Fix wrong native locations in optimized IR AST

Changelog.md

@@ -19,6 +19,7 @@ Bugfixes:
  * SMTChecker: Fix formatting of unary minus expressions in invariants.
  * SMTChecker: Fix internal compiler error when reporting proved targets for BMC engine.
  * TypeChecker: Fix segfault when assigning nested tuple to tuple.
+ * Yul AST: Fix ``nativeSrc`` attributes in optimized IR AST referring to locations in unoptimized IR.
  * Yul IR Code Generation: Deterministic order of Yul subobjects.
  * Yul Optimizer: Name simplification could lead to forbidden identifiers with a leading and/or trailing dot, e.g., ``x._`` would get simplified into ``x.``.
  * Yul Parser: Fix segfault when parsing very long location comments.

libsolidity/interface/CompilerStack.cpp

@@ -1464,25 +1464,36 @@ void CompilerStack::generateIR(ContractDefinition const& _contract)
 		);
 	}
 
-	yul::YulStack stack(
-		m_evmVersion,
-		m_eofVersion,
-		yul::YulStack::Language::StrictAssembly,
-		m_optimiserSettings,
-		m_debugInfoSelection
-	);
-	bool yulAnalysisSuccessful = stack.parseAndAnalyze("", compiledContract.yulIR);
-	solAssert(
-		yulAnalysisSuccessful,
-		compiledContract.yulIR + "\n\n"
-		"Invalid IR generated:\n" +
-		langutil::SourceReferenceFormatter::formatErrorInformation(stack.errors(), stack) + "\n"
-	);
+	auto const parseYul = [&](std::string const& _irSource) {
+		YulStack stack(
+			m_evmVersion,
+			m_eofVersion,
+			YulStack::Language::StrictAssembly,
+			m_optimiserSettings,
+			m_debugInfoSelection
+		);
+		bool yulAnalysisSuccessful = stack.parseAndAnalyze("", _irSource);
+		solAssert(
+			yulAnalysisSuccessful,
+			_irSource + "\n\n"
+			"Invalid IR generated:\n" +
+			langutil::SourceReferenceFormatter::formatErrorInformation(stack.errors(), stack) + "\n"
+		);
+		return stack;
+	};
 
-	compiledContract.yulIRAst = stack.astJson();
-	stack.optimize();
-	compiledContract.yulIROptimized = stack.print(this);
-	compiledContract.yulIROptimizedAst = stack.astJson();
+	{
+		YulStack stack = parseYul(compiledContract.yulIR);
+		compiledContract.yulIRAst = stack.astJson();
+		stack.optimize();
+		compiledContract.yulIROptimized = stack.print(this);
+	}
+	{
+		// Optimizer does not maintain correct native source locations in the AST.
+		// We can work around it by regenerating the AST from scratch from optimized IR.
+		YulStack stack = parseYul(compiledContract.yulIROptimized);
+		compiledContract.yulIROptimizedAst = stack.astJson();
+	}
 }
 
 void CompilerStack::generateEVMFromIR(ContractDefinition const& _contract)

libyul/YulStack.cpp

@@ -44,6 +44,7 @@ using namespace solidity;
 using namespace solidity::frontend;
 using namespace solidity::yul;
 using namespace solidity::langutil;
+using namespace solidity::util;
 
 namespace
 {
@@ -257,8 +258,7 @@ MachineAssemblyObject YulStack::assemble(Machine _machine)
 	case Machine::EVM:
 		return assembleWithDeployed().first;
 	}
-	// unreachable
-	return MachineAssemblyObject();
+	unreachable();
 }
 
 std::pair<MachineAssemblyObject, MachineAssemblyObject>

libyul/YulStack.h

@@ -163,8 +163,6 @@ class YulStack: public langutil::CharStreamProvider
 	std::shared_ptr<yul::Object> m_parserResult;
 	langutil::ErrorList m_errors;
 	langutil::ErrorReporter m_errorReporter;
-
-	std::unique_ptr<std::string> m_sourceMappings;
 };
 
 }