Add type description and default value to specialization constants

Author: jjyyxx

spirv_reflect.c

@@ -225,6 +225,7 @@ typedef struct SpvReflectPrvParser {
   uint32_t                        type_count;
   uint32_t                        descriptor_count;
   uint32_t                        push_constant_count;
+  uint32_t                        spec_constant_count;
 
   SpvReflectTypeDescription*      physical_pointer_check[MAX_RECURSIVE_PHYSICAL_POINTER_CHECK];
   uint32_t                        physical_pointer_count;
@@ -1420,7 +1421,7 @@ static bool UserTypeMatches(const char* user_type, const char* pattern) {
   return false;
 }
 
-static SpvReflectResult ParseDecorations(SpvReflectPrvParser* p_parser, SpvReflectShaderModule* p_module) {
+static SpvReflectResult ParseDecorations(SpvReflectPrvParser* p_parser) {
   uint32_t spec_constant_count = 0;
   for (uint32_t i = 0; i < p_parser->node_count; ++i) {
     SpvReflectPrvNode* p_node = &(p_parser->nodes[i]);
@@ -1722,31 +1723,7 @@ static SpvReflectResult ParseDecorations(SpvReflectPrvParser* p_parser, SpvRefle
     }
   }
 
-  if (spec_constant_count > 0) {
-    p_module->spec_constants = (SpvReflectSpecializationConstant*)calloc(spec_constant_count, sizeof(*p_module->spec_constants));
-    if (IsNull(p_module->spec_constants)) {
-      return SPV_REFLECT_RESULT_ERROR_ALLOC_FAILED;
-    }
-  }
-  for (uint32_t i = 0; i < p_parser->node_count; ++i) {
-    SpvReflectPrvNode* p_node = &(p_parser->nodes[i]);
-    if (p_node->op == SpvOpDecorate) {
-      uint32_t decoration = (uint32_t)INVALID_VALUE;
-      CHECKED_READU32(p_parser, p_node->word_offset + 2, decoration);
-      if (decoration == SpvDecorationSpecId) {
-        const uint32_t count = p_module->spec_constant_count;
-        CHECKED_READU32(p_parser, p_node->word_offset + 1, p_module->spec_constants[count].spirv_id);
-        CHECKED_READU32(p_parser, p_node->word_offset + 3, p_module->spec_constants[count].constant_id);
-        // If being used for a OpSpecConstantComposite (ex. LocalSizeId), there won't be a name
-        SpvReflectPrvNode* target_node = FindNode(p_parser, p_module->spec_constants[count].spirv_id);
-        if (IsNotNull(target_node)) {
-          p_module->spec_constants[count].name = target_node->name;
-        }
-        p_module->spec_constant_count++;
-      }
-    }
-  }
-
+  p_parser->spec_constant_count = spec_constant_count;
   return SPV_REFLECT_RESULT_SUCCESS;
 }
 
@@ -4055,6 +4032,63 @@ static SpvReflectResult ParsePushConstantBlocks(SpvReflectPrvParser* p_parser, S
   return SPV_REFLECT_RESULT_SUCCESS;
 }
 
