glsl: Add convenience function get_sampler_instance

This is similar to the existing functions get_instance,
get_array_instance, etc. for getting a type singleton. The new
get_sampler_instance() function will be used by the upcoming shader
cache.

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>

src/glsl/glsl_types.cpp

@@ -474,6 +474,117 @@ glsl_type::get_instance(unsigned base_type, unsigned rows, unsigned columns)
    return error_type;
 }
 
+const glsl_type *
+glsl_type::get_sampler_instance(enum glsl_sampler_dim dim,
+                                bool shadow,
+                                bool array,
+                                glsl_base_type type)
+{
+   switch (type) {
+   case GLSL_TYPE_FLOAT:
+      switch (dim) {
+      case GLSL_SAMPLER_DIM_1D:
+         if (shadow)
+            return (array ? sampler1DArrayShadow_type : sampler1DShadow_type);
+         else
+            return (array ? sampler1DArray_type : sampler1D_type);
+      case GLSL_SAMPLER_DIM_2D:
+         if (shadow)
+            return (array ? sampler2DArrayShadow_type : sampler2DShadow_type);
+         else
+            return (array ? sampler2DArray_type : sampler2D_type);
+      case GLSL_SAMPLER_DIM_3D:
+         if (shadow || array)
+            return error_type;
+         else
+            return sampler3D_type;
+      case GLSL_SAMPLER_DIM_CUBE:
+         if (shadow)
+            return (array ? samplerCubeArrayShadow_type : samplerCubeShadow_type);
+         else
+            return (array ? samplerCubeArray_type : samplerCube_type);
+      case GLSL_SAMPLER_DIM_RECT:
+         if (array)
+            return error_type;
+         if (shadow)
+            return sampler2DRectShadow_type;
+         else
+            return sampler2DRect_type;
+      case GLSL_SAMPLER_DIM_BUF:
+         if (shadow || array)
+            return error_type;
+         else
+            return samplerBuffer_type;
+      case GLSL_SAMPLER_DIM_MS:
+         if (shadow)
+            return error_type;
+         return (array ? sampler2DMSArray_type : sampler2DMS_type);
+      case GLSL_SAMPLER_DIM_EXTERNAL:
+         if (shadow || array)
+            return error_type;
+         else
+            return samplerExternalOES_type;
+      }
+   case GLSL_TYPE_INT:
+      if (shadow)
+         return error_type;
+      switch (dim) {
+      case GLSL_SAMPLER_DIM_1D:
+         return (array ? isampler1DArray_type : isampler1D_type);
+      case GLSL_SAMPLER_DIM_2D:
+         return (array ? isampler2DArray_type : isampler2D_type);
+      case GLSL_SAMPLER_DIM_3D:
+         if (array)
+            return error_type;
+         return isampler3D_type;
+      case GLSL_SAMPLER_DIM_CUBE:
+         return (array ? isamplerCubeArray_type : isamplerCube_type);
+      case GLSL_SAMPLER_DIM_RECT:
+         if (array)
+            return error_type;
+         return isampler2DRect_type;
+      case GLSL_SAMPLER_DIM_BUF:
+         if (array)
+            return error_type;
+         return isamplerBuffer_type;
+      case GLSL_SAMPLER_DIM_MS:
+         return (array ? isampler2DMSArray_type : isampler2DMS_type);
+      case GLSL_SAMPLER_DIM_EXTERNAL:
+         return error_type;
+      }
+   case GLSL_TYPE_UINT:
+      if (shadow)
+         return error_type;
+      switch (dim) {
+      case GLSL_SAMPLER_DIM_1D:
+         return (array ? usampler1DArray_type : usampler1D_type);
+      case GLSL_SAMPLER_DIM_2D:
+         return (array ? usampler2DArray_type : usampler2D_type);
+      case GLSL_SAMPLER_DIM_3D:
+         if (array)
+            return error_type;
+         return usampler3D_type;
+      case GLSL_SAMPLER_DIM_CUBE:
+         return (array ? usamplerCubeArray_type : usamplerCube_type);
+      case GLSL_SAMPLER_DIM_RECT:
+         if (array)
+            return error_type;
+         return usampler2DRect_type;
+      case GLSL_SAMPLER_DIM_BUF:
+         if (array)
+            return error_type;
+         return usamplerBuffer_type;
+      case GLSL_SAMPLER_DIM_MS:
+         return (array ? usampler2DMSArray_type : usampler2DMS_type);
+      case GLSL_SAMPLER_DIM_EXTERNAL:
+         return error_type;
+      }
+   default:
+      return error_type;
+   }
+
+   unreachable("switch statement above should be complete");
+}
 
 const glsl_type *
 glsl_type::get_array_instance(const glsl_type *base, unsigned array_size)

src/glsl/glsl_types.h

@@ -243,6 +243,15 @@ struct glsl_type {
    static const glsl_type *get_instance(unsigned base_type, unsigned rows,
 					unsigned columns);
 
+   /**
+    * Get the instance of a sampler type
+    */
+   static const glsl_type *get_sampler_instance(enum glsl_sampler_dim dim,
+                                                bool shadow,
+                                                bool array,
+                                                glsl_base_type type);
+
+
    /**
     * Get the instance of an array type
     */