Merge pull request #15162 from ethereum/do-not-optimize-without-optimized-outputs

Do not optimize IR without optimized outputs

Author: cameel

Changelog.md

@@ -7,10 +7,12 @@ Language Features:
 
 
 Compiler Features:
+ * Command Line Interface: Do not perform IR optimization when only unoptimized IR is requested.
  * Error Reporting: Unimplemented features are now properly reported as errors instead of being handled as if they were bugs.
  * EVM: Support for the EVM version "Prague".
  * SMTChecker: Add CHC engine check for underflow and overflow in unary minus operation.
  * SMTChecker: Replace CVC4 as a possible BMC backend with cvc5.
+ * Standard JSON Interface: Do not perform IR optimization when only unoptimized IR is requested.
  * Yul Optimizer: The optimizer now treats some previously unrecognized identical literals as identical.
 
 

libsolidity/interface/CompilerStack.cpp

@@ -313,7 +313,7 @@ void CompilerStack::reset(bool _keepSettings)
 		m_viaIR = false;
 		m_evmVersion = langutil::EVMVersion();
 		m_modelCheckerSettings = ModelCheckerSettings{};
-		m_generateIR = false;
+		m_irOutputSelection = IROutputSelection::None;
 		m_revertStrings = RevertStrings::Default;
 		m_optimiserSettings = OptimiserSettings::minimal();
 		m_metadataLiteralSources = false;
@@ -728,8 +728,17 @@ bool CompilerStack::compile(State _stopAfter)
 				{
 					try
 					{
-						if ((m_generateEvmBytecode && m_viaIR) || m_generateIR)
-							generateIR(*contract);
+						// NOTE: Bytecode generation via IR always uses Contract::yulIROptimized.
+						// When optimization is not enabled, that member simply contains unoptimized code.
+						bool needIROutput =
+							(m_generateEvmBytecode && m_viaIR) ||
+							m_irOutputSelection != IROutputSelection::None;
+						bool needUnoptimizedIROutputOnly =
+							!(m_generateEvmBytecode && m_viaIR) &&
+							m_irOutputSelection != IROutputSelection::UnoptimizedAndOptimized;
+
+						if (needIROutput)
+							generateIR(*contract, needUnoptimizedIROutputOnly);
 						if (m_generateEvmBytecode)
 						{
 							if (m_viaIR)
@@ -1402,7 +1411,7 @@ void CompilerStack::compileContract(
 	assembleYul(_contract, compiler->assemblyPtr(), compiler->runtimeAssemblyPtr());
 }
 
-void CompilerStack::generateIR(ContractDefinition const& _contract)
+void CompilerStack::generateIR(ContractDefinition const& _contract, bool _unoptimizedOnly)
 {
 	solAssert(m_stackState >= AnalysisSuccessful, "");
 
@@ -1420,7 +1429,7 @@ void CompilerStack::generateIR(ContractDefinition const& _contract)
 
 	std::string dependenciesSource;
 	for (auto const& [dependency, referencee]: _contract.annotation().contractDependencies)
-		generateIR(*dependency);
+		generateIR(*dependency, _unoptimizedOnly);
 
 	if (!_contract.canBeDeployed())
 		return;
@@ -1485,9 +1494,14 @@ void CompilerStack::generateIR(ContractDefinition const& _contract)
 	{
 		YulStack stack = parseYul(compiledContract.yulIR);
 		compiledContract.yulIRAst = stack.astJson();
-		stack.optimize();
-		compiledContract.yulIROptimized = stack.print(this);
+		if (!_unoptimizedOnly)
+		{
+			stack.optimize();
+			compiledContract.yulIROptimized = stack.print(this);
+		}
 	}
+
+	if (!_unoptimizedOnly)
 	{
 		// 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.

libsolidity/interface/CompilerStack.h

@@ -126,6 +126,12 @@ class CompilerStack: public langutil::CharStreamProvider, public evmasm::Abstrac
 		SolidityAST,
 	};
 
+	enum class IROutputSelection {
+		None,
+		UnoptimizedOnly,
+		UnoptimizedAndOptimized,
+	};
+
 	/// Creates a new compiler stack.
 	/// @param _readFile callback used to read files for import statements. Must return
 	/// and must not emit exceptions.
@@ -192,8 +198,14 @@ class CompilerStack: public langutil::CharStreamProvider, public evmasm::Abstrac
 	/// Enable EVM Bytecode generation. This is enabled by default.
 	void enableEvmBytecodeGeneration(bool _enable = true) { m_generateEvmBytecode = _enable; }
 
