[Vm-dev] Re: New Cog VMs available as per VMMaker.oscog-eem.1679/r3602

Eliot Miranda eliot.miranda at gmail.com
Mon Feb 15 19:42:36 UTC 2016

Hi Levente,

    I'm optimistic that these VMs will fix the stability problems you've
been having with VMs later than VM.r3397.  I had destabilised Slang in
getting the 64-bit VM to generate and finally understood what I'd done late
last year.  Slang is now much more stable and so let me ask you to test and
see if the instabilities you've experienced are addressed or not.  As they
say, I'm all ears.

On Mon, Feb 15, 2016 at 11:39 AM, Eliot Miranda <eliot.miranda at gmail.com>

> Hi All,
>     first of all, apologies for the long wait for new VMs.  I know there
> are bugs that these VMs address and that it's been 5 months since VMs were
> last made is something I regret.  The wait was due to my developing the
> 64-bit Spur Cog JIT VM which required surgery not just to the Cogit but
> also to Slang.  I beg your forgiveness.
>    Secondly, the Mac VMs are much changed, using John McIntosh's Cocoa
> support libraries.  The old Carbon UI VMs are history.  That means that Cog
> supports building on contemporary Mac OS releases.  These VMs were built on
> 10.9; I like the 3D look much more than the 10.10 one ;-).  The VMs are
> also signed, so installing them should be easier.
>   Thirdly, these VMs include 64-bit JIT support.  There is an updated
> squeak trunk image at http://www.mirandabanda.org/files/Cog/SpurImages
> for you to try.  As yet the 64-bit Vms do not include an FFI plugin.  I
> hope to rectify this soon.
>    Finally I have included Pharo Mac VMs, not to displace the official
> Pharo VMs, but to test my build process.  I hope that in very few months
> the svn repository will be moed to githup and that Esteban and I will build
> official VMs from the same repository.
> The VMs are here: http://www.mirandabanda.org/files/Cog/VM/VM.r3602
> CogVM binaries as per VMMaker.oscog-eem.1679/r3602
> Include 64-bit Spur VMs for Mac OS X x64 and Linux x64. N.B. As yet these
> VMs
> lack FFI support.
> Move all Mac OS X VMs to the Cocoa libraries.  Minimum supported version
> should
> be 10.6.x.  The Mac OS X VMs are signed and so should install properly
> without
> having to disable the launch security checks.
> Bug Fixes and Improvements:
> General:
> Add vmParameter 20 to answer the utc microseconds at startup.
> CoInterpreter:
> Remove the atCache from the CoInterpreter.  It's of little benefit given
> the
> Cogit.
> ceSend: et al need to add looked up methods to the method cache, otherwise
> methods only found through machine code sends will not be jitted.
> Fix slip in maybeSelectorOfMethod: which will improve back traces
> including methods containing pragmas (including primitives).
> Modify secret primtiive 161, primitiveSetIdentityHash so that with 0 args
> it
> answers whether an object has an identity hash.  This is vacuously true
> for V3,
> but is meaningful in Spur.
> Cogit:
> Fix /horrible/ bug with primitive error codes and fixups.  The adjustment
> of the
> initialPC to skip the primitive and error code, if any, was done after
> generating fixups for backward branches, and hence these branches were
> bogus.
> Object>>shallowCopy in Spur is subject to this, but amazingly enough it
> has not
> surfaced before now.  Fix this by adjusting the initialPC before scanMethod
> scans for fixups.
> Fix bug in Spur machine-code at:put: on 32-bit bits objects; method failed
> to
> fail for negative values.
> Fill unused portions of methods with the stop instruction, not nop.
> Explicitly initialize the code zone with stops. Explicitly clear the
> reclaimed portion of the method zone after a compaction.
> Include the reclaimed portion of the method zone in the I-cache flush
> after a compaction: no point in leaving it in cache since it isn't a
> valid call/jump target.
> Spur:
> Maintain the survivor count on scavenge.
> Fix start up of images containing >= 16 segments.  The old code assumed
> numSegments < 16 and failed to grow the segment records, resulting in
> objects
