EIP-2315: Simple Subroutines for the EVM (#11629)

ethcore/evm/src/instructions.rs

@@ -321,6 +321,13 @@ enum_with_from_u8! {
         #[doc = "Makes a log entry, 4 topics."]
         LOG4 = 0xa4,
 
+        #[doc = "Marks the entry point to a subroutine."]
+        BEGINSUB = 0x5c,
+        #[doc = "Returns from a subroutine."]
+        RETURNSUB = 0x5d,
+        #[doc = "Jumps to a defined BEGINSUB subroutine."]
+        JUMPSUB = 0x5e,
+
         #[doc = "create a new account with associated code"]
         CREATE = 0xf0,
         #[doc = "message-call into an account"]
@@ -591,6 +598,9 @@ lazy_static! {
         arr[LOG2 as usize] = Some(InstructionInfo::new("LOG2", 4, 0, GasPriceTier::Special));
         arr[LOG3 as usize] = Some(InstructionInfo::new("LOG3", 5, 0, GasPriceTier::Special));
         arr[LOG4 as usize] = Some(InstructionInfo::new("LOG4", 6, 0, GasPriceTier::Special));
+        arr[BEGINSUB as usize] = Some(InstructionInfo::new("BEGINSUB", 0, 0, GasPriceTier::Base));
+        arr[JUMPSUB as usize] = Some(InstructionInfo::new("JUMPSUB", 1, 0, GasPriceTier::High));
+        arr[RETURNSUB as usize] = Some(InstructionInfo::new("RETURNSUB", 0, 0, GasPriceTier::Low));
         arr[CREATE as usize] = Some(InstructionInfo::new("CREATE", 3, 1, GasPriceTier::Special));
         arr[CALL as usize] = Some(InstructionInfo::new("CALL", 7, 1, GasPriceTier::Special));
         arr[CALLCODE as usize] = Some(InstructionInfo::new("CALLCODE", 7, 1, GasPriceTier::Special));

ethcore/evm/src/interpreter/mod.rs

@@ -61,6 +61,10 @@ const TWO_POW_96: U256 = U256([0, 0x100000000, 0, 0]); //0x1 00000000 00000000 0
 const TWO_POW_224: U256 = U256([0, 0, 0, 0x100000000]); //0x1 00000000 00000000 00000000 00000000 00000000 00000000 00000000
 const TWO_POW_248: U256 = U256([0, 0, 0, 0x100000000000000]); //0x1 00000000 00000000 00000000 00000000 00000000 00000000 00000000 000000
 
+/// Maximum subroutine stack size as specified in
+/// https://eips.ethereum.org/EIPS/eip-2315.
+pub const MAX_SUB_STACK_SIZE: usize = 1023;
+
 fn to_biguint(x: U256) -> BigUint {
     let mut bytes = [0u8; 32];
     x.to_little_endian(&mut bytes);
@@ -101,6 +105,8 @@ enum InstructionResult<Gas> {
     Ok,
     UnusedGas(Gas),
     JumpToPosition(U256),
+    JumpToSubroutine(U256),
+    ReturnFromSubroutine(usize),
     StopExecutionNeedsReturn {
         /// Gas left.
         gas: Gas,
@@ -183,8 +189,10 @@ pub struct Interpreter<Cost: CostType> {
     do_trace: bool,
     done: bool,
     valid_jump_destinations: Option<Arc<BitSet>>,
+    valid_subroutine_destinations: Option<Arc<BitSet>>,
     gasometer: Option<Gasometer<Cost>>,
     stack: VecStack<U256>,
+    return_stack: Vec<usize>,
     resume_output_range: Option<(U256, U256)>,
     resume_result: Option<InstructionResult<Cost>>,
     last_stack_ret_len: usize,
@@ -290,10 +298,12 @@ impl<Cost: CostType> Interpreter<Cost> {
         let params = InterpreterParams::from(params);
         let informant = informant::EvmInformant::new(depth);
         let valid_jump_destinations = None;
+        let valid_subroutine_destinations = None;
         let gasometer = Cost::from_u256(params.gas)
             .ok()
             .map(|gas| Gasometer::<Cost>::new(gas));
         let stack = VecStack::with_capacity(schedule.stack_limit, U256::zero());
+        let return_stack = Vec::with_capacity(MAX_SUB_STACK_SIZE);
 
