llvmpipe: Pixel packing/unpacking and loop code generators.

Just a small proof of concept plus a standalone test app. Not integrated
with the rest of the driver yet.

7 files changed, 689 insertions, 1 deletions

diff --git a/src/gallium/drivers/llvmpipe/Makefile b/src/gallium/drivers/llvmpipe/Makefile
index c0c430628d..a6556c5782 100644
--- a/src/gallium/drivers/llvmpipe/Makefile
+++ b/src/gallium/drivers/llvmpipe/Makefile
@@ -7,6 +7,9 @@ C_SOURCES = \
 	lp_fs_exec.c \
 	lp_fs_sse.c \
 	lp_fs_llvm.c \
+	lp_bld_pack.c \
+	lp_bld_unpack.c \
+	lp_bld_loop.c \
 	lp_clear.c \
 	lp_flush.c \
 	lp_query.c \
diff --git a/src/gallium/drivers/llvmpipe/SConscript b/src/gallium/drivers/llvmpipe/SConscript
index f021549c44..fa3047f165 100644
--- a/src/gallium/drivers/llvmpipe/SConscript
+++ b/src/gallium/drivers/llvmpipe/SConscript
@@ -2,12 +2,17 @@ Import('*')
 
 env = env.Clone()
 
+env.ParseConfig('llvm-config --cflags --libs jit interpreter nativecodegen')
+
 llvmpipe = env.ConvenienceLibrary(
 	target = 'llvmpipe',
 	source = [
 		'lp_fs_exec.c',
 		'lp_fs_sse.c',
 		'lp_fs_llvm.c',
+		'lp_bld_pack.c',
+		'lp_bld_unpack.c',
+		'lp_bld_loop.c',
 		'lp_clear.c',
 		'lp_context.c',
 		'lp_draw_arrays.c',
@@ -43,4 +48,12 @@ llvmpipe = env.ConvenienceLibrary(
 		'lp_tile_cache.c',
 	])
 
-Export('softpipe')
\ No newline at end of file
+env['LINK'] = env['CXX']
+
+env.Program(
+    target = 'lp_bld_test',
+    source = ['lp_bld_test.c'],
+    LIBS = [llvmpipe] + auxiliaries + env['LIBS'],
+)
+
+Export('llvmpipe')
diff --git a/src/gallium/drivers/llvmpipe/lp_bld.h b/src/gallium/drivers/llvmpipe/lp_bld.h
new file mode 100644
index 0000000000..88b70d7478
--- /dev/null
+++ b/src/gallium/drivers/llvmpipe/lp_bld.h
@@ -0,0 +1,94 @@
+/**************************************************************************
+ *
+ * Copyright 2009 Vmware, Inc.
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+
+#ifndef LP_BLD_H
+#define LP_BLD_H
+
+
+/**
+ * @file
+ * LLVM IR building helpers interfaces.
+ *
+ * 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
+ * genration. See
+ * http://npcontemplation.blogspot.com/2008/06/secret-of-llvm-c-bindings.html
+ * for a standalone example.
+ */
+
+#include <llvm-c/Core.h>  
+ 
+#include "pipe/p_format.h"
+
+
+/**
+ * Unpack a pixel into its RGBA components.
+ *
+ * @param ptr value with the pointer to the packed pixel. Pointer type is
+ * irrelevant.
+ *
+ * @return RGBA in a 4 floats vector.
+ */
+LLVMValueRef
+lp_build_unpack_rgba(LLVMBuilderRef builder,
+                     enum pipe_format format, 
+                     LLVMValueRef ptr);
+
+
+/**
+ * Pack a pixel.
+ *
+ * @param rgba 4 float vector with the unpacked components.
