What is Building Process?

The build process is a crucial aspect of software development, transforming source code into a fully functional application, library, or software product ready for deployment. This article delves into the various stages and best practices of the build process, from initial code writing to final delivery to the end user.

The build process, in the software development lifecycle, is the entire set of steps followed to transform the source code written by developers into a runnable application, library, or another type of software product. This process encompasses all stages from the moment the code is written to its delivery to the end user.

1- Writing Source Code

The first step in the software development process is writing the source code. This involves writing Swift code that defines the functionality of the application. The code written at this stage forms the foundational building blocks of the application.

2- Preprocessing

Before the compilation process begins, the preprocessing step is carried out. In this step, macros used in the source code are expanded, file inclusion directives (#import) are processed, and conditional compilation directives are evaluated. In Swift, this step is minimal because the language has limited preprocessor directives.

3- Compilation

The compilation stage involves translating the source code into machine language. This process consists of several sub-steps:

• Syntax Analysis

The compiler checks if the source code is written correctly. Syntax errors are detected and reported at this stage.

• Semantic Analysis

The compiler checks for logical errors in the code. Data types, variable scopes, and function calls are verified at this stage.

• Intermediate Code Generation

The source code is translated into an intermediate form that will later be converted to machine code. This intermediate code can be platform-independent.

• Optimization

Various optimizations are performed on the intermediate code to make it run more efficiently. For example, loop optimization or the elimination of unnecessary variables may be done.

• Machine Code Generation

After optimizations, the intermediate code is translated into machine code, which can be directly executed by the machine.

4- Linking

After the compilation stage, the linking process is performed. This step involves combining the compiled code with other libraries and modules. Linking can occur in two ways:

• Static Linking

All necessary libraries and dependencies are combined during the compilation stage, resulting in a single executable file. This method does not require the dependencies to be present at runtime.

• Dynamic Linking

The required libraries are loaded when the application is run. This method allows the application to be smaller in size and enables the sharing of libraries among different applications.

5- Debugging and Testing

In this stage, the application is tested, and potential errors are debugged. The tools and techniques used in this step include:

• Unit Tests

These tests check whether specific functions and methods in the code are working correctly.

• Integration Tests

These tests verify whether different modules work together correctly.

• User Acceptance Tests

These tests ensure that the application meets the end user’s requirements.

• Debugging Tools

In development environments like Xcode, debugging tools are used to step through the code, check variable values, and identify errors.

6- Optimization

The optimization stage involves making various improvements to the code to enhance the application’s performance. Some optimization techniques applied at this stage include:

• Code Inlining

Inlining small functions directly into the code instead of calling them.

• Dead Code Elimination

Removing unused or unnecessary code segments.

• Loop Optimizations

Making loops more efficient.

7- Distribution

In the final stage, the application is packaged and prepared for distribution. This step ensures that the application reaches the end user.

• Packaging

All components of the application are brought together and packaged in a suitable format for distribution.

• Code Signing

The code is signed to ensure the security and integrity of the application. This is particularly necessary for applications to be published on platforms like the App Store.

• Submission

The application is uploaded to the chosen distribution platform and undergoes review before being published.

The Importance of the Compilation Process

The compilation process is a critical process that directly influences the quality, performance, and reliability of software. Understanding this process helps developers produce faster, safer, and more efficient applications. Additionally, early detection and correction of errors significantly enhance the end-user experience.

Key Concepts in the Compilation Process

Build Signing

Ensures the security and integrity of your application. Code signing is necessary for distributing applications on the App Store and running them on physical devices.

Build Signing Process in Swift

When developing iOS applications with Swift, the build signing process is typically conducted using Xcode. Here are the basic steps of this process:

1. Developer Account and Certificates

• Apple Developer Account: You need an Apple developer account for signing and distributing applications.
• Certificates: You need to sign in with your developer account to create the necessary certificates. These certificates are used for digitally signing your application.

2. Profile and Certificate Creation

• Code Signing Certificate: A code signing certificate is created through the Apple Developer Portal.
• Provisioning Profile: A provisioning profile allowing your application to run on specific devices is created. This profile contains the necessary information for signing the application.