         Interpreter {
             cache,
@@ -301,8 +311,10 @@ impl<Cost: CostType> Interpreter<Cost> {
             reader,
             informant,
             valid_jump_destinations,
+            valid_subroutine_destinations,
             gasometer,
             stack,
+            return_stack,
             done: false,
             // Overridden in `step_inner` based on
             // the result of `ext.trace_next_instruction`.
@@ -478,7 +490,8 @@ impl<Cost: CostType> Interpreter<Cost> {
                 if self.valid_jump_destinations.is_none() {
                     self.valid_jump_destinations = Some(
                         self.cache
-                            .jump_destinations(&self.params.code_hash, &self.reader.code),
+                            .jump_and_sub_destinations(&self.params.code_hash, &self.reader.code)
+                            .0,
                     );
                 }
                 let jump_destinations = self
@@ -491,6 +504,28 @@ impl<Cost: CostType> Interpreter<Cost> {
                 };
                 self.reader.position = pos;
             }
+            InstructionResult::JumpToSubroutine(position) => {
+                if self.valid_subroutine_destinations.is_none() {
+                    self.valid_subroutine_destinations = Some(
+                        self.cache
+                            .jump_and_sub_destinations(&self.params.code_hash, &self.reader.code)
+                            .1,
+                    );
+                }
+                let subroutine_destinations = self
+                    .valid_subroutine_destinations
+                    .as_ref()
+                    .expect("subroutine_destinations are initialized on first jump; qed");
+                let pos = match self.verify_jump(position, subroutine_destinations) {
+                    Ok(x) => x,
+                    Err(e) => return InterpreterResult::Done(Err(e)),
+                };
+                self.return_stack.push(self.reader.position);
+                self.reader.position = pos + 1;
+            }
+            InstructionResult::ReturnFromSubroutine(pos) => {
+                self.reader.position = pos;
+            }
             InstructionResult::StopExecutionNeedsReturn {
                 gas,
                 init_off,
@@ -537,20 +572,20 @@ impl<Cost: CostType> Interpreter<Cost> {
     ) -> vm::Result<()> {
         let schedule = ext.schedule();
 
-        if (instruction == instructions::DELEGATECALL && !schedule.have_delegate_call)
+        use instructions::*;
-            || (instruction == instructions::CREATE2 && !schedule.have_create2)
+        if (instruction == DELEGATECALL && !schedule.have_delegate_call)
-            || (instruction == instructions::STATICCALL && !schedule.have_static_call)
+            || (instruction == CREATE2 && !schedule.have_create2)
-            || ((instruction == instructions::RETURNDATACOPY
+            || (instruction == STATICCALL && !schedule.have_static_call)
-                || instruction == instructions::RETURNDATASIZE)
+            || ((instruction == RETURNDATACOPY || instruction == RETURNDATASIZE)
                 && !schedule.have_return_data)
-            || (instruction == instructions::REVERT && !schedule.have_revert)
+            || (instruction == REVERT && !schedule.have_revert)
-            || ((instruction == instructions::SHL
+            || ((instruction == SHL || instruction == SHR || instruction == SAR)
-                || instruction == instructions::SHR
-                || instruction == instructions::SAR)
                 && !schedule.have_bitwise_shifting)
-            || (instruction == instructions::EXTCODEHASH && !schedule.have_extcodehash)
+            || (instruction == EXTCODEHASH && !schedule.have_extcodehash)
-            || (instruction == instructions::CHAINID && !schedule.have_chain_id)
+            || (instruction == CHAINID && !schedule.have_chain_id)
-            || (instruction == instructions::SELFBALANCE && !schedule.have_selfbalance)
+            || (instruction == SELFBALANCE && !schedule.have_selfbalance)
+            || ((instruction == BEGINSUB || instruction == JUMPSUB || instruction == RETURNSUB)
+                && !schedule.have_subs)
         {
             return Err(vm::Error::BadInstruction {
                 instruction: instruction as u8,
@@ -623,6 +658,29 @@ impl<Cost: CostType> Interpreter<Cost> {
             instructions::JUMPDEST => {
                 // ignore
             }
+            instructions::BEGINSUB => {
+                return Err(vm::Error::InvalidSubEntry);
+            }
+            instructions::JUMPSUB => {
+                if self.return_stack.len() >= MAX_SUB_STACK_SIZE {
+                    return Err(vm::Error::OutOfSubStack {
+                        wanted: 1,
+                        limit: MAX_SUB_STACK_SIZE,
+                    });
+                }
+                let sub_destination = self.stack.pop_back();
+                return Ok(InstructionResult::JumpToSubroutine(sub_destination));
+            }
+            instructions::RETURNSUB => {
+                if let Some(pos) = self.return_stack.pop() {
+                    return Ok(InstructionResult::ReturnFromSubroutine(pos));
+                } else {
+                    return Err(vm::Error::SubStackUnderflow {
+                        wanted: 1,
+                        on_stack: 0,
+                    });
+                }
+            }
             instructions::CREATE | instructions::CREATE2 => {
                 let endowment = self.stack.pop_back();
                 let init_off = self.stack.pop_back();
@@ -1413,6 +1471,7 @@ impl<Cost: CostType> Interpreter<Cost> {
         if valid_jump_destinations.contains(jump) && U256::from(jump) == jump_u {
             Ok(jump)
         } else {
+            // Note: if jump > usize, BadJumpDestination value is trimmed
             Err(vm::Error::BadJumpDestination { destination: jump })
         }
     }

