core/vm: polish precompile contract code, add tests and benches

 * Update modexp gas calculation to new version
 * Fix modexp modulo 0 special case to return zero

1 files changed, 91 insertions, 10 deletions

diff --git a/core/vm/contracts_test.go b/core/vm/contracts_test.go
index 2b4070ede..d04957161 100644
--- a/core/vm/contracts_test.go
+++ b/core/vm/contracts_test.go
@@ -1,17 +1,100 @@
 package vm
 
 import (
+	"bytes"
+	"math"
 	"testing"
 
 	"github.com/ethereum/go-ethereum/common"
 )
 
-const input = ""
+// Tests the sample inputs from the ModExp EIP 198.
+func TestPrecompiledModExp(t *testing.T) {
+	bigModExp := &bigModExp{}
 
-func TestPairing(t *testing.T) {
-	pairing := &pairing{}
+	for i, tt := range []struct {
+		input  string
+		gas    uint64
+		output string
+	}{
+		{"00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000002003fffffffffffffffffffffffffffffffffffffffffffffffffffffffefffffc2efffffffffffffffffffffffffffffffffffffffffffffffffffffffefffffc2f", 2611, "0000000000000000000000000000000000000000000000000000000000000001"},
+		{"000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000020fffffffffffffffffffffffffffffffffffffffffffffffffffffffefffffc2efffffffffffffffffffffffffffffffffffffffffffffffffffffffefffffc2f", 2611, "0000000000000000000000000000000000000000000000000000000000000000"},
+		{"00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000020fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffefffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffd", math.MaxUint64, ""},
+		{"00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000002003ffff800000000000000000000000000000000000000000000000000000000000000007", 153, "3b01b01ac41f2d6e917c6d6a221ce793802469026d9ab7578fa2e79e4da6aaab"},
+		{"00000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000002000000000000000000000000000000000000000000000000000000000000002003ffff80", 153, "3b01b01ac41f2d6e917c6d6a221ce793802469026d9ab7578fa2e79e4da6aaab"},
+	} {
+		gas := bigModExp.RequiredGas(common.FromHex(tt.input))
+		if gas != tt.gas {
+			t.Errorf("test %d: required gas mismatch: have %v, want %v", i, gas, tt.gas)
+			continue
+		}
+		if gas == math.MaxUint64 {
+			continue // Out of gas
+		}
+		out, err := bigModExp.Run(common.FromHex(tt.input))
+		if err != nil {
+			t.Errorf("test %d: contract execution failed: %v", i, err)
+			continue
+		}
+		if !bytes.Equal(out, common.FromHex(tt.output)) {
+			t.Errorf("test %d: contract output mismatch: have %x, want %v", i, out, tt.output)
+		}
+	}
+}
+
+// Tests the sample inputs from the elliptic curve addition EIP 213.
+func TestPrecompiledBn256Add(t *testing.T) {
+	bn256Add := &bn256Add{}
+
+	for i, tt := range []struct {
+		input   string
+		failure error
+		output  string
+	}{
+		{"0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000", nil, "00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"},
+		{"", nil, "00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"},
+		{"1111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111", errNotOnCurve, ""},
+	} {
+		out, err := bn256Add.Run(common.FromHex(tt.input))
+		if err != tt.failure {
+			t.Errorf("test %d: contract execution failure mismatch: have %v, want %v", i, err, tt.failure)
+			continue
+		}
+		if !bytes.Equal(out, common.FromHex(tt.output)) {
+			t.Errorf("test %d: contract output mismatch: have %x, want %v", i, out, tt.output)
+		}
+	}
+}
+
+// Tests the sample inputs from the elliptic curve scalar multiplication EIP 213.
+func TestPrecompiledBn256ScalarMul(t *testing.T) {
+	bn256ScalarMul := &bn256ScalarMul{}
+
+	for i, tt := range []struct {
+		input   string
+		failure error
+		output  string
+	}{
+		{"000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000", nil, "00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"},
+		{"", nil, "00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"},
+		{"111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111110f00000000000000000000000000000000000000000000000000000000000000", errNotOnCurve, ""},
+	} {
+		out, err := bn256ScalarMul.Run(common.FromHex(tt.input))
+		if err != tt.failure {
+			t.Errorf("test %d: contract execution failure mismatch: have %v, want %v", i, err, tt.failure)
+			continue
+		}
+		if !bytes.Equal(out, common.FromHex(tt.output)) {
+			t.Errorf("test %d: contract output mismatch: have %x, want %v", i, out, tt.output)
+		}
+	}
+}
 
-	for i, test := range []struct {
+// Tests the sample inputs from the elliptic curve pairing check EIP 197.
+func TestPrecompiledBn256Pairing(t *testing.T) {
+	bn256Pairing := &bn256Pairing{}
+
+	for i, tt := range []struct {
 		input string
 		valid int
 	}{
@@ -22,14 +105,12 @@ func TestPairing(t *testing.T) {
 		{"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", 1},
 		{"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", 0},
 	} {
-		r, err := pairing.Run(common.FromHex(test.input))
+		out, err := bn256Pairing.Run(common.FromHex(tt.input))
 		if err != nil {
-			t.Error(i, ":", err)
+			t.Errorf("test %d: contrac execution failed: %v", i, err)
 		}
-
-		if int(r[31]) != test.valid {
-			t.Error(i, "expected", test.valid, "but was", r[31])
+		if int(out[31]) != tt.valid {
+			t.Errorf("test %d: contract output mismatch: have %v, want %v", i, out[31], tt.valid)
 		}
 	}
-
 }