EVM vs. SVM: Smart Contracts

• Programs process instructions received from users or other programs.
• All programs do not maintain state. In other words, the data used by programs is sent to separate accounts through instructions.
• The program itself is stored in an executable checked account.
• All programs are owned by the BPF Loader and executed by the Solana Runtime.
• Developers typically write programs in Rust or C++. However, any language targeting LLVM and BPF backend can be chosen.
• All programs have a single entry point where instruction processing occurs (i.e., process_instruction). The following parameters are always included:
• program_id: pubkey,
• accounts: array,
• instruction_data: byte array

Unlike most other blockchains, Solana completely separates data and code. All data that programs interact with is stored in separate accounts and is called through instructions.

This model allows for comprehensive single programs to operate through various accounts without the need for additional deployments. A common example of this pattern can be seen between Native and SPL Programs.

Native Programs và Solana Program Library (SPL)

Solana có nhiều chương trình đóng vai trò là khối xây dựng cốt lõi cho các tương tác onchain.

Các chương trình này được chia thành Native Programs và Solana Program Library (SPL) Programs.

Native Programs cung cấp chức năng nền tảng cần thiết để vận hành các validator. Một trong những chương trình nổi tiếng nhất trong số này là System Program, chịu trách nhiệm quản lý các tài khoản mới và chuyển SOL giữa hai nhóm.

SPL Programs hỗ trợ nhiều hoạt động onchain khác nhau, bao gồm tạo token, trao đổi, cho vay, tạo stake pool và dịch vụ tên onchain. SPL Token Program có thể được gọi trực tiếp thông qua CLI. Các chương trình khác, như Associated Token Account Program, thường được cấu hình dưới dạng chương trình tùy chỉnh

Writing Programs

Programs are typically developed in Rust and C++. However, you can develop in any language targeting LLVM and BPF backend. Recent efforts by Neon Labs and Solang make EVM compatibility possible, allowing developers to write programs in Solidity.

Most Rust-based programs follow the architecture below:

Recently, Anchor has emerged as a framework for developing programs. Anchor reduces boilerplate and simplifies (de)serialization handling, similar to Ruby on Rails but for Rust-based programs. Programs are typically developed and tested in the Localhost and Devnet environments before being deployed to Testnet and Mainnet.

Solana supports the following environments:

Sau khi được triển khai vào một môi trường, các client có thể tương tác với các chương trình onchain thông qua kết nối RPC đến từng cluster.

Deploying Programs

Developers can deploy programs via the CLI as follows:

solana program deploy <PROGRAM_FILEPATH>

When a program is deployed, it is compiled into an ELF shared object (including BPF bytecode) and uploaded to the Solana cluster. Programs exist inside an account except when they are marked as executable and allocated to the BPF Loader. The account's address is used as the program_id to reference the program in all transactions.

Solana supports multiple BPF Loaders, including the recent Upgradable BPF Loader. BPF Loaders are responsible for managing program accounts and making this possible through the program_id for clients.

All programs have a single entry point where instruction processing occurs (i.e., process_instruction). The parameters always include:

• program_id: pubkey
• accounts: array
• instruction_data: byte array

Once called, programs are executed by the Solana Runtime.

Summary

• The Program in Solana corresponds to 'Executable account' on the Solana blockchain.
• The concept of smart contracts in Ethereum aligns with the concept of programs in Solana.
• Solana enables anyone to issue tokens without the need to deploy additional contracts.