Add GLSL preprocessor.

5 files changed, 1253 insertions, 17 deletions

diff --git a/src/mesa/shader/slang/slang_compile.c b/src/mesa/shader/slang/slang_compile.c
index 46bdf830f9..357d61b246 100644
--- a/src/mesa/shader/slang/slang_compile.c
+++ b/src/mesa/shader/slang/slang_compile.c
@@ -1,6 +1,6 @@
 /*
  * Mesa 3-D graphics library
- * Version:  6.5
+ * Version:  6.6
  *
  * Copyright (C) 2005-2006  Brian Paul   All Rights Reserved.
  *
@@ -1918,10 +1918,11 @@ static GLboolean
 compile_with_grammar (grammar id, const char *source, slang_code_unit *unit, slang_unit_type type,
                       slang_info_log *infolog, slang_code_unit *builtin)
 {
-	byte *prod;
+   byte *prod;
    GLuint size, start, version;
+   slang_string preprocessed;
 
-	/* retrieve version */
+   /* First retrieve the version number. */
    if (!_slang_preprocess_version (source, &version, &start, infolog))
       return GL_FALSE;
 
@@ -1930,22 +1931,31 @@ compile_with_grammar (grammar id, const char *source, slang_code_unit *unit, sla
       return GL_FALSE;
    }
 
-	/* check the syntax and generate its binary representation */
-	if (!grammar_fast_check (id, (const byte *) source + start, &prod, &size, 65536))
-	{
-		char buf[1024];
-		unsigned int pos;
-		grammar_get_last_error ( (unsigned char*) buf, 1024, (int*) &pos);
+   /* Now preprocess the source string. */
+   slang_string_init (&preprocessed);
+   if (!_slang_preprocess_directives (&preprocessed, &source[start], infolog)) {
+      slang_string_free (&preprocessed);
+      slang_info_log_error (infolog, "failed to preprocess the source.");
+      return GL_FALSE;
+   }
+
+   /* Finally check the syntax and generate its binary representation. */
+   if (!grammar_fast_check (id, (const byte *) (slang_string_cstr (&preprocessed)), &prod, &size, 65536)) {
+      char buf[1024];
+      GLint pos;
+
+      slang_string_free (&preprocessed);
+      grammar_get_last_error ((byte *) (buf), sizeof (buf), &pos);
       slang_info_log_error (infolog, buf);
       return GL_FALSE;
-	}
+   }
+   slang_string_free (&preprocessed);
 
-	/* syntax is okay - translate it to internal representation */
+   /* Syntax is okay - translate it to internal representation. */
    if (!compile_binary (prod, unit, type, infolog, builtin, &builtin[SLANG_BUILTIN_TOTAL - 1])) {
       grammar_alloc_free (prod);
       return GL_FALSE;
    }
-
    grammar_alloc_free (prod);
    return GL_TRUE;
 }
diff --git a/src/mesa/shader/slang/slang_preprocess.c b/src/mesa/shader/slang/slang_preprocess.c
index bd9ff9002e..43aa9a1e95 100644
--- a/src/mesa/shader/slang/slang_preprocess.c
+++ b/src/mesa/shader/slang/slang_preprocess.c
@@ -1,6 +1,6 @@
 /*
  * Mesa 3-D graphics library
- * Version:  6.5
+ * Version:  6.6
  *
  * Copyright (C) 2005-2006  Brian Paul   All Rights Reserved.
  *
@@ -32,6 +32,14 @@
 #include "grammar_mesa.h"
 #include "slang_preprocess.h"
 
+static const char *slang_pp_directives_syn =
+#include "library/slang_pp_directives_syn.h"
+;
+
+static const char *slang_pp_expression_syn =
+#include "library/slang_pp_expression_syn.h"
+;
+
 static const char *slang_pp_version_syn =
 #include "library/slang_pp_version_syn.h"
 ;
@@ -40,7 +48,7 @@ static GLvoid
 grammar_error_to_log (slang_info_log *log)
 {
    char buf[1024];
-   int pos;
+   GLint pos;
 
    grammar_get_last_error ((byte *) (buf), sizeof (buf), &pos);
    slang_info_log_error (log, buf);
@@ -75,3 +83,1089 @@ _slang_preprocess_version (const char *text, GLuint *version, GLuint *eaten, sla
    return GL_TRUE;
 }
 
