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As I understand it, when Sun developed Java, they ditched Self. Some of the Self team left, and created a Smalltalk VM using the Self VM techniques called Stron

As I understand it, when Sun developed Java, they ditched Self. Some of the Self team left, and created a Smalltalk VM using the Self VM techniques called Strongtalk. Sun belatedly realised they needed a fast VM, and rehired the team which formed the basis of the HotspotVM.

saurik 6y ago
That same team--led by the same guy: Lars Bak--was later hired by Google to develop v8 for Chrome and later built the VM for Dart (which has some really powerful features in static object layout and AOT support). Virtually every single seminal VM for decades was designed by this same group of people, with almost all other VMs you see just borrowing those same techniques to apply to other languages.
- russellallen 6y ago
  It’s an era only just ending now with the emergence of Truffle/Graal.
- pjmlp 6y ago
  And then Lars Bak left, I guess desilusioned with out things turned out for Dart, and is now doing "Dart for IoT" back in Denmark. https://www.youtube.com/watch?v=mPna6D21Eqg https://www.youtube.com/watch?v=mPna6D21Eqg
pinewurst 6y ago
ParcPlace’s Smalltalk VMs (PS and HPS) were JIT VMs in the same period (if not a bit earlier).
- eternalban 6y ago
  quote: "Before I started down the path of making Java fast, I was told "you can't JIT code that will touch a static compiler" . Afterwards: all new languages start with the assumption "we can JIT this" in the implementation." - Cliff Click's LinkedIn (1997-2002 @ Sun Micro)
- jecel 6y ago
  PS and HPS did indeed implement the dynamic compilation technologies created by L Peter Deutsch and Allen Shiffman at Xerox Parc. Self 1 and 2 were even fancier JITs by Craig Chambers, but Self 3 (and 4) by Urs Hölzle implemented adaptive compilation which uses an initial simple compiler for all called code and then a second fancy compiler for the hot spots. The execution of the code from the first compiler not only measured execution to find the hot spots but also accumulated type information to make the second compiler simpler (compared to the type inference in the Self 2 compiler). I gave a talk about this a few months ago: "Adaptive Compilation" - video: https://www.youtube.com/watch?v=TO53xFACfuQ https://www.youtube.com/watch?v=TO53xFACfuQ pdf slides: http://www.merlintec.com/download/2019_slides_jecel_fast2v2.pdf http://www.merlintec.com/download/2019_slides_jecel_fast2v2.... open office slides: http://www.merlintec.com/download/2019_slides_jecel_fast2v2.odp http://www.merlintec.com/download/2019_slides_jecel_fast2v2.... As the name of the Sun Java VM indicates, it is an adaptive compiler like StrongTalk and Self 3/4.
cardiffspaceman 6y ago
One of my favorite JIT techniques from the era is PIC, polymorphic inline caching. A method send (virtual function call) would be statically coded to call the hottest implementation of a virtual function. The virtual function itself would check that the incoming object had the right type. If not, the fully polymorphic dispatch mechanism would kick in. Statistics would be tracked and could lead to a decision to overwrite the static call with a call to the new hot implementation. I think this was demonstrated on Strongtalk.

saurik 6y ago

That same team--led by the same guy: Lars Bak--was later hired by Google to develop v8 for Chrome and later built the VM for Dart (which has some really powerful features in static object layout and AOT support). Virtually every single seminal VM for decades was designed by this same group of people, with almost all other VMs you see just borrowing those same techniques to apply to other languages.

russellallen 6y ago
It’s an era only just ending now with the emergence of Truffle/Graal.
pjmlp 6y ago
And then Lars Bak left, I guess desilusioned with out things turned out for Dart, and is now doing "Dart for IoT" back in Denmark. https://www.youtube.com/watch?v=mPna6D21Eqg https://www.youtube.com/watch?v=mPna6D21Eqg

pinewurst 6y ago

ParcPlace’s Smalltalk VMs (PS and HPS) were JIT VMs in the same period (if not a bit earlier).

eternalban 6y ago
quote: "Before I started down the path of making Java fast, I was told "you can't JIT code that will touch a static compiler" . Afterwards: all new languages start with the assumption "we can JIT this" in the implementation." - Cliff Click's LinkedIn (1997-2002 @ Sun Micro)
jecel 6y ago
PS and HPS did indeed implement the dynamic compilation technologies created by L Peter Deutsch and Allen Shiffman at Xerox Parc. Self 1 and 2 were even fancier JITs by Craig Chambers, but Self 3 (and 4) by Urs Hölzle implemented adaptive compilation which uses an initial simple compiler for all called code and then a second fancy compiler for the hot spots. The execution of the code from the first compiler not only measured execution to find the hot spots but also accumulated type information to make the second compiler simpler (compared to the type inference in the Self 2 compiler). I gave a talk about this a few months ago: "Adaptive Compilation" - video: https://www.youtube.com/watch?v=TO53xFACfuQ https://www.youtube.com/watch?v=TO53xFACfuQ pdf slides: http://www.merlintec.com/download/2019_slides_jecel_fast2v2.pdf http://www.merlintec.com/download/2019_slides_jecel_fast2v2.... open office slides: http://www.merlintec.com/download/2019_slides_jecel_fast2v2.odp http://www.merlintec.com/download/2019_slides_jecel_fast2v2.... As the name of the Sun Java VM indicates, it is an adaptive compiler like StrongTalk and Self 3/4.

cardiffspaceman 6y ago

One of my favorite JIT techniques from the era is PIC, polymorphic inline caching. A method send (virtual function call) would be statically coded to call the hottest implementation of a virtual function. The virtual function itself would check that the incoming object had the right type. If not, the fully polymorphic dispatch mechanism would kick in. Statistics would be tracked and could lead to a decision to overwrite the static call with a call to the new hot implementation. I think this was demonstrated on Strongtalk.