Merge pull request #6456 from ethereum/fixFunctionRegistration

[Yul] Fix registration of functions in scopes.

Changelog.md

@@ -22,6 +22,7 @@ Compiler Features:
 Bugfixes:
  * SMTChecker: Implement Boolean short-circuiting.
  * SMTChecker: SSA control-flow did not take into account state variables that were modified inside inlined functions that were called inside branches.
+ * Yul: Properly register functions and disallow shadowing between function variables and variables in the outside scope.
 
 
 

libyul/AsmScope.cpp

@@ -42,11 +42,11 @@ bool Scope::registerVariable(YulString _name, YulType const& _type)
 	return true;
 }
 
-bool Scope::registerFunction(YulString _name, std::vector<YulType> const& _arguments, std::vector<YulType> const& _returns)
+bool Scope::registerFunction(YulString _name, std::vector<YulType> _arguments, std::vector<YulType> _returns)
 {
 	if (exists(_name))
 		return false;
-	identifiers[_name] = Function{_arguments, _returns};
+	identifiers[_name] = Function{std::move(_arguments), std::move(_returns)};
 	return true;
 }
 

libyul/AsmScope.h

@@ -56,8 +56,8 @@ struct Scope
 	bool registerLabel(YulString _name);
 	bool registerFunction(
 		YulString _name,
-		std::vector<YulType> const& _arguments,
+		std::vector<YulType> _arguments,
-		std::vector<YulType> const& _returns
+		std::vector<YulType> _returns
 	);
 
 	/// Looks up the identifier in this or super scopes and returns a valid pointer if found

libyul/AsmScopeFiller.cpp

@@ -74,28 +74,13 @@ bool ScopeFiller::operator()(VariableDeclaration const& _varDecl)
 
 bool ScopeFiller::operator()(FunctionDefinition const& _funDef)
 {
-	bool success = true;
-	vector<Scope::YulType> arguments;
-	for (auto const& _argument: _funDef.parameters)
-		arguments.emplace_back(_argument.type.str());
-	vector<Scope::YulType> returns;
-	for (auto const& _return: _funDef.returnVariables)
-		returns.emplace_back(_return.type.str());
-	if (!m_currentScope->registerFunction(_funDef.name, arguments, returns))
-	{
-		//@TODO secondary location
-		m_errorReporter.declarationError(
-			_funDef.location,
-			"Function name " + _funDef.name.str() + " already taken in this scope."
-		);
-		success = false;
-	}
-
 	auto virtualBlock = m_info.virtualBlocks[&_funDef] = make_shared<Block>();
 	Scope& varScope = scope(virtualBlock.get());
 	varScope.superScope = m_currentScope;
 	m_currentScope = &varScope;
 	varScope.functionScope = true;
+
+	bool success = true;
 	for (auto const& var: _funDef.parameters + _funDef.returnVariables)
 		if (!registerVariable(var, _funDef.location, varScope))
 			success = false;
@@ -153,10 +138,9 @@ bool ScopeFiller::operator()(Block const& _block)
 	// an entry in the scope according to their visibility.
 	for (auto const& s: _block.statements)
 		if (s.type() == typeid(FunctionDefinition))
-			if (!boost::apply_visitor(*this, s))
+			if (!registerFunction(boost::get<FunctionDefinition>(s)))
 				success = false;
 	for (auto const& s: _block.statements)
-		if (s.type() != typeid(FunctionDefinition))
 		if (!boost::apply_visitor(*this, s))
 			success = false;
 
@@ -178,6 +162,26 @@ bool ScopeFiller::registerVariable(TypedName const& _name, SourceLocation const&
 	return true;
 }
 
