nir/vtn: Convert constant samplers to variables with data

Reviewd-by: Jason Ekstrand <jason@jlekstrand.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5242>

src/compiler/nir/nir.h

@@ -545,6 +545,16 @@ typedef struct nir_variable {
             enum pipe_format format;
          } image;
 
+         struct {
+            /**
+             * For OpenCL inline samplers. See cl_sampler_addressing_mode and cl_sampler_filter_mode
+             */
+            unsigned is_inline_sampler : 1;
+            unsigned addressing_mode : 3;
+            unsigned normalized_coordinates : 1;
+            unsigned filter_mode : 1;
+         } sampler;
+
          struct {
             /**
              * Transform feedback buffer.

src/compiler/nir/nir_print.c

@@ -298,6 +298,29 @@ get_var_name(nir_variable *var, print_state *state)
    return name;
 }
 
+static const char *
+get_constant_sampler_addressing_mode(enum cl_sampler_addressing_mode mode)
+{
+   switch (mode) {
+   case SAMPLER_ADDRESSING_MODE_NONE: return "none";
+   case SAMPLER_ADDRESSING_MODE_CLAMP_TO_EDGE: return "clamp_to_edge";
+   case SAMPLER_ADDRESSING_MODE_CLAMP: return "clamp";
+   case SAMPLER_ADDRESSING_MODE_REPEAT: return "repeat";
+   case SAMPLER_ADDRESSING_MODE_REPEAT_MIRRORED: return "repeat_mirrored";
+   default: unreachable("Invalid addressing mode");
+   }
+}
+
+static const char *
+get_constant_sampler_filter_mode(enum cl_sampler_filter_mode mode)
+{
+   switch (mode) {
+   case SAMPLER_FILTER_MODE_NEAREST: return "nearest";
+   case SAMPLER_FILTER_MODE_LINEAR: return "linear";
+   default: unreachable("Invalid filter mode");
+   }
+}
+
 static void
 print_constant(nir_constant *c, const struct glsl_type *type, print_state *state)
 {
@@ -571,6 +594,12 @@ print_var_decl(nir_variable *var, print_state *state)
       print_constant(var->constant_initializer, var->type, state);
       fprintf(fp, " }");
    }
+   if (glsl_type_is_sampler(var->type) && var->data.sampler.is_inline_sampler) {
+      fprintf(fp, " = { %s, %s, %s }",
+              get_constant_sampler_addressing_mode(var->data.sampler.addressing_mode),
+              var->data.sampler.normalized_coordinates ? "true" : "false",
+              get_constant_sampler_filter_mode(var->data.sampler.filter_mode));
+   }
    if (var->pointer_initializer)
       fprintf(fp, " = &%s", get_var_name(var->pointer_initializer, state));
 

src/compiler/shader_enums.h

@@ -900,6 +900,23 @@ enum float_controls
    FLOAT_CONTROLS_ROUNDING_MODE_RTZ_FP64            = 0x4000,
 };
 
+/**
+* Enums to describe sampler properties used by OpenCL's inline constant samplers.
+* These values match the meanings described in the SPIR-V spec.
+*/
+enum cl_sampler_addressing_mode {
+   SAMPLER_ADDRESSING_MODE_NONE = 0,
+   SAMPLER_ADDRESSING_MODE_CLAMP_TO_EDGE = 1,
+   SAMPLER_ADDRESSING_MODE_CLAMP = 2,
+   SAMPLER_ADDRESSING_MODE_REPEAT = 3,
+   SAMPLER_ADDRESSING_MODE_REPEAT_MIRRORED = 4,
+};
+
+enum cl_sampler_filter_mode {
+   SAMPLER_FILTER_MODE_NEAREST = 0,
+   SAMPLER_FILTER_MODE_LINEAR = 1,
+};
+
 #ifdef __cplusplus
 } /* extern "C" */
 #endif

src/compiler/shader_info.h

@@ -58,6 +58,7 @@ struct spirv_supported_capabilities {
    bool integer_functions2;
    bool kernel;
    bool kernel_image;
+   bool literal_sampler;
    bool min_lod;
    bool multiview;
    bool physical_storage_buffer_address;

src/compiler/spirv/spirv_to_nir.c

@@ -2095,10 +2095,6 @@ vtn_handle_constant(struct vtn_builder *b, SpvOp opcode,
       val->constant = vtn_null_constant(b, val->type);
       break;
 
-   case SpvOpConstantSampler:
-      vtn_fail("OpConstantSampler requires Kernel Capability");
-      break;
-
    default:
       vtn_fail_with_opcode("Unhandled opcode", opcode);
    }
@@ -4237,11 +4233,14 @@ vtn_handle_preamble_instruction(struct vtn_builder *b, SpvOp opcode,
          spv_check_supported(kernel_image, cap);
          break;
 
+      case SpvCapabilityLiteralSampler:
+         spv_check_supported(literal_sampler, cap);
+         break;
+
       case SpvCapabilityImageReadWrite:
       case SpvCapabilityImageMipmap:
       case SpvCapabilityPipes:
       case SpvCapabilityDeviceEnqueue:
-      case SpvCapabilityLiteralSampler:
       case SpvCapabilityGenericPointer:
          vtn_warn("Unsupported OpenCL-style SPIR-V capability: %s",
                   spirv_capability_to_string(cap));
@@ -4885,7 +4884,6 @@ vtn_handle_variable_or_type_instruction(struct vtn_builder *b, SpvOp opcode,
    case SpvOpConstantFalse:
    case SpvOpConstant:
    case SpvOpConstantComposite:
-   case SpvOpConstantSampler:
    case SpvOpConstantNull:
    case SpvOpSpecConstantTrue:
    case SpvOpSpecConstantFalse:
@@ -4897,6 +4895,7 @@ vtn_handle_variable_or_type_instruction(struct vtn_builder *b, SpvOp opcode,
 
    case SpvOpUndef:
    case SpvOpVariable:
+   case SpvOpConstantSampler:
       vtn_handle_variables(b, opcode, w, count);
       break;
 

src/compiler/spirv/vtn_variables.c

@@ -2486,6 +2486,32 @@ vtn_handle_variables(struct vtn_builder *b, SpvOp opcode,
       break;
    }
 
+   case SpvOpConstantSampler: {
+      /* Synthesize a pointer-to-sampler type, create a variable of that type,
+       * and give the variable a constant initializer with the sampler params */
+      struct vtn_type *sampler_type = vtn_value(b, w[1], vtn_value_type_type)->type;
+      struct vtn_value *val = vtn_push_value(b, w[2], vtn_value_type_pointer);
+
+      struct vtn_type *ptr_type = rzalloc(b, struct vtn_type);
+      ptr_type = rzalloc(b, struct vtn_type);
+      ptr_type->base_type = vtn_base_type_pointer;
+      ptr_type->deref = sampler_type;
+      ptr_type->storage_class = SpvStorageClassUniform;
+
+      ptr_type->type = nir_address_format_to_glsl_type(
+         vtn_mode_to_address_format(b, vtn_variable_mode_function));
+
+      vtn_create_variable(b, val, ptr_type, ptr_type->storage_class, NULL, NULL);
+
+      nir_variable *nir_var = val->pointer->var->var;
+      nir_var->data.sampler.is_inline_sampler = true;
+      nir_var->data.sampler.addressing_mode = w[3];
+      nir_var->data.sampler.normalized_coordinates = w[4];
+      nir_var->data.sampler.filter_mode = w[5];
+
+      break;
+   }
+
    case SpvOpAccessChain:
    case SpvOpPtrAccessChain:
    case SpvOpInBoundsAccessChain: