EVM instruction interpreter: record linker symbols

Author: clonker

test/tools/yulInterpreter/EVMInstructionInterpreter.cpp

@@ -534,7 +534,8 @@ u256 EVMInstructionInterpreter::evalBuiltin(
 			return u256(keccak256(arg)) & 0xfff;
 		}
 	}
-	else if (fun == "datacopy")
+
+	if (fun == "datacopy")
 	{
 		// This is identical to codecopy.
 		if (
@@ -550,11 +551,21 @@ u256 EVMInstructionInterpreter::evalBuiltin(
 			);
 		return 0;
 	}
-	else if (fun == "memoryguard")
+
+	if (fun == "memoryguard")
 		return _evaluatedArguments.at(0);
-	else
-		yulAssert(false, "Unknown builtin: " + fun);
-	return 0;
+
+	if (fun == "linkersymbol")
+	{
+		yulAssert(_arguments.size() == 1);
+		yulAssert(std::holds_alternative<Literal>(_arguments[0]));
+		std::string const placeholder = formatLiteral(std::get<Literal>(_arguments[0]));
+		h256 const identifier(keccak256(placeholder));
+		m_linkerSymbols.emplace(identifier, placeholder);
+		return 0;
+	}
+
+	yulAssert(false, "Unknown builtin: " + fun);
 }
 
 

test/tools/yulInterpreter/EVMInstructionInterpreter.h

@@ -168,6 +168,10 @@ class EVMInstructionInterpreter
 	InterpreterState& m_state;
 	/// Flag to disable trace of instructions that write to memory.
 	bool m_disableMemoryWriteInstructions;
+	/// mapping from linker identifier (hash of literal) to original string representation, populated by linkersymbol
+	/// calls
+	std::map<util::h256, std::string> m_linkerSymbols;
+
 public:
 	/// Maximum length for range-based memory access operations.
 	static constexpr unsigned s_maxRangeSize = 0xffff;