mesa: allow variable indexing into the predefined uniform variable arrays

This allows code such as "vec4 a = gl_LightSource[i].ambient;" to work.

When a built-in uniform array is indexed with a variable index we need to
"unroll" the whole array into the parameter list (aka constant buffer) because
we don't know which elements may be accessed at compile-time.  In the case of
the gl_LightSource array of size [8], we emit 64 state references into the
parameter array (8 elements times 8 vec4s per gl_LightSourceParameters
struct).

Previously, we only allowed constant-indexed references to uniform arrays
(such as gl_LightSource[2].position) which resulted in a single state reference
being added to the parameter array, not 64.  We still optimize this case.

Users should be aware that using "gl_LightSource[i].ambient" in their shaders
is a bit expensive since state validation will involve updating all 64
light source entries in the parameter list.

(cherry picked from commit c6537ac8b8130cf2271c8d1e51137a575073c762)

5 files changed, 376 insertions, 91 deletions

diff --git a/src/mesa/shader/slang/library/slang_common_builtin.gc b/src/mesa/shader/slang/library/slang_common_builtin.gc
index a051c53eea..3e03b101b8 100644
--- a/src/mesa/shader/slang/library/slang_common_builtin.gc
+++ b/src/mesa/shader/slang/library/slang_common_builtin.gc
@@ -1,8 +1,9 @@
 /*
  * Mesa 3-D graphics library
- * Version:  6.5
+ * Version:  7.3
  *
  * Copyright (C) 2006  Brian Paul   All Rights Reserved.
+ * Copyright (C) 2008  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"),
@@ -98,6 +99,9 @@ struct gl_MaterialParameters {
 uniform gl_MaterialParameters gl_FrontMaterial;
 uniform gl_MaterialParameters gl_BackMaterial;
 
+/* NOTE: the order of these fields is significant!
+ * See the definition of the lighting state vars such as STATE_SPOT_DIRECTION.
+ */
 struct gl_LightSourceParameters {
     vec4 ambient;
     vec4 diffuse;
@@ -105,12 +109,14 @@ struct gl_LightSourceParameters {
     vec4 position;
     vec4 halfVector;
     vec3 spotDirection;
-    float spotExponent;
-    float spotCutoff;
     float spotCosCutoff;
+
     float constantAttenuation;
     float linearAttenuation;
     float quadraticAttenuation;
+    float spotExponent;
+
+    float spotCutoff;
 };
 
 uniform gl_LightSourceParameters gl_LightSource[gl_MaxLights];
diff --git a/src/mesa/shader/slang/library/slang_common_builtin_gc.h b/src/mesa/shader/slang/library/slang_common_builtin_gc.h
index 4663201081..759bf247d8 100644
--- a/src/mesa/shader/slang/library/slang_common_builtin_gc.h
+++ b/src/mesa/shader/slang/library/slang_common_builtin_gc.h
@@ -66,58 +66,58 @@
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diff --git a/src/mesa/shader/slang/slang_builtin.c b/src/mesa/shader/slang/slang_builtin.c
index db00c54b8a..c0f4c79e13 100644
--- a/src/mesa/shader/slang/slang_builtin.c
+++ b/src/mesa/shader/slang/slang_builtin.c
@@ -1,8 +1,9 @@
 /*
  * Mesa 3-D graphics library
- * Version:  6.5.3
+ * Version:  7.3
  *
  * Copyright (C) 2005-2007  Brian Paul   All Rights Reserved.
+ * Copyright (C) 2008  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"),
@@ -39,6 +40,10 @@
 #include "shader/slang/slang_builtin.h"
 
