The update for London (EIP-1559) in 1cdb30df ("bump nim-emvc with evmc revision
8.0.0 to 9.0.0") really bumped EVMC ABI version from 7.5 up to 9.
In other words, it skipped Berlin, going direct from Istanbul to London.
That was accompanied by EVMC changes in 05e9b891 ("EIP-3198: add baseFee op
code in nim-evm"), which added the API changes needed for London.
But the missing Berlin functions weren't added in the move to London.
As a result, our EVMC host became incompatible with Berlin, London, and really
all revisions of the ABI, and if a third party EVM was loaded, it crashed.
This commit adds the missing Berlin host support, and makes our ABI
binary-compatible with real EVMC again.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
This changes fixes a bug in `CREATE2` ops when used with EVMC.
Because it changes the salt type, it affects non-EVMC code as well.
The salt was passed through EVMC with the wrong byte order, although this went
unnoticed as the Nimbus host flipped the byte order before using it.
This was found when running Nimbus with third-party EVM,
["evmone"](https://github.com/ethereum/evmone).
There are different ways to remedy this.
If treated as a number, Nimbus EVM would byte-flip the value when calling EVMC,
then Nimbus host would flip the received value. Finally, it would be flipped a
third time when generating the address in `generateSafeAddress`. The first two
flips can be eliminated by negotiation (like other numbers), but there would
always be one flip.
As a bit pattern, Nimbus EVM would flip the same way it does when dealing with
hashes on the stack (e.g. with `getBlockHash`). Nimbus host wouldn't flip at
all - and when using third-party EVMs there would be no flips in Nimbus.
Because this value is not for arithmetic, any bit pattern is valid, and there
shouldn't be any flips when using a third-party EVM, the bit-pattern
interpretation is favoured. The only flip is done in Nimbus EVM (and might be
eliminated in an optimised version).
As suggested, we'll define a new "opaque 256 bits" type to hold this value.
(Similar to `Hash256`, but the salt isn't necessarily a hash.)
Signed-off-by: Jamie Lokier <jamie@shareable.org>
Previously max gas refunded was defined as gas_used div 2.
Here we name the constant 2 as MAX_REFUND_QUOTIENT and
change its value to 5.
The new equation will be: gas_used div MAX_REFUND_QUOTIENT
Proper nested call functionality is being skipped in this iteration of new EVMC
host code to keep it simpler, to allow testing and architecture to be built
around the less complicated non-nested cases first.
Instead, nested calls use the old `Computation` path, and bypass any
third-party EVM that may be loaded. The results are the same, and mixing
different EVMs in this way is actually permitted in the EVMC specification.
This approach also means third-party EVMs we test don't need to support
precompiles and we don't need to specially handle those cases.
(E.g. "evmone" doesn't support precompiles, just EVM1 opcodes).
(These before/after scope actions are approximately copy-pasted from
`nimbus/vm/evmc_host.nim`, making their detailed behaviour "obviously correct".
Of course they are subject to tests as well. The small stack property of
a3c8a5c3 "EVMC: Small stacks when using EVMC, closes#575 (segfaults)" is
carefully retained.)
Signed-off-by: Jamie Lokier <jamie@shareable.org>
Make the host service `setStorage` calculate the gas refund itself, instead of
depending on EVM internals.
In EVMC, host `setStorage` is responsible for adding the gas refund using the
rules of EIP-1283 (Constantinople), EIP-2200 (Istanbul) or EIP-2929 (Berlin).
It is not obvious that the host must do it from EVMC documentation, but it's
how it has to be. Note, this is very different from the gas _cost_, which the
host does not calculate.
Gas refund doesn't affect computation. It is applied after the whole
transaction is complete, so it can be tracked on the host or EVM side. But
`setStorage` doesn't return enough information for the EVM to calculate the
refund, so the host must do it when `setStorage` is used.
For now, this continues using Nimbus `Computation` just to hold the gas refund,
to fit around existing structures and get new EVMC working. But the host can't
keep using `Computation`, so gas refund will be moved out of it in due course.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
When processing log operations on the EVMC host side, it causes incorrect
`rootHash` results in some tests. This patch fixes the results.
The cause of these results is known: `Computation` is still doing parts of
contract scope entry/exit which need to be moved to the host. For now, as a
temporary workaround, update logs in `Computation` as it did before.
This makes test pass when using Nimbus EVM. (It breaks third-party EVMs when
`LOG*` ops are used, although most other tests pass.)
We can't keep this as it prevents complete host/EVM separation, but it's useful
in the current code, and it's fine to develop other functionality on top.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
When processing self destructs on the EVMC host side, it causes incorrect
`rootHash` results in some tests. This patch fixes the results.
