Added MesaLib-7.6

1 files changed, 898 insertions, 0 deletions

diff --git a/mesalib/src/mesa/shader/slang/slang_link.c b/mesalib/src/mesa/shader/slang/slang_link.c
new file mode 100644
index 000000000..8f2b40d5d
--- /dev/null
+++ b/mesalib/src/mesa/shader/slang/slang_link.c
@@ -0,0 +1,898 @@
+/*
+ * Mesa 3-D graphics library
+ * Version:  7.3
+ *
+ * Copyright (C) 2008  Brian Paul   All Rights Reserved.
+ * Copyright (C) 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, sublicense,
+ * 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 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 NONINFRINGEMENT.  IN NO EVENT SHALL
+ * BRIAN PAUL 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.
+ */
+
+/**
+ * \file slang_link.c
+ * GLSL linker
+ * \author Brian Paul
+ */
+
+#include "main/imports.h"
+#include "main/context.h"
+#include "main/hash.h"
+#include "main/macros.h"
+#include "shader/program.h"
+#include "shader/prog_instruction.h"
+#include "shader/prog_parameter.h"
+#include "shader/prog_print.h"
+#include "shader/prog_statevars.h"
+#include "shader/prog_uniform.h"
+#include "shader/shader_api.h"
+#include "slang_builtin.h"
+#include "slang_link.h"
+
+
+/** cast wrapper */
+static struct gl_vertex_program *
+vertex_program(struct gl_program *prog)
+{
+   assert(prog->Target == GL_VERTEX_PROGRAM_ARB);
+   return (struct gl_vertex_program *) prog;
+}
+
+
+/** cast wrapper */
+static struct gl_fragment_program *
+fragment_program(struct gl_program *prog)
+{
+   assert(prog->Target == GL_FRAGMENT_PROGRAM_ARB);
+   return (struct gl_fragment_program *) prog;
+}
+
+
+/**
+ * Record a linking error.
+ */
+static void
+link_error(struct gl_shader_program *shProg, const char *msg)
+{
+   if (shProg->InfoLog) {
+      _mesa_free(shProg->InfoLog);
+   }
+   shProg->InfoLog = _mesa_strdup(msg);
+   shProg->LinkStatus = GL_FALSE;
+}
+
+
+
+/**
+ * Check if the given bit is either set or clear in both bitfields.
+ */
+static GLboolean
+bits_agree(GLbitfield flags1, GLbitfield flags2, GLbitfield bit)
+{
+   return (flags1 & bit) == (flags2 & bit);
+}
+
+
+/**
+ * Linking varying vars involves rearranging varying vars so that the
+ * vertex program's output varyings matches the order of the fragment
+ * program's input varyings.
+ * We'll then rewrite instructions to replace PROGRAM_VARYING with either
+ * PROGRAM_INPUT or PROGRAM_OUTPUT depending on whether it's a vertex or
+ * fragment shader.
+ * This is also where we set program Input/OutputFlags to indicate
+ * which inputs are centroid-sampled, invariant, etc.
+ */
+static GLboolean
+link_varying_vars(GLcontext *ctx,
+                  struct gl_shader_program *shProg, struct gl_program *prog)
+{
+   GLuint *map, i, firstVarying, newFile;
+   GLbitfield *inOutFlags;
+
+   map = (GLuint *) malloc(prog->Varying->NumParameters * sizeof(GLuint));
+   if (!map)
+      return GL_FALSE;
+
+   /* Varying variables are treated like other vertex program outputs
+    * (and like other fragment program inputs).  The position of the
+    * first varying differs for vertex/fragment programs...
+    * Also, replace File=PROGRAM_VARYING with File=PROGRAM_INPUT/OUTPUT.
