core: minor evm polishes and optimizations

core/evm.go

@@ -60,13 +60,26 @@ func NewEVMContext(msg Message, header *types.Header, chain ChainContext, author
 
 // GetHashFn returns a GetHashFunc which retrieves header hashes by number
 func GetHashFn(ref *types.Header, chain ChainContext) func(n uint64) common.Hash {
+	var cache map[uint64]common.Hash
+
 	return func(n uint64) common.Hash {
+		// If there's no hash cache yet, make one
+		if cache == nil {
+			cache = map[uint64]common.Hash{
+				ref.Number.Uint64() - 1: ref.ParentHash,
+			}
+		}
+		// Try to fulfill the request from the cache
+		if hash, ok := cache[n]; ok {
+			return hash
+		}
+		// Not cached, iterate the blocks and cache the hashes
 		for header := chain.GetHeader(ref.ParentHash, ref.Number.Uint64()-1); header != nil; header = chain.GetHeader(header.ParentHash, header.Number.Uint64()-1) {
-			if header.Number.Uint64() == n {
-				return header.Hash()
+			cache[header.Number.Uint64()-1] = header.ParentHash
+			if n == header.Number.Uint64()-1 {
+				return header.ParentHash
 			}
 		}
-
 		return common.Hash{}
 	}
 }

core/headerchain.go

@@ -23,6 +23,7 @@ import (
 	"math"
 	"math/big"
 	mrand "math/rand"
+	"sync/atomic"
 	"time"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -32,7 +33,6 @@ import (
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/params"
 	"github.com/hashicorp/golang-lru"
-	"sync/atomic"
 )
 
 const (

core/vm/intpool.go

@@ -32,24 +32,36 @@ func newIntPool() *intPool {
 	return &intPool{pool: newstack()}
 }
 
+// get retrieves a big int from the pool, allocating one if the pool is empty.
+// Note, the returned int's value is arbitrary and will not be zeroed!
 func (p *intPool) get() *big.Int {
 	if p.pool.len() > 0 {
 		return p.pool.pop()
 	}
 	return new(big.Int)
 }
+
+// getZero retrieves a big int from the pool, setting it to zero or allocating
+// a new one if the pool is empty.
+func (p *intPool) getZero() *big.Int {
+	if p.pool.len() > 0 {
+		return p.pool.pop().SetUint64(0)
+	}
+	return new(big.Int)
+}
+
+// put returns an allocated big int to the pool to be later reused by get calls.
+// Note, the values as saved as is; neither put nor get zeroes the ints out!
 func (p *intPool) put(is ...*big.Int) {
 	if len(p.pool.data) > poolLimit {
 		return
 	}
-
 	for _, i := range is {
 		// verifyPool is a build flag. Pool verification makes sure the integrity
 		// of the integer pool by comparing values to a default value.
 		if verifyPool {
 			i.Set(checkVal)
 		}
-
 		p.pool.push(i)
 	}
 }