Fix several ubsan reported misaligned accesses

These misaligned accesses are shown in all of our CI hooks. It turned
out to not be difficult to fix.

It is likely that this will improve performance for aarch64.

Author: hpvb

drivers/vulkan/rendering_device_driver_vulkan.cpp

@@ -3441,7 +3441,7 @@ Vector<uint8_t> RenderingDeviceDriverVulkan::shader_compile_binary_from_spirv(Ve
 
 	binary_data.shader_name_len = shader_name_utf.length();
 
-	uint32_t total_size = sizeof(uint32_t) * 3; // Header + version + main datasize;.
+	uint32_t total_size = sizeof(uint32_t) * 4; // Header + version + pad + main datasize;.
 	total_size += sizeof(ShaderBinary::Data);
 
 	total_size += STEPIFY(binary_data.shader_name_len, 4);
@@ -3470,6 +3470,8 @@ Vector<uint8_t> RenderingDeviceDriverVulkan::shader_compile_binary_from_spirv(Ve
 		offset += sizeof(uint32_t);
 		encode_uint32(sizeof(ShaderBinary::Data), binptr + offset);
 		offset += sizeof(uint32_t);
+		encode_uint32(0, binptr + offset); // Pad to align ShaderBinary::Data to 8 bytes.
+		offset += sizeof(uint32_t);
 		memcpy(binptr + offset, &binary_data, sizeof(ShaderBinary::Data));
 		offset += sizeof(ShaderBinary::Data);
 
@@ -3528,15 +3530,16 @@ RDD::ShaderID RenderingDeviceDriverVulkan::shader_create_from_bytecode(const Vec
 	uint32_t read_offset = 0;
 
 	// Consistency check.
-	ERR_FAIL_COND_V(binsize < sizeof(uint32_t) * 3 + sizeof(ShaderBinary::Data), ShaderID());
+	ERR_FAIL_COND_V(binsize < sizeof(uint32_t) * 4 + sizeof(ShaderBinary::Data), ShaderID());
 	ERR_FAIL_COND_V(binptr[0] != 'G' || binptr[1] != 'S' || binptr[2] != 'B' || binptr[3] != 'D', ShaderID());
 
 	uint32_t bin_version = decode_uint32(binptr + 4);
 	ERR_FAIL_COND_V(bin_version != ShaderBinary::VERSION, ShaderID());
 
 	uint32_t bin_data_size = decode_uint32(binptr + 8);
 
-	const ShaderBinary::Data &binary_data = *(reinterpret_cast<const ShaderBinary::Data *>(binptr + 12));
+	// 16, not 12, to skip alignment padding.
+	const ShaderBinary::Data &binary_data = *(reinterpret_cast<const ShaderBinary::Data *>(binptr + 16));
 
 	r_shader_desc.push_constant_size = binary_data.push_constant_size;
 	shader_info.vk_push_constant_stages = binary_data.vk_push_constant_stages_mask;
@@ -3549,7 +3552,7 @@ RDD::ShaderID RenderingDeviceDriverVulkan::shader_create_from_bytecode(const Vec
 	r_shader_desc.compute_local_size[1] = binary_data.compute_local_size[1];
 	r_shader_desc.compute_local_size[2] = binary_data.compute_local_size[2];
 
-	read_offset += sizeof(uint32_t) * 3 + bin_data_size;
+	read_offset += sizeof(uint32_t) * 4 + bin_data_size;
 
 	if (binary_data.shader_name_len) {
 		r_name.parse_utf8((const char *)(binptr + read_offset), binary_data.shader_name_len);

drivers/vulkan/rendering_device_driver_vulkan.h

@@ -405,7 +405,8 @@ class RenderingDeviceDriverVulkan : public RenderingDeviceDriver {
 		// Version 2: Added shader name.
 		// Version 3: Added writable.
 		// Version 4: 64-bit vertex input mask.
-		static const uint32_t VERSION = 4;
+		// Version 5: Add 4 bytes padding to align the Data struct after the change in version 4.
+		static const uint32_t VERSION = 5;
 
 		struct DataBinding {
 			uint32_t type = 0;

servers/rendering/rendering_device_graph.cpp

@@ -228,6 +228,7 @@ int32_t RenderingDeviceGraph::_add_to_write_list(int32_t p_command_index, Rect2i
 
 RenderingDeviceGraph::RecordedCommand *RenderingDeviceGraph::_allocate_command(uint32_t p_command_size, int32_t &r_command_index) {
 	uint32_t command_data_offset = command_data.size();
+	command_data_offset = STEPIFY(command_data_offset, 8);
 	command_data_offsets.push_back(command_data_offset);
 	command_data.resize(command_data_offset + p_command_size);
 	r_command_index = command_count++;