+ */
+void 
+lp_build_pack_rgba(LLVMBuilderRef builder,
+                   enum pipe_format format,
+                   LLVMValueRef ptr,
+                   LLVMValueRef rgba);
+
+
+struct lp_build_loop_state
+{
+  LLVMBasicBlockRef block;
+  LLVMValueRef counter;
+};
+
+
+void
+lp_build_loop_begin(LLVMBuilderRef builder,
+                    LLVMValueRef start,
+                    struct lp_build_loop_state *state);
+
+
+void
+lp_build_loop_end(LLVMBuilderRef builder,
+                  LLVMValueRef end,
+                  LLVMValueRef step,
+                  struct lp_build_loop_state *state);
+
+
+#endif /* !LP_BLD_H */
diff --git a/src/gallium/drivers/llvmpipe/lp_bld_loop.c b/src/gallium/drivers/llvmpipe/lp_bld_loop.c
new file mode 100644
index 0000000000..3c0a9a1ede
--- /dev/null
+++ b/src/gallium/drivers/llvmpipe/lp_bld_loop.c
@@ -0,0 +1,91 @@
+/**************************************************************************
+ *
+ * Copyright 2009 Vmware, Inc.
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+
+#include "lp_bld.h"
+
+
+/**
+ * @file
+ * Auxiliaries to build loops.
+ *
+ * LLVM's IR doesn't represent for-loops directly. Furthermore it
+ * it requires creating code blocks, branches, phi variables, so it
+ * requires a fair amount of code.
+ *
+ * @sa http://www.llvm.org/docs/tutorial/LangImpl5.html#for
+ */
+
+
+void
+lp_build_loop_begin(LLVMBuilderRef builder,
+                    LLVMValueRef start,
+                    struct lp_build_loop_state *state)
+{
+   LLVMBasicBlockRef block = LLVMGetInsertBlock(builder);
+   LLVMValueRef function = LLVMGetBasicBlockParent(block);
+
+   state->block = LLVMAppendBasicBlock(function, "loop");
+
+   LLVMBuildBr(builder, state->block);
+
+   LLVMPositionBuilderAtEnd(builder, state->block);
+
+   state->counter = LLVMBuildPhi(builder, LLVMTypeOf(start), "");
+
+   LLVMAddIncoming(state->counter, &start, &block, 1);
+
+}
+
+
+void
+lp_build_loop_end(LLVMBuilderRef builder,
+                  LLVMValueRef end,
+                  LLVMValueRef step,
+                  struct lp_build_loop_state *state)
+{
+   LLVMBasicBlockRef block = LLVMGetInsertBlock(builder);
+   LLVMValueRef function = LLVMGetBasicBlockParent(block);
+   LLVMValueRef next;
+   LLVMValueRef cond;
+   LLVMBasicBlockRef after_block;
+
+   if (!step)
+      step = LLVMConstInt(LLVMTypeOf(end), 1, 0);
+
+   next = LLVMBuildAdd(builder, state->counter, step, "");
+
+   cond = LLVMBuildICmp(builder, LLVMIntNE, next, end, "");
+
+   after_block = LLVMAppendBasicBlock(function, "");
+
+   LLVMBuildCondBr(builder, cond, after_block, state->block);
+
+   LLVMAddIncoming(state->counter, &next, &block, 1);
+
+   LLVMPositionBuilderAtEnd(builder, after_block);
+}
+
diff --git a/src/gallium/drivers/llvmpipe/lp_bld_pack.c b/src/gallium/drivers/llvmpipe/lp_bld_pack.c
new file mode 100644
index 0000000000..7c2c7a7c76
--- /dev/null
+++ b/src/gallium/drivers/llvmpipe/lp_bld_pack.c
@@ -0,0 +1,132 @@
+/**************************************************************************
+ *
+ * Copyright 2009 Vmware, Inc.