 
+/** special state token (see below) */
+#define STATE_ARRAY ((gl_state_index) 0xfffff)
+
+
 /**
  * Lookup GL state given a variable name, 0, 1 or 2 indexes and a field.
  * Allocate room for the state in the given param list and return position
@@ -132,6 +137,8 @@ lookup_statevar(const char *var, GLint index1, GLint index2, const char *field,
       }
    }
    else if (strcmp(var, "gl_ClipPlane") == 0) {
+      if (index1 < 0)
+         return -1;
       tokens[0] = STATE_CLIPPLANE;
       tokens[1] = index1;
    }
@@ -196,8 +203,12 @@ lookup_statevar(const char *var, GLint index1, GLint index2, const char *field,
       }
    }
    else if (strcmp(var, "gl_LightSource") == 0) {
+      if (!field || index1 < 0)
+         return -1;
+
       tokens[0] = STATE_LIGHT;
       tokens[1] = index1;
+
       if (strcmp(field, "ambient") == 0) {
          tokens[2] = STATE_AMBIENT;
       }
@@ -272,6 +283,9 @@ lookup_statevar(const char *var, GLint index1, GLint index2, const char *field,
    }
    else if (strcmp(var, "gl_FrontLightProduct") == 0 ||
             strcmp(var, "gl_BackLightProduct") == 0) {
+      if (index1 < 0 || !field)
+         return -1;
+
       tokens[0] = STATE_LIGHTPROD;
       tokens[1] = index1; /* light number */
       if (strcmp(var, "gl_FrontLightProduct") == 0) {
@@ -294,45 +308,63 @@ lookup_statevar(const char *var, GLint index1, GLint index2, const char *field,
       }
    }
    else if (strcmp(var, "gl_TextureEnvColor") == 0) {
+      if (index1 < 0)
+         return -1;
       tokens[0] = STATE_TEXENV_COLOR;
       tokens[1] = index1;
    }
    else if (strcmp(var, "gl_EyePlaneS") == 0) {
+      if (index1 < 0)
+         return -1;
       tokens[0] = STATE_TEXGEN;
       tokens[1] = index1; /* tex unit */
       tokens[2] = STATE_TEXGEN_EYE_S;
    }
    else if (strcmp(var, "gl_EyePlaneT") == 0) {
+      if (index1 < 0)
+         return -1;
       tokens[0] = STATE_TEXGEN;
       tokens[1] = index1; /* tex unit */
       tokens[2] = STATE_TEXGEN_EYE_T;
    }
    else if (strcmp(var, "gl_EyePlaneR") == 0) {
+      if (index1 < 0)
+         return -1;
       tokens[0] = STATE_TEXGEN;
       tokens[1] = index1; /* tex unit */
       tokens[2] = STATE_TEXGEN_EYE_R;
    }
    else if (strcmp(var, "gl_EyePlaneQ") == 0) {
+      if (index1 < 0)
+         return -1;
       tokens[0] = STATE_TEXGEN;
       tokens[1] = index1; /* tex unit */
       tokens[2] = STATE_TEXGEN_EYE_Q;
    }
    else if (strcmp(var, "gl_ObjectPlaneS") == 0) {
+      if (index1 < 0)
+         return -1;
       tokens[0] = STATE_TEXGEN;
       tokens[1] = index1; /* tex unit */
       tokens[2] = STATE_TEXGEN_OBJECT_S;
    }
    else if (strcmp(var, "gl_ObjectPlaneT") == 0) {
+      if (index1 < 0)
+         return -1;
       tokens[0] = STATE_TEXGEN;
       tokens[1] = index1; /* tex unit */
       tokens[2] = STATE_TEXGEN_OBJECT_T;
    }
    else if (strcmp(var, "gl_ObjectPlaneR") == 0) {
+      if (index1 < 0)
+         return -1;
       tokens[0] = STATE_TEXGEN;
       tokens[1] = index1; /* tex unit */
       tokens[2] = STATE_TEXGEN_OBJECT_R;
    }
    else if (strcmp(var, "gl_ObjectPlaneQ") == 0) {
+      if (index1 < 0)
+         return -1;
       tokens[0] = STATE_TEXGEN;
       tokens[1] = index1; /* tex unit */
       tokens[2] = STATE_TEXGEN_OBJECT_Q;
@@ -386,13 +418,222 @@ lookup_statevar(const char *var, GLint index1, GLint index2, const char *field,
 }
 
