dart2js cps: Generate interceptors at use-site and share afterwards.

tests/compiler/dart2js_extra/dart2js_extra.status

 # Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 # 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.
 
 [ $compiler == dart2js ]
 16407_test: Fail # Issue 16407
 class_test: Fail
 statements_test: Fail
 typed_locals_test: Fail
 no_such_method_test: Fail # Wrong Invocation.memberName.
@@ skipping 52 matching lines @@
 [ $host_checked && $compiler == dart2js && $cps_ir ]
 21724_test: Crash # Please triage this failure.
 
 [ $compiler == none && $runtime == vm ]
 invalid_annotation_test/01: MissingCompileTimeError, OK # vm is lazy
 
 [ $compiler == dart2js && $cps_ir ]
 16407_test: Pass # Please triage this failure.
 22868_test: RuntimeError # Issue 23997
 22895_test: RuntimeError # Issue 23997
+23432_test: RuntimeError # Issue 23432

[asgerf, 2015/08/25 14:00:42]

It sort of passed for the wrong reason, and also seems to pass for the wrong
reason in the SSA backend.

[sra1, 2015/08/31 18:12:07]

What is the wrong reason?

[asgerf, 2015/08/31 18:23:05]

Ah, right. I was trying to get to the bottom of things, but then got
side-tracked.

There is a call to getInterceptor that gets a numeric argument, but JSNumber is
not an intercepted class because numbers don't respond to that selector. The
call intentionally fails at runtime.

In CPS, the getInterceptor call returns the number itself, and the resulting
exception message is not rewritten into a nice exception message. It says
something like "getInterceptor(x).blah" is not a method where it was supposed to
say something like "12345 does not have a method blah".

In SSA, the getInterceptor call has a case for UnknownJavaScriptObject which is
only there because the program contains a try/catch. The number is (on purpose?)
classified as such an unknown object. The unknown object's method table then
responds to the message by throwing a nice-looking exception message and passes
the test.

The UnknownJavaScriptObject case seems to go away if there is no try/catch.

I can make SSA generate just as bad error messages by removing all try/catches
from the program, but we can't make a test case for it because it needs a
try/catch to inspect the error message.

I don't know the official strategy for getting nice-looking exception message.
Having the UnknownJavaScriptObject case isn't such a bad idea for handling
negative cases, but the condition under which that happens in the SSA is weird.

 async_stacktrace_test/asyncStar: Crash # (foo()async*{try {tr...  cannot handle sync*/async* functions
 async_stacktrace_test/none: RuntimeError # $async$temp1.Tracer$ is not a function
 closure_capture5_test: Crash # (i=0): For-loop variable captured in loop header
 deferred/deferred_class_test: RuntimeError # Z.loadLibrary is not a function
 deferred/deferred_constant2_test: Crash # (lib.C1): deferred access is not implemented
 deferred/deferred_constant3_test: Crash # (lib.C1): deferred access is not implemented
 deferred/deferred_constant4_test: RuntimeError # B.loadLibrary is not a function
 deferred/deferred_function_test: Crash # (lib.foo): deferred access is not implemented
 deferred/deferred_mirrors1_test: Crash # (lazy.foo()): deferred access is not implemented
 deferred/deferred_overlapping_test: RuntimeError # E.loadLibrary is not a function
 deferred_fail_and_retry_test: Crash # (lib.foo()): deferred access is not implemented
 deferred_fail_and_retry_worker_test: Crash # (lib.foo()): deferred access is not implemented
 deferred_split_test: Crash # (b.createA()): deferred access is not implemented
 mirror_printer_test: Crash # (static Iterable<Str...  cannot handle sync*/async* functions
 mirror_test: Crash # (static Iterable<Str...  cannot handle sync*/async* functions
 reflect_native_types_test: Crash # (static Iterable<Str...  cannot handle sync*/async* functions
 switch_test/none: Crash # (switch (val){foo:ba...  continue to a labeled switch case