3. Configuring Settings in Xcode

• Project Settings: You can enter the code signing certificate and provisioning profile information by navigating to your project’s settings in Xcode.
• Automatic Signing: Xcode provides automatic signing feature to manage signing operations automatically. This feature automatically matches the code signing certificate and provisioning profile.

4. Signing the Application

• Build and Archive: When you compile your application using Xcode, Xcode automatically performs the signing process.
• Export: When your application is archived for uploading to the App Store or distributing to test devices, a signed version of the application is generated.

Steps in Build Signing

Certificate and Profile Creation: Necessary certificates and provisioning profiles are created in the Apple Developer Portal.

Xcode Settings: Code signing settings for the project are configured in Xcode.

Compilation and Signing: The application is compiled and signed.

Testing and Distribution: The signed application is uploaded to test devices or the App Store.

Build Settings

Build settings are configuration options that define how your project will be compiled. This includes compiler flags, optimization levels, and the SDK version to be used.

1. Basic Build Settings Categories

• Display Name: The name displayed on the device for the application.
• Bundle Identifier: The unique identifier of the application, defining it on the App Store and devices.
• Version: The version number of the application.
• Build Number: The build number of the application, incremented for each new build.

2. Info.plist

File Contains essential configuration information for the application, such as the app name, version info, permissions, etc.

3. Deployment Settings

• Deployment Target: Specifies the iOS versions on which the application will run.
• Supported Interface Orientations: Specifies the orientations in which the application will run.

4. Build Options

• Architectures: Specifies which processor architectures the application will run on (e.g., arm64).
• Build Active Architecture Only: Option to build only for the active architecture.

5. Code Signing

• Code Signing Identity: Specifies which code signing certificate will sign the application.
• Provisioning Profile: Specifies which provisioning profile will distribute the application.

6. Optimization Settings

• Optimization Level: Specifies how the code will be optimized during compilation (e.g., O0, O1, O2).
• Enable Bitcode: Specifies whether bitcode support will be enabled.

7. Linking

• Other Linker Flags: Additional flags passed to the linker.
• Dead Code Stripping: Specifies whether unused code will be stripped during compilation.

Build Phases

A build phase defines the steps in the compilation process for a target. Each build phase performs a specific task, such as compiling sources, linking libraries, and copying resources.

Standard Build Phases in Xcode

Some common build phases that are default in Xcode include:

1. Target Dependencies Purpose: This phase checks whether a target depends on another target. If it does, the dependent target is compiled first.

Usage: If your application uses a framework or another module, their dependencies need to be compiled.

2. Compile Sources Purpose: This phase compiles the Swift or Objective-C source files in the project.

Usage: It’s the stage where all your source code files are translated into machine code.

3. Link Binary with Libraries Purpose: This phase links the libraries and frameworks necessary for your application to run.

Usage: Used when adding external libraries or frameworks you want to use in your project.

4. Copy Bundle Resources Purpose: This phase copies the resource files (images, plist files, nib files, etc.) required for your application to run into the application bundle.

Usage: User interface, asset files, and other resource files of your application are copied at this stage.

5. Run Script Purpose: This phase is used to run custom scripts at specific points during the build process.

Usage: It can be used, for example, to process specific files, optimize resource files, or perform custom compilation tasks.

6. Headers Purpose: This phase manages the header files in the project, which is particularly important in C or Objective-C projects.

Usage: Ensures proper sharing of header files between libraries and other code components.

Managing Build Phases Adding or Editing Build Phases

Selecting Target in Project Navigator: In Xcode, select your target from the project navigator on the left.

Build Phases Tab: Go to the “Build Phases” tab in the settings of the selected target.

Adding a New Phase: Click the “+” button to add a new phase.

Build Rules

Build rules are the rules that determine how specific types of files are processed in Xcode projects. These rules define which compiler or processing tool these files will go through based on their file extension or type. In Swift projects, build rules provide flexibility for processing and including custom file types in the project.

Components of Build Rules

• File Patterns: Defines which types of files adhere to this rule. For example, a rule can be defined for files with the .swift extension.
• Compiler: Specifies which compiler or processing tool the files will go through. For example, Swift compiler (swiftc) or another custom tool can be specified.
• Output Files: Defines where and how the output of the processed file will be stored. This determines the file locations to be used in subsequent stages of the compilation process.

