Move some util functions to low-level functions.

5 files changed, 320 insertions, 244 deletions

diff --git a/libsolidity/codegen/ArrayUtils.cpp b/libsolidity/codegen/ArrayUtils.cpp
index 352c7177..6f270b4d 100644
--- a/libsolidity/codegen/ArrayUtils.cpp
+++ b/libsolidity/codegen/ArrayUtils.cpp
@@ -502,60 +502,70 @@ void ArrayUtils::copyArrayToMemory(ArrayType const& _sourceType, bool _padToWord
 	}
 }
 
-void ArrayUtils::clearArray(ArrayType const& _type) const
+void ArrayUtils::clearArray(ArrayType const& _typeIn) const
 {
-	unsigned stackHeightStart = m_context.stackHeight();
-	solAssert(_type.location() == DataLocation::Storage, "");
-	if (_type.baseType()->storageBytes() < 32)
-	{
-		solAssert(_type.baseType()->isValueType(), "Invalid storage size for non-value type.");
-		solAssert(_type.baseType()->storageSize() <= 1, "Invalid storage size for type.");
-	}
-	if (_type.baseType()->isValueType())
-		solAssert(_type.baseType()->storageSize() <= 1, "Invalid size for value type.");
-
-	m_context << Instruction::POP; // remove byte offset
-	if (_type.isDynamicallySized())
-		clearDynamicArray(_type);
-	else if (_type.length() == 0 || _type.baseType()->category() == Type::Category::Mapping)
-		m_context << Instruction::POP;
-	else if (_type.baseType()->isValueType() && _type.storageSize() <= 5)
-	{
-		// unroll loop for small arrays @todo choose a good value
-		// Note that we loop over storage slots here, not elements.
-		for (unsigned i = 1; i < _type.storageSize(); ++i)
-			m_context
-				<< u256(0) << Instruction::DUP2 << Instruction::SSTORE
-				<< u256(1) << Instruction::ADD;
-		m_context << u256(0) << Instruction::SWAP1 << Instruction::SSTORE;
-	}
-	else if (!_type.baseType()->isValueType() && _type.length() <= 4)
-	{
-		// unroll loop for small arrays @todo choose a good value
-		solAssert(_type.baseType()->storageBytes() >= 32, "Invalid storage size.");
-		for (unsigned i = 1; i < _type.length(); ++i)
+	TypePointer type = _typeIn.shared_from_this();
+	m_context.callLowLevelFunction(
+		"$clearArray_" + _typeIn.identifier(),
+		2,
+		0,
+		[type](CompilerContext& _context)
 		{
-			m_context << u256(0);
-			StorageItem(m_context, *_type.baseType()).setToZero(SourceLocation(), false);
-			m_context
-				<< Instruction::POP
-				<< u256(_type.baseType()->storageSize()) << Instruction::ADD;
+			ArrayType const& _type = dynamic_cast<ArrayType const&>(*type);
+			unsigned stackHeightStart = _context.stackHeight();
+			solAssert(_type.location() == DataLocation::Storage, "");
+			if (_type.baseType()->storageBytes() < 32)
+			{
+				solAssert(_type.baseType()->isValueType(), "Invalid storage size for non-value type.");
+				solAssert(_type.baseType()->storageSize() <= 1, "Invalid storage size for type.");
+			}
+			if (_type.baseType()->isValueType())
+				solAssert(_type.baseType()->storageSize() <= 1, "Invalid size for value type.");
+
+			_context << Instruction::POP; // remove byte offset
+			if (_type.isDynamicallySized())
+				ArrayUtils(_context).clearDynamicArray(_type);
+			else if (_type.length() == 0 || _type.baseType()->category() == Type::Category::Mapping)
+				_context << Instruction::POP;
+			else if (_type.baseType()->isValueType() && _type.storageSize() <= 5)
+			{
+				// unroll loop for small arrays @todo choose a good value
+				// Note that we loop over storage slots here, not elements.
+				for (unsigned i = 1; i < _type.storageSize(); ++i)
+					_context
+						<< u256(0) << Instruction::DUP2 << Instruction::SSTORE
+						<< u256(1) << Instruction::ADD;
+				_context << u256(0) << Instruction::SWAP1 << Instruction::SSTORE;
+			}
+			else if (!_type.baseType()->isValueType() && _type.length() <= 4)
+			{
+				// unroll loop for small arrays @todo choose a good value
+				solAssert(_type.baseType()->storageBytes() >= 32, "Invalid storage size.");
+				for (unsigned i = 1; i < _type.length(); ++i)
+				{
+					_context << u256(0);
+					StorageItem(_context, *_type.baseType()).setToZero(SourceLocation(), false);
+					_context
+						<< Instruction::POP
+						<< u256(_type.baseType()->storageSize()) << Instruction::ADD;
+				}
+				_context << u256(0);
+				StorageItem(_context, *_type.baseType()).setToZero(SourceLocation(), true);
+			}
+			else
+			{
+				_context << Instruction::DUP1 << _type.length();
+				ArrayUtils(_context).convertLengthToSize(_type);
+				_context << Instruction::ADD << Instruction::SWAP1;
+				if (_type.baseType()->storageBytes() < 32)
+					ArrayUtils(_context).clearStorageLoop(IntegerType(256));
+				else
+					ArrayUtils(_context).clearStorageLoop(*_type.baseType());
+				_context << Instruction::POP;
+			}
+			solAssert(_context.stackHeight() == stackHeightStart - 2, "");
 		}
-		m_context << u256(0);
-		StorageItem(m_context, *_type.baseType()).setToZero(SourceLocation(), true);
-	}
-	else
-	{
-		m_context << Instruction::DUP1 << _type.length();
-		convertLengthToSize(_type);
-		m_context << Instruction::ADD << Instruction::SWAP1;
-		if (_type.baseType()->storageBytes() < 32)
-			clearStorageLoop(IntegerType(256));
-		else
-			clearStorageLoop(*_type.baseType());
-		m_context << Instruction::POP;
-	}
-	solAssert(m_context.stackHeight() == stackHeightStart - 2, "");
+	);
 }
 
