From 6edd589138b082a92d7e9c4d24ee0a6df34ee1e0 Mon Sep 17 00:00:00 2001
From: wborgeaud <williamborgeaud@gmail.com>
Date: Thu, 20 Apr 2023 07:00:15 +0200
Subject: [PATCH] Gas and more for `CREATE(2)` (#995)

* Gas

* Codehash

* Minor
---
 evm/src/cpu/kernel/asm/core/create.asm     | 70 ++++++++++++++++++++--
 evm/src/cpu/kernel/asm/memory/metadata.asm |  9 +++
 2 files changed, 74 insertions(+), 5 deletions(-)

diff --git a/evm/src/cpu/kernel/asm/core/create.asm b/evm/src/cpu/kernel/asm/core/create.asm
index 866e482c..573d1348 100644
--- a/evm/src/cpu/kernel/asm/core/create.asm
+++ b/evm/src/cpu/kernel/asm/core/create.asm
@@ -5,8 +5,13 @@
 // Post stack: address
 global sys_create:
     %check_static
+
+    %stack (kexit_info, value, code_offset, code_len) -> (code_len, code_offset, kexit_info, value, code_offset, code_len)
+    %checked_mem_expansion
     // stack: kexit_info, value, code_offset, code_len
-    // TODO: Charge gas.
+    %charge_gas_const(@GAS_CREATE)
+    // TODO: If using EIP-3860, we should limit and charge gas on `code_len`.
+
     %stack (kexit_info, value, code_offset, code_len)
         -> (sys_create_got_address, value, code_offset, code_len, kexit_info)
     %address
@@ -27,8 +32,15 @@ sys_create_got_address:
 // Post stack: address
 global sys_create2:
     %check_static
+
     // stack: kexit_info, value, code_offset, code_len, salt
-    // TODO: Charge gas.
+    %stack (kexit_info, value, code_offset, code_len) -> (code_len, code_offset, kexit_info, value, code_offset, code_len)
+    %checked_mem_expansion
+    // stack: kexit_info, value, code_offset, code_len, salt
+    DUP4 %num_bytes_to_num_words
+    %mul_const(@GAS_KECCAK256WORD) %add_const(@GAS_CREATE) %charge_gas
+    // TODO: If using EIP-3860, we should limit and charge gas on `code_len`.
+
     SWAP4
     %stack (salt) -> (salt, create_common)
     // stack: salt, create_common, value, code_offset, code_len, kexit_info
@@ -78,7 +90,10 @@ global create_common:
     GET_CONTEXT
     // stack: src_ctx, new_ctx, address, value, code_offset, code_len, kexit_info
 
-    // Copy the code from txdata to the new context's code segment.
+    %stack (src_ctx, new_ctx, address, value, code_offset, code_len) ->
+        (code_len, new_ctx, src_ctx, new_ctx, address, value, code_offset, code_len)
+    %set_new_ctx_code_size POP
+    // Copy the code from memory to the new context's code segment.
     %stack (src_ctx, new_ctx, address, value, code_offset, code_len)
         -> (new_ctx, @SEGMENT_CODE, 0, // DST
             src_ctx, @SEGMENT_MAIN_MEMORY, code_offset, // SRC
@@ -113,7 +128,32 @@ after_constructor:
     // stack: success, leftover_gas, new_ctx, address, kexit_info
     SWAP2
     // stack: new_ctx, leftover_gas, success, address, kexit_info
-    POP // TODO: Ignoring new_ctx for now, but we will need it to store code that was returned, if any.
+    POP
+
+    // TODO: EIP-170: Contract code size limit.
+    // TODO: EIP-3541: Reject new contract code starting with the 0xEF byte
+
+    // TODO: Skip blocks below if success is false.
+    // Charge gas for the code size.
+    SWAP3
+    // stack: kexit_info, success, address, leftover_gas
+    %returndatasize // Size of the code.
+    %mul_const(@GAS_CODEDEPOSIT) %charge_gas
+    SWAP3
+
+    // Store the code hash of the new contract.
+    GET_CONTEXT
+    %returndatasize
+    %stack (size, ctx) -> (ctx, @SEGMENT_RETURNDATA, 0, size) // context, segment, offset, len
+    KECCAK_GENERAL
+    // stack: codehash, leftover_gas, success, address, kexit_info
+    DUP4
+    // stack: address, codehash, leftover_gas, success, address, kexit_info
+    %set_codehash
+
+    // Set the return data size to 0.
+    %mstore_context_metadata(@CTX_METADATA_RETURNDATA_SIZE, 0)
+
     // stack: leftover_gas, success, address, kexit_info
     %shl_const(192)
     // stack: leftover_gas << 192, success, address, kexit_info
@@ -123,6 +163,26 @@ after_constructor:
     // stack: address_if_success, leftover_gas << 192, kexit_info
     SWAP2
     // stack: kexit_info, leftover_gas << 192, address_if_success
-    ADD
+    SUB
     // stack: kexit_info, address_if_success
     EXIT_KERNEL
+
+%macro set_codehash
+    %stack (addr, codehash) -> (addr, codehash, %%after)
+    %jump(set_codehash)
+%%after:
+    // stack: (empty)
+%endmacro
+
+// Pre stack: addr, codehash, redest
+// Post stack: (empty)
+// TODO: Should it be copy-on-write (with make_account_copy) instead of mutating the trie?
+set_codehash:
+    // stack: addr, codehash, retdest
+    %mpt_read_state_trie
+    // stack: account_ptr, codehash, retdest
+    %add_const(3)
+    // stack: codehash_ptr, codehash, retdest
+    %mstore_trie_data
+    // stack: retdest
+    JUMP
diff --git a/evm/src/cpu/kernel/asm/memory/metadata.asm b/evm/src/cpu/kernel/asm/memory/metadata.asm
index c158718b..42a88957 100644
--- a/evm/src/cpu/kernel/asm/memory/metadata.asm
+++ b/evm/src/cpu/kernel/asm/memory/metadata.asm
@@ -34,6 +34,15 @@
     // stack: (empty)
 %endmacro
 
+// Store the given context metadata field to memory.
+%macro mstore_context_metadata(field, value)
+    PUSH $value
+    PUSH $field
+    // stack: offset, value
+    %mstore_current(@SEGMENT_CONTEXT_METADATA)
+    // stack: (empty)
+%endmacro
+
 %macro mstore_parent_context_metadata(field)
     // stack: value
     %mload_context_metadata(@CTX_METADATA_PARENT_CONTEXT)