+bool ScopeFiller::registerFunction(FunctionDefinition const& _funDef)
+{
+	vector<Scope::YulType> arguments;
+	for (auto const& _argument: _funDef.parameters)
+		arguments.emplace_back(_argument.type.str());
+	vector<Scope::YulType> returns;
+	for (auto const& _return: _funDef.returnVariables)
+		returns.emplace_back(_return.type.str());
+	if (!m_currentScope->registerFunction(_funDef.name, std::move(arguments), std::move(returns)))
+	{
+		//@TODO secondary location
+		m_errorReporter.declarationError(
+			_funDef.location,
+			"Function name " + _funDef.name.str() + " already taken in this scope."
+		);
+		return false;
+	}
+	return true;
+}
+
 Scope& ScopeFiller::scope(Block const* _block)
 {
 	auto& scope = m_info.scopes[_block];

libyul/AsmScopeFiller.h

@@ -73,6 +73,7 @@ private:
 		langutil::SourceLocation const& _location,
 		Scope& _scope
 	);
+	bool registerFunction(FunctionDefinition const& _funDef);
 
 	Scope& scope(Block const* _block);
 

libyul/optimiser/Suite.cpp

@@ -198,6 +198,7 @@ void OptimiserSuite::run(
 	BlockFlattener{}(ast);
 	DeadCodeEliminator{}(ast);
 
+	FunctionGrouper{}(ast);
 	VarNameCleaner{ast, *_dialect, reservedIdentifiers}(ast);
 	yul::AsmAnalyzer::analyzeStrictAssertCorrect(_dialect, ast);
 

libyul/optimiser/VarNameCleaner.h

@@ -38,7 +38,7 @@ struct Dialect;
  * renumbered by their base name.
  * Function names are not modified.
  *
- * Prerequisites: Disambiguator, FunctionHoister
+ * Prerequisites: Disambiguator, FunctionHoister, FunctionGrouper
  */
 class VarNameCleaner: public ASTModifier
 {

test/cmdlineTests.sh

@@ -343,7 +343,7 @@ printTask "Testing assemble, yul, strict-assembly and optimize..."
     # while it results in empty binary representation with optimizations turned on.
     test_solc_assembly_output "{ let x:u256 := 0:u256 }" "{ let x:u256 := 0:u256 }" "--yul"
     test_solc_assembly_output "{ let x := 0 }" "{ let x := 0 }" "--strict-assembly"
-    test_solc_assembly_output "{ let x := 0 }" "{ }" "--strict-assembly --optimize"
+    test_solc_assembly_output "{ let x := 0 }" "{ { } }" "--strict-assembly --optimize"
 )
 
 

test/cmdlineTests/object_compiler/output

@@ -4,18 +4,22 @@
 Pretty printed source:
 object "MyContract" {
     code {
+        {
             sstore(0, caller())
             let _1 := datasize("Runtime")
             datacopy(0, dataoffset("Runtime"), _1)
             return(0, _1)
         }
+    }
     object "Runtime" {
         code {
+            {
                 mstore(0, sload(0))
                 return(0, 0x20)
             }
         }
     }
+}
 
 
 Binary representation:

test/cmdlineTests/standard_yul_optimized/output.json

@@ -1 +1 @@
-{"contracts":{"A":{"object":{"evm":{"assembly":"    /* \"A\":17:18   */\n  0x00\n  0x00\n    /* \"A\":11:19   */\n  mload\n    /* \"A\":20:40   */\n  sstore\n","bytecode":{"linkReferences":{},"object":"600060005155","opcodes":"PUSH1 0x0 PUSH1 0x0 MLOAD SSTORE ","sourceMap":""}},"ir":"object \"object\" {\n    code {\n        let x := mload(0)\n        sstore(add(x, 0), 0)\n    }\n}\n","irOptimized":"object \"object\" {\n    code {\n        sstore(mload(0), 0)\n    }\n}\n"}}},"errors":[{"component":"general","formattedMessage":"Yul is still experimental. Please use the output with care.","message":"Yul is still experimental. Please use the output with care.","severity":"warning","type":"Warning"}]}
+{"contracts":{"A":{"object":{"evm":{"assembly":"    /* \"A\":17:18   */\n  0x00\n  0x00\n    /* \"A\":11:19   */\n  mload\n    /* \"A\":20:40   */\n  sstore\n","bytecode":{"linkReferences":{},"object":"600060005155","opcodes":"PUSH1 0x0 PUSH1 0x0 MLOAD SSTORE ","sourceMap":""}},"ir":"object \"object\" {\n    code {\n        let x := mload(0)\n        sstore(add(x, 0), 0)\n    }\n}\n","irOptimized":"object \"object\" {\n    code {\n        {\n            sstore(mload(0), 0)\n        }\n    }\n}\n"}}},"errors":[{"component":"general","formattedMessage":"Yul is still experimental. Please use the output with care.","message":"Yul is still experimental. Please use the output with care.","severity":"warning","type":"Warning"}]}