 void ArrayUtils::clearDynamicArray(ArrayType const& _type) const
@@ -597,144 +607,154 @@ void ArrayUtils::clearDynamicArray(ArrayType const& _type) const
 	m_context << Instruction::POP;
 }
 
-void ArrayUtils::resizeDynamicArray(ArrayType const& _type) const
+void ArrayUtils::resizeDynamicArray(ArrayType const& _typeIn) const
 {
-	solAssert(_type.location() == DataLocation::Storage, "");
-	solAssert(_type.isDynamicallySized(), "");
-	if (!_type.isByteArray() && _type.baseType()->storageBytes() < 32)
-		solAssert(_type.baseType()->isValueType(), "Invalid storage size for non-value type.");
-
-	unsigned stackHeightStart = m_context.stackHeight();
-	eth::AssemblyItem resizeEnd = m_context.newTag();
-
-	// stack: ref new_length
-	// fetch old length
-	retrieveLength(_type, 1);
-	// stack: ref new_length old_length
-	solAssert(m_context.stackHeight() - stackHeightStart == 3 - 2, "2");
-
-	// Special case for short byte arrays, they are stored together with their length
-	if (_type.isByteArray())
-	{
-		eth::AssemblyItem regularPath = m_context.newTag();
-		// We start by a large case-distinction about the old and new length of the byte array.
-
-		m_context << Instruction::DUP3 << Instruction::SLOAD;
-		// stack: ref new_length current_length ref_value
-
-		solAssert(m_context.stackHeight() - stackHeightStart == 4 - 2, "3");
-		m_context << Instruction::DUP2 << u256(31) << Instruction::LT;
-		eth::AssemblyItem currentIsLong = m_context.appendConditionalJump();
-		m_context << Instruction::DUP3 << u256(31) << Instruction::LT;
-		eth::AssemblyItem newIsLong = m_context.appendConditionalJump();
-
-		// Here: short -> short
-
-		// Compute 1 << (256 - 8 * new_size)
-		eth::AssemblyItem shortToShort = m_context.newTag();
-		m_context << shortToShort;
-		m_context << Instruction::DUP3 << u256(8) << Instruction::MUL;
-		m_context << u256(0x100) << Instruction::SUB;
-		m_context << u256(2) << Instruction::EXP;
-		// Divide and multiply by that value, clearing bits.
-		m_context << Instruction::DUP1 << Instruction::SWAP2;
-		m_context << Instruction::DIV << Instruction::MUL;
-		// Insert 2*length.
-		m_context << Instruction::DUP3 << Instruction::DUP1 << Instruction::ADD;
-		m_context << Instruction::OR;
-		// Store.
-		m_context << Instruction::DUP4 << Instruction::SSTORE;
-		solAssert(m_context.stackHeight() - stackHeightStart == 3 - 2, "3");
-		m_context.appendJumpTo(resizeEnd);
-
-		m_context.adjustStackOffset(1); // we have to do that because of the jumps
-		// Here: short -> long
-
-		m_context << newIsLong;
-		// stack: ref new_length current_length ref_value
-		solAssert(m_context.stackHeight() - stackHeightStart == 4 - 2, "3");
-		// Zero out lower-order byte.
-		m_context << u256(0xff) << Instruction::NOT << Instruction::AND;
-		// Store at data location.
-		m_context << Instruction::DUP4;
-		CompilerUtils(m_context).computeHashStatic();
-		m_context << Instruction::SSTORE;
-		// stack: ref new_length current_length
-		// Store new length: Compule 2*length + 1 and store it.
-		m_context << Instruction::DUP2 << Instruction::DUP1 << Instruction::ADD;
-		m_context << u256(1) << Instruction::ADD;
-		// stack: ref new_length current_length 2*new_length+1