 
+
+/**
+ * Given a variable name and datatype, emit uniform/constant buffer
+ * entries which will store that state variable.
+ * For example, if name="gl_LightSource" we'll emit 64 state variable
+ * vectors/references and return position where that data starts.  This will
+ * allow run-time array indexing into the light source array.
+ *
+ * Note that this is a recursive function.
+ *
+ * \return -1 if error, else index of start of data in the program parameter list
+ */
+static GLint
+emit_statevars(const char *name, int array_len,
+               const slang_type_specifier *type,
+               gl_state_index tokens[STATE_LENGTH],
+               struct gl_program_parameter_list *paramList)
+{
+   if (type->type == SLANG_SPEC_ARRAY) {
+      GLint i, pos;
+      assert(array_len > 0);
+      if (strcmp(name, "gl_ClipPlane") == 0) {
+         tokens[0] = STATE_CLIPPLANE;
+      }
+      else if (strcmp(name, "gl_LightSource") == 0) {
+         tokens[0] = STATE_LIGHT;
+      }
+      else if (strcmp(name, "gl_FrontLightProduct") == 0) {
+         tokens[0] = STATE_LIGHTPROD;
+         tokens[2] = 0; /* front */
+      }
+      else if (strcmp(name, "gl_BackLightProduct") == 0) {
+         tokens[0] = STATE_LIGHTPROD;
+         tokens[2] = 1; /* back */
+      }
+      else if (strcmp(name, "gl_TextureEnvColor") == 0) {
+         tokens[0] = STATE_TEXENV_COLOR;
+      }
+      else if (strcmp(name, "gl_EyePlaneS") == 0) {
+         tokens[0] = STATE_TEXGEN_EYE_S;
+      }
+      else if (strcmp(name, "gl_EyePlaneT") == 0) {
+         tokens[0] = STATE_TEXGEN_EYE_T;
+      }
+      else if (strcmp(name, "gl_EyePlaneR") == 0) {
+         tokens[0] = STATE_TEXGEN_EYE_R;
+      }
+      else if (strcmp(name, "gl_EyePlaneQ") == 0) {
+         tokens[0] = STATE_TEXGEN_EYE_Q;
+      }
+      else if (strcmp(name, "gl_ObjectPlaneS") == 0) {
+         tokens[0] = STATE_TEXGEN_OBJECT_S;
+      }
+      else if (strcmp(name, "gl_ObjectPlaneT") == 0) {
+         tokens[0] = STATE_TEXGEN_OBJECT_T;
+      }
+      else if (strcmp(name, "gl_ObjectPlaneR") == 0) {
+         tokens[0] = STATE_TEXGEN_OBJECT_R;
+      }
+      else if (strcmp(name, "gl_ObjectPlaneQ") == 0) {
+         tokens[0] = STATE_TEXGEN_OBJECT_Q;
+      }
+      else {
+         return -1; /* invalid array name */
+      }
+      for (i = 0; i < array_len; i++) {
+         GLint p;
+         tokens[1] = i;
+         p = emit_statevars(NULL, 0, type->_array, tokens, paramList);
+         if (i == 0)
+            pos = p;
+      }
+      return pos;
+   }
+   else if (type->type == SLANG_SPEC_STRUCT) {
+      const slang_variable_scope *fields = type->_struct->fields;
+      GLuint i, pos;
+      for (i = 0; i < fields->num_variables; i++) {
+         const slang_variable *var = fields->variables[i];
+         GLint p = emit_statevars(var->a_name, 0, &var->type.specifier,
+                                  tokens, paramList);
+         if (i == 0)
+            pos = p;
+      }
+      return pos;
+   }
+   else {
+      GLint pos;
+      assert(type->type == SLANG_SPEC_VEC4 ||
+             type->type == SLANG_SPEC_VEC3 ||
+             type->type == SLANG_SPEC_VEC2 ||
+             type->type == SLANG_SPEC_FLOAT ||
+             type->type == SLANG_SPEC_IVEC4 ||
+             type->type == SLANG_SPEC_IVEC3 ||
+             type->type == SLANG_SPEC_IVEC2 ||
+             type->type == SLANG_SPEC_INT);
+      if (name) {
+         GLint t;
+
+         if (tokens[0] == STATE_LIGHT)
+            t = 2;
+         else if (tokens[0] == STATE_LIGHTPROD)
+            t = 3;
+         else
+            return -1; /* invalid array name */
+
+         if (strcmp(name, "ambient") == 0) {
+            tokens[t] = STATE_AMBIENT;
+         }
+         else if (strcmp(name, "diffuse") == 0) {
+            tokens[t] = STATE_DIFFUSE;
+         }
+         else if (strcmp(name, "specular") == 0) {
+            tokens[t] = STATE_SPECULAR;
+         }
+         else if (strcmp(name, "position") == 0) {
+            tokens[t] = STATE_POSITION;
+         }
+         else if (strcmp(name, "halfVector") == 0) {
+            tokens[t] = STATE_HALF_VECTOR;
+         }
+         else if (strcmp(name, "spotDirection") == 0) {
+            tokens[t] = STATE_SPOT_DIRECTION; /* xyz components */
+         }
