similar to: [LLVMdev] RFC: MCJIT enhancements

I have some vision about Object Caching. A client, which is interested in object caching, will need some help from compiler and LLVM side. The object file, located on disk, should contain information that allows to decide – rebuild or not rebuild. The client (a backend engine, which translates IR to JIT) compares data from object file, found on disk and module IR. The information that object

This sounds interesting, but strikes me as significantly outside the scope of the MCJIT itself. That is, this is the sort of thing a client application or framework would build on top of the MCJIT. -Jim On Jul 30, 2012, at 6:20 AM, "Demikhovsky, Elena" <elena.demikhovsky at intel.com> wrote: > I have some vision about Object Caching. > > A client, which is interested

> So I'm using "llvm/ExecutionEngine/MCJIT.h" instead of > "llvm/ExecutionEngine/JIT.h", and I've added setUseMCJIT(true) to > EngineBuilder, but what actually happens is: > > LLVM ERROR: Target does not support MC emission! > > Do I need to do anything else? IIRC, this error might be due to not linking against the MCJIT library component. Add the

Following along from lli code, if you add a call to InitializeNativeTargetAsmPrinter() during setup, it gets a bit farther and crashes rather than issuing that error. (Rebuilding with debugging symbols now to dig into it further…) -matt Program received signal EXC_BAD_ACCESS, Could not access memory. Reason: KERN_INVALID_ADDRESS at address: 0x0000000000000000 0x000000010000349e in

Hi Lang, Yeah, I remember this case. Basically what’s happening is that there are relocations for ELF on x86 that use a value that is present in the object image as part of the calculation for the final value that goes in the same location. If you ever find yourself applying relocations for a second time (for instance, because the loaded object location is remapped for out-of-proc execution)

Hi Paul, I'm surprised to hear that you aren't seeing any adverse effects. As I understand it, the memory for the function pointer returned by getPointerToFunction is owned by the JITMemoryManager which was used in creating the ExecutionEngine. In the case of the legacy JIT engine, the JITMemoryManager is owned by the JITEmitter which in turn is owned by the JIT ExecutionEngine. In the

Given: typedef MyClass* (*jit_fn_ptr_type)(); MyClass* set_fn( llvm::Function *fn ) { // create an ExecutionEngine 'exec' ... jit_fn_ptr_type fn_ptr = (jit_fn_ptr_type)exec->getPointerToFunction( fn ); return fn_ptr(); } After I call getPointerToFunction() to obtain the pointer to the JIT'd function and fun the function (that will produce an instance of MyClass on the

Hi all, I'm trying to add pre-compiled object cache to my run-time. I've implemented the object cache as follow: class EngineObjectCache : public llvm::ObjectCache { private: std::unordered_map<std::string, std::unique_ptr<llvm::MemoryBuffer>> CachedObjs; public: virtual void notifyObjectCompiled(const llvm::Module *M, llvm::MemoryBufferRef Obj) { auto id =

Ah, now that makes sense. Guess I was a little over-eager with my bugreport. Thanks! :) However, I am now running into the same Problem as Matt ("Target does not support MC emission!"). Best, Ralf Am 25.08.2011 19:32, schrieb Bruno Cardoso Lopes: > Hi Ralf, > > FYI, old JIT doesn't support AVX at all, no encoding info, etc... The > only way to use AVX+JIT is using

I have a legacy C++ application that constructs a tree of C++ objects (an iterator tree to implement a query language). I am trying to use LLVM to "serialize" the state of this tree to disk for later loading and execution (or "compile" it to disk, if you prefer). Each of the C++ iterator objects now has a codegen() member function that adds to the LLVM code of an

Hi Ralf, FYI, old JIT doesn't support AVX at all, no encoding info, etc... The only way to use AVX+JIT is using MCJIT, which contains the correct encoding, but unfortunately the framework isn't good yet as the old one is. On Thu, Aug 25, 2011 at 10:12 AM, Ralf Karrenberg <Chareos at gmx.de> wrote: > Hi Matt, > > I am unsure about MCJIT, but I guess the problem is the same.

The main problem, as I see it, is that there's no way for the memory manager to know when it can safely change the protection state of sections apart from making assumptions about the implementation of MCJIT (namely that it will generate code on construction) and receiving some sort of notification outside the standard interface. I believe there's also no provision for handling read-only

When you talk about lazy compilation, it isn't clear to me if you mean the single compilation step that produces a loadable module being delayed until a function is requested or the full-blown, legacy-JIT style lazy compilation of individual functions within a module being JITed only when needed. If the latter, it isn't clear to me how that would be done within the MC model. That's a

Somewhat, yes. The MCJIT currently doesn't support lazy compilation in general, and things like notifications back (via the memory manager) when new sections have been produced and such needs to be part of that. Your'e right that, for now, the underlying assumption is that everything gets built up at once. The following is mostly stuff we've talked about before, but just to make sure

I am implementing ELFObject class for MCJIT to be able to run ELFs on ELF-platforms. One thing bothers me: I see that the RTDyldMemoryManager-based allocator is always passed to MCJIT and to RuntimeDyld classes from outside. This enforces the approach that memory will be allocated function by function with startFunctionBody/endFunctionBody. This maybe was good for the old JIT, but not for

Hi Matt, Philip, You could get the data you want by recording the addresses returned by the allocateCodeSection and allocateDataSection methods on your RTDyldMemoryManager, then disassembling those sections after you've called resolveRelocations. That's a little unsatisfying though. For one thing, unless you very carefully maintain the association with the original object via

I'm not sure I have a clear picture of what you're JIT'ing. If any of the JIT'ed functions call other JIT'ed functions, it may be difficult to find all the dependencies of a functions and recreate them correctly on a subsequent load. Even if the JIT'ed functions only call non-JIT'ed functions, I think you'd need some confidence that the address of the called

Thanks! Currently using MCJIT. But migration to ORC is on my TODO list. - Paweł On Thu, May 12, 2016 at 8:30 PM Lang Hames <lhames at gmail.com> wrote: > Hi Pawel, > > Option (1) and (3) are very similar, but using custom resolution (option > 3) guarantees that JIT'd code can't accidentally end up depending on > functions in your JIT that you didn't mean to

Hi I’ve previously used the ExecutionEngine::addGlobalMapping to make existing functions available to my JITed code. I’m currently using ORC, as MCJIT does not appear to be maintained any longer (the kaleidoscope examples have not worked for some time with MCJIT). I’m using just the basic ORC CompileLayer directly. So, I’ve essentially copied the ExecutionEngine::addGlobalMapping related

Hi guys. I found a little bug in implementation of MCJIT. I noticed that when I added object file (with all needed debug information) to lli by using -extra-object flag, it's impossible to debug it with gdb. Object file is in ELF format generated by llc. It is properly loaded by mcjit. I noticed that the reason is probably in lack of calling "registerWithDebugger()" after object