Yul

These instructions do not have a direct representation in EVM or ZKsync VM. Instead, they perform auxiliary operations required for generating the target bytecode.

datasize

Original Yul auxiliary instruction.

Unlike on EVM, on ZKsync VM target this instruction returns the size of the header part of the calldata sent to the ContractDeployer. For more information, see CREATE.

LLVM IR codegen references:

1. zksolc compiler
2. Shared FE code

dataoffset

Original Yul auxiliary instruction.

Unlike on EVM, on ZKsync VM target this instruction has nothing to do with the offset. Instead, it returns the bytecode hash of the contract referenced by the Yul object identifier. Since our compiler translates instructions without analyzing the surrounding context, it is not possible to get the bytecode hash from anywhere else in datacopy. For more information, see CREATE.

LLVM IR codegen references:

1. zksolc compiler
2. Shared FE code

datacopy

Original Yul auxiliary instruction.

Unlike on EVM, on ZKsync VM target this instruction copies the bytecode hash passed as dataoffset to the destination. For more information, see CREATE.

The LLVM IR generator code.

setimmutable

Original Yul auxiliary instruction.

Writes immutables to the auxiliary heap.

For more information, see the Differences with Ethereum.

LLVM IR codegen references:

1. zksolc compiler
2. Shared FE code

loadimmutable

Original Yul auxiliary instruction.

Reads immutables from the ImmutableSimulator.

For more information, see the Differences with Ethereum.

LLVM IR codegen references:

1. zksolc compiler
2. Shared FE code

linkersymbol

Original Yul auxiliary instruction.

Returns the address of a deployable library. The address must be passed to zksolc with the --libraries option, otherwise a compile-time error will be produced.

There is a special zksolc execution mode that can be enabled with --missing-libraries flag. In this mode, the compiler will return the list of deployable libraries not provided with --libraries. This mode allows package managers like Hardhat to automatically deploy libraries.

For more information, see the Differences with Ethereum.

The LLVM IR generator code.

memoryguard

Original Yul auxiliary instruction.

Is a Yul optimizer hint which is not used by our compiler. Instead, its only argument is simply unwrapped and returned.

The LLVM IR generator code.

verbatim

Original Yul auxiliary instruction.

Unlike on EVM, on ZKsync VM target this instruction has nothing to do with inserting of EVM bytecode. Instead, it is used to implement ZKsync VM Yul Extensions available in the system mode. In order to compile a Yul contract with extensions, both Yul and system mode must be enabled (zksolc --yul --system-mode ...).

The LLVM IR generator code.