Using Build Rules in Xcode

In Xcode, you can add and customize custom compilation rules to your project using build rules. Here is the step-by-step process of creating build rules:

• Navigate to Project Settings in Xcode: Right-click on the project and select “Show Build Settings.”
• Open the Build Rules Tab: Find and open the “Build Rules” tab in the project settings menu.
• Adding a New Rule: Click the “+” button to add a new build rule. Specify File Patterns: Define file patterns for the new rule. For example, *.swift or *.customext.
• Select Compiler or Processing Tool: Choose the compiler or processing tool to be used for this file type. For example, swiftc for Swift files or a custom script.
• Define Output Files: Specify the output locations and filenames for the processed files.

Scheme

A scheme is a set of settings in Xcode projects that defines how you will compile and run the project by specifying a certain target, build configuration, and action. In Swift projects, schemes are used to manage and control different stages of the project development process.

Features of a Scheme

• Targets: Specifies which target will be compiled. A project can include multiple targets such as application, test, framework, etc.
• Configurations: Defines which configuration (e.g., Debug or Release) will be used for a specific scheme.
• Actions: Defines specific operations related to the project. For example, building, testing, running, profiling, analyzing, and archiving.

Scheme Components

• Build: Compiles the selected target with the specified configuration.
• Run: Runs the application on the simulator or a real device with the specified configuration.
• Test: Executes the test targets in the project.
• Profile: Runs tools for analyzing the performance of the application.
• Analyze: Analyzes the code and identifies potential errors and improvements.
• Archive: Archives the application for publishing or distribution purposes.

Using Schemes in Xcode

Schemes are managed through a dropdown menu located in the top left corner of the project window in Xcode. From this menu, you can select existing schemes or create new ones.

1. Creating a New Scheme Scheme

• Selector Menu: Click on the scheme selector menu in the top left corner of Xcode.
• Adding a New Scheme: Click on “Manage Schemes,” then click the “+” button to create a new scheme.
• Scheme Settings: Configure targets, configurations, and actions for the new scheme.

2. Editing an Existing Scheme Scheme

• Selector Menu: Click on the scheme selector menu in the top left corner of Xcode. Accessing
• Scheme Settings: Select the scheme you want to edit and click on the “Edit Scheme” option.
• Scheme Editing Window: In the opened window, adjust the settings for build, run, test, profile, analyze, and archive.

Target

It is a component of a project and represents a specific output. Each target can have its own build settings, build phases, and build rules configurations. For example, within the same project, an iOS application, a macOS application, and a test suite can be defined as different targets.

Properties of a Target

• Product Type: Defines the type of output that the target will produce. For example, application (app), dynamic library, framework, test bundle, etc.
• Source Files: Contains the source files that need to be compiled for the target. This includes Swift files, storyboards, resources (images, plist files), etc.
• Dependencies: Defines the dependencies of the target on other targets or libraries.
• Build Settings: Includes the settings that control the compilation process of the target. For example, architectures, code signing settings, compilation flags, etc.
• Build Phases: Determines which steps will be performed during the compilation process of the target. This includes compiling source files, linking libraries, copying resource files, etc.

Using Targets in Xcode

In Xcode projects, targets are managed in the “Targets” section located in the left panel of the project. From here, existing targets can be viewed and new targets can be added.

1. Creating a New Target

• Adding a Target: Right-click on the “Targets” section in the left panel of your Xcode project and select the “New Target” option.
• Selecting Product Type: Choose the type of the new target. For example, iOS Application, Framework, Test Target, etc.
• Target Configuration: Give a name to the new target and configure the necessary settings.

2. Editing an Existing Target

• Selecting the Target: Choose the target you want to edit from the “Targets” section in the left panel.
• Target Settings: Configure the build settings, dependencies, source files, and build phases for the selected target.

This comprehensive overview of the build process in Xcode covers the essential components such as targets, build phases, build rules, and schemes. Understanding and effectively utilizing these elements are crucial for successful software development in Xcode.