The cause of these results is known: `Computation` is still doing parts of
contract scope entry/exit which need to be moved to the host. For now, as a
temporary workaround, update self destructs in `Computation` as it did before.
This makes test pass when using Nimbus EVM. (It breaks third-party EVMs when
`SELFDESTRUCT` ops are used, although most other tests pass.)
We can't keep this as it prevents complete host/EVM separation, but it's useful
in the current code, and it's fine to develop other functionality on top.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
In the unusual case where log data is zero-length, `data[0].addr` is invalid
and Nim thoughtfully raises `IndexOutOfBounds`, a `Defect` so it's not even
in `CatchableError`.
This is done in the EVMC host services to handle `LOG*` ops, and it made one
of the EVM tests silently fail with no error message. The fix is obvious.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
Show calls from the host into the EVM. Shows the call, `evmc_message` fields,
and `evmc_result` fields when the call returns.
(When `show_tx_calls` is manually set to true.)
Signed-off-by: Jamie Lokier <jamie@shareable.org>
When `show_tx_calls` is manually set to true, show all the calls from the EVM
to the host, including name, arguments and results.
For example this shows each call to `setStorage`, the key, value and storage
result. This output allows the externally-visible activity of an EVM to be
seen, and it's been useful for guessing what went wrong when a test fails.
In theory, if two EVMs show the same activity in this log, they should have the
same effect on account states, gas, etc. and the same final `roothash`
(which is the only value some tests check).
ps. Ideally we'd use `{.push show.}`...`{.pop.}`, just like with `inline`.
But we can't: https://github.com/nim-lang/Nim/issues/12867
Signed-off-by: Jamie Lokier <jamie@shareable.org>
New pragma `{.show.}` on a proc definition turns on tracing for that proc.
Every call to it shows the name, arguments and results, if `show_tx_calls` is
manually set to true. This is to trace calls from EVM to host.
This started as a template which took a block expression, but the closure it
used led to illegal capture errors. It was easier to write a macro.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
1. Send all EVM executions through the EVMC `execute` function.
It leads to the same place in the end as calling `Computation` before, but
`execute` is the API function used by all EVMC implementations, and it is
very explicit what data is passed back and forth.
2. As a consequence this starts using the new `host_services` code from EVM, so
this is a significant change to the paths used for account state processing.
3. Because we will have to remove the `newComputation` call on the host side,
anticipating that the contract code is now saved in `host` instead of being
copied around. As it's saved in `host`, there is no need to pass it
separately to `evmcExecComputation`.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
Even though `evmc_create_nimbus_evm` is called, it fails at link time because
the definition of that function isn't included unless it is pulled in
explicitly.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
This provides the functions a loadable VM must provide for a host to use it.
The main access to a loaded EVM is `evmc_create_nimbus_evm`, and this meant to
be the only exported function the caller starts with.
That provides access to other functions, also defined in this patch, to
configure the EVM and then the key interesting function is `execute`.
`execute` runs a full computation, here using Nimbus EVM `Computation`.
(Note, even though everything is EVMC binary-compatible, there is a small
dependency on `TransactionHost` in `execute` here, which prevents this being
used by a host that is not Nimbus at the moment. It is necessary for some
tests, and will eventually go away.)
Although this provides the VM-side functionality needed by the host, it does
not contain the glue functions for `Computation` to call the host, which are
already part of the Nimbus EVM in `nimbus/vm/evmc_api.nim`.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
1. This provides the necessary type adjustments for host services to be
(optionally) callable via the EVMC binary-compatible interface. This layer
is stashed away in a glue module so the host services continue to use
appropriate Nim types, and are still callable directly.
Inlining is used to ensure there should be no real overhead, including stack
frame size for the `call` function. Note, `import` must be used for
`{.inline.}` to work effectively.
2. This also provides a key call in the other direction, the version of host to
EVM `execute` that is called on the host side.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
This provides "host services", functions provided by the application to an EVM.
They are a key part of EVMC compatibility, but we will switch to using these
with "native" EVM as well.
These are functions like `getStorage`, `setStorage` and `emitLog` for accessing
the account state, because the EVM is not allowed direct access to the database.
This code is adapted from `nimbus/vm/evmc_host.nim` and other places, but there
is more emphasis on being host-side only, no dependency on the EVM or
`Computation` type. It uses `TransactionHost` and types in `host_types`.
These host services have two goals: To be compatible with EVMC, and to be a
good way for the Nimbus EVM to access the data it needs. In our new Nimbus
internal architecture, the EVM will only access the databases and other
application state via these host service functions.