+    */
+   if (prog->Target == GL_VERTEX_PROGRAM_ARB) {
+      firstVarying = VERT_RESULT_VAR0;
+      newFile = PROGRAM_OUTPUT;
+      inOutFlags = prog->OutputFlags;
+   }
+   else {
+      assert(prog->Target == GL_FRAGMENT_PROGRAM_ARB);
+      firstVarying = FRAG_ATTRIB_VAR0;
+      newFile = PROGRAM_INPUT;
+      inOutFlags = prog->InputFlags;
+   }
+
+   for (i = 0; i < prog->Varying->NumParameters; i++) {
+      /* see if this varying is in the linked varying list */
+      const struct gl_program_parameter *var = prog->Varying->Parameters + i;
+      GLint j = _mesa_lookup_parameter_index(shProg->Varying, -1, var->Name);
+      if (j >= 0) {
+         /* varying is already in list, do some error checking */
+         const struct gl_program_parameter *v =
+            &shProg->Varying->Parameters[j];
+         if (var->Size != v->Size) {
+            link_error(shProg, "mismatched varying variable types");
+            return GL_FALSE;
+         }
+         if (!bits_agree(var->Flags, v->Flags, PROG_PARAM_BIT_CENTROID)) {
+            char msg[100];
+            _mesa_snprintf(msg, sizeof(msg),
+                           "centroid modifier mismatch for '%s'", var->Name);
+            link_error(shProg, msg);
+            return GL_FALSE;
+         }
+         if (!bits_agree(var->Flags, v->Flags, PROG_PARAM_BIT_INVARIANT)) {
+            char msg[100];
+            _mesa_snprintf(msg, sizeof(msg),
+                           "invariant modifier mismatch for '%s'", var->Name);
+            link_error(shProg, msg);
+            return GL_FALSE;
+         }
+      }
+      else {
+         /* not already in linked list */
+         j = _mesa_add_varying(shProg->Varying, var->Name, var->Size,
+                               var->Flags);
+      }
+
+      if (shProg->Varying->NumParameters > ctx->Const.MaxVarying) {
+         link_error(shProg, "Too many varying variables");
+         return GL_FALSE;
+      }
+
+      /* Map varying[i] to varying[j].
+       * Note: the loop here takes care of arrays or large (sz>4) vars.
+       */
+      {
+         GLint sz = var->Size;
+         while (sz > 0) {
+            inOutFlags[firstVarying + j] = var->Flags;
+            /*printf("Link varying from %d to %d\n", i, j);*/
+            map[i++] = j++;
+            sz -= 4;
+         }
+         i--; /* go back one */
+      }
+   }
+
+
+   /* OK, now scan the program/shader instructions looking for varying vars,
+    * replacing the old index with the new index.
+    */
+   for (i = 0; i < prog->NumInstructions; i++) {
+      struct prog_instruction *inst = prog->Instructions + i;
+      GLuint j;
+
+      if (inst->DstReg.File == PROGRAM_VARYING) {
+         inst->DstReg.File = newFile;
+         inst->DstReg.Index = map[ inst->DstReg.Index ] + firstVarying;
+      }
+
+      for (j = 0; j < 3; j++) {
+         if (inst->SrcReg[j].File == PROGRAM_VARYING) {
+            inst->SrcReg[j].File = newFile;
+            inst->SrcReg[j].Index = map[ inst->SrcReg[j].Index ] + firstVarying;
+         }
+      }
+   }
+
+   free(map);
+
+   /* these will get recomputed before linking is completed */
+   prog->InputsRead = 0x0;
+   prog->OutputsWritten = 0x0;
+
+   return GL_TRUE;
+}
+
+
+/**
+ * Build the shProg->Uniforms list.
+ * This is basically a list/index of all uniforms found in either/both of
+ * the vertex and fragment shaders.
+ *
+ * About uniforms:
+ * Each uniform has two indexes, one that points into the vertex
+ * program's parameter array and another that points into the fragment
+ * program's parameter array.  When the user changes a uniform's value
+ * we have to change the value in the vertex and/or fragment program's
+ * parameter array.
+ *
+ * This function will be called twice to set up the two uniform->parameter
+ * mappings.
+ *
+ * If a uniform is only present in the vertex program OR fragment program
+ * then the fragment/vertex parameter index, respectively, will be -1.
+ */
+static GLboolean
+link_uniform_vars(GLcontext *ctx,
+                  struct gl_shader_program *shProg,
+                  struct gl_program *prog,
+                  GLuint *numSamplers)
+{
+   GLuint samplerMap[200]; /* max number of samplers declared, not used */
+   GLuint i;
+
+   for (i = 0; i < prog->Parameters->NumParameters; i++) {
+      const struct gl_program_parameter *p = prog->Parameters->Parameters + i;
+
+      /*
+       * XXX FIX NEEDED HERE
+       * We should also be adding a uniform if p->Type == PROGRAM_STATE_VAR.