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+
+
+#include "util/u_format.h"
+
+#include "lp_bld.h"
+
+
+void
+lp_build_pack_rgba(LLVMBuilderRef builder,
+                   enum pipe_format format,
+                   LLVMValueRef ptr,
+                   LLVMValueRef rgba)
+{
+   const struct util_format_description *desc;
+   LLVMTypeRef type;
+   LLVMValueRef packed = NULL;
+   unsigned shift = 0;
+   unsigned i, j;
+
+   desc = util_format_description(format);
+
+   assert(desc->layout == UTIL_FORMAT_LAYOUT_RGBA);
+   assert(desc->block.width == 1);
+   assert(desc->block.height == 1);
+
+   type = LLVMIntType(desc->block.bits);
+
+   LLVMValueRef swizzles[4];
+   LLVMValueRef shifted, casted, scaled, unswizzled;
+
+
+   /* Unswizzle the color components into the source vector. */
+   for (i = 0; i < 4; ++i) {
+      for (j = 0; j < 4; ++j) {
+         if (desc->swizzle[j] == i)
+            break;
+      }
+      if (j < 4)
+         swizzles[i] = LLVMConstInt(LLVMInt32Type(), j, 0);
+      else
+         swizzles[i] = LLVMGetUndef(LLVMInt32Type());
+   }
+
+   unswizzled = LLVMBuildShuffleVector(builder, rgba,
+                                       LLVMGetUndef(LLVMVectorType(LLVMFloatType(), 4)),
+                                       LLVMConstVector(swizzles, 4), "");
+
+   LLVMValueRef shifts[4];
+   LLVMValueRef scales[4];
+   bool normalized = FALSE;
+
+   for (i = 0; i < 4; ++i) {
+      unsigned bits = desc->channel[i].size;
+
+      if (desc->channel[i].type == UTIL_FORMAT_TYPE_VOID) {
+         shifts[i] = LLVMGetUndef(LLVMInt32Type());
+         scales[i] =  LLVMGetUndef(LLVMFloatType());
+      }
+      else {
+         unsigned mask = (1 << bits) - 1;
+
+         assert(desc->channel[i].type == UTIL_FORMAT_TYPE_UNSIGNED);
+         assert(bits < 32);
+
+         shifts[i] = LLVMConstInt(LLVMInt32Type(), shift, 0);
+
+         if (desc->channel[i].normalized) {
+            scales[i] = LLVMConstReal(LLVMFloatType(), mask);
+            normalized = TRUE;
+         }
+         else
+            scales[i] =  LLVMConstReal(LLVMFloatType(), 1.0);
+      }
+
+      shift += bits;
+   }
+
+   if (normalized)
+      scaled = LLVMBuildMul(builder, unswizzled, LLVMConstVector(scales, 4), "");
+   else
+      scaled = unswizzled;
+
+   casted = LLVMBuildFPToSI(builder, scaled, LLVMVectorType(LLVMInt32Type(), 4), "");
+
+   shifted = LLVMBuildShl(builder, casted, LLVMConstVector(shifts, 4), "");
+   
+   /* Bitwise or all components */
+   for (i = 0; i < 4; ++i) {
+      if (desc->channel[i].type == UTIL_FORMAT_TYPE_UNSIGNED) {
+         LLVMValueRef component = LLVMBuildExtractElement(builder, shifted, LLVMConstInt(LLVMInt32Type(), i, 0), "");
+         if (packed)
+            packed = LLVMBuildOr(builder, packed, component, "");
+         else
+            packed = component;
+      }
+   }
+
+   if (packed) {
+
+      if (desc->block.bits < 32)
+         packed = LLVMBuildTrunc(builder, packed, type, "");
+
+      LLVMBuildStore(builder, packed, LLVMBuildBitCast(builder, ptr, LLVMPointerType(type, 0), ""));
+   }
+}
+
diff --git a/src/gallium/drivers/llvmpipe/lp_bld_test.c b/src/gallium/drivers/llvmpipe/lp_bld_test.c
new file mode 100644
index 0000000000..5325b7d333
--- /dev/null
+++ b/src/gallium/drivers/llvmpipe/lp_bld_test.c
@@ -0,0 +1,199 @@
+/**************************************************************************
+ *
+ * Copyright 2009 Vmware, Inc.