The reason for containing the EVM like this, even "native" EVM, is that having
one good interface to the data makes it a lot easier to change how the database
works, which is on the roadmap.
These functions almost have EVMC signatures, but they are not binary compatible
with EVMC. (Binary compatibility is provided by another module). It would be
fine for Nimbus EVM to call these functions directly when linked directly.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
File `vm_types2` is obsolete. Remove this file and divert all imports to the
common forks list outside the EVM, or in some cases they don't need it anyway.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
The current EVM generates its own new contract addresses, and this is why there
are separate `msg.contractAddress` and `msg.codeAddress` fields in the
computation start message.
In EVMC, account updates are only allowed on the host side, including contract
generation, and the start message has one destination field, `msg.destination`.
The EVM cannot select addresses, only use them. It's a sensible design.
The difference makes the current EVM incompatible with EVMC and its message
format, so this patch corrects the difference. It moves contract address
generation to the host side. This simplifies the EVM and its API a little.
(As an API change, this is incompatible with vm2, so it's guarded under
`evmc_enabled` to allow vm2 to continue to build and run at this time. This is
also why there are fewer deletions than would otherwise be expected.)
Signed-off-by: Jamie Lokier <jamie@shareable.org>
The last caller of `setupComputation` is gone, now that it's been replaced by
the single entry point for all EVM calls, `runComputation`.
With this removal, EVM's `Computation` type should no longer be used anywhere
outside the call module (except in some tests and the EVM itself).
Signed-off-by: Jamie Lokier <jamie@shareable.org>
Simplify transaction validations to use `runComputation`; drop other code.
Getting everything right up to this point to pass all the tests was trickier
than it looks.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
Simplify how JSON fixtures tests are run to use `runComputation`.
Drop other code.
These use the `noTransfer` option, which is similar enough to calling
`c.executeOpcodes()` instead of `c.execComputation()`.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
Add another flag to disable a processing step when a call doesn't come from
a real transaction:
- `noTransfer`: Don't update balances, nonces, code.
This is to support VM fixtures tests which require account balances and nonces
to be unchanged when running the account's code.
These tests call `c.executeOpcodes()`, an internal function of the EVM, instead
of the usual `c.execComputation()`. It goes direct to the bytecode dispatcher,
skipping parts of `Computation` that are normally called.
But we can't keep calling `c.executeOpcodes()` and have a single entry point to
the VM, let alone an EVMC entry point.
`noTransfer` provides similar enough behaviour to calling `c.executeOpcodes()`
that these tests can use the new single entry point like everything else.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
Simplify `estimateGas` to use `runComputation`; drop other code.
The RPC/GraphQL `estimateGas` operation is quite different from the `call`
operation. It is much more like ordinary transaction execution than `call`,
though there are still enough differences that tx validation cannot be used.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
Simplify `call` to use `runComputation`; drop other code.
The RPC/GraphQL `call` operation differs in many ways from regular transaction
calls. The following flags are set, to disable various steps in processing.
All four are true (disabling the corresponding step) for `call`:
- `noIntrinsic`: Don't charge intrinsic gas.
- `noAccessList`: Don't initialise EIP2929 access list.
- `noGasCharge`: Don't charge sender account for gas.
- `noRefund`: Don't apply gas refund/burn rule.
Interestingly, the RPC/GraphQL `estimateGas` operation doesn't behave so
differently from regular transactions. It might be that not all these steps
should be disabled for `call` either. But until we investigate what
RPC/GraphQL clients are expecting, keep the same behaviour as before.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
The following four flags are added, to change various steps in EVM processing
when a call doesn't come from a real transaction:
- `noIntrinsic`: Don't charge intrinsic gas.
- `noAccessList`: Don't initialise EIP2929 access list.
- `noGasCharge`: Don't charge sender account for gas.
- `noRefund`: Don't apply gas refund/burn rule.
This is to support RPC and GraphQL `call` operations, which behave differently
in some ways from regular transaction calls, and to support some test suites.
In EVMC terms, all these alterations can be performed on the host side.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
Calculate extra intrinsic gas for an EIP-2930 transaction with access list.
While we're here, do the rest of the intrinsic gas calculation. Make it clear,
explicit and in one place. (Previous code delegated parts of the calculation
to `transaction.nim` but had to do the rest locally due to mismatched types.)
Signed-off-by: Jamie Lokier <jamie@shareable.org>
New entry point `runComputation`, for all EVM calls.
(Later the intent is `runComputationAsync`.)
As noted in commit 297d789, there are six entry points calling EVM computation,
with different parameters and expecting different behaviours. Parameters were
dealt with in `setupComputation`. Behaviours are unified in `runComputation`,
with options passed via `CallParams`.
