"JIT Compiler From the Ground Up" [AtA]
While Java programs are deployed as bytecode, performance-relevant code will be compiled, at run time, to machine code whose performance rivals that of any other platform. In the HotSpot JVM, this is the job of the just-in-time compilers C1 and C2 and between speculation and traps, inlining and constant folding, escape analysis and scalar replacement (and many more), they apply a number of heuristics, analyses, and transformations to achieve that. This requires expertise, careful research, thorough testing, and regular reevaluations of old assumptions.
In this "Ask the Architects" episode of…
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