Slow forge build compilation times

[alex-roytikh-pop]

Component

Forge

Have you ensured that all of these are up to date?

• Foundry
• Foundryup

What version of Foundry are you on?

forge 0.2.0 (f8aa4af 2024-08-17T00:18:27.502409000Z)

What command(s) is the bug in?

forge build --force

Operating System

macOS (Apple Silicon)

Describe the bug

My team is experiencing very long forge build times, hurting Dev UX. I have spent a good amount of time reading through previous issues related to slow compilation times, but cannot find anything that would be relevant today. Currently running Apple Silicon with Sonoma 14.5.

Project Bytesize

du -sh out
936M    out

I am unable to reproduce the issue with https://github.com/Vectorized/solady. It takes only 15.47s to compile 152 files. https://github.com/latticexyz/mud takes only 1.46s to compile 91 files.

Previous issues I am referencing:
foundry-rs/forge-std#217
foundry-rs/forge-std#225
ethereum/solidity#15141

Things I have tried

1. forge clean & forge build --force
2. Enabling and disabling via_ir.
3. Solc versions
4. increasing threads to numbers greater than 0. Only 1 thread appears to be used by solc process in htop regardless of setting.

Foundry Configuration

[profile.default]
src = "contracts"
out = "out"
allow_paths = ["../../node_modules"]
libs = ["node_modules","lib"]
test = "test/foundry"
cache_path = "forge-cache"
solc_version = "0.8.26"
evm_version = "cancun"

Build Times

Solc 0.8.13

time forge build --force

[⠒] Compiling...
[⠰] Compiling 556 files with Solc 0.8.13
[⠑] Solc 0.8.13 finished in 262.17s
Compiler run successful

forge build --force  255.94s user 6.55s system 99% cpu 4:23.92 total

Solc 0.8.26
30s quicker than solc 0.8.13

time forge build --force
[⠒] Compiling...
[⠘] Compiling 556 files with Solc 0.8.26
[⠢] Solc 0.8.26 finished in 230.09s
Compiler run successful

forge build --force  225.24s user 5.83s system 99% cpu 3:52.93 total

Solc 0.8.26 via_ir enabled
This runs into the stack too deep issue.

time forge build --force
[⠒] Compiling...
[⠢] Compiling 556 files with Solc 0.8.26
[⠰] Solc 0.8.26 finished in 185.66s
Error: 
Compiler run failed:
Error: Yul exception:Variable value4 is 1 too deep in the stack [ JUNK value4 var_lootSet_mpos _60 _62 var_idx_5 value3 var_total value5 _70 dataSlot_5 value6 value1_3 value2_2 _59 _71 var_setIdx_1 slot_2 ]
memoryguard was present.
YulException: Variable value4 is 1 too deep in the stack [ JUNK value4 var_lootSet_mpos _60 _62 var_idx_5 value3 var_total value5 _70 dataSlot_5 value6 value1_3 value2_2 _59 _71 var_setIdx_1 slot_2 ]
memoryguard was present.

forge build --force  184.66s user 1.06s system 99% cpu 3:06.10 total

Help here would be appreciated! People that have experienced, or investigated the issue previously:

@zerosnacks @mattsse @ZeroEkkusu @marktoda @mds1

[alex-roytikh-pop]

We have a lot of inline assembly in our contracts, is it possible that there is non-memory-safe assembly causing some sort of compiler issue?

Is there a good way to analyze this?

[aodhgan]

increasing threads to numbers greater than 0. Only 1 thread appears to be used by solc process in htop regardless of setting.

i believe this config var is only relevant for fuzzing, (unfortunately) not compiling

[zerosnacks]

Unrelated to Foundry, forge build simply wraps the solc compiler. Slow compilation times are almost entirely due to solc. To speed up compilation time try to reduce the amount of dependencies you are pulling in and make sure you enable caching to speed up incremental builds.

[vseae]

My computer is m3 24gb system version Sonoma 14.6.1

The test script tests a token, inherits the Test contract of forge, and the configuration is enabled via_ir = true, compiler version 0.8.26

When I enable via_ir, it takes me at least a minute to compile a file.

This problem seems to only occur in the inheritance of the forge test contract and the latest macos system.

[ZeroEkkusu]

@vseae Do you mean that a some change in Forge Std has impacted the compilation time via-ir - what happens if you downgrade forge-std with forge install foundry-rs/forge-std@ and then an old version tag from here?

@alex-roytikh-pop

I am unable to reproduce the issue with https://github.com/Vectorized/solady.

Solady uses custom files for Forge Std, can you try using them to see if there's difference?