+       * For example, modelview matrix, light pos, etc.
+       * Also, we need to update the state-var name-generator code to
+       * generate GLSL-style names, like "gl_LightSource[0].position".
+       * Furthermore, we'll need to fix the state-var's size/datatype info.
+       */
+
+      if ((p->Type == PROGRAM_UNIFORM || p->Type == PROGRAM_SAMPLER)
+          && p->Used) {
+         /* add this uniform, indexing into the target's Parameters list */
+         struct gl_uniform *uniform =
+            _mesa_append_uniform(shProg->Uniforms, p->Name, prog->Target, i);
+         if (uniform)
+            uniform->Initialized = p->Initialized;
+      }
+
+      /* The samplerMap[] table we build here is used to remap/re-index
+       * sampler references by TEX instructions.
+       */
+      if (p->Type == PROGRAM_SAMPLER && p->Used) {
+         /* Allocate a new sampler index */
+         GLuint oldSampNum = (GLuint) prog->Parameters->ParameterValues[i][0];
+         GLuint newSampNum = *numSamplers;
+         if (newSampNum >= ctx->Const.MaxTextureImageUnits) {
+            char s[100];
+            _mesa_sprintf(s, "Too many texture samplers (%u, max is %u)",
+                          newSampNum, ctx->Const.MaxTextureImageUnits);
+            link_error(shProg, s);
+            return GL_FALSE;
+         }
+         /* save old->new mapping in the table */
+         if (oldSampNum < Elements(samplerMap))
+            samplerMap[oldSampNum] = newSampNum;
+         /* update parameter's sampler index */
+         prog->Parameters->ParameterValues[i][0] = (GLfloat) newSampNum;
+         (*numSamplers)++;
+      }
+   }
+
+   /* OK, now scan the program/shader instructions looking for texture
+    * instructions using sampler vars.  Replace old sampler indexes with
+    * new ones.
+    */
+   prog->SamplersUsed = 0x0;
+   for (i = 0; i < prog->NumInstructions; i++) {
+      struct prog_instruction *inst = prog->Instructions + i;
+      if (_mesa_is_tex_instruction(inst->Opcode)) {
+         /* here, inst->TexSrcUnit is really the sampler unit */
+         const GLint oldSampNum = inst->TexSrcUnit;
+
+#if 0
+         printf("====== remap sampler from %d to %d\n",
+                inst->TexSrcUnit, samplerMap[ inst->TexSrcUnit ]);
+#endif
+
+         if (oldSampNum < Elements(samplerMap)) {
+            const GLuint newSampNum = samplerMap[oldSampNum];
+            inst->TexSrcUnit = newSampNum;
+            prog->SamplerTargets[newSampNum] = inst->TexSrcTarget;
+            prog->SamplersUsed |= (1 << newSampNum);
+            if (inst->TexShadow) {
+               prog->ShadowSamplers |= (1 << newSampNum);
+            }
+         }
+      }
+   }
+
+   return GL_TRUE;
+}
+
+
+/**
+ * Resolve binding of generic vertex attributes.
+ * For example, if the vertex shader declared "attribute vec4 foobar" we'll
+ * allocate a generic vertex attribute for "foobar" and plug that value into
+ * the vertex program instructions.
+ * But if the user called glBindAttributeLocation(), those bindings will
+ * have priority.
+ */
+static GLboolean
+_slang_resolve_attributes(struct gl_shader_program *shProg,
+                          const struct gl_program *origProg,
+                          struct gl_program *linkedProg)
+{
+   GLint attribMap[MAX_VERTEX_GENERIC_ATTRIBS];
+   GLuint i, j;
+   GLbitfield usedAttributes; /* generics only, not legacy attributes */
+   GLbitfield inputsRead = 0x0;
+
+   assert(origProg != linkedProg);
+   assert(origProg->Target == GL_VERTEX_PROGRAM_ARB);
+   assert(linkedProg->Target == GL_VERTEX_PROGRAM_ARB);
+
+   if (!shProg->Attributes)
+      shProg->Attributes = _mesa_new_parameter_list();
+
+   if (linkedProg->Attributes) {
+      _mesa_free_parameter_list(linkedProg->Attributes);
+   }
+   linkedProg->Attributes = _mesa_new_parameter_list();
+
+
+   /* Build a bitmask indicating which attribute indexes have been
+    * explicitly bound by the user with glBindAttributeLocation().
