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Optimizer dilemma: Unpacking the Ethereum optimization mechanisms
In this article, we delve into the world of the Ethereum optimizer and examine why « address (this). Balance « is not always optimized as » self.balance () « .
Background about solidity compilers
The Ethereum solidity compiler is a key element that translates a high -level code written in solidity (programming language used to build decentralized applications) to a low level byte. This process includes a number of optimization stages aimed at improving performance, readability and code maintenance.
Optimizer: Key element
The Ethereum virtual machine (EVM) has an optimizer that works on a solidity compiler. Its basic function is to reduce the size and complexity of the bay code produced by the compiler while maintaining or increasing the accuracy of the optimized code. The optimizer considers various factors, including:
- Gas cost : Higher gas costs can lead to optimization decision.
- Code length : longer code databases will be optimized more often for performance.
- Setting the instructions
: Frequent use of complex instructions may require optimization.
Why Ten). Balance is not always optimized
Let’s consider the example:
`Solidity
Pragma solidity ^0.8.0;
Mycontract contract {
Balance function () Public View Returns (Uint256) {
Return address (this). balance;
}
// We introduce a simple optimization: when it is called self.balance (),
// We update the balance without the use of the address (this). Balance.
Update function Balalance () public {
uint256 newbalance = self.balance ();
address (this). Balance = 0; // This line can be optimized
}
}
In this case, the optimizer will probably decide to optimize the address » This is due to the fact that the update of the local variable without the use of its original value may reduce gas consumption.
« self.balance ()vs. address (this). Balance ()difference
Although this may seem that `self.balance () 'and' address (this). Balance () is equivalent, there is a significant distinction:
- Self.balance ()
Returns the balance of the current instance of the contract.
address (this). Balance ()reimburse the balance of the current address of the contract.
This means that when calling "Bolance () `'we want to update the local variable in the current contract (' self '), instead of modifying the global condition. Using the "address (this). Balance (), we make sure that the optimization is used correctly because it refers to local value instead of global.
Application
To sum up, while the solidity compiler and its optimizer strive to optimize the code in terms of performance, there are scenarios in which optimizations can not always be used or even intentionally missed. The key result of this example is that the difference between « self.balance ()and "address (this). Balance ()` lies in their reference semantics, which can affect optimization decisions.
As programmers working with EVM Ethereum, understanding these subtleties will help you write a more efficient, legible and maintained code while minimizing gas consumption.