Question on C1's as_ValueType(ciConstant value)

[Krystal Mok]

Oops, s/GraphKit/GraphBuilder/ in my last email.

Thanks,
Kris

On Sun, Jun 7, 2015 at 10:47 PM, Krystal Mok <rednaxelafx at gmail.com> wrote:

> Hi compiler team,
>
> I'd like to ask a question about a piece of code in C1. The code snippet
> below is from the tip version of jdk9/hs-comp.
>
> 145 ValueType* as_ValueType(ciConstant value) {
> 146   switch (value.basic_type()) {
> 147     case T_BYTE   : // fall through
> 148     case T_CHAR   : // fall through
> 149     case T_SHORT  : // fall through
> 150     case T_BOOLEAN: // fall through
> 151     case T_INT    : return new IntConstant   (value.as_int   ());
> 152     case T_LONG   : return new LongConstant  (value.as_long  ());
> 153     case T_FLOAT  : return new FloatConstant (value.as_float ());
> 154     case T_DOUBLE : return new DoubleConstant(value.as_double());
> 155     case T_ARRAY  : // fall through (ciConstant doesn't have an array
> accessor)
> 156     case T_OBJECT : return new ObjectConstant(value.as_object());
> 157   }
> 158   ShouldNotReachHere();
> 159   return illegalType;
> 160 }
>
> On lines 155 and 156, both basic types T_ARRAY and T_OBJECT turns into a
> ObjectConstant.
> That's not consistent with the handling in GraphKit::load_constant(),
> where ArrayConstant, InstanceConstant and ObjectConstant are treated
> separately.
>
> I ran into this inconsistency when I wanted to try out something with
> array constants. But I was only able to reach the constant from an
> ObjectConstant, instead of an ArrayConstant like I was expecting.
>
> If people agree that this inconsistency should be fixed, I'd be happy to
> provide a patch and test it.
>
> Thanks,
> Kris
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/attachments/20150607/ab0f6fff/attachment-0001.html>