+         else if (strcmp(name, "spotCosCutoff") == 0) {
+            tokens[t] = STATE_SPOT_DIRECTION; /* w component */
+         }
+
+         else if (strcmp(name, "constantAttenuation") == 0) {
+            tokens[t] = STATE_ATTENUATION; /* x component */
+         }
+         else if (strcmp(name, "linearAttenuation") == 0) {
+            tokens[t] = STATE_ATTENUATION; /* y component */
+         }
+         else if (strcmp(name, "quadraticAttenuation") == 0) {
+            tokens[t] = STATE_ATTENUATION; /* z component */
+         }
+         else if (strcmp(name, "spotExponent") == 0) {
+            tokens[t] = STATE_ATTENUATION; /* w = spot exponent */
+         }
+
+         else if (strcmp(name, "spotCutoff") == 0) {
+            tokens[t] = STATE_SPOT_CUTOFF; /* x component */
+         }
+
+         else {
+            return -1; /* invalid field name */
+         }
+      }
+
+      pos = _mesa_add_state_reference(paramList, tokens);
+      return pos;
+   }
+
+   return 1;
+}
+
+
+/**
+ * Unroll the named built-in uniform variable into a sequence of state
+ * vars in the given parameter list.
+ */
+static GLint
+alloc_state_var_array(const slang_variable *var,
+                      struct gl_program_parameter_list *paramList)
+{
+   gl_state_index tokens[STATE_LENGTH];
+   GLuint i;
+   GLint pos;
+
+   /* Initialize the state tokens array.  This is very important.
+    * When we call _mesa_add_state_reference() it'll searches the parameter
+    * list to see if the given statevar token sequence is already present.
+    * This is normally a good thing since it prevents redundant values in the
+    * constant buffer.
+    *
+    * But when we're building arrays of state this can be bad.  For example,
+    * consider this fragment of GLSL code:
+    *   foo = gl_LightSource[3].diffuse;
+    *   ...
+    *   bar = gl_LightSource[i].diffuse;
+    *
+    * When we unroll the gl_LightSource array (for "bar") we want to re-emit
+    * gl_LightSource[3].diffuse and not re-use the first instance (from "foo")
+    * since that would upset the array layout.  We handle this situation by
+    * setting the last token in the state var token array to the special
+    * value STATE_ARRAY.
+    * This token will only be set for array state.  We can hijack the last
+    * element in the array for this since it's never used for light, clipplane
+    * or texture env array state.
+    */
+   for (i = 0; i < STATE_LENGTH; i++)
+      tokens[i] = 0;
+   tokens[STATE_LENGTH - 1] = STATE_ARRAY;
+
+   pos = emit_statevars(var->a_name, var->array_len, &var->type.specifier,
+                        tokens, paramList);
+
+   return pos;
+}
+
+
+
 /**
  * Allocate storage for a pre-defined uniform (a GL state variable).
  * As a memory-saving optimization, we try to only allocate storage for
  * state vars that are actually used.
- * For example, the "gl_LightSource" uniform is huge.  If we only use
- * a handful of gl_LightSource fields, we don't want to allocate storage
- * for all of gl_LightSource.
+ *
+ * Arrays such as gl_LightSource are handled specially.  For an expression
+ * like "gl_LightSource[2].diffuse", we can allocate a single uniform/constant
+ * slot and return the index.  In this case, we return direct=TRUE.
+ *
+ * Buf for something like "gl_LightSource[i].diffuse" we don't know the value
+ * of 'i' at compile time so we need to "unroll" the gl_LightSource array
+ * into a consecutive sequence of uniform/constant slots so it can be indexed
+ * at runtime.  In this case, we return direct=FALSE.
  *
  * Currently, all pre-defined uniforms are in one of these forms:
  *   var
@@ -401,52 +642,62 @@ lookup_statevar(const char *var, GLint index1, GLint index2, const char *field,
  *   var[i].field
  *   var[i][j]
  *
- * \return -1 upon error, else position in paramList of the state var/data
+ * \return -1 upon error, else position in paramList of the state variable/data
  */
 GLint
 _slang_alloc_statevar(slang_ir_node *n,
-                      struct gl_program_parameter_list *paramList)
+                      struct gl_program_parameter_list *paramList,
+                      GLboolean *direct)
 {
    slang_ir_node *n0 = n;
-   const char *field = NULL, *var;
-   GLint index1 = -1, index2 = -1, pos;
+   const char *field = NULL;
+   GLint index1 = -1, index2 = -1;
    GLuint swizzle;
 