test/cmdlineTests/yul_stack_opt/output

@@ -4,9 +4,11 @@
 Pretty printed source:
 object "object" {
     code {
+        {
             let a1, b1, c1, d1, e1, f1, g1, h1, i1, j1, k1, l1, m1, n1, o1, p1 := fun()
             let a2, b2, c2, d2, e2, f2, g2, h2, i2, j2, k2, l2, m2, n2, o2, p2 := fun()
             sstore(a1, a2)
+        }
         function fun() -> a3, b3, c3, d3, e3, f3, g3, h3, i3, j3, k3, l3, m3, n3, o3, p3
         {
             let a := 1

test/libyul/Parser.cpp

@@ -390,6 +390,12 @@ BOOST_AUTO_TEST_CASE(switch_duplicate_case_different_literal)
 	BOOST_CHECK(successParse("{ switch 1:u256 case \"1\":u256 {} case \"2\":u256 {} }"));
 }
 
+BOOST_AUTO_TEST_CASE(function_shadowing_outside_vars)
+{
+	CHECK_ERROR("{ let x:u256 function f() -> x:u256 {} }", DeclarationError, "already taken in this scope");
+	BOOST_CHECK(successParse("{ { let x:u256 } function f() -> x:u256 {} }"));
+}
+
 BOOST_AUTO_TEST_CASE(builtins_parser)
 {
 	struct SimpleDialect: public Dialect

test/libyul/yulOptimizerTests/fullSuite/abi2.yul

@@ -1073,6 +1073,7 @@
 // step: fullSuite
 // ----
 // {
+//     {
 //         let _1 := mload(1)
 //         let _2 := mload(0)
 //         if slt(sub(_1, _2), 64)
@@ -1085,6 +1086,7 @@
 //         sstore(x3, x2)
 //         sstore(1, x4)
 //         pop(abi_encode_tuple_t_bytes32_t_address_t_uint256_t_bytes32_t_enum$_Operation_$1949_t_uint256_t_uint256_t_uint256_t_address_t_address_t_uint256__to_t_bytes32_t_address_t_uint256_t_bytes32_t_uint8_t_uint256_t_uint256_t_uint256_t_address_t_address_t_uint256_(mload(30), mload(31), mload(32), mload(33), mload(34), mload(35), mload(36), mload(37), mload(38), mload(39), mload(40), mload(41)))
+//     }
 //     function abi_decode_tuple_t_addresst_uint256t_bytes_calldata_ptrt_enum$_Operation_$1949(headStart, dataEnd) -> value0, value1, value2, value3, value4
 //     {
 //         if slt(sub(dataEnd, headStart), 128)

test/libyul/yulOptimizerTests/fullSuite/abi_example1.yul

@@ -459,6 +459,7 @@
 // step: fullSuite
 // ----
 // {
+//     {
 //         let _1 := 0x20
 //         let _2 := 0
 //         let _3 := mload(_2)
@@ -515,6 +516,7 @@
 //         sstore(calldataload(_6), calldataload(add(_6, _1)))
 //         sstore(value2, value3)
 //         sstore(_2, pos)
+//     }
 //     function abi_decode_t_array$_t_array$_t_uint256_$2_memory_$dyn_memory_ptr(offset, end) -> array
 //     {
 //         if iszero(slt(add(offset, 0x1f), end))

