jit

问题 I'm receiving the following error on my iOS device: ExecutionEngineException: Attempting to JIT compile method 'System.Linq.OrderedEnumerable 1<System.Collections.Generic.KeyValuePair 2>:GetEnumerator ()' while running with --aot-only. I'm using Unity3D, and I know the error is caused because LINQ expressions have issues with ordering value types when compiling Unity to iOS. Because (I think) that the expression attempts to use reflection to instantiate a new type which implements the

问题 I'm starting this question after a discussion which started (in comments) on another StackOverflow question, and I'm intrigued to know the answer. Considering the following expression: var objects = RequestObjects.Where(r => r.RequestDate > ListOfDates.Max()); Will there be any (performance) advantage of moving the evaluation of ListOfDates.Max() out of the Where clause in this case, or will 1. the compiler or 2. JIT optimize this away? I believe C# will only do constant folding at compile

问题 Whilst running test code from this question and fiddling with the JVM's thread stack size, I found that results were not necessarily repeatable: there were values of stack size for which the program would sometimes throw java.lang.StackOverflowError , but sometimes not . My question is: "What is causing the variation in stack space consumption?" Also, can an interrupt's stack be put on this program's main thread? Will results be similarly non-deterministic for other JVM implementations and/or

问题 I'm using angular.io quickstart seed: https://angular.io/docs/ts/latest/guide/setup.html I'm using Angular4 with typescript JIT Currently I would like to add lodash so I can use this in my component and then do an npm run build e.g. tsc -p src/" and not get any errors My component: import { Component } from '@angular/core'; import * as _ from 'lodash'; @Component({ moduleId: module.id, selector: 'HomeComponent', templateUrl: 'home.component.html' }) export class HomeComponent { constructor()

问题 This question already has answers here : Closed 7 years ago . Possible Duplicate: Why doesn't the JVM cache JIT compiled code? I understand that JIT compilation is compilation to native code using hotspot mechanisms, which can be very very fast as it is optimization to the OS, Hardwards, etc. My question is, why does Java not store that JIT complied code somewhere in file and use the same for future purposes? This can reduce the 'initial warm-up' time as well. Please let me know what I am

问题 Being that properties are just methods under the hood, it's understandable that the performance of any logic they might perform may or may not improve performance - so it's understandable why the JIT needs to check if methods are worth inlining. Automatic properties however (as far as I understand) cannot have any logic, and simply return or set the value of the underlying field. As far as I know, automatic properties are treated by the Compiler and the JIT just like any other methods.

问题 I am working on a JIT that uses LLVM. The language has a small run-time written in C++ which I compile down to LLVM IR using clang clang++ runtime.cu --cuda-gpu-arch=sm_50 -c -emit-llvm and then load the *.bc files, generate additional IR, and execute on the fly. The reason for the CUDA stuff is that I want to add some GPU acceleration to the runtime. However, this introduces CUDA specific external functions which gives errors such as: LLVM ERROR: Program used external function

问题 No The JIT compiler may "transform" the bytecode into something completely different anyway. It will lead you to do premature optimization. Yes You do not know which method will be compiled by the JIT, so it is better if you optimize them all. It will make you a better Java programmer. I am asking without really knowing (obviously) so feel free to redirect to JIT hyperlinks. 回答1: Yes, but to a certain extent -- it's good as an educational opportunity to see what is going on under the hood,

问题 Is there a performance difference between using Collections.emptyList() or an empty ArrayList , especially when using a JIT compiler? I could imagine that - for example - the JIT compiler doesn't do inlining or static method calls because the executed method depends on the type. Edit I know that Collections.emptyList() returns an immutable list while ArrayList is mutable object. What I mean is that if I pass one or the other to a method as a parameter and the method doesn't modify the list

问题 I just read that Android has a 450% performance improvement because it added a JIT compiler , I know what JIT is, but I don't really understand why is it faster than normal compiled code? or what's the difference with the older approach from the Android platform (the Java like run compiled bytecode). Thanks! EDIT: This is hugely interesting, thanks!, I wish I could pick every answer as correct :) 回答1: First a disclaimer, I'm not at all familiar with Android. Anyway... There are two