ethcore/evm/src/interpreter/shared_cache.rs

@@ -26,6 +26,7 @@ use std::sync::Arc;
 const DEFAULT_CACHE_SIZE: usize = 4 * 1024 * 1024;
 
 // stub for a HeapSizeOf implementation.
+#[derive(Clone)]
 struct Bits(Arc<BitSet>);
 
 impl HeapSizeOf for Bits {
@@ -35,9 +36,21 @@ impl HeapSizeOf for Bits {
     }
 }
 
+#[derive(Clone)]
+struct CacheItem {
+    jump_destination: Bits,
+    sub_entrypoint: Bits,
+}
+
+impl HeapSizeOf for CacheItem {
+    fn heap_size_of_children(&self) -> usize {
+        self.jump_destination.heap_size_of_children() + self.sub_entrypoint.heap_size_of_children()
+    }
+}
+
 /// Global cache for EVM interpreter
 pub struct SharedCache {
-    jump_destinations: Mutex<MemoryLruCache<H256, Bits>>,
+    jump_destinations: Mutex<MemoryLruCache<H256, CacheItem>>,
 }
 
 impl SharedCache {
@@ -50,47 +63,62 @@ impl SharedCache {
     }
 
     /// Get jump destinations bitmap for a contract.
-    pub fn jump_destinations(&self, code_hash: &Option<H256>, code: &[u8]) -> Arc<BitSet> {
+    pub fn jump_and_sub_destinations(
+        &self,
+        code_hash: &Option<H256>,
+        code: &[u8],
+    ) -> (Arc<BitSet>, Arc<BitSet>) {
         if let Some(ref code_hash) = code_hash {
             if code_hash == &KECCAK_EMPTY {
-                return Self::find_jump_destinations(code);
+                let cache_item = Self::find_jump_and_sub_destinations(code);
+                return (cache_item.jump_destination.0, cache_item.sub_entrypoint.0);
             }
 
             if let Some(d) = self.jump_destinations.lock().get_mut(code_hash) {
-                return d.0.clone();
+                return (d.jump_destination.0.clone(), d.sub_entrypoint.0.clone());
             }
         }
 
-        let d = Self::find_jump_destinations(code);
+        let d = Self::find_jump_and_sub_destinations(code);
 
         if let Some(ref code_hash) = code_hash {
-            self.jump_destinations
+            self.jump_destinations.lock().insert(*code_hash, d.clone());
-                .lock()
-                .insert(*code_hash, Bits(d.clone()));
         }
 
