similar to: Thoughts on the LLVM linker

Hi llvmers, As you may know, work has been progressing on the experimental WebAssembly backend in llvm. However, there is currently not a good linking story. Most the of existing linking strategies (i.e. those in the emscripten toolchain) involve bitcode linking and whole program compilation at link time. To improve this situation I've been working on adding a wasm backend for lld. My

Can you link to docs about the wasm object format? (both relocatable and executable) Also, traditional object file linkers are primarily concerned with concatenating binary blobs with small amount of patching of said binary blobs based on computed virtual (memory) addresses. Or perhaps to put it another way, what traditional object file linkers do is construct program images meant to be mapped

Hi Sam, First, I want to know the symbol resolution semantics. I can imagine that that is set in stone yet, but just that you guys are still discussing what would be the best semantics or file format for the linkable wasm object file. I think by knowing more about the format and semantics, we can give you guys valuable feedback, as we've been actively working on the linker for a few years

On Mon, Jul 10, 2017 at 4:13 PM, Rui Ueyama via llvm-dev <llvm-dev at lists.llvm.org> wrote: > Sorry for the belated response. I was on vacation last week. A couple of > thoughts on this patch and the story of webassembly linking. And I'm about to be on (mostly) vacation for next 3 weeks :) > > - This patch adds a wasm support as yet another major architecture besides >

Using LLVM v5, my Cone compiler (https://github.com/jondgoodwin/cone) automatically directly generated all functions as named and exported for both wasm text and binary files (not using clang/lld etc, but using the API). Upgrading to LLVM v7, generated wasm object files now fail, exhibiting markedly different behavior, behavior that varies between the text and binary files. For example, the

Sean Silva <chisophugis at gmail.com> writes: > On Mon, Jul 3, 2017 at 11:12 AM, Rafael Avila de Espindola < > rafael.espindola at gmail.com> wrote: > >> Sam Clegg via llvm-dev <llvm-dev at lists.llvm.org> writes: >> >> >> Can you elaborate on semantically what the linker is actually doing for >> >> wasm? >> > >> >

Dan Gohman <sunfish at mozilla.com> writes: >> Sorry, I meant why that didn't work with ELF (or what else didn't). >> > > The standard executable WebAssembly format does not use ELF, for numerous > reasons, most visibly that ELF is designed for sparse decoding -- headers > contain offsets to arbitrary points in the file, while WebAssembly's format > is

wasm-ld is currently unable to link a shared wasm library (generated with `wasm-ld --shared`) with .o files and produce a working executable. I'm curious if there's a fundamental reason for this, or is this simply something that wasn't needed and could be implemented if needed. I think this could be done by - Resolving "GOT.mem" and "GOT.func" imports and

Sam Clegg via llvm-dev <llvm-dev at lists.llvm.org> writes: >> Can you elaborate on semantically what the linker is actually doing for >> wasm? > > You are correct that the wasm linker does have more work to do than a > traditional linker. There are more sections that the linker will need > to re-construct fully. This is because there is more high level >

Apologies if there is a better forum for these questions. Please redirect me if so. I’ve been using the clang/wasm-ld tools to experiment with some basic examples, and there’s a couple things I’m wrestling with. 1) How to denote a function as the “start” function (https://webassembly.github.io/spec/core/binary/modules.html#start-section) 2) How to avoid the defaulted __heap_base global. I’ve

Okay, so where should I send questions for WebAssembly? Is it this mailing list or a different one? I want to ask about how to compile WebAssembly modules with Clang directly, without Emscripten, for situations like what I have currently where I have a problem with generating WebAssembly and/or JavaScript glue code (I have a problem with the gen_struct_info stuff; I asked on the Emscripten

Hi again, It is probably me doing something wrong, but I have attached a trimmed down sample that shows the issue and the output that Clang 8.0.0 makes (using the binary release from llvm.org). I invoke clang as follows: clang -S -O3 -o Evergrowing.s -Wall Evergrowing.ll I tried using -O1, -O2, and -O3, but all where the same. Please notice that I renamed 'main()' to

Hello, The table generated by lld (Wasm target) have a max size. So this make impossible to add some others functions in the table . As for the moment only one Table is available in WAsm this is the only way to add function in a dynamic way. Having a none static size of the table is useful for a kind dynamic loader/inker at run-time: by adding some exported functions coming from another

Hi Sam, Thanks for your answer! Sorry I didn't really know how to process, but this issue block me to make some legacy C code works without having some glue with a bit static lib ;( (The change have really low risk) The changes I used locally to make dlopen/dlclose et dlsym mechanism works :) : Index: wasm/Writer.cpp =================================================================== ---

Hi guys, I am doing a hobby compiler using LLVM. I have a rather peculiar problem with the 'select' instruction, as far as I can see. Given this code: ************************************************ ; Run-time Library Definitions %Exception = type { i8 } define private %Exception* @Start(i1* %$result) #0 { prologue: store i1 true, i1* %$result br label %epilogue epilogue:

Hi All, WebAssembly has been around for a while now, it's still being actively worked on and used. I think it's long past time we make it a normal target so that it gets tested on a regular basis. (Most recent random breakage is https://reviews.llvm.org/rL342576 which fails make check with web assembly enabled). Any objections? I'll probably do this next week unless someone raises a

Hello. Excuse me. Why CMakeLists.txt from llvm-3.9.1.src does not contain WebAssembly target? So, it is like set(LLVM_ALL_TARGETS AArch64 AMDGPU ARM BPF Hexagon Mips MSP430 NVPTX PowerPC Sparc SystemZ X86 XCore ) but not like set(LLVM_ALL_TARGETS AArch64 AMDGPU ARM BPF Hexagon Mips MSP430 NVPTX PowerPC Sparc SystemZ Webassembly X86

David, That's right, WebAssembly does not have a way to conditionally use a feature or even do runtime feature testing right now. It's on our roadmap of things to design and standardize, but it is still a long way off. > Another direction would be to require the features to be specified consistently for all components of the build, I guess - if that's the net effect anyway. Would

Thanks for the quick reply. I had a feeling that it was due to missing Windows support in clang++ and LLVM. """ This is due to clang not understanding force_inline. These functions are defined in a header included from Windows.h, so it ends up getting a definition everywhere it is included. """ How much work would it take to add support for force_inline? Are there

Hi, Sorry if you've seen this message before on llvm.discourse.group or elsewhere -- I've been trying to get to the bottom of this for a while now and asked about this in a few different platforms before. I'm currently trying to debug a bug in a LLVM-generated Wasm code. The bug could be in the code that generates LLVM (rustc) or in the LLVM, I'm not sure yet. LLVM IR and Wasm