-		m_context << Instruction::DUP4 << Instruction::SSTORE;
-		solAssert(m_context.stackHeight() - stackHeightStart == 3 - 2, "3");
-		m_context.appendJumpTo(resizeEnd);
-
-		m_context.adjustStackOffset(1); // we have to do that because of the jumps
-
-		m_context << currentIsLong;
-		m_context << Instruction::DUP3 << u256(31) << Instruction::LT;
-		m_context.appendConditionalJumpTo(regularPath);
-
-		// Here: long -> short
-		// Read the first word of the data and store it on the stack. Clear the data location and
-		// then jump to the short -> short case.
-
-		// stack: ref new_length current_length ref_value
-		solAssert(m_context.stackHeight() - stackHeightStart == 4 - 2, "3");
-		m_context << Instruction::POP << Instruction::DUP3;
-		CompilerUtils(m_context).computeHashStatic();
-		m_context << Instruction::DUP1 << Instruction::SLOAD << Instruction::SWAP1;
-		// stack: ref new_length current_length first_word data_location
-		m_context << Instruction::DUP3;
-		convertLengthToSize(_type);
-		m_context << Instruction::DUP2 << Instruction::ADD << Instruction::SWAP1;
-		// stack: ref new_length current_length first_word data_location_end data_location
-		clearStorageLoop(IntegerType(256));
-		m_context << Instruction::POP;
-		// stack: ref new_length current_length first_word
-		solAssert(m_context.stackHeight() - stackHeightStart == 4 - 2, "3");
-		m_context.appendJumpTo(shortToShort);
-
-		m_context << regularPath;
-		// stack: ref new_length current_length ref_value
-		m_context << Instruction::POP;
-	}
+	TypePointer type = _typeIn.shared_from_this();
+	m_context.callLowLevelFunction(
+		"$resizeDynamicArray_" + _typeIn.identifier(),
+		2,
+		0,
+		[type](CompilerContext& _context)
+		{
+			ArrayType const& _type = dynamic_cast<ArrayType const&>(*type);
+			solAssert(_type.location() == DataLocation::Storage, "");
+			solAssert(_type.isDynamicallySized(), "");
+			if (!_type.isByteArray() && _type.baseType()->storageBytes() < 32)
+				solAssert(_type.baseType()->isValueType(), "Invalid storage size for non-value type.");
+
+			unsigned stackHeightStart = _context.stackHeight();
+			eth::AssemblyItem resizeEnd = _context.newTag();
+
+			// stack: ref new_length
+			// fetch old length
+			ArrayUtils(_context).retrieveLength(_type, 1);
+			// stack: ref new_length old_length
+			solAssert(_context.stackHeight() - stackHeightStart == 3 - 2, "2");
+
+			// Special case for short byte arrays, they are stored together with their length
+			if (_type.isByteArray())
+			{
+				eth::AssemblyItem regularPath = _context.newTag();
+				// We start by a large case-distinction about the old and new length of the byte array.
+
+				_context << Instruction::DUP3 << Instruction::SLOAD;
+				// stack: ref new_length current_length ref_value
+
+				solAssert(_context.stackHeight() - stackHeightStart == 4 - 2, "3");
+				_context << Instruction::DUP2 << u256(31) << Instruction::LT;
+				eth::AssemblyItem currentIsLong = _context.appendConditionalJump();
+				_context << Instruction::DUP3 << u256(31) << Instruction::LT;
+				eth::AssemblyItem newIsLong = _context.appendConditionalJump();
+
+				// Here: short -> short
+
+				// Compute 1 << (256 - 8 * new_size)
