From dd7a89914ae4744202f67a845df5193315320129 Mon Sep 17 00:00:00 2001
From: dyedm1 <henry@hyf.one>
Date: Sat, 7 Oct 2023 14:45:52 -0400
Subject: [PATCH] feat: simplify bootstrap code and remove PUSH0 usage

---
 README.md                 | 10 ++++-----
 src/Create4Factory.sol    | 47 +++++++++++++++------------------------
 test/Create4Factory.t.sol |  5 ++---
 3 files changed, 24 insertions(+), 38 deletions(-)

diff --git a/README.md b/README.md
index fe7df04..80353da 100644
--- a/README.md
+++ b/README.md
@@ -23,19 +23,17 @@
 ### Initcode for address derivation
 
 For `Create4Factory`, the `initCode` is constructed as follows:
-- Code segment 1: `5f5f5f5f5f73` 
-- `Create4Factory` address: `ffffffffffffffffffffffffffffffffffffffff`
-- Code segment 2: `5af13d5f5f3e3d5ff3`
-- Deployer address (user calling `create4`): `ffffffffffffffffffffffffffffffffffffffff`
+- Executable constructor: `3636363636335af13d36363e3d36f3` 
+- Deployer address (user calling `create4`): `ffffffffffffffffffffffffffffffffffffffff` (20-byte salt)
 
-Result: `0x5f5f5f5f5f73<Create4Factory address>5af13d5f5f3e3d5ff3<deployer address>`
+Result: `0x3636363636335af13d36363e3d36f3<deployer address>`
 #### Example
 If we have
 - `Create4Factory` address: `0xe358511cd9bf45c8a4d4aaf96ad5f6234ad20282` (note: not the real-world address!)
 - Deployer address: `0xab5801a7d398351b8be11c439e05c5b3259aec9b` (Vb)
 
 Our `initCode` would be:
-`0x5f5f5f5f5f73e358511cd9bf45c8a4d4aaf96ad5f6234ad202825af13d5f5f3e3d5ff3ab5801a7d398351b8be11c439e05c5b3259aec9b`
+`0x3636363636335af13d36363e3d36f3ab5801a7d398351b8be11c439e05c5b3259aec9b`
 
 ### Features
 
diff --git a/src/Create4Factory.sol b/src/Create4Factory.sol
index 7639a23..b059438 100644
--- a/src/Create4Factory.sol
+++ b/src/Create4Factory.sol
@@ -10,34 +10,27 @@ pragma solidity ^0.8.20;
  */
 contract Create4Factory {
     /*
-        [26 BYTES]
-        PUSH0 // retSize: 0
-        PUSH0 // retOffset: 0
-        PUSH0 // argsSize: 0
-        PUSH0 // argsOffset: 0
-        PUSH0 // value: 0
-        PUSH20 (0x0000000000000000000000000000000000000000) // FACTORY ADDRESS(THIS), FILLED DYNAMICALLY 
-        Right-padded with 0s to 32 bytes
-    */
-    bytes32 internal constant BOOTSTRAP_CODE_SECTION_1 =
-        hex"5f5f5f5f5f73000000000000000000000000000000000000000000000000";
-
-    /*
-        [29 BYTES]
+        [35 BYTES]
+        CALLDATASIZE // retSize: 0
+        CALLDATASIZE // retOffset: 0
+        CALLDATASIZE // argsSize: 0
+        CALLDATASIZE // argsOffset: 0
+        CALLDATASIZE // value: 0
+        CALLER // Create4Factory 
         GAS // gas (gas remaining in frame)
         CALL
         RETURNDATASIZE // size (of returned code to copy)
-        PUSH0 // offset: 0
-        PUSH0 // destOffset: 0
+        CALLDATASIZE // offset: 0
+        CALLDATASIZE // destOffset: 0
         RETURNDATACOPY
         RETURNDATASIZE // size (of code to return/deploy)
-        PUSH0 // offset: 0
+        CALLDATASIZE // offset: 0
         RETURN
         (0x0000000000000000000000000000000000000000) // MSG.SENDER, FILLED DYNAMICALLY (appended for frontrunning protection)
         Right-padded with 0s to 32 bytes
     */
-    bytes32 internal constant BOOTSTRAP_CODE_SECTION_2 =
-        hex"5af13d5f5f3e3d5ff30000000000000000000000000000000000000000000000";
+    bytes32 internal constant BOOTSTRAP_CODE = hex"3636363636335af13d36363e3d36f30000000000000000000000000000000000"; 
+
 
     uint256 internal constant UINT256_MAX = 2 ** 256 - 1;
 
@@ -66,12 +59,10 @@ contract Create4Factory {
         currentDeployment = deployedCode;
 
         assembly {
-            mstore(0, BOOTSTRAP_CODE_SECTION_1)
-            mstore(6, shl(96, address()))
-            mstore(26, BOOTSTRAP_CODE_SECTION_2)
-            mstore(35, shl(96, caller()))
+            mstore(0, BOOTSTRAP_CODE)
+            mstore(15, shl(96, caller()))
 
-            newContract := create2(0, 0, 55, salt)
+            newContract := create2(0, 0, 35, salt)
         }
     }
 
@@ -101,12 +92,10 @@ contract Create4Factory {
                 tstore(i, mload(add(deployedCode, add(32, mul(i, 32)))))
             }
 
-            mstore(0, BOOTSTRAP_CODE_SECTION_1)
-            mstore(6, shl(96, address()))
-            mstore(26, BOOTSTRAP_CODE_SECTION_2)
-            mstore(35, shl(96, caller()))
+            mstore(0, BOOTSTRAP_CODE)
+            mstore(15, shl(96, caller()))
 
-            newContract := create2(0, 0, 55, salt)
+            newContract := create2(0, 0, 35, salt)
         }
     }
 
diff --git a/test/Create4Factory.t.sol b/test/Create4Factory.t.sol
index d5d0143..f556ce8 100644
--- a/test/Create4Factory.t.sol
+++ b/test/Create4Factory.t.sol
@@ -6,8 +6,7 @@ import {Test, console2} from "forge-std/Test.sol";
 import {Create4Factory} from "src/Create4Factory.sol";
 
 contract TestCreate4Factory is Test {
-    bytes6 internal constant BOOTSTRAP_CODE_SECTION_1 = hex"5f5f5f5f5f73";
-    bytes9 internal constant BOOTSTRAP_CODE_SECTION_2 = hex"5af13d5f5f3e3d5ff3";
+    bytes15 internal constant BOOTSTRAP_CODE = hex"3636363636335af13d36363e3d36f3"; 
     address internal constant EIP_1153_MAGIC = address(0x4549502d31313533);
 
     Create4Factory internal C4F;
@@ -15,7 +14,7 @@ contract TestCreate4Factory is Test {
     function expectedAddress(address deployer, bytes32 salt) internal view returns (address) {
         bytes32 bootstrapCodeHash = keccak256(
             abi.encodePacked(
-                BOOTSTRAP_CODE_SECTION_1, bytes20(address(C4F)), BOOTSTRAP_CODE_SECTION_2, bytes20(address(deployer))
+                BOOTSTRAP_CODE, bytes20(address(deployer))
             )
         );