[ETCM-912] Implement EXTCODESIZE changes

Author: lukasz-golebiewski

src/main/scala/io/iohk/ethereum/vm/OpCode.scala

@@ -452,13 +452,34 @@ case object CODECOPY extends OpCode(0x39, 3, 0, _.G_verylow) {
 
 case object GASPRICE extends ConstOp(0x3a)(_.env.gasPrice)
 
-case object EXTCODESIZE extends OpCode(0x3b, 1, 1, _.G_extcode) with ConstGas {
+case object EXTCODESIZE extends OpCode(0x3b, 1, 1, _.G_zero) {
   protected def exec[W <: WorldStateProxy[W, S], S <: Storage[S]](state: ProgramState[W, S]): ProgramState[W, S] = {
-    val (addr, stack1) = state.stack.pop
-    val codeSize = state.world.getCode(Address(addr)).size
+    val (addrUint, stack1) = state.stack.pop
+    val addr = Address(addrUint)
+    val codeSize = state.world.getCode(addr).size
     val stack2 = stack1.push(UInt256(codeSize))
-    state.withStack(stack2).step()
+    state.withStack(stack2).addAccessedAddress(addr).step()
+  }
+
+  protected def varGas[W <: WorldStateProxy[W, S], S <: Storage[S]](state: ProgramState[W, S]): BigInt = {
+
+    val currentBlockNumber = state.env.blockHeader.number
+    val etcFork = state.config.blockchainConfig.etcForkForBlockNumber(currentBlockNumber)
+
+    val eip2929Enabled = isEip2929Enabled(etcFork)
+
+    if (eip2929Enabled) {
+      val (addr, _) = state.stack.pop
+      if (state.accessedAddresses.contains(Address(addr)))
+        state.config.feeSchedule.G_warm_storage_read
+      else
+        state.config.feeSchedule.G_cold_account_access
+    } else
+      state.config.feeSchedule.G_extcode
   }
+
+  private def isEip2929Enabled(etcFork: EtcFork): Boolean = etcFork >= EtcForks.Magneto
+
 }
 
 case object EXTCODECOPY extends OpCode(0x3c, 4, 0, _.G_extcode) {

src/test/scala/io/iohk/ethereum/vm/CreateOpcodeSpec.scala

@@ -253,7 +253,7 @@ class CreateOpcodeSpec extends AnyWordSpec with Matchers with ScalaCheckProperty
         result.world.getGuaranteedAccount(newAccountAddress())
         val addr = newAccountAddress()
 
-        result.stateOut.accessedAddresses should contain (addr)
+        result.stateOut.accessedAddresses should contain(addr)
       }
     }
 

src/test/scala/io/iohk/ethereum/vm/OpCodeGasSpec.scala

@@ -51,7 +51,6 @@ class OpCodeGasSpec extends AnyFunSuite with OpCodeTesting with Matchers with Sc
     CALLVALUE -> G_base,
     CALLDATALOAD -> G_verylow,
     CALLDATASIZE -> G_base,
-    EXTCODESIZE -> G_extcode,
     BLOCKHASH -> G_blockhash,
     COINBASE -> G_base,
     TIMESTAMP -> G_base,
@@ -582,5 +581,15 @@ class OpCodeGasSpec extends AnyFunSuite with OpCodeTesting with Matchers with Sc
 
   }
 
+  test(EXTCODESIZE) { op =>
+    val stateGen = getProgramStateGen(
+      stackGen = getStackGen(elems = 1)
+    )
+    forAll(stateGen) { stateIn =>
+      val stateOut = op.execute(stateIn)
+      verifyGas(G_extcode, stateIn, stateOut)
+    }
+  }
+
   verifyAllOpCodesRegistered(except = CREATE, CREATE2, CALL, CALLCODE, DELEGATECALL, STATICCALL, INVALID)
 }

src/test/scala/io/iohk/ethereum/vm/OpCodeGasSpecPostEip2929.scala

@@ -0,0 +1,50 @@
+package io.iohk.ethereum.vm
+
+import org.scalatest.funsuite.AnyFunSuite
+import org.scalatest.matchers.should.Matchers
+import org.scalatestplus.scalacheck.ScalaCheckPropertyChecks
+
+import io.iohk.ethereum.domain.Address
+import io.iohk.ethereum.vm.Generators._
+
+import Fixtures.blockchainConfig
+
+class OpCodeGasSpecPostEip2929 extends AnyFunSuite with OpCodeTesting with Matchers with ScalaCheckPropertyChecks {
+
+  override val config: EvmConfig = EvmConfig.MagnetoConfigBuilder(blockchainConfig)
+
+  import config.feeSchedule._
+
+  test(EXTCODESIZE) { op =>
+    val stateGen = getProgramStateGen(
+      evmConfig = config,
+      stackGen = getStackGen(elems = 1),
+      blockNumberGen = getUInt256Gen(Fixtures.MagnetoBlockNumber)
+    )
+    val codeGen = getByteStringGen(0, 512)
+
+    forAll(stateGen) { stateIn =>
+      val (addrUint, _) = stateIn.stack.pop
+      val addr = Address(addrUint)
+      stateIn.accessedAddresses shouldNot contain(addr)
+
+      val stateOut = op.execute(stateIn)
+
+      verifyGas(G_cold_account_access, stateIn, stateOut)
+      stateOut.accessedAddresses should contain(addr)
+    }
+
+    forAll(stateGen, codeGen) { (stateIn, extCode) =>
+      val (addrUint, _) = stateIn.stack.pop
+      val addr = Address(addrUint)
+      val program = Program(extCode)
+      val world1 = stateIn.world.saveCode(addr, program.code)
+      val stateInWithExtCode = stateIn.withWorld(world1).addAccessedAddress(addr)
+
+      val stateOut = op.execute(stateInWithExtCode)
+
+      verifyGas(G_warm_storage_read, stateIn, stateOut)
+      stateOut.accessedAddresses should contain(addr)
+    }
+  }
+}