Which alternatives? Sbcl:
- Requires manual type annotations to achieve remotely reasonable performance
- Does no interesting optimisations around method dispatch
- Chokes on code which reassigns variables
- Doesn't model memory (sroa, store forwarding, alias analysis, concurrency...)
- Doesn't do code motion
- Has a decent, but not particularly good gc
Hotspot hits on all of these points.
It's true that if you hand-hold the compiler, you can get fairly reasonable machine code out of it, same as you can do with some c compilers these days. But it's 80s technology and it shows.
- Requires manual type annotations to achieve remotely reasonable performance
- Does no interesting optimisations around method dispatch
- Chokes on code which reassigns variables
- Doesn't model memory (sroa, store forwarding, alias analysis, concurrency...)
- Doesn't do code motion
- Has a decent, but not particularly good gc
Hotspot hits on all of these points.
It's true that if you hand-hold the compiler, you can get fairly reasonable machine code out of it, same as you can do with some c compilers these days. But it's 80s technology and it shows.