+				eth::AssemblyItem shortToShort = _context.newTag();
+				_context << shortToShort;
+				_context << Instruction::DUP3 << u256(8) << Instruction::MUL;
+				_context << u256(0x100) << Instruction::SUB;
+				_context << u256(2) << Instruction::EXP;
+				// Divide and multiply by that value, clearing bits.
+				_context << Instruction::DUP1 << Instruction::SWAP2;
+				_context << Instruction::DIV << Instruction::MUL;
+				// Insert 2*length.
+				_context << Instruction::DUP3 << Instruction::DUP1 << Instruction::ADD;
+				_context << Instruction::OR;
+				// Store.
+				_context << Instruction::DUP4 << Instruction::SSTORE;
+				solAssert(_context.stackHeight() - stackHeightStart == 3 - 2, "3");
+				_context.appendJumpTo(resizeEnd);
+
+				_context.adjustStackOffset(1); // we have to do that because of the jumps
+				// Here: short -> long
+
+				_context << newIsLong;
+				// stack: ref new_length current_length ref_value
+				solAssert(_context.stackHeight() - stackHeightStart == 4 - 2, "3");
+				// Zero out lower-order byte.
+				_context << u256(0xff) << Instruction::NOT << Instruction::AND;
+				// Store at data location.
+				_context << Instruction::DUP4;
+				CompilerUtils(_context).computeHashStatic();
+				_context << Instruction::SSTORE;
+				// stack: ref new_length current_length
+				// Store new length: Compule 2*length + 1 and store it.
+				_context << Instruction::DUP2 << Instruction::DUP1 << Instruction::ADD;
+				_context << u256(1) << Instruction::ADD;
+				// stack: ref new_length current_length 2*new_length+1
+				_context << Instruction::DUP4 << Instruction::SSTORE;
+				solAssert(_context.stackHeight() - stackHeightStart == 3 - 2, "3");
+				_context.appendJumpTo(resizeEnd);
+
+				_context.adjustStackOffset(1); // we have to do that because of the jumps
+
+				_context << currentIsLong;
+				_context << Instruction::DUP3 << u256(31) << Instruction::LT;
+				_context.appendConditionalJumpTo(regularPath);
+
+				// Here: long -> short
+				// Read the first word of the data and store it on the stack. Clear the data location and
+				// then jump to the short -> short case.
+
+				// stack: ref new_length current_length ref_value
+				solAssert(_context.stackHeight() - stackHeightStart == 4 - 2, "3");
+				_context << Instruction::POP << Instruction::DUP3;
+				CompilerUtils(_context).computeHashStatic();
+				_context << Instruction::DUP1 << Instruction::SLOAD << Instruction::SWAP1;
+				// stack: ref new_length current_length first_word data_location
+				_context << Instruction::DUP3;
+				ArrayUtils(_context).convertLengthToSize(_type);
+				_context << Instruction::DUP2 << Instruction::ADD << Instruction::SWAP1;
+				// stack: ref new_length current_length first_word data_location_end data_location
+				ArrayUtils(_context).clearStorageLoop(IntegerType(256));
+				_context << Instruction::POP;
+				// stack: ref new_length current_length first_word
+				solAssert(_context.stackHeight() - stackHeightStart == 4 - 2, "3");
+				_context.appendJumpTo(shortToShort);
+
+				_context << regularPath;
+				// stack: ref new_length current_length ref_value
+				_context << Instruction::POP;
+			}
 
