Make shader binary alignment handling simpler and more robust

Bonus:
Also simplified the rounding to block size in image size calculations.

drivers/d3d12/rendering_device_driver_d3d12.cpp

@@ -3246,10 +3246,7 @@ Vector<uint8_t> RenderingDeviceDriverD3D12::shader_compile_binary_from_spirv(Vec
 		compressed_stages.push_back(zstd);
 
 		uint32_t s = compressed_stages[i].size();
-		if (s % 4 != 0) {
-			s += 4 - (s % 4);
-		}
-		stages_binary_size += s;
+		stages_binary_size += STEPIFY(s, 4);
 	}
 
 	CharString shader_name_utf = p_shader_name.utf8();
@@ -3259,10 +3256,7 @@ Vector<uint8_t> RenderingDeviceDriverD3D12::shader_compile_binary_from_spirv(Vec
 	uint32_t total_size = sizeof(uint32_t) * 3; // Header + version + main datasize;.
 	total_size += sizeof(ShaderBinary::Data);
 
-	total_size += binary_data.shader_name_len;
-	if ((binary_data.shader_name_len % 4) != 0) { // Alignment rules are really strange.
-		total_size += 4 - (binary_data.shader_name_len % 4);
-	}
+	total_size += STEPIFY(binary_data.shader_name_len, 4);
 
 	for (int i = 0; i < sets_bindings.size(); i++) {
 		total_size += sizeof(uint32_t);
@@ -3294,13 +3288,17 @@ Vector<uint8_t> RenderingDeviceDriverD3D12::shader_compile_binary_from_spirv(Vec
 		memcpy(binptr + offset, &binary_data, sizeof(ShaderBinary::Data));
 		offset += sizeof(ShaderBinary::Data);
 
+#define ADVANCE_OFFSET_WITH_ALIGNMENT(m_bytes)                         \
+	{                                                                  \
+		offset += m_bytes;                                             \
+		uint32_t padding = STEPIFY(m_bytes, 4) - m_bytes;              \
+		memset(binptr + offset, 0, padding); /* Avoid garbage data. */ \
+		offset += padding;                                             \
+	}
+
 		if (binary_data.shader_name_len > 0) {
 			memcpy(binptr + offset, shader_name_utf.ptr(), binary_data.shader_name_len);
-			offset += binary_data.shader_name_len;
-
-			if ((binary_data.shader_name_len % 4) != 0) { // Alignment rules are really strange.
-				offset += 4 - (binary_data.shader_name_len % 4);
-			}
+			ADVANCE_OFFSET_WITH_ALIGNMENT(binary_data.shader_name_len);
 		}
 
 		for (int i = 0; i < sets_bindings.size(); i++) {
@@ -3326,14 +3324,7 @@ Vector<uint8_t> RenderingDeviceDriverD3D12::shader_compile_binary_from_spirv(Vec
 			encode_uint32(zstd_size[i], binptr + offset);
 			offset += sizeof(uint32_t);
 			memcpy(binptr + offset, compressed_stages[i].ptr(), compressed_stages[i].size());
-
-			uint32_t s = compressed_stages[i].size();
-
-			if (s % 4 != 0) {
-				s += 4 - (s % 4);
-			}
-
-			offset += s;
+			ADVANCE_OFFSET_WITH_ALIGNMENT(compressed_stages[i].size());
 		}
 
 		memcpy(binptr + offset, root_sig_blob->GetBufferPointer(), root_sig_blob->GetBufferSize());
@@ -3382,10 +3373,7 @@ RDD::ShaderID RenderingDeviceDriverD3D12::shader_create_from_bytecode(const Vect
 
 	if (binary_data.shader_name_len) {
 		r_name.parse_utf8((const char *)(binptr + read_offset), binary_data.shader_name_len);
-		read_offset += binary_data.shader_name_len;
-		if ((binary_data.shader_name_len % 4) != 0) { // Alignment rules are really strange.
-			read_offset += 4 - (binary_data.shader_name_len % 4);
-		}
+		read_offset += STEPIFY(binary_data.shader_name_len, 4);
 	}
 
