perf(evm): elide statically empty copy codegen

src/compiler/evm_frontend/evm_imported.cpp

@@ -216,6 +216,7 @@ const RuntimeFunctions &getRuntimeFunctionTable() {
       .GetTLoad = &evmGetTLoad,
       .SetTStore = &evmSetTStore,
       .SetCallDataCopy = &evmSetCallDataCopy,
+      .TouchExtCodeCopyAccount = &evmTouchExtCodeCopyAccount,
       .SetExtCodeCopy = &evmSetExtCodeCopy,
       .SetReturnDataCopy = &evmSetReturnDataCopy,
       .ExpandMemoryNoGas = &evmExpandMemoryNoGas,
@@ -674,6 +675,21 @@ void evmSetCallDataCopy(zen::runtime::EVMInstance *Instance,
   }
 }
 
+void evmTouchExtCodeCopyAccount(zen::runtime::EVMInstance *Instance,
+                                const uint8_t *Address) {
+  const zen::runtime::EVMModule *Module = Instance->getModule();
+  ZEN_ASSERT(Module && Module->Host);
+  evmc::address Addr = loadAddressFromLE(Address);
+
+  evmc_revision Rev = Instance->getRevision();
+  if (Rev >= EVMC_BERLIN &&
+      Module->Host->access_account(Addr) == EVMC_ACCESS_COLD) {
+    if (!Instance->chargeGas(zen::evm::ADDITIONAL_COLD_ACCOUNT_ACCESS_COST)) {
+      return;
+    }
+  }
+}
+
 void evmSetExtCodeCopy(zen::runtime::EVMInstance *Instance,
                        const uint8_t *Address, uint64_t DestOffset,
                        uint64_t Offset, uint64_t Size) {

src/compiler/evm_frontend/evm_imported.h

@@ -127,6 +127,7 @@ struct RuntimeFunctions {
   U256WithU256Fn GetTLoad;
   VoidWithU256U256Fn SetTStore;
   VoidWithUInt64UInt64UInt64Fn SetCallDataCopy;
+  VoidWithBytes32Fn TouchExtCodeCopyAccount;
   VoidWithBytes32UInt64UInt64UInt64Fn SetExtCodeCopy;
   UInt64WithUInt64UInt64UInt64Fn SetReturnDataCopy;
   VoidWithUInt64Fn ExpandMemoryNoGas;
@@ -218,6 +219,8 @@ const uint8_t *evmGetBlobHash(zen::runtime::EVMInstance *Instance,
 const intx::uint256 *evmGetBlobBaseFee(zen::runtime::EVMInstance *Instance);
 void evmSetCallDataCopy(zen::runtime::EVMInstance *Instance,
                         uint64_t DestOffset, uint64_t Offset, uint64_t Size);
+void evmTouchExtCodeCopyAccount(zen::runtime::EVMInstance *Instance,
+                                const uint8_t *Address);
 void evmSetExtCodeCopy(zen::runtime::EVMInstance *Instance,
                        const uint8_t *Address, uint64_t DestOffset,
                        uint64_t Offset, uint64_t Size);

src/compiler/evm_frontend/evm_mir_compiler.cpp

@@ -5035,6 +5035,11 @@ void EVMMirBuilder::handleMStore8(Operand AddrComponents,
 void EVMMirBuilder::handleMCopy(Operand DestAddrComponents,
                                 Operand SrcAddrComponents,
                                 Operand LengthComponents) {
+  if (LengthComponents.isConstU64() &&
+      LengthComponents.getConstValue()[0] == 0) {
+    return;
+  }
+
   MType *I64Type = &Ctx.I64Type;
   MInstruction *Zero = createIntConstInstruction(I64Type, 0);
 
@@ -6737,6 +6742,18 @@ void EVMMirBuilder::handleExtCodeCopy(Operand AddressComponents,
                                       Operand OffsetComponents,
                                       Operand SizeComponents) {
   const auto &RuntimeFunctions = getRuntimeFunctionTable();
+  if (SizeComponents.isConstU64() && SizeComponents.getConstValue()[0] == 0) {
+#ifdef ZEN_ENABLE_EVM_GAS_REGISTER
+    syncGasToMemory();
+#endif
+    callRuntimeForWithErrorCheck<void, const uint8_t *>(
+        RuntimeFunctions.TouchExtCodeCopyAccount, AddressComponents);
+#ifdef ZEN_ENABLE_EVM_GAS_REGISTER
+    reloadGasFromMemory();
+#endif
+    return;
+  }
+
   // Use max uint64_t value if the offset/size is not 64-bit, because the
   // extcodecopy will fill zeros when offset is beyond code size or handle large
   // size properly.

tests/evm_asm/extcodecopy_zero_size.easm

@@ -0,0 +1,12 @@
+// EXTCODECOPY with zero size keeps existing memory and skips code copy work
+PUSH1 0x2C
+PUSH1 0x00
+MSTORE
+PUSH1 0x00
+PUSH32 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
+PUSH32 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
+PUSH1 0x00
+EXTCODECOPY
+PUSH1 0x20
+PUSH1 0x00
+RETURN

tests/evm_asm/extcodecopy_zero_size.evm.hex

@@ -0,0 +1 @@
+602C60005260007FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF60003C60206000F3

tests/evm_asm/extcodecopy_zero_size.expected

@@ -0,0 +1,8 @@
+status: success
+error_code: 0
+stack: []
+memory: '000000000000000000000000000000000000000000000000000000000000002C'
+storage: {}
+transient_storage: {}
+return: '000000000000000000000000000000000000000000000000000000000000002C'
+events: []

tests/evm_asm/mcopy_zero_size.easm

@@ -0,0 +1,11 @@
+// MCOPY with zero size keeps existing memory and skips source/destination access
+PUSH1 0x2D
+PUSH1 0x00
+MSTORE
+PUSH1 0x00
+PUSH32 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
+PUSH32 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
+MCOPY
+PUSH1 0x20
+PUSH1 0x00
+RETURN

tests/evm_asm/mcopy_zero_size.evm.hex

@@ -0,0 +1 @@
+602D60005260007FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5E60206000F3

tests/evm_asm/mcopy_zero_size.expected

@@ -0,0 +1,8 @@
+status: success
+error_code: 0
+stack: []
+memory: '000000000000000000000000000000000000000000000000000000000000002D'
+storage: {}
+transient_storage: {}
+return: '000000000000000000000000000000000000000000000000000000000000002D'
+events: []