The PR makes use of the stacktrie, which is is more lenient on resource consumption, than the regular trie, in cases where we only need it for DeriveSha

This PR implements the following modifications

- Don't shortcut check if block is present, thus avoid disk lookup
- Don't check hash ancestry in early-check (it's still done in parallel checker)
- Don't check time.Now for every single header

Charts and background info can be found here: https://github.com/holiman/headerimport/blob/main/README.md
With these changes, writing 1M headers goes down to from 80s to 62s.

It seems that the 2 second timeout is not enough for Travis CI:

   --- FAIL: TestTestMode (2.00s)
       ethash_test.go:53: sealing result timeout

This PR adds re-written difficulty calculators, which are based on uint256. It also adds a fuzzer + oss-fuzz integration for the new fuzzer. It does differential fuzzing between the new and old calculators.

Note: this PR does not actually enable the new calculators.

* consensus/ethash: only use *reflect.SliceHeader, not reflect.SliceHeader. See comment here: https://github.com/golang/go/issues/40397\#issuecomment-663748689



* consensus/ethash: pr feedback from @mdempsky, makes a copy of dest such that is not mutated

* consensus/ethash: remove noop assign

* consensus/ethash: apply same fix to another location

Co-authored-by: Péter Szilágyi <peterke@gmail.com>
Co-authored-by: Martin Holst Swende <martin@swende.se>

* Bit boundary fix for the DAG generation routine

* Fix unnecessary conversion warnings

Co-authored-by: Sergey Pavlov <spavlov@gmail.com>

This reduces complexity of some lengthy functions in worker.go,
making the code easier to read.

* cmd, consensus, eth, les: implement light fetcher

* les: address comment

* les: address comment

* les: address comments

* les: check td after delivery

* les: add linearExpiredValue for error counter

* les: fix import

* les: fix dead lock

* les: order announces by td

* les: encapsulate invalid counter

* les: address comment

* les: add more checks during the delivery

* les: fix log

* eth, les: fix lint

* eth/fetcher: address comment

This change introduces garbage collection for the light client. Historical
chain data is deleted periodically. If you want to disable the GC, use
the --light.nopruning flag.

Co-authored-by: linjing <linjingjing@baidu.com>

* cmd, core, eth: init tx lookup in background

* core/rawdb: tiny log fixes to make it clearer what's happening

* core, eth: fix rebase errors

* core/rawdb: make reindexing less generic, but more optimal

* rlp: implement rlp list iterator

* core/rawdb: new implementation of tx indexing/unindex using generic tx iterator and hashing rlp-data

* core/rawdb, cmd/utils: fix review concerns

* cmd/utils: fix merge issue

* core/rawdb: add some log formatting polishes

Co-authored-by: rjl493456442 <garyrong0905@gmail.com>
Co-authored-by: Péter Szilágyi <peterke@gmail.com>

* cmd, consensus: add option to disable mmap for DAG caches/datasets

* consensus: add benchmarks for mmap with/with lock

* consensus/ethash, params: implement eip-2384: bump difficulty bomb

* params: EIP 2384 compat checks

* consensus, params: add Muir Glacier block number (mainnet,ropsten) + official name

* core/forkid: forkid tests for muir glacier

* params/config: address review concerns

* params, core/forkid: review nitpicks

* cmd/geth,eth,les: add override option for muir glacier

* params: nit fix

The original idea behind this change was to remove a use of the
deprecated CancelRequest method. Simply removing it would've been an
option, but I couldn't resist and did a bit of a refactoring instead.

All remote sealing code was contained in a single giant function. Remote
sealing is now extracted into its own object, remoteSealer.

Also unexport the status struct.

This PR introduces clique_status which gives info about the health of
the clique network.

It's currently a bit PITA to find out how a clique network is
performing, and it can easily happen that sealers drop off -- and
everything is 'fine' until one more signer drops off, and the network
suddenly halts.

The new method provides the following stats:

- Which signers are currently active, and have signed blocks in the last
  N (set to 64) blocks?
- How many blocks has each signer signed?
- What is the difficulty in the last N blocks, compared to the
  theoretical maximum?

