This fixes#867 "EIP-170 related consensus error at Goerli block 5080941", and
equivalent on other networks.
This combines a change on the EVM-caller side with an EVM-side change from
@jangko 6548ff98 "fixes CREATE/CREATE2's `returndata` bug", making the caller
EVM ignore any data except from `REVERT`.
Either change works by itself. The reason for both is to ensure we definitely
comply with ambiguous EVMC expectations from either side of that boundary, and
it makes the internal API clearer.
As well as fixing a specific consensus issue, there are some other EVM logic
changes too: Refactored `writeContract`, how `RETURNDATA` is handled inside the
EVM, and changed behaviour with quirks before EIP-2 (Homestead).
The fix allows sync to pass block 5080941 on Goerli, and probably equivalent on
other networks. Here's a trace at batch 5080897..5081088:
```
TRC 2021-10-01 21:18:12.883+01:00 Persisting blocks file=persist_blocks.nim:43 fromBlock=5080897 toBlock=5081088
...
DBG 2021-10-01 21:18:13.270+01:00 Contract code size exceeds EIP170 topics="vm computation" file=computation.nim:236 limit=24577 actual=31411
DBG 2021-10-01 21:18:13.271+01:00 gasUsed neq cumulativeGasUsed file=process_block.nim:68 block=5080941/0A3537BC5BDFC637349E1C77D9648F2F65E2BF973ABF7956618F854B769DF626 gasUsed=3129669 cumulativeGasUsed=3132615
TRC 2021-10-01 21:18:13.271+01:00 peer disconnected file=blockchain_sync.nim:407 peer=<IP:PORT>
```
Although it says "Contract code size" and "gasUsed", this bug is more general
than either contract size or gas. It's due to incorrect behaviour of EVM
instructions `RETURNDATA` and `RETURNDATASIZE`.
Sometimes when `writeContract` decides to reject writing the contract for any
of several reasons (for example just insufficient gas), the unwritten contract
code was being used as the "return data", and given to the caller. If the
caller used `RETURNDATA` or `RETURNDATASIZE` ops, those incorrectly reported
the contract code that didn't get written.
EIP-211 (https://eips.ethereum.org/EIPS/eip-211) describes `RETURNDATA`:
> "`CREATE` and `CREATE2` are considered to return the empty buffer in the
> success case and the failure data in the failure case".
The language is ambiguous. In fact "failure case" means when the contract uses
`REVERT` to finish. It doesn't mean other failures like out of gas, EIP-170
limit, EIP-3541, etc.
To be thorough, and to ensure we always do the right thing with real EVMC when
that's finalised, this patch fixes the `RETURNDATA` issue in two places, either
of which make Goerli block 5080941 pass.
`writeContract` has been refactored to be caller, and so has where it's called.
It sets an error in the usual way if contract writing is rejected -- that's
anticipating EVMC, where we'll use different error codes later.
Overall four behaviour changes:
1. On the callee side, it doesn't set `c.outputData` except for `REVERT`.
2. On the caller side, it doesn't read `child.outputData` except for `REVERT`.
3. There was a bug in processing before Homestead fork (EIP-2). We did not
match the spec or other implementations; now we do. When there's
insufficient gas, before Homestead it's treated as success but with an empty
contract.
d117c8f3fd/ethereum/processblock.py (L304)https://github.com/ethereum/go-ethereum/blob/401354976bb4/core/vm/instructions.go#L586
4. The Byzantium check has been removed, as it's unnecessary.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
As this branch of vm2 doesn't support EVMC, this EVMC-motivated change is only
required here for internal compatibility.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
Disable some trace messages which appeared a lot in the output and probably
aren't so useful any more, when block processing is functioning well at high
speed.
Turning on the trace level globally is useful to get a feel for what's
happening, but only if each category is kept to a reasonable amount.
As well as overwhelming the output so that it's hard to see general activity,
some of these messages happen so much they severely slow down processing. Ones
called every time an EVM opcode uses some gas are particularly extreme.
These messages have all been chosen as things which are probably not useful any
more (the relevant functionality has been debugged and is tested plenty).