> in segments greater than 15 to not be swizzled, and a resulting crash.
> Spur Cogit: Support CompiledMethod indexing in genPrimitiveAt[Put].  Hence
> fix
> the regression in at:[put:] whereby in Spur one could access the literals
> part
> of a method as bytes.
> Add a machine-code primitive for objectAt: to provide fast literal and
> header
> access on Spur.
> Add 16-bit indexability to Spur.  Generate slimmer code for
> positive32BitValueOf: on 64-bit Spur.
> Fix a bug with out-of-place two-way become, which got the hash copy the
> wrong
> way round.  By default, the hash stays with the reference in two-way
> become.
> Fix what appears to be a compiler bug with in-place two-way-become by
> treating
> the headers to be swapped so that remembered flags are swapped and hash
> bits
> are swapped if required. This fixes a bug with in-place two-way become of
> objects that are the same size on the heap.  One object's contents would
> not
> be updated correctly.
> Implement ephemeron queue primitive.  Add an image flag that controls the
> finalization support (StackInterpreter instVar newFinalization).  If unset,
> finalization is as currently expected; WeakArray finalizes all WeakArrays
> in
> its registries on each finalization (which does not scale!).  If set, then
> both
> fired ephemerons and bereaved weak arrays are added to the finalization
> queue
> and the finalization semaphore is signalled.  In this regime the image is
> expected to send mourn to each element of the queue, and weak arrays will
> send
> themselves finalize in mourn, side-stepping the finalizeValues steps and
> rendering WeakArray's FinalizationDependents and WeakRegistry obsolete.
> The bit is set via
>     Smalltalk vmParameterAt: 48
>               put: ((Smalltalk vmParameterAt: 48) bitOr: 64).
> Slang:
> Fix bad regression in type inference from VMMaker.oscog-eem.1587.
> returnTypeForSend:in: can only default return types to sqInt for unknown
> selectors.  The rewrite in VMMaker.oscog-eem.1587 inadvertently defaulted
> the
> return type of known methods whose return type was yet to be determined to
> sqInt.  The fix is to only default to sqInt if there is no known method
> for the
> given selector.  This fixes, for instance, the weird flipping of the type
> of
> 32-bit Spur's headerWhileForwardingOf:,which should always be #sqLong.
> Fix bad bug in type inferrence.  Avoid computing variable and return types
> prematurely i.e. don't derive types from as-yet-untyped methods.
> Fix baaaad bug in node:typeCompatibleWith:inliningInto:in: which was
> looking
> up the type of the formal parameter in inlining in the target method, not
> the
> method being inlined!
> Newspeak:
> Fix bug in MNU for cogged dynamic super sends - should start looking for
> #doesNotUnderstand: in the superclass not the receiver class. Unify MNU
> lookup between absent and present receiver sends as a result.
> Further fix outer send MNU by not confusing lkupClass and lkupClassTag.
> Push setting lkupClassTag down to clarify it is for new cache entries.
> Plugins:
> Fix the FilePlugin's unnecessary fullGC on Spur.
> Include the file sync prim in the FilePrims plugin.
> ThreadedFFIPlugin:
> - ExternalAddress now are taken correctly (nor as ByteArray or Alien,
> because
>   they are different beasts).
> - allow pushing of pointers to any type (into a ByteArray, an
> ExternalAddress
>   or an Alien), to allow passing parameters style int*, float*, etc.
> - allow reading in memory to allow read chunks of ByteArray
> Added ThreadedFFIPlugin>>#primitiveLoadSymbolFromModule (copy and adapt
> from
> IA32ABIPlugin).
> Fix coercion problems on FFI plugin (IA32 & ARM)
> - character were not correctly mapped back
> - floats were not being well checked
> - external addressed needs to be treated as aliens for the purpose of
> coercing
>   them as pointers (bad regression by Eliot)
> Alien Plugins:
> Fix missing primitive failure for Alien typeAt: 0 [put:].
> Add word accessors to Alien.
> _,,,^..^,,,_
> best, Eliot

best, Eliot
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