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+
+
+#include <stdlib.h>
+#include <stdio.h>
+
+#include <llvm-c/Core.h>
+#include <llvm-c/Analysis.h>
+#include <llvm-c/ExecutionEngine.h>
+#include <llvm-c/Target.h>
+#include <llvm-c/Transforms/Scalar.h>
+
+#include "lp_bld.h"
+
+
+static LLVMValueRef
+add_unpack_rgba_test(LLVMModuleRef module,
+                     enum pipe_format format)
+{
+   LLVMTypeRef args[] = {
+      LLVMPointerType(LLVMInt8Type(), 0),
+      LLVMPointerType(LLVMVectorType(LLVMFloatType(), 4), 0)
+   };
+   LLVMValueRef func = LLVMAddFunction(module, "unpack", LLVMFunctionType(LLVMVoidType(), args, 2, 0));
+   LLVMSetFunctionCallConv(func, LLVMCCallConv);
+   LLVMValueRef ptr = LLVMGetParam(func, 0);
+   LLVMValueRef rgba_ptr = LLVMGetParam(func, 1);
+
+   LLVMBasicBlockRef block = LLVMAppendBasicBlock(func, "entry");
+   LLVMBuilderRef builder = LLVMCreateBuilder();
+   LLVMPositionBuilderAtEnd(builder, block);
+
+   LLVMValueRef rgba;
+
+   struct lp_build_loop_state loop;
+
+   lp_build_loop_begin(builder, LLVMConstInt(LLVMInt32Type(), 1, 0), &loop);
+
+   rgba = lp_build_unpack_rgba(builder, format, ptr);
+   LLVMBuildStore(builder, rgba, rgba_ptr);
+
+   lp_build_loop_end(builder, LLVMConstInt(LLVMInt32Type(), 4, 0), NULL, &loop);
+
+   LLVMBuildRetVoid(builder);
+
+   LLVMDisposeBuilder(builder);
+   return func;
+}
+
+
+static LLVMValueRef
+add_pack_rgba_test(LLVMModuleRef module,
+                   enum pipe_format format)
+{
+   LLVMTypeRef args[] = {
+      LLVMPointerType(LLVMInt8Type(), 0),
+      LLVMPointerType(LLVMVectorType(LLVMFloatType(), 4), 0)
+   };
+   LLVMValueRef func = LLVMAddFunction(module, "pack", LLVMFunctionType(LLVMVoidType(), args, 2, 0));
+   LLVMSetFunctionCallConv(func, LLVMCCallConv);
+   LLVMValueRef ptr = LLVMGetParam(func, 0);
+   LLVMValueRef rgba_ptr = LLVMGetParam(func, 1);
+
+   LLVMBasicBlockRef block = LLVMAppendBasicBlock(func, "entry");
+   LLVMBuilderRef builder = LLVMCreateBuilder();
+   LLVMPositionBuilderAtEnd(builder, block);
+
+   LLVMValueRef rgba;
+
+   rgba = LLVMBuildLoad(builder, rgba_ptr, "");
+
+   lp_build_pack_rgba(builder, format, ptr, rgba);
+
+   LLVMBuildRetVoid(builder);
+
+   LLVMDisposeBuilder(builder);
+   return func;
+}
+
+
+int main(int argc, char **argv)
+{
+   char *error = NULL;
+   int n;
+
+   if (argc > 1)
+      sscanf(argv[1], "%x", &n);
+   else
+      n = 0x0000f0f0;
+
+   LLVMModuleRef module = LLVMModuleCreateWithName("test");
+
+   enum pipe_format format;
+   format = PIPE_FORMAT_R5G6B5_UNORM;
+   LLVMValueRef unpack = add_unpack_rgba_test(module, format);
+   LLVMValueRef pack = add_pack_rgba_test(module, format);
+
+   LLVMVerifyModule(module, LLVMAbortProcessAction, &error);
+   LLVMDisposeMessage(error);
+
+   LLVMExecutionEngineRef engine;
+   LLVMModuleProviderRef provider = LLVMCreateModuleProviderForExistingModule(module);
+   error = NULL;
+   LLVMCreateJITCompiler(&engine, provider, 1, &error);
+   if (error) {
+      fprintf(stderr, "%s\n", error);
+      LLVMDisposeMessage(error);
+      abort();
+   }
+
+   LLVMPassManagerRef pass = LLVMCreatePassManager();
+#if 0
+   LLVMAddTargetData(LLVMGetExecutionEngineTargetData(engine), pass);