* travis: Enable ARM support

* Include fixes from 20039

* Add a trace to debug the invalid lookup issue

* Try increasing the timeout to see if the arm test passes

* Investigate the resolver issue

* Increase arm64 timeout for clique test

* increase timeout in tests for arm64

* Only test the failing tests

* Review feedback: don't export epsilon

* Remove investigation tricks+include fjl's feeback

* Revert the retry ahead of using the mock resolver

* Fix rebase errors

Original change by @jpeletier 

* core: fix import errors on clique crashes + empty blocks

* cosensus/clique, core: add test for the mirrored state issue

* core: address todo question wrt log count

* core: raise a louder warning for non-clique known blocks

* consensus,core,miner: avoid overhead of creating a new block

* consensus: nitpick dot

* consensus: fix some comment formatting nits

* all: simplify timestamps to uint64

* tests: update definitions

* clef, faucet, mobile: leftover uint64 fixups

* ethash: fix tests

* graphql: update schema for timestamp

* ethash: remove unused variable

* Named functions and defined a basic EIP191 content type list

* Written basic content type functions

* Added ecRecover method in the clef api

* Updated the extapi changelog and addded indications in the README

* Changed the version of the external API

* Added tests for 0x45

* Implementing UnmarshalJSON() for TypedData

* Working on TypedData

* Solved the auditlog issue

* Changed method to signTypedData

* Changed mimes and implemented the 'encodeType' function for EIP-712

* Polished docstrings, ran goimports and swapped fmt.Errorf with errors.New where possible

* Drafted recursive encodeData

* Ran goimports and gofmt

* Drafted first version of EIP-712, including tests

* Temporarily switched to using common.Address in tests

* Drafted text/validator and and rewritten []byte as hexutil.Bytes

* Solved stringified address encoding issue

* Changed the property type required by signData from bytes to interface{}

* Fixed bugs in 'data/typed' signs

* Brought legal warning back after temporarily disabling it for development

* Added example RPC calls for account_signData and account_signTypedData

* Named functions and defined a basic EIP191 content type list

* Written basic content type functions

* Added ecRecover method in the clef api

* Updated the extapi changelog and addded indications in the README

* Added tests for 0x45

* Implementing UnmarshalJSON() for TypedData

* Working on TypedData

* Solved the auditlog issue

* Changed method to signTypedData

* Changed mimes and implemented the 'encodeType' function for EIP-712

* Polished docstrings, ran goimports and swapped fmt.Errorf with errors.New where possible

* Drafted recursive encodeData

* Ran goimports and gofmt

* Drafted first version of EIP-712, including tests

* Temporarily switched to using common.Address in tests

* Drafted text/validator and and rewritten []byte as hexutil.Bytes

* Solved stringified address encoding issue

* Changed the property type required by signData from bytes to interface{}

* Fixed bugs in 'data/typed' signs

* Brought legal warning back after temporarily disabling it for development

* Added example RPC calls for account_signData and account_signTypedData

* Polished and fixed PR

* Polished and fixed PR

* Solved malformed data panics and also wrote tests

* Solved malformed data panics and also wrote tests

* Added alphabetical sorting to type dependencies

* Added alphabetical sorting to type dependencies

* Added pretty print to data/typed UI

* Added pretty print to data/typed UI

* signer: more tests for typed data

* signer: more tests for typed data

* Fixed TestMalformedData4 errors and renamed IsValid to Validate

* Fixed TestMalformedData4 errors and renamed IsValid to Validate

* Fixed more new failing tests and deanonymised some functions

* Fixed more new failing tests and deanonymised some functions

* Added types to EIP712 output in cliui

* Added types to EIP712 output in cliui

* Fixed regexp issues

* Fixed regexp issues

* Added pseudo-failing test

* Added pseudo-failing test

* Fixed false positive test

* Fixed false positive test

* Added PrettyPrint method

* Added PrettyPrint method

* signer: refactor formatting and UI

* signer: make ui use new message format for signing

* Fixed breaking changes

* Fixed rules_test failing test

* Added extra regexp for reference types

* signer: more hard types

* Fixed failing test, formatted files

* signer: use golang/x keccak

* Fixed goimports error

* clef, signer: address some review concerns

* Implemented latest recommendations

* Fixed comments and uintint256 issue

* accounts, signer: fix mimetypes, add interface to sign data with passphrase

* signer, accounts: remove duplicated code, pass hash preimages to signing

* signer: prevent panic in type assertions, make cliui print rawdata as quotable-safe

* signer: linter fixes, remove deprecated crypto dependency

* accounts: fix goimport

* accounts, eth, clique: implement external backend + move sighash calc to backend

* signer: implement account_Version on external API

* accounts/external: enable ipc, add copyright

* accounts, internal, signer: formatting

* node: go fmt

* flags: disallow --dev in combo with --externalsigner

* accounts: remove clique-specific signing method, replace with more generic

* accounts, consensus: formatting + fix error in tests

* signer/core: remove (test-) import cycle

* clique: remove unused import

* accounts: remove CliqueHash and avoid dependency on package crypto

* consensus/clique: unduplicate header encoding