+   *direct = GL_TRUE;
+
    if (n->Opcode == IR_FIELD) {
       field = n->Field;
       n = n->Children[0];
    }
 
    if (n->Opcode == IR_ELEMENT) {
-      /* XXX can only handle constant indexes for now */
       if (n->Children[1]->Opcode == IR_FLOAT) {
          index1 = (GLint) n->Children[1]->Value[0];
-         n = n->Children[0];
       }
       else {
-         return -1;
+         *direct = GL_FALSE;
       }
+      n = n->Children[0];
    }
 
    if (n->Opcode == IR_ELEMENT) {
       /* XXX can only handle constant indexes for now */
-      assert(n->Children[1]->Opcode == IR_FLOAT);
-      index2 = (GLint) n->Children[1]->Value[0];
+      if (n->Children[1]->Opcode == IR_FLOAT) {
+         index2 = (GLint) n->Children[1]->Value[0];
+      }
+      else {
+         *direct = GL_FALSE;
+      }
       n = n->Children[0];
    }
 
    assert(n->Opcode == IR_VAR);
-   var = (char *) n->Var->a_name;
 
-   pos = lookup_statevar(var, index1, index2, field, &swizzle, paramList);
-   assert(pos >= 0);
-   if (pos >= 0) {
-      /* newly resolved storage for the statevar/constant/uniform */
-      n0->Store->File = PROGRAM_STATE_VAR;
-      n0->Store->Index = pos;
-      n0->Store->Swizzle = swizzle;
-      n0->Store->Parent = NULL;
+   if (*direct) {
+      const char *var = (const char *) n->Var->a_name;
+      GLint pos =
+         lookup_statevar(var, index1, index2, field, &swizzle, paramList);
+      if (pos >= 0) {
+         /* newly resolved storage for the statevar/constant/uniform */
+         n0->Store->File = PROGRAM_STATE_VAR;
+         n0->Store->Index = pos;
+         n0->Store->Swizzle = swizzle;
+         n0->Store->Parent = NULL;
+         return pos;
+      }
    }
-   return pos;
-}
 