-	// Change of length for a regular array (i.e. length at location, data at sha3(location)).
-	// stack: ref new_length old_length
-	// store new length
-	m_context << Instruction::DUP2;
-	if (_type.isByteArray())
-		// For a "long" byte array, store length as 2*length+1
-		m_context << Instruction::DUP1 << Instruction::ADD << u256(1) << Instruction::ADD;
-	m_context<< Instruction::DUP4 << Instruction::SSTORE;
-	// skip if size is not reduced
-	m_context << Instruction::DUP2 << Instruction::DUP2
-		<< Instruction::ISZERO << Instruction::GT;
-	m_context.appendConditionalJumpTo(resizeEnd);
-
-	// size reduced, clear the end of the array
-	// stack: ref new_length old_length
-	convertLengthToSize(_type);
-	m_context << Instruction::DUP2;
-	convertLengthToSize(_type);
-	// stack: ref new_length old_size new_size
-	// compute data positions
-	m_context << Instruction::DUP4;
-	CompilerUtils(m_context).computeHashStatic();
-	// stack: ref new_length old_size new_size data_pos
-	m_context << Instruction::SWAP2 << Instruction::DUP3 << Instruction::ADD;
-	// stack: ref new_length data_pos new_size delete_end
-	m_context << Instruction::SWAP2 << Instruction::ADD;
-	// stack: ref new_length delete_end delete_start
-	if (_type.isByteArray() || _type.baseType()->storageBytes() < 32)
-		clearStorageLoop(IntegerType(256));
-	else
-		clearStorageLoop(*_type.baseType());
+			// Change of length for a regular array (i.e. length at location, data at sha3(location)).
+			// stack: ref new_length old_length
+			// store new length
+			_context << Instruction::DUP2;
+			if (_type.isByteArray())
+				// For a "long" byte array, store length as 2*length+1
+				_context << Instruction::DUP1 << Instruction::ADD << u256(1) << Instruction::ADD;
+			_context<< Instruction::DUP4 << Instruction::SSTORE;
+			// skip if size is not reduced
+			_context << Instruction::DUP2 << Instruction::DUP2
+				<< Instruction::ISZERO << Instruction::GT;
+			_context.appendConditionalJumpTo(resizeEnd);
+
+			// size reduced, clear the end of the array
+			// stack: ref new_length old_length
+			ArrayUtils(_context).convertLengthToSize(_type);
+			_context << Instruction::DUP2;
+			ArrayUtils(_context).convertLengthToSize(_type);
+			// stack: ref new_length old_size new_size
+			// compute data positions
+			_context << Instruction::DUP4;
+			CompilerUtils(_context).computeHashStatic();
+			// stack: ref new_length old_size new_size data_pos
+			_context << Instruction::SWAP2 << Instruction::DUP3 << Instruction::ADD;
+			// stack: ref new_length data_pos new_size delete_end
+			_context << Instruction::SWAP2 << Instruction::ADD;
+			// stack: ref new_length delete_end delete_start
+			if (_type.isByteArray() || _type.baseType()->storageBytes() < 32)
+				ArrayUtils(_context).clearStorageLoop(IntegerType(256));
+			else
+				ArrayUtils(_context).clearStorageLoop(*_type.baseType());
 
