4 files changed, 113 insertions, 90 deletions

diff --git a/mesalib/src/glsl/ast_function.cpp b/mesalib/src/glsl/ast_function.cpp
index bdb73f487..8bcf48dfd 100644
--- a/mesalib/src/glsl/ast_function.cpp
+++ b/mesalib/src/glsl/ast_function.cpp
@@ -442,13 +442,21 @@ process_array_constructor(exec_list *instructions,
       ir_rvalue *ir = (ir_rvalue *) n;
       ir_rvalue *result = ir;
 
-      /* Apply implicit conversions (not the scalar constructor rules!) */
+      /* Apply implicit conversions (not the scalar constructor rules!). See
+       * the spec quote above. */
       if (constructor_type->element_type()->is_float()) {
 	 const glsl_type *desired_type =
 	    glsl_type::get_instance(GLSL_TYPE_FLOAT,
 				    ir->type->vector_elements,
 				    ir->type->matrix_columns);
-	 result = convert_component(ir, desired_type);
+	 if (result->type->can_implicitly_convert_to(desired_type)) {
+	    /* Even though convert_component() implements the constructor
+	     * conversion rules (not the implicit conversion rules), its safe
+	     * to use it here because we already checked that the implicit
+	     * conversion is legal.
+	     */
+	    result = convert_component(ir, desired_type);
+	 }
       }
 
       if (result->type != constructor_type->element_type()) {
diff --git a/mesalib/src/glsl/glsl_types.cpp b/mesalib/src/glsl/glsl_types.cpp
index a5e21bbb9..c94aec0d2 100644
--- a/mesalib/src/glsl/glsl_types.cpp
+++ b/mesalib/src/glsl/glsl_types.cpp
@@ -523,3 +523,19 @@ glsl_type::component_slots() const
       return 0;
    }
 }
+
+bool
+glsl_type::can_implicitly_convert_to(const glsl_type *desired) const
+{
+   if (this == desired)
+      return true;
+
+   /* There is no conversion among matrix types. */
+   if (this->matrix_columns > 1 || desired->matrix_columns > 1)
+      return false;
+
+   /* int and uint can be converted to float. */
+   return desired->is_float()
+          && this->is_integer()
+          && this->vector_elements == desired->vector_elements;
+}
diff --git a/mesalib/src/glsl/glsl_types.h b/mesalib/src/glsl/glsl_types.h
index 87f57e7c7..048696693 100644
--- a/mesalib/src/glsl/glsl_types.h
+++ b/mesalib/src/glsl/glsl_types.h
@@ -224,6 +224,41 @@ struct glsl_type {
     */
    unsigned component_slots() const;
 
+   /**
+    * \brief Can this type be implicitly converted to another?
+    *
+    * \return True if the types are identical or if this type can be converted
+    *         to \c desired according to Section 4.1.10 of the GLSL spec.
+    *
+    * \verbatim
+    * From page 25 (31 of the pdf) of the GLSL 1.50 spec, Section 4.1.10
+    * Implicit Conversions:
+    *
+    *     In some situations, an expression and its type will be implicitly
+    *     converted to a different type. The following table shows all allowed
+    *     implicit conversions:
+    *
+    *     Type of expression | Can be implicitly converted to
+    *     --------------------------------------------------
+    *     int                  float
+    *     uint
+    *
+    *     ivec2                vec2
+    *     uvec2
+    *
+    *     ivec3                vec3
+    *     uvec3
+    *
+    *     ivec4                vec4
+    *     uvec4
+    *
+    *     There are no implicit array or structure conversions. For example,
+    *     an array of int cannot be implicitly converted to an array of float.
+    *     There are no implicit conversions between signed and unsigned
+    *     integers.
+    * \endverbatim
+    */
+   bool can_implicitly_convert_to(const glsl_type *desired) const;
 
    /**
     * Query whether or not a type is a scalar (non-vector and non-matrix).
diff --git a/mesalib/src/glsl/ir_function.cpp b/mesalib/src/glsl/ir_function.cpp
index 0f2f1a0ee..6cfc32cc2 100644
--- a/mesalib/src/glsl/ir_function.cpp
+++ b/mesalib/src/glsl/ir_function.cpp
@@ -24,73 +24,36 @@
 #include "glsl_types.h"
 #include "ir.h"
 
-int
-type_compare(const glsl_type *a, const glsl_type *b)
-{
-   /* If the types are the same, they trivially match.
-    */
-   if (a == b)
-      return 0;
-
-   switch (a->base_type) {
-   case GLSL_TYPE_UINT:
-   case GLSL_TYPE_INT:
-   case GLSL_TYPE_BOOL:
-      /* There is no implicit conversion to or from integer types or bool.
-       */
-      if ((a->is_integer() != b->is_integer())
-	  || (a->is_boolean() != b->is_boolean()))
-	 return -1;
-
-      /* FALLTHROUGH */
-
-   case GLSL_TYPE_FLOAT:
-      if ((a->vector_elements != b->vector_elements)
-	  || (a->matrix_columns != b->matrix_columns))
-	 return -1;
-
-      return 1;
-
-   case GLSL_TYPE_SAMPLER:
-   case GLSL_TYPE_STRUCT:
-      /* Samplers and structures must match exactly.
-       */
-      return -1;
-
-   case GLSL_TYPE_ARRAY:
-      if ((b->base_type != GLSL_TYPE_ARRAY)
-	  || (a->length != b->length))
-	 return -1;
-
-      /* From GLSL 1.50 spec, page 27 (page 33 of the PDF):
-       *    "There are no implicit array or structure conversions."
-       *
-       * If the comparison of the array element types detects that a conversion
-       * would be required, the array types do not match.
-       */
-      return (type_compare(a->fields.array, b->fields.array) == 0) ? 0 : -1;
-
-   case GLSL_TYPE_VOID:
-   case GLSL_TYPE_ERROR:
-   default:
-      /* These are all error conditions.  It is invalid for a parameter to
-       * a function to be declared as error, void, or a function.
-       */
-      return -1;
-   }
-
-   /* This point should be unreachable.
-    */
-   assert(0);
-}
-
+typedef enum {
+   PARAMETER_LIST_NO_MATCH,
+   PARAMETER_LIST_EXACT_MATCH,
+   PARAMETER_LIST_INEXACT_MATCH, /*< Match requires implicit conversion. */
+} parameter_list_match_t;
+
+/**
+ * \brief Check if two parameter lists match.
+ *
+ * \param list_a Parameters of the function definition.
+ * \param list_b Actual parameters passed to the function.
+ * \see matching_signature()
+ */
 
