| LLVMPIPE -- a fork of softpipe that employs LLVM for code generation. |
| |
| |
| Status |
| ====== |
| |
| Done so far is: |
| |
| - the whole fragment pipeline is code generated in a single function |
| |
| - input interpolation |
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| - depth testing |
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| - texture sampling (not all state/formats are supported) |
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| - fragment shader TGSI translation |
| - same level of support as the TGSI SSE2 exec machine, with the exception |
| we don't fallback to TGSI interpretation when an unsupported opcode is |
| found, but just ignore it |
| - done in SoA layout |
| - input interpolation also code generated |
| |
| - alpha testing |
| |
| - blend (including logic ops) |
| - both in SoA and AoS layouts, but only the former used for now |
| |
| - code is generic |
| - intermediates can be vectors of floats, ubytes, fixed point, etc, and of |
| any width and length |
| - not all operations are implemented for these types yet though |
| |
| Most mesa/progs/demos/* work. |
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| To do (probably by this order): |
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| - code generate stipple and stencil testing |
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| - translate the remaining bits of texture sampling state |
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| - translate TGSI control flow instructions, and all other remaining opcodes |
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| - integrate with the draw module for VS code generation |
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| - code generate the triangle setup and rasterization |
| |
| |
| Requirements |
| ============ |
| |
| - Linux |
| |
| - udis86, http://udis86.sourceforge.net/ . Use my repository, which decodes |
| opcodes not yet supported by upstream. |
| |
| git clone git://people.freedesktop.org/~jrfonseca/udis86 |
| cd udis86 |
| ./configure --with-pic |
| make |
| sudo make install |
| |
| - LLVM 2.5. On Debian based distributions do: |
| |
| aptitude install llvm-dev |
| |
| There is a typo in one of the llvm-dev 2.5 headers, that causes compilation |
| errors in the debug build: |
| |
| --- /usr/include/llvm-c/Core.h.orig 2009-08-10 15:38:54.000000000 +0100 |
| +++ /usr/include/llvm-c/Core.h 2009-08-10 15:38:25.000000000 +0100 |
| @@ -831,7 +831,7 @@ |
| template<typename T> |
| inline T **unwrap(LLVMValueRef *Vals, unsigned Length) { |
| #if DEBUG |
| - for (LLVMValueRef *I = Vals, E = Vals + Length; I != E; ++I) |
| + for (LLVMValueRef *I = Vals, *E = Vals + Length; I != E; ++I) |
| cast<T>(*I); |
| #endif |
| return reinterpret_cast<T**>(Vals); |
| |
| - A x86 or amd64 processor with support for sse2, sse3, and sse4.1 SIMD |
| instructions. This is necessary because we emit several SSE intrinsics for |
| convenience. See /proc/cpuinfo to know what your CPU supports. |
| |
| - scons |
| |
| |
| Building |
| ======== |
| |
| To build everything invoke scons as: |
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| scons debug=yes statetrackers=mesa drivers=llvmpipe winsys=xlib dri=false -k |
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| Alternatively, you can build it with GNU make, if you prefer, by invoking it as |
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| make linux-llvm |
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| but the rest of these instructions assume that scons is used. |
| |
| |
| Using |
| ===== |
| |
| Building will create a drop-in alternative for libGL.so. To use it set the |
| environment variables: |
| |
| export LD_LIBRARY_PATH=$PWD/build/linux-x86_64-debug/lib:$LD_LIBRARY_PATH |
| |
| or |
| |
| export LD_LIBRARY_PATH=$PWD/build/linux-x86-debug/lib:$LD_LIBRARY_PATH |
| |
| For performance evaluation pass debug=no to scons, and use the corresponding |
| lib directory without the "-debug" suffix. |
| |
| |
| Unit testing |
| ============ |
| |
| Building will also create several unit tests in |
| build/linux-???-debug/gallium/drivers/llvmpipe: |
| |
| - lp_test_blend: blending |
| - lp_test_conv: SIMD vector conversion |
| - lp_test_format: pixel unpacking/packing |
| |
| Some of this tests can output results and benchmarks to a tab-separated-file |
| for posterior analysis, e.g.: |
| |
| build/linux-x86_64-debug/gallium/drivers/llvmpipe/lp_test_blend -o blend.tsv |
| |
| |
| Development Notes |
| ================= |
| |
| - When looking to this code by the first time start in lp_state_fs.c, and |
| then skim through the lp_bld_* functions called in there, and the comments |
| at the top of the lp_bld_*.c functions. |
| |
| - All lp_bld_*.[ch] are isolated from the rest of the driver, and could/may be |
| put in a stand-alone Gallium state -> LLVM IR translation module. |
| |
| - We use LLVM-C bindings for now. They are not documented, but follow the C++ |
| interfaces very closely, and appear to be complete enough for code |
| generation. See |
| http://npcontemplation.blogspot.com/2008/06/secret-of-llvm-c-bindings.html |
| for a stand-alone example. |