-	m_context << resizeEnd;
-	// cleanup
-	m_context << Instruction::POP << Instruction::POP << Instruction::POP;
-	solAssert(m_context.stackHeight() == stackHeightStart - 2, "");
+			_context << resizeEnd;
+			// cleanup
+			_context << Instruction::POP << Instruction::POP << Instruction::POP;
+			solAssert(_context.stackHeight() == stackHeightStart - 2, "");
+		}
+	);
 }
 
 void ArrayUtils::clearStorageLoop(Type const& _type) const
diff --git a/libsolidity/codegen/CompilerContext.cpp b/libsolidity/codegen/CompilerContext.cpp
index fcd39b33..dad227c7 100644
--- a/libsolidity/codegen/CompilerContext.cpp
+++ b/libsolidity/codegen/CompilerContext.cpp
@@ -21,15 +21,18 @@
  */
 
 #include <libsolidity/codegen/CompilerContext.h>
-#include <utility>
-#include <numeric>
-#include <boost/algorithm/string/replace.hpp>
+#include <libsolidity/codegen/CompilerUtils.h>
 #include <libsolidity/ast/AST.h>
 #include <libsolidity/codegen/Compiler.h>
 #include <libsolidity/interface/Version.h>
 #include <libsolidity/inlineasm/AsmData.h>
 #include <libsolidity/inlineasm/AsmStack.h>
 
+#include <boost/algorithm/string/replace.hpp>
+
+#include <utility>
+#include <numeric>
+
 using namespace std;
 
 namespace dev
@@ -57,6 +60,51 @@ void CompilerContext::startFunction(Declaration const& _function)
 	*this << functionEntryLabel(_function);
 }
 
+void CompilerContext::callLowLevelFunction(
+	string const& _name,
+	unsigned _inArgs,
+	unsigned _outArgs,
+	function<void(CompilerContext&)> const& _generator
+)
+{
+	eth::AssemblyItem retTag = pushNewTag();
+	CompilerUtils(*this).moveIntoStack(_inArgs);
+
+	auto it = m_lowLevelFunctions.find(_name);
+	if (it == m_lowLevelFunctions.end())
+	{
+		eth::AssemblyItem tag = newTag().pushTag();
+		m_lowLevelFunctions.insert(make_pair(_name, tag));
+		m_lowLevelFunctionGenerationQueue.push(make_tuple(_name, _inArgs, _outArgs, _generator));
+		*this << tag;
+	}
+	else
+		*this << it->second;
+	appendJump(eth::AssemblyItem::JumpType::IntoFunction);
+	adjustStackOffset(_outArgs - 1 - _inArgs);
+	*this << retTag.tag();
+}
+
+void CompilerContext::appendMissingLowLevelFunctions()
+{
+	while (!m_lowLevelFunctionGenerationQueue.empty())
+	{
+		string name;
+		unsigned inArgs;
+		unsigned outArgs;
+		function<void(CompilerContext&)> generator;
+		tie(name, inArgs, outArgs, generator) = m_lowLevelFunctionGenerationQueue.front();
+		m_lowLevelFunctionGenerationQueue.pop();
+
+		setStackOffset(inArgs + 1);
+		*this << m_lowLevelFunctions.at(name).tag();
+		generator(*this);
+		CompilerUtils(*this).moveToStackTop(outArgs);
+		appendJump(eth::AssemblyItem::JumpType::OutOfFunction);
+		solAssert(stackHeight() == outArgs, "Invalid stack height in low-level function " + name + ".");
+	}
+}
+
 void CompilerContext::addVariable(VariableDeclaration const& _declaration,
 								  unsigned _offsetToCurrent)
 {
@@ -125,21 +173,6 @@ Declaration const* CompilerContext::nextFunctionToCompile() const
 	return m_functionCompilationQueue.nextFunctionToCompile();
 }
 