-        d
+        (d.jump_destination.0, d.sub_entrypoint.0)
     }
 
-    fn find_jump_destinations(code: &[u8]) -> Arc<BitSet> {
+    fn find_jump_and_sub_destinations(code: &[u8]) -> CacheItem {
         let mut jump_dests = BitSet::with_capacity(code.len());
+        let mut sub_entrypoints = BitSet::with_capacity(code.len());
         let mut position = 0;
 
         while position < code.len() {
             let instruction = Instruction::from_u8(code[position]);
 
             if let Some(instruction) = instruction {
-                if instruction == instructions::JUMPDEST {
+                match instruction {
+                    instructions::JUMPDEST => {
                         jump_dests.insert(position);
-                } else if let Some(push_bytes) = instruction.push_bytes() {
+                    }
+                    instructions::BEGINSUB => {
+                        sub_entrypoints.insert(position);
+                    }
+                    _ => {
+                        if let Some(push_bytes) = instruction.push_bytes() {
                             position += push_bytes;
                         }
                     }
+                }
+            }
             position += 1;
         }
 
         jump_dests.shrink_to_fit();
-        Arc::new(jump_dests)
+        CacheItem {
+            jump_destination: Bits(Arc::new(jump_dests)),
+            sub_entrypoint: Bits(Arc::new(sub_entrypoints)),
+        }
     }
 }
 
@@ -100,15 +128,92 @@ impl Default for SharedCache {
     }
 }
 
-#[test]
+#[cfg(test)]
-fn test_find_jump_destinations() {
+mod test {
-    use rustc_hex::FromHex;
+    use super::*;
+    use hex_literal::hex;
+
+    #[test]
+    fn test_find_jump_destinations() {
         // given
-    let code = "7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff5b01600055".from_hex().unwrap();
+
+        // 0000 7F   PUSH32 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
+        // 0021 7F   PUSH32 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff
+        // 0042 5B   JUMPDEST
+        // 0043 01   ADD
+        // 0044 60   PUSH1 0x00
+        // 0046 55   SSTORE
+        let code = hex!("7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff5b01600055");
 
         // when
-    let valid_jump_destinations = SharedCache::find_jump_destinations(&code);
+        let cache_item = SharedCache::find_jump_and_sub_destinations(&code);
 
         // then
-    assert!(valid_jump_destinations.contains(66));
+        assert!(cache_item
+            .jump_destination
+            .0
+            .iter()
+            .eq(vec![66].into_iter()));
+        assert!(cache_item.sub_entrypoint.0.is_empty());
+    }
+
+    #[test]
+    fn test_find_jump_destinations_not_in_data_segments() {
+        // given
+
+        // 0000 60 06   PUSH1 06
+        // 0002 56      JUMP
+        // 0003 50 5B   PUSH1 0x5B
+        // 0005 56      STOP
+        // 0006 5B      JUMPDEST
+        // 0007 60 04   PUSH1 04
+        // 0009 56      JUMP
+        let code = hex!("600656605B565B6004");
+
+        // when
+        let cache_item = SharedCache::find_jump_and_sub_destinations(&code);
+
+        // then
+        assert!(cache_item.jump_destination.0.iter().eq(vec![6].into_iter()));
+        assert!(cache_item.sub_entrypoint.0.is_empty());
+    }
+
+    #[test]
+    fn test_find_sub_entrypoints() {
+        // given
+
+        // see https://eips.ethereum.org/EIPS/eip-2315 for disassembly
+        let code = hex!("6800000000000000000c5e005c60115e5d5c5d");
+
+        // when
+        let cache_item = SharedCache::find_jump_and_sub_destinations(&code);
+
+        // then
+        assert!(cache_item.jump_destination.0.is_empty());
+        assert!(cache_item
+            .sub_entrypoint
+            .0
+            .iter()
+            .eq(vec![12, 17].into_iter()));
+    }
+
+    #[test]
+    fn test_find_jump_and_sub_allowing_unknown_opcodes() {
+        // precondition
+        assert!(Instruction::from_u8(0xcc) == None);
+
+        // given
+
+        // 0000 5B   JUMPDEST
+        // 0001 CC   ???
+        // 0002 5C   BEGINSUB
+        let code = hex!("5BCC5C");
+
+        // when
+        let cache_item = SharedCache::find_jump_and_sub_destinations(&code);
+
+        // then
+        assert!(cache_item.jump_destination.0.iter().eq(vec![0].into_iter()));
+        assert!(cache_item.sub_entrypoint.0.iter().eq(vec![2].into_iter()));
+    }
 }

ethcore/evm/src/tests.rs

@@ -14,6 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Parity Ethereum.  If not, see <http://www.gnu.org/licenses/>.
 
