Add contract creation flag (#1056)

* Add contract creation flag

* Minor

* Fix intrinsic gas test

evm/src/cpu/kernel/asm/core/process_txn.asm

@@ -407,5 +407,5 @@ contract_creation_fault_4:
     JUMP
 
 
-invalid_txn:
+global invalid_txn:
     %jump(txn_loop)

evm/src/cpu/kernel/asm/core/util.asm

@@ -21,11 +21,7 @@
 // Returns whether the current transaction is a contract creation transaction.
 %macro is_contract_creation
     // stack: (empty)
-    %mload_txn_field(@TXN_FIELD_TO)
-    // stack: to
-    ISZERO
-    // If there is no "to" field, then this is a contract creation.
-    // stack: to == 0
+    %mload_global_metadata(@GLOBAL_METADATA_CONTRACT_CREATION)
 %endmacro
 
 %macro is_precompile

evm/src/cpu/kernel/asm/rlp/decode.asm

@@ -130,7 +130,7 @@ decode_rlp_list_len_big:
 // fit in a single (256-bit) word on the stack.
 // Pre stack: pos, len, retdest
 // Post stack: pos', int
-decode_int_given_len:
+global decode_int_given_len:
     %stack (pos, len, retdest) -> (pos, len, pos, retdest)
     ADD
     // stack: end_pos, pos, retdest

evm/src/cpu/kernel/asm/transactions/common_decoding.asm

@@ -61,12 +61,30 @@
 %endmacro
 
 // Decode the "to" field and store it.
+// This field is either 160-bit or empty in the case of a contract creation txn.
 %macro decode_and_store_to
     // stack: pos
-    %decode_rlp_scalar
-    %stack (pos, to) -> (to, pos)
+    %decode_rlp_string_len
+    // stack: pos, len
+    SWAP1
+    // stack: len, pos
+    DUP1 ISZERO %jumpi(%%contract_creation)
+    // stack: len, pos
+    DUP1 %eq_const(20) ISZERO %jumpi(invalid_txn) // Address is 160-bit
+    %stack (len, pos) -> (pos, len, %%with_scalar)
+    %jump(decode_int_given_len)
+%%with_scalar:
+    // stack: pos, int
+    SWAP1
     %mstore_txn_field(@TXN_FIELD_TO)
     // stack: pos
+    %jump(%%end)
+%%contract_creation:
+    // stack: len, pos
+    POP
+    PUSH 1 %mstore_global_metadata(@GLOBAL_METADATA_CONTRACT_CREATION)
+    // stack: pos
+%%end:
 %endmacro
 
 // Decode the "value" field and store it.

evm/src/cpu/kernel/asm/transactions/type_0.asm

@@ -102,13 +102,13 @@ type_0_compute_signed_data:
     // stack: rlp_pos, rlp_start, retdest
 
     %mload_txn_field(@TXN_FIELD_TO)
-    DUP1 %jumpi(nonzero_to)
-    // stack: to, rlp_pos, rlp_start, retdest
-    SWAP1 %encode_rlp_scalar
-    %jump(after_to)
-nonzero_to:
+    %mload_global_metadata(@GLOBAL_METADATA_CONTRACT_CREATION) %jumpi(zero_to)
     // stack: to, rlp_pos, rlp_start, retdest
     SWAP1 %encode_rlp_160
+    %jump(after_to)
+zero_to:
+    // stack: to, rlp_pos, rlp_start, retdest
+    SWAP1 %encode_rlp_scalar
     // stack: rlp_pos, rlp_start, retdest
 
 after_to:

evm/src/cpu/kernel/asm/transactions/type_1.asm

@@ -57,13 +57,13 @@ type_1_compute_signed_data:
     // stack: rlp_pos, rlp_start, retdest
 
