Is RegisterMap updated?

[Andrew Haley]

On 1/29/19 11:24 AM, David Griffiths wrote:
> Hi, in CompiledVFrame.createStackValue there is the following code:
> 
>       // First find address of value
>       Address valueAddr = loc.isRegister()
>         // Value was in a callee-save register
>         ? getRegisterMap().getLocation(new VMReg(loc.getRegisterNumber()))
>         // Else value was directly saved on the stack. The frame's
> original stack pointer,
>         // before any extension by its callee (due to Compiler1
> linkage on SPARC), must be used.
>         : ((Address)fr.getUnextendedSP()).addOffsetTo(loc.getStackOffset());
> 
> It appears from what I can make out that for the register case the map
> is not updated and so valueAddr is null. The only thing I can see that
> calls setLocation is updateMapWithSavedLink. Seems like it should be
> possible to return the register value for the frame at the top of the
> stack though?

It could be, but we don't do that. The registers in the map are those
pushed onto the stack by generated Java code.

-- 
Andrew Haley
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
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