integrate evmc 'getCodeHash'

nimbus/vm/computation.nim

@@ -96,7 +96,17 @@ template getCodeSize*(c: Computation, address: EthAddress): uint =
   when evmc_enabled:
     c.host.getCodeSize(address)
   else:
-    uint(c.vmState.readOnlyStateDB.getCode(account).len)
+    uint(c.vmState.readOnlyStateDB.getCode(address).len)
+
+template getCodeHash*(c: Computation, address: EthAddress): Hash256 =
+  when evmc_enabled:
+    c.host.getCodeHash(address)
+  else:
+    let db = c.vmState.readOnlyStateDB
+    if not db.accountExists(address) or db.isEmptyAccount(address):
+      default(Hash256)
+    else:
+      db.getCodeHash(address)
 
 proc newComputation*(vmState: BaseVMState, message: Message): Computation =
   new result

nimbus/vm/evmc_api.nim

@@ -71,7 +71,8 @@ proc getCodeSize*(ctx: HostContext, address: EthAddress): uint =
 
 proc getCodeHash*(ctx: HostContext, address: EthAddress): Hash256 =
   var address = toEvmc(address)
-  Hash256.fromEvmc ctx.host.get_code_hash(ctx.context, address.addr)
+  {.gcsafe.}:
+    Hash256.fromEvmc ctx.host.get_code_hash(ctx.context, address.addr)
 
 proc copyCode*(ctx: HostContext, address: EthAddress, codeOffset: int = 0): seq[byte] =
   let size = ctx.getCodeSize(address).int

nimbus/vm/evmc_host.nim

@@ -80,7 +80,17 @@ proc hostGetCodeSizeImpl(ctx: Computation, address: var evmc_address): uint {.cd
   ctx.vmState.readOnlyStateDB.getCode(fromEvmc(address)).len.uint
 
 proc hostGetCodeHashImpl(ctx: Computation, address: var evmc_address): evmc_bytes32 {.cdecl.} =
-  ctx.vmstate.readOnlyStateDB.getCodeHash(fromEvmc(address)).toEvmc()
+  let
+    db = ctx.vmstate.readOnlyStateDB
+    address = fromEvmc(address)
+
+  if not db.accountExists(address):
+    return
+
+  if db.isEmptyAccount(address):
+    return
+
+  db.getCodeHash(address).toEvmc()
 
 proc hostCopyCodeImpl(ctx: Computation, address: var evmc_address,
                       codeOffset: uint, bufferData: ptr byte,

nimbus/vm/interpreter/opcodes_impl.nim

@@ -904,17 +904,7 @@ op sarOp, inline = true:
 
 op extCodeHash, inline = true:
   let address = c.stack.popAddress()
-  # this is very inefficient, it calls underlying
-  # database too much, we can reduce it by implementing accounts
-  # cache
-  if not c.accountExists(address):
-    push: 0
-    return
-
-  if c.vmState.readOnlyStateDB.isEmptyAccount(address):
-    push: 0
-  else:
-    push: c.vmState.readOnlyStateDB.getCodeHash(address)
+  push: c.getCodeHash(address)
 
 op sstoreEIP2200, inline = false, slot, value:
   checkInStaticContext(c)