+/*
+ * The preprocessor does the following work.
+ * 1. Remove comments. Each comment block is replaced with a single space and if the
+ *    block contains new-lines, they are preserved. This ensures that line numbers
+ *    stay the same and if a comment block delimits two tokens, the are delitmited
+ *    by the space after comment removal.
+ * 2. Remove preprocessor directives from the source string, checking their syntax and
+ *    executing them if appropriate. Again, new-lines are preserved.
+ * 3. Expand macros.
+ * 4. Tokenize the source string by ensuring there is at least one space between every
+ *    two adjacent tokens.
+ */
+
+#define PP_ANNOTATE 0
+
+static GLvoid
+pp_annotate (slang_string *output, const char *fmt, ...)
+{
+#if PP_ANNOTATE
+   va_list va;
+   char buffer[1024];
+
+   va_start (va, fmt);
+   _mesa_vsprintf (buffer, fmt, va);
+   va_end (va);
+   slang_string_pushs (output, buffer, _mesa_strlen (buffer));
+#else
+   (GLvoid) (output);
+   (GLvoid) (fmt);
+#endif
+}
+
+ /*
+ * The expression is executed on a fixed-sized stack. The PUSH macro makes a runtime
+ * check if the stack is not overflown by too complex expressions. In that situation the
+ * GLSL preprocessor should report internal compiler error.
+ * The BINARYDIV makes a runtime check if the divider is not 0. If it is, it reports
+ * compilation error.
+ */
+
+#define EXECUTION_STACK_SIZE 1024
+
+#define PUSH(x)\
+   do {\
+      if (sp == 0) {\
+         slang_info_log_error (elog, "internal compiler error: preprocessor execution stack overflow.");\
+         return GL_FALSE;\
+      }\
+      stack[--sp] = x;\
+   } while (GL_FALSE)
+
+#define POP(x)\
+   do {\
+      assert (sp < EXECUTION_STACK_SIZE);\
+      x = stack[sp++];\
+   } while (GL_FALSE)
+
+#define BINARY(op)\
+   do {\
+      GLint a, b;\
+      POP(b);\
+      POP(a);\
+      PUSH(a op b);\
+   } while (GL_FALSE)
+
+#define BINARYDIV(op)\
+   do {\
+      GLint a, b;\
+      POP(b);\
+      POP(a);\
+      if (b == 0) {\
+         slang_info_log_error (elog, "division by zero in preprocessor expression.");\
+         return GL_FALSE;\
+      }\
+      PUSH(a op b);\
+   } while (GL_FALSE)
+
+#define UNARY(op)\
+   do {\
+      GLint a;\
+      POP(a);\
+      PUSH(op a);\
+   } while (GL_FALSE)
+
+#define OP_END          0
+#define OP_PUSHINT      1
+#define OP_LOGICALOR    2
+#define OP_LOGICALAND   3
+#define OP_OR           4
+#define OP_XOR          5
+#define OP_AND          6
+#define OP_EQUAL        7
+#define OP_NOTEQUAL     8
+#define OP_LESSEQUAL    9
+#define OP_GREATEREQUAL 10
+#define OP_LESS         11
+#define OP_GREATER      12
+#define OP_LEFTSHIFT    13
+#define OP_RIGHTSHIFT   14
+#define OP_ADD          15
+#define OP_SUBTRACT     16
+#define OP_MULTIPLY     17
+#define OP_DIVIDE       18
+#define OP_MODULUS      19
+#define OP_PLUS         20
+#define OP_MINUS        21
+#define OP_NEGATE       22
+#define OP_COMPLEMENT   23
+
+static GLboolean
+execute_expression (slang_string *output, const byte *code, GLuint *pi, GLint *result,
+                    slang_info_log *elog)
+{
+   GLuint i = *pi;
+   GLint stack[EXECUTION_STACK_SIZE];
+   GLuint sp = EXECUTION_STACK_SIZE;
+
+   while (code[i] != OP_END) {
+      switch (code[i++]) {
+         case OP_PUSHINT:
+            i++;
+            PUSH(_mesa_atoi ((const char *) (&code[i])));
+            i += _mesa_strlen ((const char *) (&code[i])) + 1;
+            break;
+         case OP_LOGICALOR:
+            BINARY(||);
+            break;
+         case OP_LOGICALAND:
+            BINARY(&&);
+            break;
+         case OP_OR:
+            BINARY(|);
+            break;
+         case OP_XOR:
+            BINARY(^);
+            break;
+         case OP_AND:
+            BINARY(&);
+            break;
+         case OP_EQUAL:
+            BINARY(==);
+            break;
+         case OP_NOTEQUAL:
+            BINARY(!=);
+            break;
+         case OP_LESSEQUAL:
+            BINARY(<=);
+            break;
+         case OP_GREATEREQUAL:
+            BINARY(>=);
+            break;
+         case OP_LESS:
+            BINARY(<);
+            break;
+         case OP_GREATER:
+            BINARY(>);
+            break;
+         case OP_LEFTSHIFT:
+            BINARY(<<);
+            break;
+         case OP_RIGHTSHIFT:
+            BINARY(>>);
+            break;
+         case OP_ADD:
+            BINARY(+);
+            break;
+         case OP_SUBTRACT:
+            BINARY(-);
+            break;
+         case OP_MULTIPLY:
+            BINARY(*);
+            break;
+         case OP_DIVIDE:
+            BINARYDIV(/);
+            break;
+         case OP_MODULUS:
+            BINARYDIV(%);
+            break;
+         case OP_PLUS:
+            UNARY(+);
+            break;
+         case OP_MINUS:
+            UNARY(-);
+            break;
+         case OP_NEGATE:
+            UNARY(!);
+            break;
+         case OP_COMPLEMENT:
+            UNARY(~);
+            break;
+         default:
+            assert (0);
+      }
+   }
+
+   /* Write-back the index skipping the OP_END. */
+   *pi = i + 1;
+
+   /* There should be exactly one value left on the stack. This is our result. */
+   POP(*result);
+   pp_annotate (output, "%d ", *result);
+   assert (sp == EXECUTION_STACK_SIZE);
+   return GL_TRUE;
+}
+
+/*
+ * Function execute_expressions() executes up to 2 expressions. The second expression is there
+ * for the #line directive which takes 1 or 2 expressions that indicate line and file numbers.
+ * If it fails, it returns 0. If it succeeds, it returns the number of executed expressions.
+ */
+
+#define EXP_END        0
+#define EXP_EXPRESSION 1
+
+static GLuint
+execute_expressions (slang_string *output, grammar eid, const byte *expr, GLint results[2],
+                     slang_info_log *elog)
+{
+   GLint success;
+   byte *code;
+   GLuint size, count = 0;
+
+   success = grammar_fast_check (eid, expr, &code, &size, 64);
+   if (success) {
+      GLuint i = 0;
+
+      while (code[i++] == EXP_EXPRESSION) {
+         assert (count < 2);
+
+         if (!execute_expression (output, code, &i, &results[count], elog)) {
+            count = 0;
+            break;
+         }
+         count++;
+      }
+      grammar_alloc_free (code);
+   }
+   else {
+      slang_info_log_error (elog, "syntax error in preprocessor expression.");\
+   }
+   return count;
+}
+
+/*
+ * The pp_symbol structure is used to hold macro definitions and macro formal parameters. The
+ * pp_symbols strcture is a collection of pp_symbol. It is used both for storing macro formal
+ * parameters and all global macro definitions. Making this unification wastes some memory,
+ * becuse macro formal parameters don't need further lists of symbols. We lose 8 bytes per
+ * formal parameter here, but making this we can use the same code to substitute macro parameters
