From a1d7279f89986faa0b231cb3d08ca34b27bd1c2a Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Pawe=C5=82=20Bylica?= Date: Thu, 16 Dec 2021 09:44:16 +0100 Subject: [PATCH 1/2] core/vm: reverse bit order in bytes of code bitmap This bit order is more natural for bit manipulation operations and we can eliminate some small number of CPU instructions. --- core/vm/analysis.go | 28 +++++++++++++--------------- core/vm/analysis_test.go | 40 ++++++++++++++++++++++------------------ 2 files changed, 35 insertions(+), 33 deletions(-) diff --git a/core/vm/analysis.go b/core/vm/analysis.go index 449cded2a896..d72105d4e6a9 100644 --- a/core/vm/analysis.go +++ b/core/vm/analysis.go @@ -17,12 +17,12 @@ package vm const ( - set2BitsMask = uint16(0b1100_0000_0000_0000) - set3BitsMask = uint16(0b1110_0000_0000_0000) - set4BitsMask = uint16(0b1111_0000_0000_0000) - set5BitsMask = uint16(0b1111_1000_0000_0000) - set6BitsMask = uint16(0b1111_1100_0000_0000) - set7BitsMask = uint16(0b1111_1110_0000_0000) + set2BitsMask = uint16(0b11) + set3BitsMask = uint16(0b111) + set4BitsMask = uint16(0b1111) + set5BitsMask = uint16(0b1_1111) + set6BitsMask = uint16(0b11_1111) + set7BitsMask = uint16(0b111_1111) ) // bitvec is a bit vector which maps bytes in a program. @@ -31,7 +31,7 @@ const ( type bitvec []byte var lookup = [8]byte{ - 0x80, 0x40, 0x20, 0x10, 0x8, 0x4, 0x2, 0x1, + 0x1, 0x2, 0x4, 0x8, 0x10, 0x20, 0x40, 0x80, } func (bits bitvec) set1(pos uint64) { @@ -39,23 +39,21 @@ func (bits bitvec) set1(pos uint64) { } func (bits bitvec) setN(flag uint16, pos uint64) { - a := flag >> (pos % 8) - bits[pos/8] |= byte(a >> 8) - if b := byte(a); b != 0 { - // If the bit-setting affects the neighbouring byte, we can assign - no need to OR it, - // since it's the first write to that byte + a := flag << (pos % 8) + bits[pos/8] |= byte(a) + if b := byte(a >> 8); b != 0 { bits[pos/8+1] = b } } func (bits bitvec) set8(pos uint64) { - a := byte(0xFF >> (pos % 8)) + a := byte(0xFF << (pos % 8)) bits[pos/8] |= a bits[pos/8+1] = ^a } func (bits bitvec) set16(pos uint64) { - a := byte(0xFF >> (pos % 8)) + a := byte(0xFF << (pos % 8)) bits[pos/8] |= a bits[pos/8+1] = 0xFF bits[pos/8+2] = ^a @@ -63,7 +61,7 @@ func (bits bitvec) set16(pos uint64) { // codeSegment checks if the position is in a code segment. func (bits *bitvec) codeSegment(pos uint64) bool { - return ((*bits)[pos/8] & (0x80 >> (pos % 8))) == 0 + return (((*bits)[pos/8] >> (pos % 8)) & 1) == 0 } // codeBitmap collects data locations in code. diff --git a/core/vm/analysis_test.go b/core/vm/analysis_test.go index d7f21e04aa76..398861f8ae7d 100644 --- a/core/vm/analysis_test.go +++ b/core/vm/analysis_test.go @@ -17,6 +17,7 @@ package vm import ( + "math/bits" "testing" "github.com/ethereum/go-ethereum/crypto" @@ -28,24 +29,27 @@ func TestJumpDestAnalysis(t *testing.T) { exp byte which int }{ - {[]byte{byte(PUSH1), 0x01, 0x01, 0x01}, 0x40, 0}, - {[]byte{byte(PUSH1), byte(PUSH1), byte(PUSH1), byte(PUSH1)}, 0x50, 0}, - {[]byte{byte(PUSH8), byte(PUSH8), byte(PUSH8), byte(PUSH8), byte(PUSH8), byte(PUSH8), byte(PUSH8), byte(PUSH8), 0x01, 0x01, 0x01}, 0x7F, 0}, - {[]byte{byte(PUSH8), 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01}, 0x80, 1}, - {[]byte{0x01, 0x01, 0x01, 0x01, 0x01, byte(PUSH2), byte(PUSH2), byte(PUSH2), 0x01, 0x01, 0x01}, 0x03, 0}, - {[]byte{0x01, 0x01, 0x01, 0x01, 0x01, byte(PUSH2), 0x01, 0x01, 0x01, 0x01, 0x01}, 0x00, 1}, - {[]byte{byte(PUSH3), 0x01, 0x01, 0x01, byte(PUSH1), 0x01, 0x01, 0x01, 0x01, 0x01, 0x01}, 0x74, 0}, - {[]byte{byte(PUSH3), 