+use super::interpreter::MAX_SUB_STACK_SIZE;
 use ethereum_types::{Address, H256, U256};
 use factory::Factory;
 use hex_literal::hex;
@@ -1037,6 +1038,171 @@ fn test_jumps(factory: super::Factory) {
     assert_eq!(gas_left, U256::from(54_117));
 }
 
+evm_test! {test_subs_simple: test_subs_simple_int}
+fn test_subs_simple(factory: super::Factory) {
+    // as defined in https://eips.ethereum.org/EIPS/eip-2315
+    let code = hex!("60045e005c5d").to_vec();
+
+    let mut params = ActionParams::default();
+    params.gas = U256::from(18);
+    params.code = Some(Arc::new(code));
+    let mut ext = FakeExt::new_berlin();
+
+    let gas_left = {
+        let vm = factory.create(params, ext.schedule(), ext.depth());
+        test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
+    };
+
+    assert_eq!(gas_left, U256::from(0));
+}
+
+evm_test! {test_subs_two_levels: test_subs_two_levels_int}
+fn test_subs_two_levels(factory: super::Factory) {
+    // as defined in https://eips.ethereum.org/EIPS/eip-2315
+    let code = hex!("6800000000000000000c5e005c60115e5d5c5d").to_vec();
+
+    let mut params = ActionParams::default();
+    params.gas = U256::from(36);
+    params.code = Some(Arc::new(code));
+    let mut ext = FakeExt::new_berlin();
+
+    let gas_left = {
+        let vm = factory.create(params, ext.schedule(), ext.depth());
+        test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
+    };
+
+    assert_eq!(gas_left, U256::from(0));
+}
+
+evm_test! {test_subs_invalid_jump: test_subs_invalid_jump_int}
+fn test_subs_invalid_jump(factory: super::Factory) {
+    // as defined in https://eips.ethereum.org/EIPS/eip-2315
+    let code = hex!("6801000000000000000c5e005c60115e5d5c5d").to_vec();
+
+    let mut params = ActionParams::default();
+    params.gas = U256::from(24);
+    params.code = Some(Arc::new(code));
+    let mut ext = FakeExt::new_berlin();
+
+    let current = {
+        let vm = factory.create(params, ext.schedule(), ext.depth());
+        test_finalize(vm.exec(&mut ext).ok().unwrap())
+    };
+
+    let expected = Result::Err(vm::Error::BadJumpDestination { destination: 0xc });
+    assert_eq!(current, expected);
+}
+
+evm_test! {test_subs_shallow_return_stack: test_subs_shallow_return_stack_int}
+fn test_subs_shallow_return_stack(factory: super::Factory) {
+    // as defined in https://eips.ethereum.org/EIPS/eip-2315
+    let code = hex!("5d5858").to_vec();
+
+    let mut params = ActionParams::default();
+    params.gas = U256::from(24);
+    params.code = Some(Arc::new(code));
+    let mut ext = FakeExt::new_berlin();
+
+    let current = {
+        let vm = factory.create(params, ext.schedule(), ext.depth());
+        test_finalize(vm.exec(&mut ext).ok().unwrap())
+    };
+
+    let expected = Result::Err(vm::Error::SubStackUnderflow {
+        wanted: 1,
+        on_stack: 0,
+    });
+    assert_eq!(current, expected);
+}
+
+evm_test! {test_subs_substack_limit: test_subs_substack_limit_int}