+ * as well as macros in the source string.
+ */
+
+typedef struct
+{
+   struct pp_symbol_ *symbols;
+   GLuint count;
+} pp_symbols;
+
+static GLvoid
+pp_symbols_init (pp_symbols *self)
+{
+   self->symbols = NULL;
+   self->count = 0;
+}
+
+static GLvoid
+pp_symbols_free (pp_symbols *);
+
+typedef struct pp_symbol_
+{
+   slang_string name;
+   slang_string replacement;
+   pp_symbols parameters;
+} pp_symbol;
+
+static GLvoid
+pp_symbol_init (pp_symbol *self)
+{
+   slang_string_init (&self->name);
+   slang_string_init (&self->replacement);
+   pp_symbols_init (&self->parameters);
+}
+
+static GLvoid
+pp_symbol_free (pp_symbol *self)
+{
+   slang_string_free (&self->name);
+   slang_string_free (&self->replacement);
+   pp_symbols_free (&self->parameters);
+}
+
+static GLvoid
+pp_symbol_reset (pp_symbol *self)
+{
+   /* Leave symbol name intact. */
+   slang_string_reset (&self->replacement);
+   pp_symbols_free (&self->parameters);
+   pp_symbols_init (&self->parameters);
+}
+
+static GLvoid
+pp_symbols_free (pp_symbols *self)
+{
+   GLuint i;
+
+   for (i = 0; i < self->count; i++)
+      pp_symbol_free (&self->symbols[i]);
+   _mesa_free (self->symbols);
+}
+
+static pp_symbol *
+pp_symbols_push (pp_symbols *self)
+{
+   self->symbols = (pp_symbol *) (_mesa_realloc (self->symbols, self->count * sizeof (pp_symbol),
+                                                 (self->count + 1) * sizeof (pp_symbol)));
+   if (self->symbols == NULL)
+      return NULL;
+   pp_symbol_init (&self->symbols[self->count]);
+   return &self->symbols[self->count++];
+}
+
+static GLboolean
+pp_symbols_erase (pp_symbols *self, pp_symbol *symbol)
+{
+   assert (symbol >= self->symbols && symbol < self->symbols + self->count);
+
+   self->count--;
+   pp_symbol_free (symbol);
+   if (symbol < self->symbols + self->count)
+      _mesa_memcpy (symbol, symbol + 1, sizeof (pp_symbol) * (self->symbols + self->count - symbol));
+   self->symbols = (pp_symbol *) (_mesa_realloc (self->symbols, (self->count + 1) * sizeof (pp_symbol),
+                                                 self->count * sizeof (pp_symbol)));
+   return self->symbols != NULL;
+}
+
+static pp_symbol *
+pp_symbols_find (pp_symbols *self, const char *name)
+{
+   GLuint i;
+
+   for (i = 0; i < self->count; i++)
+      if (_mesa_strcmp (name, slang_string_cstr (&self->symbols[i].name)) == 0)
+         return &self->symbols[i];
+   return NULL;
+}
+
+/*
+ * The condition context of a single #if/#else/#endif level. Those can be nested, so there
+ * is a stack of condition contexts.
+ * There is a special global context on the bottom of the stack. It is there to simplify
+ * context handling.
+ */
+
+typedef struct
+{
+   GLboolean current;         /* The condition value of this level. */
+   GLboolean effective;       /* The effective product of current condition, outer level conditions
+                               * and position within #if-#else-#endif sections. */
+   GLboolean else_allowed;    /* TRUE if in #if-#else section, FALSE if in #else-#endif section
+                               * and for global context. */
+   GLboolean endif_required;  /* FALSE for global context only. */
+} pp_cond_ctx;
+
+/* Should be enuff. */
+#define CONDITION_STACK_SIZE 64
+
+typedef struct
+{
+   pp_cond_ctx stack[CONDITION_STACK_SIZE];
+   pp_cond_ctx *top;
+} pp_cond_stack;
+
+static GLboolean
+pp_cond_stack_push (pp_cond_stack *self, slang_info_log *elog)
+{
+   if (self->top == self->stack) {
+      slang_info_log_error (elog, "internal compiler error: preprocessor condition stack overflow.");
+      return GL_FALSE;
+   }
+   self->top--;
+   return GL_TRUE;
+}
+
+static GLvoid
+pp_cond_stack_reevaluate (pp_cond_stack *self)
+{
+   /* There must be at least 2 conditions on the stack - one global and one being evaluated. */
+   assert (self->top <= &self->stack[CONDITION_STACK_SIZE - 2]);
+
+   self->top->effective = self->top->current && self->top[1].effective;
+}
+
+/*
+ * Extension enables through #extension directive.
+ * NOTE: Currently, only enable/disable state is stored.
+ */
+
+typedef struct
+{
+   GLboolean MESA_shader_debug;        /* GL_MESA_shader_debug enable */
+} pp_ext;
+
+/*
+ * Disable all extensions. Called at startup and on #extension all: disable.
+ */
+static GLvoid
+pp_ext_disable_all (pp_ext *self)
+{
+   self->MESA_shader_debug = GL_FALSE;
+}
+
+static GLvoid
+pp_ext_init (pp_ext *self)
+{
+   pp_ext_disable_all (self);
+   /* Other initialization code goes here. */
+}
+
+static GLboolean
+pp_ext_set (pp_ext *self, const char *name, GLboolean enable)
+{
+   if (_mesa_strcmp (name, "MESA_shader_debug") == 0)
+      self->MESA_shader_debug = enable;
+   /* Next extension name tests go here. */
+   else
+      return GL_FALSE;
+   return GL_TRUE;
+}
+
+/*
+ * The state of preprocessor: current line, file and version number, list of all defined macros
+ * and the #if/#endif context.
+ */
+
+typedef struct
+{
+   GLint line;
+   GLint file;
+   GLint version;
+   pp_symbols symbols;
+   pp_ext ext;
+   slang_info_log *elog;
+   pp_cond_stack cond;
+} pp_state;
+
+static GLvoid
+pp_state_init (pp_state *self, slang_info_log *elog)
+{
+   self->line = 0;
+   self->file = 1;
+   self->version = 110;
+   pp_symbols_init (&self->symbols);
+   pp_ext_init (&self->ext);
+   self->elog = elog;
+
+   /* Initialize condition stack and create the global context. */
+   self->cond.top = &self->cond.stack[CONDITION_STACK_SIZE - 1];
+   self->cond.top->current = GL_TRUE;
+   self->cond.top->effective = GL_TRUE;
+   self->cond.top->else_allowed = GL_FALSE;
+   self->cond.top->endif_required = GL_FALSE;
+}
+
+static GLvoid
+pp_state_free (pp_state *self)
+{
+   pp_symbols_free (&self->symbols);
+}
+
+#define IS_FIRST_ID_CHAR(x) (((x) >= 'a' && (x) <= 'z') || ((x) >= 'A' && (x) <= 'Z') || (x) == '_')
+#define IS_NEXT_ID_CHAR(x) (IS_FIRST_ID_CHAR(x) || ((x) >= '0' && (x) <= '9'))
+#define IS_WHITE(x) ((x) == ' ' || (x) == '\n')
+#define IS_NULL(x) ((x) == '\0')
+
+#define SKIP_WHITE(x) do { while (IS_WHITE(*(x))) (x)++; } while (GL_FALSE)
+
+typedef struct
+{
+   slang_string *output;
+   const char *input;
+   pp_state *state;
+} expand_state;
+
+static GLboolean
+expand_defined (expand_state *e, slang_string *buffer)
+{
+   GLboolean in_paren = GL_FALSE;
+   const char *id;
+
+   /* Parse the optional opening parenthesis. */
+   SKIP_WHITE(e->input);
+   if (*e->input == '(') {
+      e->input++;
+      in_paren = GL_TRUE;
+      SKIP_WHITE(e->input);
+   }
+
+   /* Parse operand. */
+   if (!IS_FIRST_ID_CHAR(*e->input)) {
+      slang_info_log_error (e->state->elog,
+                            "preprocess error: identifier expected after operator 'defined'.");
+      return GL_FALSE;
+   }
+   slang_string_reset (buffer);
+   slang_string_pushc (buffer, *e->input++);