 	r_shader_desc.uniform_sets.resize(binary_data.set_count);
@@ -3458,6 +3446,7 @@ RDD::ShaderID RenderingDeviceDriverD3D12::shader_create_from_bytecode(const Vect
 
 	for (uint32_t i = 0; i < binary_data.stage_count; i++) {
 		ERR_FAIL_COND_V(read_offset + sizeof(uint32_t) * 3 >= binsize, ShaderID());
+
 		uint32_t stage = decode_uint32(binptr + read_offset);
 		read_offset += sizeof(uint32_t);
 		uint32_t dxil_size = decode_uint32(binptr + read_offset);
@@ -3472,13 +3461,9 @@ RDD::ShaderID RenderingDeviceDriverD3D12::shader_create_from_bytecode(const Vect
 		ERR_FAIL_COND_V(dec_dxil_size != (int32_t)dxil_size, ShaderID());
 		shader_info_in.stages_bytecode[ShaderStage(stage)] = dxil;
 
-		if (zstd_size % 4 != 0) {
-			zstd_size += 4 - (zstd_size % 4);
-		}
-
-		ERR_FAIL_COND_V(read_offset + zstd_size > binsize, ShaderID());
-
+		zstd_size = STEPIFY(zstd_size, 4);
 		read_offset += zstd_size;
+		ERR_FAIL_COND_V(read_offset > binsize, ShaderID());
 	}
 
 	const uint8_t *root_sig_data_ptr = binptr + read_offset;

drivers/vulkan/rendering_device_driver_vulkan.cpp

@@ -2957,10 +2957,7 @@ Vector<uint8_t> RenderingDeviceDriverVulkan::shader_compile_binary_from_spirv(Ve
 			}
 		}
 		uint32_t s = compressed_stages[i].size();
-		if (s % 4 != 0) {
-			s += 4 - (s % 4);
-		}
-		stages_binary_size += s;
+		stages_binary_size += STEPIFY(s, 4);
 	}
 
 	binary_data.specialization_constants_count = specialization_constants.size();
@@ -2974,11 +2971,7 @@ Vector<uint8_t> RenderingDeviceDriverVulkan::shader_compile_binary_from_spirv(Ve
 	uint32_t total_size = sizeof(uint32_t) * 3; // Header + version + main datasize;.
 	total_size += sizeof(ShaderBinary::Data);
 
-	total_size += binary_data.shader_name_len;
-
-	if ((binary_data.shader_name_len % 4) != 0) { // Alignment rules are really strange.
-		total_size += 4 - (binary_data.shader_name_len % 4);
-	}
+	total_size += STEPIFY(binary_data.shader_name_len, 4);
 
 	for (int i = 0; i < uniforms.size(); i++) {
 		total_size += sizeof(uint32_t);
@@ -3007,13 +3000,17 @@ Vector<uint8_t> RenderingDeviceDriverVulkan::shader_compile_binary_from_spirv(Ve
 		memcpy(binptr + offset, &binary_data, sizeof(ShaderBinary::Data));
 		offset += sizeof(ShaderBinary::Data);
 
+#define ADVANCE_OFFSET_WITH_ALIGNMENT(m_bytes)                         \
+	{                                                                  \
+		offset += m_bytes;                                             \
+		uint32_t padding = STEPIFY(m_bytes, 4) - m_bytes;              \
+		memset(binptr + offset, 0, padding); /* Avoid garbage data. */ \
+		offset += padding;                                             \
+	}
+
 		if (binary_data.shader_name_len > 0) {
 			memcpy(binptr + offset, shader_name_utf.ptr(), binary_data.shader_name_len);
-			offset += binary_data.shader_name_len;
-
-			if ((binary_data.shader_name_len % 4) != 0) { // Alignment rules are really strange.
-				offset += 4 - (binary_data.shader_name_len % 4);
-			}
+			ADVANCE_OFFSET_WITH_ALIGNMENT(binary_data.shader_name_len);
 		}
 
