console.log go brrr (#193)

Introduce `console.log` functionality with string formatting capabilities.

---------

Co-authored-by: David Pokora <dpokora@gmail.com>

chain/cheat_code_contract.go

@@ -54,6 +54,30 @@ type cheatCodeRawReturnData struct {
 	Err error
 }
 
+// getCheatCodeProviders obtains a cheatCodeTracer (used to power cheat code analysis) and associated CheatCodeContract
+// objects linked to the tracer (providing on-chain callable methods as an entry point). These objects are attached to
+// the TestChain to enable cheat code functionality.
+// Returns the tracer and associated pre-compile contracts, or an error, if one occurred.
+func getCheatCodeProviders() (*cheatCodeTracer, []*CheatCodeContract, error) {
+	// Create a cheat code tracer and attach it to the chain.
+	tracer := newCheatCodeTracer()
+
+	// Obtain our standard cheat code pre-compile
+	stdCheatCodeContract, err := getStandardCheatCodeContract(tracer)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	// Obtain the console.log pre-compile
+	consoleCheatCodeContract, err := getConsoleLogCheatCodeContract(tracer)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	// Return the tracer and precompiles
+	return tracer, []*CheatCodeContract{stdCheatCodeContract, consoleCheatCodeContract}, nil
+}
+
 // newCheatCodeContract returns a new precompiledContract which uses the attached cheatCodeTracer for execution
 // context.
 func newCheatCodeContract(tracer *cheatCodeTracer, address common.Address, name string) *CheatCodeContract {
@@ -98,7 +122,7 @@ func (c *CheatCodeContract) Abi() *abi.ABI {
 }
 
 // addMethod adds a new method to the precompiled contract.
-// Returns an error if one occurred.
+// Throws a panic if either the name is the empty string or the handler is nil.
 func (c *CheatCodeContract) addMethod(name string, inputs abi.Arguments, outputs abi.Arguments, handler cheatCodeMethodHandler) {
 	// Verify a method name was provided
 	if name == "" {
@@ -117,7 +141,6 @@ func (c *CheatCodeContract) addMethod(name string, inputs abi.Arguments, outputs
 		method:  method,
 		handler: handler,
 	}
-
 	// Add the method to the ABI.
 	// Note: Normally the key here should be the method name, not sig. But cheat code contracts have duplicate
 	// method names with different parameter types, so we use this so they don't override.

chain/console_log_cheat_code_contract.go

@@ -0,0 +1,124 @@
+package chain
+
+import (
+	"github.com/crytic/medusa/utils"
+	"github.com/ethereum/go-ethereum/accounts/abi"
+	"github.com/ethereum/go-ethereum/common"
+	"strconv"
+)
+
+// ConsoleLogContractAddress is the address for the console.log precompile contract
+var ConsoleLogContractAddress = common.HexToAddress("0x000000000000000000636F6e736F6c652e6c6f67")
+
+// getConsoleLogCheatCodeContract obtains a CheatCodeContract which implements the console.log functions.
+// Returns the precompiled contract, or an error if there is one.
+func getConsoleLogCheatCodeContract(tracer *cheatCodeTracer) (*CheatCodeContract, error) {
+	// Create a new precompile to add methods to.
+	contract := newCheatCodeContract(tracer, ConsoleLogContractAddress, "Console")
+
+	// Define all the ABI types needed for console.log functions
+	typeUint256, err := abi.NewType("uint256", "", nil)
+	if err != nil {
+		return nil, err
+	}
+	typeInt256, err := abi.NewType("int256", "", nil)
+	if err != nil {
+		return nil, err
+	}
+	typeString, err := abi.NewType("string", "", nil)
+	if err != nil {
+		return nil, err
+	}
+	typeBool, err := abi.NewType("bool", "", nil)
+	if err != nil {
+		return nil, err
+	}
+	typeAddress, err := abi.NewType("address", "", nil)
+	if err != nil {
+		return nil, err
+	}
+	typeBytes, err := abi.NewType("bytes", "", nil)
+	if err != nil {
+		return nil, err
+	}
+
+	// We will store all the fixed byte (e.g. byte1, byte2) in a mapping
+	const numFixedByteTypes = 32
+	fixedByteTypes := make(map[int]abi.Type, numFixedByteTypes)
+	for i := 1; i <= numFixedByteTypes; i++ {
+		byteString := "bytes" + strconv.FormatInt(int64(i), 10)
+		fixedByteTypes[i], err = abi.NewType(byteString, "", nil)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	// We have a few special log function signatures outside all the permutations of (string, uint256, bool, address).
+	// These include log(int256), log(bytes), log(bytesX), and log(string, uint256). So, we will manually create these
+	// signatures and then programmatically iterate through all the permutations.
+
+	// Note that none of the functions actually do anything - they just have to be callable so that the execution
+	// traces can show the arguments that the user wants to log!
+
+	// log(int256): Log an int256
+	contract.addMethod("log", abi.Arguments{{Type: typeInt256}}, abi.Arguments{},
+		func(tracer *cheatCodeTracer, inputs []any) ([]any, *cheatCodeRawReturnData) {
+			return nil, nil
+		},
+	)
+
+	// log(bytes): Log bytes
+	contract.addMethod("log", abi.Arguments{{Type: typeBytes}}, abi.Arguments{},
+		func(tracer *cheatCodeTracer, inputs []any) ([]any, *cheatCodeRawReturnData) {
+			return nil, nil
+		},
+	)
+
+	// Now, we will add the logBytes1, logBytes2, and so on in a loop
+	for i := 1; i <= numFixedByteTypes; i++ {
+		// Create local copy of abi argument
+		fixedByteType := fixedByteTypes[i]
+
+		// Add the method
+		contract.addMethod("log", abi.Arguments{{Type: fixedByteType}}, abi.Arguments{},
+			func(tracer *cheatCodeTracer, inputs []any) ([]any, *cheatCodeRawReturnData) {
+				return nil, nil
+			},
+		)
+	}
+
+	// log(string, int256): Log string with an int where the string could be formatted
+	contract.addMethod("log", abi.Arguments{{Type: typeString}, {Type: typeInt256}}, abi.Arguments{},
+		func(tracer *cheatCodeTracer, inputs []any) ([]any, *cheatCodeRawReturnData) {
+			return nil, nil
+		},
+	)
+
+	// These are the four parameter types that console.log() accepts
+	choices := abi.Arguments{{Type: typeUint256}, {Type: typeString}, {Type: typeBool}, {Type: typeAddress}}
+
+	// Create all possible permutations (with repetition) where the number of choices increases from 1...len(choices)
+	permutations := make([]abi.Arguments, 0)
+	for n := 1; n <= len(choices); n++ {
+		nextSetOfPermutations := utils.PermutationsWithRepetition(choices, n)
+		for _, permutation := range nextSetOfPermutations {
+			permutations = append(permutations, permutation)
+		}
+	}
+
+	// Iterate across each permutation to add their associated event and function handler
+	for i := 0; i < len(permutations); i++ {
+		// Make a local copy of the current permutation
+		permutation := permutations[i]
+
+		// Create the function handler
+		contract.addMethod("log", permutation, abi.Arguments{},
+			func(tracer *cheatCodeTracer, inputs []any) ([]any, *cheatCodeRawReturnData) {
+				return nil, nil
+			},
+		)
+	}
+
+	// Return our precompile contract information.
+	return contract, nil
+}