+   while (IS_NEXT_ID_CHAR(*e->input))
+      slang_string_pushc (buffer, *e->input++);
+   id = slang_string_cstr (buffer);
+
+   /* Check if the operand is defined. Output 1 if it is defined, output 0 if not. */
+   if (pp_symbols_find (&e->state->symbols, id) == NULL)
+      slang_string_pushs (e->output, " 0 ", 3);
+   else
+      slang_string_pushs (e->output, " 1 ", 3);
+
+   /* Parse the closing parentehesis if the opening one was there. */
+   if (in_paren) {
+      SKIP_WHITE(e->input);
+      if (*e->input != ')') {
+         slang_info_log_error (e->state->elog, "preprocess error: ')' expected.");
+         return GL_FALSE;
+      }
+      e->input++;
+      SKIP_WHITE(e->input);
+   }
+   return GL_TRUE;
+}
+
+static GLboolean
+expand (expand_state *, pp_symbols *);
+
+static GLboolean
+expand_symbol (expand_state *e, pp_symbol *symbol)
+{
+   expand_state es;
+
+   /* If the macro has some parameters, we need to parse them. */
+   if (symbol->parameters.count != 0) {
+      GLuint i;
+
+      /* Parse the opening parenthesis. */
+      SKIP_WHITE(e->input);
+      if (*e->input != '(') {
+         slang_info_log_error (e->state->elog, "preprocess error: '(' expected.");
+         return GL_FALSE;
+      }
+      e->input++;
+      SKIP_WHITE(e->input);
+
+      /* Parse macro actual parameters. This can be anything, separated by a colon.
+       * TODO: What about nested/grouped parameters by parenthesis? */
+      for (i = 0; i < symbol->parameters.count; i++) {
+         if (*e->input == ')') {
+            slang_info_log_error (e->state->elog, "preprocess error: unexpected ')'.");
+            return GL_FALSE;
+         }
+
+         /* Eat all characters up to the comma or closing parentheses. */
+         pp_symbol_reset (&symbol->parameters.symbols[i]);
+         while (!IS_NULL(*e->input) && *e->input != ',' && *e->input != ')')
+            slang_string_pushc (&symbol->parameters.symbols[i].replacement, *e->input++);
+
+         /* If it was not the last paremeter, skip the comma. Otherwise, skip the
+          * closing parentheses. */
+         if (i + 1 == symbol->parameters.count) {
+            /* This is the last paremeter - skip the closing parentheses. */
+            if (*e->input != ')') {
+               slang_info_log_error (e->state->elog, "preprocess error: ')' expected.");
+               return GL_FALSE;
+            }
+            e->input++;
+            SKIP_WHITE(e->input);
+         }
+         else {
+            /* Skip the separating comma. */
+            if (*e->input != ',') {
+               slang_info_log_error (e->state->elog, "preprocess error: ',' expected.");
+               return GL_FALSE;
+            }
+            e->input++;
+            SKIP_WHITE(e->input);
+         }
+      }
+   }
+
+   /* Expand the macro. Use its parameters as a priority symbol list to expand
+    * macro parameters correctly. */
+   es.output = e->output;
+   es.input = slang_string_cstr (&symbol->replacement);
+   es.state = e->state;
+   slang_string_pushc (e->output, ' ');
+   if (!expand (&es, &symbol->parameters))
+      return GL_FALSE;
+   slang_string_pushc (e->output, ' ');
+   return GL_TRUE;
+}
+
+/*
+ * Function expand() expands source text from <input> to <output>. The expansion is made using
+ * the list passed in <symbols> parameter. It allows us to expand macro formal parameters with
+ * actual parameters. The global list of symbols from pp state is used when doing a recursive
+ * call of expand().
+ */
+
+static GLboolean
+expand (expand_state *e, pp_symbols *symbols)
+{
+   while (!IS_NULL(*e->input)) {
+      if (IS_FIRST_ID_CHAR(*e->input)) {
+         slang_string buffer;
+         const char *id;
+
+         /* Parse the identifier. */
+         slang_string_init (&buffer);
+         slang_string_pushc (&buffer, *e->input++);
+         while (IS_NEXT_ID_CHAR(*e->input))
+            slang_string_pushc (&buffer, *e->input++);
+         id = slang_string_cstr (&buffer);
+
+         /* Now check if the identifier is special in some way. The "defined" identifier is
+          * actually an operator that we must handle here and expand it either to " 0 " or " 1 ".
+          * The other identifiers start with "__" and we expand it to appropriate values
+          * taken from the preprocessor state. */
+         if (_mesa_strcmp (id, "defined") == 0) {
+            if (!expand_defined (e, &buffer))
+               return GL_FALSE;
+         }
+         else if (_mesa_strcmp (id, "__LINE__") == 0) {
+            slang_string_pushc (e->output, ' ');
+            slang_string_pushi (e->output, e->state->line);
+            slang_string_pushc (e->output, ' ');
+         }
+         else if (_mesa_strcmp (id, "__FILE__") == 0) {
+            slang_string_pushc (e->output, ' ');
+            slang_string_pushi (e->output, e->state->file);
+            slang_string_pushc (e->output, ' ');
+         }
+         else if (_mesa_strcmp (id, "__VERSION__") == 0) {
+            slang_string_pushc (e->output, ' ');
+            slang_string_pushi (e->output, e->state->version);
+            slang_string_pushc (e->output, ' ');
+         }
+         else {
+            pp_symbol *symbol;
+
+            /* The list of symbols from <symbols> take precedence over the list from <state>.
+             * Note that in some cases this is the same list so avoid double look-up. */
+            symbol = pp_symbols_find (symbols, id);
+            if (symbol == NULL && symbols != &e->state->symbols)
+               symbol = pp_symbols_find (&e->state->symbols, id);
+
+            /* If the symbol was found, recursively expand its definition. */
+            if (symbol != NULL) {
+               if (!expand_symbol (e, symbol)) {
+                  slang_string_free (&buffer);
+                  return GL_FALSE;
+               }
+            }
+            else {
+               slang_string_push (e->output, &buffer);
+            }
+         }
+         slang_string_free (&buffer);
+      }
+      else if (IS_WHITE(*e->input)) {
+         slang_string_pushc (e->output, *e->input++);
+      }
+      else {
+         while (!IS_WHITE(*e->input) && !IS_NULL(*e->input) && !IS_FIRST_ID_CHAR(*e->input))
+            slang_string_pushc (e->output, *e->input++);
+      }
+   }
+   return GL_TRUE;
+}
+
+static GLboolean
+parse_if (slang_string *output, const byte *prod, GLuint *pi, GLint *result, pp_state *state,
+          grammar eid)
+{
+   const char *text;
+   GLuint len;
+
+   text = (const char *) (&prod[*pi]);
+   len = _mesa_strlen (text);
+
+   if (state->cond.top->effective) {
+      slang_string expr;
+      GLuint count;
+      GLint results[2];
+      expand_state es;
+
+      /* Expand the expression. */
+      slang_string_init (&expr);
+      es.output = &expr;
+      es.input = text;
+      es.state = state;