-eth::AssemblyItem const* CompilerContext::lowLevelFunctionEntryPoint(string const& _name) const
-{
-	auto it = m_lowLevelFunctions.find(_name);
-	if (it == m_lowLevelFunctions.end())
-		return nullptr;
-	else
-		return *it;
-}
-
-void CompilerContext::addLowLevelFunction(string const& _name, eth::AssemblyItem const& _label)
-{
-	solAssert(lowLevelFunctionEntryPoint(_name) != nullptr, "Low level function with that name already exists.");
-	m_lowLevelFunctions[_name] = _label.pushTag();
-}
-
 ModifierDefinition const& CompilerContext::functionModifier(string const& _name) const
 {
 	solAssert(!m_inheritanceHierarchy.empty(), "No inheritance hierarchy set.");
diff --git a/libsolidity/codegen/CompilerContext.h b/libsolidity/codegen/CompilerContext.h
index 34befc13..f024b010 100644
--- a/libsolidity/codegen/CompilerContext.h
+++ b/libsolidity/codegen/CompilerContext.h
@@ -22,17 +22,21 @@
 
 #pragma once
 
-#include <ostream>
-#include <stack>
-#include <queue>
-#include <utility>
-#include <libevmasm/Instruction.h>
-#include <libevmasm/Assembly.h>
 #include <libsolidity/ast/ASTForward.h>
 #include <libsolidity/ast/Types.h>
 #include <libsolidity/ast/ASTAnnotations.h>
+
+#include <libevmasm/Instruction.h>
+#include <libevmasm/Assembly.h>
+
 #include <libdevcore/Common.h>
 
+#include <ostream>
+#include <stack>
+#include <queue>
+#include <utility>
+#include <functional>
+
 namespace dev {
 namespace solidity {
 
@@ -90,11 +94,18 @@ public:
 	/// as "having code".
 	void startFunction(Declaration const& _function);
 
-	/// Returns the label of the low level function with the given name or nullptr if it
-	/// does not exist. The lifetime of the returned pointer is short.
-	eth::AssemblyItem const* lowLevelFunctionEntryPoint(std::string const& _name) const;
-	/// Inserts a low level function entry point into the list of low level functions.
-	void addLowLevelFunction(std::string const& _name, eth::AssemblyItem const& _label);
+	/// Appends a call to the named low-level function and inserts the generator into the
+	/// list of low-level-functions to be generated, unless it already exists.
+	/// Note that the generator should not assume that objects are still alive when it is called,
+	/// unless they are guaranteed to be alive for the whole run of the compiler (AST nodes, for example).
+	void callLowLevelFunction(
+		std::string const& _name,
+		unsigned _inArgs,
+		unsigned _outArgs,
+		std::function<void(CompilerContext&)> const& _generator
+	);
+	/// Generates the code for missing low-level functions, i.e. calls the generators passed above.
+	void appendMissingLowLevelFunctions();
 
 	ModifierDefinition const& functionModifier(std::string const& _name) const;
 	/// Returns the distance of the given local variable from the bottom of the stack (of the current function).
@@ -256,6 +267,8 @@ private:
 	size_t m_runtimeSub = -1;
 	/// An index of low-level function labels by name.
 	std::map<std::string, eth::AssemblyItem> m_lowLevelFunctions;
+	/// The queue of low-level functions to generate.
+	std::queue<std::tuple<std::string, unsigned, unsigned, std::function<void(CompilerContext&)>>> m_lowLevelFunctionGenerationQueue;
 };
 