+    */
+   usedAttributes = 0x0;
+   for (i = 0; i < shProg->Attributes->NumParameters; i++) {
+      GLint attr = shProg->Attributes->Parameters[i].StateIndexes[0];
+      usedAttributes |= (1 << attr);
+   }
+
+   /* If gl_Vertex is used, that actually counts against the limit
+    * on generic vertex attributes.  This avoids the ambiguity of
+    * whether glVertexAttrib4fv(0, v) sets legacy attribute 0 (vert pos)
+    * or generic attribute[0].  If gl_Vertex is used, we want the former.
+    */
+   if (origProg->InputsRead & VERT_BIT_POS) {
+      usedAttributes |= 0x1;
+   }
+
+   /* initialize the generic attribute map entries to -1 */
+   for (i = 0; i < MAX_VERTEX_GENERIC_ATTRIBS; i++) {
+      attribMap[i] = -1;
+   }
+
+   /*
+    * Scan program for generic attribute references
+    */
+   for (i = 0; i < linkedProg->NumInstructions; i++) {
+      struct prog_instruction *inst = linkedProg->Instructions + i;
+      for (j = 0; j < 3; j++) {
+         if (inst->SrcReg[j].File == PROGRAM_INPUT) {
+            inputsRead |= (1 << inst->SrcReg[j].Index);
+         }
+
+         if (inst->SrcReg[j].File == PROGRAM_INPUT &&
+             inst->SrcReg[j].Index >= VERT_ATTRIB_GENERIC0) {
+            /*
+             * OK, we've found a generic vertex attribute reference.
+             */
+            const GLint k = inst->SrcReg[j].Index - VERT_ATTRIB_GENERIC0;
+
+            GLint attr = attribMap[k];
+
+            if (attr < 0) {
+               /* Need to figure out attribute mapping now.
+                */
+               const char *name = origProg->Attributes->Parameters[k].Name;
+               const GLint size = origProg->Attributes->Parameters[k].Size;
+               const GLenum type =origProg->Attributes->Parameters[k].DataType;
+               GLint index;
+
+               /* See if there's a user-defined attribute binding for
+                * this name.
+                */
+               index = _mesa_lookup_parameter_index(shProg->Attributes,
+                                                    -1, name);
+               if (index >= 0) {
+                  /* Found a user-defined binding */
+                  attr = shProg->Attributes->Parameters[index].StateIndexes[0];
+               }
+               else {
+                  /* No user-defined binding, choose our own attribute number.
+                   * Start at 1 since generic attribute 0 always aliases
+                   * glVertex/position.
+                   */
+                  for (attr = 0; attr < MAX_VERTEX_GENERIC_ATTRIBS; attr++) {
+                     if (((1 << attr) & usedAttributes) == 0)
+                        break;
+                  }
+                  if (attr == MAX_VERTEX_GENERIC_ATTRIBS) {
+                     link_error(shProg, "Too many vertex attributes");
+                     return GL_FALSE;
+                  }
+
+                  /* mark this attribute as used */
+                  usedAttributes |= (1 << attr);
+               }
+
+               attribMap[k] = attr;
+
+               /* Save the final name->attrib binding so it can be queried
+                * with glGetAttributeLocation().
+                */
+               _mesa_add_attribute(linkedProg->Attributes, name,
+                                   size, type, attr);
+            }
+
+            assert(attr >= 0);
+
+            /* update the instruction's src reg */
+            inst->SrcReg[j].Index = VERT_ATTRIB_GENERIC0 + attr;
+         }
+      }
+   }
+
+   /* Handle pre-defined attributes here (gl_Vertex, gl_Normal, etc).
+    * When the user queries the active attributes we need to include both
+    * the user-defined attributes and the built-in ones.
+    */
+   for (i = VERT_ATTRIB_POS; i < VERT_ATTRIB_GENERIC0; i++) {
+      if (inputsRead & (1 << i)) {
+         _mesa_add_attribute(linkedProg->Attributes,
+                             _slang_vert_attrib_name(i),
+                             4, /* size in floats */
+                             _slang_vert_attrib_type(i),
+                             -1 /* attrib/input */);
+      }
+   }
+
+   return GL_TRUE;
+}
+
+
+/**
+ * Scan program instructions to update the program's NumTemporaries field.