+   /* These are the passes currently listed in llvm-c/Transforms/Scalar.h,
+    * but there are more on SVN. */
+   LLVMAddConstantPropagationPass(pass);
+   LLVMAddInstructionCombiningPass(pass);
+   LLVMAddPromoteMemoryToRegisterPass(pass);
+   LLVMAddDemoteMemoryToRegisterPass(pass);
+   LLVMAddGVNPass(pass);
+   LLVMAddCFGSimplificationPass(pass);
+   LLVMRunPassManager(pass, module);
+#endif
+   LLVMDumpModule(module);
+
+   printf("Packed: %08x\n", n);
+
+   float rgba[4] = {0, 0, 0, 0};
+
+   {
+#if 1
+      typedef void (*unpack_ptr_t)(void *, float *);
+      unpack_ptr_t unpack_ptr = (unpack_ptr_t)LLVMGetPointerToGlobal(engine, unpack);
+
+      unpack_ptr(&n, rgba);
+#else
+      LLVMGenericValueRef exec_args[] = {
+         LLVMCreateGenericValueOfPointer(n),
+         LLVMCreateGenericValueOfPointer(rgba)
+      };
+      LLVMGenericValueRef exec_res = LLVMRunFunction(engine, unpack, 2, exec_args);
+#endif
+
+      printf("Unpacked: %f %f %f %f\n",
+             rgba[0],
+             rgba[1],
+             rgba[2],
+             rgba[3]);
+   }
+
+   n = 0;
+
+   {
+#if 1
+      typedef void (*pack_ptr_t)(void *, float *);
+      pack_ptr_t pack_ptr = (pack_ptr_t)LLVMGetPointerToGlobal(engine, pack);
+
+      pack_ptr(&n, rgba);
+#else
+      LLVMGenericValueRef exec_args[] = {
+         LLVMCreateGenericValueOfPointer(n),
+         LLVMCreateGenericValueOfPointer(rgba)
+      };
+      LLVMGenericValueRef exec_res = LLVMRunFunction(engine, pack, 2, exec_args);
+#endif
+
+      printf("Packed: %08x\n", n);
+   }
+
+   LLVMDisposePassManager(pass);
+   LLVMDisposeExecutionEngine(engine);
+
+   return 0;
+}
diff --git a/src/gallium/drivers/llvmpipe/lp_bld_unpack.c b/src/gallium/drivers/llvmpipe/lp_bld_unpack.c
new file mode 100644
index 0000000000..79022c68a6
--- /dev/null
+++ b/src/gallium/drivers/llvmpipe/lp_bld_unpack.c
@@ -0,0 +1,156 @@
+/**************************************************************************
+ *
+ * Copyright 2009 Vmware, Inc.
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+
+
+#include "util/u_format.h"
+
+#include "lp_bld.h"
+
+
+LLVMValueRef
+lp_build_unpack_rgba(LLVMBuilderRef builder,
+                     enum pipe_format format,
+                     LLVMValueRef ptr)
+{
+   const struct util_format_description *desc;
+   LLVMTypeRef type;
+   LLVMValueRef deferred;
+   unsigned shift = 0;
+   unsigned i;
+
+   desc = util_format_description(format);
+
+   /* FIXME: Support more formats */
+   assert(desc->layout == UTIL_FORMAT_LAYOUT_RGBA);
+   assert(desc->block.width == 1);
+   assert(desc->block.height == 1);
+   assert(desc->block.bits <= 32);
+
+   type = LLVMIntType(desc->block.bits);
+
+   deferred = LLVMBuildLoad(builder, LLVMBuildBitCast(builder, ptr, LLVMPointerType(type, 0), ""), "");
+
+   /* Do the intermediate integer computations with 32bit integers since it
+    * matches floating point size */
+   if (desc->block.bits < 32)
+      deferred = LLVMBuildZExt(builder, deferred, LLVMInt32Type(), "");
+
+   /* Broadcast the packed value to all four channels */
+   deferred = LLVMBuildInsertElement(builder,
