106 lines
2.9 KiB
Rust
106 lines
2.9 KiB
Rust
// Copyright 2015-2018 Parity Technologies (UK) Ltd.
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// This file is part of Parity.
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// Parity is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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// Parity is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with Parity. If not, see <http://www.gnu.org/licenses/>.
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use std::sync::Arc;
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use hash::KECCAK_EMPTY;
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use heapsize::HeapSizeOf;
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use ethereum_types::H256;
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use parking_lot::Mutex;
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use memory_cache::MemoryLruCache;
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use bit_set::BitSet;
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use super::super::instructions;
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const DEFAULT_CACHE_SIZE: usize = 4 * 1024 * 1024;
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// stub for a HeapSizeOf implementation.
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struct Bits(Arc<BitSet>);
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impl HeapSizeOf for Bits {
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fn heap_size_of_children(&self) -> usize {
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// dealing in bits here
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self.0.capacity() * 8
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}
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}
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/// Global cache for EVM interpreter
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pub struct SharedCache {
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jump_destinations: Mutex<MemoryLruCache<H256, Bits>>,
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}
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impl SharedCache {
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/// Create a jump destinations cache with a maximum size in bytes
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/// to cache.
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pub fn new(max_size: usize) -> Self {
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SharedCache {
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jump_destinations: Mutex::new(MemoryLruCache::new(max_size)),
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}
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}
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/// Get jump destinations bitmap for a contract.
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pub fn jump_destinations(&self, code_hash: &H256, code: &[u8]) -> Arc<BitSet> {
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if code_hash == &KECCAK_EMPTY {
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return Self::find_jump_destinations(code);
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}
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if let Some(d) = self.jump_destinations.lock().get_mut(code_hash) {
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return d.0.clone();
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}
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let d = Self::find_jump_destinations(code);
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self.jump_destinations.lock().insert(code_hash.clone(), Bits(d.clone()));
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d
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}
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fn find_jump_destinations(code: &[u8]) -> Arc<BitSet> {
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let mut jump_dests = BitSet::with_capacity(code.len());
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let mut position = 0;
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while position < code.len() {
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let instruction = code[position];
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if instruction == instructions::JUMPDEST {
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jump_dests.insert(position);
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} else if instructions::is_push(instruction) {
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position += instructions::get_push_bytes(instruction);
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}
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position += 1;
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}
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jump_dests.shrink_to_fit();
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Arc::new(jump_dests)
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}
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}
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impl Default for SharedCache {
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fn default() -> Self {
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SharedCache::new(DEFAULT_CACHE_SIZE)
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}
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}
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#[test]
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fn test_find_jump_destinations() {
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use rustc_hex::FromHex;
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// given
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let code = "7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff5b01600055".from_hex().unwrap();
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// when
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let valid_jump_destinations = SharedCache::find_jump_destinations(&code);
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// then
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assert!(valid_jump_destinations.contains(66));
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}
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