core/vm: instruction tests (#16327)

This PR makes it easy to generate and execute testcases for VM arithmetic operations. By enabling and running the testcase TestWriteExpectedValues, a set of json files are created which contain input and output for each arith operation.
The test TestJsonTestcases executes all of those tests.

While meaningless as is, this PR makes it less risky to make changes (optimizations) to the vm operations, since there will be a larger body of testcases.

core/vm/instructions_test.go

@@ -18,6 +18,9 @@ package vm
 
 import (
 	"bytes"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
 	"math/big"
 	"testing"
 
@@ -26,32 +29,91 @@ import (
 	"github.com/ethereum/go-ethereum/params"
 )
 
-type twoOperandTest struct {
-	x        string
-	y        string
-	expected string
+type TwoOperandTestcase struct {
+	X        string
+	Y        string
+	Expected string
 }
 
-func testTwoOperandOp(t *testing.T, tests []twoOperandTest, opFn func(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error)) {
+type twoOperandParams struct {
+	x string
+	y string
+}
+
+var commonParams []*twoOperandParams
+var twoOpMethods map[string]executionFunc
+
+func init() {
+
+	// Params is a list of common edgecases that should be used for some common tests
+	params := []string{
+		"0000000000000000000000000000000000000000000000000000000000000000", // 0
+		"0000000000000000000000000000000000000000000000000000000000000001", // +1
+		"0000000000000000000000000000000000000000000000000000000000000005", // +5
+		"7ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffe", // + max -1
+		"7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", // + max
+		"8000000000000000000000000000000000000000000000000000000000000000", // - max
+		"8000000000000000000000000000000000000000000000000000000000000001", // - max+1
+		"fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffb", // - 5
+		"ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", // - 1
+	}
+	// Params are combined so each param is used on each 'side'
+	commonParams = make([]*twoOperandParams, len(params)*len(params))
+	for i, x := range params {
+		for j, y := range params {
+			commonParams[i*len(params)+j] = &twoOperandParams{x, y}
+		}
+	}
+	twoOpMethods = map[string]executionFunc{
+		"add":     opAdd,
+		"sub":     opSub,
+		"mul":     opMul,
+		"div":     opDiv,
+		"sdiv":    opSdiv,
+		"mod":     opMod,
+		"smod":    opSmod,
+		"exp":     opExp,
+		"signext": opSignExtend,
+		"lt":      opLt,
+		"gt":      opGt,
+		"slt":     opSlt,
+		"sgt":     opSgt,
+		"eq":      opEq,
+		"and":     opAnd,
+		"or":      opOr,
+		"xor":     opXor,
+		"byte":    opByte,
+		"shl":     opSHL,
+		"shr":     opSHR,
+		"sar":     opSAR,
+	}
+}
+
+func testTwoOperandOp(t *testing.T, tests []TwoOperandTestcase, opFn executionFunc, name string) {
+
 	var (
 		env            = NewEVM(Context{}, nil, params.TestChainConfig, Config{})
 		stack          = newstack()
 		pc             = uint64(0)
-		evmInterpreter = NewEVMInterpreter(env, env.vmConfig)
+		evmInterpreter = env.interpreter.(*EVMInterpreter)
 	)
-
-	env.interpreter = evmInterpreter
+	// Stuff a couple of nonzero bigints into pool, to ensure that ops do not rely on pooled integers to be zero
 	evmInterpreter.intPool = poolOfIntPools.get()
+	evmInterpreter.intPool.put(big.NewInt(-1337))
+	evmInterpreter.intPool.put(big.NewInt(-1337))
+	evmInterpreter.intPool.put(big.NewInt(-1337))
+
 	for i, test := range tests {
-		x := new(big.Int).SetBytes(common.Hex2Bytes(test.x))
-		shift := new(big.Int).SetBytes(common.Hex2Bytes(test.y))
-		expected := new(big.Int).SetBytes(common.Hex2Bytes(test.expected))
+		x := new(big.Int).SetBytes(common.Hex2Bytes(test.X))
+		y := new(big.Int).SetBytes(common.Hex2Bytes(test.Y))
+		expected := new(big.Int).SetBytes(common.Hex2Bytes(test.Expected))
 		stack.push(x)
-		stack.push(shift)
+		stack.push(y)
 		opFn(&pc, evmInterpreter, nil, nil, stack)
 		actual := stack.pop()
+
 		if actual.Cmp(expected) != 0 {
-			t.Errorf("Testcase %d, expected  %v, got %v", i, expected, actual)
+			t.Errorf("Testcase %v %d, %v(%x, %x): expected  %x, got %x", name, i, name, x, y, expected, actual)
 		}
 		// Check pool usage
 		// 1.pool is not allowed to contain anything on the stack
@@ -64,7 +126,7 @@ func testTwoOperandOp(t *testing.T, tests []twoOperandTest, opFn func(pc *uint64
 			for evmInterpreter.intPool.pool.len() > 0 {
 				key := evmInterpreter.intPool.get()
 				if _, exist := poolvals[key]; exist {
-					t.Errorf("Testcase %d, pool contains double-entry", i)
+					t.Errorf("Testcase %v %d, pool contains double-entry", name, i)
 				}
 				poolvals[key] = struct{}{}
 			}
@@ -74,47 +136,22 @@ func testTwoOperandOp(t *testing.T, tests []twoOperandTest, opFn func(pc *uint64
 }
 