chain/cheat_codes.go → chain/standard_cheat_code_contract.go

@@ -14,30 +14,14 @@ import (
 	"strings"
 )
 
-// getCheatCodeProviders obtains a cheatCodeTracer (used to power cheat code analysis) and associated CheatCodeContract
-// objects linked to the tracer (providing on-chain callable methods as an entry point). These objects are attached to
-// the TestChain to enable cheat code functionality.
-// Returns the tracer and associated pre-compile contracts, or an error, if one occurred.
-func getCheatCodeProviders() (*cheatCodeTracer, []*CheatCodeContract, error) {
-	// Create a cheat code tracer and attach it to the chain.
-	tracer := newCheatCodeTracer()
-
-	// Obtain our cheat code pre-compiles
-	stdCheatCodeContract, err := getStandardCheatCodeContract(tracer)
-	if err != nil {
-		return nil, nil, err
-	}
-
-	// Return the tracer and precompiles
-	return tracer, []*CheatCodeContract{stdCheatCodeContract}, nil
-}
+// StandardCheatcodeContractAddress is the address for the standard cheatcode contract
+var StandardCheatcodeContractAddress = common.HexToAddress("0x7109709ECfa91a80626fF3989D68f67F5b1DD12D")
 
 // getStandardCheatCodeContract obtains a CheatCodeContract which implements common cheat codes.
 // Returns the precompiled contract, or an error if one occurs.
 func getStandardCheatCodeContract(tracer *cheatCodeTracer) (*CheatCodeContract, error) {
-	// Define our address for this precompile contract, then create a new precompile to add methods to.
-	contractAddress := common.HexToAddress("0x7109709ECfa91a80626fF3989D68f67F5b1DD12D")
-	contract := newCheatCodeContract(tracer, contractAddress, "StdCheats")
+	// Create a new precompile to add methods to.
+	contract := newCheatCodeContract(tracer, StandardCheatcodeContractAddress, "StdCheats")
 
 	// Define some basic ABI argument types
 	typeAddress, err := abi.NewType("address", "", nil)

compilation/abiutils/solidity_errors.go

@@ -113,25 +113,25 @@ func GetPanicReason(panicCode uint64) string {
 	// Switch on panic code
 	switch panicCode {
 	case PanicCodeCompilerInserted:
-		return "compiler inserted panic"
+		return "panic: compiler inserted panic"
 	case PanicCodeAssertFailed:
-		return "assertion failed"
+		return "panic: assertion failed"
 	case PanicCodeArithmeticUnderOverflow:
-		return "arithmetic underflow"
+		return "panic: arithmetic underflow"
 	case PanicCodeDivideByZero:
-		return "division by zero"
+		return "panic: division by zero"
 	case PanicCodeEnumTypeConversionOutOfBounds:
-		return "enum access out of bounds"
+		return "panic: enum access out of bounds"
 	case PanicCodeIncorrectStorageAccess:
-		return "incorrect storage access"
+		return "panic: incorrect storage access"
 	case PanicCodePopEmptyArray:
-		return "pop on empty array"
+		return "panic: pop on empty array"
 	case PanicCodeOutOfBoundsArrayAccess:
-		return "out of bounds array access"
+		return "panic: out of bounds array access"
 	case PanicCodeAllocateTooMuchMemory:
-		return "overallocation of memory"
+		return "panic; overallocation of memory"
 	case PanicCodeCallUninitializedVariable:
-		return "call on uninitialized variable"
+		return "panic: call on uninitialized variable"
 	default:
 		return fmt.Sprintf("unknown panic code(%v)", panicCode)
 	}