+                                     LLVMGetUndef(LLVMVectorType(LLVMInt32Type(), 4)),
+                                     deferred,
+                                     LLVMConstNull(LLVMInt32Type()),
+                                     "");
+   deferred = LLVMBuildShuffleVector(builder,
+                                     deferred,
+                                     LLVMGetUndef(LLVMVectorType(LLVMInt32Type(), 4)),
+                                     LLVMConstNull(LLVMVectorType(LLVMInt32Type(), 4)),
+                                     "");
+
+   LLVMValueRef shifted, casted, scaled, masked, swizzled;
+   LLVMValueRef shifts[4];
+   LLVMValueRef masks[4];
+   LLVMValueRef scales[4];
+   bool normalized = FALSE;
+   int empty_channel = -1;
+
+   /* Initialize vector constants */
+   for (i = 0; i < 4; ++i) {
+      unsigned bits = desc->channel[i].size;
+
+      if (desc->channel[i].type == UTIL_FORMAT_TYPE_VOID) {
+         shifts[i] = LLVMGetUndef(LLVMInt32Type());
+         masks[i] = LLVMConstNull(LLVMInt32Type());
+         scales[i] =  LLVMConstNull(LLVMFloatType());
+         empty_channel = i;
+      }
+      else {
+         unsigned mask = (1 << bits) - 1;
+
+         assert(desc->channel[i].type == UTIL_FORMAT_TYPE_UNSIGNED);
+         assert(bits < 32);
+
+         shifts[i] = LLVMConstInt(LLVMInt32Type(), shift, 0);
+         masks[i] = LLVMConstInt(LLVMInt32Type(), mask, 0);
+
+         if (desc->channel[i].normalized) {
+            scales[i] = LLVMConstReal(LLVMFloatType(), 1.0/mask);
+            normalized = TRUE;
+         }
+         else
+            scales[i] =  LLVMConstReal(LLVMFloatType(), 1.0);
+      }
+
+      shift += bits;
+   }
+
+   shifted = LLVMBuildLShr(builder, deferred, LLVMConstVector(shifts, 4), "");
+   masked = LLVMBuildAnd(builder, shifted, LLVMConstVector(masks, 4), "");
+   // UIToFP can't be expressed in SSE2
+   casted = LLVMBuildSIToFP(builder, masked, LLVMVectorType(LLVMFloatType(), 4), "");
+
+   if (normalized)
+      scaled = LLVMBuildMul(builder, casted, LLVMConstVector(scales, 4), "");
+   else
+      scaled = casted;
+
+   LLVMValueRef swizzles[4];
+   LLVMValueRef aux[4];
+
+   for (i = 0; i < 4; ++i)
+      aux[i] = LLVMGetUndef(LLVMFloatType());
+
+   for (i = 0; i < 4; ++i) {
+      enum util_format_swizzle swizzle = desc->swizzle[i];
+
+      switch (swizzle) {
+      case UTIL_FORMAT_SWIZZLE_X:
+      case UTIL_FORMAT_SWIZZLE_Y:
+      case UTIL_FORMAT_SWIZZLE_Z:
+      case UTIL_FORMAT_SWIZZLE_W:
+         swizzles[i] = LLVMConstInt(LLVMInt32Type(), swizzle, 0);
+         break;
+      case UTIL_FORMAT_SWIZZLE_0:
+         assert(empty_channel >= 0);
+         swizzles[i] = LLVMConstInt(LLVMInt32Type(), empty_channel, 0);
+         break;
+      case UTIL_FORMAT_SWIZZLE_1:
+         swizzles[i] = LLVMConstInt(LLVMInt32Type(), 4, 0);
+         aux[0] = LLVMConstReal(LLVMFloatType(), 1.0);
+         break;
+      case UTIL_FORMAT_SWIZZLE_NONE:
+         swizzles[i] = LLVMGetUndef(LLVMFloatType());
+         assert(0);
+         break;
+      }
+   }
+
+   swizzled = LLVMBuildShuffleVector(builder, scaled, LLVMConstVector(aux, 4), LLVMConstVector(swizzles, 4), "");
+
+   return swizzled;
+}
+