+ * Note: this implemenation relies on the code generator allocating
+ * temps in increasing order (0, 1, 2, ... ).
+ */
+static void
+_slang_count_temporaries(struct gl_program *prog)
+{
+   GLuint i, j;
+   GLint maxIndex = -1;
+
+   for (i = 0; i < prog->NumInstructions; i++) {
+      const struct prog_instruction *inst = prog->Instructions + i;
+      const GLuint numSrc = _mesa_num_inst_src_regs(inst->Opcode);
+      for (j = 0; j < numSrc; j++) {
+         if (inst->SrcReg[j].File == PROGRAM_TEMPORARY) {
+            if (maxIndex < inst->SrcReg[j].Index)
+               maxIndex = inst->SrcReg[j].Index;
+         }
+         if (inst->DstReg.File == PROGRAM_TEMPORARY) {
+            if (maxIndex < (GLint) inst->DstReg.Index)
+               maxIndex = inst->DstReg.Index;
+         }
+      }
+   }
+
+   prog->NumTemporaries = (GLuint) (maxIndex + 1);
+}
+
+
+/**
+ * Scan program instructions to update the program's InputsRead and
+ * OutputsWritten fields.
+ */
+static void
+_slang_update_inputs_outputs(struct gl_program *prog)
+{
+   GLuint i, j;
+   GLuint maxAddrReg = 0;
+
+   prog->InputsRead = 0x0;
+   prog->OutputsWritten = 0x0;
+
+   for (i = 0; i < prog->NumInstructions; i++) {
+      const struct prog_instruction *inst = prog->Instructions + i;
+      const GLuint numSrc = _mesa_num_inst_src_regs(inst->Opcode);
+      for (j = 0; j < numSrc; j++) {
+         if (inst->SrcReg[j].File == PROGRAM_INPUT) {
+            prog->InputsRead |= 1 << inst->SrcReg[j].Index;
+         }
+         else if (inst->SrcReg[j].File == PROGRAM_ADDRESS) {
+            maxAddrReg = MAX2(maxAddrReg, (GLuint) (inst->SrcReg[j].Index + 1));
+         }
+      }
+
+      if (inst->DstReg.File == PROGRAM_OUTPUT) {
+         prog->OutputsWritten |= 1 << inst->DstReg.Index;
+         if (inst->DstReg.RelAddr) {
+            /* If the output attribute is indexed with relative addressing
+             * we know that it must be a varying or texcoord such as
+             * gl_TexCoord[i] = v;  In this case, mark all the texcoords
+             * or varying outputs as being written.  It's not an error if
+             * a vertex shader writes varying vars that aren't used by the
+             * fragment shader.  But it is an error for a fragment shader
+             * to use varyings that are not written by the vertex shader.
+             */
+            if (prog->Target == GL_VERTEX_PROGRAM_ARB) {
+               if (inst->DstReg.Index == VERT_RESULT_TEX0) {
+                  /* mark all texcoord outputs as written */
+                  const GLbitfield mask =
+                     ((1 << MAX_TEXTURE_COORD_UNITS) - 1) << VERT_RESULT_TEX0;
+                  prog->OutputsWritten |= mask;
+               }
+               else if (inst->DstReg.Index == VERT_RESULT_VAR0) {
+                  /* mark all generic varying outputs as written */
+                  const GLbitfield mask =
+                     ((1 << MAX_VARYING) - 1) << VERT_RESULT_VAR0;
+                  prog->OutputsWritten |= mask;
+               }
+            }
+         }
+      }
+      else if (inst->DstReg.File == PROGRAM_ADDRESS) {
+         maxAddrReg = MAX2(maxAddrReg, inst->DstReg.Index + 1);
+      }
+   }
+   prog->NumAddressRegs = maxAddrReg;
+}
+
+
+
+/**
+ * Remove extra #version directives from the concatenated source string.
+ * Disable the extra ones by converting first two chars to //, a comment.
+ * This is a bit of hack to work around a preprocessor bug that only
+ * allows one #version directive per source.
