 +593,36 @@ class KernelSsaBuilder extends ir.Visitor with GraphBuilder {
   }
 
   @override
+  void visitCheckLibraryIsLoaded(ir.CheckLibraryIsLoaded checkLoad) {
+    HInstruction prefixConstant = graph.addConstantString(
+        new DartString.literal(checkLoad.import.name), closedWorld);
+    // TODO(efortuna): Optimization opportunity! Make this constant file name
+    // some sort of global constant (or a constant in the check loaded function)
+    // to look up rather than always passing in. Also note that the URI passed
+    // here is longer that in the original one, which called
+    // compiler.deferredLoadTask.getImportDeferName and then also needed the
+    // previsit function to hold the prefix element.

[sra1, 2017/02/14 03:14:06]

How are we going to fix this (getting the shorter name)?
The deferredLoadTask is still needed to track the chunks.
Can we call it here, or add a new entry point?

[Emily Fortuna, 2017/02/14 20:56:28]

This is what I was talking about last week. We can do so, but it requires a
previsit function to store the prefix element until we reach this function. We
can also write a variant of the "make unique" URI function that we're doing in
the original version, but it seems like it ties us closer to the element model
with very little benefit for a lot of extra work.

[sra1, 2017/02/14 21:55:27]

I'm concerned that two builds will generate different code because of generated
libraries being in some different tmp directory each build.
Or if you build and I build, we get our home directory aka user names in the
generated code.

State in the TODO that we want a shorter name that is independent of the
directory in which the source tree lives.

[Emily Fortuna, 2017/02/15 01:02:31]

Fixed it properly.

+    HInstruction uriConstant = graph.addConstantString(
+        new DartString.literal(checkLoad.import.importedLibrary.importUri),
+        closedWorld);
+    _pushStaticInvocation(astAdapter.checkDeferredIsLoaded,
+        [prefixConstant, uriConstant], astAdapter.checkDeferredIsLoadedType);
+  }
+
+  @override
+  void visitLoadLibrary(ir.LoadLibrary loadLibrary) {
+    // TODO(efortuna): Source information!
+    push(new HInvokeStatic(
+        backend.helpers.loadLibraryWrapper,
+        [
+          graph.addConstantString(
+              new DartString.literal(loadLibrary.import.name), closedWorld)
+        ],
+        commonMasks.nonNullType,
+        targetCanThrow: false));
+  }
+
+  @override
   void visitBlock(ir.Block block) {
     assert(!isAborted());
     for (ir.Statement statement in block.statements) {
@@ -1830,8 +1860,9 @@ class KernelSsaBuilder extends ir.Visitor with GraphBuilder {
       // Invoke the getter
       _pushStaticInvocation(staticTarget, const <HInstruction>[],
           astAdapter.returnTypeOf(staticTarget));
-    } else if (staticTarget is ir.Field && staticTarget.isConst) {
-      assert(staticTarget.initializer != null);
+    } else if (staticTarget is ir.Field &&
+        (staticTarget.isConst ||
+            staticTarget.isFinal && !_isLazyStatic(staticTarget))) {
       stack.add(graph.addConstant(
           astAdapter.getConstantFor(staticTarget.initializer), closedWorld));
     } else {