Add blockhash to Solidity.

Autopadding fix.

libdevcore/CommonJS.h

@@ -65,7 +65,7 @@ template <unsigned N> FixedHash<N> jsToFixed(std::string const& _s)
 {
 	if (_s.substr(0, 2) == "0x")
 		// Hex
-		return FixedHash<N>(_s.substr(2));
+		return FixedHash<N>(_s.substr(2 + std::max<unsigned>(40, _s.size() - 2) - 40));
 	else if (_s.find_first_not_of("0123456789") == std::string::npos)
 		// Decimal
 		return (typename FixedHash<N>::Arith)(_s);

libsolidity/ExpressionCompiler.cpp

@@ -282,6 +282,13 @@ bool ExpressionCompiler::visit(FunctionCall const& _functionCall)
 			m_context << u256(32) << u256(0) << eth::logInstruction(logNumber);
 			break;
 		}
+		case Location::BLOCKHASH:
+		{
+			arguments[0]->accept(*this);
+			appendTypeConversion(*arguments[0]->getType(), *function.getParameterTypes()[0], true);
+			m_context << eth::Instruction::BLOCKHASH;
+			break;
+		}
 		case Location::ECRECOVER:
 		case Location::SHA256:
 		case Location::RIPEMD160:

libsolidity/Types.cpp

@@ -656,8 +656,8 @@ MagicType::MagicType(MagicType::Kind _kind):
 	{
 	case Kind::BLOCK:
 		m_members = MemberList({{"coinbase", make_shared<IntegerType>(0, IntegerType::Modifier::ADDRESS)},
-								{"timestamp", make_shared<IntegerType >(256)},
-								{"prevhash", make_shared<IntegerType>(256, IntegerType::Modifier::HASH)},
+								{"timestamp", make_shared<IntegerType>(256)},
+								{"blockhash", make_shared<FunctionType>(strings{"uint"}, strings{"hash"}, FunctionType::Location::BLOCKHASH)},
 								{"difficulty", make_shared<IntegerType>(256)},
 								{"number", make_shared<IntegerType>(256)},
 								{"gaslimit", make_shared<IntegerType>(256)}});

libsolidity/Types.h

@@ -348,7 +348,7 @@ public:
 	/// INTERNAL: jump tag, EXTERNAL: contract address + function index,
 	/// BARE: contract address (non-abi contract call)
 	/// OTHERS: special virtual function, nothing on the stack
-	enum class Location { INTERNAL, EXTERNAL, SEND, SHA3, SUICIDE, ECRECOVER, SHA256, RIPEMD160, LOG0, LOG1, LOG2, LOG3, LOG4, BARE };
+	enum class Location { INTERNAL, EXTERNAL, SEND, SHA3, SUICIDE, ECRECOVER, SHA256, RIPEMD160, LOG0, LOG1, LOG2, LOG3, LOG4, BLOCKHASH, BARE };
 
 	virtual Category getCategory() const override { return Category::FUNCTION; }
 	explicit FunctionType(FunctionDefinition const& _function, bool _isInternal = true);