+ */
+static void
+remove_extra_version_directives(GLchar *source)
+{
+   GLuint verCount = 0;
+   while (1) {
+      char *ver = _mesa_strstr(source, "#version");
+      if (ver) {
+         verCount++;
+         if (verCount > 1) {
+            ver[0] = '/';
+            ver[1] = '/';
+         }
+         source += 8;
+      }
+      else {
+         break;
+      }
+   }
+}
+
+
+
+/**
+ * Return a new shader whose source code is the concatenation of
+ * all the shader sources of the given type.
+ */
+static struct gl_shader *
+concat_shaders(struct gl_shader_program *shProg, GLenum shaderType)
+{
+   struct gl_shader *newShader;
+   const struct gl_shader *firstShader = NULL;
+   GLuint shaderLengths[100];
+   GLchar *source;
+   GLuint totalLen = 0, len = 0;
+   GLuint i;
+
+   /* compute total size of new shader source code */
+   for (i = 0; i < shProg->NumShaders; i++) {
+      const struct gl_shader *shader = shProg->Shaders[i];
+      if (shader->Type == shaderType) {
+         shaderLengths[i] = _mesa_strlen(shader->Source);
+         totalLen += shaderLengths[i];
+         if (!firstShader)
+            firstShader = shader;
+      }
+   }
+
+   if (totalLen == 0)
+      return NULL;
+
+   source = (GLchar *) _mesa_malloc(totalLen + 1);
+   if (!source)
+      return NULL;
+
+   /* concatenate shaders */
+   for (i = 0; i < shProg->NumShaders; i++) {
+      const struct gl_shader *shader = shProg->Shaders[i];
+      if (shader->Type == shaderType) {
+         _mesa_memcpy(source + len, shader->Source, shaderLengths[i]);
+         len += shaderLengths[i];
+      }
+   }
+   source[len] = '\0';
+   /*
+   _mesa_printf("---NEW CONCATENATED SHADER---:\n%s\n------------\n", source);
+   */
+
+   remove_extra_version_directives(source);
+
+   newShader = CALLOC_STRUCT(gl_shader);
+   newShader->Type = shaderType;
+   newShader->Source = source;
+   newShader->Pragmas = firstShader->Pragmas;
+
+   return newShader;
+}
+
+
+/**
+ * Search the shader program's list of shaders to find the one that
+ * defines main().
+ * This will involve shader concatenation and recompilation if needed.
+ */
+static struct gl_shader *
+get_main_shader(GLcontext *ctx,
+                struct gl_shader_program *shProg, GLenum type)
+{
+   struct gl_shader *shader = NULL;
+   GLuint i;
+
+   /*
+    * Look for a shader that defines main() and has no unresolved references.
+    */
+   for (i = 0; i < shProg->NumShaders; i++) {
+      shader = shProg->Shaders[i];
+      if (shader->Type == type &&
+          shader->Main &&
+          !shader->UnresolvedRefs) {
+         /* All set! */
+         return shader;
+      }
+   }
+
+   /*
+    * There must have been unresolved references during the original
+    * compilation.  Try concatenating all the shaders of the given type
+    * and recompile that.
+    */
+   shader = concat_shaders(shProg, type);
+
+   if (shader) {
+      _slang_compile(ctx, shader);
+
+      /* Finally, check if recompiling failed */
+      if (!shader->CompileStatus ||
+          !shader->Main ||
+          shader->UnresolvedRefs) {
+         link_error(shProg, "Unresolved symbols");
+         return NULL;
+      }
+   }
+
+   return shader;
+}
+
+
+/**
+ * Shader linker.  Currently:
+ *
+ * 1. The last attached vertex shader and fragment shader are linked.
+ * 2. Varying vars in the two shaders are combined so their locations
+ *    agree between the vertex and fragment stages.  They're treated as
+ *    vertex program output attribs and as fragment program input attribs.
+ * 3. The vertex and fragment programs are cloned and modified to update
+ *    src/dst register references so they use the new, linked varying
+ *    storage locations.
