The EVM stack is a hot spot in EVM execution and we end up paying a nim
seq tax in several ways, adding up to ~5% of execution time:
* on initial allocation, all bytes get zeroed - this means we have to
choose between allocating a full stack or just a partial one and then
growing it
* pushing and popping introduce additional zeroing
* reallocations on growth copy + zero - expensive again!
* redundant range checking on every operation reducing inlining etc
Here a custom stack using C memory is instroduced:
* no zeroing on allocation
* full stack allocated on EVM startup -> no reallocation during
execution
* fast push/pop - no zeroing again
* 32-byte alignment - this makes it easier for the compiler to use
vector instructions
* no stack allocated for precompiles (these never use it anyway)
Of course, this change also means we have to manage memory manually -
for the EVM, this turns out to be not too bad because we already manage
database transactions the same way (they have to be freed "manually") so
we can simply latch on to this mechanism.
While we're at it, this PR also skips database lookup for known
precompiles by resolving such addresses earlier.
This is a minimal set of changes to make things work with the new types
in nim-eth - this is the minimal PR that merely resolves
incompatibilities while the full change set would include more cleanup
and migration.
* Remove exception from evm memory
* Remove exception from gas meter
* Remove exception from stack
* Remove exception from precompiles
* Remove exception from gas_costs
* Remove exception from op handlers
* Remove exception from op dispatcher
* Remove exception from call_evm
* Remove exception from EVM
* Fix tools and tests
* Remove exception from EVMC
* fix evmc
* Fix evmc
* Remove remnants of async evm stuff
* Remove superflous error handling
* Proc to func
* Fix errors detected by CI
* Fix EVM op call stack usage
* REmove exception handling from getVmState
* Better error message instead of just doAssert
* Remove unused validation
* Remove superflous catchRaise
* Use results.expect instead of unsafeValue
* Recreating some of the speculative-execution code.
Not really using it yet. Also there's some new inefficiency in
memory.nim, but it's fixable - just haven't gotten around to it yet.
The big thing introduced here is the idea of "cells" for stack,
memory, and storage values. A cell is basically just a Future (though
there's also the option of making it an Identity - just a simple
distinct wrapper around a value - if you want to turn off the
asynchrony).
* Bumped nim-eth.
* Cleaned up a few comments.
* Bumped nim-secp256k1.
* Oops.
* Fixing a few compiler errors that show up with EVMC enabled.
* Silence some compiler gossip -- part 6, evm
details:
Adding some missing exception annotation
* Update evmc cases
why:
were previously missing
* Increase Windows stack needed to run EVMC unit tests
why:
After annotating functions to trace exceptions some unit tests started
to fail on Windows without clear error report.
EVMC works recursively and now there seems to be a stack problem
reported by the nim compiler. Increasing the NIM stack ass sugessted by
NIM (using -d:nimCallDepthLimit=###) had some effect but no clear
solution.
Note that this patch set unrolls some NIM compiler settings
* Silence some compiler gossip -- part 5, common
details:
Mostly removing redundant imports and `Defect` tracer after switch
to nim 1.6
* Silence some compiler gossip -- part 6, db, rpc, utils
details:
Mostly removing redundant imports and `Defect` tracer after switch
to nim 1.6
* Silence some compiler gossip -- part 7, randomly collected source files
details:
Mostly removing redundant imports and `Defect` tracer after switch
to nim 1.6
* Silence some compiler gossip -- part 8, assorted tests
details:
Mostly removing redundant imports and `Defect` tracer after switch
to nim 1.6
* Clique update
why:
More impossible exceptions (undoes temporary fix from previous PR)
Jacek Sieka
andri lim
Adam Spitz
Jordan Hrycaj