jit

问题 I already worked with -XX:+PrintCompilation , and I know the basic techniques of the JIT-compiler and why JIT-compilation is used. Yet I still have not found out how the JVM decides to JIT-compile a method, i.e. "when the right time has come to JIT-compile a method". Am I right in the assumption that every method starts being interpreted, and as long as it is not categorized as "hot method" it will not be compiled? I have something in the back of my head that I read that a method is

问题 I've been thinking about nested try/catch statements and started to think about under which conditions, if any, the JIT can perform an optimization or simplification of the compiled IL. To illustrate, consider the following functionally-equivalent representations of an exception handler. // Nested try/catch try { try { try { foo(); } catch(ExceptionTypeA) { } } catch(ExceptionTypeB) { } } catch(ExceptionTypeC) { } // Linear try/catch try { foo(); } catch(ExceptionTypeA) { } catch

问题 I am trying to create an ASP.Net Web application that stores it's "content" (ASPX/ASCX and assemblies) somewhere other than the file system (Inside a service, for example) and loads them in dynamically as required. I have successfully created a VirtualPathProvider that takes care of reading ASPX/Master/ASCX files from alternate locations but I am running into problems when those ASPX pages Inherit a class - ie: when they have code behind. Thanks to answers in another question I am now

问题 I use Java primarily for writing pet projects, which are idle most of the time. And after being idle for hours/days response time increases to seconds (up to 10s), then slowly decreases back to 200-300ms. As far as I understand, this happens because of JIT deoptimization (optimized code becomes marked as a zombie, removed and later compiled again). Is there any way to forbid JVM to deoptimize code unless code cache is full? Java 9's AOT looks like the best solution for this case, but I still

问题 I have a really awkward problem. I have build my app for iOS and tested it on all emulators and it works fine. I have installed it on a device (iPhone 6 plus) and that works fine as well. However, when I submit it to the app store, the feedback is that it crashes on launch on all devices. The crash log attached shows this error; Unhandled Exception: System.ExecutionEngineException: Attempting to JIT compile method 'GalaSoft.MvvmLight.Messaging.Messenger:get_Default ()' while running with -

问题 To provide TLS support to orcjit, I'm like to transforom llvm::Modules without TLS emulation to ones that emulateTLS and depend on a Runtime. Similar functionality is already implemented in TargetLowering::LowerToTLSEmulatedModel , however it does not operate on IR. So, how can i implement and perform this operation as an llvm::Pass ? 来源： https://stackoverflow.com/questions/42163796/how-to-perform-targetlowering-in-a-ir-trasformation-pass

问题 From what I have read java (usually) seems to compile java to not very (is at all?) optimised java bytecode, leaving it to the jit to optimise. Is this true? And if it is has there been any exploration (possibly in alternative implementations) of getting the compiler to optimise the code so the jit has less work to do (is this possible)? Also many people seem to have a dislike for native code generation (sometimes referred to as ahead of time compilation) for Java (and many other high level

问题 Disclaimer: Please no advice concerning premature optimization. I'm just curious. Imagine I want to make sure that some objects referenced by a field can be garbage collected ASAP. I'm using a home-made singly linked list like this class BigData { byte[] someBigArray; BigData next; } private BigData bigData; and iterate like this while (bigData != null) { process(bigData); bigData = bigData.next; } Is the JIT free to change it like follows? BigData tmp = bigData; while (tmp != null) { process

问题 Disclaimer: Please no advice concerning premature optimization. I'm just curious. Imagine I want to make sure that some objects referenced by a field can be garbage collected ASAP. I'm using a home-made singly linked list like this class BigData { byte[] someBigArray; BigData next; } private BigData bigData; and iterate like this while (bigData != null) { process(bigData); bigData = bigData.next; } Is the JIT free to change it like follows? BigData tmp = bigData; while (tmp != null) { process

问题 Psyco is a specialising compiler for Python. The documentation states Psyco can and will use large amounts of memory. What are the main reasons for this memory usage? Is substantial memory overhead a feature of JIT compilers in general? Edit: Thanks for the answers so far. There are three likely contenders. Writing multiple specialised blocks, each of which require memory Overhead due to compiling source on the fly Overhead due to capturing enough data to do dynamic profiling The question is,