+      if (!expand (&es, &state->symbols))
+         return GL_FALSE;
+
+      /* Execute the expression. */
+      count = execute_expressions (output, eid, (const byte *) (slang_string_cstr (&expr)),
+                                   results, state->elog);
+      slang_string_free (&expr);
+      if (count != 1)
+         return GL_FALSE;
+      *result = results[0];
+   }
+   else {
+      /* The directive is dead. */
+      *result = 0;
+   }
+
+   *pi += len + 1;
+   return GL_TRUE;
+}
+
+#define ESCAPE_TOKEN 0
+
+#define TOKEN_END       0
+#define TOKEN_DEFINE    1
+#define TOKEN_UNDEF     2
+#define TOKEN_IF        3
+#define TOKEN_ELSE      4
+#define TOKEN_ELIF      5
+#define TOKEN_ENDIF     6
+#define TOKEN_ERROR     7
+#define TOKEN_PRAGMA    8
+#define TOKEN_EXTENSION 9
+#define TOKEN_LINE      10
+
+#define PARAM_END       0
+#define PARAM_PARAMETER 1
+
+#define BEHAVIOR_REQUIRE 1
+#define BEHAVIOR_ENABLE  2
+#define BEHAVIOR_WARN    3
+#define BEHAVIOR_DISABLE 4
+
+static GLboolean
+preprocess_source (slang_string *output, const char *source, grammar pid, grammar eid,
+                   slang_info_log *elog)
+{
+   byte *prod;
+   GLuint size, i;
+   pp_state state;
+
+   if (!grammar_fast_check (pid, (const byte *) (source), &prod, &size, 65536)) {
+      grammar_error_to_log (elog);
+      return GL_FALSE;
+   }
+
+   pp_state_init (&state, elog);
+
+   i = 0;
+   while (i < size) {
+      if (prod[i] != ESCAPE_TOKEN) {
+         if (state.cond.top->effective) {
+            slang_string input;
+            expand_state es;
+
+            /* Eat only one line of source code to expand it.
+             * FIXME: This approach has one drawback. If a macro with parameters spans across
+             *        multiple lines, the preprocessor will raise an error. */
+            slang_string_init (&input);
+            while (prod[i] != '\0' && prod[i] != '\n')
+               slang_string_pushc (&input, prod[i++]);
+            if (prod[i] != '\0')
+               slang_string_pushc (&input, prod[i++]);
+
+            /* Increment line number. */
+            state.line++;
+
+            es.output = output;
+            es.input = slang_string_cstr (&input);
+            es.state = &state;
+            if (!expand (&es, &state.symbols))
+               goto error;
+
+            slang_string_free (&input);
+         }
+         else {
+            /* Condition stack is disabled - keep track on line numbers and output only newlines. */
+            if (prod[i] == '\n') {
+               state.line++;
+               /*pp_annotate (output, "%c", prod[i]);*/
+            }
+            else {
+               /*pp_annotate (output, "%c", prod[i]);*/
+            }
+            i++;
+         }
+      }
+      else {
+         const char *id;
+         GLuint idlen;
+
+         i++;
+         switch (prod[i++]) {
+
+         case TOKEN_END:
+            /* End of source string.
+               * Check if all #ifs have been terminated by matching #endifs.
+               * On condition stack there should be only the global condition context. */
+            if (state.cond.top->endif_required) {
+               slang_info_log_error (elog, "end of source without matching #endif.");
+               return GL_FALSE;
+            }
+            break;
+
+         case TOKEN_DEFINE:
+            {
+               pp_symbol *symbol = NULL;
+
+               /* Parse macro name. */
+               id = (const char *) (&prod[i]);
+               idlen = _mesa_strlen (id);
+               if (state.cond.top->effective) {
+                  pp_annotate (output, "// #define %s(", id);
+
+                  /* If the symbol is already defined, override it. */
+                  symbol = pp_symbols_find (&state.symbols, id);
+                  if (symbol == NULL) {
+                     symbol = pp_symbols_push (&state.symbols);
+                     if (symbol == NULL)
+                        goto error;
+                     slang_string_pushs (&symbol->name, id, idlen);
+                  }
+                  else {
+                     pp_symbol_reset (symbol);
+                  }
+               }
+               i += idlen + 1;
+
+               /* Parse optional macro parameters. */
+               while (prod[i++] != PARAM_END) {
+                  if (state.cond.top->effective) {
+                     pp_symbol *param;
+
+                     id = (const char *) (&prod[i]);
+                     idlen = _mesa_strlen (id);
+                     pp_annotate (output, "%s, ", id);
+                     param = pp_symbols_push (&symbol->parameters);
+                     if (param == NULL)
+                        goto error;
+                     slang_string_pushs (&param->name, id, idlen);
+                  }
+                  i += idlen + 1;
+               }
+
+               /* Parse macro replacement. */
+               id = (const char *) (&prod[i]);
+               idlen = _mesa_strlen (id);
+               if (state.cond.top->effective) {
+                  pp_annotate (output, ") %s", id);
+                  slang_string_pushs (&symbol->replacement, id, idlen);
+               }
+               i += idlen + 1;
+            }
+            break;
+
+         case TOKEN_UNDEF:
+            id = (const char *) (&prod[i]);
+            i += _mesa_strlen (id) + 1;
+            if (state.cond.top->effective) {
+               pp_symbol *symbol;
+
+               pp_annotate (output, "// #undef %s", id);
+               /* Try to find symbol with given name and remove it. */
+               symbol = pp_symbols_find (&state.symbols, id);
+               if (symbol != NULL)
+                  if (!pp_symbols_erase (&state.symbols, symbol))
+                     goto error;
+            }
+            break;
+
+         case TOKEN_IF:
+            {
+               GLint result;
+
+               /* Parse #if expression end execute it. */
+               pp_annotate (output, "// #if ");
+               if (!parse_if (output, prod, &i, &result, &state, eid))
+                  goto error;
+
+               /* Push new condition on the stack. */
+               if (!pp_cond_stack_push (&state.cond, state.elog))
+                  goto error;
+               state.cond.top->current = result ? GL_TRUE : GL_FALSE;
+               state.cond.top->else_allowed = GL_TRUE;
+               state.cond.top->endif_required = GL_TRUE;
+               pp_cond_stack_reevaluate (&state.cond);
+            }
+            break;
+
+         case TOKEN_ELSE:
+            /* Check if #else is alloved here. */
+            if (!state.cond.top->else_allowed) {
+               slang_info_log_error (elog, "#else without matching #if.");
+               goto error;
+            }
+
+            /* Negate current condition and reevaluate it. */