     %mload_txn_field(@TXN_FIELD_TO)
-    DUP1 %jumpi(nonzero_to)
-    // stack: to, rlp_pos, rlp_start, retdest
-    SWAP1 %encode_rlp_scalar
-    %jump(after_to)
-nonzero_to:
+    %mload_global_metadata(@GLOBAL_METADATA_CONTRACT_CREATION) %jumpi(zero_to)
     // stack: to, rlp_pos, rlp_start, retdest
     SWAP1 %encode_rlp_160
+    %jump(after_to)
+zero_to:
+    // stack: to, rlp_pos, rlp_start, retdest
+    SWAP1 %encode_rlp_scalar
     // stack: rlp_pos, rlp_start, retdest
 
 after_to:

evm/src/cpu/kernel/asm/transactions/type_2.asm

@@ -64,13 +64,13 @@ type_2_compute_signed_data:
     // stack: rlp_pos, rlp_start, retdest
 
     %mload_txn_field(@TXN_FIELD_TO)
-    DUP1 %jumpi(nonzero_to)
-    // stack: to, rlp_pos, rlp_start, retdest
-    SWAP1 %encode_rlp_scalar
-    %jump(after_to)
-nonzero_to:
+    %mload_global_metadata(@GLOBAL_METADATA_CONTRACT_CREATION) %jumpi(zero_to)
     // stack: to, rlp_pos, rlp_start, retdest
     SWAP1 %encode_rlp_160
+    %jump(after_to)
+zero_to:
+    // stack: to, rlp_pos, rlp_start, retdest
+    SWAP1 %encode_rlp_scalar
     // stack: rlp_pos, rlp_start, retdest
 
 after_to:

evm/src/cpu/kernel/constants/global_metadata.rs

@@ -65,10 +65,12 @@ pub(crate) enum GlobalMetadata {
     AccessListRlpStart = 31,
     // Length of the access list in the RLP for type-1 txns.
     AccessListRlpLen = 32,
+    // Boolean flag indicating if the txn is a contract creation txn.
+    ContractCreation = 33,
 }
 
 impl GlobalMetadata {
-    pub(crate) const COUNT: usize = 32;
+    pub(crate) const COUNT: usize = 33;
 
     pub(crate) fn all() -> [Self; Self::COUNT] {
         [
@@ -104,6 +106,7 @@ impl GlobalMetadata {
             Self::AccessListDataCost,
             Self::AccessListRlpStart,
             Self::AccessListRlpLen,
+            Self::ContractCreation,
         ]
     }
 
@@ -142,6 +145,7 @@ impl GlobalMetadata {
             Self::AccessListDataCost => "GLOBAL_METADATA_ACCESS_LIST_DATA_COST",
             Self::AccessListRlpStart => "GLOBAL_METADATA_ACCESS_LIST_RLP_START",
             Self::AccessListRlpLen => "GLOBAL_METADATA_ACCESS_LIST_RLP_LEN",
+            Self::ContractCreation => "GLOBAL_METADATA_CONTRACT_CREATION",
         }
     }
 }

evm/src/cpu/kernel/tests/core/intrinsic_gas.rs

@@ -1,6 +1,8 @@
 use anyhow::Result;
+use ethereum_types::U256;
 
 use crate::cpu::kernel::aggregator::KERNEL;
+use crate::cpu::kernel::constants::global_metadata::GlobalMetadata;
 use crate::cpu::kernel::constants::txn_fields::NormalizedTxnField;
 use crate::cpu::kernel::interpreter::Interpreter;
 
@@ -14,6 +16,7 @@ fn test_intrinsic_gas() -> Result<()> {
     // Contract creation transaction.
     let initial_stack = vec![0xdeadbeefu32.into()];
     let mut interpreter = Interpreter::new_with_kernel(intrinsic_gas, initial_stack.clone());
+    interpreter.set_global_metadata_field(GlobalMetadata::ContractCreation, U256::one());
     interpreter.run()?;
     assert_eq!(interpreter.stack(), vec![(GAS_TX + GAS_TXCREATE).into()]);