+   *direct = GL_FALSE;
+   return alloc_state_var_array(n->Var, paramList);
+}
diff --git a/src/mesa/shader/slang/slang_builtin.h b/src/mesa/shader/slang/slang_builtin.h
index 58629f4f7f..7f6fe80fcc 100644
--- a/src/mesa/shader/slang/slang_builtin.h
+++ b/src/mesa/shader/slang/slang_builtin.h
@@ -33,7 +33,8 @@
 
 extern GLint
 _slang_alloc_statevar(slang_ir_node *n,
-                      struct gl_program_parameter_list *paramList);
+                      struct gl_program_parameter_list *paramList,
+                      GLboolean *direct);
 
 
 #endif /* SLANG_BUILTIN_H */
diff --git a/src/mesa/shader/slang/slang_emit.c b/src/mesa/shader/slang/slang_emit.c
index 4eaa7fae5a..1e9b4c1254 100644
--- a/src/mesa/shader/slang/slang_emit.c
+++ b/src/mesa/shader/slang/slang_emit.c
@@ -348,6 +348,10 @@ storage_to_src_reg(struct prog_src_register *src, const slang_ir_storage *st)
    assert(index >= 0);
    while (st->Parent) {
       st = st->Parent;
+      if (st->Index < 0) {
+         /* an error should have been reported already */
+         return;
+      }
       assert(st->Index >= 0);
       index += st->Index;
       swizzle = _slang_swizzle_swizzle(fix_swizzle(st->Swizzle), swizzle);
@@ -1838,9 +1842,17 @@ emit_array_element(slang_emit_info *emitInfo, slang_ir_node *n)
          root = root->Parent;
 
       if (root->File == PROGRAM_STATE_VAR) {
-         GLint index = _slang_alloc_statevar(n, emitInfo->prog->Parameters);
-         assert(n->Store->Index == index);
-         return NULL;
+         GLboolean direct;
+         GLint index =
+            _slang_alloc_statevar(n, emitInfo->prog->Parameters, &direct);
+         if (index < 0) {
+            /* error */
+            return NULL;
+         }
+         if (direct) {
+            n->Store->Index = index;
+            return NULL; /* all done */
+         }
       }
    }
 
@@ -1964,19 +1976,23 @@ emit_struct_field(slang_emit_info *emitInfo, slang_ir_node *n)
     * space for the ones that we actually use!
     */
    if (root->File == PROGRAM_STATE_VAR) {
-      root->Index = _slang_alloc_statevar(n, emitInfo->prog->Parameters);
-      if (root->Index < 0) {
+      GLboolean direct;
+      GLint index = _slang_alloc_statevar(n, emitInfo->prog->Parameters, &direct);
+      if (index < 0) {
          slang_info_log_error(emitInfo->log, "Error parsing state variable");
          return NULL;
       }
-      return NULL;
-   }
-   else {
-      /* do codegen for struct */
-      emit(emitInfo, n->Children[0]);
-      assert(n->Children[0]->Store->Index >= 0);
+      if (direct) {
+         root->Index = index;
+         return NULL; /* all done */
+      }
    }
 
+   /* do codegen for struct */
+   emit(emitInfo, n->Children[0]);
+   assert(n->Children[0]->Store->Index >= 0);
+
+
    fieldOffset = n->Store->Index;
    fieldSize = n->Store->Size;
 
@@ -2074,7 +2090,18 @@ emit_var_ref(slang_emit_info *emitInfo, slang_ir_node *n)
    assert(n->Store->File != PROGRAM_UNDEFINED);
 
    if (n->Store->File == PROGRAM_STATE_VAR && n->Store->Index < 0) {
-      n->Store->Index = _slang_alloc_statevar(n, emitInfo->prog->Parameters);
+      GLboolean direct;
+      GLint index = _slang_alloc_statevar(n, emitInfo->prog->Parameters, &direct);
+      if (index < 0) {
+         /* error */
+         char s[100];
+         snprintf(s, sizeof(s), "Undefined variable '%s'",
+                  (char *) n->Var->a_name);
+         slang_info_log_error(emitInfo->log, s);
+         return NULL;
+      }
+
+      n->Store->Index = index;
    }
    else if (n->Store->File == PROGRAM_UNIFORM) {
       /* mark var as used */