c: Add C API for builtin stage IO reflection.

CMakeLists.txt

@@ -332,7 +332,7 @@ if (SPIRV_CROSS_STATIC)
 endif()
 
 set(spirv-cross-abi-major 0)
-set(spirv-cross-abi-minor 46)
+set(spirv-cross-abi-minor 47)
 set(spirv-cross-abi-patch 0)
 
 if (SPIRV_CROSS_SHARED)

spirv_cross.hpp

@@ -70,6 +70,7 @@ struct BuiltInResource
 
 	// This is the actual value type of the builtin.
 	// Typically float4, float, array<float, N> for the gl_PerVertex builtins.
+	// If the builtin is a control point, the control point array type will be stripped away here as appropriate.
 	TypeID value_type_id;
 
 	// This refers to the base resource which contains the builtin.

spirv_cross_c.cpp

@@ -197,8 +197,11 @@ struct spvc_resources_s : ScratchMemoryAllocation
 	SmallVector<spvc_reflected_resource> separate_images;
 	SmallVector<spvc_reflected_resource> separate_samplers;
 	SmallVector<spvc_reflected_resource> acceleration_structures;
+	SmallVector<spvc_reflected_builtin_resource> builtin_inputs;
+	SmallVector<spvc_reflected_builtin_resource> builtin_outputs;
 
 	bool copy_resources(SmallVector<spvc_reflected_resource> &outputs, const SmallVector<Resource> &inputs);
+	bool copy_resources(SmallVector<spvc_reflected_builtin_resource> &outputs, const SmallVector<BuiltInResource> &inputs);
 	bool copy_resources(const ShaderResources &resources);
 };
 
@@ -1589,6 +1592,30 @@ bool spvc_resources_s::copy_resources(SmallVector<spvc_reflected_resource> &outp
 	return true;
 }
 
+bool spvc_resources_s::copy_resources(SmallVector<spvc_reflected_builtin_resource> &outputs,
+                                      const SmallVector<BuiltInResource> &inputs)
+{
+	for (auto &i : inputs)
+	{
+		spvc_reflected_builtin_resource br;
+
+		br.value_type_id = i.value_type_id;
+		br.builtin = SpvBuiltIn(i.builtin);
+
+		auto &r = br.resource;
+		r.base_type_id = i.resource.base_type_id;
+		r.type_id = i.resource.type_id;
+		r.id = i.resource.id;
+		r.name = context->allocate_name(i.resource.name);
+		if (!r.name)
+			return false;
+
+		outputs.push_back(br);
+	}
+
+	return true;
+}
+
 bool spvc_resources_s::copy_resources(const ShaderResources &resources)
 {
 	if (!copy_resources(uniform_buffers, resources.uniform_buffers))
@@ -1615,6 +1642,10 @@ bool spvc_resources_s::copy_resources(const ShaderResources &resources)
 		return false;
 	if (!copy_resources(acceleration_structures, resources.acceleration_structures))
 		return false;
+	if (!copy_resources(builtin_inputs, resources.builtin_inputs))
+		return false;
+	if (!copy_resources(builtin_outputs, resources.builtin_outputs))
+		return false;
 
 	return true;
 }
@@ -1773,6 +1804,37 @@ spvc_result spvc_resources_get_resource_list_for_type(spvc_resources resources,
 	return SPVC_SUCCESS;
 }
 
+spvc_result spvc_resources_get_builtin_resource_list_for_type(
+		spvc_resources resources, spvc_builtin_resource_type type,
+		const spvc_reflected_builtin_resource **resource_list,
+		size_t *resource_size)
+{
+	const SmallVector<spvc_reflected_builtin_resource> *list = nullptr;
+	switch (type)
+	{
+	case SPVC_BUILTIN_RESOURCE_TYPE_STAGE_INPUT:
+		list = &resources->builtin_inputs;
+		break;
+
+	case SPVC_BUILTIN_RESOURCE_TYPE_STAGE_OUTPUT:
+		list = &resources->builtin_outputs;
+		break;
+
+	default:
+		break;
+	}
+
+	if (!list)
+	{
+		resources->context->report_error("Invalid argument.");
+		return SPVC_ERROR_INVALID_ARGUMENT;
+	}
+
+	*resource_size = list->size();
+	*resource_list = list->data();
+	return SPVC_SUCCESS;
+}
+
 void spvc_compiler_set_decoration(spvc_compiler compiler, SpvId id, SpvDecoration decoration, unsigned argument)
 {
 	compiler->compiler->set_decoration(id, static_cast<spv::Decoration>(decoration), argument);

spirv_cross_c.h

@@ -40,7 +40,7 @@ extern "C" {
 /* Bumped if ABI or API breaks backwards compatibility. */
 #define SPVC_C_API_VERSION_MAJOR 0
 /* Bumped if APIs or enumerations are added in a backwards compatible way. */
-#define SPVC_C_API_VERSION_MINOR 46
+#define SPVC_C_API_VERSION_MINOR 47
 /* Bumped if internal implementation details change. */
 #define SPVC_C_API_VERSION_PATCH 0
 
@@ -99,6 +99,13 @@ typedef struct spvc_reflected_resource
 	const char *name;
 } spvc_reflected_resource;
 
+typedef struct spvc_reflected_builtin_resource
+{
+	SpvBuiltIn builtin;
+	spvc_type_id value_type_id;
+	spvc_reflected_resource resource;
+} spvc_reflected_builtin_resource;
+
 /* See C++ API. */
 typedef struct spvc_entry_point
 {
@@ -221,6 +228,14 @@ typedef enum spvc_resource_type
 	SPVC_RESOURCE_TYPE_INT_MAX = 0x7fffffff
 } spvc_resource_type;
 
+typedef enum spvc_builtin_resource_type
+{
+	SPVC_BUILTIN_RESOURCE_TYPE_UNKNOWN = 0,
+	SPVC_BUILTIN_RESOURCE_TYPE_STAGE_INPUT = 1,
+	SPVC_BUILTIN_RESOURCE_TYPE_STAGE_OUTPUT = 2,
+	SPVC_BUILTIN_RESOURCE_TYPE_INT_MAX = 0x7fffffff
+} spvc_builtin_resource_type;
+
 /* Maps to spirv_cross::SPIRType::BaseType. */
 typedef enum spvc_basetype
 {
@@ -809,6 +824,11 @@ SPVC_PUBLIC_API spvc_result spvc_resources_get_resource_list_for_type(spvc_resou
                                                                       const spvc_reflected_resource **resource_list,
                                                                       size_t *resource_size);
 
+SPVC_PUBLIC_API spvc_result spvc_resources_get_builtin_resource_list_for_type(
+		spvc_resources resources, spvc_builtin_resource_type type,
+		const spvc_reflected_builtin_resource **resource_list,
+		size_t *resource_size);
+
 /*
  * Decorations.
  * Maps to C++ API.