 func TestByteOp(t *testing.T) {
-	var (
-		env            = NewEVM(Context{}, nil, params.TestChainConfig, Config{})
-		stack          = newstack()
-		evmInterpreter = NewEVMInterpreter(env, env.vmConfig)
-	)
-
-	env.interpreter = evmInterpreter
-	evmInterpreter.intPool = poolOfIntPools.get()
-	tests := []struct {
-		v        string
-		th       uint64
-		expected *big.Int
-	}{
-		{"ABCDEF0908070605040302010000000000000000000000000000000000000000", 0, big.NewInt(0xAB)},
-		{"ABCDEF0908070605040302010000000000000000000000000000000000000000", 1, big.NewInt(0xCD)},
-		{"00CDEF090807060504030201ffffffffffffffffffffffffffffffffffffffff", 0, big.NewInt(0x00)},
-		{"00CDEF090807060504030201ffffffffffffffffffffffffffffffffffffffff", 1, big.NewInt(0xCD)},
-		{"0000000000000000000000000000000000000000000000000000000000102030", 31, big.NewInt(0x30)},
-		{"0000000000000000000000000000000000000000000000000000000000102030", 30, big.NewInt(0x20)},
-		{"ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", 32, big.NewInt(0x0)},
-		{"ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", 0xFFFFFFFFFFFFFFFF, big.NewInt(0x0)},
-	}
-	pc := uint64(0)
-	for _, test := range tests {
-		val := new(big.Int).SetBytes(common.Hex2Bytes(test.v))
-		th := new(big.Int).SetUint64(test.th)
-		stack.push(val)
-		stack.push(th)
-		opByte(&pc, evmInterpreter, nil, nil, stack)
-		actual := stack.pop()
-		if actual.Cmp(test.expected) != 0 {
-			t.Fatalf("Expected  [%v] %v:th byte to be %v, was %v.", test.v, test.th, test.expected, actual)
-		}
+	tests := []TwoOperandTestcase{
+		{"ABCDEF0908070605040302010000000000000000000000000000000000000000", "00", "AB"},
+		{"ABCDEF0908070605040302010000000000000000000000000000000000000000", "01", "CD"},
+		{"00CDEF090807060504030201ffffffffffffffffffffffffffffffffffffffff", "00", "00"},
+		{"00CDEF090807060504030201ffffffffffffffffffffffffffffffffffffffff", "01", "CD"},
+		{"0000000000000000000000000000000000000000000000000000000000102030", "1F", "30"},
+		{"0000000000000000000000000000000000000000000000000000000000102030", "1E", "20"},
+		{"ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", "20", "00"},
+		{"ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", "FFFFFFFFFFFFFFFF", "00"},
 	}
-	poolOfIntPools.put(evmInterpreter.intPool)
+	testTwoOperandOp(t, tests, opByte, "byte")
 }
 
