Merge pull request #9162 from ethereum/memoryEscalator

Memory Escalator

libsolidity/codegen/ir/IRGenerationContext.h

@@ -142,6 +142,9 @@ public:
 
 	std::set<ContractDefinition const*, ASTNode::CompareByID>& subObjectsCreated() { return m_subObjects; }
 
+	bool inlineAssemblySeen() const { return m_inlineAssemblySeen; }
+	void setInlineAssemblySeen() { m_inlineAssemblySeen = true; }
+
 private:
 	langutil::EVMVersion m_evmVersion;
 	RevertStrings m_revertStrings;
@@ -159,6 +162,9 @@ private:
 	MultiUseYulFunctionCollector m_functions;
 	size_t m_varCounter = 0;
 
+	/// Flag indicating whether any inline assembly block was seen.
+	bool m_inlineAssemblySeen = false;
+
 	/// Function definitions queued for code generation. They're the Solidity functions whose calls
 	/// were discovered by the IR generator during AST traversal.
 	/// Note that the queue gets filled in a lazy way - new definitions can be added while the

libsolidity/codegen/ir/IRGenerator.cpp

@@ -92,7 +92,7 @@ string IRGenerator::generate(
 	Whiskers t(R"(
 		object "<CreationObject>" {
 			code {
-				<memoryInit>
+				<memoryInitCreation>
 				<callValueCheck>
 				<?notLibrary>
 				<?constructorHasParams> let <constructorParams> := <copyConstructorArguments>() </constructorHasParams>
@@ -103,7 +103,7 @@ string IRGenerator::generate(
 			}
 			object "<RuntimeObject>" {
 				code {
-					<memoryInit>
+					<memoryInitRuntime>
 					<dispatch>
 					<runtimeFunctions>
 				}
@@ -118,7 +118,6 @@ string IRGenerator::generate(
 		m_context.registerImmutableVariable(*var);
 
 	t("CreationObject", IRNames::creationObject(_contract));
-	t("memoryInit", memoryInit());
 	t("notLibrary", !_contract.isLibrary());
 
 	FunctionDefinition const* constructor = _contract.constructor();
@@ -144,6 +143,10 @@ string IRGenerator::generate(
 	t("functions", m_context.functionCollector().requestedFunctions());
 	t("subObjects", subObjectSources(m_context.subObjectsCreated()));
 
+	// This has to be called only after all other code generation for the creation object is complete.
+	bool creationInvolvesAssembly = m_context.inlineAssemblySeen();
+	t("memoryInitCreation", memoryInit(!creationInvolvesAssembly));
+
 	resetContext(_contract);
 
 	// NOTE: Function pointers can be passed from creation code via storage variables. We need to
@@ -158,6 +161,10 @@ string IRGenerator::generate(
 	generateInternalDispatchFunctions();
 	t("runtimeFunctions", m_context.functionCollector().requestedFunctions());
 	t("runtimeSubObjects", subObjectSources(m_context.subObjectsCreated()));
+
+	// This has to be called only after all other code generation for the runtime object is complete.
+	bool runtimeInvolvesAssembly = m_context.inlineAssemblySeen();
+	t("memoryInitRuntime", memoryInit(!runtimeInvolvesAssembly));
 	return t.render();
 }
 
@@ -651,16 +658,22 @@ string IRGenerator::dispatchRoutine(ContractDefinition const& _contract)
 	return t.render();
 }
 
-string IRGenerator::memoryInit()
+string IRGenerator::memoryInit(bool _useMemoryGuard)
 {
 	// This function should be called at the beginning of the EVM call frame
 	// and thus can assume all memory to be zero, including the contents of
 	// the "zero memory area" (the position CompilerUtils::zeroPointer points to).
 	return
-		Whiskers{"mstore(<memPtr>, <freeMemoryStart>)"}
+		Whiskers{
+			_useMemoryGuard ?
+			"mstore(<memPtr>, memoryguard(<freeMemoryStart>))" :
+			"mstore(<memPtr>, <freeMemoryStart>)"
+		}
 		("memPtr", to_string(CompilerUtils::freeMemoryPointer))
-		("freeMemoryStart", to_string(CompilerUtils::generalPurposeMemoryStart + m_context.reservedMemory()))
-		.render();
+		(
+			"freeMemoryStart",
+			to_string(CompilerUtils::generalPurposeMemoryStart + m_context.reservedMemory())
+		).render();
 }
 
 void IRGenerator::resetContext(ContractDefinition const& _contract)

libsolidity/codegen/ir/IRGenerator.h

@@ -100,7 +100,9 @@ private:
 
 	std::string dispatchRoutine(ContractDefinition const& _contract);
 
-	std::string memoryInit();
+	/// @a _useMemoryGuard If true, use a memory guard, allowing the optimiser
+	/// to perform memory optimizations.
+	std::string memoryInit(bool _useMemoryGuard);
 
 	void resetContext(ContractDefinition const& _contract);
 

libsolidity/codegen/ir/IRGeneratorForStatements.cpp

@@ -1858,6 +1858,7 @@ void IRGeneratorForStatements::endVisit(MemberAccess const& _memberAccess)
 bool IRGeneratorForStatements::visit(InlineAssembly const& _inlineAsm)
 {
 	setLocation(_inlineAsm);
+	m_context.setInlineAssemblySeen();
 	CopyTranslate bodyCopier{_inlineAsm.dialect(), m_context, _inlineAsm.annotation().externalReferences};
 
 	yul::Statement modified = bodyCopier(_inlineAsm.operations());