 		for (int i = 0; i < uniforms.size(); i++) {
@@ -3039,14 +3036,7 @@ Vector<uint8_t> RenderingDeviceDriverVulkan::shader_compile_binary_from_spirv(Ve
 			encode_uint32(zstd_size[i], binptr + offset);
 			offset += sizeof(uint32_t);
 			memcpy(binptr + offset, compressed_stages[i].ptr(), compressed_stages[i].size());
-
-			uint32_t s = compressed_stages[i].size();
-
-			if (s % 4 != 0) {
-				s += 4 - (s % 4);
-			}
-
-			offset += s;
+			ADVANCE_OFFSET_WITH_ALIGNMENT(compressed_stages[i].size());
 		}
 
 		DEV_ASSERT(offset == (uint32_t)ret.size());
@@ -3090,10 +3080,7 @@ RDD::ShaderID RenderingDeviceDriverVulkan::shader_create_from_bytecode(const Vec
 
 	if (binary_data.shader_name_len) {
 		r_name.parse_utf8((const char *)(binptr + read_offset), binary_data.shader_name_len);
-		read_offset += binary_data.shader_name_len;
-		if ((binary_data.shader_name_len % 4) != 0) { // Alignment rules are really strange.
-			read_offset += 4 - (binary_data.shader_name_len % 4);
-		}
+		read_offset += STEPIFY(binary_data.shader_name_len, 4);
 	}
 
 	Vector<Vector<VkDescriptorSetLayoutBinding>> vk_set_bindings;
@@ -3192,6 +3179,7 @@ RDD::ShaderID RenderingDeviceDriverVulkan::shader_create_from_bytecode(const Vec
 
 	for (uint32_t i = 0; i < binary_data.stage_count; i++) {
 		ERR_FAIL_COND_V(read_offset + sizeof(uint32_t) * 3 >= binsize, ShaderID());
+
 		uint32_t stage = decode_uint32(binptr + read_offset);
 		read_offset += sizeof(uint32_t);
 		uint32_t smolv_size = decode_uint32(binptr + read_offset);
@@ -3223,16 +3211,12 @@ RDD::ShaderID RenderingDeviceDriverVulkan::shader_create_from_bytecode(const Vec
 
 		r_shader_desc.stages.set(i, ShaderStage(stage));
 
-		if (buf_size % 4 != 0) {
-			buf_size += 4 - (buf_size % 4);
-		}
-
-		DEV_ASSERT(read_offset + buf_size <= binsize);
-
+		buf_size = STEPIFY(buf_size, 4);
 		read_offset += buf_size;
+		ERR_FAIL_COND_V(read_offset > binsize, ShaderID());
 	}
 
-	DEV_ASSERT(read_offset == binsize);
+	ERR_FAIL_COND_V(read_offset != binsize, ShaderID());
 
 	// Modules.
 

servers/rendering/rendering_device_commons.cpp

@@ -711,12 +711,13 @@ uint32_t RenderingDeviceCommons::get_image_format_required_size(DataFormat p_for
 
 	uint32_t pixel_size = get_image_format_pixel_size(p_format);
 	uint32_t pixel_rshift = get_compressed_image_format_pixel_rshift(p_format);
-	uint32_t blockw, blockh;
+	uint32_t blockw = 0;
+	uint32_t blockh = 0;
 	get_compressed_image_format_block_dimensions(p_format, blockw, blockh);
 
 	for (uint32_t i = 0; i < p_mipmaps; i++) {
-		uint32_t bw = w % blockw != 0 ? w + (blockw - w % blockw) : w;
-		uint32_t bh = h % blockh != 0 ? h + (blockh - h % blockh) : h;
+		uint32_t bw = STEPIFY(w, blockw);
+		uint32_t bh = STEPIFY(h, blockh);
 
 		uint32_t s = bw * bh;