-	/// Enable generation of Yul IR code.
-	void enableIRGeneration(bool _enable = true) { m_generateIR = _enable; }
+	/// Enable generation of Yul IR code so that IR output can be safely requested for all contracts.
+	/// Note that IR may also be implicitly generated when not requested. In particular
+	/// @a setViaIR(true) requires access to the IR outputs for bytecode generation.
+	void requestIROutputs(IROutputSelection _selection = IROutputSelection::UnoptimizedAndOptimized)
+	{
+		solAssert(m_stackState < ParsedAndImported);
+		m_irOutputSelection = _selection;
+	}
 
 	/// @arg _metadataLiteralSources When true, store sources as literals in the contract metadata.
 	/// Must be set before parsing.
@@ -387,8 +399,8 @@ class CompilerStack: public langutil::CharStreamProvider, public evmasm::Abstrac
 		std::shared_ptr<evmasm::Assembly> evmRuntimeAssembly;
 		evmasm::LinkerObject object; ///< Deployment object (includes the runtime sub-object).
 		evmasm::LinkerObject runtimeObject; ///< Runtime object.
-		std::string yulIR; ///< Yul IR code.
-		std::string yulIROptimized; ///< Optimized Yul IR code.
+		std::string yulIR; ///< Yul IR code straight from the code generator.
+		std::string yulIROptimized; ///< Reparsed and possibly optimized Yul IR code.
 		Json yulIRAst; ///< JSON AST of Yul IR code.
 		Json yulIROptimizedAst; ///< JSON AST of optimized Yul IR code.
 		util::LazyInit<std::string const> metadata; ///< The metadata json that will be hashed into the chain.
@@ -449,8 +461,14 @@ class CompilerStack: public langutil::CharStreamProvider, public evmasm::Abstrac
 	);
 
 	/// Generate Yul IR for a single contract.
-	/// The IR is stored but otherwise unused.
-	void generateIR(ContractDefinition const& _contract);
+	/// Unoptimized IR is stored but otherwise unused, while optimized IR may be used for code
+	/// generation if compilation via IR is enabled. Note that whether "optimized IR" is actually
+	/// optimized depends on the optimizer settings.
+	/// @param _contract Contract to generate IR for.
+	/// @param _unoptimizedOnly If true, only the IR coming directly from the codegen is stored.
+	///     Optimizer is not invoked and optimized IR output is not available, which means that
+	///     optimized IR, its AST or compilation via IR must not be requested.
+	void generateIR(ContractDefinition const& _contract, bool _unoptimizedOnly);
 
 	/// Generate EVM representation for a single contract.
 	/// Depends on output generated by generateIR.
@@ -515,7 +533,7 @@ class CompilerStack: public langutil::CharStreamProvider, public evmasm::Abstrac
 	ModelCheckerSettings m_modelCheckerSettings;
 	std::map<std::string, std::set<std::string>> m_requestedContractNames;
 	bool m_generateEvmBytecode = true;
-	bool m_generateIR = false;
+	IROutputSelection m_irOutputSelection = IROutputSelection::None;
 	std::map<std::string, util::h160> m_libraries;
 	ImportRemapper m_importRemapper;
 	std::map<std::string const, Source> m_sources;

libsolidity/interface/StandardCompiler.cpp

@@ -295,25 +295,26 @@ bool isEvmBytecodeRequested(Json const& _outputSelection)
 	return false;
 }
 
-/// @returns true if any Yul IR was requested. Note that as an exception, '*' does not
-/// yet match "ir", "irAst", "irOptimized" or "irOptimizedAst"
-bool isIRRequested(Json const& _outputSelection)
+/// @returns The IR output selection for CompilerStack, based on outputs requested in the JSON.
+/// Note that as an exception, '*' does not yet match "ir", "irAst", "irOptimized" or "irOptimizedAst".
+CompilerStack::IROutputSelection irOutputSelection(Json const& _outputSelection)
 {
 	if (!_outputSelection.is_object())
-		return false;
+		return CompilerStack::IROutputSelection::None;
 