-static int
+/**
+ * \brief Check if two parameter lists match.
+ *
+ * \param list_a Parameters of the function definition.
+ * \param list_b Actual parameters passed to the function.
+ * \see matching_signature()
+ */
+static parameter_list_match_t
 parameter_lists_match(const exec_list *list_a, const exec_list *list_b)
 {
    const exec_node *node_a = list_a->head;
    const exec_node *node_b = list_b->head;
-   int total_score = 0;
+
+   /* This is set to true if there is an inexact match requiring an implicit
+    * conversion. */
+   bool inexact_match = false;
 
    for (/* empty */
 	; !node_a->is_tail_sentinel()
@@ -100,18 +63,17 @@ parameter_lists_match(const exec_list *list_a, const exec_list *list_b)
        * do not match.
        */
       if (node_b->is_tail_sentinel())
-	 return -1;
+	 return PARAMETER_LIST_NO_MATCH;
 
 
       const ir_variable *const param = (ir_variable *) node_a;
       const ir_instruction *const actual = (ir_instruction *) node_b;
 
-      /* Determine whether or not the types match.  If the types are an
-       * exact match, the match score is zero.  If the types don't match
-       * but the actual parameter can be coerced to the type of the declared
-       * parameter, the match score is one.
-       */
-      int score;
+      if (param->type == actual->type)
+	 continue;
+
+      /* Try to find an implicit conversion from actual to param. */
+      inexact_match = true;
       switch ((enum ir_variable_mode)(param->mode)) {
       case ir_var_auto:
       case ir_var_uniform:
@@ -121,15 +83,17 @@ parameter_lists_match(const exec_list *list_a, const exec_list *list_b)
 	  * as uniform.
 	  */
 	 assert(0);
-	 return -1;
+	 return PARAMETER_LIST_NO_MATCH;
 
       case ir_var_const_in:
       case ir_var_in:
-	 score = type_compare(param->type, actual->type);
+	 if (!actual->type->can_implicitly_convert_to(param->type))
+	    return PARAMETER_LIST_NO_MATCH;
 	 break;
 
       case ir_var_out:
-	 score = type_compare(actual->type, param->type);
+	 if (!param->type->can_implicitly_convert_to(actual->type))
+	    return PARAMETER_LIST_NO_MATCH;
 	 break;
 
       case ir_var_inout:
@@ -137,17 +101,12 @@ parameter_lists_match(const exec_list *list_a, const exec_list *list_b)
 	  * there is int -> float but no float -> int), inout parameters must
 	  * be exact matches.
 	  */
-	 score = (type_compare(actual->type, param->type) == 0) ? 0 : -1;
-	 break;
+	 return PARAMETER_LIST_NO_MATCH;
 
       default:
 	 assert(false);
+	 return PARAMETER_LIST_NO_MATCH;
       }
-
-      if (score < 0)
-	 return -1;
-
-      total_score += score;
    }
 
    /* If all of the parameters from the other parameter list have been
@@ -155,9 +114,12 @@ parameter_lists_match(const exec_list *list_a, const exec_list *list_b)
     * match.
     */
    if (!node_b->is_tail_sentinel())
-      return -1;
+      return PARAMETER_LIST_NO_MATCH;
 
-   return total_score;
+   if (inexact_match)
+      return PARAMETER_LIST_INEXACT_MATCH;
+   else
+      return PARAMETER_LIST_EXACT_MATCH;
 }
 
 
@@ -181,18 +143,20 @@ ir_function::matching_signature(const exec_list *actual_parameters)
       ir_function_signature *const sig =
 	 (ir_function_signature *) iter.get();
 
-      const int score = parameter_lists_match(& sig->parameters,
-					      actual_parameters);
-
-      /* If we found an exact match, simply return it */
-      if (score == 0)
+      switch (parameter_lists_match(& sig->parameters, actual_parameters)) {
+      case PARAMETER_LIST_EXACT_MATCH:
 	 return sig;
-
-      if (score > 0) {
+      case PARAMETER_LIST_INEXACT_MATCH:
 	 if (match == NULL)
 	    match = sig;
 	 else
 	    multiple_inexact_matches = true;
+	 continue;
+      case PARAMETER_LIST_NO_MATCH:
+	 continue;
+      default:
+	 assert(false);
+	 return NULL;
       }
    }