 func TestSHL(t *testing.T) {
 	// Testcases from https://github.com/ethereum/EIPs/blob/master/EIPS/eip-145.md#shl-shift-left
-	tests := []twoOperandTest{
-		{"0000000000000000000000000000000000000000000000000000000000000001", "00", "0000000000000000000000000000000000000000000000000000000000000001"},
+	tests := []TwoOperandTestcase{
 		{"0000000000000000000000000000000000000000000000000000000000000001", "01", "0000000000000000000000000000000000000000000000000000000000000002"},
 		{"0000000000000000000000000000000000000000000000000000000000000001", "ff", "8000000000000000000000000000000000000000000000000000000000000000"},
 		{"0000000000000000000000000000000000000000000000000000000000000001", "0100", "0000000000000000000000000000000000000000000000000000000000000000"},
@@ -126,12 +163,12 @@ func TestSHL(t *testing.T) {
 		{"0000000000000000000000000000000000000000000000000000000000000000", "01", "0000000000000000000000000000000000000000000000000000000000000000"},
 		{"7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", "01", "fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffe"},
 	}
-	testTwoOperandOp(t, tests, opSHL)
+	testTwoOperandOp(t, tests, opSHL, "shl")
 }
 
 func TestSHR(t *testing.T) {
 	// Testcases from https://github.com/ethereum/EIPs/blob/master/EIPS/eip-145.md#shr-logical-shift-right
-	tests := []twoOperandTest{
+	tests := []TwoOperandTestcase{
 		{"0000000000000000000000000000000000000000000000000000000000000001", "00", "0000000000000000000000000000000000000000000000000000000000000001"},
 		{"0000000000000000000000000000000000000000000000000000000000000001", "01", "0000000000000000000000000000000000000000000000000000000000000000"},
 		{"8000000000000000000000000000000000000000000000000000000000000000", "01", "4000000000000000000000000000000000000000000000000000000000000000"},
@@ -144,12 +181,12 @@ func TestSHR(t *testing.T) {
 		{"ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", "0100", "0000000000000000000000000000000000000000000000000000000000000000"},
 		{"0000000000000000000000000000000000000000000000000000000000000000", "01", "0000000000000000000000000000000000000000000000000000000000000000"},
 	}
-	testTwoOperandOp(t, tests, opSHR)
+	testTwoOperandOp(t, tests, opSHR, "shr")
 }
 
 func TestSAR(t *testing.T) {
 	// Testcases from https://github.com/ethereum/EIPs/blob/master/EIPS/eip-145.md#sar-arithmetic-shift-right
-	tests := []twoOperandTest{
+	tests := []TwoOperandTestcase{
 		{"0000000000000000000000000000000000000000000000000000000000000001", "00", "0000000000000000000000000000000000000000000000000000000000000001"},
 		{"0000000000000000000000000000000000000000000000000000000000000001", "01", "0000000000000000000000000000000000000000000000000000000000000000"},
 		{"8000000000000000000000000000000000000000000000000000000000000000", "01", "c000000000000000000000000000000000000000000000000000000000000000"},
@@ -168,44 +205,58 @@ func TestSAR(t *testing.T) {
 		{"7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", "0100", "0000000000000000000000000000000000000000000000000000000000000000"},
 	}
 
-	testTwoOperandOp(t, tests, opSAR)
+	testTwoOperandOp(t, tests, opSAR, "sar")
 }
 
-func TestSGT(t *testing.T) {
-	tests := []twoOperandTest{
+// getResult is a convenience function to generate the expected values
+func getResult(args []*twoOperandParams, opFn executionFunc) []TwoOperandTestcase {
+	var (
+		env         = NewEVM(Context{}, nil, params.TestChainConfig, Config{})
+		stack       = newstack()
+		pc          = uint64(0)
+		interpreter = env.interpreter.(*EVMInterpreter)
+	)
+	interpreter.intPool = poolOfIntPools.get()
+	result := make([]TwoOperandTestcase, len(args))
+	for i, param := range args {
+		x := new(big.Int).SetBytes(common.Hex2Bytes(param.x))
+		y := new(big.Int).SetBytes(common.Hex2Bytes(param.y))
+		stack.push(x)
+		stack.push(y)
+		opFn(&pc, interpreter, nil, nil, stack)
+		actual := stack.pop()
+		result[i] = TwoOperandTestcase{param.x, param.y, fmt.Sprintf("%064x", actual)}
+	}
+	return result
+}
 