+fn test_subs_substack_limit(factory: super::Factory) {
+    //    PUSH <recursion_limit>
+    //    JUMP a
+    // s: BEGINSUB
+    // a: JUMPDEST
+    //    DUP1
+    //    JUMPI c
+    //    STOP
+    // c: JUMPDEST
+    //    PUSH1 1
+    //    SWAP
+    //    SUB
+    //    JUMPSUB s
+
+    let mut code = hex!("6104006007565c5b80600d57005b6001900360065e").to_vec();
+    code[1..3].copy_from_slice(&(MAX_SUB_STACK_SIZE as u16).to_be_bytes()[..]);
+
+    let mut params = ActionParams::default();
+    params.gas = U256::from(1_000_000);
+    params.code = Some(Arc::new(code));
+    let mut ext = FakeExt::new_berlin();
+
+    let gas_left = {
+        let vm = factory.create(params, ext.schedule(), ext.depth());
+        test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
+    };
+
+    assert_eq!(gas_left, U256::from(959_049));
+}
+
+evm_test! {test_subs_substack_out: test_subs_substack_out_int}
+fn test_subs_substack_out(factory: super::Factory) {
+    let mut code = hex!("6104006007565c5b80600d57005b6001900360065e").to_vec();
+    code[1..3].copy_from_slice(&((MAX_SUB_STACK_SIZE + 1) as u16).to_be_bytes()[..]);
+
+    let mut params = ActionParams::default();
+    params.gas = U256::from(1_000_000);
+    params.code = Some(Arc::new(code));
+    let mut ext = FakeExt::new_berlin();
+
+    let current = {
+        let vm = factory.create(params, ext.schedule(), ext.depth());
+        test_finalize(vm.exec(&mut ext).ok().unwrap())
+    };
+
+    let expected = Result::Err(vm::Error::OutOfSubStack {
+        wanted: 1,
+        limit: MAX_SUB_STACK_SIZE,
+    });
+    assert_eq!(current, expected);
+}
+
+evm_test! {test_subs_sub_at_end: test_subs_sub_at_end_int}
+fn test_subs_sub_at_end(factory: super::Factory) {
+    let code = hex!("6005565c5d5b60035e").to_vec();
+
+    let mut params = ActionParams::default();
+    params.gas = U256::from(30);
+    params.code = Some(Arc::new(code));
+    let mut ext = FakeExt::new_berlin();
+
+    let gas_left = {
+        let vm = factory.create(params, ext.schedule(), ext.depth());
+        test_finalize(vm.exec(&mut ext).ok().unwrap()).unwrap()
+    };
+
+    assert_eq!(gas_left, U256::from(0));
+}
+
+evm_test! {test_subs_walk_into_subroutine: test_subs_walk_into_subroutine_int}
+fn test_subs_walk_into_subroutine(factory: super::Factory) {
+    let code = hex!("5c5d00").to_vec();
+
+    let mut params = ActionParams::default();
+    params.gas = U256::from(100);
+    params.code = Some(Arc::new(code));
+    let mut ext = FakeExt::new_berlin();
+
+    let current = {
+        let vm = factory.create(params, ext.schedule(), ext.depth());
+        test_finalize(vm.exec(&mut ext).ok().unwrap())
+    };
+
+    let expected = Result::Err(vm::Error::InvalidSubEntry);
+    assert_eq!(current, expected);
+}
+
 evm_test! {test_calls: test_calls_int}
 fn test_calls(factory: super::Factory) {
     let code = "600054602d57600160005560006000600060006050610998610100f160006000600060006050610998610100f25b".from_hex().unwrap();

