On Fri, Dec 13, 2013 at 06:24:21AM -0800, Nicolas B. Pierron wrote: > On 12/13/2013 05:58 AM, Feng, Haitao wrote: > >Yes, I am asking about the spill size for Float32, as they might be in a > >snapshot, I asked about the reading and writing such a stack slot as > >well. It should be 4-byte and the current implement used 8-byte. > > What is 4-byte and is currently 8-byte? The stack slot for the > float, on x64? Is it also the case on x86? For x64, I think the > reason is just because we handle stack slots of 64bits no less. It seems that it is 8-bytes on both x64 and x86 from the source codes:
542 case MIRType_Double: 543 case MIRType_Float32: 544 return LDefinition::DOUBLE; at http://mxr.mozilla.org/mozilla-central/source/js/src/jit/LIR.h#542 By the way, Dan is introducint LDefinition::FLOAT32 at the https://bugzilla.mozilla.org/show_bug.cgi?id=949668. My posted question is solved once his patches are committed. > > The problem might be in the stack allocator, if it does not > interpret floating point values. > > >Could you talk a little bit more on the trouble with Float32x4 and where > >we eagerly spill Value-size content in the code? > > In the bailout code, we are spilling to construct a machine state, > and in the spills around out-of-line VM calls. Thanks for giving me the code location of this in IRC. I will submit a bug and use movups to store/load the full XMM register for x64 and x86 so that it works for Float32x4 registers in the future. > > >Dan wrote a patch to > >allocate and spill Float32x4 > >(https://bugzilla.mozilla.org/show_bug.cgi?id=947711), could you give > >review comments there? > > This is fine as long as they remain on the stack, but if they are in > registers then this would be incomplete as we will read 128 bits out > of 64 bits spills. Can you ask me for feedback on these patches? > > -- > Nicolas B. Pierron > _______________________________________________ > dev-tech-js-engine-internals mailing list > [email protected] > https://lists.mozilla.org/listinfo/dev-tech-js-engine-internals _______________________________________________ dev-tech-js-engine-internals mailing list [email protected] https://lists.mozilla.org/listinfo/dev-tech-js-engine-internals