+static SpvReflectResult ParseSpecConstants(SpvReflectPrvParser* p_parser, SpvReflectShaderModule* p_module) {
+  if (p_parser->spec_constant_count > 0) {
+    p_module->spec_constants = (SpvReflectSpecializationConstant*)calloc(p_parser->spec_constant_count, sizeof(*p_module->spec_constants));
+    if (IsNull(p_module->spec_constants)) {
+      return SPV_REFLECT_RESULT_ERROR_ALLOC_FAILED;
+    }
+  } else {
+    return SPV_REFLECT_RESULT_SUCCESS;
+  }
+  for (uint32_t i = 0; i < p_parser->node_count; ++i) {
+    SpvReflectPrvNode* p_node = &(p_parser->nodes[i]);
+    if (p_node->op == SpvOpDecorate) {
+      uint32_t decoration = (uint32_t)INVALID_VALUE;
+      CHECKED_READU32(p_parser, p_node->word_offset + 2, decoration);
+      if (decoration == SpvDecorationSpecId) {
+        SpvReflectSpecializationConstant* p_spec_constant = &(p_module->spec_constants[p_module->spec_constant_count]);
+        CHECKED_READU32(p_parser, p_node->word_offset + 1, p_spec_constant->spirv_id);
+        CHECKED_READU32(p_parser, p_node->word_offset + 3, p_spec_constant->constant_id);
+        SpvReflectPrvNode* target_node = FindNode(p_parser, p_spec_constant->spirv_id);
+        if (IsNotNull(target_node)) {
+          // If being used for a OpSpecConstantComposite (ex. LocalSizeId), there won't be a name
+          p_spec_constant->name = target_node->name;
+
+          // During external specialization, Boolean values are true if non-zero and false if zero.
+          static uint32_t true_value = 1;
+          static uint32_t false_value = 0;
+          switch (target_node->op) {
+            default:
+              // Unexpected, since Spec states:
+              //   (SpecId) Apply only to a scalar specialization constant
+              SPV_REFLECT_ASSERT(false);
+              return SPV_REFLECT_RESULT_ERROR_SPIRV_INVALID_INSTRUCTION;
+            case SpvOpSpecConstantTrue:
+              p_spec_constant->default_value_size = sizeof(uint32_t);
+              p_spec_constant->default_value = &true_value;
+              break;
+            case SpvOpSpecConstantFalse:
+              p_spec_constant->default_value_size = sizeof(uint32_t);
+              p_spec_constant->default_value = &false_value;
+              break;
+            case SpvOpSpecConstant:
+              p_spec_constant->default_value_size = (target_node->word_count - 3) * sizeof(uint32_t);
+              p_spec_constant->default_value = p_parser->spirv_code + target_node->word_offset + 3;
+              break;
+          }
+          p_spec_constant->type_description = FindType(p_module, target_node->result_type_id);
+        } else {
+          // Decoration target not found
+          return SPV_REFLECT_RESULT_ERROR_SPIRV_INVALID_ID_REFERENCE;
+        }
+        p_module->spec_constant_count++;
+      }
+    }
+  }
+  return SPV_REFLECT_RESULT_SUCCESS;
+}
+
 static int SortCompareDescriptorSet(const void* a, const void* b) {
   const SpvReflectDescriptorSet* p_elem_a = (const SpvReflectDescriptorSet*)a;
   const SpvReflectDescriptorSet* p_elem_b = (const SpvReflectDescriptorSet*)b;
@@ -4307,7 +4341,7 @@ static SpvReflectResult CreateShaderModule(uint32_t flags, size_t size, const vo
     SPV_REFLECT_ASSERT(result == SPV_REFLECT_RESULT_SUCCESS);
   }
   if (result == SPV_REFLECT_RESULT_SUCCESS) {
-    result = ParseDecorations(&parser, p_module);
+    result = ParseDecorations(&parser);
     SPV_REFLECT_ASSERT(result == SPV_REFLECT_RESULT_SUCCESS);
   }
 
@@ -4348,6 +4382,10 @@ static SpvReflectResult CreateShaderModule(uint32_t flags, size_t size, const vo
     result = ParsePushConstantBlocks(&parser, p_module);
     SPV_REFLECT_ASSERT(result == SPV_REFLECT_RESULT_SUCCESS);
   }
+  if (result == SPV_REFLECT_RESULT_SUCCESS) {
+    result = ParseSpecConstants(&parser, p_module);
+    SPV_REFLECT_ASSERT(result == SPV_REFLECT_RESULT_SUCCESS);
+  }
   if (result == SPV_REFLECT_RESULT_SUCCESS) {
     result = ParseEntryPoints(&parser, p_module);
     SPV_REFLECT_ASSERT(result == SPV_REFLECT_RESULT_SUCCESS);

spirv_reflect.h

@@ -580,6 +580,21 @@ typedef struct SpvReflectSpecializationConstant {
   uint32_t spirv_id;
   uint32_t constant_id;
   const char* name;
+  SpvReflectTypeDescription* type_description;
+
+  // Size of the default value in bytes (always a multiple of 4).
+  // Will be 4 for 8/16/32-bit constants and 8 for 64-bit constants.
+  uint32_t default_value_size;
+
+  // Pointer to the raw default value data.  
+  // The interpretation of this data depends on type_description->op:  
+  // - SpvOpSpecConstantTrue:  size = 4, data = uint32_t(1)  
+  // - SpvOpSpecConstantFalse: size = 4, data = uint32_t(0)  
+  // - SpvOpSpecConstant:      data contains the bit pattern of the default value  
+  //   * The type will be a scalar integer or float.
+  //   * Types 32 bits wide or smaller take one word.  
+  //   * Larger types take multiple words, with low-order words appearing first.  
+  void* default_value;  
 } SpvReflectSpecializationConstant;
 
 /*! @struct SpvReflectShaderModule