test/libyul/yulOptimizerTests/fullSuite/aztec.yul

@@ -232,6 +232,7 @@
 // step: fullSuite
 // ----
 // {
+//     {
 //         mstore(0x80, 7673901602397024137095011250362199966051872585513276903826533215767972925880)
 //         mstore(0xa0, 8489654445897228341090914135473290831551238522473825886865492707826370766375)
 //         let notes := add(0x04, calldataload(0x04))
@@ -333,6 +334,7 @@
 //         }
 //         mstore(i_1, 0x01)
 //         return(i_1, 0x20)
+//     }
 //     function validatePairing(t2)
 //     {
 //         let t2_x := calldataload(t2)

test/libyul/yulOptimizerTests/fullSuite/medium.yul

@@ -20,6 +20,7 @@
 // step: fullSuite
 // ----
 // {
+//     {
 //         let _1 := 0x40
 //         mstore(_1, add(mload(_1), 0x20))
 //         let p := mload(_1)
@@ -27,3 +28,4 @@
 //         mstore(add(p, 96), 2)
 //         mstore(_1, 0x20)
 //     }
+// }

test/libyul/yulOptimizerTests/fullSuite/reuse_vars_bug_in_simplifier.yul

@@ -13,5 +13,7 @@
 // step: fullSuite
 // ----
 // {
+//     {
 //         mstore(1, 1)
 //     }
+// }

test/libyul/yulOptimizerTests/fullSuite/ssaReverse.yul

@@ -35,6 +35,7 @@
 // step: fullSuite
 // ----
 // {
+//     {
 //         let a, b := abi_decode_t_bytes_calldata_ptr(mload(0), mload(1))
 //         let a_1, b_1 := abi_decode_t_bytes_calldata_ptr(a, b)
 //         let a_2, b_2 := abi_decode_t_bytes_calldata_ptr(a_1, b_1)
@@ -43,6 +44,7 @@
 //         let a_5, b_5 := abi_decode_t_bytes_calldata_ptr(a_4, b_4)
 //         let a_6, b_6 := abi_decode_t_bytes_calldata_ptr(a_5, b_5)
 //         mstore(a_6, b_6)
+//     }
 //     function abi_decode_t_bytes_calldata_ptr(offset, end) -> arrayPos, length
 //     {
 //         if iszero(slt(add(offset, 0x1f), end))

test/libyul/yulOptimizerTests/fullSuite/ssaReverseComplex.yul

@@ -13,6 +13,7 @@
 // step: fullSuite
 // ----
 // {
+//     {
 //         let a := mload(0)
 //         let b := mload(1)
 //         if mload(2)
@@ -22,3 +23,4 @@
 //         }
 //         mstore(a, b)
 //     }
+// }

test/libyul/yulOptimizerTests/fullSuite/switch_inline.yul

@@ -10,5 +10,7 @@
 // step: fullSuite
 // ----
 // {
+//     {
 //         mstore(9, 0)
 //     }
+// }

test/libyul/yulOptimizerTests/fullSuite/switch_inline_match_default.yul

@@ -11,5 +11,7 @@
 // step: fullSuite
 // ----
 // {
+//     {
 //         mstore(10, 0)
 //     }
+// }

test/libyul/yulOptimizerTests/ssaTransform/multi_decl.yul

@@ -4,22 +4,22 @@
   y := mload(x)
   let a, b := f(x, y)
   sstore(a, b)
-  function f(t, v) -> x, y {}
+  function f(t, v) -> w, z {}
 }
 // ====
 // step: ssaTransform
 // ----
 // {
-//     let x_2, y_3 := f(1, 2)
+//     let x_1, y_2 := f(1, 2)
-//     let x := x_2
+//     let x := x_1
-//     let y := y_3
+//     let y := y_2
-//     let x_4 := mload(y_3)
+//     let x_3 := mload(y_2)
-//     x := x_4
+//     x := x_3
-//     let y_5 := mload(x_4)
+//     let y_4 := mload(x_3)
-//     y := y_5
+//     y := y_4
-//     let a, b := f(x_4, y_5)
+//     let a, b := f(x_3, y_4)
 //     sstore(a, b)
-//     function f(t, v) -> x_1, y_2
+//     function f(t, v) -> w, z
 //     {
 //     }
 // }