 }
diff --git a/libsolidity/codegen/CompilerUtils.cpp b/libsolidity/codegen/CompilerUtils.cpp
index 7d382aba..caf3b1ac 100644
--- a/libsolidity/codegen/CompilerUtils.cpp
+++ b/libsolidity/codegen/CompilerUtils.cpp
@@ -820,37 +820,46 @@ void CompilerUtils::pushZeroValue(Type const& _type)
 	}
 	solAssert(referenceType->location() == DataLocation::Memory, "");
 
-	m_context << u256(max(32u, _type.calldataEncodedSize()));
-	allocateMemory();
-	m_context << Instruction::DUP1;
+	TypePointer type = _type.shared_from_this();
+	m_context.callLowLevelFunction(
+		"$pushZeroValue_" + referenceType->identifier(),
+		0,
+		1,
+		[type](CompilerContext& _context) {
+			CompilerUtils utils(_context);
+			_context << u256(max(32u, type->calldataEncodedSize()));
+			utils.allocateMemory();
+			_context << Instruction::DUP1;
+
+			if (auto structType = dynamic_cast<StructType const*>(type.get()))
+				for (auto const& member: structType->members(nullptr))
+				{
+					utils.pushZeroValue(*member.type);
+					utils.storeInMemoryDynamic(*member.type);
+				}
+			else if (auto arrayType = dynamic_cast<ArrayType const*>(type.get()))
+			{
+				if (arrayType->isDynamicallySized())
+				{
+					// zero length
+					_context << u256(0);
+					utils.storeInMemoryDynamic(IntegerType(256));
+				}
+				else if (arrayType->length() > 0)
+				{
+					_context << arrayType->length() << Instruction::SWAP1;
+					// stack: items_to_do memory_pos
+					utils.zeroInitialiseMemoryArray(*arrayType);
+					// stack: updated_memory_pos
+				}
+			}
+			else
+				solAssert(false, "Requested initialisation for unknown type: " + type->toString());
 
-	if (auto structType = dynamic_cast<StructType const*>(&_type))
-		for (auto const& member: structType->members(nullptr))
-		{
-			pushZeroValue(*member.type);
-			storeInMemoryDynamic(*member.type);
+			// remove the updated memory pointer
+			_context << Instruction::POP;
 		}
-	else if (auto arrayType = dynamic_cast<ArrayType const*>(&_type))
-	{
-		if (arrayType->isDynamicallySized())
-		{
-			// zero length
-			m_context << u256(0);
-			storeInMemoryDynamic(IntegerType(256));
-		}
-		else if (arrayType->length() > 0)
-		{
-			m_context << arrayType->length() << Instruction::SWAP1;
-			// stack: items_to_do memory_pos
-			zeroInitialiseMemoryArray(*arrayType);
-			// stack: updated_memory_pos
-		}
-	}
-	else
-		solAssert(false, "Requested initialisation for unknown type: " + _type.toString());
-
-	// remove the updated memory pointer
-	m_context << Instruction::POP;
+	);
 }
 
 void CompilerUtils::moveToStackVariable(VariableDeclaration const& _variable)
diff --git a/libsolidity/codegen/ContractCompiler.cpp b/libsolidity/codegen/ContractCompiler.cpp
index bdff0da4..9dc1fb37 100644
--- a/libsolidity/codegen/ContractCompiler.cpp
+++ b/libsolidity/codegen/ContractCompiler.cpp
@@ -827,6 +827,7 @@ void ContractCompiler::appendMissingFunctions()
 		function->accept(*this);
 		solAssert(m_context.nextFunctionToCompile() != function, "Compiled the wrong function?");
 	}
+	m_context.appendMissingLowLevelFunctions();
 }
 
 void ContractCompiler::appendModifierOrFunctionCode()