+ */
+void
+_slang_link(GLcontext *ctx,
+            GLhandleARB programObj,
+            struct gl_shader_program *shProg)
+{
+   const struct gl_vertex_program *vertProg = NULL;
+   const struct gl_fragment_program *fragProg = NULL;
+   GLuint numSamplers = 0;
+   GLuint i;
+
+   _mesa_clear_shader_program_data(ctx, shProg);
+
+   /* Initialize LinkStatus to "success".  Will be cleared if error. */
+   shProg->LinkStatus = GL_TRUE;
+
+   /* check that all programs compiled successfully */
+   for (i = 0; i < shProg->NumShaders; i++) {
+      if (!shProg->Shaders[i]->CompileStatus) {
+         link_error(shProg, "linking with uncompiled shader\n");
+         return;
+      }
+   }
+
+   shProg->Uniforms = _mesa_new_uniform_list();
+   shProg->Varying = _mesa_new_parameter_list();
+
+   /*
+    * Find the vertex and fragment shaders which define main()
+    */
+   {
+      struct gl_shader *vertShader, *fragShader;
+      vertShader = get_main_shader(ctx, shProg, GL_VERTEX_SHADER);
+      fragShader = get_main_shader(ctx, shProg, GL_FRAGMENT_SHADER);
+      if (vertShader)
+         vertProg = vertex_program(vertShader->Program);
+      if (fragShader)
+         fragProg = fragment_program(fragShader->Program);
+      if (!shProg->LinkStatus)
+         return;
+   }
+
+#if FEATURE_es2_glsl
+   /* must have both a vertex and fragment program for ES2 */
+   if (!vertProg) {
+      link_error(shProg, "missing vertex shader\n");
+      return;
+   }
+   if (!fragProg) {
+      link_error(shProg, "missing fragment shader\n");
+      return;
+   }
+#endif
+
+   /*
+    * Make copies of the vertex/fragment programs now since we'll be
+    * changing src/dst registers after merging the uniforms and varying vars.
+    */
+   _mesa_reference_vertprog(ctx, &shProg->VertexProgram, NULL);
+   if (vertProg) {
+      struct gl_vertex_program *linked_vprog =
+         vertex_program(_mesa_clone_program(ctx, &vertProg->Base));
+      shProg->VertexProgram = linked_vprog; /* refcount OK */
+      /* vertex program ID not significant; just set Id for debugging purposes */
+      shProg->VertexProgram->Base.Id = shProg->Name;
+      ASSERT(shProg->VertexProgram->Base.RefCount == 1);
+   }
+
+   _mesa_reference_fragprog(ctx, &shProg->FragmentProgram, NULL);
+   if (fragProg) {
+      struct gl_fragment_program *linked_fprog = 
+         fragment_program(_mesa_clone_program(ctx, &fragProg->Base));
+      shProg->FragmentProgram = linked_fprog; /* refcount OK */
+      /* vertex program ID not significant; just set Id for debugging purposes */
+      shProg->FragmentProgram->Base.Id = shProg->Name;
+      ASSERT(shProg->FragmentProgram->Base.RefCount == 1);
+   }
+
+   /* link varying vars */
+   if (shProg->VertexProgram) {
+      if (!link_varying_vars(ctx, shProg, &shProg->VertexProgram->Base))
+         return;
+   }
+   if (shProg->FragmentProgram) {
+      if (!link_varying_vars(ctx, shProg, &shProg->FragmentProgram->Base))
+         return;
+   }
+
+   /* link uniform vars */
+   if (shProg->VertexProgram) {
+      if (!link_uniform_vars(ctx, shProg, &shProg->VertexProgram->Base,
+                             &numSamplers)) {
+         return;
+      }
+   }
+   if (shProg->FragmentProgram) {
+      if (!link_uniform_vars(ctx, shProg, &shProg->FragmentProgram->Base,
+                             &numSamplers)) {
+         return;
+      }
+   }
+
+   /*_mesa_print_uniforms(shProg->Uniforms);*/
+
+   if (shProg->VertexProgram) {
+      if (!_slang_resolve_attributes(shProg, &vertProg->Base,
+                                     &shProg->VertexProgram->Base)) {
+         return;
+      }
+   }
+
+   if (shProg->VertexProgram) {
+      _slang_update_inputs_outputs(&shProg->VertexProgram->Base);
+      _slang_count_temporaries(&shProg->VertexProgram->Base);
+      if (!(shProg->VertexProgram->Base.OutputsWritten & (1 << VERT_RESULT_HPOS))) {
+         /* the vertex program did not compute a vertex position */
+         link_error(shProg,
+                    "gl_Position was not written by vertex shader\n");
+         return;
+      }
+   }
+   if (shProg->FragmentProgram) {
+      _slang_count_temporaries(&shProg->FragmentProgram->Base);
+      _slang_update_inputs_outputs(&shProg->FragmentProgram->Base);
+   }
+
+   /* Check that all the varying vars needed by the fragment shader are
+    * actually produced by the vertex shader.