These have been commented out rather than removed. It may be that turning
trace topics on/off, or other selection, is a better longer term solution, but
that will require better command line options and good defaults for sure.
(I think higher levels `tracev` and `tracevv` levels (extra verbose) would be
more useful for this sort of deep tracing on request.)
For now, enabling `--log-level:TRACE` on the command line is quite useful as
long as we keep each category reasonable, and this patch tries to keep that
balance.
- Don't show "has transactions" on virtually every block imported.
- Don't show "Sender" and "txHash" lines on every transaction processed.
- Don't show "GAS CONSUMPTION" on every opcode executed", this is way too much.
- Don't show "GAS RETURNED" and "GAS REFUND" on each contract call.
- Don't show "op: Stop" on every Stop opcode, which means every transaction.
- Don't show "Insufficient funds" whenever a contract can't call another.
- Don't show "ECRecover", "SHA256 precompile", "RIPEMD160", "Identity"
or even "Call precompile" every time a precompile is called. These are
very well tested now.
- Don't show "executeOpcodes error" whenever a contract returns an error.
(This is changed to `trace` too, it's a normal event that is well tested.)
Signed-off-by: Jamie Lokier <jamie@shareable.org>
This preparation is needed for subsequent
EIPs included in London.
- Add London to Fork enum
- Block number to fork
- Parsing London fork in chain config
- Prepare gas costs table for London
- Prepare EVM opcode dispatcher for London
- Block rewards for London
- Prepare hive script for London
overview:
can be verified by running "make check_vm2 X=0" in the nimbus directory
(be patient when running it.) the X=0 flag is necessary if there is a
native NIM compiler which may bail out at some vendor imports.
details:
when compiling state_transaction.nim, the nim flag vm2_enabled must
be set in order to avoid implicit import of native VM definitions.
why:
kludge not needed anymore for oph_handlers.nim sub-sources and sources
that rely on oph_handlers.nim (but not state_transactions.nim which
relies on computation.nim.)
also:
re-integrated stack_defs.nim back into stack.nim
why:
the v2 prefix of the file name was used as a visual aid when
comparing vm2 against vm sources
why:
the v2 prefix of the file name was used as a visual aid when
comparing vm2 against vm sources
details:
all renamed v2*.nim sources compile locally with the -d:kludge:1 flag
set or without (some work with either)
only sources not renamed yet: v2state_transactions.nim
why:
using function stubs made it possible to check the syntax of an op
handler source file by compiling this very file. this was previously
impossible due cyclic import/include mechanism.
details:
only oph_call.nim, oph_create.nim and subsequently op_handlers.nim
still need the -d:kludge:1 flag for syntax check compiling. this flag
also works with interpreter_dispatch.nim which imports op_handlers.nim.
why:
step towards breaking circular dependency
details:
some functions from v2computation.nim have been extracted into
compu_helper.nim which does not explicitly back-import
v2computation.nim. all non recursive op handlers now import this source
file rather than v2computation.nim.
recursive call/create op handler still need to import v2computation.nim.
the executeOpcodes() function from interpreter_dispatch.nim has been
moved to v2computation.nim which allows for <import> rather than
<include> the interpreter_dispatch.nim source.
why:
this allows for passing back information which can eventually be
used for reducing use of exceptions
caveat:
call/create currently needs to un-capture the call-by-reference
(wrapper) argument using the Computation reference inside
why:
the previous approach was replacing the function-lets in
opcode_impl.nim by the particulate table handlers. the test
functions will verify the the handler functions are sort of
correct but not the assignments in the fork tables.
the handler names of old and new for tables are checked here.
caveat:
verifying tables currently takes a while at compile time.
details:
the op handler table is accessible via op_handlers.nim module
op handler function implementations are found in the op_handlers/
sub-directory
kludge:
for development and pre-testing, any new module can be individually
compiled setting the kludge flag using -d:kludge:1. this causes some
proc/func replacements in turn allowing for omitting imports that would
otherwise cause a circular dependency. otherwise individual compilation
would fail.
in order to prove the overall correctness of the code, the
op_handlers.nim is imported by opcodes_impl.nim when compiling all,
nimbus or test.
jangko
Jamie Lokier
Jordan Hrycaj