ethcore/src/executive.rs

@@ -435,6 +435,9 @@ impl<'a> CallCreateExecutive<'a> {
             | Err(vm::Error::MutableCallInStaticContext)
             | Err(vm::Error::OutOfBounds)
             | Err(vm::Error::Reverted)
+            | Err(vm::Error::SubStackUnderflow { .. })
+            | Err(vm::Error::OutOfSubStack { .. })
+            | Err(vm::Error::InvalidSubEntry)
             | Ok(FinalizationResult {
                 apply_state: false, ..
             }) => {

ethcore/src/spec/spec.rs

@@ -126,6 +126,8 @@ pub struct CommonParams {
     pub eip1884_transition: BlockNumber,
     /// Number of first block where EIP-2028 rules begin.
     pub eip2028_transition: BlockNumber,
+    /// Number of first block where EIP-2315 rules begin.
+    pub eip2315_transition: BlockNumber,
     /// Number of first block where dust cleanup rules (EIP-168 and EIP169) begin.
     pub dust_protection_transition: BlockNumber,
     /// Nonce cap increase per block. Nonce cap is only checked if dust protection is enabled.
@@ -197,6 +199,7 @@ impl CommonParams {
             && !(block_number >= self.eip1283_disable_transition))
             || block_number >= self.eip1283_reenable_transition;
         schedule.eip1706 = block_number >= self.eip1706_transition;
+        schedule.have_subs = block_number >= self.eip2315_transition;
 
         if block_number >= self.eip1884_transition {
             schedule.have_selfbalance = true;
@@ -329,6 +332,9 @@ impl From<ethjson::spec::Params> for CommonParams {
             eip2028_transition: p
                 .eip2028_transition
                 .map_or_else(BlockNumber::max_value, Into::into),
+            eip2315_transition: p
+                .eip2315_transition
+                .map_or_else(BlockNumber::max_value, Into::into),
             dust_protection_transition: p
                 .dust_protection_transition
                 .map_or_else(BlockNumber::max_value, Into::into),

ethcore/src/trace/types/error.rs

@@ -34,6 +34,12 @@ pub enum Error {
     StackUnderflow,
     /// When execution would exceed defined Stack Limit
     OutOfStack,
+    /// When there is not enough subroutine stack elements to return from
+    SubStackUnderflow,
+    /// When execution would exceed defined subroutine Stack Limit
+    OutOfSubStack,
+    /// When the code walks into a subroutine, that is not allowed
+    InvalidSubEntry,
     /// When builtin contract failed on input data
     BuiltIn,
     /// Returned on evm internal error. Should never be ignored during development.
@@ -57,6 +63,9 @@ impl<'a> From<&'a VmError> for Error {
             VmError::BadInstruction { .. } => Error::BadInstruction,
             VmError::StackUnderflow { .. } => Error::StackUnderflow,
             VmError::OutOfStack { .. } => Error::OutOfStack,
+            VmError::SubStackUnderflow { .. } => Error::SubStackUnderflow,
+            VmError::OutOfSubStack { .. } => Error::OutOfSubStack,
+            VmError::InvalidSubEntry { .. } => Error::InvalidSubEntry,
             VmError::BuiltIn { .. } => Error::BuiltIn,
             VmError::Wasm { .. } => Error::Wasm,
             VmError::Internal(_) => Error::Internal,
@@ -82,7 +91,10 @@ impl fmt::Display for Error {
             BadInstruction => "Bad instruction",
             StackUnderflow => "Stack underflow",
             OutOfStack => "Out of stack",
+            SubStackUnderflow => "Subroutine stack underflow",
+            OutOfSubStack => "Subroutine stack overflow",
             BuiltIn => "Built-in failed",
+            InvalidSubEntry => "Invalid subroutine entry",
             Wasm => "Wasm runtime error",
             Internal => "Internal error",
             MutableCallInStaticContext => "Mutable Call In Static Context",
@@ -108,6 +120,9 @@ impl Encodable for Error {
             Wasm => 8,
             OutOfBounds => 9,
             Reverted => 10,
+            SubStackUnderflow => 11,
+            OutOfSubStack => 12,
+            InvalidSubEntry => 13,
         };
 
         s.append_internal(&value);
@@ -130,6 +145,9 @@ impl Decodable for Error {
             8 => Ok(Wasm),
             9 => Ok(OutOfBounds),
             10 => Ok(Reverted),
+            11 => Ok(SubStackUnderflow),
+            12 => Ok(OutOfSubStack),
+            13 => Ok(InvalidSubEntry),
             _ => Err(DecoderError::Custom("Invalid error type")),
         }
     }

