RFC: Start refactoring to provide more than a single backend.

lib/compiler/implementation/ssa/builder.dart

Index: lib/compiler/implementation/ssa/builder.dart
diff --git a/lib/compiler/implementation/ssa/builder.dart b/lib/compiler/implementation/ssa/builder.dart
index e867f6c16aa00e90ce73d9ab1ddfe1c83ec018f1..85495a5cbdf9de508b242242a786b03c319657fe 100644
--- a/lib/compiler/implementation/ssa/builder.dart
+++ b/lib/compiler/implementation/ssa/builder.dart
@@ -781,7 +781,7 @@ class SsaBuilder implements Visitor {
   SsaBuilder(Compiler compiler, WorkItem work)
     : this.compiler = compiler,
       this.work = work,
-      interceptors = compiler.builder.interceptors,
+      interceptors = compiler.backend.builder.interceptors,

[ahe, 2012/05/11 11:39:48]

I think this will cause a type warning. compiler.backend is a Backend which
doesn't have a builder.

[Anton Muhin, 2012/05/12 15:48:43]

I am sorry I probably missed something, what kind of warning it will cause? 
While being run, it shouldn't be an issue (I hope) as backend will have
necessary methods.  What I am missing? 

[ngeoffray, 2012/05/13 17:02:47]

It will create a static type warning, eg: "interface backend has no field named
'builder'". We want to be warning free. Indeed, at runtime, the backend object
will have a 'builder' field, but Peter is referring to compile-time.

[Anton Muhin, 2012/05/14 14:36:45]

Thanks a lot for explanation, Nicolas!

Q: how do I test my changes?  Currently I use:


./tools/build.py --mode=release create_sdk && ./tools/test.py --mode=release
--compiler=dart2js --runtime=d8 --time --use-sdk --report --shards=4 --shard=1

but that didn't show any warning.

I remember you used to have a presubmit script.

Any advice?

And to solve the problem I try to pass proper instances, e.g. JavaScriptBackend,
etc.
On 2012/05/13 17:02:47, ngeoffray wrote:

[ahe, 2012/05/14 15:56:41]

If you want to make sure you run all the tests, you should remove the "shard"
related options. If you just want to run a quarter of the tests, then the shard
options are fine. When making changes to the infrastructure (like you are)
running only a subset of tests is probably sufficient.

Also, if you remove --use-sdk, you don't have to run build.py.

You should also make sure that the unit tests still run. These are likely to
break when refactoring:

./tools/test.py -mrelease -rvm leg

The unit tests must be run on the VM because dart2js is not self-hosted, and
because they are *unit* tests, not *integration* tests. Side note: we should
probably start looking into getting the unit tests running on dart2js as well,
but I don't think that can replace running them on the VM.

       methodInterceptionEnabled = true,
       elements = work.resolutionTree,
       graph = new HGraph(),
@@ -1465,7 +1465,7 @@ class SsaBuilder implements Visitor {
   }
 
   visitFunctionExpression(FunctionExpression node) {
-    ClosureData nestedClosureData = compiler.builder.closureDataCache[node];
+    ClosureData nestedClosureData = compiler.backend.builder.closureDataCache[node];
     if (nestedClosureData === null) {
       // TODO(floitsch): we can only assume that the reason for not having a
       // closure data here is, because the function is inside an initializer.