Report NullPointerException when we try to construct a regular expression

Report NullPointerException when we try to construct a regular expression
using a NULL pointer.
Report NullPointerException instead of ObjectNotClosureException when the
closure object is Null.
Committed: https://code.google.com/p/dart/source/detail?r=901

[regis, 2011-10-26 23:55:17]

LGTM

[turnidge, 2011-10-27 17:08:19]

LGTM.

One comment below, but it is more for discussion than suggesting that you change
this CL.

http://codereview.chromium.org/8363034/diff/1/lib/regexp.cc
File lib/regexp.cc (right):

http://codereview.chromium.org/8363034/diff/1/lib/regexp.cc#newcode86
lib/regexp.cc:86: CheckAndThrowExceptionIfNull(str);
I just wanted to point out that by putting the check in the C++ code instead of
the dart code, we will miss out on the chance to eliminate the null check in
cases where the compiler knows that str is non-null -- for example, if it has
just been allocated.  Not sure how much this matters though.

[siva, 2011-10-28 06:14:43]

http://codereview.chromium.org/8363034/diff/1/lib/regexp.cc
File lib/regexp.cc (right):

http://codereview.chromium.org/8363034/diff/1/lib/regexp.cc#newcode86
lib/regexp.cc:86: CheckAndThrowExceptionIfNull(str);
Doing null pointer checks and throwing NullPointerException in dart code seems
weird as it is supposed to happen through a call to noSuchMethod.
I am trying to see if it would be possible to access str in dart code and
trigger a call to noSuchMethod, probably for another CL.

On 2011/10/27 17:08:19, turnidge wrote:
> I just wanted to point out that by putting the check in the C++ code instead
of
> the dart code, we will miss out on the chance to eliminate the null check in
> cases where the compiler knows that str is non-null -- for example, if it has
> just been allocated.  Not sure how much this matters though.