0x01, 0x01, 0x01, byte(PUSH1), 0x01, 0x01, 0x01, 0x01, 0x01, 0x01}, 0x00, 1}, - {[]byte{0x01, byte(PUSH8), 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01}, 0x3F, 0}, - {[]byte{0x01, byte(PUSH8), 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01}, 0xC0, 1}, - {[]byte{byte(PUSH16), 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01}, 0x7F, 0}, - {[]byte{byte(PUSH16), 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01}, 0xFF, 1}, - {[]byte{byte(PUSH16), 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01}, 0x80, 2}, - {[]byte{byte(PUSH8), 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, byte(PUSH1), 0x01}, 0x7f, 0}, - {[]byte{byte(PUSH8), 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, byte(PUSH1), 0x01}, 0xA0, 1}, - {[]byte{byte(PUSH32)}, 0x7F, 0}, - {[]byte{byte(PUSH32)}, 0xFF, 1}, - {[]byte{byte(PUSH32)}, 0xFF, 2}, + {[]byte{byte(PUSH1), 0x01, 0x01, 0x01}, 0b0000_0010, 0}, + {[]byte{byte(PUSH1), byte(PUSH1), byte(PUSH1), byte(PUSH1)}, 0b0000_1010, 0}, + {[]byte{0x00, byte(PUSH1), 0x00, byte(PUSH1), 0x00, byte(PUSH1), 0x00, byte(PUSH1)}, 0b0101_0100, 0}, + {[]byte{byte(PUSH8), byte(PUSH8), byte(PUSH8), byte(PUSH8), byte(PUSH8), byte(PUSH8), byte(PUSH8), byte(PUSH8), 0x01, 0x01, 0x01}, bits.Reverse8(0x7F), 0}, + {[]byte{byte(PUSH8), 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01}, 0b0000_0001, 1}, + {[]byte{0x01, 0x01, 0x01, 0x01, 0x01, byte(PUSH2), byte(PUSH2), byte(PUSH2), 0x01, 0x01, 0x01}, 0b1100_0000, 0}, + {[]byte{0x01, 0x01, 0x01, 0x01, 0x01, byte(PUSH2), 0x01, 0x01, 0x01, 0x01, 0x01}, 0b0000_0000, 1}, + {[]byte{byte(PUSH3), 0x01, 0x01, 0x01, byte(PUSH1), 0x01, 0x01, 0x01, 0x01, 0x01, 0x01}, 0b0010_1110, 0}, + {[]byte{byte(PUSH3), 0x01, 0x01, 0x01, byte(PUSH1), 0x01, 0x01, 0x01, 0x01, 0x01, 0x01}, 0b0000_0000, 1}, + {[]byte{0x01, byte(PUSH8), 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01}, 0b1111_1100, 0}, + {[]byte{0x01, byte(PUSH8), 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01}, 0b0000_0011, 1}, + {[]byte{byte(PUSH16), 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01}, 0b1111_1110, 0}, + {[]byte{byte(PUSH16), 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01}, 0b1111_1111, 1}, + {[]byte{byte(PUSH16), 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01}, 0b0000_0001, 2}, + {[]byte{byte(PUSH8), 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, byte(PUSH1), 0x01}, 0b1111_1110, 0}, + {[]byte{byte(PUSH8), 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, byte(PUSH1), 0x01}, 0b0000_0101, 1}, + {[]byte{byte(PUSH32)}, 0b1111_1110, 0}, + {[]byte{byte(PUSH32)}, 0b1111_1111, 1}, + {[]byte{byte(PUSH32)}, 0b1111_1111, 2}, + {[]byte{byte(PUSH32)}, 0b1111_1111, 3}, + {[]byte{byte(PUSH32)}, 0b0000_0001, 4}, } for i, test := range tests { ret := codeBitmap(test.code) From a864a7e297a1961fc1dcaac9b53adcac2a713f76 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Pawe=C5=82=20Bylica?= Date: Thu, 16 Dec 2021 10:07:43 +0100 Subject: [PATCH 2/2] core/vm: drop lookup table --- core/vm/analysis.go | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/core/vm/analysis.go b/core/vm/analysis.go index d72105d4e6a9..3733bab6a7c0 100644 --- a/core/vm/analysis.go +++ b/core/vm/analysis.go @@ -30,12 +30,8 @@ const ( // it's data (i.e. argument of PUSHxx). type bitvec []byte -var lookup = [8]byte{ - 0x1, 0x2, 0x4, 0x8, 0x10, 0x20, 0x40, 0x80, -} - func (bits bitvec) set1(pos uint64) { - bits[pos/8] |= lookup[pos%8] + bits[pos/8] |= 1 << (pos % 8) } func (bits bitvec) setN(flag uint16, pos uint64) {