-		{"0000000000000000000000000000000000000000000000000000000000000001", "0000000000000000000000000000000000000000000000000000000000000001", "0000000000000000000000000000000000000000000000000000000000000000"},
-		{"ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", "0000000000000000000000000000000000000000000000000000000000000000"},
-		{"7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", "7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", "0000000000000000000000000000000000000000000000000000000000000000"},
-		{"0000000000000000000000000000000000000000000000000000000000000001", "7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", "0000000000000000000000000000000000000000000000000000000000000001"},
-		{"7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", "0000000000000000000000000000000000000000000000000000000000000001", "0000000000000000000000000000000000000000000000000000000000000000"},
-		{"ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", "0000000000000000000000000000000000000000000000000000000000000001", "0000000000000000000000000000000000000000000000000000000000000001"},
-		{"0000000000000000000000000000000000000000000000000000000000000001", "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", "0000000000000000000000000000000000000000000000000000000000000000"},
-		{"8000000000000000000000000000000000000000000000000000000000000001", "8000000000000000000000000000000000000000000000000000000000000001", "0000000000000000000000000000000000000000000000000000000000000000"},
-		{"8000000000000000000000000000000000000000000000000000000000000001", "7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", "0000000000000000000000000000000000000000000000000000000000000001"},
-		{"7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", "8000000000000000000000000000000000000000000000000000000000000001", "0000000000000000000000000000000000000000000000000000000000000000"},
-		{"fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffb", "fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffd", "0000000000000000000000000000000000000000000000000000000000000001"},
-		{"fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffd", "fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffb", "0000000000000000000000000000000000000000000000000000000000000000"},
+// utility function to fill the json-file with testcases
+// Enable this test to generate the 'testcases_xx.json' files
+func xTestWriteExpectedValues(t *testing.T) {
+	for name, method := range twoOpMethods {
+		data, err := json.Marshal(getResult(commonParams, method))
+		if err != nil {
+			t.Fatal(err)
+		}
+		_ = ioutil.WriteFile(fmt.Sprintf("testdata/testcases_%v.json", name), data, 0644)
+		if err != nil {
+			t.Fatal(err)
+		}
 	}
-	testTwoOperandOp(t, tests, opSgt)
-}
-
-func TestSLT(t *testing.T) {
-	tests := []twoOperandTest{
-		{"0000000000000000000000000000000000000000000000000000000000000001", "0000000000000000000000000000000000000000000000000000000000000001", "0000000000000000000000000000000000000000000000000000000000000000"},
-		{"ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", "0000000000000000000000000000000000000000000000000000000000000000"},
-		{"7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", "7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", "0000000000000000000000000000000000000000000000000000000000000000"},
-		{"0000000000000000000000000000000000000000000000000000000000000001", "7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", "0000000000000000000000000000000000000000000000000000000000000000"},
-		{"7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", "0000000000000000000000000000000000000000000000000000000000000001", "0000000000000000000000000000000000000000000000000000000000000001"},
-		{"ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", "0000000000000000000000000000000000000000000000000000000000000001", "0000000000000000000000000000000000000000000000000000000000000000"},
-		{"0000000000000000000000000000000000000000000000000000000000000001", "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", "0000000000000000000000000000000000000000000000000000000000000001"},
-		{"8000000000000000000000000000000000000000000000000000000000000001", "8000000000000000000000000000000000000000000000000000000000000001", "0000000000000000000000000000000000000000000000000000000000000000"},
-		{"8000000000000000000000000000000000000000000000000000000000000001", "7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", "0000000000000000000000000000000000000000000000000000000000000000"},
-		{"7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", "8000000000000000000000000000000000000000000000000000000000000001", "0000000000000000000000000000000000000000000000000000000000000001"},
-		{"fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffb", "fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffd", "0000000000000000000000000000000000000000000000000000000000000000"},
-		{"fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffd", "fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffb", "0000000000000000000000000000000000000000000000000000000000000001"},
+	t.Fatal("This test should not be activated")
+}
+
+// TestJsonTestcases runs through all the testcases defined as json-files
+func TestJsonTestcases(t *testing.T) {
+	for name := range twoOpMethods {
+		data, err := ioutil.ReadFile(fmt.Sprintf("testdata/testcases_%v.json", name))
+		if err != nil {
+			t.Fatal("Failed to read file", err)
+		}
+		var testcases []TwoOperandTestcase
+		json.Unmarshal(data, &testcases)
+		testTwoOperandOp(t, testcases, twoOpMethods[name], name)
 	}
-	testTwoOperandOp(t, tests, opSlt)
 }
 
 func opBenchmark(bench *testing.B, op func(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error), args ...string) {