Make conflicting summary check configurable

Make conflicting summary check configurable

Not sure this is a great idea.  DDC will go awry if multiple copies of
the same type exist.  Can analysis or any other analyzer-based tool?

R=brianwilkerson@google.com, paulberry@google.com

Committed: https://github.com/dart-lang/sdk/commit/1112ad24cc157b492e8d10e9bce34b7124cb01c3

[vsm, 2017-04-18 22:14:04]

Description was changed from

==========
Make conflicting summary check configurable

Not sure this is a great idea.  DDC will go awry if multiple copies of
the same type exist.  Can analysis or any other analyzer-based tool?
==========

to

==========
Make conflicting summary check configurable

Not sure this is a great idea.  DDC will go awry if multiple copies of
the same type exist.  Can analysis or any other analyzer-based tool?
==========

[vsm, 2017-04-18 22:14:04]

vsm@google.com changed reviewers:
+ brianwilkerson@google.com, paulberry@google.com

[Brian Wilkerson, 2017-04-18 22:23:50]

lgtm.

Do you expect this to be a short-term solution to allowing different behavior in
different contexts, or is this a permanent fix?

> DDC will go awry if multiple copies of the same type exist. Can analysis or
any other analyzer-based tool?

I don't really have the background for this change in my brain, so I'm not sure
what you mean by "multiple copies of the same type". If you mean "multiple
instances of ClassElement that compare equal but are not identical", then yes,
the analyzer might well have problems with that.

Is there an issue open that I can look at for more background?

[vsm, 2017-04-18 22:37:18]

On 2017/04/18 22:23:50, Brian Wilkerson wrote:
> lgtm.
> 
> Do you expect this to be a short-term solution to allowing different behavior
in
> different contexts, or is this a permanent fix?
> 
> > DDC will go awry if multiple copies of the same type exist. Can analysis or
> any other analyzer-based tool?
> 
> I don't really have the background for this change in my brain, so I'm not
sure
> what you mean by "multiple copies of the same type". If you mean "multiple
> instances of ClassElement that compare equal but are not identical", then yes,
> the analyzer might well have problems with that.
> 
> Is there an issue open that I can look at for more background?

This is an internal link:

b/37267486

For DDC, summaries match the unit of code generation.  If the same input appears
in multiple summaries, we've generated multiple copies of the corresponding
output - i.e., multiple copies of the same type, same top-level vars.  This
leads to subtle runtime errors.

It's analogous to the link time error you'd get with gcc if the same source
appears in multiple .o files.

[Paul Berry, 2017-04-19 07:54:13]

lgtm.  AFAIK analyzer doesn't have any problems if a file is included in
multiple summaries.

[vsm, 2017-04-20 16:20:17]

Description was changed from

==========
Make conflicting summary check configurable

Not sure this is a great idea.  DDC will go awry if multiple copies of
the same type exist.  Can analysis or any other analyzer-based tool?
==========

to

==========
Make conflicting summary check configurable

Not sure this is a great idea.  DDC will go awry if multiple copies of
the same type exist.  Can analysis or any other analyzer-based tool?

R=brianwilkerson@google.com, paulberry@google.com

Committed:
https://github.com/dart-lang/sdk/commit/1112ad24cc157b492e8d10e9bce34b7124cb01c3
==========

[vsm, 2017-04-20 16:20:18]

Committed patchset #1 (id:1) manually as
1112ad24cc157b492e8d10e9bce34b7124cb01c3 (presubmit successful).