You don’t use malloc for that. Why would you anyway, in a C++ program? You also don’t use new for executable memory, however. There’s the Windows-specific VirtualAlloc function to reserve memory which you then mark as executable with the VirtualProtect function applying, for instance, the PAGE_EXECUTE_READ flag. When you have done that, you can cast … Read more
You could use MethodImplAttribute and specify MethodImplOptions.NoInlining. [MethodImpl(MethodImplOptions.NoInlining)] void YourMethod() { // do something } Note that this still doesn’t guarantee that you can get at the actual calling method as seen in the source code. Your method won’t be inlined, but your method’s caller could be inlined into its own caller, etc etc.
Without resorting to cut’n’paste of the link that @MYYN posted, I suspect this is because the optimisations that the JVM performs are not static, but rather dynamic, based on the data patterns as well as code patterns. It’s likely that these data patterns will change during the application’s lifetime, rendering the cached optimisations less than … Read more
In general, Just-in-time compilation refers to compiling native code at runtime and executing it instead of (or in addition to) interpreting. Some VMs, such as Google V8, don’t even have an interpreter; they JIT compile every function that gets executed (with varying degrees of optimization). On Stack Replacement (OSR) is a technique for switching between … Read more
Yes, HotSpot JIT can eliminate redundant allocations in a local context. This optimization is provided by the Escape Analysis enabled since JDK 6u23. It is often confused with on-stack allocation, but in fact it is much more powerful, since it allows not only to allocate objects on stack, but to eliminate allocation altogether by replacing … Read more
JIT triggers AFTER a certain piece of code has been executed many times. The HotSpot JVM will try to identify “hot spots” in your code. Hot spots are pieces of your code that are executed many many times. To do this, the JVM will “count” the executions of various instructions, and when it determines a … Read more
NGen will only help startup time – it doesn’t make the code execute any faster than it would after JITting. Indeed, I believe there are some optimizations which NGen doesn’t do but the JIT does. So, the main question is: do you have an issue with startup time? I don’t know how much of an … Read more
Note: this answer is on a “per-run” context. The code is normally JITted each time you run the program. Using ngen or .NET Native changes that story, too… Unlike HotSpot, the CLR JIT always compiles exactly once per run. It never interprets, and it never recompiles with heavier optimisation than before based on actual usage. … Read more
Yes, HotSpot JVM is kind of “cheating”, because it has a special version of some BigInteger methods that you won’t find in Java code. These methods are called JVM intrinsics. In particular, BigInteger.multiplyToLen is an intrinsic method in HotSpot. There is a special hand-coded assembly implementation in JVM source base, but only for x86-64 architecture. … Read more
It is a jitter implementation detail, the x86 and x64 jitters have subtly different rules. This is casually documented in blog posts of team members that worked on the jitter but the teams certainly reserve the right to alter the rules. Looks like you already found them. Inlining methods from other assemblies is most certainly … Read more