+            state.cond.top->current = !state.cond.top->current;
+            state.cond.top->else_allowed = GL_FALSE;
+            pp_cond_stack_reevaluate (&state.cond);
+            if (state.cond.top->effective)
+               pp_annotate (output, "// #else");
+            break;
+
+         case TOKEN_ELIF:
+            /* Check if #elif is alloved here. */
+            if (!state.cond.top->else_allowed) {
+               slang_info_log_error (elog, "#elif without matching #if.");
+               goto error;
+            }
+
+            /* Negate current condition and reevaluate it. */
+            state.cond.top->current = !state.cond.top->current;
+            pp_cond_stack_reevaluate (&state.cond);
+
+            if (state.cond.top->effective)
+               pp_annotate (output, "// #elif ");
+
+            {
+               GLint result;
+
+               /* Parse #elif expression end execute it. */
+               if (!parse_if (output, prod, &i, &result, &state, eid))
+                  goto error;
+
+               /* Update current condition and reevaluate it. */
+               state.cond.top->current = result ? GL_TRUE : GL_FALSE;
+               pp_cond_stack_reevaluate (&state.cond);
+            }
+            break;
+
+         case TOKEN_ENDIF:
+            /* Check if #endif is alloved here. */
+            if (!state.cond.top->endif_required) {
+               slang_info_log_error (elog, "#endif without matching #if.");
+               goto error;
+            }
+
+            /* Pop the condition off the stack. */
+            state.cond.top++;
+            if (state.cond.top->effective)
+               pp_annotate (output, "// #endif");
+            break;
+
+         case TOKEN_EXTENSION:
+            /* Parse the extension name. */
+            id = (const char *) (&prod[i]);
+            i += _mesa_strlen (id) + 1;
+            if (state.cond.top->effective)
+               pp_annotate (output, "// #extension %s: ", id);
+
+            /* Parse and apply extension behavior. */
+            if (state.cond.top->effective) {
+               switch (prod[i++]) {
+
+               case BEHAVIOR_REQUIRE:
+                  pp_annotate (output, "require");
+                  if (!pp_ext_set (&state.ext, id, GL_TRUE)) {
+                     if (_mesa_strcmp (id, "all") == 0) {
+                        slang_info_log_error (elog, "require: bad behavior for #extension all.");
+                        goto error;
+                     }
+                     else {
+                        slang_info_log_error (elog, "%s: required extension is not supported.", id);
+                        goto error;
+                     }
+                  }
+                  break;
+
+               case BEHAVIOR_ENABLE:
+                  pp_annotate (output, "enable");
+                  if (!pp_ext_set (&state.ext, id, GL_TRUE)) {
+                     if (_mesa_strcmp (id, "all") == 0) {
+                        slang_info_log_error (elog, "enable: bad behavior for #extension all.");
+                        goto error;
+                     }
+                     else {
+                        slang_info_log_warning (elog, "%s: enabled extension is not supported.", id);
+                     }
+                  }
+                  break;
+
+               case BEHAVIOR_WARN:
+                  pp_annotate (output, "warn");
+                  if (!pp_ext_set (&state.ext, id, GL_TRUE)) {
+                     if (_mesa_strcmp (id, "all") != 0) {
+                        slang_info_log_warning (elog, "%s: enabled extension is not supported.", id);
+                     }
+                  }
+                  break;
+
+               case BEHAVIOR_DISABLE:
+                  pp_annotate (output, "disable");
+                  if (!pp_ext_set (&state.ext, id, GL_FALSE)) {
+                     if (_mesa_strcmp (id, "all") == 0) {
+                        pp_ext_disable_all (&state.ext);
+                     }
+                     else {
+                        slang_info_log_warning (elog, "%s: disabled extension is not supported.", id);
+                     }
+                  }
+                  break;
+
+               default:
+                  assert (0);
+               }
+            }
+            break;
+
+         case TOKEN_LINE:
+            id = (const char *) (&prod[i]);
+            i += _mesa_strlen (id) + 1;
+
+            if (state.cond.top->effective) {
+               slang_string buffer;
+               GLuint count;
+               GLint results[2];
+               expand_state es;
+
+               slang_string_init (&buffer);
+               state.line++;
+               es.output = &buffer;
+               es.input = id;
+               es.state = &state;
+               if (!expand (&es, &state.symbols))
+                  goto error;
+
+               pp_annotate (output, "// #line ");
+               count = execute_expressions (output, eid,
+                                             (const byte *) (slang_string_cstr (&buffer)),
+                                             results, state.elog);
+               slang_string_free (&buffer);
+               if (count == 0)
+                  goto error;
+
+               state.line = results[0] - 1;
+               if (count == 2)
+                  state.file = results[1];
+            }
+            break;
+         }
+      }
+   }
+
+   /* Check for missing #endifs. */
+   if (state.cond.top->endif_required) {
+      slang_info_log_error (elog, "#endif expected but end of source found.");
+      goto error;
+   }
+
+   pp_state_free (&state);
+   return GL_TRUE;
+
+error:
+   pp_state_free (&state);
+   return GL_FALSE;
+}
+
+GLboolean
+_slang_preprocess_directives (slang_string *output, const char *input, slang_info_log *elog)
+{
+   grammar pid, eid;
+   GLboolean success;
+
+   pid = grammar_load_from_text ((const byte *) (slang_pp_directives_syn));
+   if (pid == 0) {
+      grammar_error_to_log (elog);
+      return GL_FALSE;
+   }
+   eid = grammar_load_from_text ((const byte *) (slang_pp_expression_syn));
+   if (eid == 0) {
+      grammar_error_to_log (elog);
+      grammar_destroy (pid);
+      return GL_FALSE;
+   }
+   success = preprocess_source (output, input, pid, eid, elog);
+   grammar_destroy (eid);
+   grammar_destroy (pid);
+   return success;
+}
+
diff --git a/src/mesa/shader/slang/slang_preprocess.h b/src/mesa/shader/slang/slang_preprocess.h
index b55852dc4c..f83e6e6e3f 100644
--- a/src/mesa/shader/slang/slang_preprocess.h
+++ b/src/mesa/shader/slang/slang_preprocess.h
@@ -1,6 +1,6 @@
 /*
  * Mesa 3-D graphics library
- * Version:  6.5
+ * Version:  6.6
  *
  * Copyright (C) 2005-2006  Brian Paul   All Rights Reserved.
  *
@@ -34,6 +34,9 @@ extern "C" {
 GLboolean
 _slang_preprocess_version (const char *, GLuint *, GLuint *, slang_info_log *);
 
