• deadalnix (9/9) Dec 04 2015 Hi all,
• Jakob Bornecrantz (4/13) Dec 13 2015 Very intreresting, once support has been added to the druntime
• David Nadlinger via digitalmars-d-ldc (6/13) Dec 13 2015 It's certainly an interesting approach. I supposed we would need to look...

deadalnix <deadalnix gmail.com> writes:

Hi all,

I was at the LLVM meetup yesterday and talked with a contributor 
that use LLVM to run java code. One on the very interesting that 
came up is a way to use segfault in order to do null cheks. It is 
explained here:

http://llvm.org/docs/FaultMaps.html#make-implicit-metadata

I know that ldc generate null checks when calling various 
functions. It may be a good idea, considering this is unexpected, 
ot use the same mechanism in LDC.

Jakob Bornecrantz <wallbraker gmail.com> writes:

On Friday, 4 December 2015 at 23:33:01 UTC, deadalnix wrote:
 Hi all,

 I was at the LLVM meetup yesterday and talked with a 
 contributor that use LLVM to run java code. One on the very 
 interesting that came up is a way to use segfault in order to 
 do null cheks. It is explained here:

 http://llvm.org/docs/FaultMaps.html#make-implicit-metadata

 I know that ldc generate null checks when calling various 
 functions. It may be a good idea, considering this is 
 unexpected, ot use the same mechanism in LDC.

Very intreresting, once support has been added to the druntime
other backends should be able to do the same optimization.

Cheers, Jakob.

David Nadlinger via digitalmars-d-ldc <digitalmars-d-ldc puremagic.com> writes:

On 5 Dec 2015, at 0:33, deadalnix via digitalmars-d-ldc wrote:
 I was at the LLVM meetup yesterday and talked with a contributor that 
 use LLVM to run java code. One on the very interesting that came up is 
 a way to use segfault in order to do null cheks. It is explained here:

 http://llvm.org/docs/FaultMaps.html#make-implicit-metadata

 I know that ldc generate null checks when calling various functions. 
 It may be a good idea, considering this is unexpected, ot use the same 
 mechanism in LDC.

It's certainly an interesting approach. I supposed we would need to look 
into which checks actually make it to the hot patch of optimized builds, 
though, as the comparatively small performance gain probably wouldn't be 
worth it in debug builds.

  — David