This code performs the steps used when validating a transaction. Options for
non-standard behaviour for RPC, GraphQL and tests to be added as required.
This replaces `setupComputation`, `execComputation` and `executeOpcodes`
(other than its own calls). As a result `Computation` and other EVM types are
no longer referenced in the main program, and many imports can be dropped.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
Change fixtures tests to use shared `setupComputation` instead of
their own slightly different variant.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
Change RPC/GraphQL calls to the EVM to use shared `setupComputation`
instead of their own special variant.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
There are currently six entry points to running an EVM computation, all with
slightly different parameters, and expecting slightly different EVM behaviours.
First step in merging them is a common `setupComputation` that replaces all
the different `*...SetupComputation` functions.
This uses the `TransactionHost` type because it's a step towards using that
type for all EVM calls using only EVMC. For now an EVMC message is created
then translated to EVM-internal `Message`. It is done this way to build up
the new interface in stages where all tests pass at each stage.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
`TransactionHost` represents the interface to the EVM from the application once
we've fully transitioned to EVMC. It represents a managed EVM call, and the
"EVMC host" side of the host<->EVM boundary.
This holds transaction state which sits outside the EVM, but a pointer to this
is passed around by the EVM as _opaque_ type `evmc_host_context`.
To the EVM, this offers "host services", which manage account state that the
EVM cannot do, such as balance transfers, call costs, storage, logs, gas
refunds, nested calls and new contract addresses. The EVM has no direct access
to the account state database or network; it's all via "host services".
To the application (host side), this object represents a managed EVM call, with
inputs, a method to run, outputs, hidden transaction state, and later async
scheduling. It is to replace `Computation` on the application side, while
`Computation` will remain but just be for the EVM side.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
Each place in `call_evm` that sets up an EVM call calculates the new contract
address for contract creations. But it's redundant, because `newComputation`
ignores the provided value and does the calculation again.
Remove the unused address calculation.
This is also a step to merging different entry points and EVMC. This change
ends up with the same value in both `msg.contractAddress` and `msg.codeAddress`
for every entry point, and this is good because it matches the EVMC message
structure, where they are replaced by only one value called `msg.destination`
Signed-off-by: Jamie Lokier <jamie@shareable.org>
`c.executeOpcodes` is called by some JSON fixture tests. These tests bypass
some of the setup and return, and because of this call, continuations aren't
processed either. Opcodes that use continuations will behave incorrectly.
The opcodes used in these particular tests don't use continuations currently,
so just add some assertions to verify this remains the case.
This is only used by local tests, and the call to `c.executeOpcodes` will be
replaced by the common entry point (that handles things like this correctly in
all cases) so we don't need to spend more time on this.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
Move the EVM setup and call in precompile tests to `fixtureCallEvm` in
`call_evm`. Extra return values needed for testing are returned specially, and
the convention for reporting gas used is changed to match `asmCallEvm`.
Although the precompile tests used `execPrecompiles` before, `executeOpcodes`
does perfectly well as a substitute, allowing `fixtureCallEvm` to be shared.
_Significantly, this patch also makes `Computation` more or less an internal
type of the EVM now._
Nothing outside the EVM (except `call_evm`) needs access any more to
`Computation`, `execComputation`, `executeOpcodes` or `execPrecompiles`.
Many imports can be trimmed, some files removed, and EVMC is much closer.
(As a bonus, the functions in `call_evm` reveal what capabilities parts of the
program have needed over time, makes certain bugs and inconsistencies clearer,
and suggests how to refactor into a more useful shared entry point.)
Signed-off-by: Jamie Lokier <jamie@shareable.org>
Allow the fork to be specified consistently through an `option[Fork]` instead
of varying inconsistencies depending on which call. When fork is not
specified, the `BaseVMState` code picks the correct fork by default for the
block number and chain.
This change actually deletes code, because a number of functions (RPC etc) had
redundant code to pick the fork, which always resolved to same as default.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
Move the EVM setup and call in fixtures "vm json tests" to new function
`fixtureCallEvm` in `call_evm`. Extra return values needed for testing are
returned specially.
This entry point is different from all other `..CallEvm` type functions,
because it uses `executeOpcodes` instead of `execComputation`, so it doesn't
update the account balance or nonce on entry and exit from the EVM.
The new code is a bit redundant and simplistic intentionally, as the purpose is
to move functionality to `call_evm` with high confidence nothing really
changed. The calls will be jointly refactored afterwards to merge differences.
Signed-off-by: Jamie Lokier <jamie@shareable.org>
Jamie Lokier
jangko