+	CompilerStack::IROutputSelection selection = CompilerStack::IROutputSelection::None;
 	for (auto const& fileRequests: _outputSelection)
 		for (auto const& requests: fileRequests)
 			for (auto const& request: requests)
-				if (
-					request == "ir" ||
-					request == "irAst" ||
-					request == "irOptimized" ||
-					request == "irOptimizedAst"
-				)
-					return true;
+			{
+				if (request == "irOptimized" || request == "irOptimizedAst")
+					return CompilerStack::IROutputSelection::UnoptimizedAndOptimized;
 
-	return false;
+				if (request == "ir" || request == "irAst")
+					selection = CompilerStack::IROutputSelection::UnoptimizedOnly;
+			}
+
+	return selection;
 }
 
 Json formatLinkReferences(std::map<size_t, std::string> const& linkReferences)
@@ -1320,7 +1321,7 @@ Json StandardCompiler::compileSolidity(StandardCompiler::InputsAndSettings _inpu
 	compilerStack.setModelCheckerSettings(_inputsAndSettings.modelCheckerSettings);
 
 	compilerStack.enableEvmBytecodeGeneration(isEvmBytecodeRequested(_inputsAndSettings.outputSelection));
-	compilerStack.enableIRGeneration(isIRRequested(_inputsAndSettings.outputSelection));
+	compilerStack.requestIROutputs(irOutputSelection(_inputsAndSettings.outputSelection));
 
 	Json errors = std::move(_inputsAndSettings.errors);
 

solc/CommandLineInterface.cpp

@@ -849,13 +849,14 @@ void CommandLineInterface::compile()
 		m_compiler->setRevertStringBehaviour(m_options.output.revertStrings);
 		if (m_options.output.debugInfoSelection.has_value())
 			m_compiler->selectDebugInfo(m_options.output.debugInfoSelection.value());
-		// TODO: Perhaps we should not compile unless requested
-		m_compiler->enableIRGeneration(
-			m_options.compiler.outputs.ir ||
-			m_options.compiler.outputs.irOptimized ||
-			m_options.compiler.outputs.irAstJson ||
-			m_options.compiler.outputs.irOptimizedAstJson
-		);
+
+		CompilerStack::IROutputSelection irOutputSelection = CompilerStack::IROutputSelection::None;
+		if (m_options.compiler.outputs.irOptimized || m_options.compiler.outputs.irOptimizedAstJson)
+			irOutputSelection = CompilerStack::IROutputSelection::UnoptimizedAndOptimized;
+		else if (m_options.compiler.outputs.ir || m_options.compiler.outputs.irAstJson)
+			irOutputSelection = CompilerStack::IROutputSelection::UnoptimizedOnly;
+
+		m_compiler->requestIROutputs(irOutputSelection);
 		m_compiler->enableEvmBytecodeGeneration(
 			m_options.compiler.estimateGas ||
 			m_options.compiler.outputs.asm_ ||

test/cmdlineTests/ir_optimized_with_optimize/args

@@ -0,0 +1 @@
+--ir-optimized --optimize --debug-info none

test/cmdlineTests/ir_optimized_with_optimize/input.sol

@@ -0,0 +1,4 @@
+// SPDX-License-Identifier: GPL-3.0
+pragma solidity *;
+
+contract C {}

test/cmdlineTests/ir_optimized_with_optimize/output

@@ -0,0 +1,19 @@
+Optimized IR:
+/// @use-src 0:"ir_optimized_with_optimize/input.sol"
+object "C_2" {
+    code {
+        {
+            let _1 := memoryguard(0x80)
+            mstore(64, _1)
+            if callvalue() { revert(0, 0) }
+            let _2 := datasize("C_2_deployed")
+            codecopy(_1, dataoffset("C_2_deployed"), _2)
+            return(_1, _2)
+        }
+    }
+    /// @use-src 0:"ir_optimized_with_optimize/input.sol"
+    object "C_2_deployed" {
+        code { { revert(0, 0) } }
+        data ".metadata" hex"<BYTECODE REMOVED>"
+    }
+}

test/cmdlineTests/ir_unoptimized_with_optimize/args

@@ -0,0 +1 @@
+--ir --optimize --debug-info none

test/cmdlineTests/ir_unoptimized_with_optimize/input.sol

@@ -0,0 +1,4 @@
+// SPDX-License-Identifier: GPL-3.0
+pragma solidity *;
+
+contract C {}