+GLboolean
+_slang_preprocess_directives (slang_string *output, const char *input, slang_info_log *);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/mesa/shader/slang/slang_utility.c b/src/mesa/shader/slang/slang_utility.c
index 20ea6abae5..54fcc8a238 100644
--- a/src/mesa/shader/slang/slang_utility.c
+++ b/src/mesa/shader/slang/slang_utility.c
@@ -1,6 +1,6 @@
 /*
  * Mesa 3-D graphics library
- * Version:  6.5
+ * Version:  6.6
  *
  * Copyright (C) 2005-2006  Brian Paul   All Rights Reserved.
  *
@@ -36,6 +36,99 @@ char *slang_string_concat (char *dst, const char *src)
 	return _mesa_strcpy (dst + _mesa_strlen (dst), src);
 }
 
+/* slang_string */
+
+GLvoid
+slang_string_init (slang_string *self)
+{
+   self->data = NULL;
+   self->capacity = 0;
+   self->length = 0;
+   self->fail = GL_FALSE;
+}
+
+GLvoid
+slang_string_free (slang_string *self)
+{
+   if (self->data != NULL)
+      _mesa_free (self->data);
+}
+
+GLvoid
+slang_string_reset (slang_string *self)
+{
+   self->length = 0;
+   self->fail = GL_FALSE;
+}
+
+static GLboolean
+grow (slang_string *self, GLuint size)
+{
+   if (self->fail)
+      return GL_FALSE;
+   if (size > self->capacity) {
+      /* do not overflow 32-bit range */
+      assert (size < 0x80000000);
+
+      self->data = (char *) (_mesa_realloc (self->data, self->capacity, size * 2));
+      self->capacity = size * 2;
+      if (self->data == NULL) {
+         self->capacity = 0;
+         self->fail = GL_TRUE;
+         return GL_FALSE;
+      }
+   }
+   return GL_TRUE;
+}
+
+GLvoid
+slang_string_push (slang_string *self, const slang_string *str)
+{
+   if (str->fail) {
+      self->fail = GL_TRUE;
+      return;
+   }
+   if (grow (self, self->length + str->length)) {
+      _mesa_memcpy (&self->data[self->length], str->data, str->length);
+      self->length += str->length;
+   }
+}
+
+GLvoid
+slang_string_pushc (slang_string *self, const char c)
+{
+   if (grow (self, self->length + 1)) {
+      self->data[self->length] = c;
+      self->length++;
+   }
+}
+
+GLvoid
+slang_string_pushs (slang_string *self, const char *cstr, GLuint len)
+{
+   if (grow (self, self->length + len)) {
+      _mesa_memcpy (&self->data[self->length], cstr, len);
+      self->length += len;
+   }
+}
+
+GLvoid
+slang_string_pushi (slang_string *self, GLint i)
+{
+   char buffer[12];
+
+   _mesa_sprintf (buffer, "%d", i);
+   slang_string_pushs (self, buffer, strlen (buffer));
+}
+
+const char *
+slang_string_cstr (slang_string *self)
+{
+   if (grow (self, self->length + 1))
+      self->data[self->length] = '\0';
+   return self->data;
+}
+
 /* slang_atom_pool */
 
