On Wed, 2015-03-04 at 16:20 +0000, BogDan wrote: > On Wednesday, March 4, 2015 5:22 PM, David Malcolm <dmalc...@redhat.com> wrote: > On Wed, 2015-03-04 at 14:36 +0000, BogDan wrote: > > Hello folks, > > > > > > Probably is a little bit too early, but I'd like to ask if there is > > any chance to use gcc to produce SPIR-V [1]. > > It will be just great if we'll be able to write our shaders in e.g. > > C/C++/(any language supported by gcc) and use GCC to compile them as > > SPIR-V! > > It will be fantastic to use only one compiler collection for CPU and > > for GPU compute&graphics! > > > > Cheers, > > > > BogDan. > > [1]https://www.khronos.org/registry/spir-v/ > > I work on gcc, but in a former life I was a game developer [1], so this > piqued my interest :)
...
> SPIR-V it's an Intermediate Language binary format. First versions were > based on LLVM. SPIR-V has nothing to do with the old SPIR implementations, > but for some reason khronos decide to keep the name :) > Thishttp://www.g-truc.net/post-0714.html great article explans better > what SPIR-V is. (nods); thanks. > (B) Are you thinking about this for primarly ahead-of-time > compilation, or are you interested in just-in-time compilation to > SPIR-V? I ask since I maintain the new "libgccjit" feature in GCC 5. > One of the current assumptions in libgccjit is that host==target, but I > hope to relax that for gcc 6 so that libgccjit could e.g. generate code > for a GPU. Another gcc 6 possibility could be multi-target support for > libgccjit, so that you can populate a gcc_jit_context with code, then > have it generate machine code for both the CPU and for the GPU (mostly > just thinking aloud here). > Even though most of the people will use it for ahead-of-time compilation, > but IMHO it can be both! Another use-case that occurred to me when I was looking at the link you posted above: using gcc for optimizing SPIR-V and compiling it e.g. to CPU code. As of gcc 5, libgccjit can be hooked up to a pre-existing language frontend, with the gcc backend emitting machine code for the CPU, assuming that the frontend is license-compatible with libgccjit's GPLv3-or-later. See this example, which uses libgccjit to build a compiler for brainf**k: https://gcc.gnu.org/onlinedocs/jit/intro/tutorial05.html So if there's a SPIR-V loader library that's license-compatible, you could write code to inject SPIR-V into libgccjit, and call gcc_jit_context_compile_to_file on it to optimize it and turn it into machine code.
Johann Sorel has written a SPIR-v binary reader and writer with a compatible license (public domain). https://bitbucket.org/Eclesia/unlicense/src/tip/compiler/compiler-spir/src/main/java/un/language/spir/?at=default To quote Johann Sorel: "it's public domain, copy what you need ;)" https://jogamp.org/bugzilla/show_bug.cgi?id=1140#c2 These SPIR-v classes is to my knowledge the first public SPIR-v reader and writer with a free software compatible license. You can use the GCC GCJ project and Johann Sorel's Java classes that gives you all SPIR-v spec constants in machine readable form and a SPIR-v binary parser and writer as a foundation to create your SPIR-v compiler & assembler. Cheers Xerxes