ethcore/vm/src/error.rs

@@ -72,6 +72,22 @@ pub enum Error {
         /// What was the stack limit
         limit: usize,
     },
+    /// When there is not enough subroutine stack elements to return from
+    SubStackUnderflow {
+        /// How many stack elements was requested by instruction
+        wanted: usize,
+        /// How many elements were on stack
+        on_stack: usize,
+    },
+    /// When execution would exceed defined subroutine Stack Limit
+    OutOfSubStack {
+        /// How many stack elements instruction wanted to pop
+        wanted: usize,
+        /// What was the stack limit
+        limit: usize,
+    },
+    /// When the code walks into a subroutine, that is not allowed
+    InvalidSubEntry,
     /// Built-in contract failed on given input
     BuiltIn(&'static str),
     /// When execution tries to modify the state in static context
@@ -103,9 +119,11 @@ impl fmt::Display for Error {
         use self::Error::*;
         match *self {
             OutOfGas => write!(f, "Out of gas"),
-            BadJumpDestination { destination } => {
+            BadJumpDestination { destination } => write!(
-                write!(f, "Bad jump destination {:x}", destination)
+                f,
-            }
+                "Bad jump destination {:x}  (trimmed to usize)",
+                destination
+            ),
             BadInstruction { instruction } => write!(f, "Bad instruction {:x}", instruction),
             StackUnderflow {
                 instruction,
@@ -117,6 +135,13 @@ impl fmt::Display for Error {
                 wanted,
                 limit,
             } => write!(f, "Out of stack {} {}/{}", instruction, wanted, limit),
+            SubStackUnderflow { wanted, on_stack } => {
+                write!(f, "Subroutine stack underflow {}/{}", wanted, on_stack)
+            }
+            OutOfSubStack { wanted, limit } => {
+                write!(f, "Out of subroutine stack {}/{}", wanted, limit)
+            }
+            InvalidSubEntry => write!(f, "Invalid subroutine entry"),
             BuiltIn(name) => write!(f, "Built-in failed: {}", name),
             Internal(ref msg) => write!(f, "Internal error: {}", msg),
             MutableCallInStaticContext => write!(f, "Mutable call in static context"),

ethcore/vm/src/schedule.rs

@@ -120,6 +120,8 @@ pub struct Schedule {
     pub have_chain_id: bool,
     /// SELFBALANCE opcode enabled.
     pub have_selfbalance: bool,
+    /// BEGINSUB, JUMPSUB and RETURNSUB opcodes enabled.
+    pub have_subs: bool,
     /// Kill basic accounts below this balance if touched.
     pub kill_dust: CleanDustMode,
     /// Enable EIP-1283 rules
@@ -224,6 +226,7 @@ impl Schedule {
             have_bitwise_shifting: false,
             have_chain_id: false,
             have_selfbalance: false,
+            have_subs: false,
             have_extcodehash: false,
             stack_limit: 1024,
             max_depth: 1024,
@@ -303,6 +306,13 @@ impl Schedule {
         schedule
     }
 
+    /// Schedule for the Berlin fork of the Ethereum main net.
+    pub fn new_berlin() -> Schedule {
+        let mut schedule = Self::new_istanbul();
+        schedule.have_subs = true; // EIP 2315
+        schedule
+    }
+
     fn new(efcd: bool, hdc: bool, tcg: usize) -> Schedule {
         Schedule {
             exceptional_failed_code_deposit: efcd,
@@ -313,6 +323,7 @@ impl Schedule {
             have_bitwise_shifting: false,
             have_chain_id: false,
             have_selfbalance: false,
+            have_subs: false,
             have_extcodehash: false,
             stack_limit: 1024,
             max_depth: 1024,

ethcore/vm/src/tests.rs

@@ -115,6 +115,13 @@ impl FakeExt {
         ext
     }
 
+    /// New fake externalities with Berlin schedule rules
+    pub fn new_berlin() -> Self {
+        let mut ext = FakeExt::default();
+        ext.schedule = Schedule::new_berlin();
+        ext
+    }
+
     /// Alter fake externalities to allow wasm
     pub fn with_wasm(mut self) -> Self {
         self.schedule.wasm = Some(Default::default());

json/src/spec/params.rs

@@ -104,6 +104,8 @@ pub struct Params {
     /// See `CommonParams` docs.
     pub eip2028_transition: Option<Uint>,
     /// See `CommonParams` docs.
+    pub eip2315_transition: Option<Uint>,
+    /// See `CommonParams` docs.
     pub dust_protection_transition: Option<Uint>,
     /// See `CommonParams` docs.
     pub nonce_cap_increment: Option<Uint>,