 void slang_atom_pool_construct (slang_atom_pool *pool)
diff --git a/src/mesa/shader/slang/slang_utility.h b/src/mesa/shader/slang/slang_utility.h
index 7a1997e559..565de4e4b0 100644
--- a/src/mesa/shader/slang/slang_utility.h
+++ b/src/mesa/shader/slang/slang_utility.h
@@ -1,6 +1,6 @@
 /*
  * Mesa 3-D graphics library
- * Version:  6.5
+ * Version:  6.6
  *
  * Copyright (C) 2005-2006  Brian Paul   All Rights Reserved.
  *
@@ -44,6 +44,42 @@ extern "C" {
 
 char *slang_string_concat (char *, const char *);
 
+/* slang_string */
+
+typedef struct
+{
+   char *data;
+   GLuint length;
+   GLuint capacity;
+   GLboolean fail;
+} slang_string;
+
+GLvoid
+slang_string_init (slang_string *);
+
+GLvoid
+slang_string_free (slang_string *);
+
+GLvoid
+slang_string_reset (slang_string *);
+
+GLvoid
+slang_string_push (slang_string *, const slang_string *);
+
+GLvoid
+slang_string_pushc (slang_string *, const char);
+
+GLvoid
+slang_string_pushs (slang_string *, const char *, GLuint);
+
+GLvoid
+slang_string_pushi (slang_string *, GLint);
+
+const char *
+slang_string_cstr (slang_string *);
+
+/* slang_atom */
+
 typedef GLvoid *slang_atom;
 
 #define SLANG_ATOM_NULL ((slang_atom) 0)