+    */
+   if (shProg->FragmentProgram) {
+      const GLbitfield varyingRead
+         = shProg->FragmentProgram->Base.InputsRead >> FRAG_ATTRIB_VAR0;
+      const GLbitfield varyingWritten = shProg->VertexProgram ?
+         shProg->VertexProgram->Base.OutputsWritten >> VERT_RESULT_VAR0 : 0x0;
+      if ((varyingRead & varyingWritten) != varyingRead) {
+         link_error(shProg,
+          "Fragment program using varying vars not written by vertex shader\n");
+         return;
+      }         
+   }
+
+   /* check that gl_FragColor and gl_FragData are not both written to */
+   if (shProg->FragmentProgram) {
+      GLbitfield outputsWritten = shProg->FragmentProgram->Base.OutputsWritten;
+      if ((outputsWritten & ((1 << FRAG_RESULT_COLOR))) &&
+          (outputsWritten >= (1 << FRAG_RESULT_DATA0))) {
+         link_error(shProg, "Fragment program cannot write both gl_FragColor"
+                    " and gl_FragData[].\n");
+         return;
+      }         
+   }
+
+
+   if (fragProg && shProg->FragmentProgram) {
+      /* Compute initial program's TexturesUsed info */
+      _mesa_update_shader_textures_used(&shProg->FragmentProgram->Base);
+
+      /* notify driver that a new fragment program has been compiled/linked */
+      ctx->Driver.ProgramStringNotify(ctx, GL_FRAGMENT_PROGRAM_ARB,
+                                      &shProg->FragmentProgram->Base);
+      if (ctx->Shader.Flags & GLSL_DUMP) {
+         _mesa_printf("Mesa pre-link fragment program:\n");
+         _mesa_print_program(&fragProg->Base);
+         _mesa_print_program_parameters(ctx, &fragProg->Base);
+
+         _mesa_printf("Mesa post-link fragment program:\n");
+         _mesa_print_program(&shProg->FragmentProgram->Base);
+         _mesa_print_program_parameters(ctx, &shProg->FragmentProgram->Base);
+      }
+   }
+
+   if (vertProg && shProg->VertexProgram) {
+      /* Compute initial program's TexturesUsed info */
+      _mesa_update_shader_textures_used(&shProg->VertexProgram->Base);
+
+      /* notify driver that a new vertex program has been compiled/linked */
+      ctx->Driver.ProgramStringNotify(ctx, GL_VERTEX_PROGRAM_ARB,
+                                      &shProg->VertexProgram->Base);
+      if (ctx->Shader.Flags & GLSL_DUMP) {
+         _mesa_printf("Mesa pre-link vertex program:\n");
+         _mesa_print_program(&vertProg->Base);
+         _mesa_print_program_parameters(ctx, &vertProg->Base);
+
+         _mesa_printf("Mesa post-link vertex program:\n");
+         _mesa_print_program(&shProg->VertexProgram->Base);
+         _mesa_print_program_parameters(ctx, &shProg->VertexProgram->Base);
+      }
+   }
+
+   /* Debug: */
+   if (0) {
+      if (shProg->VertexProgram)
+         _mesa_postprocess_program(ctx, &shProg->VertexProgram->Base);
+      if (shProg->FragmentProgram)
+         _mesa_postprocess_program(ctx, &shProg->FragmentProgram->Base);
+   }
+
+   if (ctx->Shader.Flags & GLSL_DUMP) {
+      _mesa_printf("Varying vars:\n");
+      _mesa_print_parameter_list(shProg->Varying);
+      if (shProg->InfoLog) {
+         _mesa_printf("Info Log: %s\n", shProg->InfoLog);
+      }
+   }
+
+   shProg->LinkStatus = (shProg->VertexProgram || shProg->FragmentProgram);
+}
+