Throw Error on unreachable code rather than a String.

Throw Error on unreachable code rather than throwing a String.

Still under a 'flag'.
Enable with:

  DART_VM_OPTIONS=-Dunreachable-throw=true  <compile>


These tests fail with an [empty] input to createRuntimeType.

DART_VM_OPTIONS=-Dunreachable-throw=true  tools/test.py -mrelease -cdart2js -rd8 dart2js_extra/deferred/deferred_mirrors1_test
DART_VM_OPTIONS=-Dunreachable-throw=true  tools/test.py -mrelease -cdart2js -rd8 dart2js_extra/mirrors_used_warning2_test
R=sigmund@google.com

Committed: https://github.com/dart-lang/sdk/commit/d0c00d2b61a2a8a32c87ac24d333e21ace87df20

[sra1, 2015-09-18 21:45:00]

sra@google.com changed reviewers:
+ sigmund@google.com

[sra1, 2015-09-18 21:50:10]

Patchset #1 (id:1) has been deleted

[Siggi Cherem (dart-lang), 2015-09-18 22:19:56]

lgtm

https://chromiumcodereview.appspot.com/1355873003/diff/20001/pkg/compiler/lib...
File pkg/compiler/lib/src/ssa/builder.dart (right):

https://chromiumcodereview.appspot.com/1355873003/diff/20001/pkg/compiler/lib...
pkg/compiler/lib/src/ssa/builder.dart:1647: /// Use sparingly. In order for the
comment to be retained is is modeled as
is is => it is

https://chromiumcodereview.appspot.com/1355873003/diff/20001/pkg/compiler/lib...
pkg/compiler/lib/src/ssa/builder.dart:1648: /// having side effects which will
inhibit code motion.
yikes! what if we attach comments to existing nodes? e.g. above we would attach
it to the invoke-static node?

[sra1, 2015-09-18 22:34:30]

https://chromiumcodereview.appspot.com/1355873003/diff/20001/pkg/compiler/lib...
File pkg/compiler/lib/src/ssa/builder.dart (right):

https://chromiumcodereview.appspot.com/1355873003/diff/20001/pkg/compiler/lib...
pkg/compiler/lib/src/ssa/builder.dart:1647: /// Use sparingly. In order for the
comment to be retained is is modeled as
On 2015/09/18 22:19:55, Siggi Cherem (dart-lang) wrote:
> is is => it is

Done.

https://chromiumcodereview.appspot.com/1355873003/diff/20001/pkg/compiler/lib...
pkg/compiler/lib/src/ssa/builder.dart:1648: /// having side effects which will
inhibit code motion.
On 2015/09/18 22:19:55, Siggi Cherem (dart-lang) wrote:
> yikes! what if we attach comments to existing nodes? e.g. above we would
attach
> it to the invoke-static node?

That would be better, but what about the case where there is no other node, or
you want a comment regardless of what optimizations might happen?

I could also just remove the comment, and if you need to understand why it is
here, look in the dump-info.

[sra1, 2015-09-18 23:26:00]

Patchset #2 (id:40001) has been deleted

[sra1, 2015-09-18 23:55:04]

Committed patchset #2 (id:60001) manually as
d0c00d2b61a2a8a32c87ac24d333e21ace87df20 (presubmit successful).