similar to: ORC JIT Weekly #14 -- Removable code

Hi All, This week I've been focused on removing some of the blockers for people transitioning from ORCv1 to ORCv2. Issue #1 (http://llvm.org/PR40074, http://llvm.org/PR44337): When LLVM codegens floating point constants for COFF we produce named constant pool entries of the form __real@<bitval>. These are stored in COFF COMDAT sections [1] which allow duplicate symbol definitions to

Hi All, In the interests of improving visibility into ORC JIT development I'm going to try writing weekly status updates for the community. I hope they will provide insight into the design and state of development of LLVM's JIT APIs, as well as serving as a convenient space for discussions among LLVM's large and growing community of JIT API users. The length and detail will vary

Hi Dave, Yep. This is JITLink specific, so we could only have observed it on MachO x86-64 or arm64 until recently. It takes a little bit of poking to get IR to produce a zero-lengh section on MachO, but not much. Jared Wyles recently contributed an initial JITLink ELF implementation, so the fix seems timely -- we might have been about to see more of it. -- Lang. On Fri, Jun 19, 2020 at 4:02 PM

Hello, I am trying to run this basic C++ hello-world code in my iOS app that has LLVM libraries linked in (the app runs on the actual device - iPad Pro, iOS 13.4.1). #include <iostream> int main (int argh, char *argv[]) { std::cout << "Hello World!" << std::endl; return 0; } So below is the break down of the steps that I do: First I compile this code to an

Hey Lang, I would be really happy to only have one LLJIT instance and using multiple JITDylibs. However… it seems like that I don’t know enough to use them. So I wonder… 1. When I add Module A to JITDylib A and Module B to JITDylib B – where will those look for undefined symbols? Will Module A for example: will it only search itself and the MainDylib? Or would it also search in JITDylib B?

Hi Lang, Please see below is the trace. -- Thanks, Igor *2020-06-06 12:05:21.016705-0400 CppDevProCompiler[6613:3000073] Running...* *jitLink_MachO: magic = 0xfeedfacf, identifier = "llvm-link.submodule-jitted-objectbuffer"* *jitLink_MachO: cputype = 0x0100000c, cpusubtype = 0x00000000* *Creating normalized sections...* * __text: 0x0000000000000000 -- 0x0000000000000064, align:

Hi Andres, I also want to highlight the necessity of some form of C API, that others > already have. > <snip> > It's fine if the set of "somewhat stable" C APIs doesn't provide all the > possible features, though. Ok. This got me thinking about what a simple LLJIT API should look like. I have posted a sketch of a possible API on http://llvm.org/PR31103 . I

Hi All, There was only one interesting ORC-specific commit this week: A new example showing how to initialize and de-initialize JITDylibs has been added in llvm/examples/OrcV2Examples/LLJITWithInitializers. The Extensible RTTI system (https://reviews.llvm.org/D39111) that I posted a while back has landed. While this is not ORC specific, I expect it to be used in upcoming patches to allow ORC

Hi All, The general initializer support patch has landed (see 85fb997659b plus follow up fixes). Some quick background: Until now ORC, like MCJIT, has handled static initializer discovery by searching for llvm.global_ctors and llvm.global_dtors arrays in the IR added to the JIT. This approach suffers from several drawbacks: 1) It provides no built-in support for other program representations:

Hi, I'm working on a runtime autotuner that utilizes ORCv2 JIT (I'm closely tracking tip-of-tree), so linking new object files and patching in the new function(s) will happen frequently. One of the concerns my runtime system has is the ability to do one of the following: (1) replacement of the contents of a JITDylib with a new object file [to provide semi-space GC-style reclaiming], (2)

Hi All, I've updated the orcv1 removal branch ( https://github.com/lhames/llvm-project/tree/orcv1-removal) with an initial patch for removable code. If anyone wants to follow along with the development or share thoughts on the design you're very welcome to. I'll be adding tests and comments this week, but for anyone who wants to take an early look the main elements are defined in

Hi All, Everything is landing all at once, just not in the mainline... yet. As discussed in http://lists.llvm.org/pipermail/llvm-dev/2020-September/144885.html: OrcV1 will be removed very soon. I have posted a branch with the removal, "orcv1-removal", in my llvm fork at https://github.com/lhames/llvm-project. In addition to removing OrcV1, the orcv1-removal branch also contains a

Hello, I recently hit an issue when JIT'ing my generated IR using llvm::orc::LLJIT. My IR contains the following definition of a global variable: > $_ZZ23TestStaticVarInFunctionbE1x = comdat any > @_ZZ23TestStaticVarInFunctionbE1x = linkonce_odr dso_local global i32 123, > comdat, align 4 > And in my host process, there exists the same symbol. I would expect LLJIT to resolve the

Hi Andres, Cool!I assume this works on "non-native" jitlink platforms as well? Or > just mach? This framework is totally materializer agnostic -- It works for ObjectLinkingLayer (JITLink), RTDyldObjectLinkingLayer (RuntimeDyld), and even materializers that aren't emitted via a linker (e.g. stubs and callbacks). Looks like there's not yet a C API yet - not a problem, just

Hey Lang, Woah! That mail contains a lot of information and things I never tried yet… Actually… the entire MaterializationUnit and MaterializationResponsibility part is… quite… overwhelming >O< With “pop up” I mean… the process which is waiting for Module “Planschi” to “pop up” can not do a thing about it. It just waits until there is an table entry for it, indicating that the object file

Hi All, There was no update last week -- I'm still trying to get back into a regular schedule. Open-source changes since the last update were: (1) Some bug fixes for JITLink MachO / arm64 support (PAGE21/PAGEOFF12 now handle addends correctly). (2) llvm-jitlink now supports loading archives as well as relocatable objects. (3) llvm-jitlink now supports basic object-file level mocking and

Hey Lang, > Do you mean that the object file is produced by another process and is being loaded into your JIT process for execution, or that you want your JIT to produce code for several different processes? These are different problems with different solutions. I'll wait until I understand your use case to answer further. In the current state we don’t have a JIT only an handcrafted object

Hi Lang, Thank you for your answer! This helped me again a lot!! Also that ResourceTracker is a really neat feature! Looking forward to it! :3 I changed the title cause… there is another issue I have (sorry about that…) I’m finally allowed to investigate the ORC JIT for integration into our system, which meant I got a few days to actually play around with it. However, another problem arise

Hi All, The initializer patch review at https://reviews.llvm.org/D74300 has been updated. The new version contains a MachOPlatform implementation that demonstrates how Platforms and ObjectLinkingLayer::Plugins can work together to implement platform specific initialization. In this case, the MachOPlatform installs a plugin that scans objects for __objc_classlist and __objc_selref sections and

Hi Bjoren, For question 1: As you mentioned, it is used to mangle to the symbol name and interning them, So ORC can find them at runtime in one of the JITDylibs. It would be helpful to know what you tried? (please attach code lines). For question 2: I guess you might be missing to link libraries that your program depend on, you can do that via setting up your dynamiclibrary search generator or