Maintain disambiguation when generating new functions in StackToMemoryMover.

Author: ekpyron

libyul/optimiser/StackToMemoryMover.cpp

@@ -158,6 +158,12 @@ void StackToMemoryMover::operator()(FunctionDefinition& _functionDefinition)
 			{},
 			move(_functionDefinition.body)
 		});
+		// Generate new names for the arguments to maintain disambiguation.
+		std::map<YulString, YulString> newArgumentNames;
+		for (TypedName const& _var: stackParameters)
+			newArgumentNames[_var.name] = m_context.dispenser.newName(_var.name);
+		for (auto& parameter: _functionDefinition.parameters)
+			parameter.name = util::valueOrDefault(newArgumentNames, parameter.name, parameter.name);
 		// Replace original function by a call to the new function and an assignment to the return variable from memory.
 		_functionDefinition.body = Block{_functionDefinition.debugData, move(memoryVariableInits)};
 		_functionDefinition.body.statements.emplace_back(ExpressionStatement{
@@ -166,7 +172,7 @@ void StackToMemoryMover::operator()(FunctionDefinition& _functionDefinition)
 				_functionDefinition.debugData,
 				Identifier{_functionDefinition.debugData, newFunctionName},
 				stackParameters | ranges::views::transform([&](TypedName const& _arg) {
-					return Expression{Identifier{_arg.debugData, _arg.name}};
+					return Expression{Identifier{_arg.debugData, newArgumentNames.at(_arg.name)}};
 				}) | ranges::to<vector<Expression>>
 			}
 		});

test/libyul/yulOptimizerTests/fakeStackLimitEvader/return_one_with_args.yul

@@ -0,0 +1,38 @@
+{
+    {
+        mstore(0x40, memoryguard(0x80))
+        sstore(0, f(1,2,3))
+    }
+    function f(a, b, c) -> $b1 {
+        if calldataload(add(sub(a,b),c)) {
+            $b1 := 0
+            leave
+        }
+        $b1 := 1
+    }
+
+}
+// ----
+// step: fakeStackLimitEvader
+//
+// {
+//     {
+//         mstore(0x40, memoryguard(0xa0))
+//         sstore(0, f(1, 2, 3))
+//     }
+//     function f(a_2, b_3, c_4) -> $b1
+//     {
+//         mstore(0x80, 0)
+//         f_1(a_2, b_3, c_4)
+//         $b1 := mload(0x80)
+//     }
+//     function f_1(a, b, c)
+//     {
+//         if calldataload(add(sub(a, b), c))
+//         {
+//             mstore(0x80, 0)
+//             leave
+//         }
+//         mstore(0x80, 1)
+//     }
+// }